title: Model-Independent Predictions of Big Bang Nucleosynthesis

abstract:
  We derive constraints from standard (with $N_\nu = 3$) BBN arising solely
from two cosmologically produced nuclides, \he4 and \li7, from which the
extrapolation to primordial abundances is straightforward. The abundances of D
and \he3 are at present only inferred from their solar and local interstellar
medium values using models of galactic chemical evolution. However, our
knowledge of chemical evolution suffers from large uncertainties, and so it is
of use to take an approach which minimizes the reliance on chemical evolution
in determining the consistency of BBN. Using only the data on \he4 and \li7,
and reasonable estimates of possible systematic errors in their abundance
determinations, concordance is found if the baryon-to-photon ratio lies in the
range $1.4 < 10^{10} \eta < 3.8$ (95\% CL). The \he4 and \li7 abundances are
also used to predict the primordial abundances D and \he3, which provides an
initial condition for their chemical evolution.


title: $b\to s \gamma$ Decay in the Two Higgs Doublet Model

abstract:
  QCD corrections to $b \to s \gamma$ decay in the two Higgs doublet model are
calculated from the energy scale of top quark to that of bottom. The
constraints on the two Higgs doublet model from the new experimental bounds of
$b\to s\gamma$ by CLEO and the latest top quark mass by CDF and D0 are
reanalyzed. It 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: Non-Minimal Supersymmetric Higgs Bosons at LEP2

abstract:
  We discuss the discovery reach of LEP2 for the Higgs sector of a general
extension of the MSSM including a single gauge singlet field. This change
introduces a new quartic Higgs boson self-coupling which can increase the
masses of the CP-even states, and also allows mixing between singlet and
non-singlet states which can reduce the couplings of the mass eigenstates to
the $Z$. The lightest CP-even Higgs boson is bounded by a parameter $\Lambda$
which takes a maximum value $\Lambda_{max}\approx 136-146$ GeV for top mass
$150-195$ GeV. We generalise the discussion of the bound to include the entire
CP-even spectrum and show how experiment may exclude values of $\Lambda$
smaller than some $\Lambda_{min}$. CP-even Higgs boson searches at LEP2 will be
able to exclude $\Lambda_{min}\approx 81-105$ GeV, depending on the machine
parameters. We also present exclusion plots in the $m_A-\tan\beta$ plane, based
on an analysis of CP-even, CP-odd and charged Higgs production processes at
LEP2.


title:
Next-to-Leading Order Radiative Parton Model Analysis of Polarized Deep
  Inelastic Scattering

abstract:
  A next-to-leading order QCD analysis of spin asymmetries and structure
functions in polarized deep inelastic lepton nucleon scattering is presented
within the framework of the radiative parton model. A consistent NLO
formulation of the $Q^2$-evolution of polarized parton distributions yields two
sets of plausible NLO spin dependent parton distributions in the conventional
$\overline{\rm{MS}}$ factorization scheme. They respect the fundamental
positivity constraints down to the low resolution scale
$Q^2=\mu^2_{NLO}=0.34\,{\rm{GeV}}^2$. The $Q^2$-dependence of the spin
asymmetries $A_1^{p,n,d}(x,Q^2)$ is similar to the leading-order (LO) one in
the range $1\le Q^2\le 20\,{\rm{GeV}}^2$ and is shown to be non-negligible for
$x$-values relevant for the analysis of the present data and possibly
forthcoming data at HERA.


title: Mass relation of rho and a_{1} mesons

abstract:
  A mass relation of rho and a_[1} mesons has been obtained from Weinberg's
first sum rule and KSFR sum rule.


title: Potential for Discoveries in Charm Meson Physics

abstract:
  The possibility of using charm meson physics to test the Standard Model (SM)
is reviewed. In the case of $D^0-\bar{D}^0$ mixing, the SM contributions are
carefully considered and the existence of a window for the observation of new
physics is discussed. Some examples of extensions of the SM giving large mixing
signals are presented. Finally, some distinctive aspects of CP violation and
rare decays in charm mesons are discussed.


title:
Small scale structure predictions from discrete symmetry breaking -
  early quasar formation

abstract:
  We discuss the local density fluctuations which arise due to the topological
defects that appear after the phase transition of light pseudo-Goldstone
bosons. It has been found that in a post-inflationary universe the fluctuations
of these defects at large scales may have led to galaxy formation, while being
consistent with the measurements of the cosmic microwave background radiation.
Here we show that, at the local level, the fluctuations may be sufficiently
large to lead to the production of smaller structures (ie quasars) with the
observed distribution, which peaks at $z=2$ and drops rapidly for higher
redshifts. Moreover it may be possible that a limited number of quasars are
produced at redshifts of order 10, much earlier than what hot and cold dark
matter scenarios predict. Although in this letter we work in the parameter
space which is optimal for the generation of large scale structure as well,
these features are generic for a wide class of domain wall models.


title:
Perturbative QCD Calculations of Total Cross Sections and Decay Widths
  in Hard Inclusive Processes

abstract:
  A summary of the current understanding of methods of analytical higher order
perturbative computations of total cross sections and decay widths in Quantum
Chromodynamics is presented. As examples, the total cross section in electron
positron annihilation, the hadronic decay rates of the tau lepton and Higgs
boson up to O(\alpha_s^2) and O(\alpha_s^3) are considered. The evaluation of
the four-loop QED \beta - function at an intermediate step of the calculation
is briefly described. The problem of renormalization group ambiguity of
perturbative results is considered and some of the existing prescriptions are
discussed. The problem of estimation of theoretical uncertainty in perturbative
calculations is briefly discussed.


title: Nonperturbative Condensates in the Electroweak Phase-Transition

abstract:
  We discuss the electroweak phase-transition in the early universe, using
non-perturbative flow equations for a computation of the free energy. For a
scalar mass above $\sim 70$ GeV, high-temperature perturbation theory cannot
describe this transition reliably. This is due to the dominance of
three-dimensional physics at high temperatures which implies that the effective
gauge coupling grows strong in the symmetric phase. We give an order of
magnitude-estimate of nonperturbative effects in reasonable agreement with
recent results from electroweak lattice simulations.
  (Talk given by C. Wetterich at the 3rd Colloque Cosmologie, Paris, June 7-9,
1995, to appear in the proceedings)


title: Medium Modifications of the Rho Meson at CERN/SPS Energies

abstract:
  Rho meson propagation in hot hadronic matter is studied in a model with
coupling to $\pi\pi$ states. Medium modifications are induced by a change of
the pion dispersion relation through collisions with nucleons and $\Delta's$ in
the fireball. Maintaining gauge invariance dilepton production is calculated
and compared to the recent data of the CERES collaboration in central S+Au
collisions at 200 GeV/u. The observed enhancement of the rate below the rho
meson mass can be largely accounted for.


title:
Baryon masses and pion-nucleon $\sigma$-term to second order in the
  quark masses

abstract:
  We analyze the octet baryon masses and the pion--nucleon $\sigma$--term in
the framework of heavy baryon chiral perturbation theory. In contrast to
previous investigations, we include {\it all} terms up-to-and-including
quadratic order in the light quark masses. The pertinent low--energy constants
are fixed from resonance exchange. This leaves as the only free parameter the
baryon mass in the chiral limit, $\krig{m}$. We find $\krig{m} = 749 \pm
125$~MeV together with $\sigma_{\pi N} (0) = 48 \pm 10$ ~MeV. We discuss
various implications of these results.


title: Effects of R Parity Breaking in the Higgs Sector

abstract:
  We discuss possible manifestations of R parity breaking in the Higgs sector.
We illustrate this with three examples: high-energy mono-photon production at
LEP, calculation of limits on associated production of invisibly decaying Higgs
bosons and discussion of non-standard scalar decays in the MSSM with broken R
parity.


title: $\rho\to 4\pi$ in chirally symmetric models

abstract:
  The decays $\rho^0\to 2\pi^+2\pi^-$ and $\rho^0\to 2\pi^0\pi^+\pi^-$ are
studied using various effective Lagrangians for $\pi$ and $\rho$ (and in some
cases $a_1$) mesons, all of which respect the approximate chiral symmetry of
the strong interaction. Partial widths of the order of 1 keV or less are found
in all cases. These are an order of magnitude smaller than recent predictions
based on non-chiral models.


title: The Effect of Top Quark Polarization at Hadronic Colliders

abstract:
  We derive a simple analytic expression for q \bar{q}, g g -> t \bar{t} -> b
W^+ \bar{b} W^- -> b \bar{l} \nu_l \bar{b} l' \bar{\nu_{l'}} for on shell
intermediate states with the interference effects due to the polarizations of
the t and \bar{t}. We then investigate how this effect may be measured at
Tevatron or other hadronic colliders.


title: Soft Gluon Resummation

abstract:
  I discuss some of the basic techniques and results of soft gluon resummation,
and their applications to scattering at collider energies.


title: Phenomenological Evidence for the Gluon Content of $\eta$ and $\eta'$

abstract:
  We discuss the effect of $\eta$--$\eta'$ mixing and of axial current
anomalies on various decay processes. We describe the 2$\gamma$ decays of
$\eta$ and $\eta'$, the radiative decays of low-lying vector mesons as well as
the decays $\eta\to 3\pi$, $J/\psi\to\eta\gamma$ and $J/\psi\to\eta'\gamma$ in
one unified framework, in which they are related to the electromagnetic and
strong axial current anomalies, respectively. We also discuss briefly the
enhancement of $\eta'$ in $D_s$ decays and suggest a possible relation to
gluon-mediated processes. The importance of the decays of the glueball
candidates $f_0(1500)$ and $ f_0(1590)$ into $\eta \eta'$ channels is also
stressed.


title: What Thermodynamics tells about QCD Plasma near Phase Transition

abstract:
  Due to a rapid change of the entropy density $s(T)$ across the critical
temperature $T_c$ of the QCD phase transition, the pressure $P(T)$ and the
energy density $e(T)$ above $T_c$ generally deviate from their Stefan-Boltzmann
values. We shall demonstrate this both analytically and numerically for a
general class of $s(T)$ consistent with thermodynamical constraints and make a
qualitative comparison of the result with the lattice QCD data. Quantities
related to $ds(T)/dT$ such as the specific heat and sound velocity are also
discussed.


title: Resolved Photon and Rapidity Gap in Jet Events

abstract:
  We study the production of jet events containing large rapidity gaps in
particle colliders due to the resolved photon mechanism. In particular, we
analize these events at DESY HERA and future $e^+e^-$ linear colliders,
including the possibility of $\gamma\gamma$ laser backscattering beams. These
events allow the study of the perturbative pomeron in environments
complementary to the hadron-hadron colliders, and also provide insight into the
survival probability of the rapidity gaps involving photon initial state.


title:
Experimental Implications of Large CP Violation and Final State
  Interactions in the Search for $D^0\bar{D^0}$ Mixing

abstract:
  We discuss the implications of CP violation as well as final state
interaction phases in the experimental search for $D^0-\bar{D}^0$ mixing. At
the present level of sensitivity, these are not yet a significant systematic
experimental limitation.


title: Pseudo-Goldstone Bosons in Technicolor Models and the Phenomenology

abstract:
  In this report we present a review of recent developments in the TC/ETC
theories, concentrating on the theoretical estimations and the phenomenological
analysis about the Non-Oblique corrections on the $Zb\overline{b}$ vertex from
ETC dynamics and Pseudo-Goldstone Bosons. The relevant studies about the vertex
corrections on other processes from the PGBs were also considered.


