title:
QCD Corrections and Non-standard Three Vector Boson Couplings in
  $W^+W^-$ Production at Hadron Colliders

abstract:
  The process $p\,p\hskip-7pt\hbox{$^{^{(\!-\!)}}$} \rightarrow W^{+} W^{-} + X
\rightarrow \ell^+_1 \nu_1 \ell^-_2 \bar \nu_2 + X$ is calculated to ${\cal
O}(\alpha_s)$ for general $C$ and $P$ conserving $WWV$ couplings ($V=\gamma,\,
Z$). The prospects for probing the $WWV$ couplings in this reaction are
explored. The impact of ${\cal O}(\alpha_s)$ QCD corrections and various
background processes on the observability of non-standard $WWV$ couplings in
$W^+ W^-$ production at the Tevatron and the Large Hadron Collider (LHC) is
discussed in detail. Sensitivity limits for anomalous $WWV$ couplings are
derived at next-to-leading order for the Tevatron and LHC center of mass
energies, and are compared to the bounds which can be achieved in other
processes. Unless a jet veto or a cut on the total transverse momentum of the
hadrons in the event is imposed, the ${\cal O}(\alpha_s)$ QCD corrections and
the background from top quark production decrease the sensitivity of
$p\,p\hskip-7pt\hbox{$^{^{(\!-\!)}}$} \rightarrow W^{+} W^{-} + X \rightarrow
\ell^+_1 \nu_1 \ell^-_2 \bar \nu_2 + X$ to anomalous $WWV$ couplings by a
factor two to five.


title: Quark-Hadron Duality and $\gamma^* p \to \Delta$ Form Factors

abstract:
  We use local quark-hadron duality to estimate the purely nonperturbative soft
contribution to the $\gamma^*p\to \Delta$ form factors. Our results are in
agreement with existing experimental data. We predict that the ratio
$G_E^*(Q^2)/G_M^*(Q^2)$ is small for all accessible $Q^2$, in contrast to the
pQCD expectations that $G_E^*(Q^2)\to -G_M^*(Q^2)$.


title:
Intermediate mass Higgs bosons of the Minimal Supersymmetric Standard
  Model at the proposed CERN LEP$\otimes$LHC $ep$ collider

abstract:
  The production of the \mssm\ Higgs bosons $H^0,h^0,A^0$ and $H^\pm$, in the
intermediate mass range of the $A^0$, at two different values of $\tan\beta$,
is studied at the possible CERN LEP$\otimes$LHC $ep$ collider, through $\gamma
p$ interactions, by photons generated via Compton back--scattering of laser
light. Signatures in which $H^0,h^0,A^0\ar b\bar b$ and $H^\pm\ar \tau\nu_\tau$
are considered. Flavour identification on $b$--jets is assumed. Backgrounds to
Higgs signals are computed. Explicit formulae for the helicity amplitudes of
the Higgs processes are given.


title:
A Parton Shower Model for Hadronic Two-Photon Process in e^+e^-
  Scatterings

abstract:
  A new model of QCD parton shower is proposed which is dedicated to two-photon
process in $e^+ e^-$ scattering. When hadron jets are produced, the photon may
resolve into quark-antiquark pairs so that the structure functions of the
photon should be introduced. Based on the Altarelli-Parisi equation for these
functions, an algorithm is formulated that allows us to construct a model for
parton showers for the photon. Our model consists of two parts, one of which
describes the deep inelastic scattering of the photon and the other one the
scattering of two quasi-real photons. Using the model some results are
presented on parton distributions and jet production.


title: Ratios of $B$ and $D$ Meson Decay Constants in Relativistic Quark Model

abstract:
  We calculate the ratios of $B$ and $D$ meson decay constants by applying the
variational method to the relativistic hamiltonian of the heavy meson. We adopt
the Gaussian and hydrogen-type trial wave functions, and use six different
potentials of the potential model. We obtain reliable results for the ratios,
which are similar for different trial wave functions and different potentials.
The obtained ratios show the deviation from the nonrelativistic scaling law,
and they are in a pretty good agreement with the results of the Lattice
calculations.


title:
Bloch-Nordsieck Thermometers: One-loop Exponentiation in Finite
  Temperature QED

abstract:
  We study the scattering of hard external particles in a heat bath in a
real-time formalism for finite temperature QED. We investigate the distribution
of the 4-momentum difference of initial and final hard particles in a fully
covariant manner when the scale of the process, $Q$, is much larger than the
temperature, $T$. Our computations are valid for all $T$ subject to this
constraint. We exponentiate the leading infra-red term at one-loop order
through a resummation of soft (thermal) photon emissions and absorptions. For
$T>0$, we find that tensor structures arise which are not present at $T=0$.
These carry thermal signatures. As a result, external particles can serve as
thermometers introduced into the heat bath. We investigate the phase space
origin of $\log(Q/m)$ and $\log(Q/T)$ terms.


title: Covariant quark model of form factors in the heavy mass limit

abstract:
  We show that quark models of current matrix-elements based on the
Bakamjian-Thomas construction of relativistic states with a fixed number of
particles, plus the additivity assumption, are covariant in the heavy-quark
limit and satisfy the full set of heavy-quark symmetry relations discovered by
Isgur and Wise. We find the lower bound of $\rho^2$ in such models to be $3/4$
for ground state mesons, independently of any parameter. Another welcome
property of these models is that in the infinite momentum limit the wave
functions vanish outside the domain $0\le x \le 1$.


title: The Return of The Prodigal Goldstone Boson

abstract:
  We propose that the mass of the $\eta^\prime$ meson is a particularly
sensitive probe of the properties of finite energy density hadronic matter and
quark gluon plasma. We argue that the mass of the $\eta^\prime$ excitation in
hot and dense matter should be small, and therefore that the $\eta^\prime$
production cross section should be much increased relative to that for pp
collisions. This may have observable consequences in dilepton and diphoton
experiments.


title: Non-Standard Neutrino Interactions and Neutrino Oscillation Experiments

abstract:
  In analyzing neutrino oscillation experiments it is often assumed that while
new physics contributes to neutrino masses, neutrino interactions are given by
the Standard Model. We develop a formalism to study new physics effects in
neutrino interactions using oscillation experiments. We argue that the notion
of branching ratio is not appropriate in this case. We show that a neutrino
appearance experiment with sensitivity to oscillation probability
$P_{ij}^{exp}$ can detect new physics in neutrino interactions if its strength
$G_N$ satisfies $(G_N/G_F)^2 \sim P_{ij}^{exp}$. Using our formalism we show
how current experiments on neutrino oscillation give bounds on the new
interactions in various new physics scenarios.


title: Pseudoscalar Conversion and X-rays from the Sun

abstract:
  We investigate the detection of a pseudoscalar $\phi$ that couples
electromagnetically via an interaction ${1\over4}g \phi F {\tilde F}$. In
particular, we focus on the conversion of pseudoscalars produced in the sun's
interior in the presence of the sun's external magnetic dipole field and
sunspot-related magnetic fields. We find that the sunspot approach is superior.
Measurements by the SXT on the Yohkoh satellite can measure the coupling
constant down to $g=0.5$--$1 \times 10^{-10}\,\rm GeV^{-1}$, provided the
pseudoscalar mass $m < 7{\times} 10^{-6}\,$eV, which makes it competitive with
other astrophysical approaches.


title:
Diffractive Contribution to the Elasticity and the Nucleonic Flux in the
  Atmosphere

abstract:
  We calculate the average elasticity considering non-diffractive and single
diffractive interactions and perform an analysis of the cosmic-ray flux by
means of an analytical solution for the nucleonic diffusion equation. We show
that the diffractive contribution is important for the adequate description of
the nucleonic and hadronic fluxes in the atmosphere.


title: Cheshire Cat Scenario in a 3+1 dimensional Hybrid Chiral Bag

abstract:
  The total energy in the two-phase chiral bag model is studied, including the
contribution due to the bag (Casimir energy plus energy of the valence quarks),
as well as the one coming from the Skyrmion in the external sector. A
consistent determination of the parameters of the model and the renormalization
constants in the energy is performed. The total energy shows an approximate
independence with the bag radius (separation limit between the phases), in
agreement with the Cheshire Cat Principle.


title: Neutrino Masses in an Extended Gauge Model with E_6 Particle Content

abstract:
  Naturally light singlet neutrinos which mix with the usual doublet neutrinos
are possible if the supersymmetric standard gauge model is extended to include
a specific additional U(1) factor derivable from E_6 decomposition. The
low-energy particle content of the model is limited to the fundamental 27
representations of E_6.


title: Conservation of Statistics and Generalized Grassmann Numbers

abstract:
  Conservation of statistics requires that fermions be coupled to Grassmann
external sources. Correspondingly, conservation of statistics requires that
parabosons, parafermions and quons be coupled to external sources that are the
appropriate generalizations of Grassmann numbers.


title: Electroweak Strings and Fermions

abstract:
  Z-strings in the Weinberg-Salam model including fermions are unstable for all
values of the parameters. The cause of this instability is the fermion vacuum
energy in the Z-string background. Z-strings with non-zero fermion densities,
however, may still be stable.


title: Treating Top Differently from Charm and Up

abstract:
  It now appears phenomenologically that the third family may be essentially
different from the first two. Particularly the high value of the top quark mass
suggests a special role. In the standard model all three families are treated
similarly [becoming exactly the same at asymptotically high energies] so I need
to extend the model to accommodate the goal of a really different third family.
In this article I describe not one but two such viable extensions, quite
different one from another. The first is the 331 model which predicts
dileptonic gauge bosons. In the second, using as a flavor symmetry a finite
nonabelian dicyclic $Q_{2N}$ group, I show how to derive quark mass matrices
with two arrangements of symmetric texture zeros which are phenomenologically
viable. Three other such acceptable textures in the recent literature are
unattainable in this approach and hence disfavored. I assume massive
vector-like fermions and Higgs singlets transforming as judiciously-chosen
$Q_{2N}$ doublets and use the tree-level mass generation mechanism of Froggatt
and Nielsen.


title: Just So? Vacuum Oscillations and MSW: An Update

abstract:
  We find that vacuum oscillations (VO), large-mixing-angle and
small-mixing-angle MSW solutions to the solar neutrino problem (SNP) give all
very good fits to the most recent results. Measurements of the $^7$Be flux can,
in some cases, discriminate between different solutions to the SNP; in
particular, VO allow $^7$Be fluxes almost as large as the one predicted by the
SSM. We find that no evidence for seasonal variations can be extracted from
present data, but that the large statistics of SuperKamiokande should make
possible to study a significant portion of the presently allowed parameter
space by just looking for seasonal variations. We also discuss the Borexino
potential for detecting seasonal variations, which looks really impressive.


title: Phenomenology of Quarkonium Production in Hadronic Collisions

abstract:
  We review recent progress made in the theory of quarkonium production in
hadronic collisions.


title:
Radiative Parton Model Analysis of Polarized Deep Inelastic Lepton
  Nucleon Scattering

abstract:
  A leading order QCD analysis of spin asymmetries in polarized deep inelastic
lepton nucleon scattering is presented within the framework of the radiative
parton model. Two resulting sets of plausible leading order spin dependent
parton distributions are presented, respecting the fundamental positivity
constraints down to the low resolution scale $Q^2=\mu_{LO}^2=0.23$ GeV$^2$. The
$Q^2$ dependence of the spin asymmetries $A_1^{p,n,d}(x,Q^2)$ is investigated
in the range $1 \leq Q^2 \leq 20$ GeV$^2$ and shown to be non-negligible for
$x$-values relevant for the analysis of present data and possibly forthcoming
data at HERA.


