title: Improved Intermittency Analysis of Single Event Data

abstract:
  The intermittency analysis of single event data (particle moments) in
multiparticle production is improved, taking into account corrections due to
the reconstruction of history of a particle cascade. This approach is tested
within the framework of the $\alpha$-model.


title: The BFKL high energy asymptotics in the next-to-leading approximation

abstract:
  We discuss the high energy asymptotics in the next-to-leading (NLO) BFKL
equation. We find a general solution for Green functions and consider two
properties of the NLO BFKL kernel: running QCD coupling and large NLO
corrections to the conformal part of the kernel. Both of these effects lead to
Regge-BFKL asymptotics only in the limited range of energy ($y = \ln(s/q q_0)
\leq (\as)^{- {5/3}}$) and change the energy behaviour of the amplitude for
higher values of energy. We confirm the oscillation in the total cross section
found in Ref. \cite{ROSS} in the NLO BFKL asymptotics, which shows that the NLO
BFKL has a serious pathology.


title: Quark Mass Hierarchy in the Supersymmetric Composite Model

abstract:
  A mechanism to have the quark mass hierarchy in the supersymmetric composite
model is proposed. The source of the hierarchy is the kinetic-term mixing
between composite quarks. Such mixing can be expected, if quarks are composite
particles. A model in which the mechanism works is constructed, although it is
not perfectly realistic because of some assumptions and unnaturalness.


title: Quark Mixing and CP Violation

abstract:
  We review the historical developments leading to the
Cabibbo-Kobayashi-Maskawa (CKM) quark mixing matrix. Present status of the CKM
matrix from direct measurements is summarized, giving also the present profile
of the unitarity triangle. CP Violation in the $K^0$ - $\bar{K^0}$ complex and
in $B$-meson decays are discussed in the context of the CKM matrix.


title: IR-Renormalon Contributions to the Structure Functions $g_3$ and $g_5$

abstract:
  We calculate the leading $1/N_f$ perturbative contributions to the polarized
nonsinglet structure functions $g_3$ and $g_5$ to all orders in $\alpha_s$. The
contributions from the first renormalon pole are determined. It is a measure
for the ambiguity of the perturbative calculation and is assumed to dominate
the power corrections. The corrections $\Delta g_3$ and $\Delta g_5$ are given
as functions of the Bjorken variable $x$ and turn out to be negligable. The
anomalous dimensions of the leading twist operators are obtained in the
next-to-leading order.


title: Two-loop effects in the evolution of non-forward distributions

abstract:
  We study the effects of next-to-leading order corrections on the evolution of
the twist-two non-forward parton distribution functions in the flavour
non-singlet sector. It is found that the deviation from leading order evolution
is small for all values of the parton momentum fraction variable for moderately
large values of the scale parameter.


title: Gluonic Excitations in Mesons

abstract:
  We report on some interesting recent theoretical and experimental advances on
J^PC exotics and hybrid mesons. These are the decay selection rules governing
J^PC exotic decay, the experimental evidence for a J^PC = 1^-+ exotic in eta pi
and rho pi, and the production of charmonium hybrids at forthcoming
B-factories.


title: Factorization is not violated

abstract:
  We show that existing proofs of factorization imply the cancellation of
certain multiladder contributions that Gotsman, Levin, and Maor had suggested
would invalidate the basic factorization theorem in QCD. No modifications of
the original argument are necessary, although the details of the example offer
useful insight into the mechanisms of factorization.


title: Quantum kinetics and thermalization in an exactly solvable model

abstract:
  We study the dynamics of relaxation and thermalization in an exactly solvable
model with the goal of understanding the effects of off-shell processes. The
focus is to compare the exact evolution of the distribution function with
different approximations to the relaxational dynamics: Boltzmann, non-Markovian
and Markovian quantum kinetics. The time evolution of the distribution function
is evaluated exactly using two methods: time evolution of an initially prepared
density matrix and by solving the Heisenberg equations of motion. There are two
different cases that are studied in detail: i) no stable particle states below
threshold of the bath and a quasiparticle resonance above it and ii) a stable
discrete exact `particle' state below threshold. For the case of quasiparticles
in the continuum (resonances) the exact quasiparticle distribution
asymptotically tends to a statistical equilibrium distribution that differs
from a simple Bose-Einstein form as a result of off-shell processes. In the
case ii), the distribution of particles does not thermalize with the bath. We
study the kinetics of thermalization and relaxation by deriving a non-Markovian
quantum kinetic equation which resums the perturbative series and includes
off-shell effects. A Markovian approximation that includes off-shell
contributions and the usual Boltzmann equation are obtained from the quantum
kinetic equation in the limit of wide separation of time scales upon different
coarse-graining assumptions. The relaxational dynamics predicted by the
non-Markovian, Markovian and Boltzmann approximations are compared to the exact
result of the model. The Boltzmann approach is seen to fail in the case of wide
resonances and when threshold and renormalization effects are important.


title:
More on Electric Dipole Moment Constraints on Phases in the Constrained
  MSSM

abstract:
  We reconsider constraints on $\cp$-violating phases in the Constrained
Minimal Supersymmetric Standard Model. We include the recent calculations of
Ibrahim and Nath on the chromoelectric and purely gluonic contributions to the
quark electric dipole moment and combine cosmological limits on gaugino masses
with experimental bounds on the neutron (and electron) electric dipole moments.
The constraint on the phase of the Higgs mixing mass $\mu$, $|\thm|$, is
dependent on the value of the trilinear mass parameter, $A$, in the model and
on $\tan \beta$. For values of $|A| < 300 \gev$ at the GUT scale, we find
$|\thm|/\pi \la 0.05$, while for $|A| < 1500 \gev$, $|\thm|/\pi \la 0.3$. Thus,
we find that in principle, large CP violating phases are compatible with the
bounds on the electric dipole moments of the neutron and electron, as well as
remaining compatible with the cosmological upper bound on the relic density of
neutralinos. The other $\cp$-violating phase $\tha$ is essentially
unconstrained.


title: New strategies for extracting $V_{ub}$

abstract:
  The prospects for a precise and model independent determination of $|V_{ub}|$
from inclusive and exclusive semileptonic B decays are reviewed.


title:
Quantum generalization of the classical rotating solutions of the O(N)
  model

abstract:
  Analytic solutions of the mean field evolution equations for an N-component
scalar field with O(N) symmetry are presented. These solutions correspond to
rotations in isospin space. They represent generalizations of the classical
solutions obtained earlier by Anselm and Ryskin. As compared to classical
solutions new effects arise because of the coupling between the average value
of the field and quantum fluctuations.


title:
Determining Top Quark CP Violating Dipole Couplings from $e^+e^-\to
  t\bar t$

abstract:
  We show how to determine the electric and weak dipole moments of the top
quark simultaneously and independently from $e^+e^-\to t\bar t$ at
$\sqrt{s}=500$ GeV NLC. To obtain the best accuracies with which the dipole
moments can be measured, we apply the optimal observables to extract the CP
violating effects and consider only purely hadronic, hadronic-leptonic final
state events. Results with left- and right- handed longitudinal polarized as
well as unpolarized electron beams are given. We find that with $50fb^{-1}$
integrated luminosity, the dipole moments can be measured to the accuracy of
$10^{-18}~e~cm$.


title:
An extension of the Statistical Bootstrap Model to include Strangeness.
  Implications on Particle Ratios

abstract:
  The Statistical Bootstrap Model (SBM) is extended to describe hadronic
systems which carry the quantum number of strangeness. The study is conducted
in the three-dimensional space of temperature, up-down and strange chemical
potentials, wherein the existence of a ``critical'' surface is established,
which sets the limits of the hadronic phase of matter. A second surface,
defined by the null expectation value of strangeness number is also determined.
The approach of the latter surface to the critical one becomes the focal point
of the present considerations. Two different versions of the extended SBM are
examined, corresponding to the values 2 and 4 for the exponent, which
determines the asymptotic fall-off of the mass spectrum. It is found that the
version with the value 4 has decisive physical advantages. This model is
subsequently adopted to discuss (strange) particle ratios pertaining to
multiparticle production processes, for which a thermal equilibrium mode of
description applies.


title:
Probing the boundaries of the Hadronic Phase through a Strangeness
  including Statistical Bootstrap Model (S-SBM)

abstract:
  A recently constructed strangeness-including Statistical Bootstrap Model
(S-SBM), which defines the limits of the hadronic phase and provides for a
phase beyond, is further extended so as to include a factor that describes
strangeness suppression. The model is then used to analyse the multiplicity
data from collision experiments in which the colliding entities form isospin
symmetric systems, the primary focus being on S+S interactions (NA35
collaboration). An optimal set of thermodynamical variables is extracted
through a fit to both the inclusive full phase space and midrapidity data. The
assumption that the measured particles originate from a thermally and
partial-chemically equilibrated source described by the S-SBM is satisfactorily
established. The proximity of the thermodynamical variables extracted from the
S+S data to the limits of the hadronic phase is systematically investigated.
Finally, experimental data from proton-antiproton collisions (UA5
collaboration) are similarly analysed.


title:
Model Independent Calculation of ${\cal{B}}({\bar{B}}^0\to D^{(*)+}
  \tau^- {\bar{\nu}})/ {\cal{B}}({\bar{B}}^0\to D^{(*)+} e^- {\bar{\nu}})$

abstract:
  Using the formulas for the $d\Gamma / dq^2$ distribution with non-zero lepton
mass and experimentally determined form factors, we calculate the $d\Gamma
(D^{(*)+} l^- {\bar{\nu}})/ dq^2$ spectra and branching fractions for $l=e$,
$\mu$ and $\tau$. We obtain the results ${\cal{B}}({\bar{B}}^0\rightarrow D^{+}
\tau^- {\bar{\nu}})/ {\cal{B}}({\bar{B}}^0\rightarrow D^{+} e^- {\bar{\nu}})=
0.278^{+0.049}_{-0.035}$ and ${\cal{B}}({\bar{B}}^0\rightarrow D^{*+} \tau^-
{\bar{\nu}})/ {\cal{B}}({\bar{B}}^0\rightarrow D^{*+} e^- {\bar{\nu}})=
0.256^{+0.014}_{-0.013}$ . Since we used the experimentally measured form
factors, these results are independent of theoretical models of form factors.


title: The Anomalous Magnetic Moment of Quarks

abstract:
  In the case of massless current quarks we find that the breaking of chiral
symmetry usually triggers the generation of an anomalous magnetic moment for
the quarks. We show that the kernel of the Ward identity for the vector vertex
yields an important contribution. We compute the anomalous magnetic moment in
several quark models. The results show that it is hard to escape a measurable
anomalous magnetic moment for the quarks in the case of spontaneous chiral
symmetry breaking.


title: Two-loop QCD corrections to top quark width

abstract:
  We present O(alpha_s^2) corrections to the decay t-->bW in the limit of a
very large top quark mass, m_t >> m_W. We find that the O(alpha_s^2) effects
decrease the top quark decay width Gamma_t by about 2%: Gamma_t =
Gamma_0(1-0.8alpha_s(m_t)-1.7alpha_s^2). The complete corrections are smaller
by about 24% than their estimate based on the BLM effects O(beta_0 alpha_s^2).
We explain how to compute a new type of diagrams which contribute to Gamma(t
--> bW) at the O(alpha_s^2) level.


