title: Dijet Production at Hadron--Hadron Colliders in the BFKL Approach

abstract:
  The production in high-energy hadron collisions of a pair of jets with large
rapidity separation is studied in an improved BFKL formalism. By recasting the
analytic solution of the BFKL equation as an explicit order-by-order sum over
emitted gluons, the effects of phase space constraints and the running coupling
are studied. Particular attention is paid to the azimuthal angle decorrelation
of the jet pair. The inclusion of sub-leading effects significantly improves
the agreement between the theoretical predictions and recent preliminary
measurements from the Dzero collaboration.


title: Pion Production from Baked-Alaska Disoriented Chiral Condensate

abstract:
  We study the various stages of the evolution of chiral condensates
disoriented via the ``baked-alaska'' mechanism, in which the condensates are
described as the products of external sources localized on the light cone. Our
analysis is based on the classical equations of motion of either the linear or
the nonlinear sigma model. We use the associated framework of coherent states
and, especially, their source functions to make the connection to the
distribution functions for the produced particles. We also compare our
classical approach with a mean-field calculation which includes a certain class
of quantum corrections.


title:
Magnetic moments of the SU(3) decuplet baryons in the chiral
  quark-soliton model

abstract:
  Magnetic moments of baryons are studied within the chiral quark soliton model
with special emphasis on the decuplet of baryons. The model is used to identify
all symmetry breaking terms proportional to $m_{\rm s}$. Sum rules for the
magnetic moments are derived. A ``model-independent'' analysis of the symmetry
breaking terms is performed and finally model calculations are presented, which
show the importance of the rotational $1/N_{\rm c}$ corrections for cranking of
the soliton.


title:
Disentangling Non-Standard Model T-Violating Sources in Exclusive
  Semileptonic B Decays

abstract:
  Measurements of the polarization of the lepton and D* in the exclusive
semileptonic B decays, B to D l nu and B to D* l nu, can be used to separate
and identify the non-standard model sources of T violation. These T-odd
effects, estimated in both supersymmetric and non-supersymmetric models, could
be within the reach of the planned B factories.


title: Evolution of Superconducting String Currents

abstract:
  We extend the quantititative string evolution model of Martins and Shellard
to superconducting strings by introducing a simple toy model for the evolution
of the currents. This is based on the dynamics of a `superconducting
correlation length'. We derive the relevant evolution equations and discuss the
importance of plasma effects. Some consequences of our results are also
suggested.


title:
Next-to-next-to-leading order QCD analysis of the revised CCFR data for
  xF_3 structure function and the higher twist contributions

abstract:
  We present the results of the next-to-next-to-leading order QCD analysis of
the recently revised experimental data of the CCFR collaboration for the $xF_3$
structure function using the Jacobi polynomial expansion method. The effects of
the higher twist contributions are included into the fits following the
infrared renormalon motivated model. The special attention is paid to the
checks of the predictive abilities of the infrared renormalon model and to the
independent extraction of the $x$-shape of the twist-4 contributions to the
$xF_3$ structure function in the process of the leading order, next-to-leading
order and next-to-next-to-leading order fits of the revised CCFR data. We
stress that at the next-to-next-to-leading order the results for
$\alpha_s(M_Z)$ turn out to be almost nonsensitive to the higher-twist terms.
We obtain the following result $\alpha_s(M_Z)^{NNLO}=0.117 \pm 0.002(stat) \pm
0.005 (syst)\pm 0.003 (theory)$. The comparison of the outcomes of our
next-to-leading order and next-to-next-to-leading order analysis indicate that
the theoretical QCD uncertainties were underestimated in the process of the
next-to-leading order determination of $\alpha_s(M_Z)$, made recently by the
CCFR collaboration itself.


title:
Mass Matrix Ansatz for Degenerate Neutrinos Consistent with Solar and
  Atmospheric neutrino Data

abstract:
  We suggest mass matrices for neutrinos and charged leptons that can explain
solar and atmospheric neutrino data. The resulting flavor mixing matrix
$V_{\nu}$ has a property that $(V_{\nu})_{13}=0$, thus making $\nu_e
\leftrightarrow \nu_{\mu}$ and $\nu_{\mu} \leftrightarrow \nu_{\tau}$
oscillations to be effectively a two-channel problem. Phenomenological
consequences of the lepton mass matrix ansatze are consistent with the current
data on various type of neutrino oscillation experiments except the LSND
measurement. %and that three neutrinos are almost degenerate in mass. Three
neutrinos, being almost degenerate with $\sum | m_{\nu_i} | \lesssim 1 $ eV,
can be a part of hot dark matter without any conflict with the constraint from
neutrinoless double beta decay experiments. The $\nu_{\mu} \leftrightarrow
\nu_{\tau}$ oscillation, $\sin^2{2\theta_{\mu \tau}}$, is predicted to be
0.86-0.97 with $\Delta m^2_{\mu \tau}\simeq 2 \times 10^{-3} {eV}^2$, which is
consistent with the atmospheric neutrino data and can be tested further at the
planned MINOS and K2K experiments searching for $\nu_{\mu} \to \nu_{\tau}$
oscillation.


title: W + 1 jet to W + 0 jet Ratio at the Tevatron: A Hint of New Physics?

abstract:
  We interpret the reported disagreement between the measured ratio, R_{10}, of
the W + 1 jet cross-section to the W + 0 jet cross-section at the Tevatron and
the Standard Model (SM) prediction, as the effect of interactions mediated by a
colour-octet analogue of the W-boson, the W_8. The presence of a W_8 with mass
O(300) GeV, and with couplings to quarks and gluons of the order of electroweak
strength, allows the observations of the D0 collaboration to be reproduced
quite accurately. Such an interaction is not in contradiction with the present
CDF data on W+ W- or dijet production, though higher luminosities may reveal
measurable effects.


title: Axial Anomaly Low Energy Tests and Instanton Vacuum Models

abstract:
  A low energy theorem concerning a matrix element of the QCD axial anomaly
between vacuum and two-photons states is tested against different instanton
models. In the chiral limit the theorem is fulfilled by the Diakonov&Petrov
model, whereas it is violated by single-instanton approximations. Beyond the
chiral limit the theorem, and two relations established for other matrix
elements of the QCD axial anomaly between vacuum and meson states, result to be
violated also by the Diakonov&Petrov model.


title: Neutralino Annihilation into Two Photons

abstract:
  We compute the annihilation cross-section of two neutralinos at rest into two
photons, which is of importance for the indirect detection of neutralino dark
matter in the galactic halo through a quasi-monochromatic gamma-ray line. We
include all diagrams to one-loop level in the minimal supersymmetric extension
of the standard model. We use the helicity formalism, the background-field
gauge, and an efficient loop-integral reduction method. We confirm the result
recently obtained by Bergstrom and Ullio in a different gauge, which disagrees
with other published calculations.


title:
Weak Decay Process of $B \to \rho \ell \bar\nu_\ell$: A Varying External
  Field Approach in QCD Sum Rules

abstract:
  A varying external field approach in QCD sum rules is formulated in a
systematic way to treat the weak decay form factors and their $q^2$ dependence
in the process of $B \to \rho \ell \bar\nu_\ell$. From the form factor sum
rules, we can also obtain the mass sum rules for B and $\rho$ mesons, which can
help us determine the reliable Borel windows in studying the relevant form
factor sum rules. In this way, we thus demonstrate that some QCD sum rule
calculations in the literature are less reliable. We also include induced
condensate contributions, which have been ignored, into the relevant sum rules.
We obtain the ratios $\Gamma(\bar B^0\to\rho^+ e^- \bar\nu_e)$/ $\Gamma(\bar
B^0\to\pi^+ e^- \bar\nu_e)$$\approx$ 0.94 and $\Gamma(\bar B^0\to\rho^+ \tau^-
\bar\nu_\tau)$/ $\Gamma(\bar B^0\to\pi^+ \tau^- \bar\nu_\tau)$ $\approx$ 1.15.
We apply this approach to re-examine the case of the $D$ meson decay.


title:
Extracting Supersymmetry-Breaking Effects from Wave-Function
  Renormalization

abstract:
  We show that in theories in which supersymmetry breaking is communicated by
renormalizable perturbative interactions, it is possible to extract the soft
terms for the observable fields from wave-function renormalization. Therefore
all the information about soft terms can be obtained from anomalous dimensions
and beta functions, with no need to further compute any Feynman diagram. This
method greatly simplifies calculations which are rather involved if performed
in terms of component fields. For illustrative purposes we reproduce known
results of theories with gauge-mediated supersymmetry breaking. We then use our
method to obtain new results of phenomenological importance. We calculate the
next-to-leading correction to the Higgs mass parameters, the two-loop soft
terms induced by messenger-matter superpotential couplings, and the soft terms
generated by messengers belonging to vector supermultiplets.


title:
Chi_1 and Polarisation Asymmetries for Quarkonia at High Orders in
  Non-relativistic QCD

abstract:
  We study doubly polarised asymmetries of c-cbar and b-bbar mesons in hadro-
and photo-production at low transverse momentum in non-relativistic QCD to high
orders in the relative velocity of the pair, v. We give the complete set of
expressions required for the asymmetries up to order v^9. The asymmetries in
the production of eta_{c,b} states are a stable measure of the polarised gluon
densities. The asymmetries for chi_{c,b}, J/psi, psi', and the various Upsilon
states are stringent tests of the NRQCD scaling relations.


title: Low-Energy Constraints on New Physics Revisited

abstract:
  It is possible to place constraints on non-Standard-Model gauge-boson
self-couplings and other new physics by studying their one-loop contributions
to precisely measured observables. We extend previous analyses which constrain
such nonstandard couplings, and we present the results in a compact and
transparent form. Particular attention is given to comparing results for the
light-Higgs scenario, where nonstandard effects are parameterized by an
effective Lagrangian with a linear realization of the electroweak symmetry
breaking sector, and the heavy-Higgs/strongly interacting scenario, described
by the electroweak chiral Lagrangian. The constraints on nonstandard
gauge-boson self-couplings which are obtained from a global analysis of
low-energy data and LEP/SLC measurements on the Z pole are updated and improved
from previous studies. Replaced version: tables and figures of Section VIb
recalculated. There were roundoff problems, especially in Fig. 8. Text
unchanged.


title: Implications of the Glueball-qqbar filter on the 1++ nonet

abstract:
  The application of our glueball-qqbar filter to the centrally produced
KKbarpi system shows that the f1(1285) and f1(1420) have the same behaviour;
namely consistent with the f1(1420) being the partner to the f1(1285) in the
3P1 nonet of axial mesons. We determine a flavour singlet-octet mixing angle of
approximately 50 degrees for this nonet and highlight that the existence of the
supposed f1(1510) needs confirmation.


title:
Gauge-Invariant Renormalization Group at Finite Temperature and Debye
  Screening

abstract:
  I describe an application of Wilson Renormalization group to the real time
formalism of finite temperature field theory. The approach has two nice
features: 1) the RG flow equations describe non-perturbatively the effect of
thermal fluctuations only, and, 2) the flow is gauge invariant. I then describe
the application of the method to the study of the gluon self-energy in SU(N),
and present results for the computation of the Debye and magnetic screening
masses.


