title: Constraints on the Left-Right Symmetric Model from $b\to s\gamma$

abstract:
  The recent observation by the CLEO Collaboration of the inclusive decay $b\to
s\gamma$ with a branching fraction consistent with the expectations of the
Standard Model is used to constrain the parameter space of the Left-Right
Symmetric Model. Two scenarios are considered: ($i$) equal left- and right-
handed Cabibbo-Kobayashi-Maskawa mixing matrices, $V_L=V_R (~{\rm or}~V_R^*)$
and ($ii$) the Gronau-Wakaizumi model wherein B-decays proceed only via
right-handed currents and $V_L$ and $V_R$ are quite distinct. In the later case
the bounds from $b\to s\gamma$ are combined with other constraints leaving a
parameter range that is very highly restricted and which implies that this
model may soon be completely ruled out by improving data. (To appear in the
{\it Proceedings of the 1994 International Workshop on B Physics, Physics
Beyond the Standard Model at the B Factory}, Nagoya, Japan, October 26-28,
1994.)


title: Chiral Symmetry Breaking From Dyson-Schwinger Equations

abstract:
  I report on recent progress in the study of mass generation in non-abelian
gauge theories, and concentrate on the origin of constituent masses in QCD. I
argue that a consistent formalism has been developed to describe chiral
symmetry breaking via multiplicatively renormalisable Dyson-Schwinger
equations. Its main consequence is the existence of a critical value of the
coupling beyond which massless solutions do not exist.


title: Centauro- and anti-Centauro-type events

abstract:
  Assuming that leading particles in high-energy hadronic and nuclear
collisions become sources of a classical pion field, we show that the direct
production of pions favors Centauro (mainly charged) events and that the
production of pions through the $ \rho$-type channel favors anti-Centauro
(mainly neutral) events. We also observe a strong negative neutral-charged
correlation in both cases.


title:
Can pions created in high-energy heavy-ion collisions produce a
  Centauro-type effect?

abstract:
  We study a Centauro-type phenomenon in high-energy heavy-ion collisions by
assuming that pions are produced semiclassically both directly and in pairs
through the isovector channel. The leading-particle effect and the
factorization property of the scattering amplitude in the impact-parameter
space are used to define the classical pion field. By analyzing the joint
probability function $P_{II_{3}}(n_{0},n_{\_})$ for producing $n_{0}$ neutral
and $n_{-}$ negative pions from a definite isospin state $II_{3}$ of the
incoming leading-particle system we show that only direct production of pions
without isovector pairs favors Centauro-type behavior. The presence of
isovector pairs seems to destroy the effect. Our conclusion is supported
through the calculation of two pion correlation parameters, $f_{2}^{0-}$ and
$f_{2}^{00}$, and the average number of neutral pions $(< n_{0} >_{n_{\_}})$ as
a function of negative pions $(n_{\_})$ produced.


title: Vector Dominance Effects in Weak Radiative Decays of the B Mesons

abstract:
  The long distance vector-meson-dominance (VMD) effects on the weak radiative
decays $\bb\to\rho\gamma$ and $\bb^0\to D^{*0}\gamma$ are studied. For
$\bb\to\rho\gamma$ decays, the VMD contribution is $(10-20)\%$ of the
short-distance penguin amplitude. The pole effect is as important as the VMD
one in the decay $B^-\to\rho^-\gamma$, but it is suppressed in $\bb^0\to
\rho^0\gamma$. The branching ratio of $\bb\to\rho\gamma$, estimated to be of
order $10^{-6}$, strongly depends on the sign of the Wolfenstein parameter
$\rho$. A measurement of any deviation of the ratio $R=\Gamma(B^-\to\rho^-
\gamma)/\Gamma(\bb^0\to\rho^0\gamma)$ away from the isospin value 2 will not
only provide a probe on the long-range contribution but also fix the sign of
$\rho$: $R>2$ for $\rho<0$ and $R<2$ for $\rho>0$. The decay $\bb^0\to
D^{*0}\gamma$ does not receive short-distance contributions, and its branching
ratio, predicted to be $0.9\times 10^{-6}$, is dominated by $W$-exchange
accompanied by a photon emission.


title:
Phenomenological Analysis of a Dimension-Two Operator in QCD and its
  Impact on $\alpha_{s}(M_{\tau})$

abstract:
  Fits to the ARGUS data on hadronic decays of the tau-lepton, which determine
the vector and axial-vector spectral functions, are used in order to determine
the size of a dimension $d=2$ term in the Operator Product Expansion.
Constraints from the first Weinberg sum rule (in the chiral limit) are enforced
in order to reduce the uncertainty of this determination. Results for the $d=2$
operator are consistent with a quadratic dependence on $\Lambda_{QCD}$. The
impact of this term on the extraction of $\alpha_{s}(M_{\tau})$ is assessed.


title:
Semi-analytical and Monte Carlo results for the production of four
  fermions in $e^+ e^-$ collisions

abstract:
  In view of the forthcoming experiments at high energy $e^+ e^-$ colliders,
LEP2 and beyond, the process $e^+ e^- \to W^+ W^- \to 4f$ has been investigated
for {\it off-shell} $W$'s. After deriving the matrix element for the process
within the helicity amplitude formalism, QED radiative corrections to the
initial state leptons have been included at the leading logarithmic level in
the framework of the electron structure functions. Cross sections and
distributions are computed by means of both a semi-analytical and a Monte Carlo
code, allowing for several cuts of experimental interest. A Monte Carlo event
generator has also been built, for simulation purposes. Some illustrative
numerical results are included and shortly described.


title: Signatures of Higgs-Triplet Representations at Tev--e+e- Colliders

abstract:
  We investigate the potential of future TeV linear e^+e^- colliders to observe
singly-charged Higgs bosons ($H^\pm$) via the coupling $H^\pm W^\mp Z$, which
would signal the existence of exotic Higgs representations. In the context of a
Higgs-triplet model compatible with the electroweak oblique parameters, we
estimate the cross section for pro- ducing charged Higgs-triplet bosons that
couple predominantly to $W$ and $Z$ bosons in 0.5--2 TeV-$e^+e^-$ colliders.
The principal backgrounds are evaluated and the viability of the signal is
discussed and illustrated.


title:
Phase Structure and Phase Transition of the SU(2) Higgs Model in Three
  Dimensions

abstract:
  We derive a set of gauge independent gap equations for Higgs boson and vector
boson masses for the SU(2) Higgs model in three dimensions. The solutions can
be associated with the Higgs phase and the symmetric phase, respectively. In
the Higgs phase the calculated masses are in agreement with results from
perturbation theory. In the symmetric phase a non-perturbative vector boson
mass is generated by the non-abelian gauge interactions, whose value is rather
independent of the scalar self-coupling $\lambda$. For small values of
$\lambda$ the phase transition is first-order. Its strength decreases with
increasing $\lambda$, and at a critical value $\lambda_c$ the first-order
transition changes to a crossover. Based on a perturbative matching the
three-dimensional theory is related to the four-dimensional theory at high
temperatures. The critical Higgs mass $m_H^c$, corresponding to the critical
coupling $\lambda_c$, is estimated to be below 100 GeV. The ``symmetric phase''
of the theory can be interpreted as a Higgs phase whose parameters are
determined non-perturbatively. The obtained Higgs boson and vector boson masses
are compared with recent results from lattice Monte Carlo simulations.


title: CP violation in the time evolution of the decay K0 -> Pi0 e+ e-

abstract:
  We examine the possibility of extracting CP-violating terms in the decay K0
-> Pi0 e+ e- by studying the time evolution of a K0 beam. We focus on the
interference region and search for clear effects. We find that experiments
which average over the electron and positron momenta can detect CP violation as
an oscillation in the decay rate. The branching ratio is ( 3 - 5 ) * 10^(-12)
and direct CP violation dominates over a wide range of the parameters.


title: Thermal photon production in heavy ion collisions

abstract:
  Using a three-dimensional hydrodynamic simulation of the collision and an
equation of state containing a first order phase transition to the quark-gluon
plasma, we study thermal photon production for $Au+Au$ collisions at
$E_{lab}=11.5$ AGeV and for $Pb+Pb$ collisions at $160$ AGeV. We obtain
surprisingly high rates of thermal photons even at the lower energy, suggesting
that, contrary to what was expected so far, photon production may be an
interesting topic for experimental search also at the Alternating Gradient
Synchrotron. When applied to the reaction $S+Au$ at $200$ AGeV, our model can
reproduce preliminary data obtained by the WA80 Collaboration without having to
postulate the existence of an extremely long-lived mixed phase as was recently
proposed.


title:
Parity Violation in Top Quark Pair Production at the Fermilab Tevatron
  Collider

abstract:
  The leading weak corrections to the production of top quark pairs via
$q\bar{q} \to t\bar{t}$ in $p\bar{p}$ collisions are evaluated. The
chromo-anapole form factor of the top quark and effects of parity violation are
studied in the Standard Model (SM) and the Minimal Supersymmetric Model (MSSM).
The parity violation effect in $q\bar{q} \to g \to t\bar{t}$ from the SM weak
corrections is found to be very small. In the MSSM, the effects of parity
violation can be enhanced for $\tan\beta \equiv v_2/v_1 > \sqrt{m_t/m_b}$.


title:
The Evolution of the Pion Distribution Amplitude in Next-to-Leading
  Order

abstract:
  The evolution of the pion distribution amplitude in next-to-leading order is
studied for a fixed and a running coupling constant. In both cases, the
evolution provides a logarithmic modification in the endpoint region. Assuming
a simple parameterization of the distribution amplitude at a scale of $Q_0\sim
0.5\ \rm GeV$, it is shown numerically that these effects are large enough at
$Q\sim 2\ \rm GeV$ that they have to be taken into account in the
next-to-leading-order analysis for exclusive processes. Alternatively, by
introducing a new distribution amplitude that evolves more smoothly, this
logarithmic modification can be included in the hard-scattering part of the
considered process.


title: Solar Neutrinos

abstract:
  The status of the solar neutrino problem is reviewed. Attempts to explain the
observed deficit and spectral distortion, both by astrophysical and particle
physics methods, are described. It is argued that the comparison of all
experiments strongly prefers the particle physics solutions.


title: Wolfenstein Parametrization Re-examined

abstract:
  The Wolfenstein parametrization of the $3\times 3$ Kobayashi-Maskawa (KM)
matrix $V$ is modified by keeping its unitarity up to the accuracy of
$O(\lambda^{6})$. This modification can self-consistently lead to the
off-diagonal asymmetry of $V$: $|V_{ij}|^{2}-|V_{ji}|^{2}$ =
$Z\displaystyle\sum_{k}\epsilon^{~}_{ijk}$ with $Z=\approx A^{2}\lambda^{6}
(1-2\rho)$, which is comparable in magnitude with the Jarlskog parameter of
$CP$ violation $J\approx A^{2}\lambda^{6}\eta$. We constrain the ranges of $J$
and $Z$ by using the current experimental data, and point out that the
possibility of a symmetric KM matrix has almost been ruled out.


title: The neutrino cross section and upward going muons

abstract:
  The charged current cross section for neutrinos with energy of a few GeV is
reanalysed. In this energy range the cross section for the lowest multiplicity
exclusive channels is an important fraction of $\sigma_{CC}$ and the
approximation of describing the cross section with deep inelastic scattering
formulae may be inaccurate. Possible consequences of our reanalysis of the
cross section in the interpretation of the data obtained by deep underground
detectors on $\nu$--induced upward going muons (both stopping and passing) are
discussed.