title: On the mass splitting between axial and vector heavy-light mesons

abstract:
  Mass splitting between axial and vector $\bar{Q}q$ mesons is considered
within the standard QCD sum rules. In agreement with the first experimental
data on the $B_1$ meson ($J^P =1^{+}$) we find that the splitting for B is
about the same as for D and show that $1/m_Q$ corrections to the meson masses
are small.


title: CP violation in multi-Higgs supersymmetric models

abstract:
  We consider supersymmetric extensions of the standard model with two pairs of
Higgs doublets. We study the possibility of spontaneous $CP$ violation in these
scenarios and present a model where the origin of $CP$ violation is soft, with
all the complex phases in the Lagrangian derived from complex masses and vacuum
expectation values (VEVs) of the Higgs fields. The main ingredient of the model
is an approximate global symmetry, which determines the order of magnitude of
Yukawa couplings and scalar VEVs. We assume that the terms violating this
symmetry are suppressed by powers of the small parameter
$\epsilon_{PQ}=O(m_b/m_t)$. The tree-level flavor changing interactions are
small due to a combination of this global symmetry and a flavor symmetry, but
they can be the dominant source of $CP$ violation. All $CP$-violating effects
occur at order $\epsilon_{PQ}^2$ as the result of exchange of {\it
almost}-decoupled extra Higgs bosons and/or through the usual mechanisms with
an {\it almost}-real CKM matrix. On dimensional grounds, the model gives
$\epsilon_K\approx \epsilon_{PQ}^2$ and predicts for the neutron electric
dipole moment (and possibly also for $\epsilon'_K$) a suppression of order
$\epsilon_{PQ}^2$ with respect to the values obtained in standard and minimal
supersymmetric scenarios. The predicted $CP$ asymmetries in $B$ decays are
generically too small to be seen in the near future. The mass of the lightest
neutral scalar, the strong $CP$ problem, and possible contributions to the $Z$
decay into $b$ quarks (the $R_b$ puzzle) are also briefly addressed in the
framework of this model.


title: Tests for Tau's Charged-Current Structure

abstract:
  The Lorentz structure of the tau lepton's charged-current can almost be
completely determined by use of stage-two spin-correlation functions for the
$\{\rho ^{-},\rho ^{+}\}$and $\{a_1^{-},a_1^{+}\}$ decay modes. It is possible
to test for a ``$(V-A)$ $ + $ something'' structure in the
${J^{Charged}}_{Lepton}$ current, so as to bound the scales $\Lambda$ for ``new
physics" such as arising from tau weak magnetism, weak electricity, and/or
2nd-class currents. In practice, only limited information can be obtained from
the $\tau \rightarrow \pi \nu$ modes.


title: A General Treatment of Tau Semi-Leptonic Decays

abstract:
  The most general Lorentz invariant spin-correlation functions for $\tau
^{-}\rightarrow \rho ^{-}\nu ,a_1^{-}\nu ,K^{*-}\nu , \pi ^{-}\nu ,K^{-}\nu $
are expressed in terms of eight semi-leptonic parameters. They are physically
defined in terms of tau-decay partial-width-intensities for
polarized-final-states. The parameters are also expressed in terms of a
``$(V-A)\ +\ $additional chiral coupling'' structure in the
${J^{Charged}}_{Lepton}$ current, so as to bound the scales $\Lambda $\ for
``new physics'' such as arising from leptonic CP violation, tau weak magnetism,
weak electricity, and/or second-class currents. The two tests for leptonic CP
violation in $\tau \rightarrow \rho \nu \ $ decay are generalized to $\tau
\rightarrow a_1\nu \ $ decay and to two additional tests if there are $\nu _R\
$ and $\bar \nu _L\ $ couplings.


title:
General Classical Solutions of Nonlinear $\sigma$-Model and Pion Charge
  Distribution of Disoriented Chiral Condensate

abstract:
  We obtain the general analytic solutions of the nonlinear $\sigma$-model in
$3+1$ dimensions as the candidates for the disoriented chiral condensate (DCC).
The nonuniformly isospin-orientated solutions are shown to be related to the
uniformly oriented ones through the chiral (axial) rotations. We discuss the
pion charge distribution arising from these solutions. The distribution
$dP/df=1/(2\sqrt{f})$ holds for the uniform solutions in general and the
nonuniform solutions in the $1+1$ boost invariant case. For the nonuniform
solution in $1+1$ without a boost-invariance and in higher dimensions, the
distribution does not hold in the integrated form. However, it is applicable to
the pions selected from a small segment in the momentum phase space. We suggest
that the nonuniform DCC's may correspond to the mini-Centauro events.


title: Democracy of Families and Neutrino Mass Matrix

abstract:
  On the basis of a seesaw-type mass matrix model for quarks and leptons, $M_f
\simeq m_L M_F^{-1} m_R$, where $m_L\propto m_R$ are universal for $f=u,d,\nu$
and $e$ (up-quark-, down-quark-, neutrino- and charged lepton-sectors), and
$M_F$ is given by $M_F=K ({\bf 1} + 3 b_f X)$ ({\bf 1} is a $3\times 3$ unit
matrix, $X$ is a democratic-type matrix and $b_f$ is a complex parameter which
depends on $f$, neutrino mass spectrum and mixings are discussed. The model can
provide an explanation why $m_t \gg m_b$, while $m_u\sim m_d$ by taking
$b_u=-1/3$, at which the detarminant of $M_F$ becomes zero. At $b_\nu=-1/2$,
the model can provide a large $\nu_\mu$-$\nu_\tau$ mixing, $\sin^2
2\theta_{23}\simeq 1$, with $m_{\nu 1} \ll m_{\nu 2} \simeq m_{\nu 3}$, which
is favorable to the atmospheric and solar neutrino data.


title: Effect of the Flavor Changing Neutral Current on Rare $B$ decays

abstract:
  We study the effect of the FCNC on rare $B$ decays in the beyond standard
model with vector like singlet quarks. It has been shown that $b \rightarrow s
\gamma $ does not receive sizable contribution compared with that of the
standard model while $b \rightarrow d \gamma $, $b \rightarrow s(d) l^+ l^-$,
can be changed from the predictions of the standard model.


title:
Bogoliubov condensation of gluons and spontaneous gauge symmetry
  breaking in QCD

abstract:
  The problem of the gluonic quasiparticle excitations in QCD is considered
under the aspect of the condensation of gluon pairs in the ''squeezed'' vacuum.
The present approach is a field theoretical generalization of the Bogoliubov
model which successfully reproduced the Landau spectrum in the microscopic
theory of superfluidity. We construct a gauge invariant QCD Hamiltonian by
formally solving the Gauss equation such that the physical variables are
separated by a non-Abelian projection operator, instead of fixing a gauge. By
using Dirac quantization we show that the Bogoliubov condensation of gluon
pairs destroys this projection operator, and the spontaneous appearance of a
gluon mass is accompanied by a longitudinal component for the gluon field in
correspondence with the relativistic covariance. Gauge symmetry is broken
spontaneously since the gauge invariance of the Hamiltonian is not shared by
the vacuum. The squeezed vacuum in the present model is characterized by one
free parameter related to the contraction of a pair of zero momentum gluon
fields which is fixed from the difference of the $\eta'$ and the $\eta$ - meson
masses ($ U(1)$-problem) and results in a value for the gluon condensate which
is in good agreement with the value obtained by Shifman, Vainshtein and
Zakharov.


title: The Time Surface Term in Quantum Gravity

abstract:
  The role of the time surface term in the ADM Hamiltonian formulation of
general relativity is investigated. We show that the variable contained in the
time surface term (the scale factor) plays the role of a time-like variable.
The conjugated variable represents the energy density in the reduced phase
space, where the Schr\"odinger like equation for a wave function is derived.
The contribution from the surface term to the phase of the wave function allows
us to define {\bf the phase time of the quantum Universe} so that it coincides
with {\bf the proper time as an invariant interval} for the classical dust
filled Universe. The quantum scenario of the evolution of the Universe filled
in by the Weinberg-Salam fields is considered. The wave function of the early
Universe as the functional from the Higgs fields and scale factor realizes the
unitary irreducible representation of the SO(4,1) group. The elementary
particle masses are determined by the angles of the scale--scalar field mixing.


title:
Signature for Color-Octet Production of $J/\psi$ in $e^+ e^-$
  Annihilation

abstract:
  The inclusive cross section for the production of $J/\psi$ in $e^+ e^-$
annihilation is studied using a recently developed factorization formalism. In
addition to the conventional color-singlet contribution, we include
contributions from $c \bar c$ pairs that are produced at short distances in
color-octet states. The color-octet contributions are suppressed by the smaller
probability for the color-octet $c \bar c$ pair to evolve into a state that
includes a $\psi$, but they may dominate near the upper endpoint of the $\psi$
energy spectrum. The signature for the color-octet contribution is a dramatic
change in the angular distribution of the $\psi$ near the endpoint.


title:
Relations between Spin Structure Functions and Quark Mass Corrections to
  Bjorken Sum Rule

abstract:
  The power correction, surviving the zero quark mass limit and found earlier
to restore the validity of Burkhardt-Cottingham sum rule, provides the
contribution to the Bjorken sum rule as well. The leading perturbative
correction to the Bjorken sum rule is increased by the factor 4/3 for light
quarks and 5/3 for heavy quarks. The resulting value for the Bjorken sum rule
for light quarks is in excellent agreement with the most precise SLAC data. The
same correction should appear in the case of the Gross-Llewellyn Smith sum
rule. It completely removes the observed deficit of this sum rule within the
experimental errors.


title: Shapes of Cosmic Strings and Baryon Number Violation

abstract:
  The relation between shapes of cosmic string and baryon number violation is
investigated. If there exist fermionic zero modes on the string, using
bosonization technique, it is possible to obtain the effective action which
describes the fermion coupled to the arbitrarily shaped cosmic string. The
relation between baryon number and the sum of the writhing number and linking
number of the cosmic strings is rederived. Baryons are created on the strings
as the shapes of the cosmic strings change. Furthermore we discuss implications
of this baryon number violating process to baryogenesis.


title: Nonoblique Effects and Weak-Isospin Breaking from Extended Technicolor

abstract:
  Several aspects of the flavor-diagonal extended technicolor (ETC) gauge boson
are reviewed. Among them are an increase of $R_b$ that could explain the LEP
$R_b$ excess, a sizable, positive correction to the $\tau$ asymmetry parameter
$A_{\tau}$, and a contribution to the weak-isospin breaking $\rho$ parameter
that is just barely acceptable by present data.


title: Bern-Kosower Rule for Scalar QED

abstract:
  We derive a full Bern-Kosower-type rule for scalar QED starting from quantum
field theory: we derive a set of rules for calculating $S$-matrix elements for
any processes at any order of the coupling constant. Gauge-invariant set of
diagrams in general is first written in the worldline path-integral expression.
Then we integrate over $x(\tau)$, and the resulting expression is given in
terms of correlation function on the worldline $\left< x(\tau) x(\tau')
\right>$. Simple rules to decompose the correlation function into basic
elements are obtained. Gauge transformation known as integration by parts
technique can be used to reduce the number of independent terms before
integration over proper-time variables. The surface terms can be omitted
provided the external scalars are on-shell. Also, we clarify correspondence to
the conventional Feynman rule, which enabled us to avoid any ambiguity coming
from the infinite dimensionality of the path-integral approach.


