title:
Angular Dependence of the Radiative Gluon Spectrum and the Energy Loss
  of Hard Jets in QCD Media

abstract:
  The induced momentum spectrum of soft gluons radiated from a high energy
quark propagating through a QCD medium is derived in the BDMPS formalism. A
calorimetric measurement for the medium dependent energy lost by a jet with
opening angle $\theta_{{\rm cone}}$ is proposed.The fraction of this energy
loss with respect to the integrated one appears to be the relevant
observable.It exhibits a universal behaviour in terms of the variable
$\theta^2_{{\rm cone}} L^3 \hat q$ where $L$ is the size of the medium and
$\hat q$ the transport coefficient. Phenomenological implications for the
differences between cold and hot QCD matter are discussed.


title:
Quark Dispersion Relation and Dilepton Production in the Quark-Gluon
  Plasma

abstract:
  Under very general assumptions we show that the quark dispersion relation in
the quark-gluon plasma is given by two collective branches, of which one has a
minimum at a non-vanishing momentum. This general feature of the quark
dispersion relation leads to structures (van Hove singularities, gaps) in the
low mass dilepton production rate, which might provide a unique signature for
the quark-gluon plasma formation in relativistic heavy ion collisions.


title:
Single transverse spin asymmetries for semi-inclusive pion production in
  DIS

abstract:
  We present a phenomenological approach to the description of single
transverse spin asymmetries (STSA) in inclusive hadron production. It
generalizes the pQCD formalism for high energies and large p_T inclusive hadron
production processes, A+B -> C+X, by incorporating quark intrinsic motion in
the spin dependent quark distribution and fragmentation functions. We
concentrate here on spin and k_T effects in the fragmentation process of a
polarized quark into the observed hadron, and give predictions for STSA in
semi-inclusive deep inelastic scattering, l + p -> pion + X and gamma^* + p ->
pion + X.


title: Memo on Extracting |V(cb)| and |V(ub)/V(cb)| from semileptonic B decays

abstract:
  Heavy Quark Expansions for semileptonic decays of beauty hadrons are briefly
reviewed. I analyze how $|V(cb)|$ can be extracted from the semileptonic width
of $B$ mesons, the average semileptonic width of all weakly decaying beauty
hadrons and from $B \ra l \nu D^*$ at zero recoil. Special attention is paid to
present theoretical uncertainties (including correlations among them) and on
how to reduce them in the future. Finally I will comment on theoretical
uncertainties in $|V(ub)/V(cb)|$.


title: Multibaryons with heavy flavors in the Skyrme model

abstract:
  We investigate the possible existence of multibaryons with heavy flavor
quantum numbers using the bound state approach to the topological soliton model
and the recently proposed approximation for multiskyrmion fields based on
rational maps. We use an effective interaction lagrangian which consistently
incorporates both chiral symmetry and the heavy quark symmetry including the
corrections up to order 1/m_Q. The model predicts some narrow heavy flavored
multibaryon states with baryon number four and seven.


title: On Neutrino Masses and Mixings from Extra Dimensions

abstract:
  In the framework of a Kaluza-Klein type theory with the Standard Model fields
localized on a 4-dimensional section while gravity propagates in a full
$4+\delta$-dimensional space-time, we examine a mechanism of naturally small
neutrino mass generation through couplings of Standard Model singlet fermion(s)
living also in the full space-time. A numerical studies is carried out on the
charged current universality constraint from the ratio of pion decay partial
widths. The bounds obtained on the fundamental mass scale could be stringent.


title: Equilibrium Distribution of Heavy Quarks in Fokker-Planck Dynamics

abstract:
  We obtain within Fokker-Planck dynamics an explicit generalization of
Einstein's relation between drag, diffusion and equilibrium distribution for a
spatially homogeneous system, considering both the transverse and longitudinal
diffusion for dimension n>1. We then provide a complete characterization of
when the equilibrium distribution becomes a Boltzmann/J"uttner distribution,
and when it satisfies the more general Tsallis distribution. We apply this
analysis to recent calculations of drag and diffusion of a charm quark in a
thermal plasma, and show that only a Tsallis distribution describes the
equilibrium distribution well. We also provide a practical recipe applicable to
highly relativistic plasmas, for determining both diffusion coefficients so
that a specific equilibrium distribution will arise for a given drag
coefficient.


title: No Spontaneous Breakdown of Chiral Symmetry in Nambu-Jona-Lasinio Model

abstract:
  We argue that the spontaneous breakdown of symmetry in the chirally symmetric
Nambu--Jona-Lasinio model which was supposed to illustrate the origin of the
low mass of pions in hadron physics does not occur due to strong fluctuations
in the sigma - pi field space. Although quarks acquire a constituent mass,
sigma and pi turn out to have equal heavy masses of the order of the
constituent quark mass.


title:
Neutrino mass patterns, R-parity violating supersymmetry and associated
  phenomenology

abstract:
  Motivated by the recent SuperKamiokande results on atmospheric neutrinos, we
incorporate massive neutrinos, with large angle oscillation between the second
and third generations, in a theory with R-parity violating supersymmetry. The
general features of such a theory are briefly reviewed. We emphasize its
testability through the observation of comparable numbers of muons and taus,
produced together with the W-boson, in decays of the lightest neutralino. A
distinctly measurable decay gap is another remarkable feature of such a
scenario.


title: One-loop analysis of the reaction pi N to pi pi N

abstract:
  Single pion production off nucleons is studied in the framework of heavy
baryon chiral perturbation theory to third order in the chiral expansion. Using
total and some older differential cross section data to pin down the low-energy
constants, most of the recent differential cross sections and angular
correlation functions can be described as well as total cross sections at
higher energies. We show that the contributions from the one loop graphs are
essentially negligible and that the dominant terms at second and third order
are related to pion-nucleon scattering graphs with one pion added. We also
discuss the possibility of extracting the pion-pion S-wave scattering lengths
from the unpolarized data.


title:
Measurement of CP Violation at the $\Upsilon(4S)$ without Time Ordering
  or $\Delta t$

abstract:
  I derive the expressions for the CP-violating asymmetry arising from
interference between mixed and direct decays in the Upsilon(4S) system, for the
case in which only one of the B decay times is observed, integrating over the
decay time of the other B. I observe that neither the difference of the decay
times Delta t, nor even their time-ordering, need be detected. A technique for
measurement of the CP-violating weak decay parameter sin(2beta) is described
which exploits this observation.


title: The flux-tube model of particle creation in nuclear collisions

abstract:
  I review some of the history of the flux-tube model, concentrating on work
done by the Los Alamos-Tel Aviv collaboration on particle creation and
back-reaction in uniform fields and in the central rapidity region. I discuss
the incorporation of more realistic geometry and structure of the flux tube via
application of the dual superconductor model of confinement.


title: Higgs pair production in the MSSM with explicit CP violation

abstract:
  In the minimal supersymmetric standard model with explicit CP violation,
associated production of the lightest Higgs boson with heavier ones is
analyzed. Due to explicit CP violation, the Higgs bosons are no longer CP
eigenstates so that both of the heavy Higgs bosons contribute to the process.
While the radiative corrections in the Higgs sector turn out to be quite
important, the vertex radiative corrections remain small as in the CP
conserving theory.


title:
Hadronization Corrections to Jet Cross Sections in Deep-Inelastic
  Scattering

abstract:
  The size of non-perturbative corrections to high E_T jet production in
deep-inelastic scattering is reviewed. Based on predictions from fragmentation
models, hadronization corrections for different jet definitions are compared
and the model dependence as well as the dependence on model parameters is
investigated. To test whether these hadronization corrections can be applied to
next-to-leading order (NLO) calculations, jet properties and topologies in
different parton cascade models are compared to those in NLO. The size of the
uncertainties in estimating the hadronization corrections is compared to the
uncertainties of perturbative predictions. It is shown that for the inclusive
k_\perp ordered jet clustering algorithm the hadronization corrections are
smallest and their uncertainties are of the same size as the uncertainties of
perturbative NLO predictions.


title: Color Neutrality and the Gluon Distribution in a Very Large Nucleus

abstract:
  We improve the McLerran-Venugopalan model for the gluon distribution
functions in very large nuclei by imposing the condition that the nucleons
should be color neutral. We find that enforcing color neutrality cures the
infrared divergences in the transverse coordinates which are present in the
McLerran-Venugopalan model. Since we obtain well-defined expressions for the
distribution functions, we are able to draw unambiguous conclusions about
various features of the model. In particular, we show that the gluon
distribution functions in the absence of quantum corrections behave as 1/x to
all orders in the coupling constant. Furthermore, our distribution functions
exhibit saturation at small transverse momenta. The normalization of the
distribution function we obtain is not arbitrary but specified in terms of the
nucleon structure. We derive a sum rule for the integral of the gluon
distribution function over transverse momenta, and show that the non-Abelian
contributions serve only to modify the shape of the transverse momentum
distribution. We obtain a relatively simple expression for the mean value of
the transverse momentum-squared. The connection between the
McLerran-Venugopalan model and the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi
equation is discussed quantitatively. Finally, we illustrate our results in
terms of a simple nuclear model due to Kovchegov.


title:
Comment on "New Experimental Limit for the Electric Dipole Moment of the
  Neutron"

abstract:
  A new limit for the neutron electric dipole moment has been recently
reported. This new limit is obtained by combining the result from a previous
experiment with the result from a more recent experiment that has much worse
statistical accuracy. We show that the old result has a systematic error
possibly four times greater than the new limit, and under the circumstances,
averaging of the old and new results is statistically invalid. The conclusion
is that it would be more appropriate to quote two independent but mutually
supportive limits as obtained from each experiment separately.


title: On the role of $a_1(1260)$ meson in the $\tau\to 4\pi\nu_{\tau}$ decay

abstract:
  We demonstrate that a simple model successfully describing experimental data
for the process $\epm\to 4\pi$ can also qualitatively account for the data of
CLEOII and ALEPH obtained recently for the decay $\tau\to 4\pi\nu_{\tau}$. The
model is based on the assumption of the $a_1(1260)\pi$ and $\omega\pi$
dominance as intermediate states. Our observation is in contrast with the claim
by ARGUS that the $\rho$-meson signal in the $\tau\to 4\pi\nu_\tau$ decay can
not be explained by the $a_1\pi$ intermediate state.


title: Rare kaon decays

abstract:
  We review some recent theoretical results on rare kaon decays. Particular
attention is devoted to establish the short distance (direct CP violating)
contribution to K_L => \pi^0 e \bar{e}. This is achieved by a careful study of
the long distance part. As byproduct, we discuss interesting chiral tests.


title: Gluons in a Color-Neutral Nucleus

abstract:
  We improve the McLerran-Venugopalan model by introducing a charge-density
correlation function which is consistent with the observation that nucleons
carry no net color charge. The infrared divergence in the transverse
coordinates that was present in the McLerran-Venugoplan model is eliminated by
the enforcement of color neutrality.