title: NLO Corrections to Heavy Quark Production with Polarized Beams

abstract:
  We present a calculation of the NLO QCD corrections to heavy flavor
photoproduction with longitudinally polarized beams. We apply our results to
study the spin asymmetry for total charm quark production which will be used
for a first direct determination of Delta g by the COMPASS experiment. We also
briefly discuss the main theoretical uncertainties inherent in this
calculation.


title: Comment on ``Understanding the scalar meson quark-antiquark nonet''

abstract:
  It is shown that the incomplete scalar meson nonets found by Toernqvist (T)
and Toernqvist and Roos (TR), employing a new version of the Helsinki
unitarised quark model, should in fact be complete, including an as yet
unconfirmed light K*0 below 1 GeV (old kappa) and the established f0(1500). A
detailed comparison is presented with the predictions of the Nijmegen
unitarised meson model, in which two complete scalar nonets show up below 1.5
GeV. The reason for the flavour-nonet breaking found in T and TR we argue to
originate in the use of coupling constants for the three-meson vertex which are
not independent of flavour. Also some statements made by Toernqvist are
critically reviewed.


title: Signatures of Supersymmetric Q-Balls

abstract:
  In many supersymmetric extensions of the Standard Model the spectrum of
states contains stable non-topological solitons, Q-balls. If formed in the
Early Universe in sufficient amounts, Q-balls now contribute to cold dark
matter. We discuss their experimental signatures and astrophysical
implications.


title: Flavour symmetry of mesonic decay couplings

abstract:
  We present flavour-symmetric results for the couplings of quark-antiquark
systems to meson-meson channels in the harmonic-oscillator expansion. We
tabulate their values for all possible open and closed decay channels of
pseudo-scalar, vector and scalar mesons. We compare the predictions of a model
that employs these flavour-symmetric couplings, both with the results of a
model which uses explicitly flavour-dependent couplings, and with experiment.


title:
Evidence for Substantial Charge Symmetry Violation in Parton
  Distributions

abstract:
  In principle one can test the validity of charge symmetry for parton
distributions by comparing structure functions measured in neutrino and charged
lepton deep inelastic scattering. New experiments make such tests possible;
they provide rather tight upper limits on parton charge symmetry violation
[CSV] for intermediate Bjorken x, but appear to show evidence for CSV effects
at small x. We examine two effects which might account for this experimental
discrepancy: nuclear shadowing corrections for neutrinos, and strange quark
contributions s(x) unequal to sbar(x). We show that neither of these two
corrections removes the experimental discrepancy between the structure
functions. We are therefore forced to consider the possibility of a
surprisingly large CSV effect in the nucleon sea quark distributions.


title:
Two-Loop Results for the Masses of the Neutral CP-Even Higgs Bosons in
  the MSSM

abstract:
  Diagrammatic two-loop results are presented for the leading QCD corrections
to the masses of the neutral CP-even Higgs bosons in the Minimal Supersymmetric
Standard Model (MSSM). The results are valid for arbitrary values of the
parameters of the Higgs and scalar top sector of the MSSM. Their impact on a
precise prediction for the mass of the lightest Higgs boson is briefly
discussed.


title:
Chiral topology in the zero modes enhancement quantum model of the QCD
  vacuum

abstract:
  Using effective potential approach for composite operators we have formulated
quantum model of the QCD vacuum. It is based on the existence and importance of
the nonperturbative $q^{-4}$, topologically nontrivial excitations of the gluon
field configurations there. As a result of this the QCD vacuum is found stable
and it has a stationary state. The value of the scale reponsible for the
nonperturbative dynamics is taken from the bounds for the pion decay constant
in the chiral limit. We have obtained good numerical agreement with the
phenomenological values of the topological susceptibility, the mass of $\eta'$
meson, the gluon condensate. An excellent agreement with the phenomenological
values of the above mentioned quantities is achived by simply summing up our
contributions and instanton-induced contributions due to Negele et al to the
vacuum energy density.


title: Manifestation of metric renormalization in quantum $R^2$--gravity

abstract:
  The renormalization group method in $R^2$-gravity without matter fields is
discussed. A criterion for the existence of the renormalization constant for
the metric has been found, two-loop higher order poles have been calculated, a
relation which allows us to find the one-loop renormalization constant of the
Newtonian constant has been suggested.


title: J/psi production at the Tevatron and HERA: the effect of k_T smearing

abstract:
  We study the effects of intrinsic transverse momentum smearing on J/psi
production both at the Tevatron and at HERA. For the case of large-p_T J/psi
production at the Tevatron, the effects due to k_T smearing are mild. On the
other hand, inelastic J/psi photoproduction at HERA is very sensitive to the
k_T smearing and, in fact, with a reasonable value of <k_T> it is possible to
resolve the large-z discrepancy seen by comparing non-relativistic QCD (NRQCD)
predictions with the HERA data. We conclude that, with the present kinematic
cuts, photoproduction at HERA is not a good test of NRQCD.


title:
Predicting the Pion and Eta Masses as Quantum Corrections without Quark
  Masses

abstract:
  This paper is removed because it used an approximation, which alters some of
the conclusions. Another paper will be written in the near future.


title: Dynamics of Light Antiquarks in the Proton

abstract:
  We present a comprehensive analysis of the recent data from the E866
experiment at Fermilab on Drell-Yan production in pD and pp collisions, which
indicates a non-trivial x-dependence for the asymmetry between u-bar and d-bar
quark distributions in the proton. The relatively fast decrease of the
asymmetry at large x suggests the important role played by the chiral structure
of the nucleon, in particular the pi-N and pi-Delta components of the nucleon
wave function. At small x the data require an additional non-chiral component,
which may be attributed to the Pauli exclusion principle as first suggested by
Field and Feynman.


title: One pion events by atmospheric neutrinos: A three flavor analysis

abstract:
  We study the one-pion events produced via neutral current (NC) and charged
current (CC) interactions by the atmospheric neutrinos. We analyze the ratios
of these events in the framework of oscillations between three neutrino
flavors. The ratios of the CC events induced by $\nu_e$ to that of the NC
events and a similar ratio defined with $\nu_\mu$ help us in distinguishing the
different regions of the neutrino parameter space.


title: Quark Gluon Plasma in a+a Collisions at CERN SPS

abstract:
  A brief review of a history of data collection and interpretation of the
results on high energy A+A collisions is presented. Basic assumptions and main
results of a statistical model of the early stage of the A+A collisions are
discussed. It is concluded that a broad set of experimental data is in
agreement with the hypothesis that QGP is created in central A+A (S+S and
Pb+Pb) collisions at the SPS. Carefull experimental investigation of the A+A
collisions in the energy region between top AGS and SPS energies is needed.


title: Perturbative QCD calculations with heavy quarks

abstract:
  We review recent calculations of second order corrections to heavy quark
decays. Techniques developed in this context are applicable to many processes
involving heavy charged particles, for example the nonabelian dipole radiation.
Calculations involving relativistic radiating particles are also discussed.


title: Hard-scattering factorization with heavy quarks: A general treatment

abstract:
  A detailed proof of hard scattering factorization is given with the inclusion
of heavy quark masses. Although the proof is explicitly given for
deep-inelastic scattering, the methods apply more generally The
power-suppressed corrections to the factorization formula are uniformly
suppressed by a power of \Lambda/Q, independently of the size of heavy quark
masses, M, relative to Q.


title:
Diffractive J/Psi production in high energy gamma-gamma collisions as a
  probe of the QCD pomeron

abstract:
  The reaction \gamma\gamma ---> J/Psi J/Psi is discussed assuming dominance of
the QCD BFKL pomeron exchange. We give prediction for the cross-section of this
process for LEP2 and TESLA energies. We solve the BFKL equation in the
non-forward configuration taking into account dominant non-leading effects
which come from the requirement that the virtuality of the exchanged gluons
along the gluon ladder is controlled by their transverse momentum squared. We
compare our results with those corresponding to the simple two gluon exchange
mechanism and with the BFKL pomeron exchange in the leading logarithmic
approximation. The BFKL effects are found to generate a steeper t-dependence
than the two gluon exchange. The cross-section is found to increase with
increasing CM energy W as (W^2)^{2\lambda}. The parameter \lambda is slowly
varying with W and takes the values lambda \sim 0.23 - 0.28. The magnitude of
the total cross-section for the process \gamma\gamma --> J/Psi J/Psi is found
to increase from 4 to 26 pb within the energy range accessible at LEP2. The
magnitude of the total cross-section for the process e^+e^- ---> e^+e^- J/Psi
J/Psi with antitagged e^+ and e^- is estimated to be around 0.1 pb at LEP2.


title: Rapidity Distributions of Jets Produced in Heavy Ion Collisions at LHC

abstract:
  We discuss the rapidity distribution of produced jets in heavy-ion collisions
at LHC. The process allows one to determine to a good accuracy the value of the
impact parameter of the nuclear collision in each single inelastic event. The
knowledge of the geometry is a powerful tool for a detailed analysis of the
process, making it possible to test the various different elements which, in
accordance with present theoretical ideas, take part to the production
mechanism.


title:
What does the W p_T distribution tell us about the W + 1 jet / W + 0 jet
  ratio at the Tevatron ?

abstract:
  We show that the W p_T distribution measured by D0 at the Tevatron agrees
well with the NLO QCD theoretical prediction for this quantity, whilst the W +
1 jet/ W + 0 jet ratio, R^10, measured by D0 lies significantly above the NLO
QCD theoretical prediction. We derive an approximate relationship between these
two quantities, and show that this rules out the majority of theoretical
explanations for the D0 excess in R^10. We discuss possible physics that could
give rise to the R^10 excess, which have little effect on the W p_T.


title: The Standard Model from extra dimensions

abstract:
  We present a simple N=1 five-dimensional model where the fifth dimension is
compactified on the orbifold $S^1/Z_2$. Non-chiral matter lives in the bulk of
the fifth dimension (five dimensions) while chiral matter lives on the fixed
points of the orbifold (four-dimensional boundaries). The massless sector
constitutes the Minimal Supersymmetric Standard Model while the massive modes
rearrange in N=2 supermultiplets. After supersymmetry breaking by the
Scherk-Schwarz mechanism the zero modes can be reduced to the
non-supersymmetric Standard Model.


title: Validity of Flavor Symmetry and Charge Symmetry for Parton Distributions

abstract:
  Recent experimental measurements of the Gottfried Sum Rule, and pp and pD
Drell-Yan processes, suggest significant violation of flavor symmetry in the
proton sea. This interpretation rests on the assumption of parton charge
symmetry. Our model calculations suggest charge symmetry violation [CSV] for
parton valence distributions of a few percent. Precision measurements of
structure functions in muon and neutrino experiments allow us to set rather
stringent experimental limits on CSV in certain kinematic regions. In another
region, these experiments suggest substantial CSV effects. We suggest
experiments which could test parton CSV.