title: Particle Production and Dissipative Cosmic Field

abstract:
  Large amplitude oscillation of cosmic field that may occur right after
inflation and in the decay process of weakly interacting fields gives rise to
violent particle production via the parametric resonance. In the large
amplitude limit the problem of back reaction against the field oscillation is
solved and the energy spectrum of created particles is determined in a
semi-classical approximation. For large enough coupling or large enough
amplitude the resulting energy spectrum is broadly distributed, implying larger
production of high energy particles than what a simple estimate of the
reheating temperature due to the Born formula would suggest.


title:
Generic Rules for High Temperature Dimensional Reduction and Their
  Application to the Standard Model

abstract:
  We formulate the rules for dimensional reduction of a generic finite
temperature gauge theory to a simpler three-dimensional effective bosonic
theory in terms of a matching of Green's functions in the full and the
effective theory, and present a computation of a generic set of 1- and 2-loop
graphs needed for the application of these rules. As a concrete application we
determine the explicit mapping of the physical parameters of the standard
electroweak theory to a three-dimensional SU(2)xU(1) gauge-Higgs theory. We
argue that this three-dimensional theory has a universal character and appears
as an effective theory for many extensions of the Standard Model.


title:
Constraints on Masses of Charged PGBs in Technicolor Model from Decay $
  b \to s \gamma $

abstract:
  In this paper we calculate the contributions to the branching ratio of $B\to
X_s \gamma$ from the charged Pseudo-Goldstone bosons appeared in one generation
Technicolor model. The current $CLEO$ experimental results can eliminate large
part of the parameter space in the $m(P^\pm) - m(P_8^\pm)$ plane, and
specifically, one can put a strong lower bound on the masses of color octet
charged PGBs $P_8^\pm$: $m(P^{\pm}_8) > 400\;GeV$ at $90\%C.L$ for free
$m(P^{\pm})$.


title: Radiative corrections to $e \gamma$ scattering

abstract:
  We investigate the effects of photon radiation on deep-inelastic $\re\gamma$
scattering. Depending on the set of variables chosen, we find appreciable
effects in the kinematic region accessible at LEP2. Convenient analytic results
for $O(\alpha)$ corrected differential cross sections are presented.


title:
Analysis of Two-Body Decays of Charmed Baryons Using the Quark-Diagram
  Scheme

abstract:
  We give a general formulation of the quark-diagram scheme for the nonleptonic
weak decays of baryons. We apply it to all the decays of the antitriplet and
sextet charmed baryons and express their decay amplitudes in terms of the
quark-diagram amplitudes. We have also given parametrizations for the effects
of final-state interactions. For SU(3) violation effects, we only parametrize
those in the horizontal $W$-loop quark diagrams whose contributions are solely
due to SU(3)-violation effects. In the absence of all these effects, there are
many relations among various decay modes. Some of the relations are valid even
in the presence of final-state interactions when each decay amplitude in the
relation contains only a single phase shift. All these relations provide useful
frameworks to compare with future experiments and to find out the effects of
final-state interactions and SU(3) symmetry violations.


title: An Extension to Models for Cosmic String Formation

abstract:
  The canonical Monte-Carlo algorithm for simulating the production of
string-like topological defects at a phase transition is extended by
introducing a distribution of domain sizes. A strong correlation is found
between the fraction in the form of `infinite' string and the variance of the
volume of the regions of constant phase.


title:
Expulsion of Magnetic Flux Lines from the Growing Superconducting Core
  of a Magnetized Quark Star

abstract:
  The expulsion of magnetic flux lines from a growing superconducting core of a
quark star has been investigated. The idea of impurity diffusion in molten
alloys and an identical mechanism of baryon number transport from hot
quark-gluon-plasma phase to hadronic phase during quark-hadron phase transition
in the early universe, micro-second after big bang has been used. The
possibility of Mullins-Sekerka normal-superconducting interface instability has
also been studied.


title: Flavour Equilibration in Quark-Gluon Plasma

abstract:
  Within the framework of a dynamical and physically transparent model
developed earlier, we study the time evolution of various quark flavours in the
baryon-free region in ultrarelativistic heavy ion collisions. We show that even
under optimistic conditions, the quark-gluon system fails to achieve chemical
equilibrium.


title: Soft Colour Interactions as the Origin of Rapidity Gaps in DIS

abstract:
  We introduce soft colour interactions as a novel mechanism to understand the
observed events with large rapidity gaps in $ep$ collisions at HERA. Colour
exchanges between produced partons and colour-charges in the proton remnant
modifies the colour structure for hadronization, such that colour singlet
systems may appear well separated in rapidity. Our explicit model show
characteristics of diffractive scattering, although no explicit pomeron
dynamics have been introduced, and for non-gap events an increased forward
energy flow gives agreement with data.


title:
On the measurability of the structure function $g_1(X,Q^2)$ in $ep$
  collisions at HERA

abstract:
  The possibility is investigated to measure the polarized structure function
$g_1(x,Q^2)$ in the collider mode of HERA operating with a polarized lepton and
proton beam. The $x$ dependence of $g_1$ can be measured at a statistical
precision of $\sim 20\%~{\rm to}~80\%$ in the range $0.0005 < x < 0.5$
correlated to virtualities $15 < \langle Q^2 \rangle < 3500 \GeV^2$ at beam
polarizations $\lambda_p \sim \lambda_e = 0.8$ and ${\cal L}_{int} = 60
\PB^{-1}$. At a low energy option, $E_p = 300 \GeV$, the statistical accuracy
improves to values of $\sim 15\%~{\rm to}~50\%$ in the range $10^{-3} < x <
0.5$ and $10 < Q^2 < 800 \GeV^2$.


title:
Pion-proton scattering and isospin breaking in the
  $\Delta^0-\Delta^{++}$ system

abstract:
  We determine the mass and width of the $\Delta^{++}\ (\Delta^0)$ resonance
from data on $\pi^+ p\ (\pi^- p)$ scattering both, in the pole of the
$S$-matrix and conventional Breit-Wigner approaches to the scattering
amplitude. We provide a simple formula that relates the two definitions for the
parameters of the $\Delta$. Isospin symmetry breaking in the $\d0-\dm$ system
depends on the definition of the resonant properties: we find $M_0-M_{++} =
0.40 \pm 0.57\ {\rm MeV},\ \Gamma_0 -\Gamma_{++} = 6.89 \pm 0.95\ {\rm MeV}$ in
the pole approach while $\wt{M}_0-\wt{M}_{++} = 2.25 \pm 0.68\ {\rm MeV},\
\wt{\Gamma}_0 - \wt{\Gamma}_{++} = 8.45 \pm 1.11\ {\rm MeV}$ in the
conventional approach.


title: CP Violation: A Theoretical Review

abstract:
  This review of CP violation focuses on the status of the subject and its
likely future development through experiments in the Kaon system and with
B-decays. Although present observations of CP violation are perfectly
consistent with the CKM model, we discuss the theoretical and experimental
difficulties which must be faced to establish this conclusively. In so doing,
theoretical predictions and experimental prospects for detecting $\Delta S=1$
CP violation through measurements of $\epsilon^\prime/\epsilon$ and of rare K
decays are reviewed. The crucial role that B CP-violating experiments will play
in elucidating this issue is emphasized . The importance of looking for
evidence for non-CKM CP-violating phases, through a search for a non-vanishing
transverse muon polarization in $K_{\mu 3}$ decays, is also stressed.


title: S-Matrix Approach to the $Z$ Line Shape

abstract:
  We analyze the $Z$ line shape assuming the existence of an analytic, unitary
S-matrix. As an example, from hadron production at LEP we determine
$M_{Z}=91.134 \pm 0.020 \pm 0.020 \: ({\rm LEP})$ GeV, $\Gamma_{Z}=2.506 \pm
0.018$ GeV. This is in accordance with earlier results after performing a shift
of the $Z$ mass value of about $\frac{1}{2}\Gamma_Z^2/M_Z = 34$ MeV. The cross
section and related observables may be described by a small number of
additional degrees of freedom without relying on a specific field-theoretic
model.


title: PYTHIA 5.7 and JETSET 7.4 Physics and Manual

abstract:
  This is the latest edition of the physics description and manual of the
PYTHIA and JETSET programs for event generation in High Energy Physics.


title: The Status of Supersymmetry

abstract:
  Supersymmetry searches are about to enter an important new era. With LEP 200
and the Main Injector, they will, for the first time, begin to probe
significant regions of the supersymmetric parameter space. There is a real
chance that supersymmetry might indeed be found before the advent of the LHC.


title: On the Corrections to Dashen's Theorem

abstract:
  The electromagnetic corrections to the masses of the pseudoscalar mesons
$\pi$ and $K$ are considered. We calculate in chiral perturbation theory the
contributions which arise from resonances within a photon loop at order $O(e^2
m_q)$. Within this approach we find rather moderate deviations to Dashen's
theorem.


title: Remarks on the Coulomb and Covariant Gauges in Finite Temperature QED

abstract:
  We compare the use of the Coulomb gauge in finite temperature QED with a
recently proposed prescription for covariant gauges, in which only the
transverse photon degrees of freedom are thermalized. Using the Landau rule as
a guide, we clarify the relation between the retarded electron self-energy and
the elements of the self-energy matrix in the real-time formulation of . The
general results are illustrated by means of the one-loop expressions for the
electron self-energy in a QED plasma.


title: Membranes in the two-Higgs standard model

abstract:
  We present some non-topological static wall solutions in two-Higgs extensions
of the standard model. They are classically stable in a large region of
parameter space, compatible with perturbative unitarity and with present
phenomenological bounds.


title: Photoproduction of the Etas near Threshold

abstract:
  We extract a parameter $\xi$, a characteristic product of the strong and
electromagnetic amplitudes for the N^*(1535), to be (2.20+-0.15) in unit of
10^(-4)MeV^(-1) from the new data on photoproduction of etas off proton.


title: Leptoquark Production in Electron-Photon Scattering

abstract:
  We perform a model independent analysis of the production of scalar and
vector leptoquarks in the $e^-\gamma$ mode of a linear collider of the next
generation. Since these leptoquarks are produced singly, higher masses can be
probed than in other collider modes, like $e^+e^-$ scattering. We discuss the
discovery potential and show how polarization and angular distributions can be
used to distinguish between the different types of leptoquarks.


title: Mesonic Corrections to the Shape of Quark Distributions

abstract:
  We compute the full x - dependence of the proton and neutron spin structure
functions in the MIT bag model, including the effect of gluon exchange and the
meson cloud. Impressive agreement is found for x larger than 0.1, where
polarised gluons are not expected to play a significant role.


