title: THE QCD VACUUM, CHIRAL PHASE TRANSITION AND QUARK-GLUON PLASMA

abstract:
  In recent years, significant progress was reached in understanding of vacuum
and hadronic structure. We review recent works on the {\it point-to-point
correlation functions}, comparing those obtained from phenomenology,
``instanton liquid" models and on the lattice. The second topic is physics of
chiral symmetry restoration, which may lead to observable hadron modification
and unusual event-per-event fluctuations. We discuss collective flow and
phenomena related with a remarkable ``softness" of the equation of state near
the phase transition, as well as phenomena at small $p_t$. We also describe
recent ideas on the mechanism of chiral restoration, based on formation of {\it
polarized instanton-antiinstanton molecules}. The third part, related to
quark-gluon plasma, is related mainly with the issue of initial equilibration
of QGP in high energy collisions. We discuss different ``parton cascade"
approaches and argue that {\it multi-gluon} processes dominate them. We briefly
discuss predictions for RHIC and LHC energies.


title:
Beyond Low-Gribov theorem for high energy interactions of scalar and
  gauge particles

abstract:
  We obtain a generalization of the Low theorem for non-Abelian boson emission
in collision of scalar and gauge vector particles and its extension to high
energy collisions for small transverse momenta of produced particles. We
demonstrate that in the case of particles with spin the direct extension the
Low formula to high energy is in contradiction with the correct amplitude
factorization behavior. Consideration of different kinematical regions and use
of methods of dual models allows us to separate contributions of intermediate
excited states and standard spin corrections in the Low formulae. We show that
the amplitude factorization occurs at high energy due to the contribution of
the intermediate states which is additional to the gluon production amplitude
for the scalar particle collision.


title: Theoretical Approach to Alignment Phenomenon

abstract:
  An explanation of the puzzling alignment effect observed in cosmic ray
experiments is suggested


title: THE SOLAR NEUTRINO PROBLEM

abstract:
  The solar neutrino problem has persisted for almost three decades. Recent
results from Kamiokande, SAGE, and GALLEX indicate a pattern of neutrino fluxes
that is very difficult to reconcile with plausible variations in standard solar
models. This situation is reviewed and suggested particle physics solutions are
discussed. A summary is given of the important physics expected from SNO,
SuperKamiokande, and other future experiments.


title: Hunting virtual LSPs at LEP200.

abstract:
  Relatively light sneutrinos, which are experimentally allowed, may
significantly affect the currently popular search strategies for supersymmetric
particles by decaying dominantly into an invisible channel. In certain cases
the second lightest neutralino may also decay invisibly leading to two extra
carriers of missing energy -- in addition to the lightest supersymmetric
particle (LSP) \zi\ -- the virtual LSPs (VLSPs). It is shown that these VLSPs
are allowed in supergravity models with common scalar and gaugino masses at the
unification scale for a sizable region of parameter space and are consistent
with all constraints derived so far from SUSY searches. The pair production of
right handed sleptons, which can very well be the lightest charged SUSY
particles in this scenario, at LEP 200 and their decay signatures are
discussed. The signal survives kinematical cuts required to remove the standard
model background. Charginos are also pair produced copiously if kinematically
accessible; they also decay dominantly into hadronically quiet di--lepton +
\etmiss\ modes leading to interesting unlike sign dilepton events which are
again easily separable from the Standard Model backgrounds at LEP 200 energies.


title: Quartic Anomalous Couplings in $\gamma\gamma$ Colliders

abstract:
  We study the constraints on the vertices $W^+W^- Z\gamma$,
$W^+W^-\gamma\gamma$, and $ZZ\gamma\gamma$ that can be obtained from
triple-gauge-boson production at the next generation of linear $e^+e^-$
colliders operating in the $\gamma\gamma$ mode. We analyze the processes
$\gamma\gamma \to W^+W^-V$ ($V=Z$, or $\gamma$) and show that these reactions
increase the potential of $e^+e^-$ machines to search for anomalous
four-gauge-boson interactions.


title: Natural Topcolor--Assisted Technicolor

abstract:
  We construct a prototype of topcolor--assisted technicolor in which, although
both top and bottom quarks acquire some mass from extended technicolor, strong
$U(1)$ couplings of technifermions are isospin symmetric and all gauge
anomalies vanish. There is a mechanism for mixing between the light and heavy
generations and there need be no very light pseudo--Goldstone bosons.


title:
LEADING VACUUM-POLARIZATION CONTRIBUTIONS TO THE RELATION BETWEEN POLE
  AND RUNNING MASSES

abstract:
  The vacuum--polarization contributions of ${\cal O}(b^{n-1} \al_s^n)$ to the
relation between the pole--mass $M$ of a quark and the \MS parameter $\mh (M)$
are evaluated by a straightforward method. They are found to approximate very
well the exact answer, known through ${\cal O}(\al_s^2)$, thus providing a
simple physical interpretation. Results are also given for the cases when the
vacuum--polarization contributions are defined by the pinch technique
prescription and specific background field gauges. Assuming that the terms $n
\geq 3$ are also dominant, we evaluate $M_t/\hat{m}_t(M_t)$, compare the
results with those of optimization methods, briefly discuss $M_b/\mh_b (M_b)$,
and estimate the irreducible errors in the perturbative series. Implications
for the electroweak amplitude $\Delta\rho$ are emphasized. An update of the QCD
corrections to this amplitude, including an estimate of the theoretical error,
is given.


title: Quark-exchange Effects in a Deuteron Breakup at Intermediate Energy

abstract:
  Microscopical approach to a deuteron breakup at high and intermediate
energies is proposed. We show that the quark exchange effects, resulting from
the full asymmetry of the $6q$-deuteron wave function with respect to the pair
permutations of quark variables, strongly affect the proton momentum
distribution in the deuteron, as well as the polarization observables of
inclusive deuteron breakup, when the ``internal momentum'' in the deuteron is
of order of a few hundreds MeV/c.


title:
A simple modification of the maximal mixing scenario for three light
  neutrinos

abstract:
  We suggest a simple modification of the maximal mixing scenario (with $S_3$
permutation symmetry) for three light neutrinos. Our neutrino mass matrix has
smaller permutation symmetry $S_{2}$ ($\nu_{\mu} \leftrightarrow \nu_{e}$), and
is consistent with all neutrino experiments except the $^{37}$Cl experiment.
The resulting mass eigenvalues for three neutrinos are $m_{1} \approx
(2.55-1.27) \times 10^{-3} eV, m_{2,3} \approx (0.71-1.43) eV$ for $\Delta
m_{LSND}^{2} = 0.5 - 2.0 eV^2$. Then these light neutrinos can account for
$\sim (2.4-4.8)% (6.2-12.4 %)$ of the dark matter for $h = 0.8 (0.5)$. Our
model predicts the $\nu_{\mu} \rightarrow \nu_{\tau}$ oscillation probability
in the range sensitive to the future experiments such as CHORUS and NOMAD.


title: Interplay of Hard and Soft Physics in Small $x$ Deep Inelastic Processes

abstract:
  Coherence phenomena, the increase with energy of coherence length and the
non-universality of parton structure of the effective Pomeron are explained.
New hard phenomena directly calculable in QCD such as diffractive
electroproduction of states with $M^2\ll Q^2$ and the color transparency
phenomenon as well as new options to measure the light-cone wave functions of
various hadrons are considered. An analogue of Bjorken scaling is predicted for
the diffractive electroproduction of $\rho$ mesons at large momentum transfers
and for the production of large rapidity gap events, as observed at HERA. A
phenomenological QCD evolution equation is suggested to calculate the basic
characteristics of the large rapidity gap events. The increase of parton
densities at small $x$ as well as new means to disentangle experimentally soft
and hard physics are considered. We discuss constraints on the increase of deep
inelastic amplitudes with $Q^2$ derived from the inconsistency of QCD
predictions for inclusive and exclusive processes and from unitarity of the S
matrix for collisions of wave packets. New ways to probe QCD physics of hard
processes at large longitudinal distances and to answer the long standing
problems on the origin of the Pomeron are suggested. Unresolved problems and
perspectives of small $x$ physics are also outlined.


title: Screening of Long-Range Leptonic Forces by Cosmic Background Neutrinos

abstract:
  The absence of dispersion effects of the SN~1987A neutrino pulse has been
used to constrain novel long-range forces between neutrinos and galactic
baryonic or non-baryonic matter. If these forces are mediated by vector bosons,
screening effects by the cosmic neutrino background invalidate the SN~1987A
limits and other related arguments.


title: Calculation of the Flux of Atmospheric Neutrinos

abstract:
  Atmospheric neutrino-fluxes are calculated over the wide energy range from 30
MeV to 3,000 GeV for the study of neutrino-physics using the data from
underground neutrino-detectors. The atmospheric muon-flux at high altitude and
at sea level is studied to calibrate the neutrino-fluxes at low energies and
high energies respectively. The agreement of our calculation with observations
is satisfactory. The uncertainty of atmospheric neutrino-fluxes is also
studied.


title: One-Loop Effects of a Heavy Higgs Boson: a Functional Approach

abstract:
  We integrate out the Higgs boson in the electroweak standard model at one
loop, assuming that it is very heavy. We construct a low-energy effective
Lagrangian, which parametrizes the one-loop effects of the heavy Higgs boson at
O(M_H^0). Instead of applying conventional diagrammatical techniques, we
integrate out the Higgs boson directly in the path integral.


title:
On the determination of double diffraction dissociation cross section at
  HERA

abstract:
  The excitation of the proton into undetected multiparticle states (double
diffraction dissociation) is an important background to single diffractive
deep-inelastic processes $ep \rightarrow e'p'\rho^{0}, ~e'p'J/\Psi, ~e'p'X$ at
HERA. We present estimates of the admixture of the double diffraction
dissociation events in all diffractive events. We find that in the $J/\Psi$
photoproduction, electroproduction of the $\rho^0$ at large $Q^2$ and
diffraction dissociation of real and virtual photons into high mass states $X$
the contamination of the double diffraction dissociation can be as large as
$\sim 30\%$, thus affecting substantially the experimental tests of the pomeron
exchange in deep inelastic scattering at HERA. We discuss a possibility of
tagging the double diffraction dissociation by neutrons observed in the forward
neutron calorimeter. We present evaluations of the spectra of neutrons and
efficiency of neutron tagging based on the experimental data for diffractive
processes in the proton-proton collisions.


title:
Radiative Corrections to $\gamma\gamma\to W^+ W^-$ in the Electroweak
  Standard Model

abstract:
  The cross-section for $\gamma\gamma\to W^+ W^-$ with arbitrary polarized
photons and W bosons is calculated within the electroweak Standard Model
including the complete virtual and soft-photonic ${\cal O}(\alpha)$
corrections. We present a detailed numerical discussion of the complete
radiative corrections and an analytical investigation of the leading
corrections. It turns out that in the on-shell renormalization scheme for fixed
$M_W$ no leading corrections associated with the running of $\alpha$ or heavy
top-quark and Higgs-boson masses occur. The corrections are typically of the
order of 10\%. They reach, however, larger values where the lowest-order
cross-sections are suppressed.