title: Charmonium suppression in p-A collisions

abstract:
  The new high precision data on charmonium production in proton-nucleus
collisions by the E866/NuSea collaboration at Fermilab allow - together with
older data at lower energies - to fix a unique set of parameters for the
standard production and absorption scenario of charmonium in a proton-nucleus
reaction. In this scenario the c-cbar pair is formed in an octet state, emits a
gluon and continues its radial expansion in a singlet state until it has
reached the charmonium radius. In all three phases it can interact with the
nuclear environment. We find that the lifetime of the octet state is much
shorter than acceptable on physical grounds. This challenges the physical
reality of the first phase in the standard scenario.


title: Free Energy of a Hot Gluon Plasma and hard-thermal-loop Resummation

abstract:
  In this talk I briefly discuss the thermodynamics of the quark-gluon plasma
The calculation of the free energy of a hot gluon plasma to leading order in
hard-thermal-loop perturbation theory is outlined. The HTL free energy is
compared with the weak-coupling expansion and lattice results.


title: Sound in relativistic superfluid with vorticity

abstract:
  We develope a theory of sound in a relativistic superfluid with quantum
vortices. The vortices are presented by vortex fluid. For a particular
separable model we find new modes of which a non-relativistic superfluid is
deprived.


title: Stopped Muon Decay Lifetime Shifts due to Condensed Matter

abstract:
  Up to second order in alpha, vacuum electro-magnetic corrections to weak
interaction induced charged particle lifetimes have been previously studied. In
the laboratory, stopped muon lifetimes are measured in a condensed matter
medium whose radiation impedance differs from that of the vacuum. The resulting
condensed matter corrections to first order in $\alpha $ dominate those vacuum
radiative corrections (two photon loops) which are second order in alpha.


title: Decoupling of Massive Right-handed Neutrinos

abstract:
  We investigate the effect of B+L - violating anomalous generation of massive
right-handed neutrinos on their decoupling, when the right-handed neutrino mass
is considerably greater than the right-handed gauge boson masses. Considering
normal annihilation channels, the Lee-Weinberg type of calculation, in this
case, gives an upper bound of about 700 Gev, which casts doubt on the existence
of such a right-handed neutrino mass greater than right-handed gauge boson
masses. We examine the possibility that a consideration of anomalous effects
related to the SU(2)_R gauge group may turn this into a lower bound of the
order of 100 Tev.


title:
H(SUSY)->tau+tau->hadron+hadron channel, its advantages and potential
  instrumental drawbacks

abstract:
  We present a first study of the channel H, A -> tau+tau -> h+ + h- + X in CMS
at high m(A) values where no triggering difficulties are expected with QCD
jets. At present the tau selection is based solely on the presence of a hard
isolated track in the "tau" jet, but further refinements based on calorimeter
collimation or impact parameter selections are obviously possible. The main
irreducible background in these conditions is due to QCD jets with hard
fragmentations. A large reduction of this background and improvement in the
expected signal to background ratio is provided by Etmiss cuts. The expected
high-mass reach in the m(A) tan(beta) parameter space for 3 x 10**4pb**-1 is
shown. This H -> tau+tau channel provides the highest mass reach and the best
mass resolution when compared to tau,tau -> lepton+hadron + Xand tau,tau ->
electton + muon + X final states. To the extent that with further calorimetric
and impact parameter based selection criteria the QCD background can be kept
under control, i.e. below the irreducible Z,gamma* -> tau+tau background, we
should strive to have a first level trigger allowing to explore the mass range
down to ~ 150 - 200 GeV.


title:
Condensation of a Strongly Interacting Parton Plasma into a Hadron Gas
  in High Energy Nuclear Collisions

abstract:
  We examine the effects of color screening on the transition of a parton
plasma into a hadron gas at RHIC energies. It is found that as expected, color
screening posed itself as a significant barrier for hadronization.
Parton-hadron conversion would therefore be delayed and prolonged when compared
to that occuring in a vacuum. Due to the on-going expansion, the resulting
hadron densities are lowered. Parton equilibration is also shown to be
seriously disrupted in the process.


title: Effective Mass Scale of New Physics in the Absence of the Higgs Boson

abstract:
  We consider a hypothetical scenario in which the Higgs boson is absent, and
attempt to constrain the mass scale Lambda of the new physics that would take
its place. Using recent measurements of sin^2(theta_eff^lept) and M_W, we show
that, in a class of theories characterized by simple conditions, the upper
bound on Lambda is close to or smaller than the SM upper bound on M_H, while in
the complementary class Lambda is not restricted by our considerations. The
issue of fine-tuning when Lambda is large is briefly discussed. As a by-product
of our considerations, we discuss the usefulness and important properties of a
radiative correction, Delta r_eff, that directly links sin^2(theta_eff^lept)
with alpha, G_mu, and M_Z.


title: The electroweak chiral Lagrangian reanalyzed

abstract:
  In this paper we reanalyze the electroweak chiral Lagrangian with particular
focus on two issues related to gauge invariance. Our analysis is based on a
manifestly gauge-invariant approach that we introduced recently. It deals with
gauge-invariant Green's functions and provides a method to evaluate the
corresponding generating functional without fixing the gauge. First we show,
for the case where no fermions are included in the effective Lagrangian, that
the set of low-energy constants currently used in the literature is redundant.
In particular, by employing the equations of motion for the gauge fields one
can choose to remove two low-energy constants which contribute to the
self-energies of the gauge bosons. If fermions are included in the effective
field theory analysis the situation is more involved. Even in this case,
however, these contributions to the self-energies of the gauge bosons can be
removed. The relation of this result to the experimentally determined values
for the oblique parameters S, T, and U is discussed. In the second part of the
paper we consider the matching relation between a full and an effective theory.
We show how the low-energy constants of the effective Lagrangian can be
determined by matching gauge-invariant Green's functions in both theories. As
an application we explicitly evaluate the low-energy constants for the standard
model with a heavy Higgs boson. The matching at the one-loop level and at
next-to-leading order in the low-energy expansion is performed employing
functional methods.


title: Elements of Supersymmetry

abstract:
  These notes are intended to provide an introduction to supersymmetry. The
notes begin with supersymmetric quantum mechanics and the basic properties of
spinor fields. The supersymmetry of simple theories of spin-zero and
spin-one-half fields is discussed with emphasis upon the charges that generate
the transformations of supersymmetry. Abelian and non-abelian supersymmetric
gauge theories are characterized in their simpler and more general forms.
Superfields are defined, and the concise notation they make possible is
described. The minimal supersymmetric standard model is discussed with
particular attention to the Higgs fields and the electro-weak superpotential.


title: Lepton Mixing: Small, Large, Maximal?

abstract:
  The SuperKamiokande data on atmospheric neutrinos imply that $\nu_{\mu}$ has
large (or even maximal) mixing. It is still open question whether this mixing
is the flavor one or mixing with singlet state (sterile neutrino). Several
tests exist to establish the channel of atmospheric neutrino oscillations.
Large mixing can be a property of the second and third generations, so that the
scheme with single large mixing is realized. It can be a generic property of
all leptons, thus leading to the bi-large or threefold large mixing schemes.
The ambiguity will be resolved by identification of solution of the solar
neutrino problem. In this review we consider phenomenology of various mixing
schemes. The key measurements which will allow us to make significant step in
reconstruction of the neutrino mass and flavor spectrum are discussed.


title:
On the phenomenological analyses of $s$-${\bar s}$ asymmetry in the
  nucleon sea

abstract:
  Two phenomenological models which give opposite predictions for the
$s$-${\bar s}$ asymmetry in the nucleon sea are re-analyzed carefully. It is
pointed out that although the quantitative results in both models depend
dramatically on the parameters, the predictions for the shape of $s(x)-{\bar
s}(x)$ in the two models are parameter independent and opposite. Thereby the
coming experiments are likely to be able to distinguish the two models. We find
that the reason for the two models giving opposite predictions is that the
fluctuation functions and parametrizations for the strange (anti-strange) quark
distribution in the baryon (meson) in the two models are quite different. To
further investigate these models, we use the same parametrizations for the
strange (anti-strange) distributions of the baryon (meson) in the two models.
We find that one of the models depends strongly on the parameter which controls
the behavior of the meson-baryon fluctuation function. Also the two models
agree on the shape and size of $s$-${\bar s}$ for some values of the model
parameters, but can disagree strongly for others.


title: LABSMC: Monte Carlo event generator for large-angle Bhabha scattering

abstract:
  A Monte Carlo event generator is presented. An original algorithm is
developed to simulate electron-positron scattering at energies and momentum
transferred much more than the electron mass. The first-order electroweak
radiative corrections are included completely. Higher order corrections are
taken into account by means of electron structure functions.


title: Jet Production by Virtual Photons

abstract:
  The production of jets is studied in collisions of virtual photons, gamma*-p
and gamma*-gamma*, specifically for applications at HERA and LEP2. Photon flux
factors are convoluted with matrix elements involving either direct or resolved
photons and, for the latter, with parton distributions of the photon. Special
emphasis is put on the range of uncertainty in the modeling of the resolved
component. The resulting model is compared with existing data.


title: The hypothesis of a real Cabibbo Kobayashi Maskawa matrix

abstract:
  The hypothesis of a real Cabibbo-Kobayashi-Maskawa matrix has been considered
and found to be disfavoured by present measurements even when neglecting
results from CP violation in neutral Kaon decay. The Best Linear Unbiased
Estimator has been used as a statistical approach to compute the Confidence
Level. A new way to take into account the information from Bs mesons
oscillations has been considered, reducing considerably the error on
extractions of rho and eta parameter of the Wolfenstain parametrization of the
matrix.


title: Probing the nucleon at large momentum tramsfer

abstract:
  The central role of soft nucleon matrix elements in reactions of high energy
electrons or real photons with nucleons is emphasized. These soft matrix
elements are described in terms of skewed parton distributions. Their
connections to ordinary parton distributions, form factors, Compton scattering
and hard meson electroproduction is discussed.


title:
New effects observed in central production by experiment WA102 at the
  CERN Omega Spectrometer

abstract:
  A partial wave analysis of the centrally produced KK and pipi systems shows
that the fJ(1710) has J = 0. In addition, a study of central meson production
as a function of the difference in transverse momentum (dPT) of the exchanged
particles shows that undisputed qqbar mesons are suppressed at small dPT
whereas the glueball candidates are enhanced and that the production cross
section for different resonances depends strongly on the azimuthal angle
between the two outgoing protons.


title: Cumulative particle production as a rare event

abstract:
  The generalization of the Glauber formula for cumulative production events is
derived. On its basis the multiplicity distribution in such events is related
to the one in the minimum bias events. As compared to the rare events of type
$C$, the formula involves a shift in the arguments determined by the
multiplicity from a collision with a cluster of several nucleons.


title: Conformal string operators and skewed parton distributions

abstract:
  We discuss skewed parton distributions in the coordinate space. Solution of
the corresponding LO evolution equation is constructed in terms of
eigenfunctions of the evolution kernel and its relation to the conformal
symmetry is explained.


