title: Atomic effects in tritium beta decay

abstract:
  The electron neutrino mass has been measured in several tritium beta decay
experiments. These experiments are sensitive to a small neutrino mass because
the energy release of the decay is small. But the very smallness of the energy
release implies that the Coulomb interactions of the slowly moving emitted beta
electron are relatively large. Using field theoretic techniques, we derive a
systematic and controlled expansion which accounts for the Coulomb effects,
including the mutual interaction of the beta ray electron and the electron in
the final $^3{\rm He}^+$ ion. In our formulation, an effective potential which
describes the long range Coulomb force experienced by the beta ray is
introduced to ensure that our expansion is free of infrared divergences. Both
the exclusive differential decay rate to a specific final $^3{\rm He}^+$ state
and the inclusive differential decay rate are calculated to order $\eta^2$,
where $\eta$ is the usual Coulomb parameter. We analyze the order $\eta^2$
correction to the beta ray spectrum and estimate how it may affect the neutrino
mass squared parameter and the endpoint energy when this corrected spectrum is
used to compare with the experiments. We find that the effect is small.


title: Resurrection of the Sigma Meson

abstract:
  It is shown from a very general model and an analysis of data on the lightest
0++ meson nonet that the f0(980) and f0(1200) resonance poles are two
manifestations of the same ss state. Similarily the a0(980) and the a0(1450)
are likely to be two manifestations of the same qq state. On the other hand,
the uu+dd state, when unitarized and strongly distorted by hadronic mass
shifts, becomes an extremely broad Breit-Wigner-like background, m=860 MeV,
Gamma=880 MeV, with its pole at s=(0.158-i0.235) GeV^2. This we identify with
the sigma meson required by models for spontaneous breaking of chiral symmetry.


title:
QCD-Motivated Pomeron and High Energy Hadronic Diffractive Cross
  Sections

abstract:
  Soft diffractive cross sections in $pp$ (or $\bar pp$), $\pi p$ and $\gamma
p$ collisions are calculated using QCD-motivated pomeron. The $s$-channel
unitarization of the amplitude is performed by the eikonal approach, and in the
framework of the quark structure of hadrons the colour screening is taken into
account. The performed description of the diffractive processes has led to the
parameters of the bare pomeron $P$ which occurred to be close to the
corresponding parameters of the Lipatov's pomeron. Parameters of the bare
pomeron and those of the three-reggeon block $PGG$ ($G$ is a reggeized gluon)
has been fixed by the data at moderately high energies; for superhigh energies
the predictions are made. The intercept of the bare pomeron is found to be in
remarkable agreement with the low-$x$ data for deep inelastic scattering. An
evaluation of the effective colour transparency radius is done which can be
used in hadron-nuclei reactions.


title:
Momentum Dependent Photon-Vector Meson Coupling and Parity Violating
  effects in B --> X_s l^+ l^-

abstract:
  We examine the leptonic forward-backward and polarization (left-right)
asymmetries in the dileptonic B -> X_s l^+ l^- decay when the momentum
dependence of $\psi$ and $\psi'-\gamma$ conversion strength is taken into
account. The results indicate only a small shift in the asymmetry
distributions.


title: Destabilizing Divergences in Supergravity Theories

abstract:
  We study the stability of the gauge hierarchy in hidden-sector supergravity
theories. We show that a destabilizing tadpole can appear if a theory has a
gauge- and global-symmetry singlet with renormalizable couplings to the visible
fields. We also find a quadratically divergent two-loop contribution to the
supersymmetric effective potential. This term illustrates the difficulty of
using the "LHC mechanism" to control quadratic divergences in theories with
Planck-scale vevs.


title:
Hadronization in Nuclear Environment and Electroproduction of Leading
  Hadrons

abstract:
  Radiative energy loss of a highly virtual quark originating from a
deep-inelastic electron scattering plays a crucial role in production of
leading hadrons off nuclei. The density of energy loss for gluon radiation
turns out to be time- and energy--dependent in inclusive hadron production.
Important phenomena involved are Sudakov's suppression of no radiation of that
part of gluon spectrum, which is forbidden by energy conservation, and color
transparency, which suppresses the final state interaction of the produced
colorless wave packet. We model the soft part of hadronization, which usually
is supposed to be due to the color strings, using also the gluon radiation and
nicely reproduce the string parameters. Our parameter-free calculations provide
a good agreement with available data on $z_h$-dependence of the quark
fragmentation function in vacuum, as well as $\nu$-, $z_h$- and
$Q^2$-dependence of nuclear effects. We come to the conclusion that the energy
range of ELFE - HERMES is most sensitive to the underlying dynamics of
hadronization provided that nuclear targets are used.


title:
The Role of the Coherence Length in Exclusive Electroproduction of
  Vector Mesons off Nuclei

abstract:
  The variation of the coherence length $l_c=2\nu/(Q^2+m_V^2)$ in virtual
photoproduction of vector mesons off nuclei as a function of the photon energy
$\nu$ or virtuality $Q^2$ results in dramatic changes in the values of the
nuclear transparency. Color transparency effects can be easily mixed up with
the effects of the coherence length in incoherent photoproduction on nuclei.


title: Perturbed Electroweak Strings and Fermion Zero Modes

abstract:
  The effect of perturbations of electroweak strings on quark zero modes is
studied in 2+1 and 3+1 dimensions. As first discovered by Naculich, it is found
that the bosonic perturbations that destabilize the string give a mass to the
zero modes and also lift their degeneracy. The effect of the zero modes on the
stability of the string is discussed qualitatively and we argue that the
fermionic vacuum instability found by Naculich should lead to a distortion of
the bosonic string but not be responsible for decay.