title:
Transverse Polarization of Top Quarks Produced in e+e- Annihilation at
  O(alpha_s)

abstract:
  We present the results of an O(alpha_s) calculation of the transverse
polarization of top quarks produced in e+e- annihilation. In a first step we
determine the transverse polarization of the top with regard to the hadron
plane spanned by the (q,bar q,g) system. We then rotate the transverse
components of the polarization to the lepton plane spanned by the (q,e+,e-)
system. After azimuthal averaging we determine the three remaining inclusive
transversely polarized structure functions. Together with the one-loop and Born
term contributions they determine the sin(theta) and sin(2*theta) beam-quark
polar angle dependence of the transverse polarization. We present analytic and
numerical results for the polarized structure functions and the polar angle
dependence of the transverse polarization. We briefly comment on the transverse
polarization of bottom quarks produced in e+e- annihilation.


title: Factorization Method in the Spontaneously Broken Gauge Theories

abstract:
  We consider the factorization method in the spontaneously broken gauge
theories such as the electroweak theory. Using the of\/f-shell $W$-boson
density matrix formalism we demonstrate that the factorization conditions are
completely under control. The main point of this paper is the presence of the
"interference" or "crossed" terms in $WW$--scattering process which exhibits
itself in the dependence on the relative azimuthal angle between two scattering
planes. To illustrate our general consideration we use well-known example --- a
single Higgs boson production. The origine of the quantitative failure of the
$WW$--ef\/fective method, as originally propossed, is given and it is shown how
to use it correctly.


title: Estimating Diffractive Higgs Boson Production at LHC from HERA Data

abstract:
  Using a recently proposed factorization hypothesis for semi-inclusive hard
processes in QCD, one can study, in principle, the diffractive production of
the Standard Model Higgs boson at LHC using only, as input, $ep$ diffractive
hard-processes data of the type recently collected and analyzed by the H1 and
ZEUS collaborations at HERA. While waiting for a more precise and complete set
of data, we combine here the existing data with a simple Pomeron-exchange
picture and find a large spread in the Higgs boson production cross section,
depending on the input parametrization of the Pomeron's parton content. In
particular, if the Pomeron gluon density $f_{g/P}(\beta)$ is peaked at large
$\beta$ for small scales, single diffractive events will represent a sizeable
fraction of all produced Higgs bosons with an expected better-than-average
signal-to-background ratio.


title:
Low Energy Phenomena in a Model With Symmetry Group SUSY SO(10) X Delta
  (48) X U(1)

abstract:
  Fermion masses and mixing angles including that of neutrinos are studied in a
model with symmetry group SUSY $SO(10)\times \Delta (48) \times U(1)$.
Universality of Yukawa coupling of superfields is assumed. The resulting
texture of mass matrices in the low energy region depends only on a single
coupling constant and VEVs caused by necessary symmetry breaking. 13 parameters
involving masses and mixing angles in the quark and charged lepton sector are
successfully described by only five parameters with two of them determined by
the scales of U(1), SO(10) and SU(5) symmetry breaking compatible with the
requirement of grand unification and proton decay. The neutrino masses and
mixing angles in the leptonic sector are also determined with the addition of a
Majorana coupling term. It is found that LSND $\bar{\nu}_{\mu}\rightarrow
\bar{\nu}_{e}$ events, atmospheric neutrino deficit and the mass limit put by
hot dark matter can be naturally explained. Solar neutrino puzzle can be solved
only by introducing sterile neutrino with one additional parameter. More
precise measurements of $\alpha_{s}(M_{Z})$, $V_{cb}$, $V_{ub}/V_{cb}$,
$m_{b}$, $m_{t}$, as well as various CP violation and neutrino oscillation
experiments will provide crucial tests of the present model.


title:
Reanalysis of the EMC charm production data with extrinsic and intrinsic
  charm at NLO

abstract:
  A calculation of the next-to-leading order exclusive extrinsic charm quark
differential distributions in deeply inelastic electroproduction has recently
been completed. Using these results we compare the NLO extrinsic contributions
to the charm structure function $F_2(x,Q^2,m_c^2)$ with the corresponding NLO
intrinsic contributions. The results of this analysis are compared with the EMC
DIS charm quark data and evidence for an intrinsic charm component in the
proton is found.


title: Top-bottom doublet in the sphaleron background

abstract:
  We consider the top-bottom doublet in the background of the sphaleron for the
realistic case of large non-degeneracy of fermion masses, in particular $m_b=5$
GeV and $m_t=175$ GeV. We propose an axially symmetric $(r,\theta)$-dependent
ansatz for fermion fields and investigate the effects of the non-degeneracy on
them. The exact solution is described, with an error less than 0.01\%, by a set
of ten radial functions. We also propose an approximate solution, in the
$m_b/m_t\rightarrow 0$ limit, with an error ${\cal O}(m_b/m_t)$. We have found
that the effects of non-degeneracy provide a $\theta$-dependence typically
$\sim 10\%$.


title: Fermion Fluctuation Determinant and Sphaleron Bound

abstract:
  We investigate analytically the fermionic fluctuation determinant at finite
temperatures in the minimal standard model, including all operators up to
dimension 6 and all contributions to the effective potential to all orders in
the high $T$ expansion, to 1 loop. We apply the results to find corrections to
the Sphaleron erasure rate in the broken phase. We conclude that the analytic
treatment of fermions is very reliable and that there is a great deal of baryon
erasure after the phase transition for any physical Higgs mass.


title: On the Convergence of Perturbative QCD at High Temperature

abstract:
  The free energy for QCD at high temperature $T$ is calculated to order $g^5$
using effective-field-theory methods to separate the contributions from the
momentum scales $T$ and $gT$. The effects of the scale $T$ enter through the
coefficients in the effective lagrangian for the 3-dimensional effective theory
obtained by dimensional reduction. The perturbation series for these
coefficients seem to be well-behaved if the running coupling constant is
sufficiently small: $\alpha_s(2 \pi T) \ll 1$. For the contribution to the free
energy from the scale $gT$, the perturbation series is well-behaved only if
$\alpha_s(2 \pi T)$ is an order of magnitude smaller. The implication for
applications of perturbative QCD to the quark-gluon plasma are briefly
discussed.


title:
$\eta \to \pi^0 \gamma \gamma$ to ${\cal{O}}(p)^6$ in Chiral
  Perturbation Theory

abstract:
  The decay $\eta \to \pi^0 \gamma \gamma$ is discussed in the framework of
SU(3) chiral perturbation theory. The process is dominated by the
${\cal{O}}(p^6)$ in the momentum expansion where tree-level amplitudes from the
effective Lagrangian ${\cal{L}}^6$ enter together with one--loop contributions
from ${ \cal{L}}^4$ and two--loop contributions from ${\cal{L}}^2$. We estimate
the 6 independent ${\cal{L}}^6$ coupling constants by resonance saturation
consistent with the pion production process $\gamma \gamma \to \pi^0 \pi^0$ and
calculate the pion--loop part of the one- and two--loop amplitude. Predictions
for the total rate and spectrum of $\eta \to \pi^0 \gamma \gamma$ are given
together with a discussion of the uncertainties involved.


title: The QCD Perspective on Lifetimes of Heavy-Flavour Hadrons

abstract:
  Over the last few years a theoretical treatment for the weak decays of
heavy-flavour hadrons has been developed that is genuinely based on QCD. Its
methodology is described as it applies to total lifetimes, and the underlying
theoretical issues are discussed. Theoretical expectations are compared with
present data. One discrepancy emerges: the beauty baryon lifetime appears to be
significantly shorter than predicted. The ramifications of those findings are
analyzed in detail, and future refinements are described.


title: QCD Corrections to Inelastic $J/\psi$ Photoproduction

abstract:
  We present a complete calculation of the higher-order perturbative QCD
corrections to inelastic photoproduction of $J/\psi$ particles. A comprehensive
analysis of total cross sections and differential distributions for the energy
range of the fixed-target experiments and for inelastic $J/\psi$
photoproduction at HERA is performed. The cross section and the $J/\psi$ energy
spectrum are compared with the available photoproduction data including first
results from HERA. This analysis will not only provide information on the gluon
distribution of the proton but appears to be a clean test for the underlying
picture of quarkonium production as developed so far in the perturbative QCD
sector.


title:
$J/\psi$ production as a probe of charge symmetry violations and nuclear
  corrections in parton distributions

abstract:
  We investigate the sensitivity of $J/\Psi$ production in proton-neutron and
proton-deuteron collisions to charge symmetry violations in the parton
distributions as well as to nuclear corrections. It is found that the effects
of charge symmetry violations in the quark distributions are confined to large
$x_F$ and difficult to measure in experiments currently being planned. However,
from proton-deuteron experiments it should be possible to isolate nuclear
corrections to the gluon distribution.


title: CP Violation in $Lambda \to p \pi^-$ Beyond the Standard Model

abstract:
  The $\cp$ violating asymmetry $A(\Lambda^0_-)$ has been estimated to occur at
the level of a few times $10^{-5}$ within the minimal standard model. The
experiment E871 expects to reach a sensitivity of $10^{-4}$ to the asymmetry
$A(\Lambda^0_-)+A(\Xi^-_-)$. In this paper we study some of the implications of
such a measurement for $\cp$ violation beyond the minimal standard model. We
find that it is possible to have $A(\Lambda^0_-)$ at the few times $10^{-4}$
level while satisfying the constraints imposed by the measurements of $\cp$
violation in kaon decays.


title: More Conservation Laws and Sum Rules in the Heavy Quark Limit

abstract:
  This is the continuation of a previous article, in which the Bjorken and
Voloshin sum rules were interpreted as statements of conservation of
probability and energy. Here the formalism is extended to higher moments of the
Hamiltonian operator. From the conservation of the second moment of the
Hamiltonian operator one can derive a sum rule which, in the small velocity
limit, reduces to the Bigi--Grozin--Shifman--Uraltsev--Vainshtein (BGSUV) sum
rule. On the other hand, the conservation of the third moment of the
Hamiltonian operator gives a new sum rule, which is related to the matrix
element of the heavy quark counterpart of the Darwin term in atomic physics.
The general case of the higher order moments is also discussed.


title: Phases in the MSSM

abstract:
  The effect of CP violating phases in the MSSM on the relic density of the
lightest supersymmetric particle (LSP) is considered. In particular, the upper
limits on the LSP mass are relaxed when phases in the MSSM are allowed to take
non-zero values and when the LSP is predominantly a gaugino (bino). Previous
limits of $\mb \la 250$ GeV for $\Omega h^2 < 0.25$ can be relaxed to $\mb \la
650$ GeV. The additional constraints imposed by the neutron and electron
electric dipole moments induced by these phases are also considered. Though
there is some restriction on the phases, the bino mass may still be as large as
$\sim$ 350 GeV and certain phases can be arbitrarily large.


title: Landau-Pomeranchuk-Migdal effect for nuclear matter in QCD

abstract:
  Soft photon and gluon radiation off a fast quark propagating through nuclear
matter is discussed. The close anology between the Landau - Pomeranchuk -
Migdal (LPM) effect in QED and the emission of soft gluons, suggested in ref.
\cite{BDPS} for ``hot" plasma, is confirmed and the relation between Mueller's
approach and traditional calculations is established. It is shown that
perturbative QCD can be applied to take into account the LPM coherent
suppression both for photon and gluon induced radiation. The formulae for the
photon and gluon radiation densities are presented.


title:
An Overview of $D^0\bar{D}^0$ Mixing Search Techniques: Current Status
  and Future Prospects

abstract:
  The search for $D^0\bar{D}^0$ mixing may carry a large discovery potential
for new physics. This paper discusses the techniques, current experimental
status, and future prospects for the mixing search. Some new ideas, applicable
to future mixing searches, are introduced. In this paper, the importance of
separately measuring the decay rate difference and the mass difference of the
two CP eigenstates (in order to observe New Physics) has been emphasized, since
the theoretical calculations for long distance effects are still plagued by
large uncertainties.