title:
Vector Boson Pair Production in Hadronic Collisions at Order $\alpha_s$:
  Lepton Correlations and Anomalous Couplings

abstract:
  We present cross sections for production of electroweak vector boson pairs,
$WW$, $WZ$ and $ZZ$, in $p\bar{p}$ and $pp$ collisions, at next-to-leading
order in $\alpha_s$. We treat the leptonic decays of the bosons in the
narrow-width approximation, but retain all spin information via decay angle
correlations. We also include the effects of $WWZ$ and $WW\gamma$ anomalous
couplings.


title:
Extending the Standard Model: an upper bound for a neutrino mass from
  the rare decay K+ -> Pi+ neutrino antineutrino

abstract:
  The standard model seeming at a loss to account for the present experimental
average rate for the rare decay K+ -> Pi+ neutrino antineutrino, I tackle the
question with the extension of the Glashow-Salam-Weinberg model to an SU(2)left
x U(1) gauge theory of J=0 mesons proposed by the author in [Phys. Lett. B 385
(1996) 198], in which, in addition, the neutrinos are given Dirac masses from
Yukawa couplings to the Higgs boson. The latter triggers a new contribution to
this decay through flavor changing neutral currents that arise in the quartic
term of the symmetry breaking potential; it becomes sizeable for a neutrino
mass in the $MeV$ range; the experimental upper limit for the decay rate
translates into an upper bound of 5.5 MeV for the mass of the neutrino, three
times lower than present direct bounds.


title: Progress in $K\to\pi\pi$ Decays

abstract:
  Recent work by J.~Prades and myself on $K\to\pi\pi$ is described. The first
part describes our method to connect in a systematic fashion the short-distance
evolution with long-distance matrix-element calculations taking the scheme
dependence of the short-distance evolution into account correctly. In the
second part I show the results we obtain for the $\Delta I=1/2$ rule in the
chiral limit.


title: Coherent States in High-Energy Physics

abstract:
  The amplitude for emitting $n$ bosons factorizes into the product of $n$
single-boson emission amplitudes, if the source is energetic and abelian. If it
is energetic but {\it non-abelian}, the amplitude is given by a sum of
factorized {\it quasi-particle} amplitudes. A quasi-particle is made up of an
arbitrary number of bosons, but couples to the source like a single one.
Factorization is related to coherence, and it allows computation of subleading
contributions not obtainable by usual means. Its importance is illustrated in
two applications: to solve the baryon problem in large-$N_c$ QCD, and to obtain
a total cross section satisfying the Froissart bound.


title: Transverse Momentum Transfer and Low x Parton Dynamics at HERA

abstract:
  The transverse momentum transfer correlation is introduced as a sensitive
probe that can be used to discriminate between models for parton dynamics in
low-x deep-inelastic scattering. Expectations for uncorrelated models and
models with short-range or long-range correlations are discussed and confronted
to results obtained from the LEPTO and ARIADNE Monte Carlo simulations
programmes.


title:
The NNLO QCD analysis ofthe CCFR data for $xF_3$: $Q^2$-dependence of
  the parameters

abstract:
  We continue the systematic next-to-next-to-leading order (NNLO) QCD analysis
of the CCFR data for $xF_3$ SF. The NNLO results forthe $Q^2$-dependence of the
parameters, which describe the $x$-dependence of this SF, are presented.


title: Looking for New Physics in Bd-Bd(bar) Mixing

abstract:
  There are variety of methods which directly test for the presence of new
physics in the b -> s flavour-changing neutral current (FCNC), but none which
cleanly probe new physics in the b -> d FCNC. One possible idea is to compare
the weak phase of the t-quark contribution to the b -> d penguin, which is
$-\beta$ in the SM, with that of Bd-Bd(bar) mixing ($-2\beta$ in the SM). In
this talk I show that, in fact, it is impossible to measure the weak phase of
the t-quark penguin, or indeed any penguin contribution, without theoretical
input. However, if one makes a single assumption involving the hadronic
parameters, it is possible to obtain the weak phase. I discuss how one can
apply such an assumption to the time-dependent decays $Bd(t) -> K0 K0(bar)$ and
$Bs(t) -> \phi K_s$ in order to detect new physics in the b -> d FCNC.


title:
QCD critical point and event-by-event fluctuations in heavy ion
  collisions

abstract:
  A summary of work done in collaboration with K. Rajagopal and E. Shuryak. We
show how heavy ion collision experiments, in particular, event-by-event
fluctuation measurements, can lead to the discovery of the critical point on
the phase diagram of QCD.


title: Chiral Phase Transition for SU(N) Gauge Theories

abstract:
  We describe the chiral phase transition for vector-like SU(N) gauge theories
as a function of the number of quark flavors Nf by making use of an
anomaly-induced effective potential. The potential depends explicitly on the
full beta-function and the anomalous dimension \gamma of the quark mass
operator. By using this potential we argue that chiral symmetry is restored for
\gamma <1. A perturbative computation of \gamma then leads to an estimate of
the critical value Nf^c for the transition.


title: Triangular Textures for Quark Mass Matrices

abstract:
  The hierarchical quark masses and small mixing angles are shown to lead to a
simple triangular form for the U- and D-type quark mass matrices. In the basis
where one of the matrices is diagonal, each matrix element of the other is, to
a good approximation, the product of a quark mass and a CKM matrix element. The
physical content of a general mass matrix can be easily deciphered in its
triangular form. This parameterization could serve as a useful starting point
for model building. Examples of mass textures are analyzed using this method.


title: Higher-Order Effects on Inelastic J/psi Photoproduction

abstract:
  Approximately taking into account the higher-order effects due to
multiple-gluon initial-state radiation, we extract from the latest Tevatron
data of prompt J/psi hadroproduction the leading colour-octet matrix elements
within the nonrelativistic-QCD (NRQCD) factorization formalism. We find that
the matrix elements which describe the formation of J/psi mesons from
colour-octet c c-bar pairs in the angular-momentum states (2S+1)^L_J = 1^S_0
and 3^P_J, with J = 0, 1, 2, which are responsible for the excess of the
predicted cross section of inelastic J/psi photoproduction over the existing
HERA data at high values of the inelasticity variable z, are significantly
reduced. As a consequence, the Tevatron and HERA measurements of inclusive
J/psi production are reconciled in the NRQCD framework.


title: Neutrinoless Double Beta Decay in Gauge Theories

abstract:
  Neutrinoless double beta decay is a very important process both from the
particle and nuclear physics point of view. Its observation will severely
constrain the existing models and signal that the neutrinos are massive
Majorana particles. From the elementary particle point of view it pops up in
almost every model. In addition to the traditional mechanisms, like the
neutrino mass, the admixture of right handed currents etc, it may occur due to
the R-parity violating supersymmetric (SUSY) interactions. From the nuclear
physics point of view it is challenging, because: 1) The relevant nuclei have
complicated nuclear structure. 2) The energetically allowed transitions are
exhaust a small part of all the strength. 3) One must cope with the short
distance behavior of the transition operators, especially when the intermediate
particles are heavy (eg in SUSY models). Thus novel effects, like the double
beta decay of pions in flight between nucleons, have to be considered. 4) The
intermediate momenta involved are about 100 MeV. Thus one has to take into
account possible momentum dependent terms in the nucleon current. We find that,
for the mass mechanism, such modifications of the nucleon current for light
neutrinos reduce the nuclear matrix elements by about 25 per cent, almost
regardless of the nuclear model. In the case of heavy neutrinos the effect is
much larger and model dependent.
  Taking the above effects into account, the available nuclear matrix elements
for the experimentally interesting nuclei A = 76, 82, 96, 100, 116, 128, 130,
136 and 150 and the experimental limits on the life times we have extracted new
stringent limits on the average neutrino mass and on the R-parity violating
coupling for various SUSY models.


title: The $x_F$ Dependence of $\psi$ and Drell-Yan Production

abstract:
  We discuss the nuclear dependence of $\psi$ and $\psi'$ production in
hadron-nucleus interactions as a function of longitudinal momentum fraction
$x_F$. Nuclear effects such as final-state absorption, interactions with
comovers, shadowing of parton distributions, energy loss, and intrinsic
heavy-quark components are described separately and incorporated into the model
which is then compared to the preliminary E866 data. The resulting nuclear
dependence of Drell-Yan production at 800 GeV and proposed measurements of
$\psi$, $\psi'$ and Drell-Yan production at 120 GeV are also calculated.


title: Semi-perturbative unification with extra vector-like families

abstract:
  We make a comprehensive analysis of an extended supersymmetric model(ESSM)
obtained by adding a pair of vector-like families to the minimal supersymmetric
standard model and having specific forms of 5 x 5 fermion mass matrices. The
singlet Higgs couplings which link the ordinary to vector-like generations do
not have the renormalization effects of the gauge interactions and hence the
"quasi-infrared fixed point" near the scale of the top quark mass. The two-loop
Yukawa effects on gauge couplings lead to an unified coupling $\alpha_X$ around
0.2 with an unification scale M_X of 10^{16.9} GeV. Large Yukawa effects in the
high energy region arrest the growth of the QCD coupling near M_X making the
evolution flat. The renormalization effects of the vector-like generations on
soft mass parameters has important effects on the charge and color
breaking(CCB)minima. We will show that there exists parameter space where there
is no charge and color breaking. We will also demonstrate that there exists
minima of the Higgs potential which satisfies the mass of the Z boson but avoid
CCB. Upper limits on the mass of the lightest Higgs boson from the one-loop
effective scalar potential is obtained for sets of universal soft supersymmetry
breaking mass parameters.


title:
Supernatural Supersymmetry: Phenomenological Implications of
  Anomaly-Mediated Supersymmetry Breaking

abstract:
  We discuss the phenomenology of supersymmetric models in which supersymmetry
breaking terms are induced by the super-Weyl anomaly. Such a scenario is
envisioned to arise when supersymmetry breaking takes place in another world,
i.e., on another brane. We review the anomaly-mediated framework and study in
detail the minimal anomaly-mediated model parametrized by only 3+1 parameters:
M_aux, m_0, \tan\beta, and sign(\mu). The renormalization group equations
exhibit a novel "focus point" (as opposed to fixed point) behavior, which
allows squark and slepton masses to be far above their usual naturalness
bounds. We present the superparticle spectrum and highlight several
implications for high energy colliders. Three lightest supersymmetric particle
(LSP) candidates exist: the Wino, the stau, and the tau sneutrino. For the Wino
LSP scenario, light Wino triplets with the smallest possible mass splittings
are preferred; such Winos are within reach of Run II Tevatron searches.
Finally, we study a variety of sensitive low energy probes, including b -> s
gamma, the anomalous magnetic moment of the muon, and the electric dipole
moments of the electron and neutron.


title: Parton Branching in Color Mutation Model

abstract:
  The soft production problem in hadronic collisions as described in the
eikonal color mutation branching model is improved in the way that the initial
parton distribution is treated. Furry branching of the partons is considered as
a means of describing the nonperturbative process of parton reproduction in
soft interaction. The values of all the moments, <n> and $C_q$, for q=2,...,5,
as well as their energy dependences can be correctly determined by the use of
only two parameters.