title: A general approach to jet cross sections in QCD

abstract:
  I illustrate a general formalism based upon the subtraction method for the
calculation of next-to-leading order QCD cross sections for any number of jets
in any type of hard collisions. I discuss the implementation of this formalism
in a numerical program which generates partonic kinematical configurations with
an appropriate weight, thus allowing the definition of arbitrary jet algorithms
and cuts matching the experimental setup at the last step of the computation. I
present results obtained with computer codes which calculate one-jet and
two-jet inclusive quantities in photon-hadron and hadron-hadron collisions.


title:
Three flavor neutrino oscillation analysis of the kamiokande atmospheric
  neutrino data

abstract:
  Using the published Kamiokande binned data for sub-GeV and multi-GeV
atmospheric neutrinos, we have searched for the optimum set of three flavor
neutrino oscillation parameters within the constraints of reactor experiments.
It is found that chi^2 is minimized for (Delta m_{21}^2, Delta m_{32}^2,
theta_{12}, theta_{13}, theta_{23}) = (7.4x10^{-1} eV^2, 2.6x 10^{-2} eV^2, 2
deg, 3 deg, 45 deg) and (2.6x 10^{-2} eV^2, 7.4x10^{-1} eV^2, 0 deg, 87 deg, 46
deg) with chi_{min}^2 = 87.8 (76%CL). The sets of parameters which are
suggested by the two flavor analysis turn out to be close to the minimum
(0.2sigma).


title:
Excess Cross-Sections at the Electroweak Scale in the Sextet Quark
  ``Standard Model''

abstract:
  If dynamical electroweak symmetry breaking is due to a flavor doublet of
color sextet quarks, enhanced electroweak scale QCD instanton interactions may
produce a large top mass, raise the $\eta_6$ axion mass, and also explain the
excesses in the DIS cross-section at HERA and jet cross-sections at the
Tevatron.


title: Some Possibilities for Charm Studies at B-factories

abstract:
  To provide focus to my review of charm theory at the B-Physics and
CP-Violation conference, I consider theoretical issues related to possible
charm studies at B-factories. A few topics of interest to the author are
stressed -- rare decays, CP-violating asymmetries and ${\bar D}^0 - D^0$
mixing.


title: On Normal ordering and Canonical transformations in Thermal Field Theory

abstract:
  We look at a real scalar field in thermal equilibrium in the context of the
new normal ordering and field split defined by Evans and Steer. We show that
the field split defines a natural canonical transformation, but that this
transformation differs from others known in thermal field theory.


title: Gauge Invariance and the Unstable Particle

abstract:
  It is shown how to construct exactly gauge-invariant S-matrix elements for
processes involving unstable gauge particles such as the $Z^0$ boson. The
results are applied to derive a physically meaningful expression for the
cross-section $\sigma(e^+e^-\to Z^0Z^0)$ and thereby provide a solution to the
long-standing problem of the unstable particle.


title: Diquark confinement in an extended NJL model

abstract:
  In a Nambu-Jona-Lasinio model supplemented with an infrared cutoff in
addition to the ultraviolet cutoff we study the issue whether diquarks are
confined when the model is extended beyond the rainbow-ladder approximation.
The gap equation, obtained in a truncation scheme motivated via a nontrivial
quark-gluon vertex function, is solved to determine the constituent quark mass
if chiral symmetry is spontaneously broken. In a second step, the
Bethe-Salpeter equations for mesons and diquarks beyond ladder approximation
are derived, taking care to preserve Goldstone's theorem in the pion channel.
While the obtained masses of pseudoscalar and vector mesons are only moderately
shifted compared to the values in ladder approximation, we observe that scalar
diquarks disappear from the physical spectrum and therefore are confined. For
axialvector diquarks we observe indications, that the same mechanism may also
work, but the NJL model allows no conclusive answer in this channel.


title: BFKL: a minireview

abstract:
  We summarize the state of the art of resummation techniques in the small-$x$
limit of perturbative QCD.


title: pi-N charge exchange and pi(+)-pi(0) scattering at low energies

abstract:
  pi-N and pi-pi interactions near threshold are uniquely sensitive to the
chiral symmetry breaking part of the strong interaction. The pi-N sigma-term
value with its implications for nucleon quark structure and the recent
controversy concerning the size of the scalar quark condensate have renewed the
experimental interest in these two fundamental systems. We report new
differential cross sections for the reaction $pi^-p \to \pi^0n$ at 27.5 MeV
pion incident kinetic energy, measured between $\theta_{CM} = 0^\circ$ and
$55^\circ$. Our results are in excellent agreement with the existing
comprehensive pi-N phase shift analysis. We also report on a Chew-Low analysis
of exclusive $\pi^+ p \to \pi^+\pi^0p$ data at 260 MeV pion incident energy.


title: Simple Gauge-mediated Models with Local Minima

abstract:
  We describe a simple class of supersymmetric gauge theories that can act as
supersymmetry-breaking sectors for gauge-mediated supersymmetry breaking. The
models have a local supersymmetry-breaking minimum along a direction in field
space where a singlet gets a large expectation value. The potential along this
direction has a runaway behavior stabilized by supersymmetry breaking in the
effective low-energy theory. The supersymmetric vacua are at infinite field
values, and cosmological bounds on false vacuum decay are easily satisfied. The
models have no dimensionful parameters, and all mass scales arise through
strong coupling dynamics. Simple variants of the model are compatible with
perturbative unification, can naturally have dynamical supersymmetry breaking
at a scale as low as 10 TeV, and can solve the R axion problem without
appealing to Planck-scale effects.


title:
Dynamical Tuning of the Initial Condition for New Inflation in
  Supergravity

abstract:
  We point out that for a class of `new inflation' models in supergravity the
required initial value of the inflaton field is dynamically set if there is
another inflation (`pre-inflation') before the `new inflation'. We study the
dynamics of both inflatons by taking a hybrid inflation model for the
`pre-inflation' as an example. We find out that our `new inflation' model
provides reheating temperatures T_R \simeq 10 MeV - 10^4 GeV low enough to
avoid the gravitino problem even in gauge-mediated supersymmetry-breaking
models. We also construct a model where the scale for the `new inflation' is
generated by nonperturbative dynamics of a supersymmetric gauge theory.


title:
Effects of the magnetic dipole moment of charged vector mesons in their
  radiative decay distribution

abstract:
  We consider the effects of anomalous magnetic dipole moments of vector mesons
in the decay distribution of photons emitted in two-pseudoscalar decays of
charged vector mesons. By choosing a kinematical configuration appropriate to
isolate these effects from model-dependent and dominant bremsstrahlung
contributions, we show that this method can provide a valid alternative for a
measurement of the unknown magnetic dipole moments of charged vector mesons.


title:
CP- and T-Violation Effects in Long Baseline Neutrino Oscillation
  Experiments

abstract:
  We examine how large CP- and T-violation effects are allowed in long baseline
neutrino experiments with three generations of neutrinos, considering both the
solar neutrino deficit and the atmospheric neutrino anomaly. We considerd two
cases: When we attribute only the atmospheric neutrino anomaly to neutrino
oscillation and assume the constant transition probability of electron neutrino
to explain the solar neutrino deficit, we may have large CP-violation effect.
When we attribute both the atmospheric neutrino anomaly and the solar neutrino
deficit to neutrino oscillation, we can see sizable T-violation effects. In
this case, however, we cannot ignore the matter effect and we will not see the
pure CP-violation effect. We also show simple methods how to separate pure CP
violating effect from the matter effect. We give compact formulae for neutrino
oscillation probabilities assuming one of the three neutrino masses (presumably
tau neutrino mass) to be much larger than the other masses and the effective
mass due to matter effect. Two methods are shown: One is to observe envelopes
of the curves of oscillation probabilities as functions of neutrino energy; a
merit of this method is that only a single detector is enough to determine the
presence of CP violation. The other is to compare experiments with at least two
different baseline lengths; this has a merit that it needs only narrow energy
range of oscillation data.


title:
Erratum for "Fractionally Charged Particles and Supersymmetry Breaking
  in 4D Strings."

abstract:
  The original paper (hep-th/9209020) contains an early example of gauge
mediated supersymmetry breaking motivated by string model building. In this
erratum we point out an important misprint in the abstract of the published
version (Phys. Lett. B295 (1992) 219) which may confuse the reader. We also
correct the computation of scalar masses and the numerical examples.
Qualitative results remain the same.


title:
Dynamical Determination of the Top Quark and Higgs Masses and Fermion
  Masses in the Anti-Grand Unification Model

abstract:
  The multiple point criticality principle is applied to the pure Standard
Model (SM), with a desert up to the Planck scale. We are thereby led to impose
the constraint that the effective Higgs potential should have two degenerate
minima, one of which should have a vacuum expectation value of order unity in
Planck units. In this way we predict a top quark mass of $173 \pm 5$ GeV and a
Higgs particle mass of $135 \pm 9$ GeV. The quark and lepton mass matrices are
considered in the anti-grand unified extension of the SM based on the gauge
group $SMG^3 \otimes U(1)_f$; this group contains three copies of the SM gauge
group SMG, one for each generation, and an abelian flavour group $U(1)_f$. The
9 quark and lepton masses and 3 mixing angles are fitted using 3 free
parameters, with the overall mass scale set by the electroweak interaction. It
is pointed out that the same results can be obtained in an anomaly free $SMG
\otimes U(1)^3$ model.


title:
Spectral Density Functions and Their Sum Rules in an Effective Chiral
  Field Theory

abstract:
  The validity of Weinberg's two sum rules for massless QCD, as well as the six
additional sum rules introduced into chiral perturbation theory by Gasser and
Leutwyler, are investigated for the extended Nambu-Jona-Lasinio chiral model
that includes vector and axial vector degrees of freedom. A detailed analysis
of the vector, axial vector and coupled pion plus longitudinal axial vector
modes is given. We show that, under Pauli-Villars regularization of the meson
polarization amplitudes that determine the spectral density functions, all of
the sum rules involving inverse moments higher than zero are automatically
obeyed by the model spectral densities. By contrast, the zero moment sum rules
acquire a non-vanishing right hand side that is proportional to the quark
condensate density of the non-perturbative groundstate. We use selected sum
rules in conjunction with other calculations to obtain explicit expressions for
the scale-independent coupling constants $\bar l_i$ of chiral perturbation
theory in the combination $\bar l_i+\ln(m^2_\pi/\mu^2)$, to evaluate the
Das-Guralnik-Mathur-Low-Young current algebra expression for the
electromagnetic mass difference of the pion, and to compute the pion electrical
polarizability $\alpha_E$. The sum rule calculations %of $\alpha_E$ set an
upper limit of $\alpha_E\leq \alpha/(8\pi^2m_\pi f^2_\pi) \approx
6\times10^{-4}$fm$^3$ on this quantity, that is independent of the quark mass
up to ${\cal O}(m^2_\pi/m^2)$, and only depends on the fundamental constants:
pion mass $m_\pi$ and pion decay constant $f_\pi$, in addition to fine
structure constant $\alpha\approx 1/137$.