title:
QCD Corrections to Spin Dependent Drell-Yan and a Global Subtraction
  Scheme

abstract:
  We present QCD corrections to the Drell-Yan process in the transversely
polarized, longitudinally polarized and unpolarized cases. The analytical
results are presented in a form valid for all $n$-dimensional regularization
schemes. A universal mass factorization scheme is presented in which the
results reduce to those of dimensional reduction. The connection between the
parton distributions and fragmentation functions of dimensional reduction and
those of dimensional regularization is elucidated in a simple manner. Numerical
results are presented for proton-proton collisions at energies relevant to RHIC
(Relativistic Heavy Ion Collider). The perturbative stability of the transverse
and longitudinal asymmetries is investigated.


title: New Issues In Low Energy Dynamical Supersymmetry Breaking

abstract:
  Comparatively simple models, with low energy structure similar to that of the
MSSM, but with far fewer arbitrary parameters, can be constructed in which
supersymmetry is dynamically broken at low energies. The phenomenology of these
models is somewhat different than that of the usual scenario with supersymmetry
broken in a hidden sector.


title:
Collision Induced Decays of Electroweak Solitons: Fermion Number
  Violation with Two and Few Initial Particles

abstract:
  We consider a variant of the standard electroweak theory in which the Higgs
sector has been modified so that there is a classically stable weak scale
soliton. We explore fermion number violating processes which involve soliton
decay. A soliton can decay by tunnelling under the sphaleron barrier, or the
decay can be collision induced if the energy is sufficient for the barrier to
be traversed. We present a classical solution to the Minkowski space equations
of motion in which a soliton is kicked over the barrier by an incoming pulse.
This pulse corresponds to a quantum coherent state with mean number of $W$
quanta $\sim 2.5/g^2$ where $g$ is the $SU(2)$ gauge coupling constant. We also
give a self-contained treatment of the relationship between classical
solutions, including those in which solitons are destroyed, and tree-level
quantum amplitudes. Furthermore, we consider a limit in which we can reliably
estimate the amplitude for soliton decay induced by collision with a single
$W$-boson. This amplitude depends on $g$ like $\exp (-cg^{-1/3})$, and is
larger than that for spontaneous decay via tunnelling in the same limit.
Finally we show that in soliton decays, light $SU(2)_L$ doublet fermions are
anomalously produced. Thus we have a calculation of a two body process with
energy above the sphaleron barrier in which fermion number is violated.


title:
Mass or Gravitationally Induced Neutrino Oscillations? -- A Comparison
  of $\B$ Neutrino Flux Spectra in a Three--Generation Framework

abstract:
  Both gravitational and mass induced neutrino oscillation mechanisms provide
possible resolutions to the Solar Neutrino Problem. The distinguishing feature
between the two mechanisms is their dependence on the neutrino energy. We
investigate the implications of this by computing the $\B$ neutrino spectrum as
determined from each mechanism using a realistic three--flavor evolution model.
We find that in the limit of small $\tetau$ mixing angle, the differences are
significant enough to observe in future solar neutrino experiments.


title: Asymmetric Inflationary Reheating and the Nature of Mirror Universe

abstract:
  The existence of a shadow world (or mirror universe) with matter and forces
identical to that of the visible world but interacting with the latter only via
gravity can be motivated by superstring theories as well as by recent attempts
to understand the nature of a sterile neutrino needed if all known neutrino
data are to be consistent with each other. A simple way to reconcile the
constraints of big bang nucleosynthesis in such a theory is to postulate that
the reheating temperature after inflation in the mirror universe is lower than
that in the visible one. We have constructed explicit models that realize this
proposal and have shown that the asymmetric reheating can be related to a
difference of the electroweak symmetry breaking scales in the two sectors,
which is needed for a solution of the neutrino puzzles in this picture.
Cosmological implications of the mirror matter are also discussed.


title:
Chiral Symmetry Restoration at Finite Temperature in the Dual
  Ginzburg-Landau Theory

abstract:
  We study the relation between QCD-monopole condensation and dynamical
chiral-symmetry breaking in the dual Ginzburg-Landau Theory, which realizes the
color confinement due to the dual Meissner effect. Solving the Schwinger-Dyson
equation at finite temperature numerically, we find the chiral symmetry is
restored at high temperature. The critical temperature of the chiral symmetry
restoration is strongly correlated with the string tension.


title: Atmospheric Neutrinos

abstract:
  The atmospheric neutrino-flux is calculated over the wide energy range from 1
GeV to 3,000 GeV for the study of neutrino-physics using the data from
underground neutrino-detectors. The uncertainty of atmospheric neutrino-flux is
also discussed. A brief comment is made to interpret the anomaly in terms of
neutrino oscillations.


title: Structure of Electroweak Radiative Corrections

abstract:
  Looking into the inside of radiative corrections is an interesting subject as
a deeper study of the standard electroweak theory after its remarkable success
in the precision analyses. I will discuss here a test of ``structure" of the EW
radiative corrections to the weak-boson masses, and show that we can now
analyze several different parts separately.


title: How About Vortons ?

abstract:
  It has been suggested that cosmological dark matter may include a population
of vortons (meaning small centrifugally stabilised cosmic string loops) as an
outcome of (non-standard) electroweak symmetry breaking. The implications for
this conjecture of recent theoretical progress on superconducting string theory
are discussed, particularly in relation to problems of stability. It is
tentatively concluded that if the underlying field theory provides a carrier
field with mass not too far below that of the relevant Higgs mass (which may be
a few hundred G.e.V.) electroweak string formation may conceivably produce
enough vortons (with an extended mass distribution peaking perhaps at several
hundred T.e.V.) to provide a marginally significant dark matter contribution.