title:
Spin Dependence of Associated Production of a Prompt Photon and a Charm
  Quark at Next-to-Leading Order in QCD

abstract:
  A second order, $O(\alpha ^2_s)$, calculation in perturbative quantum
chromodynamics is presented of the longitudinal spin dependence of the cross
section for the two particle inclusive reaction $p + p \to \gamma + c + X$ for
large values of the transverse momentum of the prompt photon and charm quark.
Differential distributions are provided for the spin-averaged cross section and
for the two-spin longitudinal polarization asymmetry $A_{LL}$ at the energy of
the Brookhaven Relativistic Heavy Ion Collider. An assessment is given of the
prospects for determination of the spin dependence of the charm quark density.


title: The Phenomenology of Enhanced b->sg

abstract:
  Potential hints for New Physics enhanced b -> sg dipole operators are
reviewed. Implications for inclusive kaon spectra, and corrresponding search
strategies are discussed. Remarkably, all B meson rare decay constraints can be
evaded. Large CP asymmetries are expected if new contributions to the dipole
operators contain non-trivial weak phases. A critical comparison of eta'
production in the Standard Model and in models with enhanced b -> sg is
presented. A Standard Model explanation of the large B -> eta' Xs rate measured
by CLEO poses a challenge, evidently requiring novel non-perturbative order of
magnitude enhancement of gluon anomaly mediated contributions. However, in the
case of enhanced b -> sg the existence of a cocktail solution is very likely.


title: Study of Nondiagonal Parton Distribution Models

abstract:
  In this paper we examine predictions from different models of nondiagonal
parton distributions. This will be achieved by examining whether certain
predictions of relationships between diagonal and nondiagonal parton
distributions also hold after having evolved the different distributions.


title: New possibilities of old soft pomeron in DIS

abstract:
  A traditional Regge model with a $Q^2$-independent Pomeron intercept closed
(or equal) to one is constructed in order to describe the available data on the
proton structure function. A Dipole Pomeron model which does not explicitly
violate unitarity is developed and investigated. An excellent agreement with
the 1209 data is found ($\chi^2/{dof}=1.11$) in the whole kinematical domain
investigated by experiments. A comparison of the model with already existing
ones is made. The $x-$, $Q^2-$slopes and the effective intercept are discussed
as $Q^2$ and $x$ functions.


title: The minimum area, the flux tube, and Thomas precession

abstract:
  Quark confinement in Buchm\"{u}ller's picture of a rotating flux tube is
reconsidered in the context of a minimum area evaluation of the Wilson loop.
The question is asked whether resulting spin independent dynamics are
consistent with Thomas precessional spin dependence leading from electric
confinement. The answer appears to be in the negative; self-consistency of the
picture found in the literature is examined and explained in simple classical
terms, with illustrations.


title: Nonfactorization in Cabibbo-Favored B Decays

abstract:
  We assume universal values for the color-singlet ($\epsilon_1$) and color
octet ($\epsilon_8$) nonfactorization parameters in B Decays. Two sets of
color-favored processes and one set of color-suppressed processes were used to
give quantitative estimates of these parameters. It has been found (by
calculating the branching ratios for a large number of Cabibbo-favored B
Decays) that the values $\epsilon_1(\mu_0) = - 0.06 +/- 0.03$ and
$\epsilon_8(\mu_0) = 0.12 +/- 0.02$ improve significantly the predictions of
the factorization model.


title:
Understanding the success of nonrelativistic potential models for
  relativistic quark-antiquark bound states

abstract:
  We investigate the connection between relativistic potential models for
quark-antiquark bound states and the nonrelativistic models that have been used
successfully to fit and predict the spectra of relativistic systems. We use
Martin's operator inequality \sqrt{p^2+m^2} <= (p^2+M^2+m^2)/2M to motivate the
approximation of the relativistic kinetic energy terms in the spinless Salpeter
equation by expressions of the nonrelativistic form M+\epsilon+p^2/2M for each
quark. To investigate the validity of the resulting approximation numerically,
we generate energy spectra for q\bar{q} mesons composed of two light or two
heavy quarks using the spinless Salpeter equation with the linear-plus-Coulomb
potential, and then fit the lowest few states of each type using the effective
Schr\"{o}dinger description with the same potential. We find good fits to the
lowest four calculated c\bar{c} and the lowest three s\bar{s} states either
taking M fixed at the value M_q=\sqrt{<p^2> +m_q^2}, or allowing M_q to vary in
the fit. The energies of the lowest few c\bar{s} states are then predicted with
similar accuracy. The reasons for the success of the nonrelativistic
approximation are identified, and explain the success of Martin's
nonrelativistic predictions for the spectra of relativistic light-heavy mesons.
However, we note that the agreement between the nonrelativistic and
relativistic wave functions is not good, a point of potential concern for the
calculation of transition matrix elements.


title: Radiative neutrino mass matrix for three active plus one sterile species

abstract:
  A simple unifying mass matrix is presented for the three active and one
sterile neutrinos $\nu_e$, $\nu_\mu$, $\nu_\tau$ and $\nu_s$, using an
extension of the radiative mechanism proposed some time ago by Zee. The total
neutrino-oscillation data are explained by the scheme $\nu_e \leftrightarrow
\nu_s$ (solar), $\nu_\mu \leftrightarrow \nu_\tau$ (atmospheric) and $\nu_e
\leftrightarrow \nu_\mu$ (LSND). We obtain the interesting approximate
relationship $(\Delta m^2)_{atm} \simeq 2[(\Delta m^2)_{solar} (\Delta
m^2)_{LSND}]^{1/2}$ which is well satisfied by the data.


title:
A New Model of Direct Gauge Mediation with an Affine Quantum Moduli
  Space

abstract:
  We present a new, simple supersymmetry breaking model with direct gauge
mediation. Supersymmetry breaking sector is based on the model with an Affine
quantum moduli space. The model has no gauge messengers and no light scalars
charged under the Standard Model which give a negative contribution to the soft
masses. Large expectation value at the minimum is obtained by balancing the
runaway potential and the dimension six nonrenormalizable term. This makes it
easy to preserve the perturbative unification. Enough suppression of the
supergravity contribution to the soft masses can also be shown.


title: A reincarnation of R-parity

abstract:
  In supersymmetric theories, R-parity is defined in a way such that it does
not commute with the space-time symmetries. We show that, in general
sypersymmetric models, one can define a discrete symmetry which commutes with
all space-time and gauge symmetries, and whose phenomenological implications
are equivalent to those of R-parity.


title:
Properties of $N^*$(1535) at Finite Density in the Extended
  Parity-Doublet Models

abstract:
  We improve so called ``naive'' and ``mirror'' models for the positive and
negative parity nucleons, $N$ and $N^{*}$, by introducing nonlinear terms
allowed by chiral symmetry. Both models in this improvement reproduce the
observed nucleon axial charge in free space and reveal interesting density
dependence of the axial charges for $N$ and $N^*$, and the doublet masses. A
remarkable difference between the two models is found in the off-diagonal axial
charge, $g_{ANN^*}$, which could appear either as suppression or as enhancement
of $N^* \to \pi N$ decay in the medium.


title: Spin asymmetries at RHIC and polarized parton distributions

abstract:
  We discuss polarized parton distributions and their effects on spin
asymmetries at RHIC. In particular, transversity distributions and transverse
spin asymmetry are studied. First, we show the $Q^2$ evolution difference
between a transversity distribution and a corresponding longitudinally
polarized distribution. The difference could be an important test of
perturbative QCD in high-energy spin physics. Then, the transverse spin
asymmetry $A_{TT}$ is calculated with possible transversity distributions.
Next, we study antiquark flavor asymmetry $\Delta_{_T} \bar u/ \Delta_{_T} \bar
d$ in the transversity distributions by using a simple model. Its effects on
the transverse spin asymmetry are also discussed.


title:
Model independent determination of the light-cone wave functions for
  exclusive processes

abstract:
  We present a method to compute, by numerical simulations of lattice QCD, the
light-cone wave functions which enter exclusive processes at large momentum
transfer, such as electromagnetic elastic scatterings, or exclusive
semi-leptonic decays as B -> pi (B -> rho) and radiative decays as B -> K*
gamma. The method is based on first principles and does not require any model
assumption.


title:
Generalized Factorization in Non-leptonic Two-Body B-Decays: a Critical
  Look

abstract:
  We reanalyze critically the generalized factorization hypothesis in
non-leptonic two-body B-decays discussed recently by several authors. In
particular we address the determination of the factorization scale $\mu_f$ and
of the non-perturbative parameters $\xi^{NF}_1 (m_b)$ and $\xi^{NF}_2 (m_b)$
which are supposed to measure non-factorizable contributions to hadronic matrix
elements with $\xi^{NF}_i (\mu_f) = 0$. We emphasize that both $\mu_f$ and
$\xi^{NF}_i (m_b)$ are renormalization scheme dependent and we demonstrate
analytically and numerically that for any chosen scale $\mu_f=\ord(m_b)$ it is
possible to find a renormalization scheme for which $\xi^{NF}_1 (\mu_f) =
\xi^{NF}_2 (\mu_f)=0$. The existing data indicate that such "factorization
schemes" differ from the commonly used schemes NDR and HV. Similarly we point
out that the recent extractions of the effective number of colours $N^{eff}$
from two-body non-leptonic B-decays while $\mu$ and renormalization scheme
independent suffer from gauge dependences and infrared dependences.


title: Chargino Pair Production in $e^+e^-$ Collisions

abstract:
  Charginos $\chi_1^\pm$ are expected to be the lightest observable
supersymmetric particles in many supersymmetric models. We present a procedure
which will allow to determine the chargino mixing angles and, subsequently, the
fundamental SUSY parameters $M_2, \mu$ and $\tan\beta$ by measurements of the
total cross section and the spin correlations in $e^+e^-$ annihilation to
$\chi_1^+ \chi_1^-$ chargino pairs.


title: Harmonic sums, Mellin transforms and Integrals

abstract:
  This paper describes algorithms to deal with nested symbolic sums over
combinations of harmonic series, binomial coefficients and denominators. In
addition it treats Mellin transforms and the inverse Mellin transformation for
functions that are encountered in Feynman diagram calculations. Together with
results for the values of the higher harmonic series at infinity the presented
algorithms can be used for the symbolic evaluation of whole classes of
integrals that were thus far intractable. Also many of the sums that had to be
evaluated seem to involve new results. Most of the algorithms have been
programmed in the language of FORM. The resulting set of procedures is called
SUMMER.


title: Dilaton Stabilisation in $D$-term Inflation

abstract:
  Dilaton stabilisation is usually considered to pose a serious obstacle to
successful $D$-term inflation in superstring theories. We argue that the
physics of gaugino condensation is likely to be modified during the
inflationary phase in such a way as to enhance the gaugino condensation scale.
This enables dilaton stabilisation during inflation with the $D$-term still
dominating the vacuum energy at the stable minimum.


title:
Higgs-mediated flavor-changing neutral currents in the general framework
  with two Higgs doublets -- an RGE analysis

abstract:
  We consider the standard model with two Higgs doublets with the most general
Yukawa coupling terms (``type III''). In the model, the neutral-Higgs-mediated
flavor-changing neutral currents (FCNC's) are allowed, but must be reasonably
suppressed at low energies of probes. It has been known that the existing
hierarchies of quark masses render this suppression at low energies rather
natural. On the other hand, the model has been regarded by many as unnatural
because of the absence of any symmetry that would ensure persistence of this
suppression as the energy of probes increases. The opinion has been based on
the expectation that the mentioned FCNC's would increase by large factors at
increasing energies. We performed a numerical analysis of the flow of these FCN
coupling parameters as governed by the one-loop renormalization group equations
(RGE's), in a simplified case when Yukawa couplings of the first quark
generation are neglected. The analysis shows a remarkable persistence of the
mentioned FCNC suppression and thus indicates that the model is not unnatural
in the RGE sense. Further, we point out two mistakes in the Yukawa RGE's of
Machacek and Vaughn at one-loop level.