title: Fermionic decays of neutral MSSM Higgs bosons at the one-loop level

abstract:
  The results of a complete one-loop calculation for the fermionic decay width
h^0, H^0, A^0 -> f bar(f) of the neutral MSSM Higgs bosons are presented and
the dominant light Higgs decay channel h^0 -> b bar(b) is discussed in detail.
The enhancement of the partial decay width h^0 -> b bar(b) compared to the
standard Higgs decay is shown for pseudoscalar masses M_A < 300 GeV. Simpler
approximation formulae for the Higgs decays are given and their quality is
discussed by introducing an effective neutral scalar mixing angle
sin(alpha)_eff. Finally the Higgs branching ratios in b bar(b), c bar(c), tau^+
tau^- are calculated.


title: Two-loop Light Quark Corrections To The Top Width

abstract:
  A method of computing two-loop fermionic contributions to the width of a
heavy quark is described. An analytical formula for this effect in the limit of
mass of the quark much larger than the decay products is obtained for the first
time. The result confirms previous numerical studies.


title: Low-energy supersymmetry with D-term contributions to scalar masses

abstract:
  We investigate how the predictions of the Minimal Supersymmetric Standard
Model are modified by D-term contributions to soft scalar masses, which arise
whenever the rank of the gauge group at very high energies is greater than
four. We give a parameterization of the most general such contributions that
can occur when the unbroken gauge symmetry is an arbitrary subgroup of E_6, and
show how the D-term contributions leave their imprint on physics at ordinary
energies. We impose experimental constraints on the resulting parameter space
and discuss some features of the resulting supersymmetric spectrum which differ
from the predictions obtained with universal boundary conditions on scalar
masses near the Planck scale. These include relations between squark and
slepton masses; the behavior of $\sin^2 (\beta-\alpha)$ (which determines the
production cross-section for the lightest Higgs scalar boson at an e+e-
collider) and the mass of the pseudoscalar Higgs bosons; R_b [the ratio
$\Gamma(Z -> b\overline b)/\Gamma(Z -> hadrons)$; and mass differences between
charginos and neutralinos.


title: THEORETICAL SEARCH FOR COLLECTIVE EFFECTS IN MULTIPARTICLE PRODUCTION

abstract:
  The properties of QCD vacuum and the confinement of quarks and gluons
certainly influence the multiparticle production processes. Some
phenomenological attempts of the consideration of related collective effects
and the possibilities of their experimental detection are briefly discussed in
this review. We consider in particular the correlation characteristics of pion
systems, statistical and hydrodynamical analogies, the problem of phase
transition from a quark-gluon plasma to a multipion state and the possible
modifications of the evolution of the quark-gluon jets. The presentation is
somewhat simplified and could be interesting for those only entering the field.


title: Dilepton Production in High Luminosity Multi-GeV Electron Scattering

abstract:
  We consider the production of a 300GeV dilepton in very intense 4GeV electron
scattering off of a lead target. The production cross-section and angular
distribution of the resulting muons are calculated. There occur several such
events per year, and their detection is rendered feasible by measurement of
$e^+\mu^-\mu^-$ angular correlations.


title: FERMIONS IN AN EXTERNAL SU(2) MAGNETIC FIELD

abstract:
  We consider Fermions in a constant and uniform external $SU(2)$ magnetic
field. We find that the results for the energy levels depend on the choice of
gauge potential. Choosing a Landau type gauge potential yields his results. On
the other hand in another gauge potential, one obtains a different continuous
eigenvalue spectrum.


title: SEARCHING FOR HIGGS BOSONS ON LHC USING $b$-TAGGING

abstract:
  We demonstrate that the detection of the SM and MSSM Higgs bosons will be
possible at the LHC via $t\anti t b\anti b$ and $b\anti b b\anti b$ final
state, provided $b$-tagging can be performed with good efficiency and purity.


title:
Experimental momentum spectra of identified hadrons at $e^+e^-$
  colliders compared to QCD calculations

abstract:
  Experimental data on the shape of hadronic momentum spectra are compared to
theoretical predictions in the context of calculations in the Modified Leading
Log Approximation (MLLA), under the assumption of Local Parton Hadron Duality
(LPHD).
  Considered are experimental measurements at $e^+e^-$-colliders of $\xi_p^*$,
the position of the maximum in the distribution of $\xi_p=\log(1/x_p)$, where
$x_p=p/p_{beam}$. The parameter $\xi_p^*$ is determined for various hadrons at
various centre of mass energies. The dependence on the hadron type poses some
interesting questions about the process of hadron-formation. The dependence of
$\xi^*_p$ on the centre of mass energy is seen to be described adequately by
perturbation theory. A quantitative check of LPHD + MLLA is possible by
extracting a value of $\alpha_s$ from an overall fit to the scaling behaviour
of $\xi^*_p$.


title:
Effective Potential Improvements, $\epsilon$-expansions, and the
  Electroweak Phase Transition

abstract:
  Two recently proposed approaches to the study of the electroweak phase
transition are discussed.


title:
SO(10): a possible Scenario for new Physics in the Neutrino Sector and
  Baryogenesis

abstract:
  The implications on neutrino physics and on the dynamical generation of the
baryonic asymmetry of a class of $SO(10)$ non-supersymmetric models are
discussed.


title: Optimized Top Quark Analysis with the Decision Tree

abstract:
  We present an optimized and physically motivated method for separating top
quark signal events from background events at the Tevatron. For the top quark
signal $t\bar t \to e/\mu + 4$ jets, we show how to reject all but $25\%$ of
the background in a data sample while retaining $80\%$ of the signal, without
introducing bias into the subsequent mass measurement. The technique used is
the Binary Decision Tree. Combining this highly efficient procedure for signal
identification with a novel algorithm for top quark reconstruction, we propose
a powerful new way to measure the top quark mass.


title:
Anomaly-Free Gauged $U(1)'$ in Local Supersymmetry and Baryon-Number
  Violation

abstract:
  The supersymmetric extension of the standard model suffers from a problem of
baryon-number violation. Discrete (and global) symmetries introduced to protect
the proton are unstable under gravitational effects. We add a gauged $U(1)_X$
to the standard model gauge group $G_{SM}$ and require it to be anomaly-free.
As new (chiral) superfields we only allow $G_{SM}$-singlets in order to
maintain the good unification predictions. We find the most general set of
solutions for the rational singlet charges. We embed our models in {\it local}
supersymmetry and study the breaking of supersymmetry and $U(1)_X$ to determine
$M_X$. We determine the full non-renormalizable and gauge invariant Lagrangian
for the different solutions. We expect any effective theory to contain baryon-
and lepton-number violating terms of dimension four suppressed by powers of
$M_X/M_{Pl}$. The power is predicted by the $U(1)_X$ charges. We find
consistency with the experimental bounds on the proton lifetime and on the
neutrino masses. We also expect all supersymmetric models to have an unstable
but longlived lightest supersymmetric particle. Consistency with underground
experiments on upward going muons leads to stricter constraints than the proton
decay experiments. These are barely satisfied.


title:
Analytic Approach to the MSSM Mass Spectrum in the Large Tan$\beta$
  Regime

abstract:
  In various unified extensions of the Minimal Supersymmetric Standard Model,
the Yukawa couplings of the third generation are predicted to be of the same
order. As a result, low energy measured mass ratios, require large ratios of
the standard model Higgs vacuum expectation values, corresponding to a large
value of the parameter $tan\beta$. We present analytic solutions for the Yukawa
couplings and the Higgs and third generation squark masses, in the case of
large top and bottom Yukawa couplings. We examine regions of these Yukawas
which give predictions for the top mass compatible with the present
experimentally determined top mass and provide useful approximate formulae for
the scalars. We discuss the implications on the Radiative Symmetry Breaking
mechanism and derive constraints on the undetermined initial conditions of the
scalars.


title:
SEMILEPTONIC LEPTON-NUMBER/FLAVOUR-VIOLATING tau DECAYS IN MAJORANA
  NEUTRINO MODELS

abstract:
  Motivated by the recent investigation of neutrinoless $\tau$-lepton decays by
the CLEO collaboration, we perform a systematic analysis of such decays in a
possible new-physics scenario with heavy Dirac/Majorana neutrinos, including
heavy-neutrino nondecoupling effects, finite quark masses, and quark as well as
meson mixings. We find that $\tau$-lepton decays into an electron or muon and a
pseudoscalar or vector meson can have branching ratios close to the
experimental sensitivity. Numerical estimates show that the predominant decay
modes of this kind are $\tau^-\to e^-\phi$, $\tau^-\to e^-\rho^0$, and
$\tau^-\to e^-\pi^0$, with branching ratios of order $10^{-6}$.


title: Bound States and Instabilities of Vortices

abstract:
  We examine the spectrum of small perturbations around global and local
(gauge) abelian vortices, using simple numerical matrix techniques. The results
are of interest for both cosmic strings and for their condensed matter
analogues, superfluid and superconducting vortices. We tabulate the
instabilities of higher winding number vortices, and find several bound states.
These localised oscillations of the order parameter can be thought of as
particle states trapped in the core of the string.


title: Probing for Ultraheavy Quanta at LHC

abstract:
  Experiments at the LHC are sensitive to the presence or absence of matter
quanta at mass scales far beyond the scales they can probe directly. The
production of $Z$ boson pairs by gluon-gluon fusion is greatly enhanced if
there are ultraheavy quanta that carry $SU(3)_{\rm Color}$ and get their mass
from electroweak symmetry breaking. For example, a fourth generation quark
doublet with an arbitrarily heavy mass would induce a large excess in the $ZZ$
yield that could be detected at the LHC with only $\simeq 10\%$ of the design
luminosity.


title: The Polarization of a QED Plasma in a Strong Magnetic Field

abstract:
  In this paper we study the polarization tensor of photons in a QED plasma in
the presence of a magnetic field. We do it both at vanishing and at finite
temperature. We use two different methods to compute the polarization tensor
components $\Pi^{\mu\nu}$ within the one-loop approximation. The first starts
from the effective Lagrangian of the system and relates $\Pi^{\mu\nu}$ to the
thermodynamic quantities. The second makes use of the electron propagator in an
external magnetic field. In this second approach we use an imaginary time
formalism. These methods give consistent results in the first non-vanishing
order in the photon 4-momentum. Beyond this limit the first method is not
applicable and the introduction of the second can not be avoided. We give some
physical interpretations of our results.


title:
INSTABILITY OF A NIELSEN-OLESEN VORTEX EMBEDDED IN THE ELECTROWEAK
  THEORY: II. ELECTROWEAK VORTICES AND GAUGE EQUIVALENCE

abstract:
  Vortex configurations in the electroweak gauge theory are investigated. Two
gauge-inequivalent solutions of the field equations, the Z and W vortices, have
previously been found. They correspond to embeddings of the abelian
Nielsen-Olesen vortex solution into a U(1) subgroup of SU(2)xU(1). It is shown
here that any electroweak vortex solution can be mapped into a solution of the
same energy with a vanishing upper component of the Higgs field. The
correspondence is a gauge equivalence for all vortex solutions except those for
which the winding numbers of the upper and lower Higgs components add to zero.
This class of solutions, which includes the W vortex, instead corresponds to a
singular solution in the one-component gauge. The results, combined with
numerical investigations, provide an argument against the existence of other
vortex solutions in the gauge-Higgs sector of the Standard Model.


title: Polarized Heavy Quarks

abstract:
  Polarization studies for heavy quarks can lead to important tests of the
Standard Model. Top quark pair production in $e^+e^-$ annihilation is
considered near energy threshold. It is shown that for longitudinally polarized
electrons the produced top quarks and antiquarks are highly polarized.
Dynamical effects originating from strong interactions in the $t-\bar t$ system
can be calculated using Green function method. Energy-angular distributions of
leptons in semileptonic decays of polarized heavy quarks are sensitive to both
the polarization of the decaying quark and V-A structure of the weak charged
current. Some applications to $b$ quark physics at the $Z^0$ resonance are
briefly reviewed.