title: Cosmic strings

abstract:
  The topic of cosmic strings provides a bridge between the physics of the very
small and the very large. They are predicted by some unified theories of
particle interactions. If they exist, they may help to explain some of the
largest-scale structures seen in the Universe today. They are `topological
defects' that may have been formed at phase transitions in the very early
history of the Universe, analogous to those found in some condensed-matter
systems --- vortex lines in liquid helium, flux tubes in type-II
superconductors, or disclination lines in liquid crystals. In this review, we
describe what they are, why they have been hypothesized and what their
cosmological implications would be. The relevant background from the standard
models of particle physics and cosmology is described in section 1. In section
2, we review the idea of symmetry breaking in field theories, and show how the
defects formed are constrained by the topology of the manifold of degenerate
vacuum states. We also discuss the different types of cosmic strings that can
appear in different field theories. Section 3 is devoted to the dynamics of
cosmic strings, and section 4 to their interaction with other fields. The
formation and evolution of cosmic strings in the early Universe is the subject
of section 5, while section 6 deals with their observational implications.
Finally, the present status of the theory is reviewed in section 7.


title: Anomalous Cross Section from Perturbation Theory

abstract:
  We present the anomalous cross section for baryon number violation in the
standard model from the perturbation of large-order behavior of forward
scattering amplitudes to the order $\left(\epsilon /n\right)^{8/3}
\ln\left(\epsilon /n\right)$. An improved high energy behavior of the anomalous
cross section is observed. We also argue that the asymptotic form of
$F(\epsilon g) \equiv -g \ln \sigma_{ano} $ is given in the form: $F(\epsilon
g) \rightarrow d + c \cdot \epsilon g $ for $ \epsilon g \rightarrow \infty$
with $c, d $ constants satisfying $c, d \geq 0$, and $F(\epsilon g) >0$ for all
energies. The constants are not determined.


title:
The simplest form of the $\kappa$ and $\kappa^2$ order graviton
  self-interaction Lagrangian density in the weak field approximation

abstract:
  We derive the simplest form of the $\kappa(\kappa^2)$ order graviton
self-interaction Lagrangian density $\lag{1}(\lag{2})$ in the weak field
approximation. With the divergenceless condition, de Donder gauge and some
combinatoric techniques, we derive the mathematically independent basis
expressions for $\lag{1}(\lag{2})$ composed of 8(24) terms. By using the basis
expressions $\lag{1}(\lag{2})$ is reduced to 6(18) terms.


title: Nonperturbative QCD Effects in High Energy Collisions

abstract:
  High energy hadron-hadron collisions are discussed. It is argued that soft
collisions should involve in an essential way nonperturbative QCD. A way is
outlined how to calculate properties of high energy elastic hadron-hadron
scattering using field theoretic methods. The functional integrals occuring
there are evaluated using the ``stochastic vacuum model''. A satisfactory
comparison between theory and experiment is achieved. Then the question of
possible nonperturbative QCD effects in high energy hard hadron-hadron
collisions is raised. It is shown that some spin effects in the Drell-Yan
process may give a hint that such effects exist indeed in nature.


title:
Hadronic Matter with Internal Symmetries and its Consequences: An
  Expanding Hadronic Gas

abstract:
  We consider an ideal gas of massive hadrons in thermal and chemical
equilibrium. The gas expands longitudinally in accordance with Bjorken law.
Strangeness and baryon number conservation is taken into account. This gas has
different features as compared to the pion gas.


title: Light Neutralinos in B-Decays

abstract:
  We consider the decays of a $B_s$-meson into a pair of lightest
supersymmetric particles (LSP) in the minimal supersymmetric standard model. It
is found that the parameter space for light LSP's in the range of 1 GeV can be
appreciably constrained by looking for such decays.


title: Electroweak Strings, Zero Modes and Baryon Number

abstract:
  The Dirac equations for leptons and quarks in the background of an
electroweak $Z-$string have zero mode solutions. If two loops of electroweak
string are linked, the zero modes on one of the loops interacts with the other
loop via an Aharanov-Bohm interaction. The effects of this interaction are
briefly discussed and it is shown that the fermions induce a baryon number on
linked loops of $Z-$string. (Submitted to Proceedings of "Trends in
Astrophysics" Conference, Stockholm, 1994.)


title: On the charge dependence of factorial moments in $e^+e^-$ processes

abstract:
  The behaviour of like-charge and unlike-charge second factorial moments in
$e^+e^-$ reactions is discussed. It is argued that Monte Carlo calculation with
the help of generators JETSET 7.4 and HERWIG 5.8 points to the conclusion that
the only nontrivial cause of intermittency are Bose-Einstein correlations of
identical particles.


title: Searching For SUSY Dark Matter

abstract:
  {\tenrm The possibility of detecting supersymmetric dark matter is examined
within the framework of the minimal supergravity model (MSGM), where the
$\tilde{Z}_{1}$ is the LSP for almost the entire parameter space. A brief
discussion is given of experimental strategies for detecting dark matter. The
relic density is constrained to obey 0.10 $\leq \Omega_{\tilde{Z}_{1}}h^2
\leq$0.35, consistent with COBE data. Expected event rates for an array of
possible terrestial detectors ($^3$He, CaF$_2$, Ge, GaAs, NaI and Pb) are
examined. In general, detectors relying on coherrent $\tilde{Z}_{1}$-nucleus
scattering are more sensitive than detectors relying on incoherrent
(spin-dependent) scattering. The dependence of the event rates as a function of
the SUSY parameters are described. The detectors are generally most sensitive
to the small $m_0$ and small $m_{\tilde{q}}$ and large tan$\beta$ part of the
parameter space. The current $b\rightarrow s+\gamma$ decay rate eliminates
regions of large event rates for $\mu >0$, but allows large event rates to
still occur for $\mu<0$. MSGM models that also possess SU(5)-type proton decay
generally predict event rates below the expected sensitivity of current dark
matter detectors.}


title:
Critical Scattering at the Chiral Phase Transition and low-p_t
  enhancement of mesons in ultra-relativistic heavy-ion collisions

abstract:
  The enhancement of pions and kaons observed at small transverse momenta in
ultra-relativistic heavy-ion collisions may at least partly reflect critical
scattering expected to occur in the neighborhood of a second order phase
transition. Kinetic equations in the relaxation time approximation are proposed
for the time evolution of the quark distribution function into that of the
pions. Relaxation times for thermalization and hadronization processes are
functions of momenta and approach zero in the limit p->0, a consequence of
criticality at the phase transition. Data can be reproduced for suitably chosen
parameters.


title: Geometry of Multihadron Production

abstract:
  Summary talk given at the 24th International Symposium on Multiparticle
Dynamics, Italy, September 1994 -- This summary talk only reviews a small
sample of topics featured at this symposium: 1. Introduction 2. The Geometry
and Geography of Phase space 3. Space-Time Geometry and HBT 4. Multiplicities,
Intermittency, Correlations 5. Disoriented Chiral Condensate 6. Deep Inelastic
Scattering at HERA 7. Other Contributions


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

abstract:
  We reevaluate the hadronic part of the electromagnetic vacuum expectation
value using the standard dispersion integral approach that utilizes the
hadronic cross section measured in $\ee$ experiments as input. Previous
analyses are based upon point-by-point trapezoidal integration which has the
effect of weighting all inputs equally. We use a technique that weights the
experimental inputs by their stated uncertainties, includes correlations, and
incorporates some refinements. We find the hadronic contribution to the
fractional change in the electromagnetic coupling constant at $q^2=M_Z^2$ to be
$0.02666\pm0.00075$, which leads to a value of the electromagnetic coupling
constant, $\alpha^{-1}(M_Z^2) = 129.08\pm0.10$. This value significantly shifts
the Standard Model predictions for the effective weak mixing angle measured at
the $Z$ pole and moderately shifts the predicted $Z$ width.


title: A Property of Recombination in Polarized Hadronic Targets

abstract:
  The triple gluon-ladder vertex is shown to project the outgoing gluon in
either polarization state with equal probability up to the leading
double-ln(x)ln($Q^2$) approximation. This implies that the $Q^2$-evolution of
$\Delta G (x, Q^2)$ is free from recombination effects to this level of
approximation.


title: Is there a Vector Boson Coupling to Baryon Number?

abstract:
  Discrepancies in measurements of the QCD running coupling constant are
consistent with a new vector gauge boson coupling to baryon number with
strength aB~0.1. Upsilon decays constrain such a boson to have a mass greater
than about 35 GeV. It is difficult to observe such a boson in Z decays, e+e-
annihilation, or hadronic interactions.


title: The Lamb Shift of Hydrogen and Low-Energy Tests of QED

abstract:
  Leading logarithmic corrections to the difference of Lamb shifts of s-states
$E_L(1s)-8E_L(2s)$ and to the life time of $2p_{1/2}$ state are considered. The
result of Sokolov and Yakovlev for the Lamb splitting of $2s_{1/2}$ and
$2p_{1/2}$ is re-evaluated and our new value is 1057.8576(21) MHz. Using value
of $E_L(1s)-8E_L(2s)=$ -187.237(8) MHz, obtained here, a new value of the
Hydrogen and Deuterium ground states using all recent measurements connected
with 1s or 2s Lamb shifts. The highest precision value for the Hydrogen ground
state is obtained from corrected result of Sokolov and Yakovlev experiment as
8172.934(22) MHz.
  The Deuterium result is $E_L(1s)-8E_L(2s)=$ -187.229(8) MHz, using it we
obtain from the Garching experiment 8183.905(224) MHz.
  Some related topics are also considered. Taking into account nearest future
result the fine structure constant problem are reviewed. Special attention is
payed to Muonium hyperfine splitting, which it is done simillar to Lamb shift
calculatuion for and to the neutron de Broglie's wave length measurements which
also could lead to some connection between the Deuterium mass and the fine
structure constant.


title: Predictions of the Top mass in Mininal Supersymmetric Left-Right Model

abstract:
  The one-loop evolution of Yukawa couplings in the minimal supersymmetric
left-right model (MSUSYLR) model with a wide variation of the right handed
breaking scale $M_R$ from 1 TeV to $10^{18}$ GeV is studied assuming that all
third generation Yukawa couplings are equal and in the fixed point domain of
the top quark Yuakwa coupling ($h_t$) at the Plank scale. We show that: (1) The
top quark Yukawa coupling $h_t$ displays a fixed point behaviour that is
similar to that of the minimal supersymmetric standard model (MSSM). (2) The
MSUSYLR model predicts a value of the top mass in the interval 177 to 184 GeV
for $\alpha_s$ in the interval 0.11 to 0.12. (3) A large value of $tan\beta$ is
required to reproduce the correct mass of the bottom quark and tau lepton. (4)
With the experimental value of the ratio ${m_b(m_b) \over m_\tau(m_\tau)}$ as
an input the range of the right handed symmetry breaking scale $M_R$ can be
predicted. (5) The numerical value of the Majorana Yukawa coupling $h_M$ can be
calculated which is otherwise a completely free parameter.