title:
Gravitationally--Induced Three--Flavor Neutrino Oscillations as a
  Possible Solution to the Solar Neutrino Problem

abstract:
  Neutrinos can undergo flavor--oscillations if they possess flavor--dependent
couplings to the surrounding gravitational field (the VEP mechanism). The
neutrino fields can be massless, in accord with the Minimal Standard Model, but
at the expense of the Einstein Equivalence Principle. We show that it is
possible to explain the observed Solar Neutrino data from the various
experiments using the VEP solution in a realistic three--generation framework,
and further note how the three--flavor model can offer larger allowed regions
of parameter space over the two--flavor models.


title: Non-perturbative structure of the nucleon

abstract:
  Chiral perturbation theory is the effective field theory of the standard
model. In this talk, I discuss some applications of this framework to the
pion--nucleon system. These are chiral corrections to the S--wave pion--nucleon
scattering lengths, the reaction $\pi N \to \pi \pi N$ at threshold and
low--energy theorems in $\pi^0$ photoproduction.


title: Effective Hamiltonian for Scalar Theories in the Gaussian Approximation

abstract:
  We use a Gaussian wave functional for the ground state to reorder the
Hamiltonian into a free part with a variationally determined mass and the rest.
Once spontaneous symmetry breaking is taken into account, the residual
Hamiltonian can, in principle, be treated perturbatively. In this scheme we
analyze the $O(1)$ and $O(2)$ scalar models. For the $O(2)$--theory we first
explicitly calculate the massless Goldstone excitation and then show that the
one-loop corrections of the effective Hamiltonian do not generate a mass.


title: Nonfactorizable contributions to weak $D \to PV$ decays

abstract:
  We investigate nonfactorizable contributions to two-body hadronic decays of
the charmed mesons to a pseudoscalar meson and a vector meson in
Cabibbo-favored mode. Employing SU(3)-flavor symmetry for the nonfactorizable
matrix elements, we obtain branching ratios of the decays in consistent
agreement with experiment.


title: A low \alpha_s: Hint of new physics at the GUT scale?

abstract:
  In a SUSY GUT having an extra reverse doublet-triplet splitting near the GUT
scale, where the mass of an extra doublet is greater than the mass of an extra
triplet by two orders of magnitude, a low prediction of $\alpha_s$ can be
achieved through threshold corrections via the heavy scalars in the fundamental
representations, making the prediction consistent with the values being
suggested by low energy measurements. We implement this mechanism in a SUSY
SU(5) GUT minimally extended to suppress Higgsino mediated proton decay. We
also point out that as a consequence of this extension a natural scenario
arises with a large hierarchy in Yukawa couplings ($ \lambda_t / \lambda_b \sim
40$). An experimental low value of $\alpha_s(m_Z)$ along with the
non-observation of dimension-five proton decay modes at SuperKamiokande
detector will favor such an extension of the SUSY SU(5) GUT over the minimal
case.


title: The electro-magnetic Form Factors of the Proton in Chiral Soliton Models

abstract:
  The electro-magnetic form factors of the proton are calculated in a chiral
soliton model with relativistic corrections. The magnetic form factor $G_M$ is
shown to agree well with the new SLAC data for spacelike $Q^2$ up to 30
(GeV/c)$^2$ if superconvergence is imposed. The direct continuation through a
Laurent series to the timelike region above the physical threshold is in fair
agreement with the presently available set of data. The electric form factor
$G_E$ is dominated by a zero in the few (GeV/c)$^2$ region which appears to be
in conflict with the SLAC data.


title:
Recent Developments in one and two Pion Production in Elementary
  Reactions and Few Body Systems

abstract:
  In this talk we cover several issues concerning pion production. The first
one is the p p ----> p p pi^0 reaction where an alternative explanation based
on the off shell extrapolation of the pi N amplitude is offered. A recent model
for the gamma N ----> pi pi N reaction is presented and a new kind of exchange
current is constructed from it which allows one to address problems like double
Delta photoproduction from the deuteron. Finally the (gamma, pi pi) reaction in
nuclei is studied and shown to be highly sensitive to the renormalization of
the pions in nuclei.


title: Gamma Ray Astronomy with Underground Detectors

abstract:
  Underground detectors measure the directions of up-coming muons of neutrino
origin. They can also observe down-going muons made by gamma rays in the
Earth's atmosphere. Although gamma ray showers are muon-poor, they produce a
sufficient number of muons to detect the sources observed by GeV and TeV
telescopes. With a threshold higher by one hundred and a probability of muon
production of about $1\%$ for the shallower AMANDA and Lake Baikal detectors,
these instruments can, for a typical GRO source, match the detection efficiency
of a GeV satellite detector since their effective area is larger by a factor
$10^4$. The muons must have enough energy for accurate reconstruction of their
direction. Very energetic muons on the other hand are rare because they are
only produced by higher energy gamma rays whose flux is suppressed by the
decreasing flux at the source and by absorption on interstellar light. We show
that there is a window of opportunity for muon astronomy in the 100~GeV energy
region which nicely matches the threshold energies of the AMANDA and Lake
Baikal detectors.


title: Perturbative Gluon Resummation of the Top Quark Production Cross Section

abstract:
  We present a calculation of the total cross section for top quark production
based on a new perturbative resummation of gluon radiative corrections to the
basic QCD subprocesses. We use Principal Value Resummation to calculate all
relevant large threshold corrections. Advantages of this method include its
independence from arbitrary infrared cutoffs and specification of the
perturbative regime of applicability. For $p\bar{p}$ collisions at
center-of-mass energy $\sqrt{s}=1.8$TeV and a top mass of 175 GeV, we compute
$\sigma(t\bar{t})=5.52^{+0.07}_{-0.45}pb$.


title: Lifetimes of Heavy-Flavour Hadrons -- Whence and Whither?

abstract:
  A theoretical treatment for the weak decays of heavy-flavour hadrons has been
developed that is genuinely based on QCD. Its methodology as it applies to
total lifetimes and the underlying theoretical issues are sketched. Predictions
are compared with present data. One discrepancy emerges: the beauty baryon
lifetime appears to be significantly shorter than expected. The ramifications
of those findings are analyzed in detail.


title:
Quantum Field Kinetics of QCD: Quark-Gluon Transport Theory for
  Lightcone Dominated Processes

abstract:
  A quantum kinetic formalism is developed to study the dynamical interplay of
quantum and statistical-kinetic properties of non-equilibrium multi-parton
systems produced in high-energy QCD processes. The approach provides the means
to follow the quantum dynamics in both space-time and energy-momentum, starting
from an arbitrary initial configuration of high-momentum quarks and gluons.
Using a generalized functional integral representation and adopting the
`closed-time-path' Green function techniques, a self-consistent set of
equations of motions is obtained: a Ginzburg-Landau equation for a possible
color background field, and Dyson-Schwinger equations for the 2-point functions
of the gluon and quark fields. By exploiting the `two-scale nature' of
light-cone dominated QCD processes, i.e. the separation between the quantum
scale that specifies the range of short-distance quantum fluctuations, and the
kinetic scale that characterizes the range of statistical binary inter-
actions, the quantum-field equations of motion are converted into a correspon-
ding set of `renormalization equations' and `transport equations'. The former
describe renormalization and dissipation effects through the evolution of the
spectral density of individual, dressed partons, whereas the latter determine
the statistical occurrence of scattering processes among these dressed partons.
The renormalization equations and the transport equations are coupled, and
hence must be solved self-consistently. This amounts to evolving the
multi-parton system, from a specified initial configuration, in time and full
7-dimensional phase-space. This description provides a proba- bilistic
interpretation and is therefore of important practical value for the solution
of the dynamical equations of motion, e.g. by Monte Carlo simulation.


title:
Infra-red fixed point structure of soft supersymmetry breaking mass
  terms

abstract:
  We show that the soft SUSY breaking mass terms may have infra-red stable
fixed points at which they are related to the gaugino masses and argue that in
a generic unification these masses should lie close to their fixed points. We
consider the implications for the family dependence of squark and slepton
masses and the related flavour changing neutral currents and determine
conditions under which models with flavour changing couplings and masses at a
high scale may lead to a family independent effective theory at low scales. The
analysis is illustrated for a variety of models for which we compute both the
fixed point structure and determine the rate of approach to the fixed point.


title: The Interpretation of Rapidity Gaps at Hera

abstract:
  In leading twist deep inelastic $ep$ scattering, the virtual photon
interaction is fast compared to the time scale of soft color rearrangement. We
compare the Pomeron exchange model, in which a neutral cluster is preformed,
with a gluon exchange model, in which color is exchanged after the hard
interaction. We find several features of the DIS data and of data on exclusive
hard processes that favor a gluon exchange scenario. If correct, the postulate
of soft color interactions between the produced ($q\bar q$) system and the
target has important implications for other processes. In particular, this may
explain the puzzles of charmonium hadroproduction.


title: Fermion mass prediction from Infra-red fixed points

abstract:
  We argue that in a wide class of theories the fermion and soft supersymmetry
breaking mass structure is largely determined by the infra-red fixed point
structure of the theory lying beyond the \smp We show how knowlege of the
symmetries and multiplet content of this theory is sufficient to determine the
infra-red structure, illustrating the idea for the case of a simple abelian
family symetry. The resulting structure determines the fermion masses and
mixing angles in terms of a restricted number of parameters.


title: Nondegenerate Fermions in the Background of the Sphaleron Barrier

abstract:
  We consider level crossing in the background of the sphaleron barrier for
nondegenerate fermions. The mass splitting within the fermion doublets allows
only for an axially symmetric ansatz for the fermion fields. In the background
of the sphaleron we solve the partial differential equations for the fermion
functions. We find little angular dependence for our choice of ansatz. We
therefore propose a good approximate ansatz with radial functions only. We
generalize this approximate ansatz with radial functions only to fermions in
the background of the sphaleron barrier and argue, that it is a good
approximation there, too.


title: Strange Nucleons and Hyperons as Chiral Solitons in the NJL Model

abstract:
  In the chirally symmetric Nambu--Jona-Lasinio model baryons are described as
chiral solitons of mesonic quark--antiquark bound states. Hyperons are
investigated in two complementary pictures: the bound state approach of Callan
and Klebanov and the collective approach of Yabu and Ando. The latter is used
to compute the strange vector form factors of the nucleon providing estimates
for the strange electric mean square radius and the strange magnetic moment of
the nucleon.


title: Quasi Goldstone Fermion As a Sterile Neutrino

abstract:
  The existence of sterile neutrino is hinted by simultaneous explanation of
diverse neutrino anomalies. We suggest that the quasi Goldstone fermions (QGF)
arising in supersymmetric theory as a result of spontaneous breaking of global
symmetry like the Peccei-Quinn symmetry or the lepton number symmetry can play
a role of the sterile neutrino. The smallness of mass of QGF ($m_S \sim
10^{-3}-10$ eV) can be related to the specific choice of superpotential or
K\"ahler potential (e.g., no-scale kinetic terms for certain superfields).
Mixing of QGF with neutrinos implies the $R$-parity violation. It can proceed
via the coupling of QGF with the Higgs supermultiplets or directly with the
lepton doublet. A model which accounts for the solar and atmospheric anomalies
and the dark matter is presented.