title:
R-parity Conserving Supersymmetry, Neutrino Mass and Neutrinoless Double
  Beta Decay

abstract:
  We consider contributions of R-parity conserving softly broken supersymmetry
(SUSY) to neutrinoless double beta ($\znbb$) decay via the (B-L)-violating
sneutrino mass term. The latter is a generic ingredient of any weak-scale SUSY
model with a Majorana neutrino mass. The new R-parity conserving SUSY
contributions to $\znbb$ are realized at the level of box diagrams. We derive
the effective Lagrangian describing the SUSY-box mechanism of $\znbb$-decay and
the corresponding nuclear matrix elements. The 1-loop sneutrino contribution to
the Majorana neutrino mass is also derived.
  Given the data on the $\znbb$-decay half-life of $^{76}$Ge and the neutrino
mass we obtain constraints on the (B-L)-violating sneutrino mass. These
constraints leave room for accelerator searches for certain manifestations of
the 2nd and 3rd generation (B-L)-violating sneutrino mass term, but are most
probably too tight for first generation (B-L)-violating sneutrino masses to be
searched for directly.


title:
Next-to-leading order Q^2-evolution of the transversity distribution
  h_1(x, Q^2)

abstract:
  We present a calculation of the two-loop anomalous dimension for the
transversity distribution h_1(x,Q^2), $\gamma^{h(1)}_n$, in the MS scheme of
the dimensional regularization. Due to the chiral-odd nature, h_1 does not mix
with the gluon distributions, and thus our result is the same for the
flavor-singlet and nonsinglet distributions. At small n (moment of h_1),
$\gamma^{h(1)}_n$ is significantly larger than $\gamma^{f(1)}_n$ (the anomalous
dimension for the nonsinglet f_1), but approaches $\gamma^{f(1)}_n$ very
quickly at large n, keeping the relation $\gamma^{h(1)}_n > \gamma^{f(1)}_n$.
This feature is in parallel to the relation between the one-loop anomalous
dimension for f_1 and h_1.


title:
Soft supersymmetry-breaking terms from supergravity and superstring
  models

abstract:
  We review the origin of soft supersymmetry-breaking terms in N=1 supergravity
models of particle physics. We first consider general formulae for those terms
in general models with a hidden sector breaking supersymmetry at an
intermediate energy scale. The results for some simple models are given. We
then consider the results obtained in some simple superstring models in which
particular assumptions about the origin of supersymmetry breaking are made.
These are models in which the seed of supersymmetry breaking is assumed to be
originated in the dilaton/moduli sector of the theory.


title: A Dynamical Eta'-Mass from an Infrared Enhanced Gluon Exchange

abstract:
  The pseudo-scalar flavor-singlet meson mixes with two gluons. A dimensional
argument by Kogut and Susskind shows that this can screen the Goldstone pole of
the chiral limit in this channel, if the gluon correlations are infrared
enhanced. Using a gluon propagator as singular as sigma/k^4 for k^2 -> 0 we
relate the screening mass to the string tension sigma. In the Witten-Veneziano
action to describe the eta-eta' mixing this relation yields masses of about
810MeV for the eta', 430MeV for the eta and a mixing angle of about -30deg from
the phenomenological value for sigma of approx. 0.18GeV^2. The very weak
temperature dependence of the string tension should make this mechanism
experimentally distinguishable from exponentially temperature dependent
instanton model predictions.


title: General Tests for t ---> W+ b couplings at Hadron Colliders

abstract:
  The modularity property of the helicity formalism is used to provide
amplitude expressions and stage-two spin-correlation functions which can easily
be used in direct experimental searches for electro-weak symmetries and
dynamics in the decay processes $t \to W^+ b$, $\bar t \to W^- \bar b$. The
formalism is used to describe the decay sequences $t\to W^{+}b\to (l^{+}\nu)b$,
and $t\to W^{+}b\to (j_{\bar d}j_u)b$. Helicity amplitudes for $t \to W^+ b $
are obtained for the most general $J_{\bar b t}$ current. Thereby, the most
general Lorentz-invariant decay-density-matrix for $t\to W^{+}b\to
(l^{+}\nu)b$, or for $t\to W^{+}b\to (j_{\bar d}j_u)b$, is expressed in terms
of eight helicity parameters and, equivalently, in terms of the structures of
the $J_{\bar b t}$ current. The parameters are physically defined in terms of
partial-width-intensities for polarized-final-states in \newline $t\to W^{+}b$
decay. The full angular distribution for the reactions $q \bar q$ and $g g \to
t \bar t \to (W^+ b) (W^- \bar b) \to ...$ can be used to measure these
parameters. Since this adds on spin-correlation information from the next stage
of decays in the decay sequence, such an energy-angular distribution is called
a stage-two spin-correlation (S2SC) function.


title: $K_L \to \pi^o \nu \bar{\nu}$ in the Aspon Model

abstract:
  An attractive alternative to the standard model of CP violation is the aspon
model. In this model, CP is spontaneously broken, automatically solving the
strong CP problem. Recently, it has been shown that CP violation in the B
system is much smaller in the aspon model than in the standard model. Here we
provide a complementary study by considering $K_L\to \pi^o\nu\bar{\nu}$, which
is almost entirely CP violating and free of hadronic uncertainties, and show
that the rate in the aspon model is many orders of magnitude below the standard
model rate. Observation of $K_L\to \pi^o\nu\bar{\nu}$ would rule out the aspon
model.


title: Higgs Boson Masses and Couplings in the Minimal Supersymmetric Model

abstract:
  The Higgs sector of the Minimal Supersymmetric Model (MSSM) is a
CP-conserving two-Higgs doublet model that depends, at tree-level, on two Higgs
sector parameters. In order to accurately determine the phenomenological
implications of this model, one must include the effects of radiative
corrections. The leading contributions to the one-loop radiative corrections
are exhibited; large logarithms are resummed by the renormalization group
method. Implications for Higgs phenomenology are briefly discussed.


title: S, T, and Leptoquarks at HERA

abstract:
  If the recently discovered anomalous events at HERA are due to a scalar
leptoquark, then it is very likely to have weak isospin $I = 1/2$. In that
case, present precision measurements of the oblique radiative parameters $S$
and $T$ provide strong constraints on the mass of the other component of this
doublet. If the standard model is extended to include such a doublet, a
slightly better fit may in fact be obtained. However, in specific proposed
models where this doublet comes from a larger symmetry, there are often
additional large and positive contributions to $S$ from exotic heavy fermions
which far exceed the present experimental limit. A way to improve the Tevatron
exploration of leptoquarks is proposed.


title: Flavor Symmetries and the Description of Flavor Mixing

abstract:
  It is shown that the hierarchical structure of the quark mass terms in the
standard model suggests a new description of the flavor mixing. The latter is
primarily a heavy quark mixing involving the t and b quarks, followed by a
mixing exclusively in the u-channel or the d-channel. The complex phase
describing CP violation arises only in the light quark sector. The Cabibbo
angle is not a basic parameter, but results as a superposition of both the
u-channel and d-channel mixing terms. The new description has a number of
significant advantages in comparison with all descriptions previously used. It
is suggested that the new description be used in all future discussions of
flavor physics and CP violation.


title:
Surface Induced Phase Transition in Quark-Gluon Plasma Produced in
  Laboratory

abstract:
  We discuss an outside-inside scenario for a first order quark-hadron
transition in the Quark-Gluon Plasma (QGP) expected to be produced in heavy ion
collisions, wherein the entire QGP region itself becomes like a subcritical
bubble, and starts shrinking. We argue that this shrinking QGP bubble will lead
to concentration of baryon number in a narrow beam like region in center, which
can be detected by HBT analysis, or as a raised plateau in the rapidity plot of
baryon number.


title: Theory of Beauty Lifetimes

abstract:
  A critical review of the theoretical understanding of the lifetimes of beauty
hadrons is given. A model-independent analysis using the heavy-quark expansion
allows for a description of the lifetime ratios tau(B-)/tau(B0) and
tau(Lambda_b)/tau(B0) in a small region of parameter space. It is demonstrated
that the lifetime ratio tau(B-)/tau(B0) cannot be used to extract the decay
constant of the B meson. Implications for the semileptonic branching ratio and
charm yield in B decays are pointed out.


title: How quark hadron duality in QCD may work

abstract:
  We pursue the issue of the local quark-hadron duality at high energies in
two- and four-dimensional QCD. A mechanism of the dynamical realization of the
quark-hadron duality in two-dimensional QCD in the limit of large number of
colors, $N_c \to \infty$, (the ' t Hooft model) is investigated. We argue that
a similar mechanism of dynamical smearing may be relevant in four-dimensional
QCD. Although particular details of our results are model-dependent (especially
in the latter case), the general features of the duality implementation
conjectured previously get further support.


title: Elastic nucleon scattering at small angles at LHC energies

abstract:
  Predictions of the elastic proton-proton cross sections at energies of LHC
are calculate on the base of the high energy dynamical model. The growth of
$ds/dt$ at fixed transfer momenta are shown. The form of eikonal of elastic
hadron scattering at super high energies is discussed.


title:
Numerical solution of Q^2 evolution equations for polarized structure
  functions

abstract:
  We investigate numerical solution of
Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) Q^2 evolution equations for
longitudinally polarized structure functions. Flavor nonsinglet and singlet
equations with next-to-leading-order $\alpha_s$ corrections are studied. A
brute-force method is employed. Dividing the variables x and Q^2 into small
steps, we simply solve the integrodifferential equations. Numerical results
indicate that accuracy is better than 1% in the region 10^{-5}<x<0.8 if more
than two-hundred Q^2 steps and more than one-thousand x steps are taken. Our
evolution results are compared with polarized experimental data of the spin
asymmetry A_1 by the SLAC-E130, SLAC-E143, EMC, and SMC collaborations. The
comparison indicates that we cannot assume A_1 is independent of Q^2. We
provide a FORTRAN program for the Q^2 evolution and devolution of polarized
nonsinglet-quark, singlet-quark, Delta q_i+ Delta q-bar_i, and gluon
distributions (and corresponding structure functions).


title:
Simulation of Vortex-Antivortex Pair Production in a Phase Transition
  with Explicit Symettry Breaking

abstract:
  We carry out numerical simulation of the formation of U(1) global vortices in
a first order phase transition in 2+1 dimensions in the presence of small
explicit symmetry breaking. Bubbles of broken symmetry phase are randomly
nucleated, which grow and coalesce. Vortices form at junctions of bubbles via
standard Kibble mechanism as well as due to a new mechanism, recently proposed
by us, where defect-antidefect pairs are produced due to field oscillations. In
a simulation involving nucleation of 63 bubbles, with bias in phase
distribution inside bubbles arising from explicit symmetry breaking, we find
that not a single vortex/antivortex is produced via the Kibble mechanism, while
the new mechanism leads to production of 104 vortices and antivortices. Even
without biasing the phase distribution inside bubbles, the vortex production is
completely dominated by this new mechanism, which accounts for the production
of about 80% of the vortices and antivortices, remaining 20% being produced via
the Kibble mechanism. We study the dependence of the effectiveness of the new
mechanism on the magnitude of explicit symmetry breaking, as well as on the
nucleation rate of bubbles. We also study the effect of damping on this
mechanism and show that damping suppresses this mode of vortex production.