title: Quark Matter in the Chiral Color Dielectric Model

abstract:
  We study the equation of state (EOS) of quark matter at zero temperature,
using the Color Dielectric Model (CDM) to describe confinement. Sensible
results are obtained in the version of the CDM for which confinement is imposed
{\it smoothly}. The two--phases version of the model turns out to give
unrealistic results for the EOS. Chiral symmetry plays a marginal r\^ole and
the quarks are massive till high densities. The deconfinement phase transition
is smooth and unlikely to be first order. Instabilities of the quark matter and
the gap equation are discussed.


title: Hadronic Light-by-light Scattering Effect on Muon g-2

abstract:
  The hadronic light-by-light scattering contribution to muon $g-2$ is examined
using low energy effective theories of QCD, the Nambu-Jona-Lasinio model and
hidden local chiral symmetry, as guides. Our result is $- 36 \times 10^{-11}$
with an uncertainty of $\pm 16 \times 10^{-11}$, which includes our best
estimate of model dependence. This is within the expected measurement
uncertainty of $40\times 10^{-11}$ in the forthcoming experiment at Brookhaven
National Laboratory. Our result removes one of the main theoretical obstacles
in verifying the existence of the weak contribution to the muon $g-2$.


title:
Pion and Kaon Production in $e^+e^-$ and $ep$ Collisions at
  Next-to-Leading Order

abstract:
  We present new sets of fragmentation functions for charged pions and kaons,
both at leading and next-to-leading order. They are fitted to data on inclusive
charged-hadron production in $e^+e^-$ annihilation taken by TPC at PEP ($\sqrt
s=29$~GeV) and to similar data by ALEPH at LEP, who discriminated between
events with charm, bottom, and light- flavour fragmentation in their
charged-hadron sample. We treat all partons independently and to properly
incorporate the charm and bottom thresholds. Due to the sizeable energy gap
between PEP and LEP, we are sensitive to the scaling violation in the
fragmentation process, which allows us to extract a value for the asymptotic
scale parameter of QCD, $\Lambda$. Recent data on inclusive charged-hadron
production in tagged three-jet events by OPAL and similar data for longitudinal
electron polarization by ALEPH allow us to pin down the gluon fragmentation
functions. Our new fragmentation functions lead to an excellent description of
a multitude of other $e^+e^-$ data on inclusive charged-hadron production,
ranging from $\sqrt s=5.2$~GeV to LEP energy. In addition, they agree nicely
with the transverse-momentum spectra of single charged hadrons measured by H1
and ZEUS in photoproduction at the $ep$ collider HERA, which represents a
nontrivial check of the factorization theorem of the QCD-improved parton model.


title: An update on $\chi_c$ Decays: Perturbative QCD versus Data

abstract:
  We present a global fit of current available experimental results on $\chi_c$
decays within next-to-leading-order perturbative QCD. The quality and reduced
errors of recent data improve the agreement between theory and experiment.


title: TAU-PAIR PRODUCTION VIA PHOTON-PHOTON COLLISIONS AT LEP

abstract:
  We point out that the cross-section for the process $e^+ e^- \to e^+ e^-
\tau^+ \tau^-$ at LEP is large enough to allow for a study of the anomalous
electromagnetic couplings of the $\tau$ lepton. We show that the present bounds
on the magnetic dipole moment can be improved and that competitive bounds can
be obtained for the electric dipole moment using the data taken from 1992 to
1994. Finally, we briefly discuss the improvements that can be obtained at LEP
II.


title: Instanton size distribution: repulsion or the infrared fixed point?

abstract:
  We discuss available information about the instanton size distribution
$d(\rho)$, which comes from lattice simulations and the interacting instanton
liquid model. Not only they are remarkably consistent, but one can also
reproduce $d(\rho)$ with an alternative idea, based on the infrared fixed
point. We show, that lattice non-perturbative beta-function (for $bare$ charge
renormalization) also suggests such a hint. We also discuss whether it is
possible to reconcile the instanton physics with reasonable
large-number-of-colors limit, concluding that our fits for SU(2) and SU(3)
theories are actually very close to the critical value $8\pi^2/g^2= N_c*5.4$
when it is the case.


title:
Electric dipole moment of neutron in the Kobayashi-Maskawa model with
  four generations of quarks

abstract:
  We show that the existence of a possible fourth heavy generation of quarks
gives rise to a significant enhancement to the neutron electric dipole moment
in comparison with the Standard Model prediction. The smaller degree of
suppression in this case is linked to the presence of the operators of
dimension $\leq$ 6 which enter into the effective Lagrangian with coefficients
proportional to the square of the top quark mass. Numerically, the enhancement
is mainly associated with chromoelectric dipole moment of the s quark which
appears at three loop level, of the order $\al_s\al_w^2m_sm_t^2/m^4_w$ from the
CP-odd combination of mixing angles between second, third and fourth
generations. Its value is calculated explicitly in the limit of large masses of
the fourth generation of quarks. The corresponding contribution to the electric
dipole moment of the neutron is $5\cdot10^{-30} e\cdot cm$ in the most
optimistic scenarios about the values of the Kobayashi-Maskawa matrix elements.
The additive renormalization of $\theta$-term in this model is estimated as
$10^{-13}$.


title: Finite-Temperature Corrections in the Dilated Chiral Quark Model

abstract:
  We calculate the finite-temperature corrections in the dilated chiral quark
model using the effective potential formalism. Assuming that the dilaton limit
is applicable at some short length scale, we interpret the results to represent
the behavior of hadrons in dense {\it and} hot matter. We obtain the scaling
law, $\frac{f_{\pi}(T)}{f_{\pi}} = \frac{m_Q (T)}{m_Q}
  \simeq \frac{m_{\sigma}(T)}{m_{\sigma}}$ while we argue, using PCAC, that
pion mass does not scale within the temperature range involved in our
Lagrangian. It is found that the hadron masses and the pion decay constant drop
faster with temperature in the dilated chiral quark model than in the
conventional linear sigma model that does not take into account the QCD scale
anomaly. We attribute the difference in scaling in heat bath to the effect of
baryonic medium on thermal properties of the hadrons. Our finding would imply
that the AGS experiments (dense {\it and} hot matter) and the RHIC experiments
(hot and dilute matter) will ``see" different hadron properties in the
hadronization phase.


title: On a subtle point of sum rules calculations: toy model

abstract:
  We consider a two-point correlator in massless $\phi^3$ model within the
ladder approximation . The spectral density of the correlator is known
explicitly and does not contain any resonances. Meanwhile making use of the
standard sum rules technique with a simple "resonance + continuum" model of the
spectrum allows to predict parameters of the "resonance" very accurately in the
sense that all necessary criteria of stability are perfectly satisfied.


title: On the width of molecular states

abstract:
  Width of molecular-type $Q\bar{Q}q\bar{q}$ hadronic states is discussed. It
depends on the quantum numbers of the state and on the details of the
long-range mechanism ensuring the bindedness of a molecule. Specific cases when
the width is large are considered in detail.


title: Bounds on $\Delta B=1$ Couplings in the Supersymmetric Standard Model

abstract:
  The most general supersymmetric model contains baryon number violating terms
of the form $\lm_{ijk}\ \ov{D}_i\ \ov{D}_j\ \ov{U}_k$ in the superpotential. We
reconsider the bounds on these couplings, assuming that lepton number
conservation ensures proton stability. These operators can mediate $n-\ov{n}$
oscillations and double nucleon decay. We show that neutron oscillations do
not, as previously claimed, constrain the $\lm_{dsu}$ coupling; they do provide
a bound on the $\lm_{dbu}$ coupling, which we calculate. We find that the best
bound on $\lm_{dsu}$ arises from double nucleon decay into two kaons. There are
no published limits on this process; experimenters are urged to examine this
nuclear decay mode. Finally, the other couplings can be bounded by the
requirement of perturbative unification.


title: Quark structure of the pion and pion form factor

abstract:
  We consider the pion structure in the region of low and moderately high
momentum transfers: at low $Q^2$, the pion is treated as a composite system of
constituent quarks; at moderately high momentum transfers,
$Q^2=10\div25\;GeV^2$, the pion \ff is calculated within perturbative QCD
taking into account one--gluon hard exchange. Using the data on pion \ff at
$Q^2<3\;GeV^2$ and pion axial--vector decay constant, we reconstruct the pion
\wf in the soft and intermediate regions. This very wave function combined with
one--gluon hard scattering amplitude allows a calculation of the pion \ff in
the hard region $Q^2=10\div25\;GeV^2$. A specific feature of the reconstructed
pion \wf is a quasi--zone character of the $q\bar q$--excitations. On the basis
of the obtained pion \wf and the data on deep inelastic scattering off the
pion, the valence quark distribution in a constituent quark is determined.


title: Tau Decays into Kaons

abstract:
  Predictions for semi-leptonic decay rates of the tau lepton into two and
three meson final states with one or two kaons are derived, including a
discussion of K_S pi- K_S, K_L pi- K_L and K_S pi- K_L. The hadronic matrix
elements are expressed in terms of form factors, which can be predicted by
chiral Lagrangians supplemented by informations about all possible low-lying
resonances in the different channels. Isospin symmetry relations among the
different final states are carefully taken into account. The calculated
branching ratios are compared with measured decay rates where data are
available.


title:
Can a Highly Virtual Nucleon Experience Final State Interactions in
  Electron-Nucleus Scattering?

abstract:
  We discuss how the virtuality of the struck particle may affect the final
state interactions in electron-nucleus scattering. The extent to which short
range correlations inhibit rescattering taking place within the range of the
repulsive core of the NN interaction is quantitatively analyzed. The possible
modifications of the nucleon-nucleon scattering amplitude associated with the
virtuality is also studied, within the framework of a nonrelativistic model.
The results suggest that the on shell approximation can be safely employed in
the kinematical region relevant to the analysis of the available inclusive data
at large momentum transfer and low energy loss.


title: Transverse momentum distribution in hadrons. What can we learn from QCD?

abstract:
  We discuss some QCD constraints on light-cone $\pi$ meson wave function
$\psi(\k, x)$ . The analysis is based on such general methods as dispersion
relations, duality and PCAC. We calculate the asymptotical behavior of the wave
function ($wf$) at the end-point region ($x\to 1$ and $\k\to\infty$) by
analysing the corresponding large $n-$th moments in transverse
$\la\vec{k}_{\perp}^{2n}\ra \sim n!$ and longitudinal $\la (2x-1)^n\ra \sim
1/n^2$ directions. This information fixes the asymptotic behavior of $wf$ at
large $\k$ (which is turned out to be Gaussian commonly used in the
phenomenological analyses). We discuss one particular application of the
obtained results. We calculate the nonleading "soft" contribution to the pion
form factor at intermediate momentum transfer. We argue, that due to the
specific properties of $\psi(\k, x)$, the corresponding contribution can
temporarily {\bf simulate} the leading twist behavior in the extent region of $
Q^2:~~3 GeV^2\leq Q^2\leq 40 GeV^2 $, where $Q^2 F(Q^2)\sim const.$ Such a
mechanism, if it is correct, would be an explanation of the phenomenological
success of the dimensional counting rules at available, very modest energies
for many different processes. We discuss some inclusive amplitudes (like Drell
Yan and Deep Inelastic) where intrinsic $\pi$ meson structure might be
essential. The relation to the valence quark model is also discussed.