title: Clan Structure in Rapidity Intervals

abstract:
  We present a cascading model for a single jet, inspired to QCD and to the
phenomenological analysis of multiplicity distributions. The model, describing
as it does a two dimensional evolution in virtuality and rapidity, allows
analytical predictions for clan analysis parameters to be made.


title: On the observability of Majoron emitting double beta decays

abstract:
  Because of the fine--tuning problem in classical Majoron models in recent
years several new models were invented. It is pointed out that double beta
decays with Majoron emission depend on new matrix elements, which have not been
considered in the literature. A calculation of these matrix elements and phase
space integrals is presented. We find that for new Majoron models extremely
small decay rates are expected.


title: Diffractive $J/\psi$ photoproduction as a probe of the gluon density

abstract:
  We use perturbative QCD, beyond the leading $\ln Q^2$ approximation, to show
how measurements of diffractive $J/\psi$ production at HERA can provide a
sensitive probe of the gluon density of the proton at small values of Bjorken
$x$. We estimate both the effect of the relativistic motion of the $c$ and
$\overline{c}$ within the $J/\psi$ and of the rescattering of the
$c\overline{c}$ quark pair on the proton. We find that the available data for
diffractive $J/\psi$ photoproduction can discriminate between the gluon
distributions of the most recent sets of partons.


title: $t$-Channel Unitarity Construction of Small-x Kernels

abstract:
  We present the BFKL equation as a reggeon Bethe-Salpeter equation and discuss
the use of reggeon diagrams to obtain 2-2 and 2-4 reggeon interactions at
$O(g^4)$. We then outline the dispersion theory basis of multiparticle
$j$-plane analysis and describe how a gauge theory can be studied by combining
Ward identity constraints with the group structure of reggeon interactions. The
derivation of gluon reggeization, the $O(g^2)$ BFKL kernel, and $O(g^4)$
corrections, is described within this formalism. We give an explicit expression
for the $O(g^4)$ forward ``parton'' kernel in terms of logarithms and evaluate
the eigenvalues. A separately infra-red finite component with a holomorphically
factorizable spectrum is shown to be present and conjectured to be a new
leading-order partial-wave amplitude. A comparison is made with Kirschner's
discussion of $O(g^4)$ contributions from the multi-Regge effective action.


title: Textures, Family Symmetries and Neutrino Masses

abstract:
  We review recent work on the interplay between broken family symmetries which
give rise to approximate texture zeros in the mass matrices of the quarks and
leptons and the presence of certain hierarchy patterns in the spectrum of
massive neutrinos.


title: Computing numerically the functional derivative of an effective action

abstract:
  The functional derivative of the effective action with respect to an external
field is part of the equation of motion of this field if one-loop effects
induced by quantum fluctuations or thermal fluctuations are included when
minimizing the action of this field. Examples occur in all field theories
displaying classical solutions or - as in the Nambu-Jona-Lasinio model - self
consistent field configurations. We describe here a numerical method for
computing such functional derivatives; we use a fermion field with Yukawa
interaction to an external field as an example which is sufficiently simple and
sufficiently general. We compare the computed functional derivative to
analytical estimates.


title: Charmed Strange Pentaquarks in the Large $N_c$ Limit

abstract:
  The properties of pentaquarks containing a heavy anti-quark and strange
quarks are studied in the bound state picture. In the flavor SU(3) limit, there
are many pentaquark states with the same binding energy. When the SU(3)
symmetry breaking effects are included, however, three states become
particularly stable due to a ``Gell-Mann--Okubo mechanism''. They are the $\bar
Qsuud$ and $\bar Qsudd$ states discussed by Lipkin, and a a previously
unstudied $\bar Qssud$ state. These states will have $J^P={1\over2}^+$ and
their masses are estimated. These states, if exist, may be seen in experiments
in the near future.


title: Semileptonic B and Lambda_b Decays and Local Duality in QCD

abstract:
  The inclusive and exclusive semileptonic decay distributions for b -> c decay
are computed in the Shifman-Voloshin limit. The inclusive decay distributions
(computed using an operator product expansion) depend on quark masses, and the
exclusive decay distributions depend on hadron masses. Nevertheless, we show
explicitly how the first two terms in the 1/m expansion match between the
inclusive and exclusive decays. Agreement between the inclusive and exclusive
decay rates requires a minimum smearing region of size Lambda_QCD before local
duality holds in QCD. The alpha_s corrections to the inclusive and exclusive
decay rates are also shown to agree to order (log m)/m^2. The alpha_s/m^2
corrections are used to obtain the alpha_s correction to Bjorken's inequality
on the slope of the Isgur-Wise function.


title: Neutralino Contribution to the Mass Difference of $B_d^0-\bar B_d^0$

abstract:
  We present a detailed and complete calculation of the neutralino contribution
to the mass difference $\Delta m_{B_d^0}/m_{B_d^0}$\ within the MSSM. We
include the complete mixing matrices of the neutralinos and of the scalar
partners of the left and right handed bottom quark. We find that the neutralino
contribution is generally small but can be of the same order of the chargino
contribution and much larger than that of the gluino over a small range of
$m_S$, given $m_{g_2}$ and $\mu$ and for $\tan\beta\sim 50$.