title: Determination of the CKM unitarity triangle by B -> X_d l^+ l^- decay

abstract:
  I examine a possibility to extract the angle $\gamma$ of the
Cabibbo-Kobayashi-Maskawa unitarity triangle by the inclusive $B \to X_d \l^+
\l^- $ decay. An independent information for the angle is expected from the
non-trivial contribution induced in $u \bar{u}$ and $c \bar{c}$ loops. The
contributions induce CP asymmetry which has high sensitivity to the angle
$\gamma$ in the whole dilepton invariant mass region. Particularly, in the low
dilepton invariant mass region, the sensitivity is also recognized in the
branching-ratio with any dilepton final states and the lepton polarization
asymmetry with dimuon final state. In the high dilepton invariant mass region,
the sensitivity is tiny in all measurements with the exception of the CP
asymmetry, that make them to be good probes to confirm the measurement of
${V_{td}}^\ast V_{tb}$ in addition to the present data from $B_d^0-\bar{B}_d^0$
mixing. The decay rate and asymmetries are examined in the Standard Model with
taking into account the long-distance contributions due to vector-mesons as
well as its momentum dependences that would reduce the long-distance
backgrounds in the channel.


title: NLO Production and Decay of Quarkonium

abstract:
  We present a calculation of next-to-leading-order (NLO) QCD corrections to
total hadronic production cross sections and to light-hadron-decay rates of
heavy quarkonium states. Both colour-singlet and colour-octet contributions are
included. We discuss in detail the use of covariant projectors in dimensional
regularization, the structure of soft-gluon emission and the overall finiteness
of radiative corrections. We compare our approach with the
  NLO version of the threshold-expansion technique recently introduced by
  Braaten and Chen. Most of the results presented here are new. Others
represent the first independent reevaluation of calculations already known in
the literature. In this case a comparison with previous findings is reported.


title:
A complete ${\cal O}(\alpha \alpha_s)$ calculation of the Photon + 1 Jet
  rate in $e^+e^-$ annihilation

abstract:
  We present a complete calculation of the photon +~1 jet rate in $e^+e^-$
annihilation up to ${\cal O}(\alpha \alpha_{s})$. Although formally of
next-to-leading order in perturbation theory, this calculation contains several
ingredients appropriate to a next-to-next-to-leading order calculation of jet
observables. In particular, we describe a generalization of the commonly used
phase space slicing method to isolate the singularities present when more than
one particle is unresolved. Within this approach, we analytically evaluate the
singularities associated with the following double unresolved regions; triple
collinear, soft/collinear and double single collinear configurations as well as
those from the collinear limit of virtual graphs. By comparing the results of
our calculation with the existing data on the photon +~1 jet rate from the
ALEPH Collaboration at CERN, we make a next-to-leading order determination of
the process-independent non-perturbative quark-to-photon fragmentation function
$D_{q \to \gamma}(z,\mu_{F})$ at ${\cal O}(\alpha \alpha_{s})$. As a first
application of this measurement allied with our improved perturbative
calculation, we determine the dependence of the isolated photon +~1 jet cross
section in a democratic clustering approach on the jet resolution parameter
$\ycut$ at next-to-leading order. The next-to-leading order corrections to this
observable are moderate but improve the agreement between theoretical
prediction and experimental data.


title:
QCD Corrections to Flavor-Changing Neutral Currents in the
  Supersymmetric Standard Model

abstract:
  We compute the leading QCD corrections to K-Kbar mixing in the supersymmetric
standard model with general soft supersymmetry-breaking parameters. We
construct the \Delta S=2 effective Lagrangian for three hierarchies of
supersymmetric particle masses, namely, when the gluino mass is comparable to,
much greater than, or much less than the masses of the first two generation
squarks. We find that the QCD corrections tighten the limits on squark mass
splittings by more than a factor of two.


title: Strange Magnetic Moment and Isospin Symmetry Breaking

abstract:
  The small mass difference $m_n-m_p=1.3 MeV$ between the proton and neutron
leads to an excess of $n=\pi^- p$ over $p=\pi^+ n$ fluctuations which can be
calculated by using a light-cone meson-baryon fluctuation model of intrinsic
quark-antiquark pairs of the nucleon sea. The Gottfried sum rule violation may
partially be explained by isospin symmetry breaking between the proton and
neutron and the same effect introduces correction terms to the anomalous
magnetic moments and the anomalous weak magnetic moments of the proton and
neutron. We also evaluated the strange magnetic moment of the nucleon from the
lowest strangeness $K \Lambda$ fluctuation and found a non-trivial influence
due to isospin symmetry breaking in the experimental measurements of the
strange magnetic moment of the nucleon.


title: A New Method Of Distinguishing Models For The High-$Q^2$ Events At HERA

abstract:
  Many explanations for the excess high-Q^2 $e^+p \to e^+X$ events from H1 and
ZEUS at HERA have been proposed each with criticisms. We propose a new method
to distinguish different models by looking at a new distribution which is
insensitive to parton distribution function but sensitive to new physics.


title: Chiral Perturbation Theory in Few-Nucleon Systems

abstract:
  The low-energy effective theory of nuclear physics based on chiral symmetry
is reviewed. Topics discussed include the nucleon-nucleon force, few-body
potentials, isospin violation, pion-deuteron scattering, proton-neutron
radiative capture, pion photoproduction on the deuteron, and pion production in
proton-proton collisions.


title: $t \to cWW$ and $WW \to \bar{t}c + t\bar{c}$ in Extended Models

abstract:
  Jenkins has pointed out that the process $t\to cW^+W^-$ is GIM suppressed in
the standard model. In this note, we calculate the branching ratio for a wide
range of models, in which the decay occurs at tree level through exchange of a
scalar, fermion or vector. In the case of scalar exchange, a scalar mass
between $2m_W$ and 200 GeV leads to a resonant enhancement, giving a branching
ratio as high as a few tenths of a percent. We then note that all of these
models will also allow $W^+W^-\to \bar{t}c+t\bar{c}$, and we calculate the
single-top/single-charm production rate at the LHC. The rates aren't negligibly
small, but the background from single-top/single-bottom production will
probably swamp the signal.


title:
Isospin-Breaking Vacuum-to-Pi^0,Eta Pseudoscalar Matrix Elements at
  Next-to-Leading Order in the Chiral Expansion

abstract:
  We employ Chiral Perturbation Theory (ChPT) to evaluate the complete set of
pseudoscalar matrix elements, <0|P_f|pi^0,eta>, with P_f any of the
flavor-diagonal pseudoscalar currents (f=u,d,s), to order (m_d-m_u), and to
next-to-leading order in the chiral expansion. These matrix elements represent
the basic input to a QCD sum rule analysis of isospin breaking in the pi NN
couplings using the three-point-function method. We discuss also how one could
use the results to construct a one parameter family of interpolating fields for
the $\pi^0$, all of whose members have zero vacuum-to-$\eta$ matrix element,
and explain how this could in principle be used to provide non-trivial tests of
the reliability of the assumptions underlying the use of the
three-point-function method. It is shown that the isospin-breaking mixing
parameters required for this construction receive significant corrections
beyond leading order in the chiral expansion.


title:
Higher Resonance Contamination of pi NN Couplings Obtained Via the
  Three-Point Function Method in QCD Sum Rules

abstract:
  We investigate the size of potential higher pseudoscalar resonance
contaminations of the estimates of isospin-conserving and isospin-violating
$\pi NN$ couplings obtained using the 3-point function method in QCD sum rules.
For the isospin-conserving case it is shown that conventional models of the
isovector pseudoscalar spectral function imply resonance decay constants large
enough to create significant contaminations, and that assuming these models are
incorrect, and that the decay constants are actually much smaller, implies
physically implausible values for the flavor-breaking quark condensate ratios.
For the isospin-violating case it is shown explicitly that such resonance
contamination is unavoidably present and precludes using the 3-point function
method as a means of estimating the at present unmeasured isospin-violating
$\pi NN$ couplings.


title:
Electromagnetic masses of the mesons and the generalization of Dashen's
  theorem

abstract:
  In the framework of $U(3)_L\times U(3)_R$ chiral field theory, Dashen's
theorem is reexamined, and the well-known result of $m_{\pi^\pm}^2-m_{\pi^0}^2$
obtained by Das, Guralnik, Mathur, Low, and Young is reproduced. We find that
Dashen's theorem, which automatically holds for pseudoscalar mesons in this
theory, can be generalized to the sector of axial-vector mesons, however, fails
for the sector of vector mesons.


title: A Colored Particle Acceleration by Fluctuations in QGP

abstract:
  We discuss the energy variation of a parton passing through a quark-gluon
plasma(QGP) taking into account nonlinear polarization effect. We find the
parton can be accelerated by fluctuations in QGP, which gives us a new physical
insight about the response of QGP to such external the current.


title:
Standard Model Couplings with $\alpha^{-1}=137 \pm 9$ from Multiple
  Point Criticality and 3 Generations of Gauge Bosons: No GUT, No SUSY

abstract:
  We consider the application of the Multiple Point Criticality Principle to
the Standard Model and its extension to the anti-grand gauge group $SMG^3
\otimes U(1)_f$ at the Planck scale. In particular we discuss the predictions
for the fine structure constants: $\alpha^{-1}(0) = 137 \pm 9$,
$\alpha^{-1}_{1}(M_Z) =99 \pm 5$, $\alpha^{-1}_{2}(M_Z) =29 \pm 6$,
$\alpha^{-1}_{3}(M_Z) =12 \pm 6$. We also present our Standard Model
predictions for the top quark and Higgs masses and a $SMG^3 \otimes U(1)_f$ fit
of the quark-lepton masses and mixing angles. We characterise $SMG^3 \otimes
U(1)_f$ as the largest possible extension of the Standard Model gauge group
satisfying some relatively simple assumptions. The resolution of some other
fine-tuning problems ($\Lambda_{cosmological}$, $\Theta_{QCD}$, $M_{Higgs}$) by
the multiple point requirement of degenerate vacua is briefly discussed.


title: CP Violation and Baryogenesis due to Heavy Majorana Neutrinos

abstract:
  We analyze the scenario of baryogenesis through leptogenesis induced by the
out-of-equilibrium decays of heavy Majorana neutrinos and pay special attention
to CP violation. Extending a recently proposed resummation formalism for
two-fermion mixing to decay amplitudes, we calculate the resonant phenomenon of
CP violation due to the mixing of two nearly degenerate heavy Majorana
neutrinos. Solving numerically the relevant Boltzmann equations, we find that
the isosinglet Majorana mass may range from 1 TeV up to the grand unification
scale, depending on the mechanism of CP violation and/or the flavour structure
of the neutrino mass matrix assumed. Finite temperature effects and possible
constraints from the electric dipole moment of electron and other low-energy
experiments are briefly discussed.


title: Metastable Defects in the Generic 2HSM

abstract:
  A new kind of classically stable static solitons called metastable
quasi-topological defects (MQTD) and a systematic method to search for them is
presented, with examples from realistic particle physics models. They are
characterized by a topological winding number, which is not absolutely
conserved so that the MQTD may be converted to radiation by quantum mecanical
tunneling. The two-Higgs standard model (2HSM) supports the existence of
classically stable membranes for Higgs masses consistent with present day
phenomenology and with perturbative unitarity, as well as with loop corrected
MSSM. We also comment upon the possibility of metastable strings in the generic
2HSM.