title: On the instantaneous Bethe-Salpeter equation

abstract:
  We present a systematic algebraic and numerical investigation of the
instantaneous Bethe-Salpeter equation. Emphasis is placed on confining
interaction kernels of the Lorentz scalar, time component vector, and full
vector types. We explore stability of the solutions and Regge behavior for each
of these interactions, and conclude that only time component vector confinement
leads to normal Regge structure and stable solutions.


title:
Consequences of Recent Electroweak Data and W-mass for the Top Quark and
  Higgs Masses

abstract:
  We critically reexamine the precision tests of the standard model by coupling
the current world average value of $M_W$ with the recent LEP electroweak data
with the aid of a modified ZFITTER program to include the dominant two-loop and
QCD-EW mixed terms. The results show a clear evidence of nonvanishing
electroweak radiative corrections. The recent CDF $m_t$ is a solution of the
minimal $\chi^2$-fits to the recent LEP data set and $M_W=80.23(18)~$ GeV but
with a heavy Higgs scalar, i.e., $m_t=179~$ GeV and $m_H=300~$ GeV. We discuss
how sensitive $m_t$ and $m_H$ are depending on the exact value of $M_W$ even
within the present uncertainty, as well as on $\alpha_s$ and $\alpha (M_Z)$. We
show how the future improvements on $M_W$ can discriminate different values of
$m_t$ and $m_H$ from the electroweak data and provide a crucial and decisive
test for the standard model.


title: LOW ENERGY SUPERSYMMETRY PHENOMENOLOGY

abstract:
  We summarize the current status and future prospects for low energy (weak
scale) supersymmetry. In particular, we evaluate the capabilities of various
$e^+e^-$, $p\bar p$ and $pp$ colliders to discover evidence for supersymmetric
particles. Furthermore, assuming supersymmetry is discovered, we discuss
capabilities of future facilities to dis-entangle the anticipated spectrum of
super-particles, and, via precision measurements, to test mass and coupling
parameters for comparison with various theoretical expectations. We comment
upon the complementarity of proposed hadron and $e^+e^-$ machines for a
comprehensive study of low energy supersymmetry.


title: Chiral Effective Lagrangian Description of Bulk Nuclear Matter

abstract:
  Here we point out that the four-nucleon terms incorporate into lowest order
non-linear chiral effective Lagrangians the same description of bulk nuclear
matter contained in the Walecka model, that is generally considered
satisfactory. We find this point worth noticing because, while the Walecka
model is an entirely phenomenological renormalizable model, non-linear chiral
Lagrangians have a deep basis in elementary particle physics, and, in this
sense, are more fundamental.


title: Neutrino mass and mirror universe

abstract:
  The existence of the mirror world, with the same microphysics as our own one
but with opposite P-asymmetry, not only restores an exact equivalence between
left and right but also naturally explains, via a see-saw like mechanism, why
the neutrino is ultralight.


title:
A System for the Automatic Computation of Cross-Sections Including SUSY
  Particles

abstract:
  We introduce a new method to treat Majorana fermions on the GRACE system,
which has already been developed for the computation of the matrix elements for
the processes of the standard model. In the standard model, we already have
included such particles as Dirac fermions, gauge bosons and scalar bosons in
the system. On the other hand, there are four Majorana fermions called
neutralinos in the minimal SUSY standard model (MSSM). In consequence, we have
constructed a system for the automatic computation of cross-sections for the
processes of the MSSM. It is remarkable that our system is also applicable for
another model including Majorana fermions once the definition of the model file
is given.


title: SUBCRITICAL BUBBLES NEAR THE PHASE SPACE DOMAIN WALL

abstract:
  We study the subcritical bubble formation near the phase space domain wall.
We take into account that the phase of the scalar field can vary using complex
U(1) symmetric field and a phenomenological potential with cubic term
responsible to symmetry breaking. We show that the presence of the domain wall
induces subcritical bubbles so that their formation rate near the wall is
considerably larger than far of it. The allowed deviations of the phases of new
bubbles are so large that they prevent the system from induced nucleation.


title: Heavy-quark correlations in deep-inelastic electroproduction

abstract:
  We have completed the next-to-leading order perturbative QCD corrections to
the virtual-photon exclusive differential cross sections for heavy quark
production in deep-inelastic electron-proton scattering, i.e. $e + P
\rightarrow Q + \overline{Q} + X$. Using these results, we have computed
distributions which are sensitive to correlations among the heavy quark, the
heavy antiquark, and the associated jet. Some predictions for charm and bottom
heavy quark production at the electron-proton collider HERA are presented.


title: Theory of Rare B Decays

abstract:
  Theoretical aspects of rare $B$ decays are reviewed. The focus is on the
relation between short-distance interactions and physical observables. It is
argued that there remain significant uncertainties in the theoretical treatment
of certain important quantities. (Talk presented at the International Symposium
on Vector Boson Interactions, University of California, Los Angeles, February
1-3, 1995)


title: Semileptonic Meson Decays in the Quark Model: An Update

abstract:
  We present the predictions of ISGW2, an update of the ISGW quark model for
semileptonic meson decays. The updated model incorporates a number of features
which should make it more reliable, including the constraints imposed by Heavy
Quark Symmetry, hyperfine distortions of wavefunctions, and form factors with
more realistic high recoil behaviors.


title: SUPERSYMMETRIC PHENOMENOLOGY IN THE LIGHT OF GRAND UNIFICATION

abstract:
  I review some aspects of supersymmetric grand unification and emphasize a
recent development in the area of gauge coupling unification.


title: Fermion Masses, Mixing Angles and Supersymmetric SO(10) Unification

abstract:
  We reanalyse the problem of fermion masses in supersymmetric SO(10) grand
unified models. In the minimal model, both low energy Higgs doublets belong to
the same {\bf{10}} representation of SO(10) implying the unification not only
of the gauge but also of the third generation Yukawa couplings. These models
predict large values of $\tan\beta \sim 50$. In this paper we study the effects
of departing from the minimal conditions in order to see if we can find models
with a reduced value of $\tan\beta$. In order to maintain predictability,
however, we try to do this with the addition of only one new parameter. We
still assume that the fermion masses arise from interactions of the spinor
representations with a single ${\bf 10}$ representation, but this ${\bf 10}$
now only contains a part of the two light Higgs doublets. This enables us to
introduce one new parameter $\omega=\lambda_b/\lambda_t$. For values of $\omega
\ll 1$ we can in principle reduce the value of $\tan\beta$. In fact, $\omega$
is an overall factor which multiplies the down quark and charged lepton Yukawa
matrices. Thus the theory is still highly constrained. We show that the first
generation quark masses and the CP-violation parameter $\epsilon_K$ yield
strong constraints on the phenomenologically allowed models. In the end, we
find that large values of $\tan\beta$ are still preferred.


title:
Heavy-Quark Production by Polarized and Unpolarized Photons in
  Next-to-Leading Order

abstract:
  Complete analytical results for the production of heavy-quark pairs by
polarized and unpolarized photons in next-to-leading order are presented. Two-,
three- and two plus three-jet cross sections for total photon spin $J_z=0,\pm
2$ are presented for $b\bar{b}(g)$ production. The 2-jet cross sections are
considered as a background to $\gamma\gamma\rightarrow H^* \rightarrow
b\bar{b}$ (standard model). Top production, not too far above threshold, is
also considered for $J_z=0,\pm 2$. For both $b$- and $t$-quark production, the
higher order QCD corrections are found to be significant.


title:
Testing the $\Delta S=\Delta Q$ Rule with Exclusive Semi-Leptonic Kaon
  Decays

abstract:
  We consider the possibility of violations of the selection rule $\Delta
S=\Delta Q$ at an appreciable level in {\it exclusive} semi-leptonic decays of
Kaons. At $\Phi$-Factories, intense Kaon beams will be available and will probe
among others, the semi-leptonic decays $K_{l4}$ and $K_{l3\gamma}$ in addition
to $K_{l3}$ and could provide novel testing grounds for the $\Delta S=\Delta Q$
rule. In particular, the branching ratio of $K_{l3\gamma}$ is non-negligible
and could be used to probe new phenomena associated with the violation of this
selection rule. Furthermore, we modify certain di-lepton event rate ratios and
asymmetries and time asymmetries that have been constructed by Dass and Sarma
for di-lepton events from Beon decays to test the $\Delta B=\Delta Q$ at the
$\Upsilon (4S)$, to the Kaon system at the $\phi(1020)$. We find that the large
width of the $K_S$ relative to that of $K_L$ plays an important role in
enhancing some of the time asymmetries.


title: Perturbative predictions for B_c meson production in hadronic collisions

abstract:
  Perturbative cross section for direct B_c meson production in gluon gluon
scattering g g --> B_c^+ b \bar{c} is calculated and compared with other
existing results. Predictions for hadronic B_c production at Tevatron and LHC
are presented and the main sources of uncertainties are discussed.


title:
Resummation of Running Coupling Effects in Semileptonic B Meson Decays
  and Extraction of $|V_{cb}|$

abstract:
  We present a determination of $|V_{cb}|$ from semileptonic B decays that
includes resummation of supposedly large perturbative corrections, originating
from the running of the strong coupling. We argue that the low value of the BLM
scale found previously for inclusive decays is a manifestation of the
renormalon divergence of the perturbative series starting already in third
order. A reliable determination of $|V_{cb}|$ from inclusive decays is possible
if one either uses a short-distance b quark mass or eliminates all unphysical
mass parameters in terms of measured observables, such that all infra-red
contributions of order $1/m_b$ cancel explicitly. We find that using the
$\overline{\rm MS}$ running mass significantly reduces the perturbative
coefficients already in low orders. For a semileptonic branching ratio of
$10.9\%$ we obtain $|V_{cb}|(\tau_B/1.50\,{\rm ps})^{1/2}= 0.041\pm 0.002$ from
inclusive decays, in good agreement with the value extracted from exclusive
decays.


title: Experimental Signatures of a Parity Violating Anomalous Coupling $g_5^Z$

abstract:
  I discuss the experimental signatures of a parity violating but CP conserving
interaction in the symmetry breaking sector of the electroweak theory.


title: Bose-Einstein Correlations for Expanding Finite Systems

abstract:
  There are two length-scales present simultaneously in all the principal
directions for three-dimensionally expanding, finite systems. These are
discussed in detail for the case of a longitudinally expanding system with a
transverse flow and a transverse temperature profile. For systems with large
geometrical sizes we find an $m_t$-scaling for the parameters of the
Bose-Einstein correlation function, which may be valid in the whole transverse
mass region for certain model parameters. In this limit, the Bose-Einstein
correlations view only a small part of the source. The large geometrical sizes
can be inferred from a simultaneous analysis of the invariant momentum
distribution and the Bose-Einstein correlation function. A preliminary analysis
of the NA44 data indicates that instead of a small fireball we are observing a
big and expanding snowball in $S + Pb $ reactions at CERN SPS energies.


title: Chiral Charge Flux and Electroweak Baryogenesis

abstract:
  By treating CP-violating interaction of the electroweak bubble wall as a
perturbative term, chiral charge flux through the bubble wall is estimated. It
is found that the absolute value of the flux $F_Q$ has a sharp peak at $m_0
\sim a \sim T$ with $F_Q/(u T^3) \sim 10^{-3}\, (Q_L-Q_R)\,\Delta \theta$. Here
$m_0$ is the fermion mass, $1/a$ is the wall thickness, $T$ is the temperature
at which the bubbles are growing, $u$ is the wall velocity, $Q_{L(R)}$ is the
chiral charge of the relevant left(right)-handed fermion and $\Delta\theta$ is
the measure of CP violation.