title: A thermodynamical model of hadron production in $e^+e^-$ collisions

abstract:
  The hadron production in $e^+e^-$ collisions is studied assuming that
particles originate in a hadron gas at thermal and chemical equilibrium. The
parameters of the hadron gas are determined with a fit to the average
multiplicities of various hadron species measured at LEP and PEP-PETRA
colliders. An impressive agreement is found between the predictions of this
model and data for almost all particles over a range of production rate of four
orders of magnitude. The temperature values found at the centre of mass
energies of LEP and PEP-PETRA are around $165$ MeV.


title: Non-Perturbative Aspects of Multiparticle Production

abstract:
  Processes with multiparticle final states in weakly coupled theories, both
with and without instantons, cannot be studied perturbatively at most
interesting energies and multiplicities. Semiclassical approaches to the
calculation of their cross sections are reviewed.


title:
Light Colour-Triplet Higgs is Compatible with Proton Stability: An
  alternative approach to the doublet-triplet splitting problem

abstract:
  It is usually assumed that the proton stability requires the coloured triplet
partner of the electroweak Higgs doublet to be superheavy (with a mass $\sim
M_{GUT}$). We show that this is a very model-dependent statement and the colour
triplet can be as light as the weak doublet without leading to the proton decay
problem: instead of using the mass difference the splitting can occur between
the doublet and triplet Yukawa coupling constants. In this scenario the GUT
symmetry breaking automatically induces an extremely strong suppression $\sim
M_W/M_{GUT}$ of the coloured Higgs effective Yukawa coupling; this happens
without any fine--tuning, just because of the Clebsch factors. Conceptual
differences of the above picture are: (1) an essentially stable proton: both $d
= 5$ and $d = 6$ proton decay mediating operators are suppressed by the same
factors $\sim (M_w/M_{GUT})^2$; (2) the possibility of solving the $\mu$
problem by the light gauge singlet field (this fact would lead to the
destabilization of the hierarchy in the standard case); (3) the existence of
the long--lived, light, coloured and charged supermultiplet in the 100 GeV mass
region. We construct two explicit SO(10) examples with the above properties,
with superpotentials most general under the symmetries.


title: Almost-Goldstone Bosons from Extra-Dimensional Gauge Theories

abstract:
  A mechanism is presented through which very light scalar degrees of freedom
obeying the nonlinear sigma model equation can emerge in spontaneously broken
gauge theories.
  The mechanism operates in extra dimensional theories in which a) there are
massless gauge fields present in the theory prior to compactification, and b)
the extra dimensions are inhomogeneous in such a way that symmetry breaking
Higgs fields aquire vevs only at very localised points on the manifold. These
conditions are naturally fulfilled in orbifold compactifications of string
theory. Possible applications include cosmic texture, axions and family
symmetry.


title: Neutrinos and Structure of the Intermediate Mass Scale

abstract:
  Neutrino data lead via the see-saw mechanism to masses of the right handed
neutrinos at the intermediate mass scale. Simple formalism is suggested which
incorporates the quark - lepton symmetry and allows one to find properties of
the intermediate scale (masses and mixing) from neutrino data. Averaged mass
scale and the mass hierarchy parameter are introduced and fixed by the data.
They determine natural ranges of masses and mixing at the intermediate scale.
In particular, scenario which includes the MSW solution of the solar neutrino
problem and tau neutrino as the hot component of Dark Matter of the Universe
leads to $M_2 = (2 - 4) \cdot 10^{10}$ GeV and $M_3 = (4 - 8) \cdot 10^{12}$
GeV in agreement with the linear mass hierarchy. Strong deviations from the
natural ranges imply fine tuning of parameters or/and certain symmetry of the
Majorana mass matrix of the right handed neutrinos.


title:
$Z_2$ as the Topological Origin of B+L Violation in the Hot Electroweak
  Theory

abstract:
  The space of static finite-energy configurations in the electroweak theory
admits a $Z_2$ topological structure. More precisely, we show that this space
contains two disconnected sectors of unstable gauge-Higgs fields odd under a
properly defined generalized parity. This classification extends the
description of baryon and lepton number violating electroweak processes to the
symmetric phase of the theory. Configurations with odd pure-gauge behaviour at
spatial infinity, such as the sphaleron, multisphalerons, electroweak strings
as well as an infinite surface of their equivalents, have half-integer
Chern-Simons number and mediate B+L violating processes in the early universe.
Finite-energy configurations with even pure-gauge behaviour, such as the $S^*$
new sphaleron and electroweak strings, are topologically equivalent to the
vacuum and are irrelevant for B+L violation. We discuss the possible formation
of B+L violating quark-lepton condensates in the symmetric high-temperature
phase of the electroweak theory.


title:
Excited Charmed Baryon Decays and Their Implications for Fragmentation
  Parameters

abstract:
  The production of the excited charmed baryon doublet $\Lambda_c^*$ via
fragmentation is studied. An analysis of the subsequent hadronic decays of the
doublet within the framework of heavy hadron chiral perturbation theory
produces expressions for both the angular distribution of the decay products
and the polarization of the final state heavy baryon in terms of various
nonperturbative fragmentation parameters. Future experimental investigation of
this system will determine these parameters. In addition, recent experimental
results are shown to fix one of the parameters in the heavy hadron chiral
Lagrangian.


title: Theoretical Aspects of CP Violation in Hyperon Decays

abstract:
  I review the estimate of the CP violating asymmetry $A(\Lambda^0_-)$ within
the standard model. I then review the estimate of the upper bound on this
asymmetry that arises from measurements of CP violation in kaon decays.