title:
Radiative Corrections to $\gamma\gamma\to t \bar t$ in the Electroweak
  Standard Model

abstract:
  The cross-section for $\gamma\gamma\to t \bar t$ with arbitrary polarized
photons is calculated within the electroweak Standard Model including the
complete virtual and soft-photonic $O(\alpha)$ corrections. We present a
detailed numerical discussion of the radiative corrections with particular
emphasis on the purely weak corrections. These are usually of the order of
1--10\% for energies up to 1 TeV. For unpolarized or equally polarized photons
they reach almost 10\% close to threshold. The large corrections cannot be
traced back to a universal origin like the running of $\alpha$ or the
$\rho$-parameter. Apart from the energy region around the Higgs resonance
$(\gamma\gamma\to H^*\to t\bar t)$ the weak corrections are widely independent
of the Higgs-boson mass.


title: On final-state effects in t-tbar production at threshold

abstract:
  We apply the relativistic Bethe-Salpeter formalism to the calculation of
final-state effects in the production of a t-tbar pair at threshold. We find
that final-state rescattering does not affect the momentum distribution of the
t-tbar pair to lowest order in the strong coupling constant. This result
correctly extends earlier results based on the non-relativistic
Lippmann-Schwinger equation.


title:
Semileptonic Decays of Bottom and Charm Baryons within Relativistic
  Quark Model

abstract:
  The results for observables of semileptonic decays of bottom and charm
baryons (Isgur-Wise functions, decay rates, distributions, asymmetry
parameters) are given within relativistic quark model. A comparison with recent
experimental data (CLEO Collaboration) is made.


title:
Impact of Atomic Parity Violation Measurements on Precision Electroweak
  Physics

abstract:
  The impact of atomic parity violation experiments on determination of the
weak mixing parameter $\sin^2 \theta$ and the Peskin-Takeuchi parameters $S$
and $T$ is reassessed in the light of recent electroweak measurements at LEP,
SLAC, and Fermilab. Since the weak charge $Q_W$ provides unique information on
$S$, its determination with a factor of four better accuracy than present
levels can have a noticeable effect on global fits. However, the measurement of
$\Delta Q_W / Q_W$ for two different isotopes provides primarily information on
$\sin^2 \theta$. To specify this quantity to an accuracy of $\pm 0.0004$,
comparable to that now provided by other electroweak experiments, one would
have to determine $\Delta Q_W/Q_W$ in cesium to about 0.1\% of its value, with
comparable demands for other nuclei. The relative merits of absolute
measurements of $Q_W$ and isotope ratios for discovering effects of new gauge
bosons are noted briefly.


title: Construction of an SO(10) x U(1)_F Model of the Yukawa Interactions

abstract:
  We construct a supersymmetric $SO(10) \times U(1)_F$ model of the Yukawa
interactions at the grand unification scale from knowledge of a
phenomenological set of mass matrices obtained by a previous bottom-up
approach. The $U(1)_F$ family symmetry determines the textures for the Majorana
and generic Dirac mass matrices, while the $SO(10)$ symmetry relates each
particular element of the up, down, neutrino and charged lepton Dirac matrices.
The dominant second and third family contributions in the Dirac sector are
renormalizable, while the remaining contributions to the Dirac mass matrices
are of higher order, restricted by the $U(1)_F$ family symmetry to a small set
of tree diagrams, and mainly complex-symmetric. The tree diagrams for the
Majorana mass matrix are all non-renormalizable and of progressively
higher-order, leading to a nearly geometrical structure. Pairs of ${\bf 1, 45,
10}$ and ${\bf 126}$ Higgs representations enter with those having large vacuum
expectation values breaking the symmetry down to $SU(3)_c \times SU(2)_L \times
U(1)_Y$ near the grand unification scale. In terms of 12 parameters expressed
as the Yukawa couplings times vacuum expectation values for the Higgs
representations employed, a realistic set of 15 quark and lepton masses
(including those for the 3 heavy righthanded Majorana neutrinos) and 8 mixing
parameters emerges for the neutrino scenario involving the non-adiabatic
conversion of solar neutrinos and the depletion of atmospheric muon-neutrinos
through oscillations into tau-neutrinos.


title: Constraints on Supersymmetric Theories from $\mu\to e,\gamma$

abstract:
  In the absence of any additional assumption it is natural to conjecture that
sizeable flavour-mixing mass entries, $\Delta m^2$, may appear in the mass
matrices of the scalars of the MSSM, i.e. $\Delta m^2\sim O(m^2)$. This flavour
violation can still be reconciled with the experiment if the gaugino mass,
$M_{1/2}$, is large enough, leading to a {\em gaugino dominance} framework
(i.e. $M_{1/2}^2\gg m^2$), which permits a remarkably model--independent
analysis. We study this possibility focussing our attention on the
$\mu\rightarrow e,\gamma$ decay. In this way we obtain very strong and general
constraints, in particular $\frac{M_{1/2}^2}{\Delta m}\simgt 34\ {\rm TeV}$. On
the other hand, we show that our analysis and results remain valid for values
of $m^2$ much larger than $\Delta m^2$, namely for $\frac{\Delta
m^2}{m^2}\simgt \frac{m^2} {10\ {\rm TeV^2}}$, thus extending enormously their
scope of application. Finally, we discuss the implications for superstring
scenarios.


title: New Tools for Low Energy Dynamical Supersymmetry Breaking

abstract:
  We report the construction of large new classes of models which break
supersymmetry dynamically. We then turn to model building. Two of the principal
obstacles to constructing simple models of dynamical supersymmetry breaking are
the appearance of Fayet-Iliopoulos D terms and difficulties in generating a
$\mu$ term for the Higgs fields. Among the new models are examples in which
symmetries prevent the appearance of Fayet-Iliopoulos terms. A gauge singlet
field, that may play a role in explaining the hierarchy in quark and lepton
parameters, can generate a suitable $\mu$ term. The result is a comparatively
simple model, with a low energy structure similar to that of the MSSM, but with
far fewer arbitrary parameters. We begin the study of the phenomenology of
these models.


title: Lepton Flavour Violations in SO(10) with large $\tan\beta$

abstract:
  In supersymmetric~SO(10) with large $\tan\beta$ and Yukawa coupling
unification $\lambda_t=\lambda_b=\lambda_\tau$, we compute the rates for lepton
flavour violating processes. Experiments in progress or foreseen for $\mu\to
e\gamma$, $\mu\to e$ conversion (and the dipole moment of the electron) are
shown to provide very significant tests of the theory for all slepton masses up
to about $1\TeV$.


title: The Free Energy of Hot Gauge Theories with Fermions Through g^5

abstract:
  We compute the free energy density $F$ for gauge theories, with fermions, at
high temperature and zero chemical potential. In the expansion $F=T^4 [c_0+c_2
g^2+c_3 g^3+(c'_4\ln g+c_4)g^4+ (c'_5\ln g+c_5)g^5+O(g^6)]$, we determine
$c'_5$ and $c_5$ analytically by calculating two- and three-loop diagrams. The
$g^5$ term constitutes the first correction to the $g^3$ term and is for the
non-Abelian case the last power of $g$ that can be computed within perturbation
theory. We find that the $g^5$ term receives no contributions from overlapping
double-frequency sums and that $c'_5$ vanishes.


title:
Gauge independence of the bubble nucleation rate in theories with
  radiative symmetry breaking

abstract:
  In field theories where a metastable false vacuum state arises as a result of
radiative corrections, the calculation of the rate of false vacuum decay by
bubble nucleation depends on the effective potential and the other functions
that appear in the derivative expansion of the effective action. Beginning with
the Nielsen identity, we derive a series of identities that govern the gauge
dependence of these functions. Using these, we show, to leading nontrivial
order, that even though these functions are individually gauge-dependent, one
obtains a gauge-independent result for the bubble nucleation rate. Our formal
arguments are complemented by explicit calculations for scalar electrodynamics
in a class of $R_\xi$ gauges.


title:
Virtual Top Effects on Low-Mass Higgs Interactions at Next-to-Leading
  Order in QCD

abstract:
  We present the next-to-leading-order QCD corrections of O(alpha_s^2 G_F
M_t^2) to the low-M_H effective l^+l^-H, ZZH, and W^+W^-H interaction
Lagrangians in the high-M_t limit. In the on-shell scheme formulated with G_F,
the O(alpha_s^2 G_F M_t^2) corrections support the O(alpha_s G_F M_t^2) ones
and further increase the screening of the O(G_F M_t^2) terms. The coefficients
of (alpha_s/pi)^2 range from -6.847 to -16.201, being in line with the value
-14.594 recently found for Delta rho. All four QCD expansions converge
considerably more rapidly, if they are written with mu_t=m_t(mu_t), where
m_t(mu) is the MS-bar mass, rather than the pole mass, M_t.


title: Intensity-dependent pion-nucleon coupling and the Wroblewski relation

abstract:
  We propose an intensity-dependent pion-nucleon coupling Hamiltonian within a
unitary multiparticle-production model of the AABS type in which the pion field
is represented by the thermal-density matrix. Using this Hamiltonian, we
explain the appearance of the negative- binomial (NB) distribution for pions
and the well-known empirical relation, the so-called Wroblewski relation. The
Hamiltonian of our model is expressed linearly in terms of the generators of
the SU(1,1) group.


title:
Implications on two Higgs doublet models from the latest $b\to s\gamma$
  measurement and top discovery

abstract:
  The constraints on the two Higgs doublet model from the new experimental
bounds of $b\to s\gamma$ by CLEO and the latest published value of the top
quark mass by CDF and D0 are reanalyzed with the effective Lagrangian covering
the full QCD corrections from the energy scale of top quark to that of bottom.
The reanalysis result shows that the constraints become more stringent than
that of the earlier analysis, i.e. a bigger region of the parameter space of
the model is ruled out.


title: Galactic Halos As Boson Stars

abstract:
  We investigate the boson star with the self-interacting scalar field as a
model of galactic halos. The model has slightly increasing rotation curves and
allows wider ranges of the mass($m$) and coupling($\lambda$) of the halo dark
matter particle than the non-interacting model previously
suggested(ref.\cite{sin1}). Two quantities are related by
$\lambda^{\frac{1}{2}} (m_p/m)^2\st{>}{\sim} 10^{50}$.


title: Probing Supergravity Grand Unification in the Brookhaven g-2 Experiment

abstract:
  A quantitative analysis of $\amu\equiv{1\over 2}(g-2)_\mu$ within the
framework of Supergravity Grand Unification and radiative breaking of the
electro-weak symmetry is given. It is found that $a_{\mu}^{SUSY}$ is dominated
by the chiral interference term from the light chargino exchange, and that this
term carries a signature which correlates strongly with the sign of $\mu$. Thus
as a rule $a_{\mu}^{SUSY}>0$ for $\mu>0$ and $a_{\mu}^{SUSY}<0$ for $\mu<0$
with very few exceptions when tan$\beta\sim 1$. At the quantitative level it is
shown that if the E821 BNL experiment can reach the expected sensitivity of
$4\times 10^{-10}$ and there is a reduction in the hadronic error by a factor
of four or more, then the experiment will explore a majority of the parameter
space in $ m_0-m_{\tilde g}$ plane in the region $m_0\lsim 400$ GeV, $m_{\tilde
g}\lsim 700$ GeV for $\tanbeta \gsim 10$ assuming the experiment will not
discard the Standard Model result within its $2\sigma$ uncertainty limit. For
smaller $\tanbeta$, the SUSY reach of E821 will still be considerable. Further,
if no effect within $2 \sigma$ limit of the Standard Model value is seen, then
large $\tanbeta$ scenarios will be severely constrained within the current
naturalness criterion, ie., $m_0, m_{\tilde g}\lsim 1$ TeV.