title: Diffractive Production of Drell-Yan pairs and Heavy Flavors

abstract:
  Partonic interpretation of high-energy reactions is known to depend on a
reference frame. Particularly, in the rest frame of the target Drell-Yan
process looks like freeing of the projectile lepton-antilepton fluctuation,
rather than q+qbar -> l+lbar annihilation. The light-cone representation for
Drell-Yan reaction is very similar to that in DIS and exposes a substantial
contamination of soft interactions, which turn out to be dominant in
diffractive production of lepton pairs and in nuclear shadowing. We estimate
the fraction of diffractive events in the total Drell-Yan cross section, which
scales in M^2, and find a substantial deviation from factorization. An
analogous approach is developed for diffractive production of heavy flavors.


title: Energy Dependence of the Pomeron Spin-Flip

abstract:
  There is no theoretical reason to think that the spin-flip component of the
Pomeron is zero. One can measure the spin-flip part using Coulomb-nuclear
interference (CNI). Perturbative QCD calculations show that the spin-flip
component is sensitive to the smallest quark separation in the proton, while
the non-flip part probes the largest separation. According to HERA results on
the proton structure function at very low x the energy dependence of the
cross-section correlates with the size of the color dipole. Analysing the data
from HERA we predict that the ratio of the spin-flip to non-flip amplitude
grows with energy as $r(s)\propto (1/x)^{0.1-0.2}$, violating Regge
factorisation of the Pomeron.


title: Highlights of the Theory

abstract:
  The highlights of the Working Group 5B, Theory, are summarised. There has
been reported impressive progresses in the study of BFKL Pomeron and Odderon
dynamics. It turns out that the leading log approximation is not still a good
one in the energy range of HERA and one should take care of next to leading
corrections.


title: Unitarity and the scale of fermion mass generation

abstract:
  We study the upper bound on the scale of fermion mass generation in a
two-Higgs-doublet model. If the model is weakly-coupled, the scale of fermion
mass generation is much less than the Appelquist-Chanowitz unitarity bound.
However, if we allow some dimensionless Higgs self-couplings to become large,
the Appelquist-Chanowitz unitarity bound can be saturated. The unitarity bound
on the scale of top-quark mass generation is about 3 TeV, which may be within
the reach of future colliders.


title: A Heavy Top Quark From Flavor-Universal Colorons

abstract:
  Ordinary technicolor and extended technicolor cannot produce the heavy top
quark unaided. We demonstrate that a flavor-universal extension of the color
interactions combined with an extended hypercharge sector that singles out the
third generation can provide the necessary assistance. We discuss current
experimental constraints and suggest how collider experiments can search for
the predicted new heavy gauge bosons.


title:
Limits on R-parity non-conservation in MSSM with gauge mediated
  supersymmetry breaking from the neutrinoless double beta decay

abstract:
  The R-parity non-conservation phenomenology within the minimal supersymmetric
standard model with gauge mediated supersymmetry breaking has been studied. New
constraints on the lepton number violating constant $\lambda_{111}^\prime$ were
imposed by non-observability of the neutrinoless double beta decay. We find
that $\lambda_{111}^\prime$ depends strongly on the effective supersymmetry
breaking scale $\Lambda$ only and deduce limits which are much stronger than
those previously found in literature.


title: Effective Field Theory of Vacuum Tilting

abstract:
  Simple models of topcolor and topcolor-assisted technicolor rely on a
relatively strong U(1) gauge interaction to ``tilt'' the vacuum. This tilting
is necessary to produce a top-condensate, thereby naturally obtaining a heavy
top-quark, and to avoid producing a bottom-condensate. We identify some
peculiarities of the Nambu-Jona-Lasinio approximation often used to analyze the
topcolor dynamics. We resolve these puzzles by constructing the low-energy
effective field theory appropriate to a mass-independent renormalization
scheme. We construct the power-counting rules for such an effective theory. By
requiring that the Landau pole associated with the U(1) gauge theory be
sufficiently above the topcolor gauge boson scale, we derive an upper bound on
the strength of the U(1) gauge-coupling evaluated at the topcolor scale. The
upper bound on the U(1) coupling implies that these interactions can shift the
composite Higgs boson mass-squared by only a few per cent and, therefore, that
the topcolor coupling must be adjusted to equal the critical value for chiral
symmetry breaking to within a few per cent.


title:
LHC Reach for Gauge Mediated Supersymmetry Breaking Models Via Prompt
  Photon Channels

abstract:
  We evaluate the supersymmetry reach of the Large Hadron Collider within the
gauge-mediated low energy supersymmetry breaking framework, assuming that a
neutralino is the second lightest sparticle and that it decays promptly into a
gravitino which escapes detection. We find that the maximum reach is obtained
via a search for inclusive $\gamma\gamma+\eslt$ events coming dominantly from
chargino and neutralino production. Assuming an integrated luminosity of
10~$fb^{-1}$, we find that LHC experiments will be able to probe values of the
model parameter $\Lambda \alt 400$ TeV, corresponding to $m_{\tg} \leq 2.8$
TeV. A measure of the model parameter $\Lambda$ may be possible from the photon
$p_T$ spectrum.


title:
Survey of recent data on photon structure functions and resolved photon
  processes

abstract:
  Present data on the partonic content of the photon are reviewed. The results
on the unpolarized structure functions from DIS experiments and on large pt jet
production processes in gamma-gamma and gamma-p collisions are discussed for
both real and virtual photons. A few related topics like the QED structure
functions of the photon and the structure function of the electron are also
shortly discussed.


title: Grand Unification at Intermediate Mass Scales through Extra Dimensions

abstract:
  One of the drawbacks of conventional grand unification scenarios has been
that the unification scale is too high to permit direct exploration. In this
paper, we show that the unification scale can be significantly lowered (perhaps
even to the TeV scale) through the appearance of extra spacetime dimensions.
Such extra dimensions are a natural consequence of string theories with
large-radius compactifications. We show that extra spacetime dimensions
naturally lead to gauge coupling unification at intermediate mass scales, and
moreover may provide a natural mechanism for explaining the fermion mass
hierarchy by permitting the fermion masses to evolve with a power-law
dependence on the mass scale. We also show that proton-decay constraints may be
satisfied in our scenario due to the higher-dimensional cancellation of
proton-decay amplitudes to all orders in perturbation theory. Finally, we
extend these results by considering theories without supersymmetry;
experimental collider signatures; and embeddings into string theory. The latter
also enables us to develop several novel methods of explaining the fermion mass
hierarchy via $D$-branes. Our results therefore suggest a new approach towards
understanding the physics of grand unification as well as the phenomenology of
large-radius string compactifications.


title: Indirect Detection of Dark Matter in km-size Neutrino Telescopes

abstract:
  Neutrino telescopes of kilometer size are currently being planned. They will
be two or three orders of magnitude bigger than presently operating detectors,
but they will have a much higher muon energy threshold. We discuss the
trade-off between area and energy threshold for indirect detection of
neutralino dark matter captured in the Sun and in the Earth and annihilating
into high energy neutrinos. We also study the effect of a higher threshold on
the complementarity of different searches for supersymmetric dark matter.


title:
Atmospheric neutrino oscillations and maximal nu_mu-nu_tau mixing in
  unified models

abstract:
  The recent data describing the evidence for neutrino oscillations by Super
Kamiokande implies that two neutrinos are very strongly mixed. We ask the
question: can approximate maximal neutrino mixing be natural in unified (GUT or
string) models? We attempt to answer this question in as much generality as
possible. Without specifying a particular model, we are able to show that a
gauged family symmetry can naturally provide the required maximal mixing
between mu and tau neutrinos. The second and third family neutrino mass
eigenstates are almost degenerate with masses of order 0.2 eV.


title:
Secondary Reggeons in Diffractive Deep Inelastic Scattering - the
  Microscopic QCD Evaluation

abstract:
  We present the microscopic QCD evaluation of the secondary reggeon
contribution to diffractive DIS. It is shown that the interference between
Pomeron and Reggeon enters in the maximal possible way. In the region of large
$\beta \simeq 1$ it is shown, that the structure functions of the Reggeon and
Pomeron as well as the Reggeon-Pomeron interference SF have a universal $\sim
(1-\beta)^2$ behaviour.


title:
The Impact of NLO-Corrections on the Determination of the
  $\bar{u},\bar{d} Content of Nucleons from Drell-Yan Production

abstract:
  The interpretation of Drell-Yan production in terms of the antiquark
densities depends on NLO corrections. Besides the NLO corrections to the
familiar annihilation $q\bar{q}\to \gamma^* \to l^+ l^-$, there is a
substantial contribution from the QCD Compton subprocesses $gq \to q\gamma^*
\to q l^+ l^-$ and $g\bar{q} \to q\gamma^* \to q l^+ l^-$. The beam and target
dependence of the two classes of corrections is different. We discuss the
impact of this difference on the determination of the $\bar{d}-\bar{u}$
asymmetry in the proton from the comparison of the $pp$ and $pn$ Drell-Yan
production.


title: The Tensor Structure Function $b_2(x,Q^2)$ of the Deuteron at Small x

abstract:
  The dependence of the diffractive nuclear shadowing and the nuclear pion
excess effect on the deuteron spin alignment leads to a substantial tensor
polarisation of sea partons in the deuteron. The corresponding tensor structure
function $b_2(x,Q^2)$ rises towards small $x$, and we predict the about one
percent tensor asymmetry $A_2(x,Q^2) =b_2(x,Q^2)/F_{2D}(x,Q^2)$. We calculate
the shadowing of the gluon distribution in the deuteron for two different
pomeron gluon-distributions. For a hard gluon dominated $\Pom$-structure
function, as advocated by H1, we find large gluon shadowing, which appears to
be in conflict with the DGLAP analysis of nuclear SF's.


title:
Diffractive deeply inelastic scattering of hadronic states with small
  transverse size

abstract:
  Diffractive deeply inelastic scattering from a hadron is described in terms
of diffractive quark and gluon distributions. If the transverse size of the
hadronic state is sufficiently small, these distributions are calculable using
perturbation theory. We present such a calculation and discuss the underlying
dynamics. We comment on the relation between this dynamics and the pattern of
scaling violation observed in the hard diffraction of large-size states at
HERA.


title: SUSY-QCD corrections to stop and sbottom decays into Higgs bosons

abstract:
  We calculate the order(\alpha_s) SUSY-QCD corrections to the widths of stop
and sbottom decays into Higgs bosons within the Minimal Supersymmetric Standard
Model. We give the complete analytical formulae paying particular attention to
the on-shell renormalization of the soft SUSY-breaking parameters. We also
perform a detailed numerical analysis of both stop and sbottom decays into all
Higgs bosons h^0, H^0, A^0, and H^\pm. We find that the SUSY-QCD corrections
are significant, mostly negative and of the order of a few ten percent.