title: Confinement and renormalization

abstract:
  The haaron gas description is reviewed for the QCD vacuum. The role of
non-renormalizable operators is emphasised in the mechanism which generates the
string tension. Additional examples are mentioned where certain
non-renormalizable operators of the bare lagrangian turn out to be important at
finite energy scale.


title: A note on the GG-->PI 0 PI 0 reaction in the 1/N expansion of ChPT

abstract:
  In this work we present the results of a complete calculation of the $\gamma
  \gamma\rightarrow \pi^0\pi^0$ amplitude to leading order in the large $N$
approximation ($N$ being the number of Goldstone bosons) up to order
$m^2_{\pi}/F^2$. The amplitude turns to be proportional to that of
$\pi^+\pi^-\rightarrow \pi^0\pi^0$. In spite of the fact that this
factorization property cannot hold in general (as it was recently pointed out
by Morgan and Penington), it appears here since in the large $N$ limit only the
$I=J=0$ channel contributes to the $\gamma \gamma\rightarrow \pi^0\pi^0$
reaction. Moreover it seems to be a reasonable approximation in
  this case since it is possible to reproduce, as a prediction, the
experimental data starting from a one-parameter fit of the $\pi\pi$ scattering
data.


title: On mixing angles and resonances in three neutrino oscillations in matter

abstract:
  We find exact analytical expressions for mixing angles in matter in the
context of three generation neutrino oscillations in matter to discuss the role
of resonances in this phenomenon. We show that some knowledge from conventional
two neutrino MSW effect, which has been extended to approximated solutions to
three neutrino oscillations, has to be abandoned in this exact approach. We
observe that maximal values for the mixing angles in matter are found in
nonresonant regions and stationary phases do not coincide anymore with
resonances in this simple extension of the MSW effect. We present a general way
to identify a resonance and discuss what we can physically expect in these
regions.


title:
Anomalous violation of the OZI-rule in the $N\bar N\to \Phi\Phi$, $N\bar
  N\to \Phi\gamma$ reactions and instantons

abstract:
  It is shown, that specific properties of the instanton induced interaction
between quarks leads to the anomalous violation of the OZI-rule in the $N\bar
N\to \Phi\Phi$, $N\bar N\to \Phi\gamma$ reactions. In the framework of
instanton model of the QCD vacuum, the energy dependence of the cross sections
of these reactions is calculated.


title: Electron Thermal Self-Energy in a Magnetic Field

abstract:
  Using the general form of the static energy solutions to the Dirac equation
with a magnetic field, we calculate a general self-energy matrix in the
Furry-picture. In the limit of high temperatures, but even higher magnetic
fields, a self-consistent dispersion relation is solved. In contrast to the
high temperature limit, this merely results in a small mass shift. The electron
anomalous magnetic moment is calculated. The contribution from thermal fermions
is found to be different from the corresponding contribution using perturbation
theory and plane-wave external states. In the low temperature limit the
self-energy is shown to exhibit de Haas--van Alphen oscillations. In the limit
of low temperatures and high densities, the self-energy becomes very large.


title: Signals from Flavor Changing Interactions in Extended Models

abstract:
  In the contest of a Two Higgs Doublet Model without flavor conservation, the
presence of Flavor Changing Neutral Scalar Currents may affect in particular
the couplings of the top quark. Some ideas on how to look for new signals from
Flavor Changing Interactions at the next generation of lepton colliders are
presented.


title: Baryons as Solitons in Effective Chiral Field Theories

abstract:
  This lecture comprises some recent developments concerning the description of
baryons as topological solitons in effective chiral meson theories. In the
first part one-loop corrections to the classical tree approximation are
discussed. This involves renormalization of low-energy coupling constants and
evaluation of the finite next-to-leading-order terms in the $1/N_c$ expansion.
Recent results for various nucleon observables are presented. In the second
part electromagnetic nucleon form factors (FFs) with relativistic corrections
are evaluated in a chiral soliton model including vector mesons. The magnetic
FF $G_M^p$ is shown to agree well with new SLAC data for spacelike $Q^2$ up to
30(GeV/c)$^2$ if superconvergence is enforced. The electric FF $G_E^p$ is
dominated by a zero in the few (GeV/c)$^2$ region. The third part describes how
to extract the strong $\pi NN$ form factor from chiral soliton models, taking
due care of the local metric created by the presence of the soliton. When used
in a one-boson-exchange model for the nucleon-nucleon (NN) interaction,
deuteron properties and phase parameters of NN scattering are reproduced as
well as in conventional NN models that apply a hard monopole form factor at the
$\pi NN$ vertex.


title: Complete set of Feynman rules for the MSSM -- ERRATUM

abstract:
  This erratum contains the full corrected version of the paper {\em Complete
set of Feynman rules for the Minimal Supersymmetric Standard Model}, published
in Phys. Rev. D41 (3464) 1990. The complete set of Feynman rules for the
R-parity conserving MSSM is listed, including the most general form of flavour
mixing. Propagators and vertices are computed in t'Hooft-Feynman gauge,
convenient for perturbative calculations beyond the tree level.


title: Small Elements in Fermion Mass Matrices and Anomalous Dipole Moments

abstract:
  Assuming the small entries in the mass matrices are produced by
fermion-scalar loops, we calculate the anomalous dipole moments of the leptons
and quarks. The top quark appears in all the loops as the mass seed. When
comparing the results with experimental data, including electric and magnetic
dipole moments, and radiative transition rates, we obtain the mass limits which
are typically larger than .1 TeV for the relevant neutral scalars, and 70 TeV
for the relevant lepto-quarks. We then discuss the $P-\bar P$ mixing with a toy
model. Rates of the known mixings require the masses of some neutral scalars to
be large.