title: Phase Transition in the Early Universe and Charge Quantisation

abstract:
  It is shown, for the first time , that surprisingly the electric charge loses
all physical meaning above the electro-weak phase transition temperature.
Implications of this discovery in the context of the early universe within the
framework of various unified models are discussed.


title:
About Composite Scalar Representations of the Electroweak Symmetry Group
  of the Standard Model

abstract:
  The scalar composite representations of the electroweak symmetry group of the
Standard Model are exhibited in the case of two generations of quarks. The link
between `strong' and `electroweak' eigenstates is investigated, showing that
the quark content commonly attributed to pseudoscalar mesons needs to be
modified. After doing so, the mechanism suppressing the decays K{+} into Pi{+}
Pi{0} with respect to K{short} into Pi{+} Pi{-} is unraveled, without reference
to any model of quark spectator or `factorization' hypothesis. The same
mechanism is shown to suppress the decays K{long} into two pions. Leptonic and
semi-leptonic decays are also studied. The mass relations between`electroweak'
eigenstates, verified at better than one percent, mass(Pi{3})/mass(Pi{+}) =
cos(theta Cabibbo) = mass(chi{1910})/mass(Ds) are obtained.


title: ANOMALOUS EVOLUTION EFFECTS ON SINGLET STRUCTURE FUNCTIONS

abstract:
  A study of the effects of the anomalous evolution due to mesonic degrees of
freedom on singlet structure functions is presented. Possible phenomenological
applications are discussed.


title: Strange Hadrons from the ALCOR Rehadronization Model

abstract:
  Hadron multiplicities --- especially for strange particles --- are calculated
in the framework of the algebraic coalescence rehadronization model (ALCOR),
which counts for redistribution of quarks into hadrons for relativistic
heavy-ion collisions. The influence of Bjorken flow on the final hadronic
composition are incorporated in the model. A comparison is made with the CERN
SPS NA35 $S+S$ and $p+p$ experiments. The analysis of these experiments with
ALCOR shows a strangeness enhancement for S+S collisions and a possible
formation of a sort of semi-deconfined state of the matter. Predictions for
Pb+Pb collisions (NA49) are also presented.


title: Higgs production in $e^+ e^- \to l{\bar l} q{\bar q}$ at LEP and NLC

abstract:
  Predictions for Higgs production with processes of the type $e^+ e^-
\rightarrow \mu{\bar \mu}\;b\bar b $ at LEP~2 and the NLC are calculated. Short
analytical formulae describe the double differential distribution in the
invariant masses of the $\mu \bar \mu$ and $b \bar{b}$ pairs. The total cross
section may be got with two numerical integrations. The various
Higgs-background interferences vanish either identically or are small. The
background contributions depend strongly on cuts applied on the invariant
masses.


title:
Neutrino-induced Muon Fluxes from Neutralino Annihilations in the Sun
  and in the Earth

abstract:
  The flux of neutrino-induced muons at the surface of the Earth is calculated
from injection of neutralino annihilation products in the core of the Sun and
the Earth. An improved treatment of neutrino propagation through the Sun is
performed and the results are presented in an easy-to-use parameterization. For
an explicit supersymmetric model, an observable neutralino annihilation signal
is demonstrated.


title: Summary talk: Gauge Boson Self Interactions

abstract:
  A review is given of the theoretical expectations of the self couplings of
gauge bosons and of the present experimental information on the couplings. The
possibilities for future measurements are also discussed.


title: NON-POLYNOMIAL LAGRANGIANS IN THE SKYRME MODEL

abstract:
  We choose three different coupling constants for a particular
higher-derivative term in the Skyrme model that allows the total Lagrangian to
converge in a binomial, geometric and a logarithmic form. Improved numerical
results are obtained.


title: Symmetries at ultrahigh energies and searches for neutrino oscillations

abstract:
  Motivated by the possibility that new (gauge) symmetries which are broken at
the grand- (string-) unification scale give rise to texture zeros in the
fermion mass matrices which are at the origin of the hierarchy of masses and
mixings we explore the effect of such zeros on the neutrino spectrum of
SUSY-GUT models. We find that the quadratic-seesaw spectrum on which most
expectations are focused is neither the only nor the most interesting
possibility. Cases of strong $\nu_{\mu} - \nu_{\tau}$ or $\nu_e - \nu_{\tau}$
mixing are present for a specific texture structure of the Yukawa matrices and
experimental evidence can thus throw some light on the latter. In contrast if
the quadratic-seesaw scenario should be confirmed very little could be said
about the symmetries of the Yukawa sector.


title: Looking for CP Violation in W Production and Decay

abstract:
  We describe CP violating observables in resonant $W^\pm$ and $W^\pm$ plus one
jet production at the Tevatron. We present simple examples of CP violating
effective operators, consistent with the symmetries of the Standard Model,
which would give rise to these observables. We find that CP violating effects
coming from new physics at the $TeV$ scale could in principle be observable at
the Tevatron with $10^6$ $W^\pm$ decays.


title: NEW PARTICLES AND INTERACTIONS

abstract:
  We analyze the manifestations of new matter particles predicted by models of
new physics beyond the Standard Model, at present and future high--energy
colliders. We consider both the production of these new particles and some of
their indirect signatures at $pp$ and $eP$ colliders as well as TeV $\ee$
colliders with their $\ee, e \gamma, \gamma \gamma$ and $e^- e^-$ modes. The
report is arranged into four main sections plus an overview. These sections
will deal separately with exotic and excited fermions, difermions, and new
interactions.


title: SEARCHING FOR NEW MATTER PARTICLES AT FUTURE COLLIDERS

abstract:
  We discuss the production of new matter particles that are predicted by many
extensions of the Standard Model, at future high--energy pp, eP and $e^+e^-$
linear colliders. We focus on the case of exotic, excited and di--fermions.
Talk given at "Beyond the Standard Model IV", Lake Tahoe, Ca., December 1994.


title: Production of Supersymmetric Higgs Bosons at LEP x LHC

abstract:
  Within the Minimal Supersymmetric Standard Model (MSSM), we study the
production of the neutral scalar and pseudoscalar as well as the charged Higgs
bosons together with fermions or sfermions in deep inelastic $ep$ scattering at
$\sqrt{s}=1.6$ TeV. We focus on the parameter space where a Higgs particle is
likely to be invisible at LEP2 and LHC. Although we choose gaugino/higgsino
mixing scenarios that maximize the corresponding production rates we find only
for the production of the scalar Higgs bosons in the non-supersymmetric
channels non-negligible cross sections of the order of $10^2$ fb.


title:
Spontaneous breaking of vector symmetries and the non-decoupling light
  Higgs particle

abstract:
  Using a four fermion interaction Lagrangian, we demonstrate that the
spontaneous breaking of vector symmetries requires the existence of a light
(comparing with the heavy fermion mass) scalar particle and the low energy
effective theory (the $\sigma$ model) obtained after integrating out heavy
fermion degrees of freedom is asymptotically a renormalizable one. When
applying the idea to the electroweak symmetry breaking sector of the standard
model, the Higgs particle's mass is of the order of the electroweak scale: $185
GeV /\sqrt{N_c} < m_H < 720 GeV /\sqrt{N_c}$ where $N_c$ is the color degrees
of freedom of the heavy fermion fields.


title: Strangeness Production in Chemically Non-Equilibrated Parton Plasma

abstract:
  Strangeness production was investigated during the equilibration of a gluon
dominated parton plasma produced at RHIC and LHC energies. The time evolution
of parton densities are followed by a set of rate equations in a 1-dimensional
expanding system. The strangeness production will depend on the initial
chemical equilibration level and in our case the parton densities will remain
far from the full equilibrium. We investigate the influence of gluon
fragmentation on final strangeness content.


title: Production Cross-sections for Unstable Particles

abstract:
  The top-quark, $W$ and $Z^0$ bosons have widths that are a sizable fraction
of their masses and will be produced copiously at upcoming accelerators. Yet
S-matrix theory cannot treat unstable particles as external states. Dealing
with complete matrix elements involving their decay products complicates
calculations considerably and is unnecessary in many practical situations. It
is shown how to construct physically meaningful production cross-sections for
unstable particles by extracting that part of the matrix element that
corresponds to finite-range space-time propagation. This procedure avoids the
need to define unstable particles in external states and we argue its favour as
providing a solution to a long-standing problem in physics. As an example the
results are applied to the calculation of the cross-section $\sigma(e^+e^-\to
Z^0Z^0)$.


title: Discovery and Identification of Extra Gauge Bosons

abstract:
  The discovery potential and diagnostic abilities of proposed future colliders
for new heavy neutral ($Z'$) and charged ($W'$) gauge bosons are summarized.
Typical bounds achievable on $M_{Z',W'}$ at the TEVATRON, DI-TEVATRON, LHC, 500
GeV NLC, and 1 TeV NLC are $\sim$1~TeV, $\sim$2~TeV, $\sim$4~TeV, 1--3~TeV, and
2--6~TeV, respectively. For $M_{Z'} \sim$1 TeV the LHC will have the capability
to determine the magnitude of normalized $Z'$ quark and lepton couplings to
around $10-20\%$, while the NLC would allow for determination of the couplings
(including their signs) with a factor of 2 larger error-bars, provided heavy
flavor tagging and longitudinal polarization of the electron beam is available.


title: The Invisible Renormalon

abstract:
  We study the structure of renormalons in the Heavy Quark Effective Theory, by
expanding the heavy quark propagator in powers of $1/m_Q$. We demonstrate that
the way in which renormalons appear depends on the regularisation scheme used
to define the effective theory. In order to investigate the relation between
ultraviolet renormalons and power divergences of matrix elements of
higher-dimensional operators in the heavy quark expansion, we perform
calculations in dimensional regularisation and in three different cut-off
regularisation schemes. In the case of the kinetic energy operator, we find
that the leading ultraviolet renormalon which corresponds to a quadratic
divergence, is absent in all but one (the lattice) regularisation scheme. The
nature of this ``invisible renormalon'' remains unclear.


title: Muonium-Antimuonium Conversion in Models with Dilepton Gauge Bosons

abstract:
  We examine the magnetic field dependence of the muonium($\mu^+ e^-$) -
antimuonium($\mu^- e^+$) conversion in the models which accommodate the
dilepton gauge bosons. The effective Hamiltonian for the conversion due to
dileptons turns out to be in the $(V-A)\times(V+A)$ form and, in consequence,
the conversion probability is rather insensitive to the strength of the
magnetic field. The reduction is less than $20\%$ for up to $B \approx 300$ G
and $33\%$ even in the large $B$ limit.


title: Calculation of Power Corrections to Hadronic Event Shapes

abstract:
  We compute power corrections to hadronic event shapes in $e^+e^-$
annihilation, assuming an infrared regular behaviour of the effective coupling
$\alpha_s$. With the integral of $\alpha_s$ over the infrared region as the
only non-perturbative parameter, also measured in heavy quark physics, we can
account for the empirical features of $1/Q$ corrections to the mean values of
various event shapes.