title: Surface Tension at Finite Tempearture in the MIT Bag Model

abstract:
  At $ T = 0 $ the surface tension $ \sigma ^{1/3} $ in the MIT bag model for a
single hadron is known to be negligible as compared to the bag pressure $
B^{1/4}$. We show that at finite temperature it has a substantial value of 50 -
70 MeV which also differ from hadron to hadron. We also find that the dynamics
of the Quark-Gluon Plasma is such that the creation of hybrids $(s\bar{s}g)$
with massive quarks will predominate over the creation of $ (s\bar{s}) $
mesons.


title: Lower Bounds on Charged Higgs Bosons from LEP and the TEVATRON

abstract:
  We point out that charged Higgs bosons can decay into final states different
than $\tau^+ \nu_\tau$ and $c \bar{s}$, even when they are light enough to be
produced at LEPII or at the Tevatron, through top-quark decays. These
additional decay modes are overlooked in ongoing searches even though they
alter the existing lower bounds on the mass of charged Higgs bosons that are
present in supersymmetric and two Higgs doublets models.


title:
The Multiplicity of Heavy Quark Pairs from Gluon Splitting in e+e-
  Annihilation

abstract:
  I will briefly review the progress which has been made in the investigation
of secondary heavy quark production at LEP. I will show why a calculation of
the secondary heavy quark multiplicity, keeping the dependence on an event
shape variable, is essential for better exploitation of data, and I will
present the results of such a calculation. This will be compared to Monte Carlo
studies.


title: Effective Field Theory

abstract:
  These lectures provide an introduction to the basic ideas and methods of
Effective Field Theory, and a description of a few interesting phenomenological
applications in particle physics. The main conceptual foundations are discussed
in sections 2 and 3, which cover the momentum expansion and the most important
issues associated with the renormalization process. Section 4 presents an
overview of Chiral Perturbation Theory, the low-energy realization of Quantum
Chromodynamics in the light quark sector. The Chiral Perturbation Theory
framework is applied to weak transitions in section 5, where the physics of
non-leptonic kaon decays is analyzed. The so-called Heavy Quark Effective
Theory is briefly discussed in section 6. The electroweak chiral Effective
Field Theory is described in section 7, which contains a brief overview of the
effective Lagrangian associated with the spontaneous electroweak symmetry
breaking. Some summarizing comments are finally given in section 8.


title: Two-loop QCD corrections to Higgs-pair production at the LHC

abstract:
  The calculation of the next-to-leading order QCD corrections to the
production of a neutral Higgs-boson pair is briefly summarized. The dominant
production mechanism is gluon fusion via top-quark loops, so that the QCD
corrections can be considered, to good approximation, in the limit of a heavy
top-quark mass.


title: Virtual Compton Scattering off the nucleon

abstract:
  We review the recent developments of virtual Compton scattering. We focus on
the kinematical regimes which look the most promising. The threshold regime
gives access to the generalized polarizabilities of the proton. The hard
scattering regime allows tests of perturbative QCD predictions and of the
valence quark wave function. The Bjorken regime is closely related to deep
inelastic scattering. It gives access to the off-forward parton distributions
which generalize the ordinary parton distributions and may shed a new light on
the spin problem. For each regime we discuss the experimental perspectives and
the role of the Bethe-Heitler background.


title:
The spin density matrix of top quark pairs produced in electron-positron
  annihilation including QCD radiative corrections

abstract:
  We calculate the spin density matrix of top quark pairs for the reaction
$e^+e^-\to t\bar{t}X$ to order $\alpha_s$. As an application we show
next-to-leading order results for a variety of spin observables for the
$t\bar{t}$ system. These include the top quark and antiquark polarizations and
$t\bar{t}$ spin-spin correlations as a function of the center-of-mass energy
and of the top quark scattering angle for arbitrary longitudinal polarization
of the electron/positron beam.


title:
Testing Anomalous Higgs Couplings in Triple Photon Production at the
  Tevatron Collider

abstract:
  We derive bounds on Higgs and gauge--boson anomalous interactions using the
CDF data for the process $p \bar{p} \to \gamma\gamma\gamma + X$. We use a
linearly realized $SU_L(2) \times U_Y(1)$ invariant effective Lagrangian to
describe the bosonic sector of the Standard Model, keeping the fermionic
couplings unchanged. All dimension--six operators that lead to anomalous Higgs
interactions involving $\gamma$ and $Z$ are considered. We also show the
sensitivity that can be achieved for these couplings at Fermilab Tevatron
upgrades.


title: Next-to-Leading QCD Corrections to B\to X_s \gamma in Supersymmetry

abstract:
  We compute the QCD next-to-leading order matching conditions of the
(chromo)-magnetic operators relevant for B\to X_s \gamma in supersymmetric
models with minimal flavour violation. The calculation is performed under the
assumption that the charginos and one stop are lighter than all other squarks
and the gluino. In the parameter region where a light charged Higgs boson is
consistent with measurements of BR(B\to X_s \gamma), we find sizeable
corrections to the Wilson coefficients. As a consequence, there is a
significant reduction of the stop-chargino mass region where the supersymmetric
contribution has a large destructive interference with the charged-Higgs boson
contribution.


title: Chirality, D-branes and gauge/string unification

abstract:
  We point out that models where gauge and charged matter fields live on the
world volume of D3 branes can provide a weak string coupling description of the
gauge coupling unification in the supersymmetric standard model at a scale of
order $10^{16}$ GeV. In the D3 brane picture, the string and unification scales
coincide, while the size of the extra dimensions is somewhat larger than the
string length. We then construct a quasirealistic "three generation" model with
D3 branes at orbifold fixed points. We point out that placing D3 branes at
different orbifold fixed points provides a geometric description of the
disconnected branches of moduli space and discuss the appropriate consistency
conditions. These disconnected branches allow for patterns of gauge symmetry
breaking inaccessible on the connected part of moduli space and can give rise
to "hidden" and "visible" sectors. Finally, we analyze supersymmetry breaking
on the brane world volume.


title:
Size of Penguin Pollution of the CKM CP Violating Phase in B-bar_s ->
  rho K_s

abstract:
  We use the perturbative QCD methods of Lepage and Brodsky to calculate the
rate for B-bar_s -> rho K_s, with an eye toward the CP violating unitarity
triangle angle gamma. We show that, although the penguins are large, there are
regions of the allowed parameter space of the Cabibbo-Kobayashi-Maskawa mixing
matrix wherein gamma is measurable in the sense that penguins change the value
of sin(2gamma) one would extract from the attendant time dependent asymmetry
measurement by less than 29 per cent, so that a 3sigma measurement of
sin(2gamma) as being different from 0 is allowed by the corresponding
theoretical uncertainty. This would establish CP violation in B_s decays. The
rates which we find tend to favor the type of luminosities now envisioned for
hadron-based B-factories.


title:
Mass signature of supernova $\nu_\mu$ and $\nu_\tau$ neutrinos in the
  Sudbury Neutrino Observatory

abstract:
  Core-collapse supernovae emit of order $10^{58}$ neutrinos and antineutrinos
of all flavors over several seconds, with average energies of 10--25 MeV. In
the Sudbury Neutrino Observatory (SNO), which begins operations this year,
neutrinos and antineutrinos of all flavors can be detected by reactions which
break up the deuteron. For a future Galactic supernova at a distance of 10 kpc,
several hundred events will be observed in SNO. The $\nu_\mu$ and $\nu_\tau$
neutrinos and antineutrinos are of particular interest, as a test of the
supernova mechanism. In addition, it is possible to measure or limit their
masses by their delay (determined from neutral-current events) relative to the
$\bar{\nu}_e$ neutrinos (determined from charged-current events). Numerical
results are presented for such a future supernova as seen in SNO. Under
reasonable assumptions, and in the presence of the expected counting
statistics, a $\nu_\mu$ or $\nu_\tau$ mass down to about 30 eV can be simply
and robustly determined. If zero delay is measured, then the mass limit is
independent of the distance $D$. At present, this seems to be the best
possibility for direct determination of a $\nu_\mu$ or $\nu_\tau$ mass within
the cosmologically interesting range. We also show how to separately study the
supernova and neutrino physics, and how changes in the assumed supernova
parameters would affect the mass sensitivity.


title: Collider Production of Spin 3/2 Particles

abstract:
  We consider the production of spin 3/2 quarks in hadron-hadron and
photon-photon colliders. The cross sections at LHC energy is large enough to
observe such exotic quarks up to a mass of a few TeV.


title: Torsion action and its possible observables

abstract:
  The methods of effective field theory are used to explore the theoretical and
phenomenological aspects of the torsion field. Spinor action coupled to
electromagnetic field and torsion possesses an additional softly broken gauge
symmetry. This symmetry enables one to derive the unique form of the torsion
action compatible with unitarity and renormalizability. It turns out that the
antisymmetric torsion field is equivalent to an massive axial vector field. The
introduction of scalars leads to serious problems which are revealed after the
calculation of the leading two-loop divergences. Thus the phenomenological
aspects of torsion may be studied only for the fermion-torsion systems. In this
part of the paper we obtain an upper bounds for the torsion parameters using
present experimental data on forward-backward Z-pole asymmetries, data on the
experimental limits on four-fermion contact interaction (LEP, HERA, SLAC, SLD,
CCFR) and also TEVATRON limits on the cross section of new gauge boson, which
could be produced as a resonance at high energy $p\bar{p}$ collisions. The
present experimental data enable one to put the limits on torsion parameters
for the various range of the torsion mass. We emphasize that for the torsion
mass of the order of the Planck mass no any independent theory for torsion is
possible, and one must directly use string theory.


title: Spin physics in deep inelastic scattering

abstract:
  The problem of our understanding of the spin structure of the nucleon has
been with us since the publication of the EMC measurements of the polarised
structure function of the proton in 1987. In this talk a brief history of the
subject is given followed by a review of the results presented in this workshop
and the progress made to date.


title: Squark Effects on Higgs Boson Production and Decay at the LHC

abstract:
  In the context of the Minimal Supersymmetric extension of the Standard Model,
I discuss the effects of relatively light top and bottom scalar quarks on the
main production mechanism of the lightest SUSY neutral Higgs boson $h$ at the
LHC, the gluon--gluon fusion mechanism $gg \to h$, and on the most promising
discovery channel, the two--photon decay mode $h \to \gamma \gamma$. In some
areas of the parameter space, the top and bottom squark contributions can
strongly reduce the production cross section times the branching ratio.


title: Final state photon production at LEP

abstract:
  We present a detailed study of photon production in hadronic events in
electron-positron annihilation at LEP energies. We show that estimates of the
inclusive photon spectrum using the quark-to-photon fragmentation function
determined using the ALEPH `photon' +~1 jet data agree well with the
observations of the OPAL collaboration. This agreement shows that the photon
fragmentation function determined in this way can be used for inclusive
observables. We also compare next-to-leading order and beyond leading logarithm
predictions obtained using the numerically resummed solutions of the
fragmentation function evolution equation of Bourhis, Fontannaz and Guillet and
Gl\"uck, Reya and Vogt with the data. Moreover, in order to check the general
behaviour of the fragmentation function, we consider an analytic series
expansion in the strong coupling. We find that the parameterizations are
inaccurate at large $x$ values. While the OPAL data is in broad agreement with
estimates based on any of these approaches, the ALEPH data prefers the resummed
BFG parameterization. Finally, there is some ambiguity as to whether the
fragmentation function is treated as ${\cal O}(\alpha)$ or ${\cal
O}(\alpha/\alpha_s)$. We show that at present this ambiguity affects mainly the
prediction for the `photon' +~1 jet rate at large $z$.