title:
Pion and thermal photon spectra as a possible signal for a phase
  transition

abstract:
  We calculate thermal photon and neutral pion spectra in ultrarelativistic
heavy-ion collisions in the framework of three-fluid hydrodynamics. Both
spectra are quite sensitive to the equation of state used. In particular,
within our model, recent data for $S+Au$ at $200$ AGeV can only be understood
if a scenario with a phase transition (possibly to a quark-gluon plasma) is
assumed. Results for $Au+Au$ at $11$ AGeV and $Pb+Pb$ at $160$ AGeV are also
presented.


title: Aspects of four-jet production in polarized proton-proton collisions

abstract:
  We examine the intrinsic spin-dependence of the dominant $gg \rightarrow
gggg$ subprocess contribution to four-jet production in polarized proton-proton
collisions using helicity amplitude techniques. We find that the partonic
level, longitudinal spin-spin asymmetry, $\hat{a}_{LL}$, is intrinsically large
in the kinematic regions probed in experiments detecting four isolated jets.
Such events may provide another qualitative or semi-quantitative test of the
spin-structure of QCD in planned polarized $pp$ collisions at RHIC.


title:
Supersymmetric Magnetic Moments Sum Rules and Spontaneous Supersymmetry
  Breaking

abstract:
  In supersymmetry the anomalous magnetic moment of particles belonging to the
same supermultiplet is related by simple sum rules. We study the modification
of these sum rules in the case of spontaneously broken N=1 global
supersymmetry.


title: Jet Physics at LEP and SLC

abstract:
  Experimental results on jet physics at LEP and SLC are reviewed and compared
with perturbative QCD predictions. The discussion includes determinations of
the strong coupling $\as$, measurements of event shape distributions and jet
cross sections, studies of subjet multiplicities and tests of QCD coherence.


title: Scale-Invariant Lipatov Kernels from t-Channel Unitarity

abstract:
  The Lipatov equation can regarded as a reggeon Bethe-Salpeter equation in
which higher-order reggeon interactions give higher-order kernels. Infra-red
singular contributions in a general kernel are produced by t-channel nonsense
states and the allowed kinematic forms are determined by unitarity. Ward
identity and infra-red finiteness gauge invariance constraints then determine
the corresponding scale-invariant part of a general higher-order kernel.


title: On the QCD corrections to $\Delta\rho$

abstract:
  We discuss some recent developments in the evaluation of the QCD corrections
to $\Delta\rho$, their interpretation, an estimate of the theoretical error,
and its effect on electroweak physics.


title: Kaon Condensation in Dense Stellar Matter

abstract:
  This talk is based on work done in collaboration with G.E. Brown and D.-P.
Min on kaon condensation in dense baryonic medium treated in chiral
perturbation theory using heavy-baryon formalism. It contains, in addition to
what was recently published, some new results based on the analysis on kaonic
atoms by Friedman, Gal and Batty and a discussion on a renormalization-group
analysis to meson condensation made together with H.K. Lee and Sin. Negatively
charged kaons are predicted to condense at the critical density $2\lsim
\rho/\rho_0\lsim 4$, in the range to allow all the intriguing new phenomena
predicted by Brown and Bethe to take place in compact star matter.


title: Color-Octet Fragmentation and the psi' Surplus at the Tevatron

abstract:
  The production rate of prompt $\psi'$'s at large transverse momentum at the
Tevatron is larger than theoretical expectations by about a factor of 30. As a
solution to this puzzle, we suggest that the dominant $\psi'$ production
mechanism is the fragmentation of a gluon into a $c \bar c$ pair in a pointlike
color-octet S-wave state, which subsequently evolves nonperturbatively into a
$\psi'$ plus light hadrons. The contribution to the fragmentation function from
this process is enhanced by a short-distance factor of $1/\alpha_s^2$ relative
to the conventional color-singlet contribution. This may compensate for the
suppression by $v^4$, where $v$ is the relative momentum of the charm quark in
the $\psi'$. If this is indeed the dominant production mechanism at large
$p_T$, then the prompt $\psi'$'s that are observed at the Tevatron should
almost always be associated with a jet of light hadrons.


title: Baryogenesis from a Lepton Asymmetric Universe

abstract:
  We demonstrate that $CP-$violation in the Majorana mass matrices of the heavy
neutrinos can generate a $CP-$asymmetric universe. The subsequent decay of the
Majorana particles generates a lepton number asymmetry. During the electroweak
phase transition the lepton asymmetry is converted into a baryon asymmetry,
which survives down to this time.


title:
Pure Leptonic Radiative Decays $B^\pm, D_s\to\ell\nu\gamma$ and the
  Annihilation Graph

abstract:
  Pure leptonic radiative decays of heavy-light mesons are calculated using a
very simple non-relativistic model. Dominant contribution originates from
photon emission from light initial quark. We find
$BR(B^\pm\to\ell\nu\gamma)\sim3.5\times10^{-6}$ and $BR(D_s\to
\ell\nu\gamma)\sim1.7 \times10^{-4}$. The importance of these reactions to
clarify the dynamics of the annihilation graph is emphasized.


title: Exclusive vector meson production at HERA

abstract:
  Exclusive vector meson production from real and virtual photons is, for the
most part, described well by soft pomeron exchange. However, there are some
unsolved normalisation problems, and just a hint that an additional
contribution from hard pomeron exchange may be needed.


title: Higgs search in e+e- and gamma-gamma colliders

abstract:
  The prospects for discovering Higgs particles and studying their fundamental
properties at future high--energy electron--positron and photon-photon
colliders are reviewed. Both the Standard Model Higgs boson and the Higgs
particles of its minimal supersymmetric extension are discussed. We also
comment on a two Higgs doublet model searches at LEP 1. We update various
results by taking into account the value of the top quark mass obtained by the
CDF Collaboration and by including radiative corrections.


title: Combining Vector-- and Heavy Quark Symmetry

abstract:
  Assuming that the chiral symmetry of the light degrees of freedom is realized
as the vector symmetry proposed by Georgi, we write down a chiral Lagrangian
for heavy mesons which incorporates both heavy quark and vector symmetry. Some
of the phenomenological implications of this idea are considered.


title: Polarization in Top Quark Production and Decay near Threshold

abstract:
  Theoretical results are presented for top quarks produced in annihilation of
polarized electrons on positrons. Polarization studies for $t\bar t$ pairs near
threshold are free from hadronization ambiguities. This is due to the short
lifetime of the top quark. Semileptonic decays are discussed as well as their
applications in studying polarization dependent processes involving top quarks.
The Green function formalism is applied to $t\bar t$ production at future
$e^+e^-$ colliders with polarized beams. Lippmann--Schwinger equation is solved
numerically for the QCD chromostatic potential given by the two-loop formula at
large momentum transfers and Richardson ansatz at intermediate and small ones.
The polarization dependent momentum distributions of top quarks and their decay
products are calculated.


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. We have
calculated the QCD radiative corrections to the color-singlet model of this
reaction. They are large at moderate photon energies, but decrease with
increasing energies. The cross section and the $J/\psi$ energy spectrum are
compared with the available fixed-target photoproduction data and predictions
are given for the HERA energy range.


title: A Model Independent Approach to Solar Neutrino Experiments

abstract:
  In the first part of this report we present the results of a model
independent analysis of the existing solar neutrino data. We obtained forbidden
regions in the plane of the parameters Delta m^2 and sin^2 2 theta in two
cases: A) Without any restrictions on the values of the solar neutrino fluxes
from different reactions; B) With some restrictions that take into account the
predictions of all the existing solar models. We show that the existing solar
neutrino data allow to exclude rather large regions in the plane of the
parameters Delta m^2 and sin^2 2 theta (especially in case B). In the second
part of this report we present a general method for the analysis of solar
neutrino data that can be applied to future solar neutrino experiments (SNO,
Super-Kamiokande, Icarus) in which high energy 8B neutrinos will be detected.
We show that these experiments will allow: 1) To reveal in a model independent
way the presence of sterile neutrinos in the flux of solar neutrinos on the
earth and to obtain lower bounds for the probability of transition of nu_e's
into sterile states; 2) To obtain directly from the experimental data the
initial 8B nu_e flux and the probability of nu_e's to survive (if there are no
transitions of nu_e's into sterile states).


title: Rare $K$ Decays

abstract:
  The rare decays of the $K$ meson have had a long tradition as a laboratory
for testing the symmetry properties of the weak interactions, and the manner in
which these symmetries are broken by higher order effects. Present--day
interest is focussed on decays that are suppressed by $CP$--symmetry or GIM
symmetry. Such decays, in the standard theory, are sensitive to effects of the
virtual top quark, and could also reveal new interactions transcending the
standard model. In addition, the radiative decays of the $K$ meson have become
a useful testing--ground for effective Lagrangians describing the low energy
interactions of pions, kaons and photons.


title: Zero Modes on Linked Strings

abstract:
  We study linked loops of string in the presence of bosonic condensates and
fermionic zero modes on the strings. We find that the strings necessarily carry
a current if the bosons have an Aharanov-Bohm interaction with the string. The
fermionic case is analyzed in the context of the standard model where there are
lepton and quark zero modes on $Z-$strings. Here we find that the fermionic
ground state in the linked string background is lower than the ground state
when the loops are unlinked but otherwise identical. As in the bosonic case,
the $Z-$strings carry a non-vanishing electric current in the ground state. The
baryon number of the linked configuration is found to agree with previous
indirect results. We also evaluate the angular momentum, electromagnetic charge
and baryonic three current on the linked $Z-$string configuration. Finally we
point out a possible gravitational analogue of the linked string system.


title: On the Nikolaev-Zakharov-Zoller form for the BFKL pomeron

abstract:
  The equation proposed by N.N.Nikolaev, B.G.Zakharov and V.R.Zoller for the
colour dipole cross-section is compared with the BFKL equation for the hard
pomeron for the $SU(2)$ colour group. It is demonstrated that for a fixed
coupling constant the difference between the two equations is due to a
different manner to introduce the gluon mass.


title: A determination of the QED coupling at the $Z$ pole

abstract:
  We critically examine the evaluation of the hadronic contribution to the
running of the QED coupling, $\alpha$, from $Q^2=0$ to $Q^2=M_Z^2$. Using data
for $e^+e^-\to{}$hadrons we find that $\alpha(M_Z^2)^{-1} = 128.99\pm 0.06$, as
compared to the existing value of $128.87\pm 0.12$.


title: Unification and low-energy supersymmetry at one and two-loop orders

abstract:
  The status of coupling constant unification -- assuming the validity of the
standard model or of its minimal supersymmetric extension at high energies --
and of relations between various Yukawa couplings (assuming the supersymmetri
extension) which are implied in certain grand-unified theories, are studied in
detail. Theoretical uncertainties in the calculations are emphasized, and
low-energy constraints and predictions are derived. In particular, we find that
bottom-tau unification favors a Higgs boson lighter than 110 GeV. The structure
of the vacuum in the model studied is also discussed. Implications of embedding
supersymmetric models in grand-unified theories are further explored and are
shown to affect the soft supersymmetry breaking mass parameters of the models,
and thus the spectrum at low-energy.


title: The Spectrum of the O(g^4) scale-invariant Lipatov Kernel

abstract:
  The scale-invariant $O(g^4)$ Lipatov kernel has been determined by t-channel
unitarity. The forward kernel responsible for parton evolution is evaluated and
its eigenvalue spectrum determined. In addition to a logarithmic modification
of the $O(g^2)$ kernel a distinct new kinematic component appears. This
component is infra-red finite without regularization and has the holomorphic
factorization property necessary for conformal invariance. It gives a reduction
(of ~$\sim 65\alpha_s^2/\pi^2\sim 0.15$) in the power growth of parton
distributions at small-x.