title:
Dynamical Models for Light Higgs Doublets in Supersymmetric Grand
  Unified Theories

abstract:
  We consider a supersymmetric hypercolor gauge theory with six flavors of
quarks interacting strongly at the grand unification scale. This model solves
the most serious problem -- doublet-triplet splitting in the grand unified
theories. We also show that the dangerous dimension-five operators for nucleon
decays are suppressed simultaneously, which makes our model yet more
attractive.


title:
On the cancelation of quantum-mechanical corrections at the periodic
  motion

abstract:
  The paper contains description of the path integrals in the action-angle
phase space. It allows to split the action and angle degrees of freedom and to
show that the angular quantum corrections cancel each other if the classical
classical trajectory is periodic. The example considered in the paper shows
that the quantum problem can be quasiclassical over the part (angular in the
considered case) degrees of freedom.


title: Hidden top quark decays to charged Higgs scalars at the Tevatron

abstract:
  Charged Higgs scalars light enough to contribute to top quark decays are
possible in various non--minimal Higgs models. We show that such a decay would
be consistent with the current Tevatron data, and will remain hidden until a
larger luminosity can be achieved.


title:
Strategies for Fixing the CKM-angle $\gamma$ and Obtaining Experimental
  Insights into the World of Electroweak Penguins

abstract:
  Using the $SU(3)$ flavour symmetry of strong interactions, we propose
strategies for extracting both the CKM-angle $\gamma$ and the $\bar b\to\bar
uu\bar s$ tree-level amplitude $T'$. We present also an approximate approach
using the branching ratios for the modes $B^+\to\pi^+ K^0$, $B^0_d\to\pi^-
K^+$, $\bar B^0_d\to\pi^+ K^-$ and $B^+\to\pi^+\pi^0$ which should be rather
promising from the experimental point of view. The quantities $\gamma$ and $T'$
determined this way may well be used as an input to control electroweak
penguins in nonleptonic $B$-decays as has been discussed in previous work.
Following these lines, we propose strategies for obtaining quantitative
insights into the physics of the electroweak penguin operators and performing
some consistency checks. As a by-product, we derive an upper bound of $6^\circ$
for the uncertainty originating from electroweak penguins in the
$\alpha$-determination by means of $B\to\pi\pi$ decays.


title:
Neutrino Masses and Mixing Angles in a Supersymmetric
  SU(4)$\otimes$SU(2)$_L\otimes$SU(2)$_R$ Model

abstract:
  We consider the problem of neutrino masses and mixing angles in a
supersymmetric model based on the gauge group
SU(4)$\otimes$SU(2)$_L\otimes$SU(2)$_R$ broken at the scale $M_X\approx
10^{16}$ GeV. We extend a previous operator analysis of the charged lepton and
quark masses and mixing angles in this model to include the neutrino sector,
assuming a universal Majorana mass $M$ for the right-handed neutrinos. The
Dirac part of the neutrino matrix is then fixed and the physical neutrino
masses and magnitudes of all of the elements of the leptonic mixing matrix are
then predicted in terms of the single additional parameter $M$. The successful
ansatze predict a tau neutrino mass in the relevant range for the dark matter
problem and structure formation, muon and electron neutrinos consistent with
the MSW solution to the solar neutrino problem, and tau-muon neutrino mixing at
a level which should soon be observed by the CHORUS and NOMAD experiments.


title: Minijet activity in high E_T jet events at the Tevatron

abstract:
  Gluon bremsstrahlung in scattering events with high transverse momentum jets
is expected to increase markedly with the hardness (sum E_T) of the primary
event. Within perturbative QCD we estimate a probability of order unity to see
additional minijets with E_T >~ 15 GeV in ``dijet'' events with sum E_T > 400
GeV. The veto of such minijets is a promising background rejection tool for the
Higgs search at the LHC.


title:
Up--dating for the paper ``The mass of the Higgs boson in the Standard
  Model from precision tests'' (MPI--Ph/95--39, hep-ph/9505308)

abstract:
  The bounds on the Higgs mass in the Standard Model are re-analyzed using the
precision electroweak data presented at the International Europhysics
Conference on High Energy Physics, Brussels, 27 July -- 2 August, 1995


title: Probing New Physics from the Single-Top Production

abstract:
  We show that the production rate of the single-top quark event from the
$W$-gluon fusion process is sensitive to new physics which strongly modifies
the interactions of the top quark. The measurement of its production rate gives
the partial decay width of the top quark which combined with the branching
ratio measurement from the $t \bar t$ pair event determines the lifetime of the
top quark.


title: Top Quark Physics at the Tevatron

abstract:
  We discuss physics of the top quark at the Fermilab Tevatron. By the year
2000, many properties of the top quark can be measured at the Tevatron.


title: New Insights into the Production of Heavy Quarkonium

abstract:
  Recent data from the Tevatron have revealed that the production rate of
prompt charmonium is more than an order of magnitude larger than the best
theoretical predictions of a few years ago. This surprising result can be
understood by taking into account new production mechanisms that include
fragmentation and the formation of charmonium from color-octet $c \bar c$
pairs.


title: Hyperon Polarizabilities in the Bound State Soliton Model

abstract:
  A detailed calculation of electric and magnetic static polarizabilities of
octet hyperons is presented in the framework of the bound state soliton model.
Both seagull and dispersive contributions are considered, and the results are
compared with different model predictions.


title: Challenging weak-scale supersymmetry at colliders

abstract:
  Experimental searches for supersymmetry are entering a new era. As future
experiments explore the mass range above the current lower bounds on
superpartner masses, a failure to observe signals of superpartner production
will begin to erode the central motivation for supersymmetry at the weak scale.
In this article we present a detailed examination of which regions of
supersymmetric parameter space are most natural and the extent to which
weak-scale supersymmetry becomes unnatural if no superpartners are observed at
LEP-II, the Tevatron, possible upgrades of these machines, and the LHC.


title:
Bose-Einstein Correlations for Three-Dimensionally Expanding,
  Cylindrically Symmetric, Finite Systems

abstract:
  The parameters of the Bose-Einstein correlation function may obey an {\it
$M_t$-scaling}, as observed in $S + Pb$ and $Pb + Pb$ reactions at CERN SPS.
This $M_t$-scaling implies that the Bose-Einstein correlation functions view
only a small part of the big and expanding system. The full sizes of the
expanding system at the last interaction are shown to be measurable with the
help the invariant momentum distribution of the emitted particles. A vanishing
duration parameter can also be generated in the considered model-class with a
specific $M_t$ dependence.


title:
Bose-Einstein Correlations for Expanding Finite Systems or from a Hot
  Fireball to a Snow-Flurry

abstract:
  Most boson emitting sources contain a core of finite dimensions surrounded by
a large halo, due to long-lived resonances like $\omega,\eta,\eta',K^{0}$ etc.
When the Bose-Einstein correlation (BEC) function of the core can be determined
we show that its intercept ($\lambda$) measures, as a function of momentum, the
square of the fraction of core particles produced. A simultaneos measurement of
BEC and the single-particle distributions can thus determine the
characteristics of the core. If the geometrical sizes of the core are
sufficiently large the parameters of the BEC function obey the $m_{t}$-scaling
observed in $SPb$ and $PbPb$ reactions at CERN. The model can describe the
measurements of the single- and two-particle distributions in the central
region of $SPb$ reactions. A fit to experimental data shows that the freeze-out
of hadrons occurs at a larger volume and at a much lower temperature than that
given by the measurement of the inverse slope of the $m_{t}$-spectrum and
standard BEC analysis.


title: Residual New Physics Effects in $e^+e^-$ and $\gamma\gamma$ Collisions

abstract:
  We present a set of studies concerning the description of New Physics (NP)
effects caracterized by a scale much higher than the electroweak scale. We show
that both present experimental results and several types of theretical
considerations about the Standard Model (SM) and NP suggest a hierarchy among
the sectors in which NP manifestations should appear. We concentrate on
residual effects described by effective lagrangians involving bosonic and/or
heavy quark fields. For each operator we propose an unambiguous definition of
the NP scale given by the energy at which unitarity is saturated. We also
consider the possible existence of Higher Vector Bosons.
  We then study the tests realizable at present and future colliders. We start
from the analysis of the high precision tests at Z peak, discussing separately
the constraints obtained from the light fermionic sector and those due to the
$b\bar b$ sector. We then consider the process $e^+e^-\to f\bar f$ at higher
energies (LEP2 and NLC) and we propose the "Z peak subtracted representation"
which allows to automatically take into account Z peak constraints and to
describe several types of NP effects at any other energy. Applications to
various NP effects (Higher Vector Bosons, Technicolour resonances, Anomalous
Gauge Boson couplings) are given. We then concentrate on several bosonic
processes, $e^+e^-\to W^+W^-$, $HZ$, $H\gamma$, and $\gamma\gamma$ collisions
producing boson pairs or a single Higgs. We study the sensitivities to the
various operators involved in the effective lagrangian and we propose ways to
disentangle them. The NP scales which can be felt vary from a few TeV at LEP2
up to 200 TeV in single H production at NLC.


title:
Universal and Non Universal New Physics Effects in a General
  Four-fermion Process: a Z-peak Subtracted Approach

abstract:
  We calculate, using a Z-peak subtracted representation of four-fermion
processes previously illustrated for the case of electron-positron annihilation
into charged lepton-antilepton, the corresponding expressions of the new
physics contributions for the case of final quark-antiquark states, allowing
the possibility of both universal and non universal effects. We show that, in
each case, the main result obtained for the final lepton channel can be
generalized, so that every experimentally measurable quantity can be expressed
in terms of input parameters \underline{measured} on Z resonance, of
$\alpha(0)$ and of a small number of subtracted one loop expressions. Some
examples of models are considered for several c.m. energy values, showing that
remarkable simplifications are often introduced by our approach. In particular,
for the case of a dimension-six lagrangian with anomalous gauge couplings, the
same reduced number of parameters that would affect the observables of final
leptonic states are essentially retained when one moves to final hadronic
states. This leads to great simplifications in the elaboration of constraints
and, as a gratifying byproduct, to the possibility of making the signal from
these models clearly distinguishable from those from other (both universal and
non universal) competitors.


title:
Lowest tensor-meson resonances contributions to the chiral perturbation
  theory low energy coupling constants

abstract:
  The contributions of the lightest tensor-meson resonances to the low-energy
coupling constants of second order chiral perturbation theory with two flavours
are evaluated and compared with the available phenomenological information as
well as with similar results for other resonances.


title: Spherically symmetric quark-gluon plasma field configurations

abstract:
  We study field configurations in a hot quark-gluon plasma with spherical
symmetry. We show that the electric fields point into radial direction and
solve the effective non-abelian equations of motions. The corresponding charge
density has a localized contribution which has a gauge invariant interpretation
as a pointlike color charge. We discuss configurations oscillating periodically
in time. Furthermore, we calculate the electric field induced by a constant
local charge that is removed from the plasma for $t>0$ as a model of a decaying
heavy quark.