title:
Next-to-leading order calculation of four-jet observables in
  electron-positron annihilation

abstract:
  The production of four jets in electron-positron annihilation allows for
measuring the strong coupling and the underlying group structure of the strong
interaction simultaneously. This requires next-to-leading order perturbative
prediction for four-jet observables. In this paper we describe the theoretical
formalism of such a calculation with sufficient details. We use the dipole
method to construct a Monte Carlo program that can be used for calculating any
four-jet observable at the NLO accuracy. As new results, we present the NLO
prediction for the thrust minor, y_4 and C parameter (at C > 0.75) four-jet
shape variables and the four-jet rates with the Cambridge jet clustering
algorithm.


title:
Measuring the $\nu_{\mu}$ to $\bar{\nu_{\mu}}$ Ratio in a High
  Statistics Atmospheric Neutrino Experiment

abstract:
  By exploiting differences in muon lifetimes it is possible to distinguish
$\nu_{\mu}$ from $\bar{\nu_{\mu}}$ charged current interactions in underground
neutrino detectors. Such observations would be a useful tool in understanding
the source of the atmospheric neutrino anomaly.


title: A Brief History of J/Psi Suppression

abstract:
  Statistical QCD predicts that strongly interacting matter will become
deconfined at high temperatures and/or densities. The aim of high energy
nuclear collisions is to study the onset of deconfinement and the properties of
deconfined media in the laboratory. Hence it is essential to define an
unambiguous and experimentally viable probe for deconfinement. Twelve years
ago, T. Matsui and I proposed that \J~production should constitute such a probe
\cite{M&S}, and I want to sketch here rather briefly the evolution of this idea
in the light of subsequent experimental and theoretical work.


title: Unified Picture of DIS and Diffractive DIS

abstract:
  The QCD dipole picture allows to build an unified theoretical description
-based on BFKL dynamics- of the total and diffractive nucleon structure
functions. We use a four parameter fit to describe the 1994 H1 proton structure
function F2 data in the low x, moderate Q2 range. Without any additional
parameter, the gluon density and the longitudinal structure functions are
predicted. The diffractive dissociation processes are discussed within the same
framework, and a new 6 parameter fit of the 1994 H1 data is performed which
leads to a comprehensive description of F2D(3).


title:
Target Fragmentation in $pp$, $ep$ and $\gamma p$ Collisions at High
  Energies

abstract:
  We calculate target fragmentation in $p p \to n X$ and $\gamma p \to n X $
reactions in the meson cloud picture of the nucleon. The $p p \to n X$ reaction
is used to fix the $pn\pi^+$ form factor for three different models. We take
into account the possible destruction of the residual neutron by the
projectile. Using the form factor from the hadronic reaction we calculate
photoproduction and small $x_{Bj}$ electroproduction of forward neutrons at
HERA. Here the $q \bar q$ dipoles in the photon can rescatter on the residual
neutron. In photoproduction we observe slightly less absorption than in the
hadronic reaction. For deep inelastic events ($Q^2>10$ GeV$^2$) screening is
weaker but still present at large $Q^2$. The signature for this absorptive
rescattering is a shift of the $d\sigma/dE_n$ distribution to higher neutron
energies for photofragmentation.


title: Ultrahigh energy cosmic rays and supersymmetry

abstract:
  Recently, models proposing superheavy particles $X$ as source of ultrahigh
energy cosmic rays have attracted some interest. The $X$-particles are either
metastable relic particles from the early Universe or are released by
topological defects. In these models, the detected air-showers are produced by
primaries originating from the fragmentation of the $X$-particles. We present
the fragmentation spectrum of superheavy particles calculated in SUSY-QCD. Then
we discuss the status of the lightest supersymmetric particle as possible
ultrahigh energy primary.


title:
Extracting Top Quark CP Violating Dipole Couplings via $t\bar t\gamma$
  and $t\bar tZ$ Productions at the LHC

abstract:
  We propose to extract the electric and weak dipole moments of the top quark
via $t\bar t\gamma$ and $t\bar t Z$ productions at the CERN LHC. With the large
numbers of events available at the LHC, these dipole moments can be measured to
the accuracy of $10^{-18}e cm$.


title:
Pade-Improvement of QCD Running Coupling Constants, Running Masses,
  Higgs Decay Rates, and Scalar Channel Sum Rules

abstract:
  We discuss Pad\'e-improvement of known four-loop order results based upon an
asymptotic three-parameter error formula for Pad\'e-approximants. We derive an
explicit formula estimating the next-order coefficient $R_4$ from the previous
coefficients in a series $1+R_1 x + R_2x^2 + R_3x^3$. We show that such an
estimate is within 0.18% of the known five-loop order term in the O(1)
$\beta$-function, and within 10% of the known five-loop term in the O(1)
anomalous mass-dimension function $\gamma_m(g)$. We apply the same formula to
generate a [2$|$2] Pad\'e-summation of the QCD $\beta$-function and anomalous
mass dimension in order to demonstrate both the relative insensitivity of the
evolution of $\alpha_s(\mu)$ and the running quark masses to higher order
corrections, as well as a somewhat increased compatibility of the present
empirical range for $\alpha_s(m_\tau)$ with the range anticipated via evolution
from the present empirical range for $\alpha_s(M_z)$. For $3 \leq n_f \leq 6$
we demonstrate that positive zeros of any [2$|$2] Pad\'e-summation estimate of
the all-orders $\beta$-function which incorporates known two-, three-, and
four-loop contributions necessarily correspond to ultraviolet fixed points,
regardless of the unknown five-loop term. Pad\'e-improvement of higher-order
perturbative expressions is presented for the decay rates of the Higgs into two
gluons and into a $b \bar{b}$ pair, and is used to show the relative
insensitivity of these rates to higher order effects. However,
Pad\'e-improvement of the purely-perturbative component of scalar/pseudoscalar
current correlation functions is indicative of large theoretical uncertainties
in QCD sum rules for these channels, particularly if the continuum-threshold
parameter $s_0$ is near 1 GeV$^2$.


title: Branch Cuts Due to Finite-Temperature Quasiparticles

abstract:
  The branch points of individual thermal self-energy diagrams at
$k^{2}=4m^{2}, k^{2}=9m^{2},...$ are shown not to be branch points of the full
thermal self-energy. Branch points of the full theory are determined by the
complex, temperature-dependent energies of the quasiparticles, defined as the
pole location, $k_{0}={\cal E}(\vec{k})$, of the exact retarded propagator. The
full retarded self-energy is found to have branch points at $k_{0}=2{\cal
E}(\vec{k}/2)$ and $k_{0}=3{\cal E}(\vec{k}/3)$ as well as cuts in the
space-like region. The discontinuities across the branch cuts are complex. The
advanced self-energy is related by reflection to the retarded.


title:
Pade Approximants and the Fixed-Points of the three-flavour QCD
  beta-Function

abstract:
  The positive zeros of [2|1], [1|2] and the most general possible [2|2] Pade
approximants whose Maclaurin series reproduce the presently known terms in the
three-flavour QCD beta-function are all shown to correspond to ultraviolet
fixed points.


title:
Constraints on pre-big bang models for seeding large-scale anisotropy by
  massive Kalb-Ramond axions

abstract:
  We discuss the conditions under which pre-big bang models can fit the
observed large-scale anisotropy with a primordial spectrum of massive
(Kalb--Ramond) axion fluctuations.
  The primordial spectrum must be sufficiently flat at low frequency and
sufficiently steeper at high frequency. For a steep and/or long enough
high-frequency branch of the spectrum the bounds imposed by COBE's
normalization allow axion masses of the typical order for a
Peccei--Quinn--Weinberg--Wilczek axion. We provide a particular example in
which an appropriate axion spectrum is obtained from a class of backgrounds
satisfying the low-energy string cosmology equations.


title: Variations on Four-Neutrino Oscillations

abstract:
  We make a model-independent analysis of all available data that indicate
neutrino oscillations. Using probability diagrams, we confirm that a mass
spectrum with two nearly degenerate pairs of neutrinos separated by a mass gap
of $\simeq1$ eV is preferred over a spectrum with one mass eigenstate separated
from the others. We derive some new relations among the four-neutrino mixing
matrix elements. We design four-neutrino mass matrices with three active
neutrinos and one sterile neutrino that naturally incorporate maximal
oscillations of atmospheric $\nu_\mu$ and explain the solar neutrino and LSND
results. The models allow either a large or small angle MSW or vacuum
oscillation description of the solar neutrino deficit. The models predict (i)
oscillations of either $\nu_e \to \nu_\tau$ or $\nu_e \to\nu_s$ in
long-baseline experiments at $L/E \gg 1$ km/GeV, with amplitude determined by
the LSND oscillation amplitude and argument given by the atmospheric $\delta
m^2$, and (ii) the equality of the $\nu_e$ disappearance probability, the
$\nu_\mu$ disappearance probability, and the LSND $\nu_\mu\to\nu_e$ appearance
probability in short-baseline experiments.


title:
Gravitational waves constraints on post-inflationary phases stiffer than
  radiation

abstract:
  We point out that the existence of post-inflationary phases stiffer than
radiation leads to the production of stochastic gravitational waves (GW)
backgrounds whose logarithmic energy spectra (in critical units) are typically
"blue" at high frequencies. The maximal spectral slope (for present frequencies
larger than $10^{-16}$ Hz) is of order one and it is related to the maximal
sound velocity of the stiff plasma governing the evolution of the geometry. The
duration of the stiff phase is crucially determined by the backreaction of the
GW leaving the horizon during the de Sitter phase and re-entering during the
stiff phase. Therefore, the maximal (inflationary) curvature scale has to be
fine-tuned to a value smaller than the limits set by the large scale
measurements ($H_{dS}\laq 10^{-6}~M_{P}$) in order to a have a sufficiently
long stiff phase reaching an energy scale of the order of the $1~{\rm TeV}$ and
even lower if we want the stiff phase to touch the hadronic era (corresponding
to $T_{had}\sim 140~{\rm MeV}$). By looking more positively at our exercise we
see that, if an inflationary phase is followed by a stiff phase, there exist an
appealing possibility of "graviton reheating" whose effective temperature can
be generally quite low.


title: Low-Energy Supersymmetry at Future Colliders

abstract:
  We classify the variety of low-energy supersymmetric signatures that can be
probed at future colliders. We focus on phenomena associated with the minimal
supersymmetric extension of the Standard Model. The structure of the
supersymmetry-breaking introduces additional model assumptions. The approaches
considered here are supergravity-mediated and gauge-mediated
supersymmetry-breaking. Alternative phenomenologies arising in non-minimal
and/or R-parity-violating approaches are also briefly examined.