title:
Dynamics of Cosmological Phase Transitions: What Can We Learn from
  Condensed Matter Physics?

abstract:
  A brief outline is given of the description of phase transition kinetics in
condensed matter systems with a continuous symmetry, emphasising the roles of
dissipation, coarse-graining and scaling. The possible relevance of these ideas
to the early universe is explored in the contexts of the GUT string transition
and the electroweak transition.


title: SO(8) Colour as possible origin of generations

abstract:
  A possible connection between the existence of three quark-lepton generations
and the triality property of SO(8) group (the equality between 8-dimensional
vectors and spinors) is investigated.


title: Pionium in the elementary particle decays

abstract:
  Some atomic decays of elementary particles with pionium
($\pi^+\pi^-$-dimesoatom) in the final state are considered. Only for K-meson
atomic decays are the corresponding branching ratios big enough to make their
experimental study realistic. The $O(\alpha)$ order corrections to the lifetime
of pionium are also calculated.


title: Neutrino Oscillations from Discrete Non-Abelian Symmetries

abstract:
  I discuss a SUSY-GUT model with a non-Abelian discrete family symmetry that
explains the observed hierarchical pattern of quark and lepton masses. This
$SO(10) \times \Delta(75)$ model predicts modified quadratic seesaw neutrino
masses and mixing angles which are interesting for three reasons: i.) they
offer a solution to the solar neutrino problem, ii.) the tau neutrino has the
right mass for a cosmologically interesting hot dark matter candidate, and
iii.) they suggest a positive result for the $\nu_\mu \rightarrow \nu_\tau$
oscillation searches by the CHORUS and NOMAD collaborations. However, the model
shares some problems with many other predictive GUT models of quark and lepton
masses. Well-known and once successful mass and angle relations, such as the
$SU(5)$ relation $\lambda_b^{GUT}=\lambda_\tau^{GUT}$, are found to be in
conflict with the current experimental status. Attempts to correct these
relations seem to lead to rather contrived models.


title: Hadronization

abstract:
  Hadronization corrections to the predictions of perturbative QCD are
reviewed. The existing models for the conversion of quarks and gluons into
hadrons are summarized. The most successful models give a good description of
the data on $e^+e^-$ event shapes and jet fragmentation functions, and suggest
that the dominant hadronization effects have a $1/Q$ dependence on the hard
process energy scale $Q$. In several cases the $1/Q$ terms can be understood in
terms of a simple longitudinal phase-space model. They can also be inferred by
relating non-perturbative renormalon effects to the infrared cutoff dependence
of perturbative contributions.


title: Testing the Standard Model of CP Violation in the B System

abstract:
  We review the subject of CP violation in the $B$ meson system within the
Standard Model of CP violation, which is based on a complex phase in the
Cabibbo-Kobayashi-Maskawa (CKM) matrix. Three kinds of CP nonconservation are
studied: In $B^0-\Bbar$ mixing, in mixed neutral $B$ decays to states which are
common decay products of $B^0$ and $\Bbar$ and in direct decays of charged $B$
mesons. Measurements of certain CP asymmetries are shown to determine the three
angles of the CKM unitarity triangle. $\beta$ is measured cleanly in
$B^0\to\psi K_S$. Uncertainties due to penguin amplitudes in the determination
of $\alpha$ using the asymmetry in $B^0\to \pi^+\pi^-$ (or $B^0 \to
\rho^+\pi^-$) can be eliminated (or in the worst case only estimated) by
relating the rate of this process to decay rates involving other two light
pseudoscalars. The angle $\gamma$ can be measured in charged $B$ decays,
provided that color suppression in $B\to DK$ (or $B\to DK_i(1400)$) is not too
strong and/or that certain rescattering effects in $B$ decays to two light
pseudoscalars are not too large.


title:
A Note on the QCD Corrections to Forward--Backward Asymmetries of
  Heavy--Quark Jets in Z Decays

abstract:
  The measurement of the forward-backward asymmetries of heavy quarks provides
one of the most precise determinations of $\sin^2\theta_W$ in $Z$ decays. We
discuss in detail the one--loop QCD radiative corrections to these asymmetries.
Results are given for single heavy--quark jet asymmetries and asymmetries of
the thrust axis, as well as for heavy--quark two--jet final states.}


title: Biased discrete symmetry and domain wall problem

abstract:
  We reconsider a cosmological evolution of domain walls produced by
spontaneous breaking of an approxime discrete symmetry. We show, that domain
walls may never collapse even if the standard bound on the vacuum energy
asymmetry is satisfied. Instead of disappearing, these defects may form stable
``bound states'' - double wall systems. Possible stability of such a wall is a
dynamical question and consequently restricts the allowed range of parameters.
In particular, in the two Higgs doublet standard model with an anomalous Z(2)
symmetry, the above restriction suggests the mass of the pseudoscalar Higgs
(would be axion) being close to the mass of the scalar one.


title:
Constraints on the electroweak universal parameters and the top and
  Higgs masses from updated LEP/SLC data

abstract:
  A global analysis is performed using the latest data from LEP and SLC.
Constraints on the electroweak universal parameters ($S,T,U$) and on the masses
of the top quark and Higgs boson within the Standard Model (SM) are
investigated. The uncertainties due to the QCD and QED effective couplings,
$\alpha_s(\mz)$ and $\bar{\alpha}(\mmz)$, are examined in detail. Even though
the mean value of $S$ is increased to be consistent with zero, the naive
Technicolor models are still disfavored due to its reduced error. Within the
SM, we find the 90\,\%CL constraints; $133\gev<m_t<190\gev$ and
$10\gev<\mh<440\gev$ for $\alpha_s(\mz)=0.116$ and $1/\bar{\alpha}(\mmz)
=128.72$. The experimental constraints on the $\zbb$ vertex form-factor,
$\delb(\mmz)$, play an important role in disfavoring the region of large
$m_t(m_t \sim 200\gev)$ and large $\mh(\mh \sim 1000\gev)$. If $m_t$ is
precisely known, the present electroweak data give a rather strict upper bound
on the Higgs mass, $\mh<140\,(300)\gev\,$ at 95\%~CL, for $m_t=160\, (175)\gev$
and for the above $\alpha_s(\mz)$ and $\bar{\alpha}(\mmz)$.


title: CP and CPT measurements at DAFNE

abstract:
  Starting from the time evolution of the C-odd $\bar{K}^0 K^0$ system, we
analyze the asymmetries measurable at DAFNE and their implications on CP
violation and on the possible tests of T and CPT symmetries. In particular the
ratio $\epsilon'/\epsilon$ can be measured with high precision (up to about
$10^{-4}$ for the real part). The CP-, T- and CPT-violating parameters can be
explored in $K_S$ semileptonic decays with an accuracy of the order of
$10^{-3}$. The possibility to detect $K_S \to 3 \pi$ and $K_L \to \pi \pi
\gamma$ decays is also discussed.


title: A novel left-right symmetric model

abstract:
  A novel gauge model which has a spontaneously broken parity symmetry is
constructed. The model has only 2 parameters beyond those of the standard
model. Some of the unusual implications of the model are discussed.


title:
Characteristics of QCD Phase Transitions in an Extended Skyrme Model on
  $S^3$

abstract:
  We study the characteristics of the QCD phase transitions in dense hadronic
matter using the Skyrme model constructed on S^3. We find numerically the
localized solutions on $S^3$ using the extended Skyrme model which implements
correctly the scale symmetry of QCD. The transition from the localized phase to
the delocalized phase is found to be of first order at the critical radius of
the hypersphere, $L_c$. The chiral restoration and the gluon decondensation
also take place at the same critical size.


title: Bounds on Scalar Leptoquarks from Z Physics

abstract:
  We analyse the constraints on scalar leptoquarks coming from radiative
corrections to $Z$ physics. We perform a global fitting to the LEP data
including the contributions of the most general effective Lagrangian for scalar
leptoquarks, which exhibits the $SU(2)_L \times U(1)_Y$ gauge invariance. We
show that the bounds on leptoquarks that couple to the top quark are much
stronger than the ones obtained from low energy experiments.


title: Chiral Effective Theory for Heavy Mesons

abstract:
  I review recent developments in the description of the interactions between
light and heavy mesons by an effective chiral lagrangian having the symmetries
of the Heavy Quark Effective Theory. In particular the problem of the
determination of the strong coupling constants $g_{P^* P \pi}$ and $g_{P^* P
\rho}$ ($P, P^*=$ heavy mesons) is addressed. Invited talk given at the 18th J.
Hopkins Workshop (Florence, September 1994)


title:
Four-Fermi Operators in $e^+$ $e^-$ Annihilation Experiments and
  Uncertainties in $Z$ Boson Properties

abstract:
  We investigate the effects of possible new four-Fermi operators on $e^+$
$e^-$ annihilation experiments. They represent a class of new physics, which
has the potential to change the parameters of the $Z$ boson and at the same
time interferes with their determination from the data. We show that in the
presence of such operators the $Z$ parameters obtained from lineshape fits can
change significantly. Another important property of these operators is that
they spoil the factorization of the expression for the left-right asymmetry,
$A_{LR}$, into initial and final state couplings. Factorization and subsequent
cancellation of the final state coupling occurs in the Standard Model (after
correcting for photonic amplitudes) and is crucial for the interpretation of
$A_{LR}$ as a measurement of the effective weak mixing angle. Four-Fermi
operators may thus provide an explanation for the high value of the
polarization asymmetry as observed at SLC. However, the data from lower energy
$e^+$ $e^-$ annihilation severely constrains this class of operators and
virtually closes this possible loophole on how new physics might explain the
SLC/LEP discrepancy. We point out that if the surplus of observed $b$-pairs at
LEP is real and caused by these operators, there may be a significant effect on
the forward-backward asymmetry into $b$-quarks. It is this quantity which
presently gives the most precise determination of the weak mixing angle. We
present compact analytical expressions for the treatment of initial state
radiation in the presence of new contact operators.


title: Polarization in Top Quark Pair Production near Threshold

abstract:
  The polarization dependent momentum distributions of top quarks and their
decay products are calculated for $t\bar t$ production at future $e^+e^-$
colliders with polarized beams. The Green function formalism is applied to this
reaction near energy threshold. The Lippmann--Schwinger equations for the
$S$-wave and $P$-wave Green functions are solved numerically for the QCD
chromostatic potential given by the two-loop formula at large momentum
transfers and Richardson ansatz at intermediate and small ones. It is
demonstrated that for the longitudinally polarized electron beam an optimally
polarized sample of top quarks can be produced.


title: Overview of the Standard Model

abstract:
  A brief overview is presented of the standard model of electroweak
interactions, including precision tests, the role of the
Cabibbo-Kobayashi-Maskawa (CKM) matrix in describing CP violation, windows on
intermediate-scale physics, and the nature of the Higgs phenomenon.