title:
Measuring transverse spin correlations by 4-particle correlations in
  $e^+ e^-\to 2 \ {\rm jets}$

abstract:
  The azimuthal distribution of pairs of particles in a jet is sensitive to the
transverse polarization of the quark initiating the jet, but with a sensitivity
that involves a nonperturbative analyzing power. We show in detail how to
measure the analyzing power from 4-hadron correlations in $e^+ e^- \to 2 \ {\rm
jets}$. We explain the combinations of particle flavor that are likely to give
the biggest effect.


title: On the validity of the reduced Salpeter equation

abstract:
  We adapt a general method to solve both the full and reduced Salpeter
equations and systematically explore the conditions under which these two
equations give equivalent results in meson dynamics. The effects of constituent
mass, angular momentum state, type of interaction, and the nature of
confinement are all considered in an effort to clearly delineate the range of
validity of the reduced Salpeter approximations. We find that for
$J\not{\hspace*{-1.0mm}=}0$ the solutions are strikingly similar for all
constituent masses. For zero angular momentum states the full and reduced
Salpeter equations give different results for small quark mass especially with
a large additive constant coordinate space potential. We also show that
$\frac{1}{m}$ corrections to heavy-light energy levels can be accurately
computed with the reduced equation.


title:
Neutrino Flavor Mixing Constrained by Accelerator and Reactor
  Experiments and Solar Neutrino Observation

abstract:
  We derive the constraints imposed on neutrino masses and mixing angles by
performing a combined analysis of the data from the Los Alamos and the other
terrestrial neutrino oscillation experiments with the assumption of the
flavor-mixing solutions to the solar neutrino problem. In a three-flavor mixing
scheme which ignores the possibility of sterile neutrinos, we obtain severe
constraints on the pattern of masses and flavor mixing of neutrinos. For
example, we show that in the standard Kobayashi-Maskawa type mixing matrix
$s_{13}^2 \lsim 10^{-2}$ independent of the choice of the solar neutrino
solutions. The constraint from the double $\beta$ decay is also discussed.


title: THE PHYSICS OF THE STANDARD MODEL HIGGS BOSON AT THE LHC

abstract:
  Some topics related to Standard Model Higgs boson physics at the Large Hadron
Collider are reviewed. Emphasis is put on an overview of QCD corrections to
Higgs boson decay and production processes. (Invited talk presented at the
XXXth Rencontres de Moriond, Les Arcs 1800, March 19-26, 1995; to appear in the
proceedings of the conference.)


title: Curvature Radiation by Ultrarelativistic Protons

abstract:
  We study pion curvature radiation by a proton, i.e. pion emission by a proton
moving along a curved trajectory. We suggest an approximate semiclassical
solution and the exact solution for which we assume that a proton moves in a
fictitious magnetic field with the Larmor radius equal to the curvature radius
of the real trajectory. As possible application we consider the pion radiation
by ultrahigh energy protons moving along curved magnetic field lines. Such
situation can occur in the magnetosphere of a young pulsar, in the
magnetosphere of the accretion disk around a black hole, and in the vicinity of
a superconducting cosmic string. The decay products of these pions, such as
high energy photons or neutrinos, can give the observable consequences of the
considered mechanism.


title: Rapidity Dependence of Strange Particle Ratios in Nuclear Collisions

abstract:
  It was recently found that in sulphur-induced nuclear collisions at 200 A GeV
the observed strange hadron abundances can be explained within a thermodynamic
model where baryons and mesons separately are in a state of relative chemical
equilibrium, with overall strangeness being slightly undersaturated, but
distributed among the strange hadron channels according to relative chemical
equilibrium with a vanishing strange quark chemical potential. We develop a
consistent thermodynamic formulation of the concept of relative chemical
equilibrium and show how to introduce into the partition function deviations
from absolute chemical equilibrium, e.~g.~an undersaturation of overall
strangeness or the breaking of chemical equilibrium between mesons and baryons.
We then proceed to test on the available data the hypothesis that the strange
quark chemical potential vanishes everywhere, and that the rapidity
distributions of all the observed hadrons can be explained in terms of one
common, rapidity-dependent function $\mu_{\rm q}(\eta)$ for the baryon chemical
potential only. The aim of this study is to shed light on the observed strong
rapidity dependence of the strange baryon ratios in the NA36 experiment.


title: "Intermediate Mass Higgs Study at $\gamma \gamma$ Colliders"

abstract:
  We present the efficient technique to extract the signal of the intermediate
mass Higgs boson from the backgrounds at future $\gamma \gamma$ colliders. For
a clear Higgs detection, it is important to fit the original electron
accelerator energy depending on the Higgs mass, to set the polarization of the
photon beams and to apply the efficient $b$ quark tagging method. We
demonstrate the extraction of information of Higgs parameters and the new
physics from the observable physical quantities. It is clearly shown that a
future $\gamma \gamma$ collider will have a rich potential for study on the new
physics, as well as the Higgs physics.


title: Are "Penguins" Black-and-White?

abstract:
  Contributions of low energy "eye" and "figure-eight" quark diagrams to the $K
\rightarrow \pi$ weak transitions are studied in a hadron- level
phenomenological approach. It is shown that these contributions may be
estimated by considering meson-cloud effects. If all intermediate mesons under
consideration are degenerate only the "eye" (low-energy penguin) diagram is
nonvanishing. When allowance is made for smaller mass of pseudoscalar mesons,
the contribution of "figure-eight" diagrams turns out to enhance the $\Delta I
= \frac{1}{2}$ (suppress the $\Delta I = \frac{3}{2}$) amplitudes naturally.
The overall long-distance-induced enhancement of the ratio of the $\Delta I =
\frac{1}{2}$ amplitudes over the $\Delta I = \frac{3}{2}$ amplitudes is
estimated at around 4-8.


title: CP violation in the lepton sector with Majorana neutrinos

abstract:
  We study CP violation in the lepton sector in extended models with
right-handed neutrinos, without and with left-right symmetry, and with
arbitrary mass terms. We find the conditions which must be satisfied by the
neutrino and charged lepton mass matrices for CP conservation. These
constraints, which are independent of the choice of weak basis, are proven to
be also sufficient in simple cases. This invariant formulation makes apparent
the necessary requirements for CP violation, as well as the size of CP
violating effects. As an example, we show that CP violation can be much larger
in left-right symmetric models than in models with only additional right-handed
neutrinos, {\it i.e.}, without right-handed currents.


title: Bethe--Salpeter equation in QCD

abstract:
  We extend to regular QCD the derivation of a confining $ q \bar{q}$
Bethe--Salpeter equation previously given for the simplest model of scalar QCD
in which quarks are treated as spinless particles. We start from the same
assumptions on the Wilson loop integral already adopted in the derivation of a
semirelativistic heavy quark potential. We show that, by standard
approximations, an effective meson squared mass operator can be obtained from
our BS kernel and that, from this, by ${1\over m^2}$ expansion the
corresponding Wilson loop potential can be reobtained, spin--dependent and
velocity--dependent terms included. We also show that, on the contrary,
neglecting spin--dependent terms, relativistic flux tube model is reproduced.


title: QCD Analysis of Deep Inelastic Diffractive Scattering at HERA

abstract:
  The QCD analysis of deep inelastic diffractive scattering is performed
assuming the dominance of the "soft" pomeron exchange and simple, physically
motivated parametrization of parton distributions in a pomeron. Results of the
analysis are compared with the recent data obtained by the H1 collaboration at
HERA. Both the LO and NLO approximations are considered and the theoretical
predictions concerning the quantity $R=F_L^D/F_T^D$ for diffractive structure
functions are presented.


title:
Lattice Study of Semi-Leptonic $B$ Decays: I. $\bar B\to D\ell\bar\nu$
  Decays

abstract:
  We present a study of semi-leptonic $\bar B\tp D\ell\bar\nu$ decays in
quenched lattice QCD through a calculation of the matrix element $\la D|\bar
c\gamma_\mu b|\bar B\ra$ on a $24^3\times 48$ lattice at $\beta=6.2$, using an
$\ord{a}$-improved fermion action. We perform the calculation for several
values of the initial and final heavy-quark masses around the charm mass, and
three values of the light-(anti)quark mass around the strange mass. We extract
the form factors $h^+$ and $h^-$. After radiative corrections, we find that
$h^+$ displays no dependence on the heavy-quark mass, enabling us to identify
it with an Isgur-Wise function. Thus, we obtain Isgur-Wise functions relevant
for $\bar B_s\to D_s^{(*)}\ell\bar\nu $ and $\bar B\to D^{(*)}\ell\bar\nu $
decays. We then use these functions, in conjunction with heavy-quark effective
theory, to extract $V_{cb}$ with no free parameters from the $\bar B\to
D^*\ell\bar\nu $ decay rate measured by the ALEPH, ARGUS and CLEO
collaborations. We also use our Isgur-Wise functions and heavy-quark effective
theory to calculate branching ratios for $\bar B_s\to D_s^{(*)}\ell\bar\nu $
and $\bar B\to D^{(*)}\ell\bar\nu $ decays.


title:
HERBVI - a program for simulation of baryon- and lepton- number
  violating processes

abstract:
  We describe a Monte Carlo event generator for the simulation of baryon- and
lepton-number violating processes at supercolliders. The package, {\HERBVI}, is
designed as a hard-process generator interfacing to the general hadronic event
simulation program {\HW}. In view of the very high multiplicity of gauge bosons
expected in such processes, particular attention is paid to the efficient
generation of multiparticle phase space. The program also takes account of the
expected colour structure of baryon-number violating vertices, which has
important implications for the hadronization of the final state.


title:
Representations of the $U_q(u_{4,1})$ and a $q$-polynomial that
  determines baryon mass sum rules

abstract:
  With quantum groups $U_q(su_n)$ taken as classifying symmetries for hadrons
of $n$ flavors, we calculate within irreducible representation
$D^+_{12}(p-1,p-3,p-4;p,p-2)$ ($p \in {\bf Z}$) of 'dynamical' quantum group
$U_q(u_{4,1})$ the masses of baryons ${1\over 2}^+$ that belong to ${\it
20}$-plet of $U_q(su_4)$. The obtained $q$-analog of mass relation (MR) for
$U_q(su_3)$-octet contains unexpected mass-dependent term multiplied by the
factor ${A_q\over B_q}$ where $A_q,$ $B_q$ are certain polynomials (resp. of
7-th and 6-th order) in the variable $q+q^{-1}\equiv [2]_q$. Both values $q=1$
and $q=e^{i\pi \over 6}$ turn the polynomial $A_q$ into zero. But, while $q=1$
results in well-known Gell-Mann--Okubo (GMO) baryon MR, the second root of
$A_q$ reduces the $q$-MR to some novel mass sum rule which has irrational
coefficients and which holds, for empirical masses, even with better accuracy
than GMO mass sum rule.