title: Large N_c Expansion in Chiral Quark Model of Mesons

abstract:
  We study SU(3)$_L\timesSU(3)_R$ chiral quark model of mesons up to the next
to leading order of $1/N_c$ expansion. Composite vector and axial-vector mesons
resonances are introduced via non-linear realization of chiral SU(3) and vector
meson dominant. Effects of one-loop graphs of pseudoscalar, vector and
axial-vector mesons is calculated systematically and the significant results
are obtained. We also investigate correction of quark-gluon coupling and
relationship between chiral quark model and QCD sum rules. Up to powers four of
derivatives, chiral effective lagrangian of mesons is derived and evaluated to
the next to leading order of $1/N_c$. Low energy limit of the model is
examined. Ten low energy coupling constants $L_i(i=1,2,...,10)$ in ChPT are
obtained and agree with ChPT well.


title:
Production and Equilibration of the Quark-Gluon Plasma with
  Chromoelectric Field and Minijets

abstract:
  Production and equilibration of quark-gluon plasma are studied within the
color flux-tube model, at the RHIC and LHC energies. Non-Abelian relativistic
transport equations for quarks, antiquarks and gluons, are solved in the
extended phase space which includes coordinates, momenta and color. Before the
chromoelectric field is formed, hard and semihard partons are produced via
minijets which provide the initial conditions necessary to solve the transport
equations. The model predicts that in spite of the vast difference between the
RHIC and LHC incident energies, once the local equilibrium is reached, the
energy densities, the number densities and the temperatures at the two machines
may not be very different from each other. The minijet input significantly
alters the evolution of the deconfined matter, unless the color field is too
strong. For the input parameters used here the equilibration time is estimated
to be $\sim 1$ fm at RHIC and $\sim 0.5$ fm at LHC, measured from the instant
when the two colliding nuclei have just passed through each other. The
temperature at equilibration is found to be $\sim 250$ MeV at RHIC and $\sim
300$ MeV at LHC.


title: Baryon form factors: Model-independent results

abstract:
  Baryon form factors can be analyzed in a largely model-independent fashion in
terms of two complementary approaches. These are chiral perturbation theory and
dispersion relations. I review the status of dispersive calculations of the
nucleon electromagnetic form factors in the light of new data. Then, I present
the leading one-loop chiral perturbation theory analysis of the hyperon and the
strange nucleon form factors. Open problems and challenges are also discussed.


title: Hadron yields in Au+Au/Pb+Pb at RHIC and LHC from thermalized minijets

abstract:
  We calculate the yields of a variety of hadrons for RHIC and LHC energies
assuming thermodynamical equilibration of the produced minijets, and using as
input results from pQCD for the energy densities at midrapidity. In the
calculation of the production of partons and of transverse energy one has to
account for nuclear shadowing. By using two parametrizations for the gluon
shadowing one derives energy densities differing strongly in magnitude. In this
publication we link those perturbatively calculated energy densities of partons
via entropy conservation in an ideal fluid to the hadron multiplicities at
chemical freeze-out.


title: Space-time properties of the higher twist amplitudes

abstract:
  A consistent and intuitive description of the twist-4 corrections to the
hadron structure functions is presented in a QCD-improved parton model using
time-ordered perturbative theory, where the collinear singularities are
naturally eliminated. We identify the special propagators with the backward
propagators of partons in time order.


title:
QCD and SUSY-QCD corrections to the Three-Body Decay of the Charged
  Higgs Boson

abstract:
  The ${\cal O}(\alpha_s)$ QCD corrections to the three-body decay width of the
charged Higgs $\Gamma$($H^+\to W^+b\bar{b}$) are discussed in the MSSM model.
Our calculations indicate that the standard QCD corrections to the three-body
decay mode raise the width by about 12% and the supersymmetric QCD
corrections(due to $\tilde{g}, \tilde{t}, \tilde{b}$ exchanges) can be
comparable to or even larger than the standard QCD corrctions in some regions
of the supersymmetric parameter space. This is mainly due to the effect of
large left-right mixing of stop($\tilde{t}$). It could significantly affect the
phenomenology of the $H^+$ search.


title: Algebraic reduction of one-loop Feynman graph amplitudes

abstract:
  An algorithm for the reduction of one-loop n-point tensor integrals to basic
integrals is proposed. We transform tensor integrals to scalar integrals with
shifted dimension and reduce these by recurrence relations to integrals in
generic dimension. Also the integration-by-parts method is used to reduce
indices (powers of scalar propagators) of the scalar diagrams. The obtained
recurrence relations for one-loop integrals are explicitly evaluated for 5- and
6-point functions. In the latter case the corresponding Gram determinant
vanishes identically for d=4, which greatly simplifies the application of the
recurrence relations.


title: Lepton-flavor violating decays as probes of quantum gravity?

abstract:
  Lepton flavor violating decays $Z \to \mu \tau$ and $J/\Psi, \Upsilon \to \mu
\tau$ are considered. It is shown that these decays can reach sizeable
magnitudes if some specific lepton-flavor violating 4-fermion operators are
generated by low scale quantum gravity effects, or by some other new physics at
a TeV scale.


title: B -> Xs l+ l- in SUSY

abstract:
  We study the semileptonic decays B -> Xs e+ e-, B -> Xs mu+ mu- in generic
supersymmetric extensions of the Standard Model. SUSY effects are parameterized
using the mass insertion approximation formalism and differences with MSSM
results are pointed out. Constraints on SUSY contributions coming from other
processes (e.g. b -> s gamma) are taken into account. Chargino and gluino
contributions to photon and Z-mediated decays are computed and non-perturbative
corrections are considered. We find that the integrated branching ratios and
the asymmetries can be strongly modified. Moreover, the behavior of the
differential Forward-Backward asymmetry remarkably changes with respect to the
Standard Model expectation.


title:
A new modified Altarelli-Parisi evolution equation with parton
  recombination in proton

abstract:
  The coefficients of the nonlinear terms in a modified Altarelli-Parisi
evolution equation with parton recombination are determined in the leading
logarithmic ($Q^2$) approximation. The results are valid in the whole $x$
region and contain the translation $GG\to q\bar q$, which is inhibited in the
double leading logarithmic approximation. The comparisons of the new evolution
equation with the Gribov-Levin-Ryskin equation are presented.


title: D-term Spectroscopy in Realistic Heterotic-String Models

abstract:
  The emergence of free fermionic string models with solely the MSSM charged
spectrum below the string scale provides further evidence to the assertion that
the true string vacuum is connected to the Z_2 x Z_2 orbifold in the vicinity
of the free fermionic point in the Narain moduli space. An important property
of the Z_2 x Z_2 orbifold is the cyclic permutation symmetry between the three
twisted sectors. If preserved in the three generations models the cyclic
permutation symmetry results in a family universal anomalous U(1)_A, which is
instrumental in explaining squark degeneracy, provided that the dominant
component of supersymmetry breaking arises from the U(1)_A D-term.
Interestingly, the contribution of the family--universal D_A-term to the squark
masses may be intra-family non-universal, and may differ from the usual
(universal) boundary conditions assumed in the MSSM. We contemplate how
D_A--term spectroscopy may be instrumental in studying superstring models
irrespective of our ignorance of the details of supersymmetry breaking. We
examine the possible effect of the intra--family non--universality on the
resulting SUSY spectrum and the values of the strong coupling, effective weak
mixing angle and W-gauge boson mass, up to a two loop accuracy, in the two
models (universal and non-universal). We find that non universality relaxes the
constraint of color and charge breaking minima which appears in the universal
case. In addition, it predicts a 3% smaller value of \alpha_s due to different
threshold masses obtained in the latter scenario. Finally, we present the
experimentally allowed predictions of the two models in an M_0 and M_{1/2}
parameter space.


title:
Inplication of percolation of colour strings on multiplicities,
  correlations and the transverse momentum

abstract:
  In the colour string model the impact of string percolation on
multiplicities, their long-range correlations and average transverse momentum
is studied. The multiplicities are shown to be damped by a simple factor which
follows from the percolation theory. A clear signature of the phase transition
is found to be a behaviour of the correlations for intensive observables, such
as average transverse momentum, which can be detected in the high-energy heavy
ion collisions.


title: Renormalization of chiral perturbation theory to order p^6

abstract:
  The renormalization of chiral perturbation theory is carried out to
next-to-next-to-leading order in the meson sector. We calculate the divergent
part of the generating functional of Green functions of quark currents to
O(p^6) for chiral SU(n), involving one- and two-loop diagrams. The
renormalization group equations for the renormalized low-energy constants of
O(p^6) are derived. We compare our results with previous two-loop calculations
in chiral perturbation theory.


title: Limits on $\boldmath n {\bar n}$ oscillations from nuclear stability

abstract:
  The relationship between the lower limit on the nuclear stability lifetime as
derived from the non disappearance of `stable` nuclei
($T_{d}~\gtrsim~5.4~\times~10^{31}$ yr), and the lower limit thus implied on
the oscillation time $(\tau_{n \bar n})$ of a possibly underlying
neutron-antineutron oscillation process, is clarified by studying the time
evolution of the nuclear decay within a simple model which respects unitarity.
The order-of-magnitude result $\tau_{n \bar n} \approx 2 (T_{d}/\Gamma_{\bar
n})^{1/2} > 2 \times 10^{8}$ sec, where $\Gamma_{\bar n}$ is a typical $\bar n$
nuclear annihilation width, agrees as expected with the limit on $\tau_{n \bar
n}$ established by several detailed nuclear physics calculations, but sharply
disagreeing by 15 orders of magnitude with a claim published recently in Phys.
Rev. CRAP.


title:
Phenomenological analysis of epsilon'/epsilon within an effective chiral
  lagrangian approach at O(p^6)

abstract:
  We have combined a new systematic calculation of mesonic matrix elements at
O(p^6) from an effective chiral lagrangian approach with Wilson coefficients
taken from paper by G.Buchalla et al. Rev.Mod.Phys. 68 (1996) 1125, derived in
the framework of perturbative QCD, and restricted partly by experimental data.
We derive complete expressions for K-->2pi amplitudes and compare the results
for epsilon'/epsilon with experiment.


title:
Improved Calculations of Quark Distributions in Hadrons: the case of
  pion

abstract:
  The earlier introduced method of calculation of quark distributions in
hadrons, based on QCD sum rules, is improved. The imaginary part of the virtual
photon forward scattering amplitude on some hadronic current is considered in
the case, when initial and final virtualities of the current $p^2_1$, and
$p^2_2$ are different, $p^2_1\not= p^2_2$. The operator product expansion (OPE)
in $p^2_1$, $p^2_2$ is performed. The sum rule for quark distribution is
obtained using double dispersion representation of the amplitude on one side in
terms of calculated in QCD OPE and on the other side in terms of physical
states contributions. Double Borel transformation in $p^2_1$, $p^2_2$ is
applied to the sum rule, killing background non-diagonal transition terms,
which deteriorated the accuracy in previous calculations. The case of valence
quark distribution in pion is considered, which was impossible to treat by the
previous method. OPE up to dimension 6 operators is performed and leading order
perturbative corrections are accounted. Valence $u$-quark distribution in
$\pi^+$ was found at intermediate $x$, $0.15 < x < 0.7$ and normalization point
$Q^2=2 GeV^2$. These results may be used as input for evolution equations.