title:
Supersymmetric Models with a Gauge Singlet and Non-Universal Soft Terms
  from Orbifold String Theory

abstract:
  The particle spectrum of the supersymmetric extension of the standard model
with a gauge singlet is studied. Soft supersymmetry breaking terms are
explicitly chosen to be non-universal according to orbifold string theory. they
depend on modular weights of chiral fields and on an angle $\theta$ specifying
the supersymmetry breaking sector. Imposing radiative weak symmetry breaking
and requiring that standard model Yukawa couplings should be allowed yield
constraints on modular weights and almost specifies the angle $\theta$. We then
perform a numerical anlysis of the low energy spectrum. It turns out that the
spectrum is very constrained, revealing salient features such as light Higgses
and neutralinos. The latter turns out to be essentially gaugino-like.


title: CP violation at colliders

abstract:
  The prospects of experimental detection of $CP$ violation at $e^+e^-$ and
$pp/p\overline{p}$ colliders are reviewed. After a general discussion on the
quantities which can measure $CP$ violation and on the implications of the
$CPT$ theorem, various possibilities of measuring $CP$ violation arising
outside the standard model are taken up. $CP$ violation in leptonic processes,
especially polarization effects in $e^+e^-\rightarrow l^+l^-$ are discussed
next. $CP$ violation in $t\overline{t}$ and $W^+W^-$ production and decay is
also described. (Based on talk presented at the WHEPP3, Madras, January 1994).


title:
Measurement of the $\tau$ electric dipole moment using longitudinal
  polarization of $e^+e^-$ beams

abstract:
  Certain CP-odd momentum correlations in the production and subsequent decay
of $\tau$ pairs in $e^+ e^-$ collisions are enhanced significantly when the
$e^+$ and $e^-$ beams are longitudinally polarized. These may be used to probe
the real and imaginary parts of $d_\tau^\gamma$, the electric dipole moment of
the $\tau$. Closed-form expressions for these ``vector correlations'' and the
standard deviation of the operators defining them due to standard model
interactions are presented for the two-body final states of $\tau$ decays. If
42\% average polarization of each beam is achieved, as proposed for the
tau-charm factories, with equal integrated luminosities for each sign of
polarization and a total yield of $2\cdot 10^7$ $\tau^+ \tau^-$ pairs, it is
possible to attain sensitivities for $\vert\delta {\rm Re}
d_{\tau}^{\gamma}\vert$ of $8\cdot 10^{-19}$, $1\cdot 10^{-19}$, $1\cdot
10^{-19}$ $e$ cm respectively and for $\vert\delta {\rm Im}
d_{\tau}^{\gamma}\vert$ of $4\cdot 10^{-14}$, $6\cdot 10^{-15}$, $5\cdot
10^{-16}$ $e$ cm respectively at the three operating center-of-mass energies of
3.67, 4.25 and 10.58 GeV. These bounds emerge when the effects of a posible
weak dipole form factor $d_\tau^Z$ are negligible as is the case when it is of
the same order of magnitude as $d_\tau^\gamma$. Furthermore, in such a
polarization experiment where different polarizations are possible, a
model-independent disentangling of their individual effects is possible, and a
technique to achieve this is described. A strong longitudinal polarization
physics programme at the tau-charm factory appears warranted.


title: Baryogenesis at the Electroweak Scale

abstract:
  The generation of the baryon asymmetry of the universe is considered in the
standard model of the electroweak theory with simple extensions of the Higgs
sector. The propagation of quarks of masses up to about 5 GeV are considered,
taking into account their markedly different dispersion relations due to
propagation through the hot electroweak plasma. It is shown that the
contribution of these lighter quarks to the baryon asymmetry can be comparable
to that for the t quark considered earlier.


title: Electroweak Flavor-Conserving Gauge Processes: Virtual Effects

abstract:
  Summary of electroweak Standard Model, including aspects of gauge summetry,
symmetry breaking, and quantum radiative corrections. Implications of precise
electroweak measurements for Standard Model and hypothetical non-Standard
states and interactions. Status of exact and approximate symmetries of the
Standard Model. The minimal electroweak Standard Model satisfies the present
data well, if the effect of the known top quark mass is included. Contribution
to the APS/DPF Drell Panel Study of American High Energy Physics.


title: Meson Correlators in QCD Vacuum - is Saturation the Right Approach ?

abstract:
  Equal time, point to point correlation functions for spatially separated
meson currents are calculated with respect to a variational construct for the
ground state of QCD. With exact calculations, vector, axial vector and scalar
channels show qualitative agreement with the phenomenological predictions,
where as pseudoscalar channel does not. However, the pseudoscalar correlator,
when approximated by saturating with intermediate one pion states agrees with
results obtained from spectral density functions parametrised by pion decay
constant and $<\bar \psi \psi>$ value obtained from chiral perturbation theory.


title:
Bounds on the Higgs Mass in the Standard Model and Minimal
  Supersymmetric Standard Model

abstract:
  We present bounds on the Higgs mass in the Standard Model and in the Minimal
Supersymmetric Standard Model using the effective potential with
next-to-leading logarithms resummed by the renormalization group equations, and
physical (pole) masses for the top quark and Higgs boson. In the Standard Model
we obtain lower bounds from stability requirements: they depend on the top mass
and the cutoff scale. In the Minimal Supersymmetric Standard Model we obtain
upper bounds which depend on the top mass and the scale of supersymmetry
breaking. A Higgs mass measurement could discriminate, depending on the top
mass, between the two models. Higgs discovery at LEP-200 can put an upper bound
on the scale of new physics.


title:
Tests of the Parton Model for Inclusive Semileptonic B Decays with the
  Heavy Quark Effective Theory

abstract:
  In order to study the end-point spectrum of inclusive semileptonic $b
\rightarrow u$ decays, we investigate the parton model motivated by deep
inelastic scattering process. The reliability of the model is carefully
examined by comparing the decay rates and the lepton spectra for $b \rightarrow
c$ decay with those of the heavy quark effective theory. We also compute the
decay rates of the inclusive semileptonic decay into tau lepton in terms of the
parton model, which give another test of the model independently. We conclude
that one can make the parton model consistent with the heavy quark effective
theory, and it would be phenomenologically useful in extracting $|V_{ub}|$.


title: Charged Higgs Effects on Exclusive Semi-tauonic $\bbox{B}$ Decays

abstract:
  We study effects of charged Higgs boson exchange in the $B$ semileptonic
decays $\bar B \rightarrow D^{(*)}\tau\bar\nu_\tau$. Both branching ratio and
$\tau$ polarization are examined. We use the recent experimental data on
semileptonic $B$ decays and the heavy quark effective theory in order to reduce
theoretical uncertainty in the hadronic form factors. Theoretical uncertainty
in the branching ratio is found to be rather small and that in the $\tau$
polarization is almost negligible. Their measurements will give nontrivial
constraints on the charged Higgs sector.


title: The strong-CP question in SU(3)_c X SU(3)_L X U(1)_N models

abstract:
  We analyze two recent models based on the gauge group
SU(3)$_c\times$SU(3)$_L\times$U(1)$_N$ where each generation is not
anomaly-free, but anomaly cancels when three generations are taken into
account. We show that the most general Yukawa couplings of these models admit
of a Peccei-Quinn symmetry. This symmetry can be extended to the entire
Lagrangian by using extra fields in a very elegant way so that the resulting
axion can be made invisible.


title: Two-Doublet Higgs Structure at the Electroweak Energy Scale

abstract:
  The existence of supersymmetry above a few TeV and that of two Higgs doublets
at the electroweak energy scale do not necessarily result in the minimal
supersymmetric standard model (MSSM). An interesting counter example is given
with m_h < 2^{1/2} m_W + radiative corrections = 145 GeV instead of m_h < m_Z +
radiative corrections = 128 GeV in the MSSM.


title: Left-Right Gauge Symmetry at the TeV Energy Scale

abstract:
  Two first examples beyond the standard model are given which exhibit
left-right symmetry (g_L = g_R) and supersymmetry at a few TeV, together with
gauge-coupling unification at around 10^{16} GeV.


title: Induced Gluon Radiation in a QCD Medium

abstract:
  Soft gluon radiation induced by multiple scattering of a fast quark or gluon
propagating through QCD matter is discussed. After revisiting the
Landau-Pomeranchuk-Migdal effect in QED we show that large formation times of
bremsstrahlung quanta determine the QCD radiation intensity (in analogy to QED)
and derive the gluon energy spectrum. Coherent suppression takes place as
compared to the Bethe-Heitler situation of independent emissions. As a result
the energy loss of fast partons in a QCD medium depends on the incident energy
$E$ similarly to QED, $-dE/dz \propto \sqrt{E}$.


title: Bubble Nucleation Rate In Fourth-Order Gravity

abstract:
  We calculate the bubble nucleation rate in a fourth-order gravity theory
whose action contains an $R^2$ term, under the thin-wall approximation, by two
different methods. First the bounce solution is found for the Euclidean version
of the original action. Next, we use a conformal transformation to transform
the theory into general relativity with an additional scalar field and then
proceed to find the bounce solution. The same results are obtained from both
calculations.


title: Fermions on the Electroweak String

abstract:
  We construct a simple class of exact solutions of the electroweak theory
including the naked $Z$--string and fermion fields. It consists in the
$Z$--string configuration ($\phi,Z_\theta$), the {\it time} and $z$ components
of the neutral gauge bosons ($Z_{0,3},A_{0,3}$) and a fermion condensate
(lepton or quark) zero mode. The $Z$--string is not altered (no feed back from
the rest of fields on the $Z$--string) while fermion condensates are zero modes
of the Dirac equation in the presence of the $Z$--string background (no feed
back from the {\it time} and $z$ components of the neutral gauge bosons on the
fermion fields). For the case of the $n$--vortex $Z$--string the number of zero
modes found for charged leptons and quarks is (according to previous results by
Jackiw and Rossi) equal to $|n|$, while for (massless) neutrinos is $|n|-1$.
The presence of fermion fields in its core make the obtained configuration a
superconducting string, but their presence (as well as that of
$Z_{0,3},A_{0,3}$) does not enhance the stability of the $Z$--string.


title: Momentum dependent quark mass in two-point correlators

abstract:
  A momentum dependent quark mass may be incorporated into a quark model in a
manner consistent with dynamically broken chiral symmetry. We use this to study
the high $Q^2$ behavior of the vector, axialvector, scalar and pseudoscalar
two-point correlation functions. Expanding the results to order $1/Q^6$, we
show the correspondence between the dynamical quark mass and the vacuum
condensates which appear in the operator product expansion of QCD. We recover
the correct leading logarithmic $Q^2$ dependence of the various terms in the
OPE, but we also find substantial subleading corrections which are numerically
huge in a specific case. We conclude by using the vector minus axialvector
correlator to estimate the $\pi^+ - \pi^0$ electromagnetic mass difference.


title:
Fermion mass hierarchies in low energy supergravity and superstring
  models

abstract:
  We investigate the problem of the fermion mass hierarchy in supergravity
models with flat directions of the scalar potential associated with some gauge
singlet moduli fields. The low-energy Yukawa couplings are nontrivial
homogeneous functions of the moduli and a geometric constraint between them
plays, in a large class of models, a crucial role in generating hierarchies.
Explicit examples are given for no-scale type supergravity models. The Yukawa
couplings are dynamical variables at low energy, to be determined by a
minimization process which amounts to fixing ratios of the moduli fields. The
Minimal Supersymmetric Standard Model (MSSM) is studied and the constraints
needed on the parameters in order to have a top quark much heavier than the
other fermions are worked out. The bottom mass is explicitly computed and shown
to be compatible with the experimental data for a large region of the parameter
space.