title: Quantization of the tachyonic field and the preferred frame

abstract:
  A consistent quantization scheme for imaginary-mass field is proposed. It is
related to an appropriate choice of the synchronization procedure (definition
of time), which guarantee an absolute causality in agreement with Lorentz
covariance. In that formulation a possible existence of field excitations
(tachyons) distinguish an inertial frame (tachyon privileged frame of
reference) {\em via} spontaneous breaking of the so called synchronization
group. In this scheme relativity principle is broken but Lorentz symmetry is
exactly preserved in agreement with local properties of the observed world.


title: Are Neutrinos Spinorial Tachyons?

abstract:
  Quantum field theory of space-like particles is investigated in the framework
of absolute causality scheme preserving Lorentz symmetry. It is shown that
tachyons are associated with unitary orbits of Poincar\'e mappings induced from
SO(2) little group instead of SO(2,1) one. Therefore the corresponding
elementary states are labelled by helicity. A particular case of the helicity
$\lambda=\pm{1/2}$ is investigated in detail and a corresponding consistent
field theory is proposed. In particular, it is shown that the Dirac-like
equation proposed by Chodos {\it et al}., inconsistent in the standard
formulation of QFT, can be consistently quantized in the presented framework.
This allows us to treat more seriously possibility that neutrinos can be
fermionic tachyons as it is suggested by the present experimental data about
neutrino masses.


title: Electroproduction and Hadroproduction of Light Gluinos

abstract:
  In a class of supergravity models, the gluino and photino are massless at
tree level and receive small masses through radiative corrections. In such
models, one expects a gluino-gluon bound state, the $R_0$, to have a mass of
between 1.0 and 2.2 GeV and a lifetime between $10^{-10}$ and $10^{-6}$
seconds. Applying peturbative QCD methods (whose validity we discuss), we
calculate the production cross sections of $R_0$'s in $e-p$, $\pi-p$, $K-p$,
$\overline{p}-p$ and $p-p$ collisions. Signatures are also discussed.


title: Polarized Parton Distribution Functions Reexamined

abstract:
  The hard-gluonic contribution to the first moment of the polarized proton
structure function $g_1^p(x)$ is dependent of the factorization convention
chosen in defining the quark spin density and the hard cross section for
photon-gluon scattering. Two extremes of interest, namely gauge-invariant and
chiral-invariant factorization schemes, are considered. We show that in order
to satisfy the positivity constraint for sea and gluon polarizations, the
polarized valence quark distributions should fully account for the observed
$g_1^p(x)$ at $x\gsim 0.2\,$. This together with the first-moment and
perturbative QCD constraints puts a pertinent restriction on the shape of
$\Delta u_v(x)$ and $\Delta d_v(x)$. The spin-dependent sea distribution in the
gauge-invariant factorization scheme is extracted from the data of $g_1^p(x)$.
It is shown in the chiral invariant scheme that it is possible to interpret the
$g_1^p(x)$ data with anomalous gluonic contributions, yet a best least $\chi^2$
fit to the data implies a gluon spin distribution which violates the positivity
condition $|\Delta G(x)|\leq G(x)$. We then propose a more realistic set of
parton spin distributions with sea polarization and with a moderate value of
$\Delta G$. The polarized parton distributions in this work are presented in
the next-to-leading order of QCD at the scale $Q^2=10\,{\rm GeV}^2\,$.
Predictions for the polarized structure functions $g_1^n(x)$ of the neutron and
$g_1^d(x)$ of the deuteron are given.


title: On Quadratic Divergences and the Higgs Mass

abstract:
  The quadratic divergences in the scalar sector of the standard model are
considered. Since the divergences are present also in the unbroken theory, a
natural scale for the divergence formula is proposed to be at the scale of new
physics. The implications of top quark mass on the Higgs mass are investigated
by means of the renormalization group equations. The Coleman-Weinberg mechanism
for spontaneous symmetry breaking is also considered.


title:
Optimized $\delta$-Expansion and Triviality or Non-Triviality of Field
  Theories

abstract:
  We use a very simple version of the optimized (linear) $\delta $ - expansion
by scaling the free part of the Lagrangian with a variational parameter. This
method is well suited to calculate the renormalized coupling constant in terms
of the free one and the cutoff. One never has to calculate any new Feynman
graphs but simply can modify existing results from the literature. We find that
$\Phi _4^4$ -theory as well as QED are free in the limit where the cutoff goes
to infinity. In contrast to this, the structure of Yang-Mills theories enforces
a special choice of the Lagrangian of the $\delta $ - expansion. Together with
the change in the sign of the $\beta $ - function, this leads to a different
behavior and allows Yang-Mills theory to become non trivial.


title:
Further experimental tests for simple relations between unpolarized and
  polarized quark parton distributions

abstract:
  Some simple relations between unpolarized and polarized quark parton
distributions have direct experimental consequences which will be presented
here. In particular, we will see that it is possible to relate the deep
inelastic structure functions $F_2$ and $g_1$, both for proton and deuteron, in
fair agreement with experimental data.


title:
Trivial Vacua, High Orders in Perturbation Theory and Nontrivial
  Condensates

abstract:
  In the limit of an infinite number of colors, an analytic expression for the
quark condensate in $QCD_{1+1}$ is derived as a function of the quark mass and
the gauge coupling constant. For zero quark mass, a nonvanishing quark
condensate is obtained. Nevertheless, it is shown that there is no phase
transition as a function of the quark mass. It is furthermore shown that the
expansion of $\langle 0 | \overline{\psi}\psi |0\rangle$ in the gauge coupling
has zero radius of convergence but that the perturbation series is Borel
summable with finite radius of convergence. The nonanalytic behavior $\langle 0
| \overline{\psi}\psi |0\rangle \stackrel{m_q\rightarrow0}{\sim} - N_C
\sqrt{G^2}$ can only be obtained by summing the perturbation series to infinite
order. The sum-rule calculation is based on masses and coupling constants
calculated from 't Hooft's solution to $QCD_{1+1}$ which employs LF
quantization and is thus based on a trivial vacuum. Nevertheless the chiral
condensate remains nonvanishing in the chiral limit which is yet another
example that seemingly trivial LF vacua are {\it not} in conflict with QCD
sum-rule results.


title: Standard Model Anomalies in Curved Space-Time with Torsion

abstract:
  Using the Fujikawa and the heat-kernel methods we make a complete and
detailed computation of the global, gauge and gravitational anomalies present
in the Standard Model defined on a curved space time with torsion. We find new
contributions coming from curvature and torsion terms to the leptonic number
anomaly (so that $B-L$ is not conserved any more), to the $U(1)_Y$ gauge and to
the mixed $U(1)_Y$-gravitational anomalies, but the gauge anomaly cancellation
conditions on the hypercharges remain the same. We also find that the
condition, usually related to the cancellation of the mixed
$U(1)_Y$-gravitational anomaly, can be reobtained in the context of the
Standard Model in flat space-time by requiring the cancellation of the global
Lorentz anomaly without any reference to gravitation.


title: Signs and Polarized/Magnetic versions of the Casimir Forces

abstract:
  We consider versions of the Casimir effect where the force can be controlled
by changing the angle between two Casimir ``plates'' or the temperature of two
nearby rings. We also present simple arguments for the sign of Casimir forces.


title: Low-energy effects of Charged Higgs with general Yukawa couplings

abstract:
  We study a model with two Higgs doublets where FCNC are allowed at
tree-level. In this model, the interactions of charged Higgs with fermions
($H^\pm f \bar{f'}$), include a term that is not proportional to the fermion
masses, which we constraint using the following low-energy processes: i) tau
decays ($\tau \to \nu_{\tau} e\nu_e, \nu_{\tau}\mu\nu_{\mu}, \nu_{\tau}\pi$),
ii) leptonic decays of pseudoscalar mesons ($\pi, K \to \ell\nu_{\ell}$) and
iii) semileptonic b-decays. With these constraints it is possible to make
predictions; we illustrate this by presenting the rates for the (FCNC) decay
$c\to u+\gamma$, the (second class-current) decay $\tau\to \nu_{\tau}+
\eta\pi$, and also the theoretical value of the neutron life-time.


title: S to P wave form factors in semi-leptonic B decays

abstract:
  We apply HQET to semi-leptonic $B$ and $B_{s}$ meson decays into the observed
charmed $P$ wave states. In order to examine the sensitivity of the results to
the choice of a specific model, we perform all calculations using several
different meson models, and find that uncertainty introduced by the choice of a
particular model is about 30\%. Specifically, assuming $\tau_{B}=1.50ps$ and
$V_{cb}= 0.040$, we obtain branching ratios of $(0.27\pm 0.08)\%$ and $(0.45\pm
0.14)\%$ for $B\rar D_{1}l\bar{\nu}_{l}$ and $B\rar D_{2}^{*}l\bar{\nu}_{l}$
decays, respectively.


title:
Instanton--anti-instanton pair induced contributions to $R_{e^+e^-\to
  hadrons}$ and $R_{\tau \to hadrons}$

abstract:
  The instanton--anti-instanton pair induced asymptotics of perturbation theory
expansion for the cross section of electron--positron pair annihilation to
hadrons and hadronic width of $\tau$-lepton was found. For $N_f = N_c$ the
nonperturbative instanton contribution is finite and may be calculated without
phenomenological input. The instanton induced peturbative asymptotics was shown
to be enhanced as $(n+10)!$ and in the intermediate region $n<15$ may exceed
the renormalon contribution. Unfortunately, the analysis of $\sim 1/n$
corrections shows that for $n \sim 10$ the obtained asymptotic expressions are
at best only the order of magnitude estimate. The asymptotic series for $R_{e^+
e^- \rightarrow hadrons}$ , though obtained formally for $N_f =N_c$, is valid
up to energies $\sim 15$Gev. The instanton--anti-instanton pair nonperturbative
contribution to $R_{\tau \rightarrow hadrons}$ blows up. On the one hand, this
means that instantons could not be considered {\it ab--initio} at such
energies. On the other hand, this result casts a strong doubt upon the
possibility to determine the $\alpha_s$ from the $\tau$--lepton width.


title: Spectroscopy and Decays of Heavy Mesons

abstract:
  Assuming Coulomb-like as well as confining scalar potential, we have solved
Shr\"odinger equation perturbatively in $1/m_Q$ with a heavy quark mass $m_Q$.
The lowest order equation is examined carefully. Mass levels are fitted with
experimental data for $D/B$ mesons at each level of perturbation. Meson wave
functions obtained thereby can be used to calculate ordinary form factors as
well as Isgur-Wise functions for semileptonic weak decays and other physical
quantities. All the above calculations are expanded in $1/m_Q$ order by order
to determine parameters as well as to compare with results of Heavy Quark
Effective Theory.


title: Top-Charm flavor changing contributions to the effective $bsZ$ vertex

abstract:
  We analyze the effects of a tree level flavor changing $tcZ$ vertex induced
by a mixing with new isosinglet $Q=2/3$ quarks, on the effective $bsZ$ vertex.
We compute the contributions arising from the new electroweak penguin diagrams
involving one insertion of the $tcZ$ vertex. We show that a generalized GIM
mechanism ensures the cancellation of the mass independent terms as well as of
the new divergences. Unexpectedly, the presence of a $tcZ$ coupling cannot
enhance the rates for the $Z$ mediated flavor changing decays \bsll\ and \bsnn,
implying that these processes cannot be used to set limits on the $tcZ$
coupling. The additional effects of the heavy isosinglets are compared with the
well studied effects of new isodoublets appearing in multi-generational models.