title:
Initial Time Singularities in Non-Equilibrium Evolution of Condensates
  and Their Resolution in the Linearized Approximation

abstract:
  The real time non-equilibrium evolution of condensates in field theory
requires an initial value problem specifying an initial quantum state or
density matrix. Arbitrary specifications of the initial quantum state (pure or
mixed) results in initial time singularities which are not removed by the usual
renormalization counterterms. We study the initial time singularities in the
linearized equation of motion for the scalar condensate in a renormalizable
Yukawa theory in 3+1 dimensions. In this renormalizable theory the initial time
singularities are enhanced. We present a consistent method for removing these
initial time singularities by specifying initial states where the distribution
of high energy quanta is determined by the initial conditions and the
interaction effects. This is done through a Bogoliubov transformation which is
consistently obtained in a perturbative expansion.The usual renormalization
counterterms and the proper choice of the Bogoliubov coefficients lead to a
singularity free evolution equation. We establish the relationship between the
evolution equations in the linearized approximation and linear response theory.
It is found that only a very specific form of the external source for linear
response leads to a real time evolution equation which is singularity free. We
focus on the evolution of spatially inhomogeneous scalar condensates by
implementing the initial state preparation via a Bogoliubov transformation up
to one-loop. As a concrete application, the evolution equation for an
inhomogenous condensate is solved analytically and the results are carefully
analyzed. Symmetry breaking by initial quantum states is discussed.


title:
The reconstructed final state of Pb + Pb 158 AGeV reactions from spectra
  and correlation data of NA49, NA44 and WA98

abstract:
  The final state of Pb + Pb reactions at CERN SPS has been reconstructed with
the Buda-Lund hydro model, by performing a simultaneous fit to NA49, NA44 and
WA98 data on particle correlations and spectra.


title: Terrestrial Neutrino Oscillations Illustrated

abstract:
  Observations of atmospheric neutrinos offer compelling evidence that
neutrinos have mass and do oscillate. Preliminary data are compatible with
maximal $\nu_\mu$--$\nu_\tau$ mixing, but not with pure $\nu_\mu$--$\nu_e$
mixing. In a general three-family scenario with just one relevant squared-mass
difference, atmospheric neutrino oscillations involve two mixing angles. The
special cases mentioned above are not favored by convincing theoretical
arguments. As more precise data are accumulated, both at Superkamiokande and at
proposed or ongoing long-baseline experiments, it will become feasible and
desirable to measure both angles. To this end, we offer a brief portfolio of
illustrations from which the qualitative effects of the two mixing angles on
various observable quantities can be discerned.


title: What QCD Tells Us About Nature -- and Why We Should Listen

abstract:
  I discuss why QCD is our most perfect physical theory. Then I visit a few of
its current frontiers. Finally I draw some appropriate conclusions.


title: Electromagnetic Corrections to K -> pi pi I: Chiral Perturbation Theory

abstract:
  An analysis of electromagnetic corrections to the (dominant) octet K -> pi pi
hamiltonian using chiral perturbation theory is carried out. Relative shifts in
amplitudes at the several per cent level are found.


title: Duality and Chiral Restoration from Low-Mass Dileptons at the CERN-SpS

abstract:
  We review recent theoretical progress in low-mass dilepton production at
CERN-SpS energies. Various hadronic approaches to calculate the vector
correlator in hot/dense hadronic matter are discussed and confronted with each
other. Possible consequences for the nature of chiral restoration are
indicated.


title: Jet quenching in thin plasmas

abstract:
  We investigate the energy loss of quarks and gluons produced in hard
processes resulting from final state rescatterings in a finite quark-gluon
plasma. The angular distribution of the soft gluon bremsstrahlung induced by
n_s=1 rescatterings in the plasma is computed in the Gyulassy-Wang model.
Special focus is on how the interference between the initial hard radiation
amplitude, the multiple induced Gunion-Bertsch radiation amplitudes, and gluon
rescattering amplitudes modifies the classical parton cascade results.


title: Distinguishing Indirect Signatures Arising From New Physics at the NLC

abstract:
  Many sources of new physics can lead to shifts in the Standard Model
predictions for cross sections and asymmetries at the NLC below their direct
production thresholds. In this talk we discuss some of the tools that are
useful for distinguishing amongst these new physics scenarios. R-parity
violation and extensions of the Standard Model gauge structure are two typical
non-minimal realizations of supersymmetry which provide us with an important
test case to examine.


title:
Radiative neutrino transition $\nu \to \nu \gamma$ in strongly
  magnetized plasma

abstract:
  The influence of strongly magnetized electron-positron plasma on the
radiative neutrino transition $\nng$ is investigated. The probability and mean
losses of the neutrino energy and momentum are calculated taking account of the
photon dispersion and large radiative corrections near the resonance. It is
shown that the combined effect of plasma and strong magnetic field decreases
the probability and mean values of the neutrino energy and momentum loss in
comparison with these values obtained in pure magnetic field.


title: Perspectives on EPIC Physics

abstract:
  An electron-proton/ion polarized beam collider (EPIC) with high luminosity
and center-of-mass energy $\sqrt s = 25$ GeV would be a valuable facility for
fundamental studies of proton and nuclear structure and tests of quantum
chromodynamics, I review a sample of prospective EPIC topics, particularly
semi-exclusive reactions, studies of the proton fragmentation region, heavy
quark electroproduction, and a new probe of odderon/pomeron interference.


title: Compton Scattering at the NLC and Large Extra Dimensions

abstract:
  We study Compton scattering, gamma e -> gamma e, in the context of the recent
proposal for Weak Scale Quantum Gravity (WSQG) with large extra dimensions. It
is shown that, with an ultraviolet cutoff $M_S \sim 1$ TeV for the effective
gravity theory, the cross section for this process at the Next Linear Collider
(NLC) deviates from the prediction of the Standard Model significantly. Our
results suggest that, for typical proposed NLC energies and luminosities, WSQG
can be tested in the range 4 TeV$\lsim M_S \lsim$ 16 TeV, making gamma e ->
gamma e an important test channel.


title:
Multiplicity dependence of identical particle correlations in the
  quantum optical approach

abstract:
  Identical particle correlations at fixed multiplicity are consideres in the
presence of chaotic and coherent fields. The multiplicity distribution,
one-particle momentum density, and two-particle correlation function are
obtained based on the diagrammatic representation for cmulants in
semi-inclusive events. Our formulation is applied to the analysis of the
experimental data on the multiplicity dependence of correlation functions
reported by the UA1 and the OPAL Collaborations.


title:
Induced Lorentz-Violating Chern-Simons Term in QED and Anomalous
  Contributions to Effective Action Expansions

abstract:
  I present a unified formulation of anomalous contributions in quantum field
theories by calculating directly the effective action using the background
field and covariant-derivative expansion technique. I use this method to
determine uniquely the induced Chern-Simons term from the a Lorentz and CPT
violating term in fermion QED Lagrangian. The outstanding ambiguity is resolved
by properly taken into account the noncommutivity of $A$ and $\partial$. The
resulting vacuum polarization tensor acquires a non-Feynman diagram anomalous
contribution which accounts for the discrepancy between the present calculation
and the other calculations.


title:
Combined analysis of SLAC-BCDMS-NMC data at high x: \alpha_s and high
  twists

abstract:
  We perform a NLO QCD analysis of the nonsinglet part of the combined
SLAC-BCDMS-NMC data on inclusive deep inelastic cross section with the
extraction of $\alpha_s$. We show that the value of $\alpha_s$ obtained in the
analysis is sensitive to the statistical inference procedures dealing with
systematic errors on the data. The fit with the complete account of
point-to-point correlations of the data gives the value of
$\alpha_s(M_Z)=0.1183\pm0.0021(exp.)\pm0.0013(ren.scale)$ that is compatible
with the LEP measurements and the world average. Model independent x-shape of
high twist contributions to the structure functions $F_L$ and $F_2$ is
extracted. Twist-4 contribution to $F_L$ is found to be in qualitative
agreement with the predictions of infrared renormalon model. Twist-6
contribution to $F_L$ exhibit weak trend to negative values, and twist-6
contribution to $F_2$ - to positive values, although both are compatible with
zero within errors.


title: Thermal QCD sum rules in the $\rho^0$ channel revisited

abstract:
  From the hypothesis that at zero temperature the square root of the spectral
continuum threshold $s_0$ is linearly related to the QCD scale $\Lambda$ we
derive in the chiral limit and for temperatures considerably smaller than
$\Lambda$ scaling relations for the vacuum parts of the Gibbs averaged scalar
operators contributing to the thermal operator product expansion of the
$\rho^0$ current-current correlator. The scaling with $\lambda\equiv
\sqrt{s_0(T)/s_0(0)}$, $s_0$ being the $T$-dependent perturbative QCD continuum
threshold in the spectral integral, is simple for renormalization group
invariant operators, and becomes nontrivial for a set of operators which mix
and scale anomalously under a change of the renormalization point. In contrast
to previous works on thermal QCD sum rules with this approach the gluon
condensate exhibits a sizable $T$-dependence. The $\rho$ -meson mass is found
to rise slowly with temperature which coincides with the result found by means
of a PCAC and current algebra analysis of the $\rho^0$ correlator.


title:
Absorption and percolation in the production of J/psi in heavy ion
  collisions

abstract:
  We present a simple model with string absorption and percolation to describe
the J/psi suppression in heavy ion collisions. The NA50 data are fairly well
explained by the model.


title:
Exclusive channels in $\gamma\gamma$ reactions: light at the end of the
  tunnel?

abstract:
  The physics that can be learnt by studying exclusive channels in two photon
interactions is recalled. This serves as an introduction to the Exclusive
Reaction session of Photon'99.


title:
N-quantum approach to quantum field theory at finite T and $\mu$: the
  NJL model

abstract:
  We extend the N-quantum approach to quantum field theory to finite
temperature ($T$) and chemical potential ($\mu$) and apply it to the NJL model.
In this approach the Heisenberg fields are expressed using the Haag expansion
while temperature and chemical potential are introduced simultaneously through
a generalized Bogoliubov transformation. Known mean field results are recovered
using only the first term in the Haag expansion. In addition, we find that at
finite T and in the broken symmetry phase of the model the mean field
approximation can not diagonalize the Hamiltonian. Inclusion of scalar and
axial vector diquark channels in the SU(2)$_{rm f}$ $otimes$ SU(3)$_{\rm c}$
version of the model can lead to a lowering of the vacuum energy density. We
discuss how to go beyond the mean field approximation by including higher order
terms in the Haag expansion.