title: SUPERSYMMETRY REACH OF AN UPGRADED TEVATRON COLLIDER

abstract:
  We examine the capability of a $\sqrt{s}=2$ TeV Tevatron $p\bar p$ collider
to discover supersymmetry, given a luminosity upgrade to amass $25\ fb^{-1}$ of
data. We compare with the corresponding reach of the Tevatron Main Injector
($1\ fb^{-1}$ of data). Working within the framework of minimal supergravity
with gauge coupling unification and radiative electroweak symmetry breaking, we
first calculate the regions of parameter space accessible via the clean
trilepton signal from $\tw_1\tz_2\to 3\ell +\eslt$ production, with detailed
event generation of both signal and major physics backgrounds. The trilepton
signal can allow equivalent gluino masses of up to $m_{\tg}\sim 600-700$ GeV to
be probed if $m_0$ is small. If $m_0$ is large, then $m_{\tg}\sim 500$ GeV can
be probed for $\mu <0$; however, for $\mu >0$ and large values of $m_0$, the
rate for $\tz_2\to\tz_1\ell\bar{\ell}$ is suppressed by interference effects,
and there is {\it no} reach in this channel. We also examine regions where the
signal from $\tw_1\overline{\tw_1}\to \ell\bar{\ell}+\eslt$ is detectable.
Although this signal is background limited, it is observable in some regions
where the clean trilepton signal is too small. Finally, the signal
$\tw_1\tz_2\to jets+\ell\bar{\ell} +\eslt$ can confirm the clean trilepton
signal in a substantial subset of the parameter space where the trilepton
signal can be seen. We note that although the clean trilepton signal may allow
Tevatron experiments to identify signals in regions of parameter space beyond
the reach of LEP II, the dilepton channels generally probe much the same region
as LEP II.


title: Model-Independent Extraction of |V_{cb}| Using Dispersion Relations

abstract:
  We present a method for parametrizing heavy meson semileptonic form factors
using dispersion relations, and from it produce a two-parameter description of
the B -> B elastic form factor. We use heavy quark symmetry to relate this
function to B->D* l \nu form factors, and extract
|V_{cb}|=0.037^{+0.003}_{-0.002} from experimental data with a least squares
fit. Our method eliminates model-dependent uncertainties inherent in choosing a
parametrization for the extrapolation of the differential decay rate to
threshold. The method also allows a description of B -> D l nu form factors
accurate to 1% in terms of two parameters.


title:
Energy and Atomic Mass Dependence of Nuclear Stopping Power in
  Relativistic Heavy-Ion Collisions in Interacting Gluon Model

abstract:
  We present a Monte-Carlo simulation of energy deposition process in
relativistic heavy-ion collisions based on a new realization of the
Interacting-Gluon-Model (IGM) for high energy $N-N$ collisions. In particular
we show results for proton spectra from collisions of $E_{lab}=200 \ GeV/N$
$^{32}$S beam incident on $^{32}$S target and analyze the energy and mass
dependence of nuclear stopping power predicted by our model. Theoretical
predictions for proton rapidity distributions of both $^{208}$Pb + $^{208}$Pb
collisions at $E_{lab}=160 \ GeV/N$ CERN SPS and $^{197}$Au + $^{197}$Au at
$\sqrt{s_{NN}}=200 \ GeV$ BNL RHIC are given.


title:
The Mixed-Isospin Vector Current Correlator in Chiral Perturbation
  Theory and QCD Sum Rules

abstract:
  The mixed-isospin vector current correlator, $\langle 0\vert T(V^\rho_\mu
V^\omega_\nu )\vert 0\rangle$ is evaluated using both QCD sum rules and Chiral
Perturbation Theory (ChPT) to one-loop order. The sum rule treatment is a
modification of previous analyses necessitated by the observation that those
analyses produce forms of the correlator that fail to be dominated, near
$q^2=0$, by the most nearby singularities. Inclusion of contributions
associated with the $\phi$ meson rectify this problem. The resulting sum rule
fit provides evidence for a significant direct $\omega\rightarrow\pi\pi$
coupling contribution in $e^+e^-\rightarrow\pi^+\pi^-$. It is also pointed out
that results for the $q^2$-dependence of the correlator cannot be used to
provide information about the (off-shell) $q^2$-dependence of the off-diagonal
element of the vector meson propagator unless a very specific choice of
interpolating fields for the vector mesons is made. The results for the value
of the correlator near $q^2=0$ in ChPT are shown to be more than an order of
magnitude smaller than those extracted from the sum rule analysis and the
reasons why this suggests slow convergence of the chiral series for the
correlator given.


title: Rho - omega mixing in chiral perturbation theory

abstract:
  In order to calculate the rho - omega mixing we extend the chiral couplings
of the low-lying vector mesons in chiral perturbation theory to a lagrangian
that contains two vector fields. We determine the momentum dependence of the
two-point function and recover an earlier result for the on-shell expression.
We discuss the off-shell behaviour of the mixing.


title:
Radiative Electroweak symmetry breaking in the MSSM and Low Energy
  Thresholds

abstract:
  We study Radiative Electroweak Symmetry Breaking in the Minimal
Supersymmetric Standard Model (MSSM). We employ the 2-loop Renormalization
Group equations for running masses and couplings taking into account sparticle
threshold effects. The decoupling of each particle below its threshold is
realized by a step function in all one-loop Renormalization Group equations
(RGE). This program requires the calculation of all wavefunction, vertex and
mass renormalizations for all particles involved. Adapting our numerical
routines to take care of the succesive decoupling of each particle below its
threshold, we compute the mass spectrum of sparticles and Higgses consistent
with the existing experimental constraints. The effect of the threshold
corrections is in general of the same order of magnitude as the two-loop
contributions with the exception of the heavy Higgses and those neutralino and
chargino states that are nearly


title: Static Quantities of the W bosons in the MSSM

abstract:
  I discuss the static quantities of the W boson, magnetic dipole and electric
quadrupole moments, in the context of the minimal supersymmetric standard
model, in which supersymmetry is broken by soft terms $A_o,\, m_o,\, M_{1/2}$.
Following a renormalization group analysis it is found that the supersymmetric
values of $\Delta k_{\gamma}$ and $\Delta Q_{\gamma}$ can be largely different,
in some cases, from the standard model predictions but of the same order of
magnitude for values of \quad $A_0,m_0,M_{1/2} \leq {\cal O}(1 TeV) $.
Therefore possible supersymmetric structure can be probed provided the accuracy
of measurements for $\Delta k_{\gamma}$, $\Delta Q_{\gamma}$ reaches
$10^{-2}-10^{-3}$ and hence hard to be detected at LEP2. In cases where
$M_{1/2} \ll A_0,m_0 $, the charginos and neutralinos may give substantial
contributions saturating the LEP2 sensitivity limits. This occurs when their
masses $m_{\tilde C},m_{\tilde Z}$ turn out to be both light satisfying
$m_{\tilde C}+m_{\tilde Z} \simeq M_W $. However these extreme cases are
perturbatively untrustworthy and besides unnatural for they occupy a small
region in the parameter space.


title: IMPROVED METASTABILITY BOUNDS ON THE STANDARD MODEL HIGGS MASS

abstract:
  Depending on the Higgs-boson and top-quark masses, $M_H$ and $M_t$, the
effective potential of the Standard Model at finite (and zero) temperature can
have a deep and unphysical stable minimum $\langle \phi(T)\rangle$ at values of
the field much larger than $G_F^{-1/2}$. We have computed absolute lower bounds
on $M_H$, as a function of $M_t$, imposing the condition of no decay by thermal
fluctuations, or quantum tunnelling, to the stable minimum. Our effective
potential at zero temperature includes all next-to-leading logarithmic
corrections (making it extremely scale-independent), and we have used pole
masses for the Higgs-boson and top-quark. Thermal corrections to the effective
potential include plasma effects by one-loop ring resummation of Debye masses.
All calculations, including the effective potential and the bubble nucleation
rate, are performed numerically, and so the results do not rely on any kind of
analytical approximation. Easy-to-use fits are provided for the benefit of the
reader. Conclusions on the possible Higgs detection at LEP-200 are drawn.


title: Production of heavy quarks and heavy quarkonia

abstract:
  Uncertainties in the next-to-leading-order calculations of heavy-quark ($Q$)
production are investigated. Predictions for total cross sections,
single-inclusive distributions of heavy quarks and heavy flavoured hadrons, as
well as for $Q\bar{Q}$ correlations, are compared with charm and bottom data.
  The description of heavy-quarkonium production requires a separation of the
short-distance scale of $Q\bar{Q}$ production, which is set by the heavy-quark
mass from the longer-distance scales associated with the bound-state formation.
Various factorization approaches are compared, in particular with respect to
the different constraints imposed on the colour and angular-momentum states of
the $Q\bar{Q}$ pair(s) within a specific quarkonium state. Theoretical
predictions are confronted with data on heavy-quarkonium production at
fixed-target experiments and also at $p\bar{p}$ colliders, where fragmentation
gives the leading-twist cross section in $1/p_T^2$ and $1/m^2$ at high
transverse momentum.


title: SUPERSYMMETRY BREAKING IN THE NAMBU-JONA-LASINIO APPROACH

abstract:
  Gaugino condensation in the hidden sector of supergravity models is described
within a Nambu-Jona-Lasinio type of approach by minimization of a one-loop
scalar potential. The essential ingredients of the mechanism are auxiliary
superfields whose v.e.v. generate gaugino condensation and supersymmetry
breaking, introduced through Lagrange multipliers. For phenomenologically
acceptable values of the gauge couplings, gaugino condensation is disfavoured
in this approach. For completeness, it is shown that supersymmetry breaking
would occur for a stronger coupling, but at a scale inconsistent with the
expectations.


title:
Expansion, Thermalization and Entropy Production in High-Energy Nuclear
  Collisions

abstract:
  The thermalization process is studied in an expanding parton gas using the
Boltzmann equation with two types of collision terms. In the relaxation time
approximation we determine the criteria under which a time-dependent relaxation
time leads to thermalization of the partons. We calculate the entropy
production due to collisions for the general time-dependent relaxation time. In
a perturbative QCD approach on the other hand, we can estimate the parton
collision time and its dependence on expansion time. The effective `out of
equilibrium' collision time differs from the standard transport relaxation
time, $\tau_{\rm tr}\simeq(\alpha_s^2\ln(1/\alpha_s)T)^{-1}$, by a weak time
dependence. It is in both cases Debye screening and Landau damping that
regulate the singular forward scattering processes. We find that the parton gas
does thermalize eventually but only after having undergone a phase of free
streaming and gradual equilibration where considerable entropy is produced
(``after-burning"). The final entropy and thus particle density depends on the
collision time as well as the initial conditions (a ``memory effect"). Results
for entropy production are presented based upon various model estimates of
early parton production.


title: Scaling and Diffraction in Deep Inelastic Scattering

abstract:
  We pursue the hypothesis that the events with a large rapidity gap, observed
at HERA, reflect the scattering of electrons off lumps of wee partons inside
the proton. A simple scaling behaviour is predicted for the diffractive
structure functions, which are related to the inclusive structure function
$F_2(x,Q^2)$ at small values of the scaling variable $x$. The results are
compared with recent measurements of the diffractive structure function
$F_2^D(x,Q^2,M^2)$.


title: Future $\nu_\tau$ Oscillation Experiments and Present Data

abstract:
  Our goal in this paper is to examine the discovery potential of laboratory
experiments searching for the oscillation $\nu_\mu(\nu_e) \rightarrow
\nu_\tau$, in the light of recent data on solar and atmospheric neutrino
experiments, which we analyse together with the most restrictive results from
laboratory experiments on neutrino oscillations. In order to explain
simultaneously $all$ present results we use a four-neutrino framework, with an
additional sterile neutrino. Our predictions are rather pessimistic for the
upcoming experiments NOMAD and CHORUS, which, we find, are able to explore only
a small area of the oscillation parameter space. On the other hand, the
discovery potential of future experiments is much larger. We consider three
examples. E803, which is approved to operate in the future Fermilab main
injector beam line, MINOS, a proposed long-baseline experiment also using the
Fermilab beam, and NAUSICAA, an improved detector which improves by an order of
magnitude the performance of CHORUS/NOMAD and can be operated either at CERN or
at Fermilab beams. We find that those experiments can cover a very substantial
fraction of the oscillation parameter space, having thus a very good chance of
discovering $both$ $\nu_\mu \rightarrow \nu_\tau$ and $\nu_e \rightarrow
\nu_\tau$ oscillation modes.