title: Spectroscopy and large scale wave functions

abstract:
  We discuss the relevance of long wavelength excitations for the low energy
spectrum of QCD, and try to develop an efficient method for solving the
Schrodinger equation, and for extracting the glueball masses and long
wavelength functions of the ground and excited states. Some technical problems
appearing in the calculations of SU(3) gauge theory are discussed.


title: QCD Physics Lessons of Z0 Decay

abstract:
  This talk contains a subjective selection of interesting results on Z$^0$
decays, presented by the LEP and SLC groups. The emphasis is on soft and
semihard QCD physics. Results are put in a theoretical context, and the limits
of our current understanding are stressed. Topics covered include event
measures, prompt photons, coherence and string effects, data and theory for
particle rates and spectra, particle correlations and Bose--Einstein effects.


title: Spin-dependent non-singlet structure functions in next-to-leading order

abstract:
  We study in detail the flavor-non-singlet component of polarized structure
functions in the framework of a consistent and complete next-to-leading order
(${\cal O}(\alpha_s))$ analysis. In this context, we discuss some important
features of the calculation of the next-to-leading order corrections.
Particular emphasis is put on the $Q^2$-evolution of sum-rules for the first
moments of the non-singlet structure functions which, as we show, could serve
to explore $SU(2)$ and $SU(3)$ breaking effects in relations between baryonic
$\beta$-decay matrix elements and in the proton's polarized sea. Furthermore we
make predictions for polarized non-singlet structure functions measurable in a
conceivable $\vec{e}\vec{p}$ collider mode of HERA.


title:
SU(3) Breaking Effects in Hyperon Semi-Leptonic Decays and the
  extraction of F and D

abstract:
  The analysis of hyperon semi-leptonic decay data is re-examined in the light
of a recent suggestion that SU(3) symmetry breaking effects may be taken into
account by applying a correction to the $F/D$ ratio obtained via naive linear
extrapolation in the hyperon masses. Comparison is made with the physically
better motivated approach of applying so-called centre-of-mass corrections.
This study (including all available data) reveals certain short-comings of the
former of the above treatments, highlights some interesting aspects of this
type of analysis and attempts to pinpoint the decay data that might usefully be
improved. A tantalising result of the SU(3) breaking analysis performed here is
that the magnitude of recoil correction required by the data corresponds
closely to that required for the standard explanation of the reduction of $\gA$
from its SU(6) value of 5/3. We also comment on other recent suggestions for
taking into account the effects of SU(3) breaking. Finally a few remarks are
made on the relevance for predicting the flavour non-singlet contribution to
the proton $g_1$ and the Ellis-Jaffe sum rule.


title:
Spin asymmetries in lepton-proton and proton-proton diffractive
  reactions

abstract:
  It is shown that the longitudinal double spin asymmetry $A_{ll}$ in polarized
diffractive $Q \bar Q$ production depends strongly on the spin structure of the
quark-pomeron vertex. Relevant experiments will be possible at HERA with a
polarized proton beam.


title: Behavior of Diffractive Parton Distribution Functions

abstract:
  Diffractive parton distribution functions give the probability to find a
parton in a hadron if the hadron is diffractively scattered. We provide an
operator definition of these functions and discuss their relation to
diffractive deeply inelastic scattering and to photoproduction of jets at HERA.
We perform a calculation in the style of ``constituent counting rules'' for the
behavior of these functions when the detected parton carries almost all of the
longitudinal momentum transferred from the scattered hadron.


title: Global anomalies and the gauge-boson equivalence theorem

abstract:
  We discuss the various resolutions which have been suggested in the
literature for the way that the equivalence theorem can be satisfied in
theories with global anomalies. We provide a model-independent proof for the
resolution originally suggested in the context of a toy model by Kilgore.


title: Field Theoretical Methods in Cosmology

abstract:
  To optimally utilize all the exciting cosmological data coming in we need to
sharpen also the theoretical tools available to cosmologists. One such
indispensible tool to understand hot big bang cosmology is finite temperature
field theory. We review and summarise the efforts made by us to use finite
temperature field theory to address issues of current interest to cosmologists.
An introduction to both the real time and the imaginary time formalisms is
provided.
  The imaginary time formalism is illustrated by applying it to understand the
interesting possibilty of Late Time Phase Transitions. Recent observations of
the space distribution of quasars indicate a very notable peak in space density
at a redshift of $2$ to $3$. It is pointed out that this may be the result of a
phase transition which has a critical temperature of roughly a few meV (in the
cosmological units, $~\hbar = c =k = 1$), which is natural in the context of
massive neutrinos. In fact, the neutrino masses required for quasar production
and those required to solve the solar neutrino problem by the MSW mechanism are
consistent with each other. As a bonus, the cosmological constant implied by
this model may also help resolve the discrepancy between the recently measured
value of the Hubble Constant and the age of the universe.
  We illustrate the real time formalism by studying one of the most important
time-dependent and non-equilibrium phenomena associated with phase transitions.
The non-equilibrium dynamics of the first stage of the reheating process, that
is dissipation via particle production is studied in scalar field theories. We
show that a complete understanding of the mechanism of dissipation via particle
production requires a non-perturbative resummation. We then study


title: Natural Mass Matrices

abstract:
  We introduce the idea of natural mass matrices, an organizing principle
useful in the search for GUT scale quark mass matrix patterns that are
consistent with known CKM constraints and quark mass eigenvalues. An
application of this idea is made in the context of SUSY GUTs and some
potentially ``successful'' GUT scale mass patterns are found. The CKM
predictions of these patterns are presented and some relevant strong CP issues
are discussed.


title: Schr\"odinger Equation for Heavy Mesons Expanded in $1/m_Q$

abstract:
  Operating just once the naive Foldy-Wouthuysen-Tani transformation on the
Schr\"odinger equation for $Q\bar q$ bound states described by a hamiltonian,
we systematically develop a perturbation theory in $1/m_Q$ which enables one to
solve the Schr\"odinger equation to obtain masses and wave functions of the
bound states in any order of $1/m_Q$. It is shown that positive energy
projection with respect to the heavy quark sector of a wave function is, at
each order of perturbation, proportional to the 0-th order solution. There
appear also negative components of the wave function except for the 0-th order,
which contribute also to higher order corrections to masses.


title: A Study of Structure Functions for the Bag Beyond Leading Order

abstract:
  There has recently been surprising progress in understanding the spin and
flavor dependence of deep inelastic structure functions in terms of the same
physics needed in the simple quark models used for hadronic spectroscopy.
However, the corresponding scale is usually very low, casting doubt on the use
of leading order $QCD$ evolution. We show that the conclusions are not
significantly altered if one goes to next-to-leading order. In particular, the
excellent agreement with unpolarized and polarized valence quark distributions
is retained.


title: Are Glueballs and Hybrids Found?

abstract:
  The lightest scalar glueball and ground state hybrids may have been found. I
compare signals reported at this conference with theoretical expectations and
highlight the questions that need to be addressed in forthcoming experiments.


title: Implications of Heavy Top

abstract:
  Lecture at 23 ITEP Winter School. Manifestations of heavy top at low energies
(K- and B-mesons) and high energies (Z and W physics) are discussed


title: Are Diffractive Events at HERA due to a Gluemoron or a Quarkball?

abstract:
  We propose a means of distinguishing between gluon- and quark-seeded systems
that may in principle be measured in deep inelastic lepton scattering. As a
particular application, we discuss those HERA data on deep inelastic $ep$
scattering which contain a large rapidity gap in the final state. It is
standard to interpret these events as being due to ``pomeron" exchange,
although precisely what is meant by this remains unclear. Guided by data, we
make some rather general statements about these events and in particular we
discuss the potential for discerning whether the exchanged colour singlet
system can be interpreted as gluonic.


title: Reevaluation of the Hadronic Contribution to $\alpha(M_Z^2)$

abstract:
  We reevaluate the hadronic part of the electromagnetic vacuum expectation
value using the standard dispersion integral approach that utilizes the
hadronic cross section measured in $\ee$ experiments as input. Previous
analyses are based upon point-by-point trapezoidal integration which does not
treat experimental errors in an optimal way. We use a technique that weights
the experimental inputs by their stated uncertainties, includes correlations,
and incorporates some refinements. We find the five-flavor hadronic
contribution to the fractional change in the electromagnetic coupling constant
at $q^2=M_Z^2$, $\Delta\alpha(MZ)$, to be $0.02752\pm0.00046$, which leads to a
value of the electromagnetic coupling constant, $\alpha^{-1}(M_Z^2) =
128.96\pm0.06$. [This is an updated version of SLAC-PUB-6710 (hep-ph/9411353)
which fixes a small bias in the fitting procedure (1/3 of the change) and
incorporates a new and precise cross section measurement near charm threshold
(2/3 of the change).]


title: Testing the running of the QCD coupling in particle energy spectra

abstract:
  The spectra of charged particles in the energy variable $\xi = \log 1/x$
(``the hump backed plateau'') are analyzed in terms of moments in order to
investigate the sensitivity to the running of $\alpha_s$ in particular towards
small scales, and to further test thereby the local parton hadron duality
picture. The modified leading log approximation (MLLA) of QCD provides a very
satisfying description of the $e^+e^-$ data in the full range of c.m. energies
from about 1 up to 91 GeV. The same calculation but with fixed coupling
$\alpha_s$ yields moments which are inconsistent with the data already close to
threshold. In particular the soft particles ($E\le 1$~GeV) reflect directly the
running of $\alpha_s$.


title: Mass Bounds in Mirror-Fermion Models

abstract:
  Numerical simulations are performed on different lattice sizes of chiral U(1)
and SU(2) scalar-fermion models with explicit mirror pairs of fermions in the
broken symmetry phase. Relevance of these models to the electroweak theory is
discussed. Shift symmetry of the action is exploited to decouple the unwanted
mirror-fermion. Upper and lower bounds on the renormalized scalar mass as a
function of the renormalized fermion mass are obtained in the SU(2) version of
the model. Our numerical data are found to be in qualitative agreement with
one-loop results. No evidence for a nontrivial fixed point has been observed.
The mirror-fermion models are likely to be trivial in the continuum limit. Our
Monte Carlo data show that with a $180\, GeV$ top quark, the Standard Model
Higgs boson should have a mass between $100$ and $800\, GeV$.


title: Nucleon Spin: Summary

abstract:
  This talk summarises the discussions during the conference on the spin
structure of the nucleon held at Erice; July 1995. The summary focuses on where
we have come, where we are now, and the emerging questions that direct where we
go next in the quest to understand the nucleon spin.


title: On the Nonequilibrium Effective Potential

abstract:
  Nonequilibrium phenomena of the phase transitions are studied. It is shown
that due to finite relaxation time of the particle distributions, the use of
scalar background dependent distribution functions is inconsistent.This
observation may change the picture of rapid processes during the electroweak
phase transition, like subcritical bubble formation and propagation of bubble
walls.


title: Importance of Precision Measurements in the Tau Sector

abstract:
  $\tau$ decays provide a powerful tool to test the structure of the weak
currents and the universality of their couplings to the $W$ boson. The
constraints implied by present data and the possible improvements at the
$\tau$-charm Factory are analyzed.