title:
Limits on Electron-Neutrino Oscillations from the GALLEX $^{51}$Cr
  Source Experiment

abstract:
  The recent result from the chromium source experiment carried out by the
GALLEX collaboration implies interesting limits on the parameters $\Delta m^2$
and $\sin^22\theta$ describing neutrino oscillations. Values of $\Delta
m^2~>~0.17$ eV$^2$ for maximal mixing and of $\sin^22\theta > 0.38$ for $\Delta
m^2 > 1$~eV$^2$ are ruled out at 90\% C.L. This result improves by more than an
order of magnitude previous limits on $\Delta m^2$ derived from
electron-neutrino oscillation experiments at accelerators.


title: Multi-Pion Correlation Effects on Two-Pion Interferometry

abstract:
  A general derivation of the multi-pion correlation function for completely
chaotic source is given. Its effects on the pion multiplicity distribution,
two-pion interferometry are studied. A generalized multi-pion correlation
function for a partially coherent source is also discussed.


title:
Renormalization-Group Flow Analysis of Meson Condensations in Dense
  Matter

abstract:
  We present a renormalization-group (RG) flow argument for s-wave kaon
condensation in dense nuclear-star matter predicted in chiral perturbation
theory. It is shown that it is the {\it relevant} mass term together with {\it
any} attractive interaction for the kaon in medium that triggers the
instability. We show that a saddle point of multi-dimensional RG flow can imply
a phase transition. Pion condensation is also analyzed along the same line of
reasoning.


title: On Instanton Contributions to the tau Hadronic Width

abstract:
  Comparing the results of finite energy and Borel transformed sum rules for
the difference of vector and axial vector current correlators we evaluate the
instanton contributions to the $\tau$ hadronic width. In contrast to an
explicit theoretical calculation we find that the instanton contributions to
the $\tau$ hadronic width are much smaller than the standard nonperturbative
corrections.


title:
Semileptonic tau decays, structure functions, kinematics and
  polarisation

abstract:
  The most general angular distribution of two or three meson final states from
semileptonic decays $\tau\rightarrow \pi\pi\nu$, $K\pi\nu$, $\pi\pi\pi\nu$,
$K\pi\pi\nu$, $K\pi\nu$, $KKK\nu$, $\eta\pi\pi\nu,\,\ldots{}$ of polarized
$\tau$ leptons can be characterized by 16 structure functions. Predictions for
hadronic matrix elements, based on CVC and chiral Lagrangians and their
relations to the structure functions are discussed. Most of them can be
determined in currently ongoing high statistics experiments. Emphasis of the
kinematical analysis is firstly put on $\tau$ decays in $e^{+}e^{-}$
experiments where the neutrino escapes detection and the $\tau$ rest frame
cannot be reconstructed. Subsequently it is shown, how the determination of
hadron tracks in double semileptonic events allows to fully reconstruct the
$\tau$ kinematics. The implications for the spin analysis are indicated.


title: Lepton-Quark Masses and Democratic Symmetry

abstract:
  It is shown that the simplest breaking of the subnuclear democracy leads to a
successful description of the mixing between the second and third family. In
the lepton channel the nu_mu - nu_tau -oscillations are expected to be
described by a mixing angle of 2.65 degrees which might be observed soon in
neutrino experiments.


title: Effective Lagrangians for Light Quarks

abstract:
  The class of phenomenological Lagrangians used for light constituent quarks
is discussed. The Nambu-Jona-Lasinio model is then argued to be a good
phenomenological choice and the quality of its prediction in the purely
hadronic sector including several relations between parameters illustrated.
Then we use these models to calculate nonleptonic matrix elements. The
$\pi^+-\pi^0$ mass difference and the $B_K$ parameter, relevant in
$K^0-\overline{K}^0$ mixing, are treated in more detail.


title: Extended Chiral Transformations Including Diquark Fields as Parameters

abstract:
  We introduce extended chiral transformation, which depends both on
pseudoscalar and diquark fields as parameters and determine its group
structure. Assuming soft symmetry breaking in diquark sector, bosonisation of a
quasi-Goldstone $ud$-diquark is performed. In the chiral limit the $ud$-diquark
mass is defined by the gluon condensate, $m_{ud}\approx 300 MeV$. The diquark
charge radius is $\langle r^2_{ud}\rangle^{1/2}\approx 0.5 fm$.


title:
Soft Gluon Suppression of $ 1/N_{c} $ Contributions in Color Suppressed
  Heavy Meson Decays

abstract:
  We discuss the non-factorizable terms in color suppressed (Class II) decays.
Our emphasis is on the non-perturbative soft gluon exchange mechanism, which
has been previously found to be responsible for the rule of discarding $
1/N_{c} $ in the Class I decays. The non-factorizable contribution to the
decays $ \bar{B}^{0} \rightarrow D^{0} \pi^{0} $ at the tree level is estimated
within the light cone QCD sum rule method which combines the technique of the
QCD sum rules with the description of the pion in terms of the set of wave
functions of increasing twist. We find that the same soft gluon exchange
mechanism tends to cancel the $ 1/N_{c} $ term in the factorized amplitude.


title: $\tau \to \pi K \nu$ Decay and $\pi K$ Scattering

abstract:
  Using chiral low energy theorems and elastic unitarity assumption, the
$\tau\to\pi K \nu $ decay is investigated. The vector and scalar $\pi K$ form
factors are calculated. It is found that the $\pi K$ spectrum is dominated by
the $K^*$ resonance. By measuring the forward-backward asymmetry, it is shown
that the S wave $\pi K$ phase shift can be determined near the $K^{*}$
resonance region. The calculated branching ratio and resonance parameters are
in good agreement with experiments.


title:
Application of Current Algebra in Three Pseudoscalar Meson Decays of
  $\tau$ Lepton

abstract:
  The decays of $\tau \to 3\pi \nu $ and $\tau \to \pi K^{*} \nu, K\rho \nu $
are calculated using the hard pion and kaon current algebra and assuming the
Axial-Vector meson dominance of the hadronic axial currents. Using the
experimental data on their masses and widths, the $\tau$ decay branching ratios
into these channels are calculated and found to be in a reasonable agreement
with the experimental data. In particular, using the available Aleph data on
the $3\pi$ spectrum, we determine the $A_1$ parameters, $m_A=1.24\pm 0.02 GeV$,
$\Gamma _A=0.43\pm 0.02$ GeV; the hard current algebra calculation yields a
$3\pi$ branching ratio of $19 \pm 3 \%$.


title: Supersonic String Model for Witten Vortices

abstract:
  A new cosmic string model specified by two independent mass parameters is
introduced for the purpose of providing a realistic representation of the
macroscopic dynamical behaviour of Witten type (superconducting) vortex defects
of the vacuum. Unlike the self dual single mass parameter models previously
used for this purpose, the new model successfully represents the effect of
current saturation and the feature that wiggle propagation remains supersonic
even in the weak current limit.


title: Topcolor Assisted Technicolor

abstract:
  A condensate, $\overline{t}t$, arising from $O(TeV)$ scale ``topcolor,'' in
addition to technicolor (and ETC) may naturally explain the gauge hierarchy,
the large top quark mass, and contains a rich system of testable consequences.
A triplet of strongly coupled pseudo--Nambu--Goldstone bosons, ``top-pions,''
near the top mass scale is a generic prediction of the models. A new class of
technicolor schemes and associated phenomenology is suggested in this approach.


title: The current of fermions scattered off a bubble wall

abstract:
  Proceeding from WKB quantization conditions, we derive a semiclassical
expression for the current of fermions scattered off a propagating bubble wall
in the presence of longitudinal gauge field. It agrees with the expression used
by Nasser and Turok in semiclassical analysis of instability of electroweak
bubble walls with respect to longitudinal $Z$ condensation. We discuss the
resulting dispersion relation for longitudinal $Z$ field and show that light
species are important for the analysis of stability, because of their large
contribution to plasma frequency.


title: QCD sum rules and chiral logarithms

abstract:
  Standard QCD sum-rule analyses of the nucleon mass give results that are
inconsistent with chiral perturbation theory due to an overly simple continuum
ansatz on the phenomenological side of the sum rule. We show that a careful
treatment of the continuum, including $\pi$-$N$ states and other states with
virtual pions, resolves the inconsistency associated with chiral logs.


title: Some Phenomenological Implications of String Loop Effects

abstract:
  We investigate low energy implications of string loop corrections to
supergravity couplings which break a possible flavor universality of the tree
level. If Supersymmetry is broken by the dilaton $F$-term, universal soft
scalar masses arise at the leading order but string loop corrections
generically induce flavor-non-diagonal soft terms. Constraints from flavor
changing neutral currents (FCNC) and CP violation then require a large
supersymmtery breaking scale and thus heavy gluinos and squarks. If
Supersymmetry is broken by moduli $F$-terms, universality at the string tree
level can only be guaranteed by extra conditions on the K\"ahler potential. A
large hierarchy between the gluino and squark masses ensures that FCNC and CP
violation constraints are satisfied. If the soft scalar masses vanish at the
string tree level, the cosmological problems related to light moduli can be
evaded. However, generic string loop corrections violate FCNC bounds and
require very heavy squark masses ($\approx 100\, TeV$).


title: Kaon Condensation in the Bound-State Approach to the Skyrme Model

abstract:
  We explore kaon condensation using the bound-state approach to the Skyrme
model on a 3-sphere. The condensation occurs when the energy required to
produce a $K^-$ falls below the electron fermi level. This happens at the
baryon number density on the order of 3--4 times nuclear density.


title:
Rates for Inclusive Deep-Inelastic Electroproduction of Charm Quarks at
  HERA

abstract:
  The coefficient functions for heavy-flavour production in deeply inelastic
electron-hadron scattering have been calculated previously. Analytic
expressions are impossible to publish due to their length. Therefore we have
tabulated them as two-dimensional arrays as is often done for the
scale-dependent parton densities. Using this computer program we present event
rates for charm production at HERA in bins of $x$ and $Q^2$. These rates are
insensitive to variations in the factorization and renormalization scale $\mu$.


title: Gamma--Ray Bursters, Neutrinos, and Cosmology

abstract:
  Gamma ray burst (GRB) objects are now widely thought to be at cosmological
distances, and thus represent enormous energy emission. Gamma ray spectra
extending to $GeV$ energies suggest the possiblity of accompanying neutrino
emission, and there are several models proposed suggesting the potential
detectability of such coincident neutrino bursts. With this in view, we examine
possible measurements that might be conducted to give experimental data useful
for astronomy, for cosmology and also neutrino properties. Of interest to
astronomy and cosmology, we show how measurement of neutrino flavor ratios
yields information on the nature and relative distance of the source. We point
out that cosmological time dilation might be measured for these sources using
neutrinos, as has been done for photons, and that neutrino oscillation lengths
in the range of $1$ to $10^5~Mpc$ can be probed with GRB neutrinos. We thus
note that these sources may make possible the first non-electromagnetic
measurements of the scale size of the universe. We discuss tests of the weak
equivalence principle, tests for flavor dependent gravitational couplings, and
tests for long time scale variation of physical constants. We also show that a
number of new bounds on neutrino properties (charge, mass, speed, lifetime)
could be facilitated to levels well beyond those already inferred from the
neutrino observation of SN1987A. We also examine the implications of these
physics opportunities for designers of neutrino telescopes. We conclude that
detection may be possible in planned instruments if the spectra are power law
extending to the $TeV$ energy region, and if the neutrino fluxes are equal to
or greater than the gamma ray fluxes. We emphasize the importance of low energy
detection in future experiments


title: Quenched Chiral Perturbation Theory for Heavy-Light Mesons

abstract:
  Quenched chiral perturbation theory is extended to include heavy-light
mesons. Non-analytic corrections to the decay constants, Isgur-Wise function
and masses and mixing of heavy mesons are then computed. The results are used
to estimate the error due to quenching in lattice computations of these
quantities. For reasonable choices of parameters, it is found that quenching
has a strong effect on $f_{B_s}/f_B$, reducing it by as much as $28\%$. The
errors are essentially negligible for the Isgur-Wise function and the mixing
parameter.