title: Evolution equations and angular ordering at small x

abstract:
  This talks examines the effect of angular ordering on the small-x evolution
of the unintegrated gluon distribution, and discusses the characteristic
function for the CCFM equation.


title: Photon '97: Theory Summary

abstract:
  Some recent developments in the physics of photon induced reactions are
discussed. My presentation is biased towards HERA physics with the other
summary talk (of David Miller) being biased towards the gamma-gamma topics.
Within the context of the data which were presented, I concentrate upon the the
following topics: diffraction; jets; prompt photons; open charm and charmonium.


title:
Testing Gauge-Gravitino Coupling in Gauge-Mediated Supersymmetry
  Breaking Through Single Photon Events

abstract:
  We show that the process $e^+e^- \to \gamma+$ missing energy, arising from
the pair production of neutralinos, can probe the $\gamma-\tilde\gamma-
\gravitino$ as well as the $Z-\tilde Z-\gravitino$ couplings in Gauge Mediated
Supersymmetry Breaking models. This enables one to study the mutual
relationship of the Goldstino couplings of the different gauginos, a feature
whose testability has not been emphasized so far. The Standard Model
backgrounds get suppresed with the use of a right polarized electron beam. The
energy and angular distribution of the emitted photon can distinguish such
models from the minimal supersymmetric theory and its variants.


title:
Single particle spectra in deep inelastic scattering as a probe of small
  $x$ dynamics

abstract:
  We study the transverse momentum ($p_T$) spectrum of charged particles
produced in deep inelastic scattering (DIS) at small Bjorken $x$ in the central
region between the current jet and the proton remnants. We calculate the
spectrum at large $p_T$ with the BFKL $\ln (1/x)$ resummation included and then
repeat the calculation with it omitted. We find that data favour the former. We
normalize our BFKL predictions by comparing with HERA data for DIS containing a
forward jet. The shape of the $x$ distribution of DIS + jet data are also well
described by BFKL dynamics.


title:
New Methods for Extracting the CKM Angle $\gamma$ using $B^\pm\to D^0
  K^-$; $\bar D^0 K^-$

abstract:
  In this talk I will discuss the extraction of the CKM angle $\gamma$ at
B-factories through the interference of the subprocesses $B^-\to K^- D^0$ and
$B^- \to K^-\bar D^0$. This seemingly impossible interference may be
accomplished by allowing both $D^0$ and $\bar D^0$ to decay to a common final
state. If only CP eigenstate decay modes of the $D$ are considered, the
branching ratio for $B^- \to \bar D^0 K^-$ must be experimentally I describe
why this determination is likely to be experimentally impossible. On the other
hand, if more general $D$ decays are considered, the angle $\gamma$ may then be
determined. In fact, it is possible that a reasonable determination of $\gamma$
may be made with O(10^8) B's.


title:
New Multi-Scale Supersymmetric Models with Flavor Changing Neutral
  Current Suppression

abstract:
  We discuss the phenomenology of a class of supersymmetric models in which
some of the quark and lepton superfields are an integral part of a dynamical
supersymmetry breaking sector. The corresponding squarks and sleptons are much
heavier than any other superpartners, and could naturally have masses as high
as ~ 40 TeV. We discuss a general set of conditions for acceptable
flavor-changing neutral currents and natural electroweak symmetry breaking, and
identify two particularly interesting new classes of theories. We discuss how
phenomenological signatures of such multi-scale models at the CERN LEP II and
Fermilab Tevatron colliders could significantly differ from previously
considered scenarios. In particular, we give experimental signals which could
be present if the left-handed selectron is much lighter than the right-handed
one.


title:
Two-Loop Large-$m_t$ Electroweak Corrections to $K\to\pi\nu\bar\nu$ for
  Arbitrary Higgs Boson Mass

abstract:
  We consider for the first time the leading large top mass corrections,
arising at higher order in electroweak interactions, to the rare decays
$K\to\pi\nu\bar\nu$ and the related modes $B\to X_s\nu\bar\nu$ and $B\to
l^+l^-$. Higher order effects of similar type have previously been calculated
in the large-$m_t$ limit for key observables of precision electroweak physics
at Z-factories. Here we obtain the corresponding corrections of order ${\cal
O}(G^2_F m^4_t)$ at the amplitude level for short-distance dominated rare meson
decays. This allows us to quantify the importance of higher order electroweak
effects for these processes, which can be reliably computed and have very small
uncertainties from strong interactions. Simultaneously it becomes possible to
remove, to some extent, ambiguities in the definition of electroweak parameters
describing the strength of FCNC interactions. The corrections we discuss are at
the level of a few percent.


title: Slepton Production as a Probe of the Squark Mass Scale

abstract:
  We investigate an important radiative correction to the slepton and chargino
production processes. We consider a supersymmetric spectrum with a large
splitting between the squark and slepton masses. In this case, in the effective
theory below the squark mass threshold, the supersymmetric Slavnov-Taylor
identities which enforce the equality of the gauge and gaugino couplings are
violated. The gaugino propagators receive potentially large corrections due to
virtual quark/squark loop effects. We compute the full one-loop (s)quark
corrected slepton production cross-sections. The t-channel one-loop scattering
amplitudes are factorized into an effective chargino/neutralino mass matrix and
an effective fermion-sfermion-gaugino coupling. The difference between the
effective gaugino coupling and the gauge coupling is proportional to
log(Msq/msl) in the large squark mass limit. We find that the one-loop
corrected slepton production cross-sections can depend on the squark mass
strongly, up to 9% times log(Msq/msl). We investigate the squark mass
sensitivity of the slepton cross-section measurements at a future linear
collider. For sneutrino production accessible at sqrt{s}= 500 GeV there can be
sensitivity to squark masses at or larger than 1 TeV.


title: Disoriented chiral condensate formation from tubes of hot quark plasma

abstract:
  We investigate the time evolution of a system of quarks interacting with
sigma and pion fields starting from an initial configuration consisting of a
tube of hot quark plasma undergoing a boost-invariant longitudinal expansion.
We work within the framework of the linear sigma model using classical
transport equations for the quarks coupled to the mean-field equations for the
meson fields. In certain cases we find strong amplifications of any initial
pion fields. For large-radius tubes, starting from quark densities that are
very close to critical, we find that a disoriented chiral condensate can form
in the centre of the tube. Eventually the collapse of the tube drives this
state back to the true vacuum. This process converts the disoriented
condensate, dominated by long-wavelength pion modes, into a coherent excitation
of the pion field that includes significant components with transverse momenta
of around 400 MeV. In contrast, for narrow tubes or larger initial
temperatures, amplification occurs only via the pion-laser-like mechanism found
previously for spherical systems. In addition, we find that explicit chiral
symmetry breaking significantly suppresses the formation of disoriented
condensates.


title:
Resonant and non-resonant amplification of massless gauge fields during
  an oscillating dilaton phase

abstract:
  The resonant and non-resonant amplification of electromagnetic
inhomogeneities is investigated within a phase of coherent dilaton
oscillations. We show, in some explicit toy model, how the critical energy
density bound applied to the amplified fluctuations of the massless gauge
fields can constrain the dilaton mass.


title: Gluon evolution at low $x$ and the longitudinal structure function

abstract:
  We obtain an approximate analytical form of the gluon distribution using the
GLAP equation with a factorization ansatz,and test its validity by comparing it
with that of Gluck,Reya and Vogt at low $x$ regime. We also present
calculations of the longitudinal structure functions.


title: The Contribution of Bc Mesons to the Search for B->tau nu Decays at LEP

abstract:
  We study the contribution of B_c mesons to the search for B->tau nu decays.
We find that at LEP the contributions from B_u and B_c mesons can be
comparable. This observation can have a relevant impact on the extraction of
constraints on new physics (such as charged-Higgs contributions) from current
LEP limits on B->tau nu final states. Inclusion of the B_c contribution can
reduce the current L3 limit on Tan(beta)/M_H from 0.38/GeV (90%CL) down to
0.27/GeV (90%CL).


title: Gravitational divergences as a mediator of supersymmetry breaking

abstract:
  Gravitational divergences associated with singlet fields in supersymmetric
theories are reexamined, and their possible contributions to the low-energy
effective theory are pointed out. We demonstrate that such divergences are not
necessarily harmful and that Planck-scale physics could play an important role
in models of low-energy supersymmetry breaking via a radiatively induced
tadpole term in the scalar potential. In this case, gravitational divergences
play the role of the supersymmetry breaking mediator, leading to a simple
realization of the so-called messenger model. We also point out a new mechanism
for the generation of mass terms for the Higgs fields in models of low-energy
supersymmetry breaking, as well as a horizontal messenger mechanism in which
the horizontally charged scalars are rendered heavy. Implications to the flavor
problem in supersymmetric models are also discussed.


title:
A quark model analysis of the transversity distribution: Next to leading
  order evolution

abstract:
  The feasibility of measuring chiral-odd parton distribution functions in
polarized Drell-Yan and semi-inclusive experiments has renewed theoretical
interest in their study. Not long ago we presented an analysis of the
transversity distribution functions using models of hadron structure and
Leading Order evolution. In the meantime Next to Leading Order evolution
equations for $h_1$ are also available. We here present a comparison between
the LO and the NLO results which confirms our previous conclusions.


title:
An analysis of two-body non-leptonic B decays involving light mesons in
  the standard model

abstract:
  We report a theoretical analysis of the exclusive non-leptonic decays of B
mesons into two light mesons,some of which have been measured recently by the
CLEO collaboration. Our analysis is carried out in the context of an effective
Hamiltonian based on the Standard Model using next-to-leading order
perturbative QCD calculations. Using a factorization ansatz for the hadronic
matrix elements, we show that existing data are accounted for in this approach.
Thus, theoretical scenarios with a substantially enhanced Wilson coefficient of
the chromomagnetic dipole operator (as compared to the SM) and/or those with a
substantial color-singlet $c\bar{c}$ component in the wave function of
$\eta^\prime$ are not required by these data. Implications of some of these
measurements for the parameters of the CKM matrix are presented.


title:
Q**2-dependence of semi-inclusive electron-nucleus scattering and
  nucleon-nucleon correlations

abstract:
  We analize semi-inclusive electron-nucleus processes e+A->e'+h+X at moderate
Q**2 and energy transfer nu. Our results show that nucleons bound in the
nuclear medium are distributed according to a function f_A that reduces to the
standard light-cone distribution in the Bjorken limit and exhibits a sizeable
Q**2-dependence at lower Q**2, particular Q**2 is order of nu**2.


title: On extracting the rho-omega mixing amplitude from the pion form-factor

abstract:
  In this paper we improve and extend a recent analysis which showed that the
rho-omega mixing amplitude cannot be unambiguously extracted from the pion
electromagnetic form-factor in a model independent way. In particular, we focus
on the argument that the extraction is sensitive to the presence of any
intrinsic omega_I -> pi pi coupling. Our extended analysis confirms the
original conclusion, with only minor, quantitative differences. The extracted
mixing amplitude is shown to be sensitive to both the intrinsic coupling
omega_I -> pi pi and to the value assumed for the mass of the rho^0-meson.