title:
On the observation of $e^+e^-\to b \bar{b}Z^0$ at LEP II with two Higgs
  doublets

abstract:
  We study possible observational effects of the two Higgs doublets in the
$e^+e^- \to b \bar{b} Z^0$ at the LEP II energy. We have found that the
observational values can be obviously different from that predicted by the
minimal Standard Model (MSM), but the results depend on the parameters of the
extended model. The possibilities of the observation are discussed in some
details.


title:
Sharpening up the Charged Higgs Boson Signature using Tau Polarization
  at LHC

abstract:
  The opposite states of the $\tau$ polarization resulting from the charged
Higgs boson and the $W$ boson decays can be exploited to enhance the $H^\pm$
signal in the inclusive 1-prong hadronic decay channel of $\tau$. We suggest
practical methods of sharpening up the $H^\pm$ signature in the top quark decay
at LHC using this idea. As a result one can carry on the charged Higgs boson
search to within $\sim 20 GeV$ of the parent top quark mass over the full
parameter space of the MSSM.


title: Can gravity play a role at the electroweak scale?

abstract:
  A connection is made between a model for strongly interacting vector bosons
and the spontaneously broken theory of gravity. The theory contains effectively
no Higgs particle, but should have strong interactions at the electroweak
scale. Some speculations about the nature of these interactions and possible
experimental signatures are discussed.


title:
Disoriented Chiral Condensates: A Dynamical Simulation in the
  (2+1)-Dimensional Gross-Neveu Model

abstract:
  We simulate the formation and growth of disoriented chiral condensate (DCC)
regions which follow the expansion of a high energy density region into the
``cold'' vacuum. The numerical study is based on the one-loop effective
potential for the massive 2+1-dimensional Gross-Neveu model. We pay attention
to the setting of the initial conditions and to determining which parameters
are relevant for a strong amplification of the pion field. We find that the
size of the ``hot'' source plays a significant role. For large enough source
radii, we observe strong correlation phenomena, corresponding to the growth of
large regions where the pion field oscillates along a given direction. We give
our results in terms of the $\theta$ angle which defines the DCC
disorientation, of the other $O(4)$ angles distributions, of the local ratios
$R_{a}=\pi_{a}^{2}/{\vec{\pi}}^2$ $(a=1,2,3)$, and of the energies associated
with the fields at representative times.


title: Charm lifetime

abstract:
  A review of the charmed meson and baryon lifetimes is presented. Our
knowledge of charmed particle lifetimes has greatly improved over the past two
years, a crucial r\^ole having been played by the E687 experiment at Fermilab,
which has almost quadrupled the samples of $D$ mesons. The lifetime ratios
$\tau(D^+)/\tau(D^0)$ and $\tau(D_s^+)/\tau(D^0)$ are now known with an
accuracy of 1.7\% and 3.7\% respectively. In the baryon sector the statistics
is still limited, but the experimental results on $\Lambda_c^+$, $\Xi_c^0$ and
$\Xi_c^+$ exhibit a clear pattern of lifetime hierarchy, as expected from
simple theoretical arguments. The first measurement of $\tau(\Omega_c^0)$ from
E687 is also presented to complete the charmed baryon lifetime picture. The
more accurate experimental scenario can provide information on non-perturbative
QCD effects and the hadronic matrix elements.


title: Electromagnetic detection of axions

abstract:
  Photon-to-axion conversions in the static electromagnetic fields are
reconsidered in detail by using the Feynman diagram techniques. The
differential cross sections are presented for the conversions in the presence
of the electric field of the flat condenser as well as in the magnetic field of
the solenoid. Based on our results a laboratory experiment for the production
and the detection of the axions is described. This experiment will exploit the
axion decay constant as well as the axion mass.


title: Just-So Oscillation: as Just as MSW?

abstract:
  The neutrino long wavelength (just-so) oscillation is reconsidered as a
solution to the solar neutrino problem. In the light of the presently updated
results of the four solar neutrino experiments, the data fit in the just-so
scenario substantially improves and becomes almost as good as in the MSW
scenario. Surprising result of our analysis is that best fit is achieved when
the oscillation occurs only between two neutrino states: switching on the
oscillation into third neutrino increases the $\chi^2$ value. Namely, we
consider the vacuum oscillation scenario in the three-neutrino system (4
parameters) and find out that the $\chi^2$ minimum is always achieved in the
{\it two} parameter subspace in which actually only {\it two} neutrino states
oscillate. This holds in the framework of any solar model with relaxed
prediction of the various neutrino fluxes. The possible theoretical
implications of this observation are also discussed.


title: Production of vector mesons by real and virtual photons at high energies

abstract:
  A model based on Reggeon field theory is used for the description of the
photo- and electroproduction of vector mesons ($\rho^0, \omega, \phi, J /\psi$)
on the proton. Its main feature is the dependence of the Pomeron intercept on
the virtuality of the photon. The few parameters of the model were determined
by fitting the total cross sections for real and virtual photons on the proton.
This allows a parameter-free description of the energy dependence of vector
meson production. Very good agreement with the existing high energy data is
obtained.


title:
Partial $U(1)_A$ Restoration and $\eta$ Enhancement in High-Energy
  Heavy-Ion Collisions

abstract:
  We calculate the thermally averaged rates for the $\eta$-$\pi$ conversion and
$\eta$ scattering using the Di Vecchia-Veneziano model and t' Hooft model,
which incorporate explicitly the $U(1)_A$ anomaly. Assuming an exponential
suppression of the $U(1)_A$ anomaly, we also take into account the partial
restoration of $U(1)_A$ symmetry at high temperatures. We find that the
chemical equilibrium between $\eta$ and $\pi$ breaks up considerably earlier
than the thermal equilibrium. Two distinct scenarios for the $\eta$ freeze-out
are discussed and the corresponding chemical potentials are calculated. We
predict an enhancement of the thermal $\eta$-production as a possible signal of
the partial $U(1)_A$ restoration in high-energy heavy-ion collisions.


title:
Double Higgs Production at the Linear Colliders and the Probing of the
  Higgs Self-Coupling

abstract:
  We study double Higgs production in the $e^+ e^-$ and $\gamma \gamma$ modes
of the linear collider. It is also shown how one can probe the scalar potential
in these reactions. We discuss the effective longitudinal $W$ approximation in
$\gamma \gamma$ processes and the $W_L W_L$ luminosities in the two modes of a
high-energy linear collider. A generalised non-linear gauge-fixing condition,
which is particularly useful for tree-level calculations of electroweak
processes for the laser induced collider, is presented. Its connection with the
background-field approach to gauge fixing is given.


title: Consequences of Supergravity with Gauged $\rm U(1)_R$ Symmetry

abstract:
  The structure of gauged R supergravity Lagrangians is reviewed, and we
consider models with a hidden sector plus light fields of the MSSM. A simple
potential for the hidden sector is presented which has a global minimum with
zero cosmological constant and spontaneously broken SUSY and R-symmetry. The
$\rm U(1)_R$ vector multiplet acquires a Planck scale mass through the Higgs
mechanism, and it decouples at low energy. Due to very interesting
cancellations, the $\rm U(1)_R$ D-terms also drop out at low energy. Thus no
direct effects of the gauging of R-symmetry remain in the low energy effective
Lagrangian, and this result is model independent, requiring only that
R-symmetry be broken at the Planck scale and $<D> = 0$, where $D$ is the
auxiliary field of the $\rm U(1)_R$ vector multiplet. The low energy theory is
fairly conventional with soft SUSY breaking terms for the MSSM fields. As a
remnant of the gauging of R-symmetry, it also contains light fields, some
required to cancel R-anomalies and others from the hidden sector.


title: Gluon Fragmentation into Spin-Triplet S-Wave Quarkonium

abstract:
  The leading color-singlet contribution to the fragmentation function for a
gluon to split into spin-triplet S-wave quarkonium is presented. In the case of
charmonium, we find that this color-singlet term is always negligible compared
to the leading color-octet contribution.


title: Strange-Beauty Meson Production at $p\bar p$ Colliders

abstract:
  The production rates and transverse momentum distributions of the
strange-beauty mesons $B_s$ and $B_s^*$ at $p\bar p$ colliders are calculated
assuming fragmentation is the dominant process. Results are given for the
Tevatron in the large transverse momentum region, where fragmentation is
expected to be most important.


title: New Phenomena Beyond Both the Standard Model and MSSM

abstract:
  Signals for new, non-supersymmetric physics at hadron colliders are reviewed.
We focus on extended gauge sectors and new matter particles. {Presented at the
{\it 10th Topical Workshop on Proton-Antiproton Collider Physics}, Batavia, IL,
9-13 May, 1995}}


title:
BHAGENE3, a Monte Carlo Event Generator for Lepton Pair Production and
  Wide Angle Bhabha Scattering in $e^{+} e^{-}$ Collisions Near the Z-Peak

abstract:
  A new Monte Carlo event generator for wide angle Bhabha scattering and muon
pair production in $e^+e^-$ collisions is described. The program includes
complete one-loop electroweak corrections, and QED radiative corrections. The
O($\alpha$) QED correction uses the exact matrix element. Higher order QED
corrections are included in an improved soft photon approximation with
exponentiation of initial state radiation. Events are generated in the full
phase space of the final state including explicit mass effects in the region of
collinear mass singularities. The program is intended for centre of mass
energies around and above the Z peak and for Bhabha scattering at angles
greater than $10^{\circ}$ .


title: MSSM phenomenology in the large tanb regime

abstract:
  We discuss aspects of the low energy phenomenology of the MSSM, in the large
$\tan {\beta} $ regime. We explore the regions of the parameter space where the
$h_t$ and $h_b$ Yukawa couplings exhibit a fixed point structure, using
previous analytic solutions for these couplings. Expressions for the parameters
$A_{t}$ and $A_{b}$ and the renormalised soft mass terms are also derived,
making it possible to estimate analytically the sparticle loop -- corrections
to the bottom mass, which are important in this limit.


title:
The strange quark spin of the proton in semi-inclusive $\Lambda$
  leptoproduction

abstract:
  Considering the possible interpretation of the Ellis-Jaffe sum rule violation
that the strange quark in the polarized proton is remarkably polarized in the
opposite direction of the proton spin, we investigate its implication in the
semi-inclusive $\Lambda$ production in deep inelastic process with the electron
beam unpolarized and proton target polarized longitudinally. As a result, we
find that the measurement of the $\Lambda$ polarization in the process
considered can provide clean information about the strange quark spin
distribution in the proton.


title:
Effective Lagrangian of Thermal QED with External Magnetic Field and the
  Static Limit of the Polarization Operator

abstract:
  A low-temperature expansion of QED one-loop effective Lagrangian valid for a
wide range of parameters is presented in a form of finite sums of elementary
functions. Starting from the effective action components of the one-loop
polarization operator responsible for Hall conductivity and Debye screening are
obtained. It is shown that in a strong background magnetic field the Debye
radius depends on spatial direction.


title:
Can Large $u, d$ Quark Masses be Inferred from the $D_s \to n \pi$ decay
  rate?