title: Bounds on Neutrino Transition Magnetic Moments in Random Magnetic Fields

abstract:
  We consider the conversions of active to sterile Majorana neutrinos $\nu_{a}$
and $\nu_{s}$, due to neutrino transition magnetic moments in the presence of
random magnetic fields (r.m.f.) generated at the electroweak phase transition.
From a simple Schr\"{o}dinger-type evolution equation, we derive a stringent
constraint on the corresponding transition magnetic moments and display it as a
function of the domain size and field geometry. For typical parameter choices
one gets limits much stronger than usually derived from stellar energy loss
considerations. These bounds are consistent with the hypothesis of seeding of
galactic magnetic fields by primordial fields surviving past the re-combination
epoch. We also obtain a bound on active-sterile neutrino transition magnetic
moments from supernova energy loss arguments. For r.m.f. strengths in the range
$10^7$ to $10^{12}$ Gauss we obtain limits varying from $\mu_{as}^{\nu} \lsim
10^{-13}\mu_B$ to $\mu_{as}^{\nu} \lsim 10^{-18}\mu_B$, again much stronger
than in the case without magnetic fields.


title: Dynamical Left-Right Symmetry Breaking

abstract:
  We study a left--right symmetric model which contains only elementary gauge
boson and fermion fields and no scalars. The phenomenologically required
symmetry breaking emerges dynamically leading to a composite Higgs sector with
a renormalizable effective Lagrangian. We discuss the pattern of symmetry
breaking and phenomenological consequences of this scenario. It is shown that a
viable top quark mass can be achieved for the ratio of the VEVs of the
bi--doublet $\tan\beta\equiv\kappa/\kappa'$ =~ 1.3--4. For a theoretically
plausible choice of the parameters the right--handed scale can be as low as
$\sim 20 TeV$; in this case one expects several intermediate and low--scale
scalars in addition to the \SM Higgs boson. These may lead to observable lepton
flavour violation effects including $\mu\to e\gamma$ decay with the rate close
to its present experimental upper bound.


title: Upper bound on the $W_R$ mass in automatically R-conserving SUSY models

abstract:
  We show that in automatically R-conserving minimal SUSY left-right symmetric
models there is a theoretical upper limit on the mass of the right-handed $W_R$
boson given by $M_{W_R}\leq g M_{SUSY}/f$, where $M_{SUSY}$ is the scale of
supersymmetry breaking, g is the weak gauge coupling and $f$ is the Yukawa
coupling responsible for generating the right-handed neutrino masses. If
$M_{W_R}$ violates the above limit, the ground state of the theory breaks
electromagnetism. The only way to avoid this bound while keeping the theory
automatically R-conserving is to expand the theory to include very specific
kinds of additional multiplets and demanding unnatural finetuning of their
couplings.


title: Excited Leptonic States in Polarized e^-\gamma and e^+ e^- Collisions

abstract:
  We analyze the capability of the next generation of linear electron--positron
colliders to unravel the spin and couplings of excited leptons predicted by
composite models. Assuming that these machines will be able to operate both in
the $e^+e^-$ and $e^-\gamma$ modes, we study the effects of the excited
electrons of spin $\frac{1}{2}$ and $\frac{3}{2}$ in the reactions $e^-\gamma
\rightarrow e^-\gamma$ and $e^+e^- \rightarrow \gamma\gamma$. We show how the
use of polarized beams is able not only to increase the reach of these
machines, but also to determine the spin and couplings of the excited states.


title: Double Pomeron Jet Cross Sections

abstract:
  We treat hadron-hadron collisions where the final state is kinematically of
the kind associated with double-pomeron-exchange (DPE) and has large transverse
momentum jets. We show that in addition to the conventional factorized (FDPE)
contribution, there is a non-factorized (NDPE) contribution which has no
pomeron beam jet. Within a simple model we compute DPE-two-jet total and
differential cross sections at Tevatron energy scales, and show that the NDPE
contribution is dominant.


title: Effective Chiral Lagrangian from Dual Resonance Models

abstract:
  Parameters of the effective chiral lagrangian (EChL) of orders $O(p^4)$ and
$O(p^6)$ are extracted from low--energy behaviour of dual resonance models for
$ \pi\pi$ and $\pi K$ scattering amplitudes. Dual resonance models are
considered to be good candidates for the resonance spectrum and for hadronic
scattering amplitudes in the large $N_c$ limit of QCD. We discuss dual
resonance models in the presence of spontaneous and explicit chiral symmetry
breaking. Obtained parameters of the EChL are used to estimate chiral
corrections up to the sixth order to various low--energy characteristics of
$\pi\pi$ and $\pi K$ scattering amplitudes.


title:
Predictions of Neutralino Dark Matter Event Rates in Minimal
  Supergravity Unification

abstract:
  A detailed analysis of dark matter event rates in minimal supergravity models
(MSGM) is given. It is shown analytically that the lightest neutralino the
${{\tilde {Z}_{1}}}$ is the LSP over almost all of the parameter space, and
hence the natural candidate for cold dark matter (CDM). The radiative breaking
of $SU(2)\times U(1)$ constraints are shown to be crucial in determining the
expected event rates. Approximate analytic formulae are obtained to determine
the gaugino-higgsino content of the ${{\tilde{Z}_{1}}}$ particle.From this one
can deduce the behavior of the event rates as one varies the SUSY soft breaking
parameters and tan $\beta$. The constraint on the event rates due to the
recently measured $b\rightarrow s+\gamma$ decay is calculated. It is seen that
this data eliminates most of the parameter space where $\mu$ (the Higgs mixing
parameter) and $A_t$ (the t-quark cubic soft breaking parameter) have the same
sign. Since the t-quark is close to its Landau pole, $A_t$ is restricted to be
mostly positive, and so most of the $\mu>0$ part of the parameter space is
eliminated...


title: Lepton Oscillations

abstract:
  A simple but general proof is presented to show that Lorents covariance and
4-momentum conservation alone are sufficient to obtain muon oscillations in the
pion decay if the recoiling neutrinos oscillate.


title:
Dynamical Symmetry Breaking with Large Anomalous Dimension in Gauge
  Theories

abstract:
  An analysis is given of the dynamical symmetry breaking of semi-simple gauge
groups. We construct a class of renormalizable gauge theories for the
dynamically broken topcolor and technicolor interactions. It is shown that a
four-Fermi interaction in the strong coupling phase emerges by the tumbling of
semi-simple gauge groups in the low energy region. In our models the topcolor
interaction provides the top quark with a large anomalous dimension.


title: Formation of Topological Defects with Explicit Symmetry Breaking

abstract:
  We demonstrate a novel mechanism for the formation of topological defects in
a first order phase transition for theories in the presence of small explicit
symmetry breaking terms. We carry out numerical simulations of collisions of
two bubbles in 2+1 dimensions for a field theory where U(1) global symmetry is
spontaneously as well as explicitly broken. In the coalesced region of bubble
walls, field oscillations result in the decay of the coalesced portion in a
large number of defects (e.g. ten vortices and anti-vortices). We discuss the
implications of our results for axionic strings in the early Universe, for
baryon formation in quark-gluon plasma, and for electric or magnetic field.


title: Low- and High-Mass Components of the Photon Distribution Functions

abstract:
  Four new parton distributions of the photon are presented, with a description
of theory choices, properties and applications.


title: The search for nonstandard Higgs bosons at FNAL and LHC

abstract:
  We discuss the phenomenology of many Higgs doublet model - the model where
each Higgs isodoublet couples with each own quark and lepton with relatively
big Yukawa coupling constants. Namely, we discuss the discovery potential of
the Higgs bosons at LHC and find lower mass limits on nonstandard Higgs bosons
from FNAL data.


title: Quark Confinement in QCD and New Bosons

abstract:
  If the dual Meissner effect due to abelian monopole condensation is the quark
confinement mechanism of QCD as suggested in recent Monte-Carlo simulations of
lattice QCD, new axial-vector and scalar bosons with the mass of O(1GeV) would
appear as physical states which are different from ordinary hadrons and
glueballs. The axial-vector boson can not decay into ordinary color-singlet
hadrons and glueballs owing to a remainig global discrete permutation symmetry
with respect to colors (Weyl symmetry) if the vacuum respects the symmetry as
suggested from lattice MC simulations.


title:
Soft Contribution to Form Factors of $\gamma^* p \to \Delta^+$
  Transition

abstract:
  The purely nonperturbative soft contribution to the $\gamma^* p \to \Delta^+$
transition form factors is estimated using the local quark-hadron duality
approach. Our results show that the soft contribution is dominated by the
magnetic transition: the ratio $G_E^*(Q^2)/G_M^*(Q^2)$ is small for all
accessible $Q^2$, in contrast to pQCD expectations that $G_E^*(Q^2) \to
-G_M^*(Q^2)$. We also found that the soft contribution to the magnetic form
factor is large enough to explain the magnitude of existing experimental data.


title: Form Factors of Meson Decays in the Relativistic Constituent Quark Model

abstract:
  A formalism for the relativistic description of hadron decays within the
constituent quark model is presented. First, hadron amplitudes of the
light--cone constituent quark model, in particular the weak transition form
factors at spacelike momentum transfers, $q^2\le 0$, are represented in the
form of the dispersion integrals over the hadron mass. Second, the form factors
at $q^2>0$ are obtained by performing the analytic continuation from the region
$q^2<0$. As a result, the transition form factors both in the scattering and
the decay regions are expressed through the light--cone wave functions of the
initial and final hadrons. The technique is applied to the description of the
semileptonic decays of pseudoscalar mesons and direct calculation of the
transition form factors at $q^2>0$. Meson properties in the heavy quark limit
are investigated.


title: The Charm and Bottom Hyperons in a Chiral Quark Model

abstract:
  The spectrum of the C=1 hyperons is well described by the constituent quark
model, if the fine structure interaction between the light and strange quarks
is mediated by the $SU(3)_F$ octet of light pseudoscalar mesons, which are the
Goldstone bosons of the hidden approximate chiral symmetry of QCD. With the
addition of a phenomenological flavor exchange interaction of the same form
between the light and the charm quarks to describe the $\Sigma_c-\Sigma_c^*$
and $\Xi_c^s-\Xi_c^*$ splittings, the splittings between the C=1 states fall
within 10-30 MeV of the empirical values. Predictions are presented for the
lowest negative parity excited states and the magnetic moments as well.
  Corresponding predictions for the B=-1 hyperon states are also given.


title: An Extended Technicolor Model With QCD-like Symmetry Breaking

abstract:
  We present a one-doublet extended technicolor model, with all fermions in
fundamental representations. The bare lagrangian has no explicit mass terms but
generates masses through gauge symmetry breaking by purely QCD-like dynamics.
The model generates three families of quarks and leptons and can accommodate
the observed third family mass spectrum (including a large top mass and light
neutrinos). In addition, we show how the model may be extended to incorporate a
top color driven top mass without the need for a strong U(1) interaction. We
discuss the compatiblity of the model with experimental constraints and its
possible predicitive power with respect to first and second family masses.


title: An Attempt to Construct the Standard Model with Monopoles

abstract:
  We construct a model in which stable magnetic monopoles have magnetic charges
that are identical to the electric charges on leptons and quarks and the
colored monopoles are confined by strings in color singlets.