title: The F/D Ratios of Spin-flip Baryon Vertex in 1/N_c Expansion

abstract:
  We calculate the $F/D$ ratios of spin 1/2 baryon vertex for both the
non-relativistic quark model and the chiral soliton model with arbitrary number
of color degrees of freedom $N_c$ and examine the results in terms of the
consistency condition approach for the baryon vertices recently developed by
Dashen, Jenkins and Manohar from the viewpoint of QCD. We show that the $1/N_c$
corrections have two different origins, i.e. one is from the baryon states or
baryon wave functions and the other from the vertex operators. Although in the
limit of $N_c \to \infty$ the $F/D$ tends to 1/3 in all models, the $1/N_c$
expansion of $F/D$ ratio does not converge for $N_c=3$ in the chiral soliton
model in contrast to the non-relativistic quark model.


title: Observing Virtual LSPs at LEP II

abstract:
  In the minimal supersymmetric extension of the Standard Model (MSSM) with
$R$-parity conservation the possibility that the sneutrino and the second
lightest neutralino decay dominantly into invisible channels and, in addition
to the lightest neutralino, carry missing energy, is still open --- both
theoretically and experimentally. It is shown that for a large region of the
parameter space allowed by {\rm LEP-I} data, these particles can contribute
significantly to the process $e^+ e^- \longrightarrow \gamma$ + {\rm nothing}.
This signal, if it exists, can be easily detected at {\rm LEP-II} as an
enhancement over the Standard Model or the conventional MSSM predictions.


title: A general framework with two Higgs doublets and suppressed FCNC

abstract:
  We investigated a general framework of the Standard Model with two Higgs
doublets (2HDSM) with suppressed flavor-changing neutral currents (FCNC's).
Loop-induced FCNC (and CP-violating) effects, when confronted with experimental
constraints for the $K$-$\bar K$, $B$-$\bar B$ and $D$-$\bar D$ mixing and for
the $(b \to s \gamma)$ decay, provide us with constraints on the values of the
dominant Yukawa couplings of the charged Higgs, i.e., the values of the
couplings of $H^{\pm}$ to $t$ and $b$ quarks. Once these {\it low} energy
experimental data relevant for the mixings and for the mentioned decay, as well
as the theoretical uncertainties for the hadronic matrix elements, are
sufficiently reduced, such analyses may be able to rule out the minimal SM and
even certain special types of the 2HDSM's (e.g., the popular ``type II'', and
``type I'' 2HDSM). In such a case, a more general 2HDSM framework discussed
here could still survive as a viable framework. Eventual detection of the
charged Higgs in high energy experiments and the measurement of its mass would
represent important information that would additonally help to rule out or to
favor the various specific 2HDSM scenarios that are contained in the discussed
2HDSM framework.


title: Change with energy of source geometry as seen in hadron interferometry

abstract:
  The variation of radii, lifetimes, correlation lengths and the chaoticity
parameter of particle sources with the collision energy $\sqrt{s}$ is studied
by analysing and comparing two-particle Bose-Einstein correlation data obtained
by the NA22 Collaboration at $\sqrt{s}=22\ GeV$ and by the UA1-Minimum-Bias
Collaboration at $\sqrt{s}=630\ GeV$. The UA1-data are found to be inconsistent
with a static source, whereas both the data at $\sqrt{s}=22\ GeV$ and at $630\
GeV$ can be described in an expanding source model. In the latter model, the
$s$-dependence of the data implies an increase of the transverse radius with
$s$ and a decrease of the correlation lengths in longitudinal and in transverse
direction. The chaoticity parameter increases or remains approximately constant
as a function of the CM energy.


title: Heavy Quark Production in pp Collisions

abstract:
  A systematic study of the inclusive single heavy quark and heavy-quark pair
production cross sections in pp collisions is presented for RHIC and LHC
energies. We compare with existing data when possible. The dependence of the
rates on the renormalization and factorization scales is discussed. Predictions
of the cross sections are given for two different sets of parton distribution
functions.


title: Radiative Non-Leptonic Kaon Decays

abstract:
  We investigate to what extent DA$\Phi$NE will be able to test the Standard
Model in the confinement regime with radiative kaon decays. We concentrate on
processes which can be detected at DA$\Phi$NE and we review briefly those
decays where only upper limits can be expected. The Standard Model predictions
for these decays are analyzed in the framework of chiral perturbation theory.


title: Thermal Self-Energies at Zero Momentum

abstract:
  In general the zero momentum limit of thermal self-energies calculated in
perturbation theory depends on the order in which the time and the space
components of the momentum are taken to zero. We show that this is an artifact
of the perturbative calculation, and in fact the non-analyticity of the
one-loop self-energy disappears when it is calculated with improved vertices
and/or improved propagators that incorporate the imaginary part of the
self-energy.


title: Constructing CP-Odd Observables

abstract:
  In these lectures we review the general features necessary to construct $\cp$
odd observables and study illustrative examples. We present in some detail the
case of $\cp$ violation in hyperon decays. We survey different observables
sensitive to $\cp$ violating new physics, concentrating on the search for
electric-dipole moments in high energy experiments.


title: CP Violation in Hyperon Decays

abstract:
  In this talk we review the status of the theoretical estimates for CP
violating asymmetries in non-leptonic hyperon decays.


title: Inflation from superstrings

abstract:
  We investigate the possibility of obtaining inflationary solutions of the
slow roll type from a low energy Lagrangian coming from superstrings. The
advantage of such an approach is that in these theories the scalar potential
has only one free parameter (the Planck scale) and therefore no unnatural fine
tuning may be accommodated. We find that in any viable scheme the dilaton and
the moduli fields have to be stabilized and that before this happens, no other
field may be used as the inflaton. Then inflation may occur due to chiral
matter fields. Demanding that the potential terms associated with the chiral
fields do not spoil the dilaton and moduli minimization leads to severe
constraints on the magnitude of the density fluctuations.


title:
On pi-pi Correlations in Polarized Quark Fragmentation Using the Linear
  Sigma Model

abstract:
  Using the linear sigma model to describe quark--pion interactions, we compute
polarization asymmetries in quark fragmentation. We show that the effects of
transverse quark polarizations appear in the correlation between the two
leading pions in a jet produced by the fragmentation of a quark. Such
asymmetries provide a window to the nature of chiral symmetry breaking in QCD.


title:
A Model of Low-lying States in Strongly Interacting Electroweak
  Symmetry-Breaking Sector

abstract:
  It is proposed that, in a strongly-interacting electroweak sector, besides
the Goldstone bosons, the coexistence of a scalar state ($H$) and vector
resonances such as $A_1$ [$I^G(J^P)=1^-(1^+$)], $V$ [$1^+(1^-)$] and
$\omega_H^{}$ [$0^-(1^-)$] is required by the proper Regge behavior of the
forward scattering amplitudes. This is a consequence of the following
well-motivated assumptions: (a). Adler-Weisberger-type sum rules and the
superconvergence relations for scattering amplitudes hold in this strongly
interacting sector; (b). the sum rules at $t=0$ are saturated by a minimal set
of low-lying states with appropriate quantum numbers. It therefore suggests
that a complete description should include all these resonances. These states
may lead to distinctive experimental signatures at future colliders.


title:
ZFITTER -- An Analytical Program for Fermion Pair Production in e+e-
  Annihilation

abstract:
  We describe how to use ZFITTER, a program based on a semi-analytical approach
to fermion pair production in e+e- annihilation and Bhabha scattering. A
flexible treatment of complete ${\cal O}(\alpha)$ QED corrections, also
including higher orders, allows for three calculational {\bf chains} with
different realistic sets of restrictions in the photon phase space. {\tt
ZFITTER} consists of several {\bf branches} with varying assumptions on the
underlying hard scattering process. One includes complete ${\cal O}(\alpha)$
weak loop corrections with a resummation of leading higher-order terms.
Alternatively, an ansatz inspired from S-matrix theory, or several
model-independent effective Born cross sections may be convoluted. The program
calculates cross sections, forward-backward asymmetries, and for $\tau$~pair
production also the final-state polarization. Various {\bf interfaces} allow
fits to be performed with different sets of free parameters.


title:
High-colour pomerons with a running coupling constant in the
  Hartree-Fock approximation

abstract:
  The Hartree-Fock approximation is applied to study the "high-colour pomerons"
in the system of many reggeized gluons with a running QCD coupling constant. It
is shown that, contrary to the fixed coupling case, the high-colour pomerons
result supercritical, although with a smaller intercept than the multipomeron
states.


title: CP Violation in $\tau\rightarrow 3\pi\nu_\tau$

abstract:
  We consider CP violating effects in the decays $\tau\rightarrow
(3\pi)\nu_\tau$ where both the ${\rm J}^{\rm P}=1^+$ resonance, $a_1$, and
${\rm J}^{\rm P}=0^-$ resonance, $\pi^\prime$, can contribute. The interference
between the $a_1$ and $\pi^\prime$ resonances can lead to enhanced CP-violating
asymmetries whose magnitudes depend crucially on the $\pi^\prime$ decay
constant, $f_{\pi^\prime}$. We make an estimate of $f_{\pi^\prime}$ with a
simplified chiral Lagrangian coupled to a massive pseudoscalar field, and we
compare the estimates from the non-relativistic quark model and from the QCD
sum rule with the estimate from the `mock' meson model. We then estimate
quantitatively the size of CP-violating effects in a multi-Higgs-doublet model
and scalar-leptoquark models. We find that, while CP-violating effects in the
scalar-leptoquark models may require more than $10^{10}$ $\tau$ leptons,
CP-violating effects from the multi-Higgs-doublet model can be seen at the
$2\sigma$ level with about $10^7$ $\tau$ leptons using the chiral Lagrangian
estimate of $f_{\pi^\prime}=(1\sim 5)\times 10^{-3}$ GeV.


title: Low-Temperature QED with External Magnetic Field

abstract:
  Low-temperature expansion of the effective Lagrangian of the QED$_{3+1}$ with
a uniform magnetic field and a finite chemical potential is performed.
Temperature corrections, as well as zero-temperature expression for the
effective Lagrangian are presented as finite sums over partially filled Landau
levels.


title:
Mass corrections in $J/\psi \to B\bar B$ decay and the role of
  distribution amplitudes

abstract:
  We consider mass correction effects on the polar angular distribution of a
baryon--antibaryon pair created in the chain decay process $e^-e^+ \to J/\psi
\to B\bar B$, generalizing a previous analysis of Carimalo. We show the
relevance of the features of the baryon distribution amplitudes and estimate
the electromagnetic corrections to the QCD results.


title: Nonoblique Corrections in Technicolor Theories Revisited

abstract:
  In extended technicolor (ETC) theories, while the sideways ETC boson exchange
decreases the width $\Gamma_b \equiv \Gamma (Z\rightarrow b \bar{b})$, the
flavor-diagonal ETC boson exchange tends to increase it, and the ETC-corrected
$R_b \equiv \Gamma_b / \Gamma_{\mbox{\footnotesize had}}$ value could agree
with recent measurements. The $\tau$ asymmetry parameter may also increase in a
way consistent with experiment. The weak-interaction $\rho$ parameter receives
a correction from diagonal ETC exchange which is just barely acceptable by
experiments.


title:
Isospin Violation in Chiral Perturbation Theory and the Decays $\eta \ra
  \pi \ell \nu$ and $\tau \ra \eta \pi \nu$

abstract:
  I discuss isospin breaking effects within the standard model. Chiral
perturbation theory presents the appropriate theoretical framework for such an
investigation in the low--energy range. Recent results on the electromagnetic
contributions to the masses of the pseudoscalar mesons and the $K_{\ell 3}$
amplitudes are reported. Using the one--loop formulae for the $\eta_{\ell 3}$
form factors, rather precise predictions for the decay rates of $\eta
\rightarrow \pi \ell \nu$ can be obtained. Finally, I present an estimate of
the $\tau \ra \eta \pi \nu$ branching ratio derived from the dominant meson
resonance contributions to this decay.