title:
One-Loop QCD Corrections to Deeply Virtual Compton Scattering: The
  Parton Helicity-Independent Case

abstract:
  We show that the one-loop QCD correction to deeply-virtual Compton scattering
can be factorized into the finite perturbative contributions and the
collinearly-divergent terms, which correspond to the matrix elements of the
off-forward parton distributions. As a by-product, we obtain the
next-to-leading order coefficient functions in the generalized operator product
expansion of two vector currents.


title: CP Violation in EPR-like neutrino oscillations

abstract:
  After reviewing the general framework to study EPR-like neutrino
oscillations, we derive expressions for the oscillation probabilities and a
direct measure of CP violation. We compare the possibility of studying CP
violation in this case with that of baseline accelerator experiments and
conclude that it is possible to study CP violation in experiments with length
scales comparable to that of short baseline accelerator experiments.


title: Minimal Supersymmetric Left-Right Model

abstract:
  We construct the truly minimal left-right symmetric model by utilizing only
the fields dictated by supersymmetry and automatic R-parity conservation.
Allowing for non-renormalizable operators in the superpotential, we show that
parity can be spontaneously broken while preserving electromagnetic gauge
invariance. The scale of parity breakdown is predicted in the intermediate
region: $M_R > 10^{10}- 10^{11} GeV$, and R-parity remains exact. The theory
contains a number of charged and doubly charged Higgs scalars with a low mass
of order $M_R^2/M_{Planck}$, accessible to experiment.


title: Towards an Effective Theory of Small-x QCD

abstract:
  In this talk I describe recent progress in investigating the high energy
limit of perturbative QCD. I review some of the steps that have been done in
the direction of constructing an effective field theory for this limit. I
describe some of its building blocks and explain why we expect the effective
theory to be a 2+1-dimensional conformal field theory.


title:
Local nuclear slope and curvature in high energy $pp$ and $\bar pp$
  elastic scattering

abstract:
  The local nuclear slope $B(s,t) = {d \over d t} (\ln {d\sigma_n (s,t)\over
dt})$ is reconstructed from the experimental angular distributions with a
procedure that uses overlapping $t$-bins, for an energy that ranges from the
ISR to the $S\bar ppS$ and the Tevatron. Predictions of several models of
($p,p$) and ($\bar p,p$) elastic scattering at high energy are tested in
$B(s,t)$ at small $|t|$. Only a model with two-components Pomeron and Odderon
gives a satisfactory agreement with the (non fitted) slope data, in particular
for the evolution of $B(s,t)$ with $s$ as a function of $t$ in $\bar pp$
scattering. This model predicts a similar behavior for $pp$ and $\bar pp$
scattering at small $|t|$. A detailed confirmation for $pp$ collisions would be
expected from RHIC.


title: Quasi-Inclusive and Exclusive decays of $B $ to $\eta'$

abstract:
  We consider the effective Hamiltonian of four quark operators in the Standard
Model in the exclusive and quasi-inclusive decays of the type $B\to K^{(*)}
\eta^{\prime}$, $B\to \eta' X_s$, where $X_s$ contains a single Kaon. Working
in the factorization assumption we find that the four quark operators can
account for the recently measured exclusive decays $B\to \eta^{\prime}(\eta) K$
and $B\to K \pi$ for appropriate choice of form factors but cannot explain the
large quasi-inclusive rate.


title:
Automatic Calculation of Complete $O(\alpha)$ Corrections to $e^+e^- \to
  W^+\mu \bar{\nu}_{\mu}$

abstract:
  Using the automatic system GRACE-LOOP, the full $O(\alpha)$ electroweak
corrections has been calculated for the process $e^+e^- \to W^+\mu
\bar{\nu}_{\mu}$. The total correction to the cross section is found to be
typically -6.4% at $\sqrt{s}=190$ GeV with $10^\circ$ cut on the muon angle
from the beam, including the correction from the hard photon emission. It is
observed that the correction is rather sensitive to the physical parameters.
With the same conditions the correction corresponding to the real W-boson pair
is -4.1% and hence the deviation is not negligible.


title:
Residual New Physics Effects in the Heavy Quark Sector, Tests at LEP2
  and Higher Energies

abstract:
  We discuss the sensitivity of the processes $e^+e^-\to t\bar t$ and
$e^+e^-\to b\bar b$ to special sets of operators describing residual New
Physics effects. Experimental data in this sector together with those expected
in the bosonic sector should allow to constrain possible New Physics schemes
with effective scales in the 10 TeV range.


title:
The BFKL Pomeron with running coupling constant: how much of its hard
  nature survives?

abstract:
  We discuss the BFKL equation with a running gauge coupling and identify in
its solutions the contributions originating from different transverse momentum
scales. We show that for a running coupling constant the distribution of the
gluons making up the BFKL Pomeron shifts to smaller transverse momenta so that
the dominant part of Pomeron can have a nonperturbative origin. It is
demonstrated how this soft physics enters into the BFKL solution through the
boundary condition. We consider two kinematical regimes leading to different
behaviour of the rapidity and transverse momentum dependence of the gluon
distribution. In the diffusion approximation to the BFKL kernel with running
$\alpha_s$, we find a sequence of poles which replaces the cut for fixed
$\alpha_s$. The second regime corresponds to the singular part of the kernel,
which gives the dominant contribution in the limit of very large transverse
momenta. Finally, a simple more general picture is obtained for the QCD Pomeron
in hard processes: it is of soft, nonperturbative nature, but has hard ends of
DGLAP-type.


title:
Comparison between the various descriptions for charm electroproduction
  and the HERA-data

abstract:
  We examine the charm component F_{2,c}(x,Q^2,m^2) of the proton structure
function F_2(x,Q^2) in three different schemes and compare the results with the
data in the x and Q^2 region explored by the HERA experiments. Studied are (1)
the three flavour number scheme (TFNS) where the production mechanisms are
given by the photon-gluon fusion process and the higher order reactions with
three light-flavour parton densities as input (2) the four flavour number
scheme (FFNS) where F_{2,c} is expressed in four light flavour densities
including one for the charm quark and (3) a variable-flavour number scheme
(VFNS) which interpolates between the latter two. Both the VFNS and the TFNS
give good descriptions of the experimental data. However one cannot use the
FFNS for the description of the data at small Q^2.


title: Nonperturbative \gamma^* p Interaction in the Diffractive Regime

abstract:
  One of the challenging aspects of electroproduction at high-energy is the
understanding of the transition from real photons to virtual photons in the
GeV^2 region. We study inclusive electroproduction on the proton at small x_B
using a nonperturbative dipole-proton cross section calculated from the gauge
invariant gluon field correlators as input. By quark-hadron duality, we
construct a photon light cone wave function which links the ``hadronic''
behavior at small Q^2 to the ``perturbative'' behavior at large Q^2. It
contains quark masses which implement the transition from constituent quarks at
low Q^2 to current quarks at high Q^2. Our calculation gives a good description
of the structure function at fixed energy for Q^2<=10 GeV^2. Indications for a
chiral transition may already have been seen in the photon-proton cross
section.


title:
On the Nature of the Magnetic Fields Generated During the Electroweak
  Phase Transition

abstract:
  In this Letter we reanalyse the question of the origin of magnetic fields
during the electroweak phase transition. We show that their formation is
intimately connected to some semiclassical configurations of the gauge fields,
such as electroweak Z-strings and W-condensates. We describe the formation of
these semiclassical configurations during a first order phase transition and
argue that they might be generated also in the case of a second order phase
transition. We suggest that the instability of electroweak strings does not
imply the disappereance of the embedded magnetic field.


title: Diffractive Phenomena and Shadowing in Deep-Inelastic Scattering

abstract:
  Shadowing effects in deep-inelastic lepton-nucleus scattering probe the mass
spectrum of diffractive leptoproduction from individual nucleons. We explore
this relationship using current experimental information on both processes. In
recent data from the NMC and E665 collaboration, taken at small x << 0.1 and
Q^2 < 1 GeV^2, shadowing is dominated by the diffractive excitation and
coherent interaction of low mass vector mesons. If shadowing is explored at
small x << 0.1 but large Q^2 >> 1 GeV^2 as discussed at HERA, the situation is
different. Here dominant contributions come from the coherent interaction of
diffractively produced heavy mass states. Furthermore we observe that the
energy dependence of shadowing is directly related to the mass dependence of
the diffractive production cross section for free nucleon targets.


title: On Perturbative QCD at High Temperature

abstract:
  Effective field theory methods provide a convenient approach to study static
observables in field theory at finite temperature. In this talk, I will outline
the construction of the effective field theory that describes effective
observables in QCD at high temperature. An analysis of the convergence of the
perturbative series for the free energy of QCD will also be presented.


title: Of Course Muons Can Oscillate

abstract:
  Recent theoretical claims not withstanding, muons can and do oscillate. Muons
produced in association with neutrinos (if masses and mixing angles are
nonzero) exhibit a joint oscillating spatial distribution. The possible use of
muon oscillations as a probe of neutrino mass and mixing parameters is
discussed using very simple physical arguments. Space-time oscillations in the
secondary decay vertices of muons (produced by pion decay) persist after
summing over all undetected neutrinos.


title: Fragmentation Functions in Next-To-Leading Order QCD

abstract:
  We present new sets of fragmentation functions in next-to-leading order QCD
that are determined from e+e- annihilation data of inclusive particle
production. In addition to the O(alpha_s) unpolarized cross section the
longitudinal cross section is also used to extract the gluon fragmentation
function from e+e- annihilation data. As the O(alpha_s) vanishes for
longitudinal polarized photons (or Z bosons), the O(alpha_s^2) corrections are
required to reduce the scale ambiguities. Recently, P.J. Rijken and W.L. van
Neerven presented the longitudinal coefficient functions to next-to-leading
order. We confirm part of their results in this thesis and complete the
calculation by the results for the color class C_F*T_R that must be included
for a consistent comparison with LEP1 data. The complete set of coefficient
functions is then used together with novel data from ALEPH to determine the
fragmentation functions for charged hadrons. This set, and also sets for
charged pions, kaons, and D^* mesons as well as neutral kaons published
previously, can then be employed to test QCD in e+e- annihilation,
photoproduction, gamma-gamma collisions, p-p_bar scattering and DIS. Finally,
we suggest how the improved knowledge on the fragmentation in particular of the
gluon could be used to determine the gluon and charm content of the photon.


title: Baryon Spin and Magnetic Moments in Relativistic Chiral Quark Models

abstract:
  Spin-flavor fractions of quarks in the proton and several hyperons are
obtained from their lowest order chiral fluctuations involving Goldstone
bosons. SU(3) flavor breaking, relativistic effects and the axial anomaly are
included. The validity of the Karl-Sehgal formulas for magnetic moments is
studied as well.


title: Notes on $B\to K^* \gamma$

abstract:
  We analyzed two form factors $T_1(q^2)$ and $T_2(q^2)$ which enter the $B\to
K^* \ell^+ \ell^-$ decay rate and are accessible in the lattice calculations
for $B \to K^* \gamma$. The extrapolation to $q^2=0$, necessary for $B\to K^*
\gamma$ is examined. The flat behavior of $T_2(q^2)$ is shown to be disfavored.
From the double constrained unitarity bounds by the lattice result at small
recoil and the light cone sum rule one at large recoil, the pole/double pole
fit is preferred with the `pole' masses as free parameters. We also show a
consistency of two approaches in the heavy quark limit. Besides several
byproducts of this analysis, our final (conservative) result for the form
factor that determines $B\to K^* \gamma$ rate is $T(0)=0.15\pm 0.04$.