abstract:
  The $D_s \rightarrow n \pi$ measured branching could lead to information on
$u, d$ quark masses if it is dominated by the (helicity suppressed) $D_s
\rightarrow u \bar d$ annihilation channel. The data would then suggest
anomalously high $m_u \approx m_d \approx 30$MeV masses. We find however that
$D_s \rightarrow u {\bar d} g$ can explain $\sum Br(D_s \rightarrow n \pi)$
with zero up and down quark masses. We also argue that the present $D_s
\rightarrow n \pi$ data may not even convincingly imply any annihilation
process whatsoever.


title: Precision tests of the electroweak interaction

abstract:
  The status of the electroweak Standard Model is reviewed in the light of
recent precision data and new theoretical results which have contributed to
improve the predictions for precision observables, together with the remaining
inherent theoretical uncertainties. Consequences for possible new physics are
also discussed.


title: Do psi(4040), psi(4160) signal Hybrid Charmonium?

abstract:
  We suggest that $\psi$ (4040) and $\psi$ (4160) are strong mixtures of ground
state hybrid charmonium at $\sim 4.1$ GeV and the $\psi (3S)$ of conventional
charmonium. The $\Gamma^{e^+e^-}$, masses and total widths of the $\psi(4040)$
and $\psi(4160)$ are in accord with this hypothesis. Their hadronic decays are
predicted to be dominated by the $\psi (3S)$ component and hence are
correlated. In particular we find a spin counting relation $\Gamma (4160
\rightarrow D_sD_s^*) \sim 4 \Gamma (4040 \rightarrow D_sD_s)$ due to their
common $\psi(3S)$ component. For $D$ and $D^*$ production, using $\psi(4040)$
branching ratios as input, we predict that the decay pattern of the
$\psi(4160)$ will be very different from that of the $\psi(4040)$. These
predictions may be tested in historical data from SPEAR, BES or at future
Tau-Charm Factories.


title: The lambda Phi^4 Miracle: lattice data and the zero-point potential

abstract:
  Recent lattice data for the effective potential of lambda Phi^4 theory fits
the massless one-loop formula with amazing precision. Any corrections are at
least 100 times smaller than is reasonable, perturbatively. This is strong
evidence for the "exactness conjecture" of Consoli and Stevenson.


title: Triple Electroweak Gauge-Boson Production at Fermilab Tevatron Energies

abstract:
  We calculate the three gauge-boson production in the Standard Model at
Fermilab Tevatron energies. At $\sqrt s=2$ TeV in $p\bar p$ collisions, the
cross sections for the triple gauge-boson production are typically of order 10
femtobarns (fb). For the pure leptonic final states from the gauge-boson decays
and with some minimal cuts on final state photons, the cross sections for $p
\bar p \rightarrow W^\pm \gamma\gamma, Z\gamma\gamma$ and $W^+W^- \gamma$
processes are of order a few fb, resulting in a few dozen clean leptonic events
for an integrated luminosity of 10 fb$^{-1}$. The pure leptonic modes from
other gauge-boson channels give significantly smaller rate. Especially, the
trilepton modes from $W^+W^-W^\pm$ and $t \bar t W^\pm \rightarrow W^+W^-W^\pm$
yield a cross section of order 0.1 fb if there is no significant Higgs boson
contribution. For a Higgs boson with $m_H^{} \simeq 2M_Z^{}$, the triple
massive-gauge-boson production rate could be enhanced by a factor of $4-6$.


title:
A model for the B ---> X_{s}+\gamma decay in the chromomagnetic
  background

abstract:
  We calculate the shape of the photon spectrum for $B\rightarrow X_{s}+\gamma$
decay in the presence of a background chromomagnetic field for the case of
SU(2) gauge group. The effect of the external field resembles the Zeeman effect
- the parton model peak is split into two slightly assymetric peaks, located
around the kinematic endpoint. We investigate the analytic properties of the
spectrum and calculate the total decay rate. This decay may serve as a model
for the investigation of gluon condensate effects and their influence on the
shape of the spectrum.


title: Four Top Production and Electroweak Symmetry Breaking

abstract:
  With the recent discovery of a heavy top quark $(m_t \approx 175 - 200$ GeV),
the top quark opens an window to electroweak symmetry breaking. We propose the
study of four-top, $t\bar t t\bar t$, production at hadronic supercolliders as
a probe to electroweak symmetry breaking.


title: Rare b and c Decays and the CKM Matrix

abstract:
  I report on developments in the experimental and phenomenological
understanding of the rare decays of mesons containing b and c quarks,
especially as they pertain to the understanding of the CKM matrix and the
testing of the standard model. Some related measurements are also discussed.


title:
Large uncertainties in the cross section of elastic $ W_L^+ W_L^- $
  scattering

abstract:
  The amplitudes for $2\rightarrow 2$ scattering processes involving
longitudinally polarized gauge bosons $( W_L^\pm, Z_L )$ and the Higgs boson
are analyzed up to two loops. Assuming $M_H >> M_W$, the trilinear Higgs
coupling, $\lambda v$, is dominant for energies of $\sqrt{s}$ < 1.5 -- 2 $M_H$.
For larger values of $\sqrt{s}$, the quartic coupling, $\lambda$, becomes
dominant, allowing for a simpler calculation of higher-order corrections. The
high-energy amplitudes display a large logarithmic dependence on $\sqrt{s}$
which can be resummed using renormalization group techniques. The resummation
of leading-log terms is sufficient for Higgs masses of less than 350 GeV. For
350 < $M_H$ < 450 GeV, a next-to-leading-log resummation is necessary. For even
larger values of $M_H$, the perturbative approach fails completely since
two-loop terms become in magnitude larger than one-loop terms. Choosing the
$\overline{{\rm MS}}$ renormalization scheme instead of the OMS scheme, the
coefficients of the perturbative series increase in magnitude, making the
breakdown of perturbation theory even more apparent. In conclusion, the
Standard Model cross sections presented here have very large uncertainties if
$M_H\gtrsim 450$ GeV and $\sqrt{s} \gtrsim 2 M_H$, reducing the sensitivity to
contributions from new physics significantly.


title: Reheating and Thermalization, Linear Vs. Non-Linear Relaxation

abstract:
  We consider the case of a scalar field, the inflaton, coupled to both lighter
scalars and fermions, and the study the relaxation of the inflaton via particle
production in both the linear and non-linear regimes. This has an immediate
application to the reheating problem in inflationary universe models. The
linear regime analysis offers a rationale for the standard approach to the
reheating problem, but we make a distinction between relaxation and
thermalization. We find that particle production when the inflaton starts in
the {\it non-linear} region is typically a far more efficient way of
transfering energy out of the inflaton zero mode and into the quanta of the
lighter scalar than single particle decay. For the non-linear regime we take
into account self-consistently the evolution of the expectation value of the
inflaton field coupled to the evolution of the quantum fluctuations. An
exhaustive numerical analysis reveals that the distribution of produced
particles is far from thermal, and the effect of open channels. In the
fermionic case, Pauli blocking begins to hinder the transfer of energy into the
fermion modes very early on in the evolution of the inflaton. We examine the
implications of our results to the question of how to calculate the reheating
temperature of the universe after inflation.


title:
Can We Observe Weak Anomalous Couplings of Heavy Quarks Through Three
  Jet Events?

abstract:
  The rates and corresponding jet distributions for the decay $Z\to b\bar bg$
and the process $e^+e^-\to t\bar tg$ may be sensitive to anomalous dipole-like
couplings of heavy quarks to the photon and $Z$. In the $b$-quark case, after
updating our previous analysis on the constraints imposed by current
experiments on $Zb\bar b$ anomalous couplings, we show that the variation of
these couplings within their presently allowed ranges leads to rather minor
modifications to the Standard Model expectations for $Z\to b\bar bg$
observables. In the $t$-quark case, significant deviations from the Standard
Model predictions for $t\bar tg$ production at the Next Linear Collider are
possible.


title: Flavor Changing Neutral Scalar Currents at $\mu^+\mu^-$ Colliders

abstract:
  The prospect of observing the flavor changing decay $\fH\to t\bar c$ of a
neutral Higgs boson produced via $s$-channel and its subsequent decay into
$t\bar c$ is considered at a $\mu^+\mu^-$ collider. Numerical estimates are
given in the context of a two Higgs doublet model with flavor changing
couplings. It is found that for many values of the model parameters such {\it
tree-level} flavor changing decays will be produced at an observable level. In
addition studies of the helicity of the top will allow the determination of the
relative strengths of the flavor changing Higgs couplings and these may be
measured with about $10^3$ events.


title: Three-Body Decays of the Susy Higgs Bosons

abstract:
  In this talk I discuss three-body decays of the SUSY Higgs bosons which
proceed via intermediate two-body states in which one of the particles is
off-mass-shell. Some of these decays will be shown to have substantial
branching ratios in some range of the SUSY parameter space.


title:
The reaction $\pi N \to \pi \pi N$ at threshold in chiral perturbation
  theory

abstract:
  In the framework of heavy baryon chiral perturbation theory, we give thIn the
framework of heavy baryon chiral perturbation theory, we give the chiral
expansion for the $\pi N \to \pi \pi N$ threshold amplitudes $D_1$ and $D_2$ to
quadratic order in the pion mass. The theoretical results agree within one
standard deviation with the empirical values. We also derive a relation between
the two threshold amplitudes of the reaction $\pi N \to \pi \pi N$ and the $\pi
\pi$ S--wave scattering lengths, $a_0^0$ and $a_0^2$, respectively, to order
${\cal O}(M_\pi^2)$. We show that there are uncertainties mostly related to
resonance excitation which make an accurate determination of the $\pi \pi$
scattering length $a_0^0$ from the $\pi \pi N$ threshold amplitudes at present
very difficult. The situation is different in the $\pi \pi$ isospin two final
state. Here, the chiral series converges and one finds $a_0^2 = -0.031 \pm
0.007$ consistent with the one--loop chiral perturbation theory prediction.


title:
Supersymmetric contribution to the quark-lepton universality violation
  in charged currents

abstract:
  The supersymmetric one-loop contribution to the quark-lepton universality
violation in the low-energy charged current weak interactions is studied. It is
shown that the recent experimental data with the 1-$\sigma$ deviation from the
universality may be explained by the existence of the light sleptons
($<220$GeV) and relatively light chargino and neutralinos ($<600$GeV) with
significant gaugino components. The sign of the universality violation is
briefly discussed.


title:
Electroweak Radiative Corrections To Polarized M{\o}ller Scattering
  Asymmetries

abstract:
  One loop electroweak radiative corrections to left-right parity violating
M{\o}ller scattering ($e^-e^-\to e^-e^-$) asymmetries are presented. They
reduce the standard model (tree level) prediction by 40$\pm 3$ \% where the
main shift and uncertainty stem from hadronic vacuum polarization loops. A
similar reduction also occurs for the electron-electron atomic parity violating
interaction. That effect can be attributed to an increase of
$\sin^2\theta_W(q^2)$ by $3\%$ in running from $q^2=m_Z^2$ to 0. The
sensitivity of the asymmetry to ``new physics'' is also discussed.