title: Particle Production in a Hadron Collider Rapidity Gap: The Higgs Case

abstract:
  Production of rare particles within rapidity gaps has been proposed as a
background-free signal for the detection of new physics at hadron colliders. No
complete formalism accounts for such processes yet. We study a simple
lowest-order QCD model for their description. Concentrating on Higgs
production, we show that the calculation of the cross section pp -> pp H can be
embedded into existing models which successfully account for diffractive data.
We extend those models to take into account single and double diffractive cross
sections pp -> H X1 X2 with a gap between the fragments X1 and X2. Using
conservative scenarios, we evaluate the uncertainties in our calculation, and
study the dependence of the cross section on the gap width. We predict that
Higgs production within a gap of 4 units of rapidity is about 0.3 pb for a 100
GeV Higgs at the Tevatron, and almost 2 pb for a 400 GeV Higgs within a gap of
6 units at the LHC with 14 TeV beams.


title: Selectron Searches in $e^-e^-$ Scattering

abstract:
  We review the pair-production and decay of selectrons in $e^-e^-$ collisions
and show how the standard model backgrounds can be virtually eliminated with
polarized beams. The exceedingly simple analysis involved and the large sample
of background-free supersymmetric events make this linear collider operating
mode ideal for discovering selectrons and measuring the mass of the lightest
neutralino.


title: Energy and pressure densities of a hot quark-gluon plasma

abstract:
  We calculate the energy and hydrostatic pressure densities of a hot
quark-gluon plasma in thermal equilibrium through diagrammatic analyses of the
statistical average, $\langle \Theta_{\mu \nu} \rangle$, of the
energy-momentum-tensor operator $\Theta_{\mu \nu}$. To leading order at high
temperature, the energy density of the long wave length modes is consistently
extracted by applying the hard-thermal-loop resummation scheme to the
operator-inserted no-leg thermal amplitudes $\langle \Theta_{\mu \nu} \rangle$.
We find that, for the long wave length gluons, the energy density, being
positive, is tremendously enhanced as compared to the noninteracting case,
while, for the quarks, no noticeable deviation from the noninteracting case is
found.


title:
The $\Delta S = 1$ Weak Chiral Lagrangian as the Effective Theory of the
  Chiral Quark Model

abstract:
  We use the chiral quark model to estimate the coefficients of the weak chiral
lagrangian as obtained from the bosonization of the ten relevant operators of
the $\Delta S = 1$ effective quark lagrangian. All contributions of order
$N_c^2$ as well as $N_c$ and $\alpha_s N_c$ are included. The chiral
coefficients are given in terms of $f_{\pi}$, the quark and gluon condensates
and the scale-dependent NLO Wilson coefficients of the corresponding operators.
In addition, they depend on the constituent quark mass $M$, a parameter
characteristic of the model. The $\gamma_5$-scheme dependence of the chiral
coefficients, computed via dimensional regularization, and the Fierz
transformation properties of the operator basis are discussed in detail. We
apply our result to the evaluation of the hadronic matrix elements for the
decay $K^0 \rightarrow 2 \pi$, consistently including the renormalization
induced by the meson loops. The effect of this renormalization is sizable and
introduces a long-distance scale dependence that matches in the physical
amplitudes the short-distance scale dependence of the Wilson coefficients.


title: Probing Higgs Boson - and Supersymmetry-Induced CP Violation

abstract:
  We consider, both for unpolarized and longitudinally polarized electron
beams, the production of a top quark pair in e+e- collisions with subsequent
semileptonic top and nonleptonic anti-top decay and vice versa and investigate
optimized angular correlations which are sensitive to CP non-conservation in
the top quark production vertex. We calculate these correlations for
two-Higgs--doublet extensions and the minimal supersymmetric extension of the
Standard Model (SM) with CP violation beyond the Kobayashi-Maskawa phase. While
the sensitivity of the optimal correlation for tracing dispersive CP effects is
enhanced with longitudinally polarized electron beams, we find that the
sensitivity of the best correlation for probing absorptive CP effects is almost
independent of the polarization degree.


title:
CP violation in $\eta \to \pi \pi$ by Higgs - $\eta$ mixing through
  two-loop quantum effects

abstract:
  Strictly within the standard electro-weak interaction, CP violation in the
flavour conserving process $\eta \ra \pi + \pi $ could originate from the
mixing of the $\eta$ meson with the virtual scalar Higgs $ H^{0}$ via $
W^{+}+W^{-}$ and $Z^{0}+Z^{0}$ exchange. The parity-violation carried by these
weak gauge bosons makes the mixing possible at two-loop level. Nowhere the
Kobayashi-Maskawa (KM) phase mechanism is needed. For the Higgs mass between
100-600 GeV, the $\eta \ra \pi +\pi $ branching ratio is found to be $3\cdot
10^{-26} - 2\cdot 10^{-29}$, hence unconventional CP violation mechanisms are
the only ones that could give rise to its observation at the existing or near
future $\eta$ factories, unless the Higgs mass is improbably as light as 10
MeV.


title: On the QCD perturbative expansion for e^+ e^- --> hadrons

abstract:
  We study the perturbative QCD series for the hadronic width of the Z boson.
We sum a class of large ``pi^2 terms'' and reorganize the series so as to
minimize ``renormalon'' effects. We also consider the renormalization
scheme-scale ambiguity of the perturbative results. We find that, with three
nontrivial known terms in the perturbative expansion, the treatment of the pi^2
terms is quite important, while renormalon effects are less important. The
measured hadronic width of the Z is often used to determine the value of
alpha_s(M_Z^2). A standard method is to use the perturbative expansion for the
width truncated at order alpha_s^3 in the MS-bar scheme with scale mu = M_Z. We
estimate that the determined value of alpha_s(M_Z^2) should be increased by
0.6% compared to the value extracted with this standard method. After this
adjustment for pi^2 and renormalon effects, we estimate that the uncertainty in
alpha_s(M_Z^2) arising from QCD theory is about 0.4%. This is, of course, much
less than the experimental uncertainty of about 5%.