title:
Universal behavior of multiplicity differences in quark-hadron phase
  transition

abstract:
  The scaling behavior of factorial moments of the differences in
multiplicities between well separated bins in heavy-ion collisions is proposed
as a probe of quark-hadron phase transition. The method takes into account some
of the physical features of nuclear collisions that cause some difficulty in
the application of the usual method. It is shown in the Ginzburg-Landau theory
that a numerical value $\gamma$ of the scaling exponent can be determined
independent of the parameters in the problem. The universality of $\gamma$
characterizes quark-hadron phase transition, and can be tested directly by
appropriately analyzed data.


title: Comments on D-term inflation

abstract:
  An inflationary stage dominated by a D-term avoids the slow-roll problem of
inflation in supergravity and can naturally emerge in theories with a
non-anomalous or anomalous U(1) gauge symmetry. In the latter case, however,
the scale of inflation as imposed by the COBE normalization is in contrast with
the value fixed by the Green-Schwarz mechanism of anomaly cancellation. In this
paper we discuss possible solutions to this problem and comment about the fact
that the string-loop generated Fayet-Iliopoulos D-term may trigger the presence
of global and local cosmic strings at the end of inflation.


title:
Leptoquark explanation of HERA anomaly in the context of gauge
  unification

abstract:
  We examine the consequences of leptoquark explanation of HERA anomaly in the
context of R parity conserving supersymmetric gauge unified theory with the
gauge unification scale at $\sim 10^{16}$ GeV. We pointed out the difficulty of
constructing a grandunified theory. However gauge unification is still possible
at $\sim 10^{16}$ GeV when additional multiplets are introduced. We determine
the mass spectrum of these additional fields (fermions and scalars) in gauge
mediated and supergravity scenarios. Unique signatures and mass bounds are
discussed.


title:
Implications of the HERA Events for the R-Parity Breaking SUSY Signals
  at Tevatron

abstract:
  The favoured R-parity violating SUSY scenarios for the anomalous HERA events
correspond to top and charm squark production via the $\lambda'_{131}$ and
$\lambda'_{121}$ couplings. In both cases the corresponding electronic
branching fractions of the squarks are expected to be $\ll 1$. Consequently the
canonical leptoquark signature is incapable of probing these scenarios at the
Tevatron collider over most of the MSSM parameter space. We suggest alternative
signatures for probing them at Tevatron, which seem to be viable over the
entire range of MSSM parameters.


title: What Can We Learn From Polarized Structure Function Data?

abstract:
  We summarise the perturbative QCD analysis of the structure function data for
g_1 from longitudinally polarized deep inelastic scattering from proton,
deuteron and neutron targets, with particular emphasis on testing sum rules,
determining helicity fractions, and extracting the strong coupling from both
scaling violations and the Bjorken sum rule.


title: Virtual photon structure from jet production

abstract:
  Some aspects of extracting the information on the structure of virtual
photons from jet production in ep and e^+e^- collisions are discussed.


title: Regularisation of Supersymmetric Theories

abstract:
  We discuss issues that arise in the regularisation of supersymmetric
theories. (To appear in the book `Perspectives on Supersymmetry', World
Scientific, Editor G. Kane.)


title: Exponentiation of the Sum of Nonabelian Amplitudes

abstract:
  This paper contains an implicit assumption that the summand in eq. (4.2) for
different $n$'s commute. This paper should be replaced by hep-th/9804181 where
this assumption is removedand the result generalized.


title: CP Violation due to new Delta B =1 Amplitudes

abstract:
  We make a systematic analysis of the effects of new physics in the B decay
amplitudes on the CP asymmetries in neutral B decays. Although these are
expected to be smaller than new physics effects on the mixing amplitude, they
are easier to probe in some cases. The effects of new contributions to the
mixing amplitude are felt universally across all decay modes, whereas the
effects of new decay amplitudes could vary from mode to mode. In particular the
prediction that the CP asymmetries in the B decay modes with $b\to c\bar c s$,
$b \to c\bar c d$, $ b\to c \bar u d$ and $ b\to s \bar s s$ should all measure
the same quantity (sin(2\beta) in the Standard Model) could be violated.


title: P, C and Strong CP in Left-Right Supersymmetric Models

abstract:
  We systematically study the connection between P, C and strong CP in the
context of both non-supersymmetric and supersymmetric left-right theories. We
find that the solution to the strong CP problem requires both supersymmetry and
parity breaking scales to be around the weak scale.


title:
Cosmological Nucleosynthesis and Active-Sterile Neutrino Oscillations
  with Small Mass Differences: The Nonresonant Case

abstract:
  We study the nonresonant oscillations between left-handed electron neutrinos
nu_e and nonthermalized sterile neutrinos nu_s in the early Universe plasma.
The case when nu_s do not thermalize till 2 MeV and the oscillations become
effective after nu_e decoupling is discussed. The evolution of neutrino
ensembles was described numerically by integrating the kinetic equations for
the neutrino density matrix in momentum space. We have provided a detail
numerical study of the influence of the nonequilibrium nu_e - nu_s oscillations
on the primordial production of He-4. The exact kinetic approach enabled us to
calculate the effects of neutrino population depletion, the distortion of the
neutrino energy spectrum and the generation of neutrino-antineutrino asymmetry
on the kinetics of neutron-to-proton transitions during the primordial
nucleosynthesis epoch and correspondingly on the cosmological He-4 production.
  It was shown that the neutrino population depletion and spectrum distortion
play an important role. The asymmetry effect, in case the lepton asymmetry is
accepted initially equal to the baryon one, is proved to be negligible for the
discussed range of delta m^2. Constant helium contours in delta m^2 - theta
plain were obtained for small mass differences delta m^2 < 10^{-7} eV^2. More
precise cosmological constraints on mixing parameters were obtained.


title: Semi-Leptonic B Decay

abstract:
  The definitions and properties of elastic and inelastic Isgur-Wise form
factors are reviewed. The nature of the "missing" exclusive semi-leptonic decay
fraction is identified. The role that completeness sum rules play in relating
form factors, spectroscopy, and model building is outlined.


title:
Two Higgs Doublets Models and CP Violating Higgs Exchange in e+ e- -> t
  bar-t Z

abstract:
  Appreciable CP Asymmetries (~ 10%) can arise in the reaction e+ e- -> t bar-t
Z already at TREE-LEVEL in models with two Higgs doublets. For a neutral Higgs
particle, h, with a mass in the range 50 GeV < m_h < 400 GeV, it may be
possible to detect a 2-3 sigma CP-odd effect in e+ e- -> t bar-t Z in ~ 1-2
years of running of a future high energy e+e- collider with c.m. energies of ~
1-2 TeV and an integrated luminosity of 200-500 inverse fb.


title: Thermodynamic Gross-Neveu model under constant electromagnetic field

abstract:
  Analyzed is the effective potential of D-dimensional thermodynamic
Gross-Neveu model (defined by large-N leading order, $2\leq D<4$) under
constant electromagnetic field ($\vec{E}\cdot\vec{B}=0$). The potential is
derived from a thermal analogy of the worldline formalism. In the magnetic
case, the potential is expressed in terms of a discretized momentum sum instead
of a continuum momentum integral, and it reproduces known critical values of
$\mu$ and $T$ in the continuum limit. In the electric case, chiral symmetry is
restored at finite $T$ (with arbitrary $\mu$) against instability of fermion
vacuum. An electromagnetic duality is pointed out as well. Phase diagrams are
obtained in both cases.


title:
On Topological Susceptibility, Vacuum Energy and Theta Dependence in
  Gluodynamics

abstract:
  We suggest that the topological susceptibility in gluodynamics can be found
in terms of the gluon condensate using renormalizability and heavy fermion
representation of the anomaly. Analogous relations can be also obtained for
other zero momentum correlation functions involving the topological density
operator. Using these relations, we find the theta dependence of the
condensates <GG>, <G \tilde{G}> and of the partition function for small theta
and an arbitrary number of colors.


title: Dynamical Flavor Hierarchy and Heavy Top

abstract:
  In the Standard Model one of the generations is much heavier than the other
two. We propose a simple mechanism where all three generations are treated on
the equal footing to begin with, and one heavy and two light families emerge
from supersymmetric strong dynamics. The Yukawa mass matrix is identified with
vevs of the meson fields of some additional gauge theory. It is then forced to
have rank one (in the leading order) by non-perturbative superpotential.


title: The $p_T$ Distribution of $J/\psi$ in QGP

abstract:
  We consider the contributions of both color-singlet and octet $c\bar c$ bound
states for studying the suppression of $J/\psi$ production in quark gluon
plasma (QGP) and have found that the existence of the color-octet $c\bar c$ may
cause the $p_T-$distribution of $J/\psi$ a decrease with $p_T$ after a critical
value $(p_T)_{max}$, which is quite different from the behavior in Hadronic
Matter (HM).


title: QCD fits to ZEUS and fixed target structure function data

abstract:
  Preliminary results are presented on the gluon density obtained from a QCD
analysis of ZEUS and NMC F2 structure function data. Also given is an estimate
of the experimental error on the positron-proton NC Born cross-section at large
x and Q2.


title:
Comment on Vacuum Stability and Electroweak Baryogenesis in the MSSM
  with Light Stops

abstract:
  We show that, for all values of $Tan \beta$ and the light right-handed stop
mass for which the electroweak phase transition is strong enough to avoid
washout following electroweak baryogenesis, the electroweak vacuum is stable
over the lifetime of the observed Universe.
  Cosmological stability of the electroweak vacuum is violated only if the
light right-handed stop is lighter than 100-115GeV.


title: Pion-pion scattering at low energy

abstract:
  We present technical details of the evaluation of the elastic pi-pi
scattering amplitude to two loops in chiral perturbation theory. In particular,
we elaborate on the renormalization procedure at the two-loop order and on the
evaluation of the relevant Feynman diagrams that can all be expressed in terms
of elementary functions. For the sake of clarity, we discuss these matters both
in the N-component $\phi^4$ theory (in its symmetric phase) and in chiral
perturbation theory. Estimates for the relevant low-energy constants of
$O(p^6)$ are presented. Threshold parameters and phase shifts are then
calculated for two sets of $O(p^4)$ coupling constants and compared with
experiment. We comment on the extraction of threshold parameters from phase
shift data.


title: Future measurements of alpha_s and xg from scaling violations at HERA

abstract:
  Results are presented of a study of the experimental and theoretical accuracy
one may achieve at HERA in measuring the strong coupling constant alpha_s and
the gluon distribution from scaling violations of F2 structure functions.