title: SM Kaluza-Klein Excitations and Electroweak Precision Tests

abstract:
  We consider a minimal extension to higher dimensions of the Standard Model,
having one compactified dimension, and we study its experimental tests in terms
of electroweak data. We discuss tests from high-energy data at the $Z$-pole,
and low-energy tests, notably from atomic parity violation data. This
measurement combined with neutrino scattering data strongly restricts the
allowed region of the model parameters. Furthermore this region is incompatible
at 95% CL with the restrictions from high-energy experiments. Of course a
global fit to all data is possible but the $\chi^2_{\rm min}$ for degree of
freedom is unpleasantly large.


title: Perspectives in Polarized Leptoproduction

abstract:
  We discuss specific observables that can be measured in deep inelastic
leptoproduction in the case of 1-particle inclusive measurements, namely
azimuthal asymmetries and power-suppressed (higher twist) corrections. These
quantities contain information on the intrinsic transverse momentum of partons,
with close connection to the gluon dynamics in hadrons.


title: The Forward-Backward Asymmetry in NNLO QCD

abstract:
  We have recently calculated the second-order QCD corrections to the
forward-backward asymmetry in e+e- annihilation (hep-ph/9905424). Here we
recall the results and compare them to others in the literature.


title: Symmetry Non-Restoration via Order 10^{-10} B and L Asymmetries

abstract:
  It has been observed that a large lepton asymmetry, n_{L}/s \approx 0.1, can
prevent the Higgs expectation value from going to zero at high temperature,
resulting in the non-restoration of the SU(2)XU(1) gauge symmetry and other
symmetries. This could allow for the elimination of domain walls and other
dangerous topological defects. Here we show that if the reheating temperature
after inflation, T_{R}, is sufficiently low then symmetry non-restoration will
occur with an asymmetry of the order of the observed baryon asymmetry, n_{B}/s
\approx 10^{-10}. For this to occur T_{R} \leq 1 GeV is necessary. Remarkably,
this happens to be the reheating temperature expected in Affleck-Dine
baryogenesis along a d=6 flat direction of the MSSM. As an example, we show
that this can neatly solve the Z_{3} domain wall problem of the NMSSM.


title: Lepton - Chargino Mixing and R-Parity Violating SUSY

abstract:
  We present a study of charged lepton mass matrix diagonalization in R-parity
violating SUSY. The case in which the bilinear couplings $\mu_i$ have large
values is given special attention.


title:
Phases in the gaugino sector: direct reconstruction of the basic
  parameters and impact on the neutralino pair production

abstract:
  We consider recovering analytically the (generally complex) parameters $\mu$,
$M_1$ and $M_2$ of the gaugino and Higgsino Lagrangian, from appropriate
physical input in the chargino and neutralino sectors. For given $\tan\beta$,
we obtain very simple analytic solutions for $M_2$, $| \mu|$, $Arg[\mu]$ in the
chargino sector and a twofold $| M_1 |$, $Arg[M_1]$ analytic solution in the
neutralino sector, assuming two chargino, two neutralino masses, and one of the
chargino mixing angles as physical input. The twofold ambiguity in the
neutralino parameters reconstruction may be essentially resolved by measuring
the $e^+e^- \to \chi^0_1 \chi^0_2$ production cross-section at future linear
collider energies, which we study explicitly with the phase dependences. Some
salient features and specific properties of this complex case gaugino "spectrum
inversion" are illustrated and compared with the similar inversion in the real
case. In particular, our algorithms exhibit in a direct and transparent way the
non-trivial theoretical correlation among the chargino and neutralino
parameters, and the resulting allowed domains when only a subset of the
required physical input masses and production cross-sections is known.


title: Nonstandard order parameters and the origin of CP violation

abstract:
  The consideration of chirality-preserving 2-fermion order parameters may shed
new light on the strong CP problem and the breakdown of flavor symmetries. We
describe two situations, one having the standard KM picture for weak CP
violation and another having new sources of weak CP violation.


title: Electroweak Constraints on Extended Models with Extra Dimensions

abstract:
  Electroweak measurements place significant bounds on higher-dimensional
versions of the standard model in which the gauge and Higgs fields have
Kaluza-Klein excitations. These bounds may be altered quantitatively if chiral
matter is also allowed to propagate in the higher-dimensional `bulk'. We
determine the electroweak constraints on a number of models of this type,
including scenarios in which only the leptons or only the first two generations
of matter fields propagate in the bulk. We also consider the possibility that
different factors of the electroweak gauge group may be distinguished by their
bulk/three-brane assignment, and study a minimal extra-dimensional Z' model. We
find typical bounds on the compactification scale between 1.5 and 4 TeV, and
comment on models in which these bounds might be significantly relaxed.


title: Phenomenology of V_ub from Ratios of Inclusive B Decay Rates

abstract:
  We explore the theoretical feasibility of extracting V_ub from two ratios
built from B meson inclusive partial decays,
  R_1 = Gamma(b-> u cbar s)/3Gamma(b -> c l nu), and
  R_2 = [Gamma(b -> c X) - Gamma(b -> cbar X)]/Gamma(b -> c ubar d).
  We discuss contributions to these quantities from perturbative and
nonperturbative physics, and show that they can be computed with overall
uncertainties at the level of 10%.


title: Bounds on the electromagnetic interactions of excited spin-3/2 leptons

abstract:
  We discuss possible deviations from QED produced by a virtual excited
spin-3/2 lepton in the reaction $e^+e^- \longrightarrow 2\gamma$. Data recorded
by the OPAL Collaboration at a c.m. energy $\sqrt{s} = 183 GeV$ are used to
establish bounds on the nonstandard-lepton mass and coupling strengths.


title: Dark Matter Abundance and Electroweak Baryogenesis in the CMSSM

abstract:
  The Minimal Supersymmetric Standard Model has a candidate dark matter
particle in its spectrum and may be able to generate the baryon asymmetry of
the Universe (BAU) at the electroweak phase transition. In the Constrained
MSSM, we find the area of parameter space which is allowed by accelerator and
precision tests, which produces a relic dark matter abundance in the
observationally favored window 0.1<Omega h^2<0.3, and where baryon plus lepton
number violating processes are out of equilibrium after the electroweak phase
transition.


title: Photon Structure and the Production of Jets, Hadrons, and Prompt Photons

abstract:
  We give a pedagogical introduction to hard photoproduction processes at HERA,
including the production of jets, hadrons, and prompt photons. Recent
theoretical developments in the three areas are reviewed.


title: Shadowing Effects on Particle and Transverse Energy Production

abstract:
  The effect of shadowing on the early state of ultrarelativistic heavy ion
collisions and transverse energy production is discussed. Results are presented
for RHIC Au+Au collisions at $\sqrt{s_{NN}} = 200$ GeV and LHC Pb+Pb collisions
at $\sqrt{s_{NN}} = 5.5$ TeV.


title: Pair Production of the Lightest Chargino via Gluon-Gluon Collisions

abstract:
  The production of the lightest chargino pair from gluon-gluon fusion is
studied in the minimal supersymmetric model(MSSM) at proton-proton colliders.
We find that with the chosen parameters, the production rate of the subprocess
can be over 2.7 femto barn when the chargino is higgsino-like, and the
corresponding total cross section in proton-proton collider can reach 56 femto
barn at the LHC in the CP-conserving MSSM. It shows that this loop mediated
subprocess can be competitive with the standard Drell-Yan subprocess in
proton-proton colliders, especially at the LHC. Furthermore, our calculation
shows it would be possible to extract information about some CP-violating phase
parameters, if we collected enough chargino pair events.


title:
The Nonlinear Permittivity Including Non-Abelian Self-interaction of
  Plasmons in Quark-Gluon Plasma

abstract:
  By decomposing the distribution functions and color field to regular and
fluctuation parts, the solution of the semi-classical kinetic equations of
quark-gluon plasma is analyzed. Through expanding the kinetic equations of the
fluctuation parts to third order, the nonlinear permittivity including the
self-interaction of gauge field is obtained and a rough numerical estimate is
given out for the important $\vk =0$ modes of the pure gluon plasma.


title: Direct CP Violation in Charmed Hadron Decays via $\rho-\omega$ Mixing

abstract:
  We study the possibility of obtaining large direct CP violation in the
charmed hadron decays $D^+ \to \rho^+ \rho^0 (\omega) \to \rho^+ \pi^+\pi^-$,
$D^+ \to \pi^+ \rho^0 (\omega) \to \pi^+ \pi^+\pi^-$, $D^0 \to \phi \rho^0
(\omega) \to\phi \pi^+\pi^-$, $D^0 \to\eta \rho^0 (\omega) \to\eta \pi^+\pi^-$,
$D^0 \to \eta' \rho^0 (\omega) \to\eta' \pi^+\pi^-$, $D^0 \to \pi^0 \rho^0
(\omega) \to \pi^0 \pi^+\pi^-$, and $\Lambda_c \ra p \rho^0 (\omega) \to p
\pi^+\pi^-$ via $\rho-\omega$ mixing. The analysis is carried out in the
factorization approach. The CP violation parameter depends on the effective
parameter, $N_{c}$, which is relevant to hadronization dynamics of each decay
channel and should be determined by experiments. It is found that for fixed
$N_{c}$ the CP violation parameter reaches its maximum value when the invariant
mass of the $\pi^+\pi^-$ pair is in the vicinity of the $\omega$ resonance. For
$D^0 \to \pi^0 \rho^0 (\omega) \to \pi^0 \pi^+\pi^-$ and $\Lambda_c \to p
\rho^0 (\omega) \to p \pi^+\pi^-$ the maximum CP violating asymmetry is bigger
than 1% when $1.98\leq N_c \leq 1.99$ and $1.95\leq N_c \leq 2.02$,
respectively. We also estimate the decay branching ratios for $D^0 \to \pi^0
\rho^0$ and $\Lambda_c \to p \rho^0$ for these values of $N_c$, which should be
tested by future experimental data.


title:
Diffractive light quark jet and gluon jet production at hadron colliders
  in the two-gluon exchange model

abstract:
  Massless diquark jet and gluon jet productions at large transverse momentum
in the coherent diffractive processes at hadron colliders are studied in the
two-gluon exchange parametrization of the Pomeron model. We use the helicity
amplitude method to calculate the cross section formulas. We find that for the
light quark jet and gluon jet production the diffractive process is related to
t he differential off-diagonal gluon distribution function in the proton. We
estimate the production rate for these processes at the Fermilab Tevatron by
approximating the off-diagonal gluon distribution function by the usual
diagonal gluon distribution in the proton. We also use the helicity amplitude
method to calculate the diffractive charm jet production at hadron colliders,
by which we reproduce the leading logarithmic approximation result of this
process we previously calculated.


title: Neutrinos from Stellar Collapse: Effects of flavour mixing

abstract:
  We study the effect of non-vanishing masses and mixings among neutrino
flavours on the detection of neutrinos from stellar collapse by a water
Cerenkov detector. We consider a realistic framework in which there are three
neutrino flavours whose mass squared differences and mixings are constrained by
the present understanding of solar and atmospheric neutrinos. We also include
the effects of high dense matter within the supernova core. We find that the
number of events due to the dominant process involving electron-antineutrinos
may change dramatically for some allowed mixing parameters. Furthermore,
contributions from charged-current scattering off oxygen atoms in the detector
can be considerably enhanced due to flavour mixing; such events have a distinct
experimental signature since they are backward-peaked. Hence, mixing has a
non-trivial effect on the signature of neutrinos (and antineutrinos) from
stellar collapse.