title: Light Higgsino Detection at LEP1.5

abstract:
  Within the minimal supersymmetric extension of the Standard Model, the best
fit to the most recent precision-measurement data requires charginos and
neutralinos, with dominant Higgsino components and with masses within the reach
of LEP1.5 ($\sqrt{s}=140$ GeV). In this work, we present a detailed analysis of
the neutralino and chargino production processes for the favoured region of
parameter space, that is low values of $|\mu|$ and either low or large values
of $\tan\beta$. We find that chargino and neutralino searches can cover the
Higgsino region in the ($\mu,M_2$) plane for values of $M_2 \simlt 1$ TeV, at
the next phases of the LEP collider. We also show that, due mainly to
phase-space constraints, the lightest neutralinos should be more easily
detectable than charginos in most of the parameter space preferred by
precision-measurement data.


title:
Probing the Chromoelectric and Chromomagnetic dipole moments of the Top
  quark at Hadronic Colliders

abstract:
  We study the effects of the anomalous chromoelectric and chromomagnetic
dipole moments of the top quark on the top-pair production, on the top-pair
plus 1jet production, and on their ratios, as well as their dependence on the
transverse momenta of the top quark and the jet. We also construct CP-odd and
$\hat T$-odd observables to probe the dispersive part of the chromoelectric
form factor of the top quark, and compare their sensitivities in both top-pair
and top-pair plus 1 jet production.


title:
Tensor reduction of two-loop vacuum diagrams and projectors for
  expanding three-point functions

abstract:
  Explicit general formulae for the tensor reduction of two-loop massive vacuum
diagrams are presented. The problem of calculating the corresponding
coefficients is shown to be equivalent to the problem of constructing
differential operators (projectors) extracting the coefficients of the momentum
expansion of massive scalar three-point functions (with any number of loops),
so the solution to the latter problem is also given.


title: The equivalent photon approximation for coherent processes at colliders

abstract:
  We consider coherent electromagnetic processes for colliders with short
bunches, in particular the coherent bremsstrahlung (CBS). CBS is the radiation
of one bunch particles in the collective field of the oncoming bunch. It can be
a potential tool for optimizing collisions and for measuring beam parameters. A
new simple and transparent method to calculate CBS is presented based on the
equivalent photon approximation for this collective field. The results are
applied to the $\phi$--factory $DA\Phi NE$. For this collider about $ 5 \cdot
10^{14} d E_\gamma / E_\gamma$ photons per second are expected in the photon
energy $E_\gamma$ range from the visible light up to 25 eV.


title: The description of F2 at small x incorporating angular ordering

abstract:
  We study the perturbative QCD description of the HERA measurements of $F_2
(x, Q^2)$ using a gluon distribution that is obtained from an evolution
incorporating angular ordering of the gluon emissions, and which embodies both
GLAP and BFKL dynamics. We compare the predictions with recent HERA data for
$F_2$. We present estimates of the charm component $F_2^c (x, Q^2)$ and of $F_L
(x, Q^2)$.


title: Sum Rules for Nucleon Spin Structure Functions

abstract:
  The uncertainties in the perturbative and higher twist corrections to the sum
rules for $\Gamma_{p,n}$ are analyzed. The theoretical predictions for
$\Gamma_{p,n}$ are compared with the whole set of experimental data and the
restrictions on theoretical uncertainties was obtained. Suggestions for future
experiments are given.


title: A Supersymmetric $Sp_{L} \times U_{Y}(1)$ Model

abstract:
  A supersymmetric $Sp_{L}(6) \times U_{Y}(1)$ model (SUSY $Sp(6)$) is proposed
as an extension of the standard electroweak model. The model is applied in a
phenomenological study of $B^{0}_{d} \bar{B}^{0}_{d}$ mixing. It is found that
the supersymmetric (SUSY) partner $\tilde{z}^{\prime}$ of the extra
$Z^{\prime}$ can significantly cancel the other contributions to bring the
mixing parameter $x_{d}$ within the experimentally allowed range $0.57
\stackrel{<}{\sim} x_{d} \stackrel{<}{\sim} 0.77$ for a top mass of $158
\stackrel{<}{\sim} m_{t} \stackrel{<}{\sim} 194$ Gev. Other interesting and
possibly novel features of flavor changing neutral currents (FCNC) in SUSY
theories with horizontal gauge symmetries are pointed out.


title: Flipped SU(5): a Grand Unified Superstring Theory (GUST) Prototype

abstract:
  In this Lecture we first review the basic properties that make flipped SU(5)
a very economical and well motivated unified model, including some recent
developments regarding the prediction for $\alpha_s$ and new implications for
proton decay. Then we sketch the derivation of flipped SU(5) from strings,
stressing some new results concerning the cosmological constant, the stability
of the no-scale mechanism, and a new mechanism for generating the ``LEP" scale
$M_{\rm LEP}\sim10^{16}\GeV$ in string models. Finally we present a sample
supersymmetry breaking scenario, where all sparticle masses depend on a single
parameter, and discuss the experimental signatures at LEP and the Tevatron.
This scenario also predicts the top-quark mass to be close to 175 GeV. (Lecture
presented by D.~V.~Nanopoulos at the 33rd International School of Subnuclear
Physics ``Vacuum and vacua: the physics of nothing", Erice, July 2-10, 1995.)