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 $\lambda_{ijk}\;\ov{D}_i\, \ov{D}_j\, \ov{U}_k$ 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
$\lambda_{dsu}$ coupling; they do provide a bound on the $\lambda_{dbu}$
coupling, which we calculate. We find that the best bound on $\lambda_{dsu}$
arises from double nucleon decay into two kaons; the calculation is discussed
in detail. 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:
Contributions of below--threshold decays to ${\cal {MSSM}}$ Higgs
  branching ratios

abstract:
  We calculate all the experimentally relevant branching ratios of the Higgs
bosons of the Minimal Supersymmetric Standard Model, paying particular
attention to the contributions from below--threshold decays. We show that in
some cases these can significantly change the pattern of branching ratios
calculated without taking off--shell effects into account


title: Sphalerons and Conformally Compactified Minkowski Spacetime

abstract:
  Solutions to the Yang-Mills field equations which describe exploding or
imploding shells of gauge field and which may serve as approximations to the
exploding sphaleron are discussed. The solutions are conformally related to
$SO(2)\times SO(4)$ invariant Yang-Mills solutions. The behavior of fermions in
the gauge field background and higher gauge groups are also considered.


title: Bound States in Galilean-Invariant Quantum Field Theory

abstract:
  We consider the nonrelativistic quantum mechanics of a model of two spinless
fermions interacting via a two-body potential. We introduce quantum fields
associated with the two particles as well as the expansion of these fields in
asymptotic ``in'' and ``out'' fields, including such fields for bound states,
in principle. We limit our explicit discussion to a two-body bound state. In
this context we discuss the implications of the Galilean invariance of the
model and, in particular, show how to include bound states in a strictly
Galilean-invariant quantum field theory.


title: The Decay b-s+gamma in SUSY Extensions of the Standard Model

abstract:
  A brief review is given of the decay b-s+gamma in SUSY extensions of the
Standard Model.It is found that the recent CLEO results put strong constraints
on the parameter space of the minimal N=1 Supergravity unified theory.Dark
matter analyses are also strongly constrained for mu>0.


title:
Model-Independent Comparison of Direct vs. Indirect Detection of
  Supersymmetric Dark Matter

abstract:
  We compare the rate for elastic scattering of neutralinos from various nuclei
with the flux of upward muons induced by energetic neutrinos from neutralino
annihilation in the Sun and Earth. We consider both scalar and axial-vector
interactions of neutralinos with nuclei. We find that the event rate in a kg of
germanium is roughly equivalent to that in a $10^5$- to $10^7$-m$^2$ muon
detector for a neutralino with primarily scalar coupling to nuclei. For an
axially coupled neutralino, the event rate in a 50-gram hydrogen detector is
roughly the same as that in a 10- to 500-m$^2$ muon detector. Expected
experimental backgrounds favor forthcoming elastic-scattering detectors for
scalar couplings while the neutrino detectors have the advantage for
axial-vector couplings.


title:
Strategies for Probing CP Properties in the Top Quark System at $e^-e^+$
  and Hadron Colliders

abstract:
  I discuss strategies for probing CP properties in the top quark system at
$e^-e^+$ and hadron Colliders. The magnitudes of CP violation effects predicted
by various models are reviewed. I also discuss the potential of various current
and future colliders in measuring the CP asymmetry associated with the
productions and/or decays of the top quarks.


title:
$e^+ e^- \to e^- {\bar \nu_e} u {\bar d}$ from LEP to linear collider
  energies

abstract:
  The complete tree level cross section for the process $e^+e^- \to e^-
\bar\nu_e u \bar{d}$ is computed using the GRACE system, a program package for
automatic amplitude calculation. Special attention is brought to the gauge
violation problem induced by the finite width of the $W$-boson. The {\it
preserved gauge scheme} is introduced and an event generator which includes
double-resonant, single-resonant and non-resonant diagrams with no need for a
cut on the electron polar angle is presented. Since no cut needs to be applied
to the electron, the generator can be used to estimate background for searches
involving jets and missing energy. A monojet event rate estimation based on
this process at LEP-I energy is discussed.


title:
High Harmonic Configurations of Cosmic Strings: An Analysis of
  Self-Intersections

abstract:
  A general formulation for describing odd-harmonic cosmic strings is developed
and used to determine the self-intersection properties of high-harmonic loops.
This is important because loop formation mechanisms produce high-harmonic
components (kinks) which can only be eliminated very slowly by gravitational
radiation, damping by the dense surrounding plasma in the era of string
formation, or by the expansion of the Universe. For the class of loops examined
it has been found that in the high-harmonic limit, essentially all cosmic loops
self-intersect.


title:
A Re-examination of the Path Ordered Approach to Real Time Thermal Field
  Theory

abstract:
  We argue that the asymptotic condition should not be applied in the
derivation of the real time formalism of thermal field theory. It is shown
that, contrary to popular belief, the generating functional of time ordered
Green functions does not factorise. When no asymptotic condition is applied to
the real time formalism, we find that the normal two component Feynman rules
arises naturally. In addition, the extra Feynman rule that is applied when
calculating vacuum diagrams is simply derived. We also clear up any doubts
regarding the equivalence of the real and imaginary time formalisms. Finally,
we consider these results in the case of the new real time contour.


title: Supersymmetric Left-Right Model and its Phenomenological Implications

abstract:
  We review here our study of a supersymmetric left-right model (SLRM). In the
model the $R$-parity is spontaneously broken. Phenomenologically novel feature
of the model is the occurrance of the doubly charged particles in the Higgs
sector, which are possibly light enough to be seen in the next linear collider.
Detection of the doubly charged higgsinos in the next linear collider is
discussed.


title: Off-Shell Axial Anomaly via the \gamma^* \pi^0 -> \gamma Transition

abstract:
  The $\gamma^* \pi^0 \rightarrow \gamma$ form factor, including the extension
off the pion mass-shell, is obtained from a generalized impulse approximation
within a QCD-based model field theory known to provide an excellent description
of the pion charge form factor. This approach implements dressing of the vertex
functions and propagators consistent with dynamical chiral symmetry breaking,
gauge invariance, quark confinement and perturbative QCD. Soft nonperturbative
behavior, dictated by the axial anomaly, is found to evolve to the perturbative
QCD limit only for \mbox{$Q^2 \geq 20~{\rm GeV}^2$}.


title: The Isospin Splittings of Heavy-Light Quark Systems

abstract:
  The isospin mass splittings of the pseudoscalar and vector D and B
light-heavy quark system have been calculated using the method of QCD sum
rules. Nonperturbative QCD effects are shown to be very small, so that mass
splittings arise almost completely from current quark mass splitting and
electromagnetic effects, for which a new gauge invariant QED treatment is used.
The results are consistent with experiment. A measurement of the isospin
splitting of the vector B mesons would give valuable information about quark
mass splittings.


title: The Impact of QCD and Light-Cone Quantum Mechanics on Nuclear Physics

abstract:
  We discuss a number of novel applications of Quantum Chromodynamics to
nuclear structure and dynamics, such as the reduced amplitude formalism for
exclusive nuclear amplitudes. We particularly emphasize the importance of
light-cone Hamiltonian and Fock State methods as a tool for describing the
wavefunctions of composite relativistic many-body systems and their
interactions. We also show that the use of covariant kinematics leads to
nontrivial corrections to the standard formulae for the axial, magnetic, and
quadrupole moments of nucleons and nuclei.


title:
Long Distance Contributions to Penguin Processes $b\rightarrow s\gamma$
  and $b\rightarrow d \gamma$

abstract:
  We consider the long distance contributions to inclusive penguin processes
through processes like $b\rightarrow s V$ and $b\rightarrow d V$ where $V$ are
$^3S_1(c\bar c)$ states $\psi_i$ in the former case and include $\rho$,
$\omega$ for the latter case. We carefully examine vector dominance for $\bar c
c$ states, and conclude that there is a large suppression of $\psi\sim \gamma$
transition when $\psi$ is at $q^2 = 0$. The long distance effects can be at
most 10\% in both the amplitudes for $b\rightarrow s\gamma$ and $b\rightarrow d
\gamma$. Although the long distance contributions are small, the ratio
$BR(b\rightarrow d\gamma)/BR(b \rightarrow s \gamma) = |V_{td}/V_{ts}|^2$ does
not hold due to significant $u$ and $c$ loop contributions to the short
distance $b\rightarrow d\gamma$ amplitudes .


title: Spontaneous Family Symmetry Breaking And Fermion Mixing

abstract:
  We propose a theory to describe fermion mixing. The theory respects the
maximal abelian family symmetries which are spontaneously broken down at a
large scale. We find that quark mixing can be well described in this theory.
Some concrete models are constructed. The crucial point for model building is
to introduce some new particles which are SU(2) gauge singlets and carry -1/3
electric charge. The approximate family symmetries in our low energy effective
theory are naturally achieved. Some interesting phenomena in the effective
theory, especially with two Higgs-doublets, are discussed.


title:
On the possibilities to study the exotic state $1^{-+}$ in the
  experiments on photoproduction of the $\pi\eta$, $\pi\eta'$ systems

abstract:
  We show that in photoproduction experiments there are propitious conditions
to study the exotic state $1^{-+}$ in the $\pi\eta$ and $\pi\eta'$ channels. We
show that for unpolarized photon beam the contributions with natural and
unnatural parity exchanges do not interfere with each other, the fact which
gives additional arguments in the estimation of the correctness of phase shift
analysis. In the reaction of photoproduction of $\pi^+\eta$ system in the mass
range of $a_2(1320)$ more strong limit on the upper bound of the product
$\Gamma(1^{-+}\rightarrow \pi\gamma)\times{\rm Br}(1^{-+}\rightarrow\pi\eta)$
can be obtained than in experiments on Primakoff production on nuclei. In the
photoproduction of $\pi^0\eta$ and $\pi^0\eta'$ systems there are propitious
conditions to study the state $1^{-+}$ in the coherent photoproduction on
nuclei, the fact which will allow to enlarge significantly the statistics and
makes the phase shift analysis more simple.