title: Probing the MSSM Higgs Sector at an e-e- Collider

abstract:
  The theoretical structure of the Higgs sector of the Minimal Supersymmetric
Standard Model (MSSM) is briefly described. An outline of Higgs phenomenology
at future lepton colliders is presented, and some opportunities for probing the
physics of the MSSM Higgs sector at an e-e- collider are considered.


title:
Single Top Quark at Future Hadron Colliders. Complete Signal and
  Background Study

abstract:
  We perform a detail theoretical study including decays and jet fragmentation
of all the important modes of the single top quark production and all basic
background processes at the upgraded Tevatron and LHC colliders. Special
attention was paid to the complete tree level calculation of the QCD fake
background which was not considered in the previous studies. Analysis of the
various kinematical distributions for the signal and backgrounds allowed to
work out a set of cuts for an efficient background suppression and extraction
of the signal. It was shown that the signal to background ratio after optimized
cuts could reach about 0.4 at the Tevatron and 1 at the LHC. The remaining
after cuts rate of the signal at the LHC for the $lepton+jets $ signature is
expected to be about 6.1 pb and will be enough to study the single top physics
even during the LHC operation at a low luminosity.


title: Studies of structure functions at a low-energy facility

abstract:
  We discuss the studies on structure functions at the possible future RCNP
facility. At this stage, an electron-proton or proton-proton collider with
sqrt{s}=5 - 10 GeV is considered. We explain large-x physics, nuclear
modification of sea-quark and gluon distributions, and tensor spin structure
function as the interesting topics at the facility. The large-x parton
distributions are important for finding new physics beyond QCD in anomalous
events such as the CDF jet data. The nuclear parton distributions are valuable
in detecting a quark-gluon signature in heavy-ion reactions. The tensor
structure function b_1 is a new field of high-energy spin physics. Considering
these physics possibilities, we believe that the possible RCNP facility is
important for the hadron-structure community.


title: Particle Mass Limits in Minimal and Nonminimal Supersymmetric Models

abstract:
  A review of the Higgs and neutralino sectors of supersymmetric models is
presented. This includes the upper limit on the mass of the lightest Higgs
boson in the Minimal Supersymmetric Standard Model, as well as models based on
the Standard Model gauge group $SU(2)_L \times U(1)_Y$ with extended Higgs
sectors. We then discuss the Higgs sector of left-right supersymmetric models,
which conserve R-parity as a consequence of gauge invariance, and present a
calculable upper bound on the mass of the lightest Higgs boson in these models.
We also discuss the neutralino sector of general supersymmetric models based on
the SM gauge group. We show that, as a consequence of gauge coupling
unification, an upper bound on the mass of the lightest neutralino as a
function of the gluino mass can be obtained.


title: Stability of large scale chromomagnetic fields in the early universe

abstract:
  It is well known that Yang-Mills theory in vacuum has a perturbative
instability to spontaneously form a large scale magnetic field (the Savvidy
mechanism) and that a constant field is unstable so that a possible ground
state has to be inhomogenous over the non-perturbative scale Lambda (the
Copenhagen vacuum). We argue that this spontaneous instability does not occur
at high temperature when the induced field strength gB ~ Lambda^2 is much
weaker than the magnetic mass squared (g^2T)^2. At high temperature
oscillations of gauge fields acquire a thermal mass M ~ gT and we show that
this mass stabilizes a magnetic field which is constant over length scales
shorter than the magnetic screening length (g^2T)^{-1}. We therefore conclude
that there is no indication for any spontaneous generation of weak non-abelian
magnetic fields in the early universe.


title: Pseudoscalar decay constants at large N_c

abstract:
  In the large N_c limit, the variables required to analyze the low energy
structure of QCD in the framework of an effective field theory necessarily
include the degrees of freedom of the eta'. We evaluate the decay constants of
the pseudoscalar nonet to one loop within this extended framework and show
that, as a consequence of the anomalous dimension of the singlet axial current,
some of the effective coupling constants depend on the running scale of QCD.
The calculation relies on a simultaneous expansion in powers of momenta, quark
masses and 1/N_c.
  Talk given at the Workshop on Nonperturbative Methods in Quantum Field
Theory, NITP/CSSM, University of Adelaide, Australia, Feb. 1998.


title:
Three-body decays of Higgs bosons at LEP2 and application to a hidden
  fermiophobic Higgs

abstract:
  We study the decays of Higgs bosons to a lighter Higgs boson and a virtual
gauge boson in the context of the non-supersymmetric Two-Higgs-Doublet-Model
(2HDM). We consider the phenomenological impact at LEP2 and find that such
decays, when open, may be dominant in regions of parameter space and thus
affect current Higgs boson search techniques. Three-body decays would be a way
of producing light neutral Higgs bosons which have so far escaped detection at
LEP due to suppressed couplings to the $Z$, and are of particular importance in
the 2HDM (Model I) which allows both a light fermiophobic Higgs and a light
charged scalar.


title: Effective Field Theory of QED Vacuum Fluctuations

abstract: Plenary talk at PASCOS-98, Boston, Massachusetts, USA, March 22-29, 1998.


title: Solar-neutrino oscillations and third-flavour admixture

abstract:
  With one \Delta m^2 of the appropriate order of magnitude to solve the
atmospheric neutrino problem, we study the resulting three-generation
vacuum-oscillation fit to the solar neutrino flux. An explanation of the
atmospheric neutrino composition in terms of pure \nu_\mu \to \nu_\tau
oscillations is easily compatible with the well-known two-flavour oscillation
solution for solar neutrinos. The allowed parameter region in the
\sin^2(2\theta_{12})--\Delta m^2 plane changes little with increasing values of
the mixing element U_{e3}, provided this is less than about 0.4. We find that
the threefold maximal mixing is disfavoured.


title:
Tests of Factorization in Diffractive Charm Production and Double
  Pomeron Exchange

abstract:
  We present predictions for the diffractive production of heavy quarks in
deep-inelastic scattering and hadron-hadron collisions and for double
diffractive dijet production in hadron-hadron collisions. With the assumption
of hard scattering factorization, the predictions are made using diffractive
parton densities that we have previously fitted to HERA data. Comparisons of
our predictions with preliminary data from HERA and the Tevatron indicate that
factorization is obeyed in diffractive DIS but fails in hadron-induced
processes.


title: Isolated and non-isolated photon rates at LEP

abstract:
  We present the results of the calculation of the `photon' +~1 jet rate at
${\cal O}(\alpha \alpha_{s})$ for LEP energies. By comparing these results with
the data from the ALEPH Collaboration we make a next-to-leading order
determination of the quark-to-photon fragmentation function $D_{q\to
\gamma}(z,\mu_{F})$ at ${\cal O}(\alpha \alpha_{s})$. The predictions obtained
using this fragmentation function for the isolated rate, defined as the
`photon' +~1 jet rate for $z>0.95$, are found in good agreement with the ALEPH
data. The next-to-leading order corrections are moderate demonstrating the
perturbative stability of this particular isolated photon definition. We have
also computed the inclusive photon energy distribution and found good agreement
with the OPAL data.


title: Odd C-P contributions to diffractive processes

abstract:
  We investigate contributions to diffractive scattering, which are odd under
C- and P-parity. Comparison of p-$\bar p$ and p-p scattering indicates that
these odderon contributions are very small and we show how a diquark clustering
in the proton can explain this effect. A good probe for the odderon exchange is
the photo- and electroproduction of pseudo-scalar mesons. We concentrate on the
pi^0 and show that the quasi elastic pi^0-production is again strongly
suppressed for a diquark structure of the proton whereas the cross sections for
diffractive proton dissociation are larger by orders of magnitude and rather
independent of the proton structure.


title: Classical fields as coherent states and diffusion equations

abstract:
  We present a derivation of the effect of the classical field configuration to
the diffusion equations. Using the formalism of the thermo field dynamics we
propose a systematic and consistent way to treat the classical background and
to calculate it's effect at any order of the perturbation theory. We treat the
classical field in genuine quantum field theory formalism as a coherent state
and show how the propagators and self energies are altered in this case.


title: Small x: Two Pomerons!

abstract:
  Regge theory provides a very simple and economical description of data for
(i) the proton structure function with x<0.07 and all available Q^2 values,
(ii) the charm structure function, and (iii) gamma p --> J/psi p. The data are
all in agreement with the assumption that there is a second pomeron, with
intercept about 1.4 . They suggest also that the contribution from the soft
pomeron is higher twist.
  This means that there is an urgent need to make perturbative evolution
compatible with Regge theory at small and not-so-small x, and to reassess the
magnitude of higher-twist contributions at quite small x.


title: On positivity of parton distributions

abstract:
  We discuss the bounds on polarized parton distributions which follow from
their definition in terms of cross section asymmetries. We spell out how the
bounds obtained in the naive parton model can be derived within perturbative
QCD at leading order when all quark and gluon distributions are defined in
terms of suitable physical processes. We specify a convenient physical
definition for the polarized and unpolarized gluon distributions in terms of
Higgs production from gluon fusion. We show that these bounds are modified by
subleading corrections, and we determine them up to NLO. We examine the ensuing
phenomenological implications, in particular in view of the determination of
the polarized gluon distribution.


title: A One-Scale Model of Dynamical Supersymmetry Breaking

abstract:
  A model of gauge-mediated supersymmetry breaking is constructed in which the
low-energy physics depends on a single dynamical scale. Strong coupling
dynamics of gauge theories plays an important role, in particular through its
effects on beta functions and through confinement. The model does not have
distinct messenger and supersymmetry-breaking sectors. The scale of
supersymmetry breaking is of order 10-100 \TeV, implying that the decay of the
next-to-lightest superpartner into the gravitino is prompt. Superoblique
corrections are enhanced. A Dirac fermion and one complex scalar, in a 10 or
\bar{10} of (global) SU(5), are predicted to be relatively light and to satisfy
certain mass relations with the standard model squarks and sleptons.


title:
New CP observables in B0(t) -> hyperon + antihyperon from parity
  violation in the sequential decay

abstract:
  We consider the decay B0(t) -> hyperon + antihyperon, followed by hyperon
weak decay. We show that parity violation in the latter allows to reach new CP
observables: not only Im(lambda_f) but also Re(lambda_f) can be measured. In
the decay B0_d(t) -> Lambda LambdaBar (BR ~ 10-6), Lambda -> p pi- these
observables reduce to sin(2alpha) and cos(2alpha) in the small Penguin limit,
the latter solving the discrete ambiguity alpha -> pi/2 -alpha. For beta one
could consider the Cabibbo suppressed mode B0_d(t) -> Lambda_c Lambda_cBar (BR
\~ 10-4), Lambda_c -> Lambda pi+, p K0bar, ... (with BR ~ 10-2). The pure
Penguin modes B0_s(t)->Sigma-Sigma-Bar, Xi-Xi-Bar, Omega-Omega-Bar (BR ~ 10-7)
can be useful in the search of CP violation beyond the Standard Model. Because
of the small total rates, the study of these modes could only be done in future
high statistics experiments. Also, in the most interesting case Lambda
LambdaBar the time dependence of the asymmetry can be difficult to reconstruct.
On the other hand, we show that B_d mesons, being a coherent source of Lambda
LambdaBar, is useful to look for CP violation in Lambda decay. We also discuss
B0_d(t) -> J/Psi K*0 -> l+ l- K_S pi0 where the secondary decays conserve
parity, and angular correlations allow to determine terms of the form
cos(delta)cos(2beta), delta being a strong phase. This phase has been measured
by CLEO, but we point out that a discrete ambiguity prevents to determine
sign(cos(2beta)). However, if one assumes small strong phases, like in
factorization and as supported by CLEO data, one could have information on
sign(cos(2beta)). Similar remarks can be done for cos(2alpha) in the decay
B_d0(t) -> rho rho -> 4pi.