title: Effect of Binding in Deep Inelastic Scattering Revisited

abstract:
  In the Bjorken limit of the present theory of deep inelastic scattering (DIS)
the structure functions (up to anomalous dimensions and perturbative QCD
corrections) are described by the parton model. However the current operator in
the parton model does not properly commute with the representation operators
corresponding to the Lorentz group, space reflection and time reversal. To
investigate the violation of these symmetries in the parton model we consider a
model in which the current operator explicitly satisfies extended Poincare
invariance and current conservation. It is shown that due to binding of quarks
in the nucleon the Bjorken variable x no longer can be interpreted as the
internal light cone momentum fraction $\xi$ even in the Bjorken limit. As a
result, the data on DIS alone do not make it possible to determine the $\xi$
distribution of quarks in the nucleon. We also consider a qualitative
explanation of the fact that in the parton model the values given by the sum
rules exceed the corresponding experimental quantities while the quark
contribution to the nucleon momentum and spin is underestimated.


title:
Higher-order Coulomb Corrections to the Threshold e+ e- --> W+ W- Cross
  Section

abstract:
  The QED Coulomb correction is one of the most important corrections to the e+
e- --> W+ W- total cross section near threshold. We calculate these corrections
through second order, and discuss the implications for extracting M_W from a
threshold cross section measurement at LEP2. Analytic expressions are derived
in various kinematic limits.


title: Vortex Production in Non-Relativistic and Relativistic Media

abstract:
  We examine string (vortex) formation at a quench for a weakly-coupled global
U(1) theory when the excitation spectrum is non-relativistic. It is so similar
to vortex production in the corresponding relativistic plasma as to reinforce
arguments for the similarity of vortex production in the early universe and in
low-temperature many-body physics.


title: The Higgs Boson Mass from Precision Electroweak Data

abstract:
  We present a new global fit to precision electroweak data, including new low-
and high-energy data and analyzing the radiative corrections arising from the
minimal symmetry breaking sectors of the Standard Model (SM) and its
supersymmetric extension (MSSM). It is shown that present data favor a Higgs
mass of O(M_Z): M_H = 76+152-50 GeV. We confront our analysis with
(meta)stability and perturbative bounds on the SM Higgs mass, and the
theoretical upper bound on the MSSM Higgs mass. Present data do not
discriminate significantly between the SM and MSSM Higgs mass ranges. We
comment in passing on the sensitivity of the Higgs mass determination to the
values of alpha(M_Z) and alpha_s(M_Z).


title: Modelling form factors in HQET

abstract:
  We present a simple and straightforward method for relating the form factors
in HQET, as defined by the covariant trace formalism, to the overlaps of the
rest frame wave functions of the light degrees of freedom. We also point out
several inconsistencies present in recent calculations of the radiative rare
$B$ decays, and also show how these can be fixed even within the framework of
the non-relativistic quark model.


title: Possible sneutrino-pair signatures with R-parity breaking

abstract:
  If sneutrinos are the lightest supersymmetry partners and $R$-parity is not
conserved, the process $e^+e^- \to \tilde {\bar\nu} \tilde {\nu}$ can have
striking signatures due to the decay modes $\tilde{\nu}\to\ell^+\ell'^-$ or
$\tilde{\nu}\to q \bar q'$. We present cross section formulas and discuss event
rates and detection at the upgraded $e^+e^-$ collider LEP. Four-lepton signals
should be detectable up to sneutrino mass $\tilde {m}_\nu = 80$ GeV and maybe
beyond; four-jet signals should be detectable up to $\tilde {m}_\nu = 70$ GeV,
but would probably be obscured thereafter by $WW$ background.


title:
Neutrino Oscillations in the Early Universe with Nonequilibrium Neutrino
  Distributions

abstract:
  Around one second after the big bang, neutrino decoupling and $e^+$-$e^-$
annihilation distort the Fermi-Dirac spectrum of neutrino energies. Assuming
neutrinos have masses and can mix, we compute the distortions using
nonequilibrium thermodynamics and the Boltzmann equation. The flavor behavior
of neutrinos is studied during and following the generation of the distortion.


title:
Inclusive Prompt Photon Production in Hadronic Final States of $e^+e^-$
  Annihilation

abstract:
  We provide complete analytic expressions for the inclusive prompt photon
production cross section in hadronic final states of $e^+e^-$ annihilation
reactions through one-loop order in quantum chromodynamics perturbation theory.
Computed explicitly are direct photon production through first order in the
electromagnetic strength $\alpha_{em}$ and the quark-to-photon and
gluon-to-photon fragmentation contributions through first order in the strong
coupling $\alpha_s$. The full angular dependence of the cross sections is
displayed, separated into transverse $(1 +\cos ^2\theta _\gamma)$ and
longitudinal $(\sin ^2\theta_\gamma)$ components, where $\theta_\gamma$
specifies the direction of the photon with respect to the $e^+e^-$ collision
axis. We discuss extraction of fragmentation functions from $e^+e^-$ data.


title:
Magnetic Fields Produced by Phase Transition Bubbles in the Electroweak
  Phase Transition

abstract:
  The electroweak phase transition, if proceeding through nucleation and growth
of bubbles, should generate large scale turbulent flow, which in turn generates
magnetic turbulence and hence magnetic fields on the scale of turbulent flow.
We discuss the seeding of this turbulent field by the motion of the dipole
charge layers in the phase transition bubble walls, and estimate the strength
of the produced fields.


title:
A Nonperturbative Calculation of Basic Chiral QCD Parameters Within Zero
  Modes Enhancement Model of the QCD Vacuum. I

abstract:
  A new zero modes enhancement (ZME) model of the true QCD vacuum is breifly
described. It makes possible to analytically investigate and calculate
numerically low-energy QCD structure from first principles. Expressions of
basic chiral QCD parameters (the pion decay constant, the quark and gluon
condensates, the dynamically generated quark mass, etc) as well as the vacuum
energy density (up to the sign, by definition, the bag constant), suitable for
numerical calculations, have been derived. Solution to the Schwinger-Dyson (SD)
equation for the quark propagator in the infrared (IR) domain on the basis of
the ZME effect in QCD was used for this purpose. There are only two independent
quantities (free parameters) by means of which calculations must be done within
our approach. The first one is the integration constant of the above mentioned
quark SD equation of motion. The second one is a scale at which nonperturbative
effects begin to play a dominant role.


title:
A Nonperturbative Calculation of Basic Chiral QCD Parameters Within Zero
  Modes Enhancement Model of the QCD Vacuum. II

abstract:
  Basic chiral QCD parameters (the pion decay constant, the quark and gluon
condensates, the dynamically generated quark mass, etc) as well as the vacuum
energy density (up to the sign, by definition, the bag constant) have been
calculated from first principles within a recently proposed zero modes
enhancement (ZME) model of the true QCD vacuum. Our unique input data was
chosen to be the pion decay constant in the chiral limit as given by the chiral
perturbation theory at the hadronic level (CHPTh). In order to analyze our
numerical results we set a scale by two different ways. In both cases we obtain
almost the same numerical results for all chiral QCD parameters.
Phenomenological estimates of these quantites as well as vacuum energy density
are in good agreement with our numerical results. Complementing them by the
numerical value of the instanton contribution to the vacuum energy density, we
predict new, more realistic values for the vacuum energy density, the bag
constant and the gluon condensate.


title:
The b--->s{\gamma} constraint in effective supergravities from string
  theory

abstract:
  We study the constraints from the $b{\rightarrow}s{\gamma}$ decay in the
parameter space of effective supergravities from orbifold string theory and
with minimal supesymmetric particle content. Both the general dilaton-dominated
universal scenario as well as a non-universal scenario for the soft terms are
investigated. It is found that the recently reported CLEO upper and lower
bounds constrain the parameter space of the models under scrutiny. In
particular we find constraints on the values of the parameter $\tan{\beta}$ and
the gluino masses. In this class of string scenarios the negative sign of the
Higgs mixing parameter $\mu$, is phenomenologically preferred.


title: ELFE : an Electron Laboratory for Europe

abstract:
  This paper presents a brief overview of the physics with the 15-30~GeV
continuous beam electron facility proposed by the European community of nuclear
physicists to study the quark and gluon structure of hadrons.


title:
Probing quark compositeness at hadronic colliders : the case of
  polarized beams

abstract:
  A new handed interaction between subconstituents of quarks could be at the
origin of some small parity violating effects in one-jet inclusive production.
Within a few years, the Relativistic Heavy Ion Collider (RHIC) will be used as
a polarized proton-proton collider.
  In this context, we analyse the possibilities of disentangling some new
parity violating effects from the standard spin asymmetries which are expected
due to the Standard Model QCD-Weak interference. We also explore the
possibilities of placing some more stringent limits on the quark compositeness
scale $\Lambda$ thanks to measurements of such spin asymmetries.


title: Photo- and electroproduction of the eta and eta-prime mesons

abstract:
  We discuss the eta and eta prime photo- and electroproduction as a way to
probe the nucleon resonance structure.


title: ZZ' Mixing and Radiative Corrections at LEP I

abstract:
  We present a method for a common treatment of $Z'$ exchange, QED corrections,
and weak loops in $e^+ e^-$ annihilation. QED corrections are taken into
account by convoluting a hard-scattering cross section containing $\gamma,\ Z,$
and $Z'$ exchange. Weak corrections and $ZZ'$ mixing are treated simultaneously
by a generalization of weak form factors. Using the properly extended Standard
Model program for the $Z$ line shape, ZFITTER, we perform and compare two
different analyses of the 1990 LEP~I data in terms of theories based on the
E$_6$-group and in terms of LR-symmetric models. From the LEP~I data alone, the
$ZZ'$ mixing angle may be limited to $|\theta_M| \le 0.01$ and the $Z'$ mass to
$M_2 > 118$--148 GeV, depending on the model (95\%~CL).


title: Hadronization of $b\to c\bar cs$

abstract:
  The b -> c cbar s transition is usually believed to hadronize predominantly
in Bbar -> X_c Ds(*)- with the Ds(*)- originating from the virtual W. We
demonstrate in a variety of independent ways that other hadronization processes
cannot be neglected. The invariant mass of cbar s has sizable phase-space
beyond m_D+m_K. The rate for Bbar -> D Dbar Kbar X could be significant and
should not be ignored as was done in previous experimental analyses. We
estimate the number of charmed hadrons per B-decay, n_c, to be about 1.3 to
higher accuracy than obtained in previous investigations. Even though n_c is
currently measured to be about 1.1, observing a significant Bbar -> D Dbar Kbar
X would support n_c of about 1.3. Many testable consequences result, some of
which we discuss.


title: Limits on Pseudoscalar Bosons From Rare $Z$ Decays at LEP

abstract:
  Current LEP data on rare $Z$ decays constrain nonminimal technicolor models
that contain light neutral pseudo-Nambu-Goldstone bosons ($P^a$). We discuss
the production and decay of such particles, and show how LEP data on
$\gamma\gamma\gamma$, $\gamma + E\!\!\!/ $ and $\gamma+$hadrons constrain the
size of the technicolor gauge group and the strength of the $Z\gamma P^a$
coupling. The limits are then applied to several specific technicolor
scenarios.


title:
Extracting $\alpha$ from the CP Asymmetry in $B^0 \to \pi^+ \pi^-$
  Decays

abstract:
  The extraction of the CKM angle $\alpha$ from the asymmetry in $B^0 \to
\pi^+\pi^-$ vs ${\bar B^0} \to \pi^+\pi^-$ suffers from a currently unknown
penguin contribution. Experimentally, one can determine the magnitude and phase
of the CP asymmetry from a time-dependent analysis of tagged events, and the
average rate for $B^0$ and $\bar{B}^0$ decays to $\pi^+\pi^-$ from untagged
events. These measurements, together with the magnitudes and relative phase of
the tree and penguin diagrams, can in principle completely determine $\alpha$,
free of discrete ambiguities. We perform an error analysis on $\alpha$ given
assumptions on the values and uncertainties of both the measurements and
theoretical inputs.