title:
BFKL predictions at small x from k_T and collinear factorization
  viewpoints

abstract:
  Hard scattering processes involving hadrons at small $x$ are described by a
$k_T$-factorization formula driven by a BFKL gluon. We explore the equivalence
of this description to a collinear-factorization approach in which the
anomalous dimensions $\gamma_{gg}$ and $\gamma_{qg}/\alpha_S$ are expressed as
power series in $\alpha_S \log (1/x)$, or to be precise $\alpha_S/\omega$ where
$\omega$ is the moment index. In particular we confront the
collinear-factorization expansion with that extracted from the BFKL approach
with running coupling included.


title: On the Universality of the Leading, $1/Q$ Power Corrections in QCD

abstract:
  We discuss $1/Q$ corrections to hard processes in QCD where $Q$ is a large
mass parameter like the total energy in $e^+e^-$ annihilation. The main problem
we address ourselves to is whether these corrections to different processes
(concentrating for definiteness on the Thrust and the Drell-Yan cross section)
can be related to each other in a reliable way so that the phenomenology of the
$1/Q$ corrections can be developed. We derive first the relation valid to
lowest order using both the renormalon and finite-gauge-boson mass techniques
to check its independence on the infrared cut- off procedure. We then argue
that the $1/Q$ corrections are due to soft gluons which factorize into a
universal factor such that the lowest order relations are preserved in higher
orders.


title: LATTICE QCD AND THE STANDARD MODEL

abstract:
  Most of the poorly known parameters of the Standard Model cannot be
determined without reliable calculations in nonperturbative QCD. Lattice gauge
theory provides a first-principles definition of the required functional
integrals, and hence offers ways of performing these calculations. This paper
reviews the progress in computing hadron spectra and electroweak matrix
elements needed to determine $\alpha_S$, the quark masses, and the
Cabibbo-Kobayashi-Maskawa matrix.


title: Chiral Restoration in Hot and/or Dense Matter

abstract:
  Chiral restoration phase transition in hot and/or dense hadronic matter is
discussed in terms of the BR scaling based on chiral symmetry and scale anomaly
of QCD. The precise connection between the scalar field that figures in the
trace anomaly and the sigma field that figures in the linear $\sigma$ model is
established. It is suggested that in hot and/or dense medium, the nonlinear
$\sigma$ model linearizes with the help of a dilaton to a linear $\sigma$ model
with medium-renormalized constants. The relevance of Georgi's vector symmetry
and/or Weinberg's ``mended symmetry" in chiral restoration is pointed out. Some
striking consequences for relativistic heavy-ion collisions and dense matter in
compact stars following stellar collapse are discussed.


title: TWO--SPIN ASYMMETRY OF HEAVY QUARKONIA PRODUCTIONS AT RHIC ENERGY

abstract:
  Hadroproductions of charmonium and bottomonium $\chi_J$ in polarized $pp$
collisions at RHIC energies are studied. Two--spin asymmetries
$A_{LL}^{\chi_J}(pp)$ for these reactions are very good parameters for
examining the polarized gluon distributions in a proton.


title:
Comparison of Chiral Perturbation Theory and QCD Sum Rule Results for
  Pseudoscalar Isoscalar-Isovector Mixing

abstract:
  The forms of the neutral, non-strange pseudoscalar propagator matrix and
mixed axial current correlator, $\lngle0|T(A_\mu^3 A_\nu^8)|0\rangle$, are
discussed at next-to-leading (one-loop) order in chiral perturbation theory,
and the results compared to those obtained using QCD sum rules. This comparison
provides a check of the truncations employed in the sum rule treatment of the
current correlator. Values for the slope of the correlator with $q^2$ in the
two approaches are found to differ by more than an order of magnitude and the
source of this discrepancy is shown to be the incorrect chiral behavior of the
sum rule result.


title:
Strong Isospin Mixing Effects on the Extraction of $\Delta I=3/2$
  Non-Leptonic Hyperon Decay Amplitudes

abstract:
  The existence of isospin admixtures in the physical $\Lambda$, $\pi^o$
complicates the extraction of Delta I=3/2 non-leptonic hyperon decay amplitudes
from experimental data, allowing contributions associated with large Delta
I=1/2 amplitudes to appear in the (nominally) Delta I=3/2 amplitudes obtained
ignoring these admixtures. We show how to correct for this effect to leading
order in $(m_d-m_u)$ and extract the true Delta I=3/2 amplitudes. The resulting
corrections are modest ($<25\%$) for s-waves, but extremely large, $\simeq
100\%$ and $\simeq 400\%$ for $\Lambda$ and $\Xi$ p-waves, respectively.


title: On the Dirac quantization condition

abstract:
  We revisit the Dirac quantization condition for string-like and string-less
(but multi-valued) magnetic monopole potentials. In doing so we allow for an
{\it a priori} different coupling ${\tilde e}$ associated with the longitudinal
components of the gauge potential. By imposing physical criteria in the choice
of the longitudinal--transverse decomposition we show that -in contrast to some
recent claims- the `unphysical' coupling $\tilde e$ does not appear in the
quantization condition.


title: Inelastic $J/\psi$ photoproduction

abstract:
  Inelastic photoproduction of $J/\psi$ particles at high energies is one of
the processes to determine the gluon distribution in the nucleon. The QCD
radiative corrections to the color-singlet model of this reaction have recently
been calculated. They are large at moderate photon energies, but decrease with
increasing energies. I compare the cross section and the ${J/\psi}$ energy
spectrum with the available fixed-target photoproduction data. Predictions for
the HERA energy range are given which demonstrate the sensitivity of the result
to the parametrization of the gluon distribution in the small-$x$ region. (Talk
presented at the Workshop on "Heavy Quark Physics", Bad Honnef, FRG, Dec. 1994)


title:
A Self-consistent Inclusion of Magnetic Screening for the Quark-Gluon
  Plasma

abstract:
  We discuss how magnetic screening can be systematically included in a
self-consistent way for Chromodynamics at high temperatures. The resulting gap
equation, which gives the summation of self-energy iterations, is calculated to
one-loop order and leads to a nonzero value for the magnetic mass.


title: Charged Leptons With Nanosecond Lifetimes

abstract:
  Some extensions of the standard model contain additional leptons which are
vectorlike under weak isospin. A class of models is considered in which these
leptons do not appreciably mix with the known leptons. In such models, the
heavy charged lepton and the heavy neutrino are degenerate in mass, and the
degeneracy is broken by radiative corrections. The mass splitting is calculated
and found to be very weakly dependent on the lepton mass, varying from 250 to
330 MeV as the mass varies from 100 to 800 GeV. This result is {\it not}
affected significantly by inclusion in a supersymmetric model in spite of the
additional loops involving the superpartners. As a result, this fairly general
class of models has a charged lepton whose lifetime varies in the narrow range
from 0.5 to 2.0 nanoseconds, and which decays into neutrals plus a very low
energy electron or muon.


title: Effective Theory Approach to SUSY Hadron Spectroscopy

abstract:
  Supersymmetric hadrons of the type $\tg\tg$, $\tg g$ and $\tg q\bar q$ could
exist depending on the masses of the gluino and the squarks being in an
appropriate range of values. We find the energy levels of $\tg g$ and $\tg
q\bar q$ bound states (where $q$ denotes a light quark, $u$, $d$ or $s$), as
well as the strong interaction transition rates among them, using a Heavy
Gluino Effective Theory, much in the same spirit as the well-known Heavy Quark
Effective Theory. The results are obtained with greater ease and elegance in
comparison to other approaches.


title: Three Generations or More for an Attractive Gravity?

abstract:
  We calculate the induced Einstein action from supersymmetric models in
general space-time. Supersymmetric models consist of two kinds of
supermultiplets, called scalar supermultiplets and vector supermultiplets,
respectively. We show that the vector multiplets generate a negative Newton
constant, while the scalar multiplets a positive one. Then we find that the
positivity of Newton constant depends on the ratio of the number of scalar
multiplets to one of vector multiplets. If we apply this result to two hopeful
supersymmetric unified models: one is minimal SUSY standard model and another
is minimal SUSY SU(5) GUT, we are led to the conclusion that we need more than
or equal to three generations of quark and lepton multiplets to have a positive
Newton constant, i.e., an attractive gravity.


title:
Explicit $CP$ Violation of the Higgs Sector in the Next-to-Minimal
  Supersymmetric Standard Model

abstract:
  We study the explicit $CP$ violation of the Higgs sector in the minimal
supersymmetric standard model with a gauge singlet Higgs field. The magnitude
of $CP$ violation is discussed in the limiting cases of $x\gg v_1,\ v_2$ and
$x\ll v_1,\ v_2$, where $x$ and $v_{1,2}$ denote VEV of singlet and doublet
Higgs scalars, respectively. Our numerical predictions of the electric dipole
moments of electron and neutron lie around the present experimental upper
limits. It is found that the large $CP$ violation effect reduces the magnitude
of the lightest Higgs boson mass in the order of a few ten GeV.


title:
Another look at the angular distributions of the $\gamma\gamma\to\pi
  \pi$ reactions

abstract:
  We analyze the existing data on the angular distributions of the
$\gamma\gamma\to \pi^+ \pi^- ,\pi^0 \pi^0$ reactions with using of the unitary
model for helicity 2 amplitude. The purpose is to obtain the D--wave parameters
and S--wave cross section. We obtain from experiment in the first time the
values of $\alpha + \beta$ for sum of the electric and magnetic pion's
polarizabilities. We found the S-wave cross sections much smaller as compared
with previous similar analysis. Comparison of the $\gamma\gamma\to \pi^+ \pi^-$
and $\gamma\gamma\to \pi^0 \pi^0$ data gives an indication for a marked I = 2,
J = 2 contribution in region of $f_2(1270)$.


title:
Factorization versus Duality in Nonleptonic decays, a Quark Model
  Approach

abstract:
  We study in a quark model the contradiction between factorization and duality
found in nonleptonic decays at next to leading order in $1/N_c$, concentrating
on quark exchange mechanism. The contradiction originates in the fact that the
standard factorization assumption approximates the asymptotic final states by a
non-orthogonal set of states, thus leading to an overcounting of the decay
probability. We consider a system with two heavy quarks treated as classical
color sources with constant velocity, and two mass-degenerate antiquarks.
Exploiting permutation symmetry in an adiabatic approximation, we find that
final state interaction restores duality. Three $O(1/N_c)$ effects are
exhibited: i) a proper treatment of orthogonality yields a global correction
$1/N_c\to 1/2N_c$ within a generalized factorization \`a la BSW, (such a factor
was present in an Ansatz by Shifman), ii) the distorsion of the meson wave
functions at the time of the weak decay, iii) relative phases generated by the
later evolution. The latter effect becomes dominant for light antiquarks or for
a small velocity of the final mesons, and may thoroughly modify the
factorization picture. For exclusive decay it may interchange the role of class
I and class II final channels, and for semi-inclusive decay it may lead to an
equal sharing of the probability between the two sets of final states. In the
heavy antiquark and large velocity limit, the replacement $1/N_c\to 1/2N_c$ is
the dominant correction.