title: Rescattering Information from $B \to K \bar K$ Decays

abstract:
  Rescattering effects can modify the dependence on the weak phase $\gamma =
-{\rm Arg}(V^*_{ub}V_{ud}/V^*_{cb} V_{cd})$ of the ratio of rates for $B^{\pm}
\to K \pi^\pm$ and $B \to K^\pm \pi^\mp$. A test for these effects based on the
processes $B^\pm \to K^\pm K$ has been suggested. It is pointed out that the
rates for the processes $B \to K^+ K^-$, which are expected to be {\it
dominated} by rescattering and for which considerably better experimental
bounds exist, are likely to provide a more stringent constraint on these
effects.


title: Pion-Pion Scattering in Two Dimensions

abstract:
  Massive two-flavor QED_2 is known to have many similarities to the two-flavor
QCD_4. Here we compare the \pi-\pi scattering amplitudes (actually an analog
process in QED_2) of the two theories. The QED_2 amplitude is computed from the
bosonized version of the model while the QCD_4 amplitude is computed from an
effective low energy chiral Lagrangian. A number of interesting features are
noted. For example, the contribution of the two-dimensional Wess-Zumino-Witten
(WZW) term in QED_2 is structurally identical to the vector meson exchange
contribution in QCD_4. Also it is shown that the QED_2 amplitude computed at
tree level is a reasonable approximation to the known exact strong coupling
solution.


title: k-Factorization and Impact Factors at Next-to-leading Level

abstract:
  We further analyse,at next-to-leading log(s) level,the form of
k-factorization and the definition of impact factors previously proposed by one
of us,and we generalize them to the case of hard colourless probes. We then
calculate the finite one-loop corrections to quark and gluon impact factors and
we find them universal,and given by the same K factor which occurs in the soft
timelike splitting functions.


title:
Measuring the Trilinear Couplings of MSSM Neutral Higgs Bosons at
  High-Energy e^+e^- Colliders

abstract:
  We present a detailed analysis of multiple production of the lightest CP-even
Higgs boson (h) of the Minimal Supersymmetric Standard Model (MSSM) at
high-energy e^+ e^- colliders. We consider the production of the heavier
CP-even Higgs boson (H) via Higgs-strahlung e^+e^- \to ZH, in association with
the CP-odd Higgs boson (A) in e^+e^- \to AH, or via the fusion mechanism e^+e^-
\to \nu_e \bar\nu_e H, with H subsequently decaying through H \to hh, thereby
resulting in a pair of lighter Higgs bosons (h) in the final state. These
processes can enable one to measure the trilinear Higgs couplings \lambda_{Hhh}
and \lambda_{hhh}, which can be used to theoretically reconstruct the Higgs
potential. We delineate the regions of the MSSM parameter space in which these
trilinear Higgs couplings could be measured at a future e^+ e^- collider. In
our calculations, we include in detail the radiative corrections to the Higgs
sector of the MSSM, especially the mixing in the squark sector.


title:
Diffractive photo- and leptoproduction of vector mesons $\rho$, $\rho'$
  and $\rho''$

abstract:
  We calculate diffractive photo- and leptoproduction of $\rho$-, $\rho'$- and
$\rho''$-mesons. The incoming photon dissociates into a $q\bar{q}$-dipole which
scatters on the nucleon and transforms into a vector meson state. The
scattering amplitude is calculated in non-perturbative QCD with the model of
the stochastic vacuum. Assuming that the physical $\rho'$- and $\rho''$-mesons
are mixed states of an active 2S-excitation and some residual hybrid state
which cannot be produced diffractively in lowest order QCD, we obtain good
agreement with the data, especially the markedly different spectrum in the
$\pi^+\pi^-$-invariant mass for photoproduction and $e^+e^-$-annihilation.


title: Generalized Vector Dominance and Low-x Proton Structure

abstract:
  The low-x HERA data on inelastic lepton-proton scattering are interpreted in
terms of Generalized Vector Dominance.


title:
Supersymmetric Electroweak Phase Transition: Baryogenesis versus
  Experimental Constraints

abstract:
  We use the two loop effective potential to study the first order electroweak
phase transition in the minimial supersymmetric standard model. A global search
of the parameter space is made to identify parameters compatible with
electroweak baryogenesis. We improve on previous such studies by fully
incorporating squark and Higgs boson mixing, by using the latest experimental
constraints, and by computing the latent heat and the sphaleron rate. We find
the constraints tan beta > 2.1, top squark mass < 172 GeV, and Higgs mass < 107
GeV (becoming more or less restrictive if the heavy stop has mass less than or
greater than 1 TeV). We also find that the change in tan beta in the bubble
wall is rarely greater than 0.001, which severely constrains the mechanism of
baryogenesis.


title:
Relations among polarized and unpolarized splitting functions beyond
  leading order

abstract:
  The role of various symmetries in the evaluation of splitting functions and
coefficient functions is discussed. The scale invariance in hard processes is
known to be a guiding tool to understand the dynamics. We discuss the
constraints on splitting functions coming from various symmetries such as
scale, conformal and supersymmetry. We also discuss the Drell-Levy-Yan relation
among splitting and coefficient functions in various schemes. The relations
coming from conformal symmetry are also presented.


title: Single Transverse-Spin Asymmetries in Hadronic Pion Production

abstract:
  We analyze single transverse-spin asymmetries for hadronic pion production at
large transverse momenta using QCD factorization. In the large $x_F$ region,
leading contributions to the asymmetries are naturally produced by twist-3
parton correlation functions that couple quark fields and gluon field
strengths. With a simple model for these matrix elements, leading-order
asymmetries calculated from QCD are consistent with data on pion production
from Fermilab, and can be used to predict single-spin asymmetries at RHIC. We
argue that our perturbative calculation for the asymmetries is relevant to pion
transverse momenta as low as a few GeV.


title: On the Gluon Regge Trajectory in $O(\alpha_s^2)$

abstract:
  We recalculate the gluon Regge trajectory in next-to-leading order to clarify
a discrepancy between two results in the literature on the constant part. We
confirm the result obtained by Fadin et al.~\cite{FFK}. The effects on the
anomalous dimension and on the $s^{\omega}$ behavior of inclusive cross
sections are also discussed.


title:
Exact Light-Cone Wavefunction Representation of Matrix Elements of
  Electroweak Current

abstract:
  The matrix elements of electroweak currents which occur in exclusive decays
of heavy hadrons are evaluated in the nonperturbative light-cone Fock
representration. In general, each semileptonic exclusive decay amplitude
receives two contributions, a diagonal $\Delta n = 0$ parton-number-conserving
amplitude and a $\Delta n = -2$ contribution in which a quark and an antiquark
from the initial hadron Fock state annihilate to the leptonic current. The
general formalism can be used as a basis for systematic approximations to heavy
hadron decay amplitudes such as hard perturbative QCD contributions. We
illustrate the general formalism using a simple perturbative model of composite
hadrons. Our analysis demonstrates the occurence of "zero-mode" endpoint
contributions to matrix elements of the "bad" $j^-$ currents in the Drell-Yan
frame when $q^+ \to 0$.


title: $B\to\tau\mu (X)$ decays in SUSY models without R-parity

abstract:
  Being strictly forbidden in the standard model, experimental detection of the
lepton flavor violating decays $B(\bar B)\to\tau^+\mu^-$ and $b(\bar b)\to
X\tau^+\mu^-$ would constitute an unmistakable indication of new physics. We
study these decays in supersymmetric models without R-parity and without lepton
number. In order to derive order of magnitude predictions for the branching
ratios, we assume a horizontal U(1) symmetry with horizontal charges chosen to
explain the magnitude of fermion masses and quark mixing angles. We find that
the branching ratios for decays with a $\tau\mu$ pair in the final state are
not particularly suppressed with respect to the lepton flavor conserving
channels. In general in these models ${\rm B}[b\to\mu^+\mu^-(X)]\lsim {\rm
B}[b(\bar b)\to\tau^+\mu^-(X)] \lsim {\rm B}[b\to\tau^+\tau^-(X)]$. While in
some cases the rates for final states $\tau^+\tau^-$ can be up to one order of
magnitude larger than the lepton flavor violating channel, due to better
efficiencies for muon detection and to the absence of standard model
contributions, decays into $\tau\mu$ final states appear to be better suited to
reveal this kind of new physics.


title: Triple Gauge Boson Couplings in Rare B and K Decays

abstract:
  We examine the sensitivity of flavor changing neutral current (FCNC)
processes to anomalous triple gauge boson couplings. We show that in the
non-linear realization of the electroweak symmetry breaking sector these
processes are very sensitive to two CP conserving anomalous couplings. A clean
separation of their effects is possible in the next round of experiments
probing $b\to s\gamma$ and $b\to s\ell^+\ell^-$ processes, as well as kaon
decays such as $K^+\to\pi^+\nu\bar\nu$. The obtained sensitivity is found to be
competitive with that of direct measurements at high energy colliders. In
particular, for one of the $WWZ$ couplings the one-loop FCNC effects are
enhanced by a logarithmic dependence on the scale of new physics. We also
explore the potential signals of CP violating anomalous triple gauge boson
couplings in rare $B$ decays.


title: A Heavy Gluino as the Lightest Supersymmetric Particle

abstract:
  We consider the possibility that the lightest supersymmetric particle is a
heavy gluino. After discussing models in which this is the case, we demonstrate
that the gluino-LSP could evade cosmological and other constraints by virtue of
having a very small relic density. We then consider how neutral and charged
hadrons containing a gluino will behave in a detector, demonstrating that there
is generally substantial apparent missing momentum associated with a produced
gluino-LSP. We next investigate limits on a (heavy) gluino-LSP deriving from
LEP, LEP2 and RunI Tevatron experimental searches for excess events in the jets
plus missing momentum channel and for stable heavily-ionizing charged
particles. The range of gluino mass that can be excluded depends upon the path
length of the gluino in the detector, the amount of energy it deposits in each
hadronic collision, and the probability for the gluino to fragment to a
pseudo-stable charged hadron after a given hadronic collision. We explore how
the range of excluded gluino mass depends upon these ingredients, concluding
that for non-extreme cases the range $3\gev\lsim\mgl\lsim 130-150\gev$ can be
excluded at 95% CL based on currently available OPAL and CDF analyses. We find
that RunII at the Tevatron can extend the excluded region (or discover the
gluino) up to $\mgl\sim 160-180\gev$. For completeness, we also analyze the
case where the gluino is the NLSP (as possible in gauge-mediated supersymmetry
breaking) decaying via gluino -> g + gravitino. We find that the Tevatron RunI
data excludes $\mgl\leq 240$ GeV. Finally, we discuss application of the
procedures developed for the heavy gluino-LSP to searches for other stable
strongly interacting particles, such as a stable heavy quark.