title: Flavor Mixing, CP Violation and a Heavy Top

abstract:
  The recent analysis of the electroweak data at CDF indicates that the
constraint on the top quark mass is $m_t=174\pm 17 $GeV. We accommodate this
result in a new scheme of quark mass matrices in which two elements along the
the leading diagonal are non-vanishing and the other non-vanishing elements are
those due to nearest neighbour interactions. By comparing the quark mixing
matrix elements of our scheme with the experimentally determined Kobayashi-
Maskawa matrix elememts in the standard electroweak model, we find that the CP
violating phases ($\delta_1$ and $\delta_2$) in our model violate the CP
symmetry maximally.


title: QCD-like Hidden Sector Models without the Polonyi Problem

abstract:
  QCD-like hidden sector models of supersymmetry breaking are considered which
do not suffer from a cosmological problem due to the Polonyi field. Avoidance
of a light gluino leads to introduction of quasi-symmetry -- symmetry broken
explicitly only through gravitational effects.


title: One-loop corrections to five-parton amplitudes with external photons

abstract:
  Recently the calculations of all five-parton one-loop QCD amplitudes have
been completed. In this letter we describe how to get the corresponding
amplitudes with one gluon replaced by a photon and we give the explicit results
for the process $0 \to 2q 2Q 1\y$.


title: Unitarity violation in non-abelian Pauli-Villars regularization

abstract:
  We regularize QCD using the combination of higher covariant derivatives and
Pauli-Villars determinants proposed by Slavnov. It is known that for pure
Yang-Mills theory the Pauli-Villars determinants generate unphysical
logarithmic radiative corrections at one loop that modify the beta function.
Here we prove that when the gauge fields are coupled to fermions so that one
has QCD, these unphysical corrections translate into a violation of unitarity.
We provide an understanding of this by seeing that Slavnov's choice for the
Pauli-Villars determinants introduces extra propagating degrees of freedom that
are responsible for the unitarity breaking. This shows that Slavnov's
regularization violates unitarity, hence that it should be rejected.


title: Photon Emission from a Parton Gas at Chemical Non-Equilibrium

abstract:
  We compute the hard photon production rate of a chemically non-equilibrated
quark-gluon plasma. We assume that the plasma is already thermally
equilibrated, i.~e. describable by a temperature, but with a phase-space
distribution that deviates from the Fermi/Bose distribution by a time dependent
factor (fugacity). The photon spectrum is obtained by integrating the photon
rate over the space-time evolution of the quark-gluon plasma. Some consequences
for ultrarelativistic heavy ion collisions are discussed.


title:
CP-violating asymmetries in top-quark production and decay in $e^+ e^-$
  annihilation within the MSSM

abstract:
  We obtain analytic formulae for the cross section of the sequential processes
of $e^+ e^- \to t \bar t$ and $t \to b l \nu$ in the laboratory frame where the
dependence on triple product correlations of the type ($\hat(q}_1 x \hat{q}_2 .
\hat{q}_3$), induced by CP violation both in the production and the decay are
explicitely shown. Different observables sensitive to CP violation are defined
and calculated in the Minimal Supersymmetric Standard Model (MSSM). The
observables sensitive to CP violation are of the order of $10^-3$. The
dependence on the masses of the supersymmetric particles is also shown.


title:
Vortex Production at Phase Transitions in Nonrelativistic and
  Relativistic Media

abstract:
  We examine string (vortex) formation at a quench for a weakly-coupled global
U(1) theory when the excitation spectrum is non-relativistic. It is so similar
to vortex production in the corresponding relativistic plasma as to reinforce
arguments for the similarity of vorheptex production in the early universe and
in low-temperature many-body physics.


title:
Form factor of the process \gamma^*\gamma^* -->\pi^o for small
  Virtuality of One of the Photons and QCD Sum Rules

abstract:
  We extend the QCD sum rule analysis of the \gamma^*\gamma^* -->\pi^o form
factor into the region where one of the photons has small virtuality: q^2 <<
Q^2 > 1 GeV^2. In this kinematics, one should perform an additional
factorization of short- and long-distance contributions. The extra
long-distance sensitivity of the three-point amplitude is described by
two-point correlators (bilocals), and the low-momentum dependence of the
correlators involving composite operators of two lowest twists is extracted
from auxiliary QCD sum rules. Our estimates for the form factor at q^2=0, Q^2 >
1 1 GeV^2 are in good agreement with existing experimental data.


title: The heavy top quark and right-handed currents

abstract:
  We consider a modification of the standard electroweak model with the third
quark generation and the $\tau$-lepton in vector representations of
$SU(2)\otimes U(1)_Y$ electroweak symmetry. This is a new way to implement
right-handed currents which are controlled by the usual Fermi constant, $G_F$,
the weak mixing angle, $\sin\theta_W$, and also by the right-handed mixing
matrices which survive when the Lagrangian density is written in terms of the
mass eigenstates. In this case there are also new CP violation phases.


title:
Scalar Mesons in a Relativistic Quark Model with Instanton-Induced
  Forces

abstract:
  In a relativistic quark model with linear confinement and an
instanton-induced interaction which solves the $\eta$-$\eta'$ puzzle, scalar
mesons are found as almost pure SU(3) flavor states. This suggests a new
interpretation of the scalar nonet: We propose that the recently discovered
$f_0(1500)$ is not a glueball but the scalar (mainly)--octet meson for which
the $K\bar{K}$ decay mode is suppressed. The mainly--singlet state is
tentatively identified with the $f_0(980)$. The isovector and isodoublet states
correspond to the $a_0(1450)$ and $K^{\ast}(1430)$, respectively.


title: Loop Expansion in Light-Cone $\phi^4$ Field Theory

abstract:
  A loop expansion is implemented based on the path integral quantization of
the light-cone $\phi^4$ field theory in 1+1 dimensions. The effective potential
as a function of the zero-mode field $\omega$ is calculated up to two loop
order and its derivative with respect to $\omega$ is used to determine the
vacuum expectation value of the field $\phi$. The critical coupling constant at
the spontaneous symmetry breakdown is consistent with that obtained in the
ordinary instant-form field theory. The critical exponents which describe the
behavior of the susceptibility and the vacuum expectation value of $\phi$ near
the critical point are evaluated from the effective potential. The one loop
diagrams for the connected Green's function are calculated in momentum space.
The relevant equal-time correlation function is shown to be closely related.


title: $B$ Decay into Light Gluinos

abstract:
  Flavor changing interactions of the gluino allow the $b$ quark to decay into
the strange quark plus a gluino pair if the gluino is in the ultra low mass
window below 1 GeV. In this case the enhancement of the nonleptonic $b$ decay
could explain the anomalous semileptonic branching ratio.


title: CP-Violating Profile of the Electroweak Bubble Wall

abstract:
  In any scenario of the electroweak baryogenesis, the profile of the CP
violating bubble wall, created at the first-order phase transition, plays an
essential role. We attempt to determine it by solving the equations of motion
for the scalars in the two-Higgs-doublet model at the transition temperature.
According to the parameters in the potential, we found three solutions. Two of
them smoothly connect the CP-violating broken phase and the symmetric phase,
while the other connects CP-conserving vacua but violates CP in the
intermediate region. We also estimate the chiral charge flux, which will be
turned into the baryon density in the symmetric phase by the sphaleron process.


title: Baryogenesis from Flat Directions of the Supersymmetric Standard Model

abstract:
  Baryogenesis from the coherent production of a scalar condensate along a flat
direction of the supersymmetric extension of the standard model (Affleck-Dine
mechanism) is investigated. Two important effects are emphasized. First,
nonrenormalizable terms in the superpotential can lift standard model flat
directions at large field values. Second, the finite energy density in the
early universe induces soft potentials with curvature of order the Hubble
constant. Both these have important implications for baryogenesis, which
requires large squark or slepton expectation values to develop along flat
directions. In particular, the induced mass squared must be negative. The
resulting baryon to entropy ratio is very insensitive to the details of the
couplings and initial conditions, but depends on the dimension of the
nonrenormalizable operator in the superpotential which stabilizes the flat
direction and the reheat temperature after inflation. Unlike the original
scenario, an acceptable baryon asymmetry can result without subsequent entropy
releases. In the simplest scenario the baryon asymmetry is generated along the
$LH_u$ flat direction, and is related to the mass of the lightest neutrino.


title:
Longitudinal/Goldstone boson equivalence and phenomenology of probing
  the electroweak symmetry breaking

abstract:
  We formulate the equivalence between the longitudinal weak-boson and the
Goldstone boson as a criterion for sensitively probing the electroweak symmetry
breaking mechanism and develop a precise power counting rule for chiral
Lagrangian formulated electroweak theories. With these we semi-quatitatively
analyze the sensitivities to various effective operators related to
electrowaeak symmetry breaking via weak-boson scatterings at the CERN Large
Hadron Collider (LHC).


title: Physical Parameters and Renormalization of U(1)_a x U(1)_b Models

abstract:
  We analize the structure of models with unbroken and spontaneously broken
U(1)_a x U(1)_b gauge symmetry. We show that the quantum corrections to the 2N
gauge charges, with N = #fermions + #scalars, can be absorbed in the
redefinition of three independent gauge couplings (g_a,g_b and g_ab). We
establish the (one-loop) conditions on the matter cotent for g_ab= = 0 (a value
usually assumed in the literature) and we show that in the minimal extensions
of the Standard Model with an extra U(1) symmetry the choice g_ab = 0 is not
stable under radiative corrections induced by the standard Higgs fields.
Moreover, g_ab = 0 to all orders seems to require an exact symmetry. The
spontaneous breaking of the gauge symmetry induces further mixing between the
two gauge bosons and introduces a fourth independent physical parameter. A
consequence of our analysis is that the usual tree-level description with only
three physical parameters (i.e., two gauge couplings and one gauge boson mixing
angle) is not in general a justified zero order limit of the treatment
including radiative corrections.


abstract:
  The present CORE 2.1 (COmpendium of RElations, Version 2.1) contains various
formulas and relations used in the practical calculations in the Standard
Model. The properties of the Pauli, Dirac, Gell--Mann matrices, wave functions
of free fermions and gauge bosons are considered. We present the full
Lagrangian of the Standard Model and the corresponding Feynman rules. The
method of the evaluation of the Feynman (loop) integrals and calculations in
non-covariant gauges is considered. We discuss in brief the relativistic
kinematic and present a large number of the matrix elements of the various
processes in the Standard Model.


title: Embedded Vortices

abstract:
  We present a discussion of embedded vortices in general Yang-Mills theories.
The origin of a family structure of solutions is shown to be group theoretic in
nature and a procedure for its determination is developed. Vortex stability can
be quantified into three types: Abelian topological stability, non-Abelian
topological stability, and dynamical stability; we relate these to the family
structure of vortices, in particular discussing how Abelian topological and
dynamical stability are related. The formalism generally encompasses embedded
domain walls and embedded monopoles also.