title: Gluons and the eta' nucleon coupling constant

abstract:
  We derive the effective chiral Lagrangian for low energy eta--nucleon and
eta'--nucleon interactions and show that gluonic degrees of freedom, via the
axial anomaly, induce a contact term in the pp -> pp eta and pp -> pp eta'
reactions. We then discuss the consequences for the extraction of g_{eta'NN}
from experimental data.


title: Interference Fragmentation Functions in Deep Inelastic Scattering

abstract:
  We give a general overview of the role and interpretation of fragmentation
functions in hard processes. Transverse momentum dependence gives rise to
time-reversal odd fragmentation functions contributing at leading order. Final
state interactions are necessary to have non-zero time reversal odd functions.
We present a model calculation for the special case of interference
fragmentation functions in two-hadron inclusive lepton hadron scattering.


title:
Branching ratio and CP violation in semi-inclusive flavor-changing top
  decays

abstract:
  The top quark decay process $\tcups$ is studied in the Standard Model and the
Minimal Supersymmetric Standard Model with conserved and violated $R-$parity.
In dealing with the heavy quarkonium, $\ups$, production, we take both
color-singlet and -octet mechanisms into consideration. With numerical analysis
it is found that within the Standard Model the decay rate of the concerned
process is beyond the border of reachable level of the next round of
experiment, though it is much larger than that of the rare top decays, while
extra new contributions from beyond the Standard Model could enhance the decay
rate by several orders. It is also noticed that a precise measurement of the
charged Higgs mass without $\tan\beta$ dependence is possible via this process.


title: Probing the $WW\gamma$ vertex at hadron colliders

abstract:
  We present a new, model independent method for extracting bounds for the
anomalous $\gamma WW$ couplings from hadron collider experiments. At the
partonic level we introduce a set of three observables which are constructed
from the unpolarized differential cross-section for the process $d\bar{u}\to
W^{-}\gamma$ by appropriate convolution with a set of simple polynomials
depending only on the center-of-mass angle. One of these observables allows for
the direct determination of the anomalous coupling usually denoted by
$\Delta\kappa$, without any simplifying assumptions, and without relying on the
presence of a radiation zero. The other two observables impose two sum rules on
the remaining three anomalous couplings. The inclusion of the structure
functions is discussed in detail for both $p\bar{p}$ and $pp$ colliders. We
show that, whilst for $p\bar{p}$ experiments this can be accomplished
straightforwardly, in the $pp$ case one has to resort to somewhat more
elaborate techniques, such as the binning of events according to their
longitudinal momenta.


title: Large Higgs Boson Exchange Contribution in Three-Body Neutralino Decays

abstract:
  We show that the Higgs boson exchange contribution can be large in three-body
decays of neutralinos even in the case of small tan(beta). This enlarges the
branching ratios for the decays neutralino_2 -> neutralino_1 b \bar{b} and
neutralino_2 -> neutralino_1 tau- tau+. This is the case in the region of the
parameter space where the two lightest neutralinos are gaugino-like, the
sfermions are heavier than 300 GeV, and m_A0 = 200 GeV or smaller.


title: QCD-based description of one-particle inclusive B decays

abstract:
  We discuss one-particle inclusive B decays in the limit of heavy b and c
quarks. Using the large-N_C limit we factorize the non-leptonic matrix
elements, and we employ a short distance expansion. Modeling the remaining
nonperturbative matrix elements we obtain predictions for various decay
channels and compare them with existing data.


title:
Effective Hamiltonian Approach to Hyperon Beta Decay with Final-State
  Baryon Polarization

abstract:
  Using an effective Hamiltonian approach, we obtain expressions for hyperon
beta decay final-state baryon polarization. Terms through second order in the
energy release are retained. The resulting approximate expressions are much
simpler and more compact than the exact expressions, and they agree closely
with them.


title:
Global Analysis of Bhabha Scattering at LEP2 and Limits on Low Scale
  Gravity Models

abstract:
  A global analysis of the data on Bhabha scattering from the four LEP
experiments ALEPH, DELPHI, L3 and OPAL is performed to search for effects of
virtual graviton exchange in models with low scale gravity. No statistically
significant deviations from the Standard Model expectations are observed and
lower limits on the scale of models with large extra dimensions of $\Lambda_T =
1.077 TeV$ for $\lambda = -1$ and $\Lambda_T = 1.412 TeV$ for $\lambda = +1$ at
95% confidence level are derived.


title: Sphaleron Transition Rate in Presence of Dynamical Fermions

abstract:
  We investigate the effect of dynamical fermions on the sphaleron transition
rate at finite temperature for the Abelian Higgs model in one spatial
dimension. The fermion degrees of freedom are included through bosonization.
Using a numerical simulation, we find that massless fermions do not change the
rate within the measurement accuracy. Surprisingly, the exponential dependence
of the sphaleron energy on the Yukawa coupling is not borne out by the
transition rate, which shows a very weak dependence on the fermion mass.


title: Remarks on the neutrino oscillation formula

abstract:
  We show that the neutrino oscillation formula recently derived in the quantum
field theory framework holds true despite the arbitrariness in the mass
parameter for the flavor fields. This formula is exact and exhibits new
features with respect to the usual Pontecorvo formula, which is however valid
in the relativistic limit.


title:
Neutrino magnetic moments, flavor mixing, and the SuperKamiokande solar
  data

abstract:
  We find that magnetic neutrino-electron scattering is unaffected by
oscillations for vacuum mixing of Dirac neutrinos with only diagonal moments
and for Majorana neutrinos with two flavors. For MSW mixing, these cases again
obtain, though the effective moments can depend on the neutrino energy. Thus,
e.g., the magnetic moments measured with $\bar{\nu}_e$ from a reactor and
$\nu_e$ from the Sun could be different. With minimal assumptions, we find a
new limit on $\mu_{\nu}$ using the 825-days SuperKamiokande solar neutrino
data: $|\mu_{\nu}| \le 1.5\times 10^{-10} \mu_B$ at 90% CL, comparable to the
existing reactor limit.


title:
Neutrino-photon scattering and its crossed processes in a background
  magnetic field

abstract:
  We study the neutrino-photon processes such as $\gamma\gamma\to \nu\bar{\nu}$
and $\nu\gamma\to \nu\gamma$ in a background magnetic field smaller than the
critical magnetic field $B_c\equiv m_e^2/e$. Using Schwinger's proper-time
method, we extract leading magnetic-field contributions to the above processes.
Our result is valid throughout the kinematic regime where both neutrino and
photon energies are significantly smaller than $m_W$. We briefly discuss the
astrophysical implications of our result.


title:
Analytical Results for Dimensionally Regularized Massless On-shell
  Double Boxes with Arbitrary Indices and Numerators

abstract:
  We present an algorithm for the analytical evaluation of dimensionally
regularized massless on-shell double box Feynman diagrams with arbitrary
polynomials in numerators and general integer powers of propagators. Recurrence
relations following from integration by parts are solved explicitly and any
given double box diagram is expressed as a linear combination of two master
double boxes and a family of simpler diagrams. The first master double box
corresponds to all powers of the propagators equal to one and no numerators,
and the second master double box differs from the first one by the second power
of the middle propagator. By use of differential relations, the second master
double box is expressed through the first one up to a similar linear
combination of simpler double boxes so that the analytical evaluation of the
first master double box provides explicit analytical results, in terms of
polylogarithms $\Li{a}{-t/s}$, up to $a=4$, and generalized polylogarithms
$S_{a,b}(-t/s)$, with $a=1,2$ and $b=2$, dependent on the Mandelstam variables
$s$ and $t$, for an arbitrary diagram under consideration.


title:
Angular Distribution and CP Asymmetries in the Decays B->K^-pi^+e^-e^+
  and B->pi^-pi^+e^-e^+

abstract:
  The short-distance Hamiltonian describing b->s(d)e^-e^+ in the standard model
is used to obtain the decay spectrum of \bar{B}->K^-pi^+e^-e^+ and
\bar{B}->pi^-pi^+e^-e^+, assuming the Kpi and pipi systems to be the decay
products of K^* and rho respectively. Specific features calculated are (i)
angular distribution of K^- (or pi^-) in the K^-pi^+ (or pi^-pi^+)
centre-of-mass (c.m.) frame; (ii) angular distribution of e^- in the e^-e^+
c.m. frame; and (iii) the correlation between the meson and lepton planes. We
also derive CP-violating observables obtained by combining the above decays
with the conjugate processes B->K^+pi^-e^-e^+ and B->pi^-pi^+e^-e^+.


title:
NNLO Calculation of DIS; Precision Determination of the Strong Coupling
  Constant, Extraction of the Gluon Density, and Comments on "Hidden" Gluinos

abstract:
  Calculations of deep inelastic processes (DIS) to next-to-next to leading
order are discussed. Fitting $ep$ experiment in the range $2.5\leq Q^2\leq 230
GeV^2$, we find the coupling $\alpha_s(M_Z^2)=0.1163\pm0.0023$. We also get the
gluon density $xG(x,Q^2\simeq 10 GeV^2)=0.51 x^{-0.44}(1-x)^{8.1}$, and
negative evidence for the existence of light gluinos


title: A Review of pQCD Calculations of Electromagnetic Form Factors of Hadrons

abstract:
  We review the current status of perturbative QCD calculation of hadronic
electromagnetic form factors.


title: The role of the top mass in b-production at future lepton colliders

abstract:
  We compute the one loop contribution coming from vertex and box diagrams,
where virtual top quarks are exchanged, to the asymptotic energy behaviour of
$b\bar b$ pair production at future lepton colliders. We find that the effect
of the top mass is an extra linear logarithmic term of Sudakov type that is not
present in the case of (u,d,s,c) production. This appears to be particularly
relevant in the case of the $b\bar{b}$ cross section.


title: Neutrino Anomalies in an Extended Zee Model

abstract:
  We discuss an extended $SU(2)\times U(1)$ model which naturally leads to mass
scales and mixing angles relevant for understanding both the solar and
atmospheric neutrino anomalies. No right-handed neutrinos are introduced in the
model.The model uses a softly broken $L_e-L_{\mu}-L_{\tau}$ symmetry. Neutrino
masses arise only at the loop level. The one-loop neutrino masses which arise
as in the Zee model solve the atmospheric neutrino anomaly while breaking of
$L_e-L_{\mu}-L_{\tau}$ generates at two-loop order a mass splitting needed for
the vacuum solution of the solar neutrino problem. A somewhat different model
is possible which accommodates the large-angle MSW resolution of the solar
neutrino problem.