title:
D^0-D^0(bar) mixing in the weak-gauged U(4)_L x U(4)_R Chiral Lagrangian
  Model

abstract:
  The D^0-D^0(bar) mixing is analyzed in a weak gauged U(4)_L x U(4)_R chiral
lagrangian model where the electroweak interaction is introduced as a gauge
theory over the meson degrees of freedom. This model allows a particular
realization of the G.I.M. mechanism and then could be useful in the study of
processes where G.I.M. suppression is effective. As a test of the model we have
also analyzed the K^0-K^0(bar) mixing. We find \Delta m_K in good agreement
with the experimental result and we show that the D^0-D^0(bar) mixing is very
much suppressed in agreement with previous estimates in the Heavy Quark
expansion framework.


title:
Thermal Relaxation Time in Chemically Non-equilibrated Quark- Gluon
  Plasma

abstract:
  The definition of thermal relaxation time is extended to chemically
non-equilibrated quark-gluon plasma and the chemical non-equilibrated thermal
relaxation times for partons are calculated using the non-equilibrium Debye
mass as the infrared regulator. The dependence of the thermal relaxation time
on the fugacity is given and the influence of the chemical non-equilibration is
discussed. We find that there are threshold fugacities $\lambda_g^*$ and
$\lambda_q^*$ for gluons and quarks. For \lambda_g < \lambda_g^* (\lambda_q <
\lambda_q^*), \tau_g^{NEQ}/\tau_g^{EQ} (\tau_q^{NEQ}/\tau_q^{EQ}) decreases
strongly with increasing fugacity, while for $\lambda_g > \lambda_g^*
(\lambda_q>\lambda_q^*$), the ratios are almost 1. It is shown that there is
also the two-stage equilibration in a chemically non-equilibrated plasma. We
also discussed the effect of using the non-equilibrium Deby mass as the
infrared cutoff.


title: The Theory of Heavy Baryons

abstract:
  I discuss the theory of heavy baryon spectroscopy, emphasizing predictions
which follow from light and heavy quark symmetries.


title: Initial Conditions for Supersymmetric Inflation

abstract:
  We perform a numerical investigation of the fields evolution in the
supersymmetric inflationary model based on radiative corrections. Supergravity
corrections are also included. We find that, out of all the examined initial
data, only about 10% give an adequate amount of inflation and can be considered
as ''natural''. Moreover, these successful initial conditions appear scattered
and more or less isolated.


title: Non-abelian flavour symmetry and R-parity

abstract:
  If R-parity violation turns out to be a true aspect of Nature, a speculation
about its possible origin could add a new dimension to the supersymmetric
flavour problem. It has been shown in the past by Barbieri, Hall and their
collaborators that the small breaking parameters of an approximate non-abelian
flavour symmetry could govern the light quark and lepton masses and at the same
time could account for the near degeneracies of squarks and sleptons. A
possible connection of the above feature to the natural suppressions of
R-parity-violating couplings has been investigated here. With some
modifications of the approximate flavour symmetry, a supersymmetric theory
without R-parity has been motivated that has testable experimental signatures.


title:
The electromagnetic gauge invariance in $SU(3)_L\otimes U(1)_N$ models
  of electroweak unification reexamined

abstract:
  Two models with $SU(3)_C\otimes SU(3)_L\otimes U(1)_N$ gauge symmetry are
considered. We show that the masslessness of the photon does not prevent the
neutrinos from acquiring Majorana masses. That is, there is no relation between
the VEVs of Higgs fields and the electromagnetic gauge invariance contrary to
what has been claimed recently.


title: Contact terms in charged current processes at HERA

abstract:
  We obtain bounds on the mass scales characterizing four-fermion contact
interactions in charged current processes. The bounds arise from the Q^2 and x
distributions in the processes e p -> \nu X measured by the two HERA
experiments, H1 and ZEUS.


title: Extracting $\alpha_S$ from TEVATRON data

abstract:
  In this contribution we explore one of the many possibilities of determining
the strong coupling constant $\alpha_S$ at hadron colliders. The method
considered is quite unique compared to other methods in that the value of
$\alpha_S$ is determined by the ``evolution rate'' of the parton density
functions rather than by the ``event rate''.


title:
QED Radiative Corrections to $Z$ Boson Production and the Forward
  Backward Asymmetry at Hadron Colliders

abstract:
  The ${\cal O}(\alpha)$ radiative corrections to the process
$p\,p\hskip-7pt\hbox{$^{^{(\!-\!)}}$} \rightarrow \gamma^*, \, Z \rightarrow
\ell^+ \ell^-$ ($\ell=e,\,\mu$) are calculated. Factorizing the collinear
singularity associated with initial state photon bremsstrahlung into the parton
distribution functions, we find that initial state corrections have a much
smaller effect than final state radiative corrections. Due to mass singular
logarithmic terms associated with photons emitted collinear with one of the
final state leptons, QED radiative corrections strongly affect the shape of the
di-lepton invariant mass distribution, the lepton transverse momentum spectrum,
and the forward backward asymmetry, $A_{FB}$. They lead to a sizeable shift in
the $Z$ boson mass extracted from data, decrease the di-lepton cross section by
up to 10\%, and increase the integrated forward backward asymmetry in the $Z$
peak region by about 7\% at the Tevatron. We also investigate how experimental
lepton identification requirements modify the effect of the QED corrections,
and study the prospects for a high precision measurement of
$\sin^2\theta^{lept}_{eff}$ using the forward backward asymmetry at the Large
Hadron Collider (LHC).


title:
Maximizing Hadron Collider Sensitivity to Gauge-Mediated Supersymmetry
  Breaking Models

abstract:
  We consider typical hadron collider detector signals sensitive to delayed
decays of the lightest neutralino to photon plus goldstino and demonstrate the
potential for substantially increasing the portion of the general parameter
space of a gauge-mediated supersymmetry breaking model that can be probed at
the Tevatron.


title: Extension of the Geometrical Two-Chain Model to high energies

abstract:
  In the paper the extension of the Geometrical Two-Chain model to higher
energies is presented. The agreement with experimental data is achieved using
pre-hadronization chain breakups due to coloured dipole radiation mechanism and
the discretization of the soft gluon emission process.


title: Non-Leptonic Decays of B Mesons and Strong Coupling Constants

abstract:
  Non-leptonic decays of B mesons into two mesons or meson resonances are
studied on the basis of two versions of simple pole-dominance models involving
scalar, vector, pseudoscalar and axial-vector poles. The results are compared
with those obtained from the usual factorization model and used to obtain
information on strong coupling constants between B meson and one light or one
charmed meson, respectively. These coupling constants are compared to results
from various QCD sum rule calculations.


title: Higher Threshold Parameters in pi pi Scattering

abstract:
  A family of threshold parameters which probe the stability of chiral
predictions is considered. The relevant criteria for the choice of threshold
parameters are discussed. Sum rules for these quantities are derived from
dispersion relations and evaluated from effective range formulae. Good
agreement with two-loop chiral estimates for many of these quantities is found
and interesting discrepancies are discussed.


title: Q-balls in the MSSM

abstract:
  Q-balls are generically present in models with softly broken low-energy
supersymmetry. We discuss the properties of these non-topological solitons,
which can precipitate a new kind of first-order phase transition in the early
Universe and have other important implications for cosmology and experiment.


title: Suppression of PiNN* Coupling and Chiral Symmetry

abstract:
  Meson-baryon couplings between positive and negative parity baryons are
investigated using two point correlation functions in the soft meson limit. We
find that the pi NN^* coupling vanishes due to chiral symmetry, while the eta
NN^* coupling remains finite. We perform an analysis based on the algebraic
method for SU(2) and SU(3) chiral symmetry, and find that baryon axial charges
play an essential role for vanishing coupling constants.


title: Anomalous J/Psi suppression and the nature of deconfinement

abstract:
  We study the characteristic features of J/Psi suppression by deconfinement. A
first order phase transition leads to an essentially discontinuous onset of
anomalous J/Psi suppression. The different energy densities required for the
dissociation of different charmonium states result in a two-step suppression
pattern, in which first the J/Psi's from chi decays are suppressed and
subsequently the directly produced J/Psi states. Combining both features leads
to a unique form of J/Psi suppression in a deconfining medium.


title: Next-to-Leading Order Calculation of Four-Jet Shape Variables

abstract:
  We present the next-to-leading order calculation of two four-jet event shape
variables, the D parameter and acoplanarity differential distributions. We find
large, more than 100% radiative corrections. The theoretical prediction for the
D parameter is compared to L3 data obtained at the Z peak and corrected to
hadron level.


title: Form factor description of the non-collinear Compton scattering tensor

abstract:
  We present a parameterization of the non-collinear (virtual) Compton
scattering tensor in terms of form factors, in which the Lorentz tensor
associated with each form factor possesses manifest electromagnetic gauge
invariance. The main finding is that in a well-defined form factor expansion of
the scattering tensor, the form factors are either symmetric or antisymmetric
under the exchange of two Mandelstam variables, $s$ and $u$. Our decomposition
can be used to organize complicated higher-order and higher-twist contributions
in the study of the virtual Compton scattering off the proton. Such procedures
are illustrated by use of the virtual Compton scattering off the lepton. In
passing, we note the general symmetry constraints on Ji's off-forward parton
distributions and Radyushkin's double distributions.


title: Superstring phenomenology -- present and future perspective

abstract:
  The objective of superstring phenomenology is to develop the models and
methodology needed to connect quantitatively between Planck scale physics and
electroweak scale experimental data. I review the present status of this
endeavor with a focus on the three generation free fermionic models.


title:
A Gauge Model for Extra Weak Bosons Implied by Compositeness of Quarks
  and Leptons

abstract:
  Properties of extra weak bosons are discussed in a gauge model based on
SU(2)_LXU(1)_YXSU(2)'_L. The physics of SU(2)'_L respects the duality in the
Higgs and confining phases, where massive gauge bosons in the Higgs phase are
equivalently represented by composite vector bosons in the confining phase
below the scale of SU(2)'_L . interactions for SU(2)'_L-singlet composites
induced in the confining phase can be generated by nonlinear interactions of
the four Fermi type respecting SU(2)_LXU(1)_Y, which create quarks, q_i^A
(A=r,g,b; i=1,2), leptons, l_i, vector bosons, V_mu^(a) (a=1,2,3) and the Higgs
scalar, phi, made by scalar subconstituents, c^{0,A}, and spinor
subconstituents, w_i,as q.l=cw, V=(w-{bar}w)_{J=1} and phi=(w-{bar}w)_{J=0} .
The physics described by these composites is equivalent to the one by
SU(2)_LXU(1)_YXSU(2)'_L below the confining scale.


title: Power Counting in Dimensionally Regularized NRQCD

abstract:
  We present a scheme for calculating in NRQCD with consistent power counting
in the heavy quark velocity v. As an example, we perform the systematic
matching of an external current onto NRQCD at subleading order in v, a
calculation relevant for the process e^+e^- -> hadrons near threshold.
Consistent velocity power counting in dimensional regularization is achieved by
including two distinct gluon fields, one corresponding to gluon radiation and
one corresponding to an instantaneous potential. In this scheme power counting
is manifest in any gauge, and also holds for non-gauge interactions. The
matching conditions for an external vector current in NRQCD are calculated to
O(g^2 v^2) and the cancellation of infrared divergences in the matching
conditions is shown to require both gluon fields. Some subtleties arising in
the matching conditions at subleading order are addressed.