abstract:
  Dilepton production from resonance scattering in hot hadronic matter is
studied. Including the widths of these resonances, which enhance the phase
space for dilepton production, we find that the production rate is
significantly increased if a resonance appears in the extended phase space. For
the reaction $\pi+\rho\to l^++l^-$, the finite $\rho$ meson width extends the
invariant mass below the $\omega$-meson mass, so a peak at the $\omega$ meson
mass is seen in the dilepton spectrum. Similarly, a $\rho$-meson peak appears
in the reaction $\rho+\rho\to l^++l^-$. On the other hand, the effect of
particle widths in the reaction $\pi+a_1\to l^++l^-$ is small since the
extended phase space does not include any resonance.


title: A $J^\pi = 0^-$ Resonance for $\pi NN \to \pi NN $ in the Skyrme Model

abstract:
  The scattering of pions on a dibaryon configuration is analyzed within the
$SU(2)$ Skyrme model. It is shown that this model leads to a low-lying
$(J^P,I)= (0^-,2)$ resonance. The possibility that this resonance corresponds
to one proposed recently in the context of double charge exchange pion
scattering on nuclei is discussed. Given the setup used in those experiments we
also show that a resonance with isospin assignment $I=0$ cannot be excited
according to the description presented here.


title:
A Determination of the CKM-angle $\alpha$ using Mixing-induced CP
  Violation in the Decays $B_d\to\pi^+\pi^-$ and $B_d\to K^0 \bar K^0$

abstract:
  We present a method of determining the CKM-angle $\alpha$ by performing
simultaneous measurements of the mixing-induced CP asymmetries of the decays
$B_d\to\pi^+\pi^-$ and $B_d\to K^0\bar K^0$. The accuracy of our approach is
limited by $SU(3)$-breaking effects originating from $\bar b\to \bar ds\bar s$
QCD-penguin diagrams. Using plausible power-counting arguments we show that
these uncertainties are expected to be of the same order as those arising
through electroweak penguins in the standard Gronau-London-method in which
$\alpha$ is extracted by means of isospin relations among $B\to\pi\pi$ decay
amplitudes. Therefore our approach, which does not involve the experimentally
difficult mode $B_d\to\pi^0\pi^0$ and is essentially unaffected by electroweak
penguins, may be an interesting alternative to determine $\alpha$.


title:
Supersymmetric QCD Corrections to the Charged Higgs Boson Decay of the
  Top Quark

abstract:
  The one-loop supersymmetric QCD quantum effects on the width of the
unconventional top quark decay mode $t\rightarrow H^{+}\, b$ are evaluated
within the MSSM. The study of this process is useful to hint at the
supersymmetric nature of the charged Higgs emerging from that decay. Remarkably
enough, recent calculations of supersymmetric corrections to $Z$-boson
observables have shown that the particular conditions by which the decay
$t\rightarrow H^{+}\, b$ becomes competitive with the standard decay
$t\rightarrow W^{+}\,b$ have a chance to be realized in nature. This further
motivates us to focus our attention on the dynamics of $t\rightarrow H^{+}\, b$
as an excellent laboratory to unravel Supersymmetry at the quantum level in
future experiments at Tevatron and at LHC.


title: Horizontal Symmetries for the Supersymmetric Flavor Problem

abstract:
  The heaviness of the third family fermions and the experimental absence of
large flavor violating processes suggest, in supersymmetric theories, that the
three families belong to a $2+1$ representation of a horizontal symmetry $G_H$.
In this framework, we discuss a class of models based on the group U(2) that
describe the fermion flavor structure and are compatible with an underlying
GUT. We study the phenomenology of these models and focus on two interesting
scenarios: In the first one, the first and second family scalars are assumed to
be heavier than the weak scale allowing for complex soft supersymmetry breaking
terms. In the second one, all the CP-violating phases are assumed to be small.
Both scenarios present a rich phenomenology in agreement with constraints from
flavor violating processes and electric dipole moments.


title: Higgs-photon associated production at $e\bar{e}$ colliders

abstract:
  We present complete analytical expressions for the amplitudes of the process
$e\bar{e}\rightarrow H\gamma$. The calculation is performed using nonlinear
gauges, which significantly simplifies both the actual analytical calculation
and the check of its gauge invariance. After comparing our results with a
previous numerical calculation, we extend the range of Higgs masses and center
of mass energies to those appropriate to LEP 200 and a future linear collider.


title: Addendum to the Test of CP Violation in Tau Decay

abstract:
  We discuss the test of CP and CPT violation in $\tau$ decay without using the
polarized electron beam by comparing partial fractions of $\tau^-$ and $\tau^+$
decay into channels with strong final state interactions. For example,
$\Gamma(\tau^-\rarrow \pi^-+\pi^0+\nu) \ne \Gamma(\tau^+\rarrow
\pi^++\pi^0+\nu)$ signifies violation of CP. The optimum energy to investigatge
CP violation in $\tau$ decay is discussed. We conclude that this energy is a
few MeV below $\psi(2s)$ in order to avoid the charm contribution and over
abundance of hadrons at the $\psi(2s)$ peak.


title: Locality of the Strange Sea in the Nucleon

abstract:
  We introduce the concept of ``locality" for the strange sea in the nucleon,
which measures proximity of the strange and anti-strange quarks in the momentum
and coordinate spaces. The CCFR data for the strange and anti-strange
distributions imply a ``local" strange sea in the momentum space, which is
unexpected in QCD and is at variance with the simple meson-cloud model where
the strangeness is generated from the virtual transition of the nucleon to a
hyperon plus a kaon. We present a simple model to interpret the CCFR data and
to correlate momentum and coordinate space locality, yielding an upper bound of
0.005 fm$^2$ on the strange radius. We also discuss significances of locality
for other charge-conjugation-odd observables.


title: Examples of Embedded Defects (in Particle Physics and Condensed Matter)

abstract:
  We present a series of examples designed to clarify the formalism of the
companion paper `Embedded Vortices'. After summarising this formalism in a
prescriptive sense, we run through several examples: firstly, deriving the
embedded defect spectrum for Weinberg-Salam theory, then discussing several
examples designed to illustrate facets of the formalism. We then calculate the
embedded defect spectrum for three physical Grand Unified Theories and conclude
with a discussion of vortices formed in the superfluid $^3$He-A phase
transition.


title: Systematic Study of Horizontal Gauge Theories

abstract:
  We analyze all the possible continuous horizontal gauge groups G_H in
relation with their possibility to explain m_b<<m_t. We assume that the only
effective fermionic degrees of freedom correspond to the known fermions but
allow the possibility of adding a right handed neutrino to each family. We
assume that the Higgs fields which generate masses for these fermions, trough
renormalizable Yukawa couplings, transform as an irreducible representation of
SU(3)_c\otimesSU(2)_L\otimesU(1)_Y\otimesG_H. Under these assumptions we find
two U(1)_H or U(1)_{H1}\otimesU(1)_{H2} models free of anomalies and able to
guarantee that only the top has a renormalizable mass-generating Yukawa
coupling.


title: Di-photon + Jet Event Structure

abstract:
  New distributions are presented which allow di-photon + jet events to be
clearly separated into three classes of events based on the $p_{T}$ of the
final state particles and their separation $R$ = $\sqrt{(\Delta y)^{2} +
(\Delta \phi)^{2}}$. The analysis used can easily be extended to the case of
di-jet + photon.


title:
Consequence of the Wigner Rotation: Perturbative QCD Analysis of the
  Pion Form Factor

abstract:
  We analyse the perturbative contributions from the higher helicity
($\lambda_{1}+\lambda_{1}=\pm 1$) components, which should be naturally
contained in the light-cone wave function for the pion as a consequence of the
Wigner rotation, in the QCD calculation of the pion form factor. It is pointed
out that the contributions may provide the other fraction needed to fit the
pion form factor data besides the perturbative contributions from the ordinary
helicity components evaluated using the factorization formula with the
asymptotic form of the distribution amplitude. We suggest a way to test the
higher helicity state contributions.


title: Photon Production from a Quark--Gluon Plasma

abstract:
  In-medium interactions of a particle in a hot plasma are considered in the
framework of thermal field theory. The formalism to calculate gauge invariant
rates for photon and dilepton production from the medium is given. In the
application to a QED plasma, astrophysical consequences are pointed out. The
photon production rate from strongly interacting quarks in the quark--gluon
plasma, which might be formed in ultrarelativistic heavy ion collisions, is
calculated in the previously unaccessible regime of photon energies of the
order of the plasma temperature. For temperatures below the chiral phase
transition, an effective field theory incorporating dynamical chiral symmetry
breaking is employed, and perturbative QCD at higher temperatures. A smooth
transition between both regions is obtained. The relevance to the soft photon
problem and to high energy heavy ion experiments is discussed.


title:
The classical sphaleron transition rate exists and is equal to
  $1.1(\alpha_w T)^4$

abstract:
  Results of a large scale numerical simulation show that the high temperature
Chern-Simons number diffusion rate in the electroweak theory has a classical
limit $\Gamma = \kappa (\alpha_w T)^4$, where $\kappa = 1.09\pm 0.04$ and
$\alpha_w$ is the weak fine structure constant.


title: Quantum Statistics and Parton Distributions

abstract:
  A novel approach to parton distributions parameterization in terms of quantum
statistical functions is here outlined. The description, already proposed in
previous publications, is here improved by adding to the statistical
distributions an unpolarized {\it liquid} component. This new contribution to
fermion partons is able to reproduce the expected low $x$ behaviour of
structure functions. The analysis provides a satisfactory description of
polarized and unpolarized deep inelastic data and shows a possible connection
between the Gottfried and Bjorken sum rules.


title: Low-energy expansion of the pion-nucleon Lagrangian

abstract:
  The renormalized pion-nucleon Lagrangian is calculated to O(p^3) in heavy
baryon chiral perturbation theory. By suitably chosen transformations of the
nucleon field, the Lagrangian is brought to a standard form.


title:
Meson Cloud of the Nucleon in Polarized Semi-Inclusive Deep-Inelastic
  Scattering

abstract:
  We investigate the possibility of identifying an explicit pionic component of
the nucleon through measurements of polarized $\Delta^{++}$ baryon fragments
produced in deep-inelastic leptoproduction off polarized protons, which may
help to identify the physical mechanism responsible for the breaking of the
Gottfried sum rule. The pion-exchange model predicts highly correlated
polarizations of the $\Delta^{++}$ and target proton, in marked contrast with
the competing diquark fragmentation process. Measurement of asymmetries in
polarized $\Lambda$ production may also reveal the presence of a kaon cloud in
the nucleon.


title: Magnetic Confinement and Screening Masses

abstract:
  Confined and deconfined phases are defined through nonperturbative
correlators and nonperturbative background perturbation theory is used to
compute the critical temperature $T_c$ and spatial string tension. Taking
evolution along one of the spatial axes the set of Hamiltonians $H(n_1,n_2)$
with different Matsubara frequencies is obtained.
  Meson and glueball screening masses and wave functions are computed for
$H(0,0)$ and compared with available lattice data.


title: $\gamma^*p\to\Delta$ Form Factors in QCD

abstract:
  We use local quark-hadron duality to estimate the purely nonperturbative soft
contribution to the $\gamma^* p \to \Delta$ form factors. Our results are in
agreement with existing experimental data. We predict that the ratio
$G_E^*(Q^2)/G_M^*(Q^2)$ is small for all accessible $Q^2$, in contrast to the
pQCD expectations that $G_E^*(Q^2) \to -G_M^*(Q^2)$.