title: The Resummed Rate for B -> X_s gamma

abstract:
  In this paper we investigate the effect of the resummation of threshold logs
on the rate for B -> X_s gamma. We calculate the differential rate
dGamma/dE_gamma including the infinite set of terms of the form alpha_s^n
log^{n+1}(1-x) and alpha_s^n log^n(1-x) in the Sudakov exponent. The
resummation is potentially important since these logs turn into
log(2E_{cut}/m_b), when the rate is integrated from the lower cut
x=2E_{cut}/m_b to 1. The resummed rate is then convolved with models for the
structure function to study whether or not the logs will be enhanced due to the
fermi motion of the heavy quark. A detailed discussion of the accuracy of the
calculation with and without the inclusion of the non-perturbative effects
dictated by the B meson structure function is given. We also investigate the
first moment with respect to (1-x), which can be used to measure \bar\Lambda
and lambda_1. It is shown that there are some two loop corrections which are
just as large as the alpha_s^2 beta_0 term, which are usually expected to
dominate. We conclude that, for the present energy cut, the threshold logs do
not form a dominant sub-series and therefore their resummation is unnecessary.
Thus, the prospects for predicting the rate for B -> X_s gamma accurately,
given the present energy cut, are promising.


title: Soft and hard pomerons

abstract:
  Regge theory provides an excellent description of small-$x$
structure-function data from $Q^2=0$ up to the highest available values. The
large-$Q^2$ data should also be described by perturbative QCD: the two
descriptions must agree in the region where they overlap. However, at present
there is a serious lack in our understanding of how to apply perturbative QCD
at small $x$. The usual lowest-order or next-to-lowest order expansion is not
valid, at least not until $Q^2$ becomes much larger than is usually assumed; a
resummation is necessary, but as yet we do not know how to do this resummation.


title: Renormalization and Symmetry Conditions in Supersymmetric QED

abstract:
  For supersymmetric gauge theories a consistent regularization scheme that
preserves supersymmetry and gauge invariance is not known. In this article we
tackle this problem for supersymmetric QED within the framework of algebraic
renormalization. For practical calculations, a non-invariant regularization
scheme may be used together with counterterms from all power-counting
renormalizable interactions. From the Slavnov--Taylor identity, expressing
gauge invariance, supersymmetry and translational invariance, simple symmetry
conditions are derived that are important in a twofold respect: they establish
exact relations between physical quantities that are valid to all orders, and
they provide a powerful tool for the practical determination of the
counterterms. We perform concrete one-loop calculations in dimensional
regularization, where supersymmetry is spoiled at the regularized level, and
show how the counterterms necessary to restore supersymmetry can be read off
easily. In addition, a specific example is given how the supersymmetry
transformations in one-loop order are modified by non-local terms.


title: A Global Study of Photon-Induced Jet Production

abstract:
  We present results of a global tuning of general purpose Monte Carlo models
to published measurements of photon-proton -> jets at HERA and photon-photon ->
jets at LEP and TRISTAN. The principle free parameters in the tuning are the
simulation of the underlying event and the choice of photon structure. Several
combinations of models are ruled out by the data. Some consequences of the
tuned models at a future linear collider are discussed.


title:
Polarization Asymmetries in $\gamma e$ Collisions and Triple Gauge Boson
  Couplings Revisited

abstract:
  The capability of the NLC run in the $\gamma e$ collision mode to probe the
CP-conserving $\gamma WW$ and $\gamma ZZ$ anomalous couplings through the use
of the polarization asymmetry is reviewed. When combined with other
measurements, very strong constraints on both varieties of anomalous couplings
can be obtained. We show that these bounds are complementary to those that can
be extracted from data taken at the LHC.


title: Precision GMSB at a Linear Collider

abstract:
  We simulate precision measurements of gauge-mediated supersymmetry breaking
(GMSB) parameters at a 500 GeV e+e- linear collider in the scenario where a
neutralino is the next-to-lightest supersymmetric particle. Information on the
supersymmetry breaking and the messenger sectors of the theory is extracted
from the measured sparticle mass spectrum and neutralino lifetime.


title: Towards a grand unified picture for neutrino and quark mixings

abstract:
  The comparison of the CKM mixing angles with the leptonic mixings implied by
the recent atmospheric and solar neutrino data exhibits an interesting
complementarity. This pattern can be understood in the context of the SU(5)
grand unification, assuming that the fermion mass matrices have Fritzsch-like
structures but are not necessarily symmetric. (The present contribution is
based on the paper in ref. \cite{az}.)


title: Right handed neutrino production in dense and hot plasmas

abstract:
  For Dirac neutrinos with magnetic moment, we compute the production rate for
right-handed neutrinos in a hot and dense QED plasma containing an initial
population of left-handed neutrinos thermally distributed. The most important
mechanisms for $\nu_L$ depolarization, or production of right-handed neutrinos,
are the $\nu_L \to \nu_R$ chirality flip and the plasmon decay to $\bar{\nu}_L
+ \nu_R$. The rates for these processes are computed in terms of a resummed
photon propagator which consistently incorporates the background effects to
leading order. Applying the results to the cases of supernovae core collapse
and the primordial nucleosynthesis in the early universe, we obtain upper
limits on the neutrino magnetic moment.


title: Resonance spin flavour precession and solar neutrinos

abstract:
  We examine the prospects for the resonance spin flavour precession as a
solution to the solar neutrino problem. We study seven different realistic
solar magnetic field profiles and, by numerically integrating the evolution
equations, perform a fit of the event rates for the three types of solar
neutrino experiments (Ga, Cl and SuperKamiokande) and a fit of the energy
spectrum of the recoil electrons in SuperKamiokande. A $\chi^2$ analysis shows
that the quality of the rate fits is excellent for two of the field profiles
and good for all others with $\chi^2 /d.o.f.$ always well below unity.
Regarding the fits for the energy spectrum, their quality is better than that
for the small mixing angle MSW solution of the solar neutrino problem, at the
same level as that for the large mixing angle MSW solution but worse than that
for the vacuum oscillations one. The experimental data on the spectrum are
however largely uncertain especially in the high energy sector, so that it is
too early yet to draw any clear conclusions on the likeliest type of particle
physics solution to the solar neutrino problem.


title: Stability of Neutrino Mass Degeneracy

abstract:
  Two neutrinos of Majorana masses $m_{1,2}$ with mixing angle $\theta$ are
unstable against radiative corrections in the limit $m_1 = m_2$, but are stable
for $m_1 = -m_2$ (i.e. opposite CP eigenstates) with $\theta = 45^\circ$ which
corresponds to an additional symmetry.


title:
Tests of Low Scale Quantum Gravity in $e^-e^-$ and $\gamma \gamma$
  Collisions

abstract:
  Arkani-Hamed, Dimopoulos and Dvali have recently proposed that gravity may
become strong at energies near 1 TeV due to the existence of large extra
dimensions thus `removing' the hierarchy problem. In this talk we examine the
exchange of towers of Kaluza-Klein gravitons and their influence on Moller
scattering as well as the production of pairs of massive gauge bosons in
$\gamma \gamma$ collisions. These tower exchanges lead to a set of new
dimension-8 operators that can significant alter the Standard Model
expectations for these processes. In the case of $\gamma \gamma$ collisions,
the role of polarization for both the initial state photons and the final state
gauge bosons in improving sensitivity to graviton exchange is emphasized.


title: Extended Open Inflation

abstract:
  We present a new type of one-field models for open inflation utilizing a
nonminimally coupled scalar field with polynomial potentials in which the
Coleman-de Luccia instanton does exist and slow-roll inflation after the bubble
nucleation is realized.


title:
Estimate of Wolfenstein's Parameters rho and eta Based on a Geometry
  Viewpoint to the Weak CP Phase

abstract:
  Based on a geometric postulation on the weak CP phase in
Cabibbo-Kobayashi-Maskawa (CKM) matrix, a positive rho is asserted. Besides,
0.18<eta<0.54 and 0.048<rho<0.140 are permitted by the present data. The
corresponding geometric constraint on Wolfenstein's parameters is also worked
out. We find that, according to the geometry viewpoint, eta and rho satisfy an
approximate linear relation. These results can be put to the more precisely
tests in near future.


title: Exact gauge invariant mass dependence of \alpha_s through two loops

abstract:
  A physically defined QCD coupling parameter naturally incorporates massive
quark flavor thresholds in a gauge invariant, renormalization scale independent
and analytical way. In this paper we summarize recent results for the
finite-mass fermionic corrections to the heavy quark potential through two
loops leading to the numerical solution of the physical and mass dependent
Gell-Mann Low function. The decoupling-, massless- and Abelian-limits are
reproduced and an analytical fitting function is obtained in the V-scheme. Thus
the gauge invariant mass dependence of $\alpha_V$ is now known through two
loops. Possible applications in lattice analyses, heavy quark physics and
effective charges are briefly discussed.


title: B Decays as a Probe of Spontaneous CP-Violation in SUSY Models

abstract:
  We consider phenomenological implications of susy models with spontaneously
broken CP-symmetry. In particular, we analyze CP-asymmetries in B decays and
find that the predictions of these models are vastly different from those of
the SM. These features are common to NMSSM-like models with an arbitrary number
of sterile superfields and the MSSM with broken R-parity.


title: Implementation of the Non-Linear Gauge into GRACE

abstract:
  A general non-linear gauge condition is implemented into GRACE, an automated
system for the calculation of physical processes in high-energy physics. This
new gauge-fixing is used as a very efficient means to check the results of
large scale evaluation in the standard model computed automatically. We report
on some systematic test-runs which have been performed for one-loop two-to-two
processes to show the validity of the gauge check.


title: A gluon condensate term in a heavy quark mass

abstract:
  We investigate a connection between a renormalon ambiguity of heavy quark
mass and the gluon condensate contribution into the quark dispersion law
related with a virtuality defining a displacement of the heavy quark from the
perturbative mass-shell, which happens inside a hadron.


title: A 3-Dimensional Calculation of Atmospheric Neutrino Flux

abstract:
  An extensive 3-dimensional Monte Carlo calculation of the atmospheric
neutrino flux is in progress with the FLUKA Monte Carlo code. The results are
compared to those obtained under the 1-dimensional approximation, where
secondary particles and decay products are assumed to be collinear to the
primary cosmic ray, as usually done in most of the already existing flux
calculations. It is shown that the collinear approximation gives rise to a
wrong angular distribution of neutrinos, essentially in the Sub-GeV region.
However, the angular smearing introduced by the experimental inability of
detecting recoils in neutrino interactions with nuclei is large enough to wash
out, in practice, most of the differences between 3-dimensional and
1-dimensional flux calculations. Therefore, the use of the collinear
approximation should have not introduced a significant bias in the
determination of the flavor oscillation parameters in current experiments.


title: A collinear model for small-x physics

abstract:
  We propose a simple model for studying small-x physics in which we take only
the collinearly enhanced part of leading and subleading kernels, for all
possible transverse momentum orderings. The small-x equation reduces to a
second order differential equation in t=log k^2/Lambda^2 space, whose
perturbative and strong-coupling features are investigated both analytically
and numerically. For two-scale processes, we clarify the transition mechanism
between the perturbative, non Regge regime and the strong-coupling Pomeron
behavior.