title: Bc spectroscopy in a quantum-chromodynamic potential model

abstract:
  We have investigated $B_c$ spectroscopy with the use of a
quantum-chromodynamic potential model which was recently used by us for the
light-heavy quarkonia. We give our predictions for the energy levels and the
$E$1 transition widths. We also find, rather surprisingly, that although $B_c$
is not a light-heavy system, the heavy quark effective theory with the
inclusion of the $m_b^{-1}$ and $m_b^{-1}\ln m_b$ corrections is as successful
for $B_c$ as it is for $B$ and $B_s$.


title: Exclusive Semileptonic Tau Decays

abstract:
  We review current issues in exclusive semileptonic tau decays. We present the
formalism of structure functions, and then discuss predictions for final states
with kaons, for decays into four pions and for radiative corrections to the
decay into a single pion. Implications for testing the standard model at low
energies are discussed.


title: Glueballs in Strongly Interacting Theories at the Electroweak Scale

abstract:
  Several proposals for dynamical electroweak symmetry breaking and fermion
mass generation involve strong gauge interactions with a characteristic scale
of a few hundred GeV. The detection of the glueballs which should occur in such
models would be a indication of the non-Abelian nature of the gauge theories
operating at this scale. We discuss signatures for these particles.


title:
QCD Sum Rule Calculation of $\gamma\gamma^*\to\pi^0$ Transition Form
  Factor

abstract:
  We develop a QCD sum rule analysis of the form factor
$F_{\gamma^*\gamma^*\pi^0}(q^2,Q^2)$ in the region where virtuality of one of
the spacelike photons is small $q^2 \ll 1 GeV^2$ while another is large: $Q^2
\gapprox 1 GeV^2$. We construct the operator product expansion suitable for
this kinematic situation and obtain a QCD sum rule for
$F_{\gamma^*\gamma^*\pi^0}(0,Q^2)$. Our results confirm expectation that the
momentum transfer dependence of $F_{\gamma^*\gamma^*\pi^0}(0,Q^2)$ is close to
interpolation between its $Q^2=0$ value fixed by the axial anomaly and $Q^{-2}$
pQCD behaviour for large $Q^2$. Our approach, in contrast to pQCD, does not
require additional assumptions about the shape of the pion distribution
amplitude $\varphi_{\pi}(x)$. The absolute value of the $1/Q^2$ term obtained
in this paper favours $\varphi_{\pi}(x)$ close to the asymptotic form
$\varphi_{\pi}^{as} (x)=6 f_{\pi} x (1-x)$.


title: Master Formula Approach to $\gamma\gamma \to \pi\pi$ processes

abstract:
  We analyze the $\gamma\gamma \to \pi^0\pi^0$ and $\gamma\gamma \to
\pi^+\pi^-$ reactions using the master formula approach to chiral symmetry
breaking. The pertinent vacuum correlators are estimated at tree level, and the
results are compared with one- and two-loop chiral perturbation theory. The
Compton scattering amplitude and the pion polarizabilities are also discussed.


title: Quark-Hadron Duality and Intrinsic Transverse Momentum

abstract:
  It is demonstrated in several exclusive processes involving the pion that a
local quark-hadron duality prescription is equivalent to using an effective $
\bar q q $ (two-body) light-cone wave function $\Psi^{(LD)}(x,k_{\perp})$ for
the pion. This wave function models soft dynamics of all higher $\bar qG \ldots
G q $ Fock components of the standard light-cone approach. Contributions
corresponding to higher Fock components in a hard regime appear in this
approach as radiative corrections and are suppressed by powers of
$\alpha_s/\pi$.


title: Lower Bound on the Pion Polarizability from QCD Sum Rules

abstract:
  Making use of QCD sum rules a lower bound is found which relates the
electromagnetic polarizability $\alpha_{_E}$ and mean-square radius $\langle
r_\pi^2\rangle$ of charged pions through the intrinsic polarizability
$\tilde\alpha_{_E}= \alpha_{_E}-\alpha\langle r_\pi^2\rangle/(3M_\pi)$. We find
that if present constraints on the QCD continuum (duality) threshold are
accepted, this lower bound on the intrinsic polarizability $\tilde\alpha_{_E}$
is incompatible with some previous determinations of $\alpha_{_E}$ and $\langle
r_\pi^2\rangle$.


title: Hard Exclusive Scattering in QCD

abstract:
  We review the theory of hard exclusive scattering in Quantum Chromodynamics.
  After recalling the classical counting rules which describe the leading scale
dependence of form factors and elastic reactions at fixed angle, the
  pedagogical example of the pion form factor is developped in some detail in
order to show explicitely what factorization means in the QCD framework. The
inclusion of transverse degrees of freedom leads to the discussion of Sudakov
effects which are crucial for protecting the calculation from dangerous
infrared regions. The picture generalizes to many hard reactions; a strategy to
extract distribution amplitudes from future data is sketched. We discuss also
the particular case of hadron-hadron collisions where the independent
scattering mechanism dominates asymptotically and where a different
factorization formula applies. We briefly present the concepts of color
transparency and nuclear filtering and critically discuss the few present data
on this subject.


title:
Production and Decay of Neutralinos in the Next-To-Minimal
  Supersymmetric Standard Model

abstract:
  Within the framework of the Next-To-Minimal Supersymmetric Standard Model
(NMSSM) we study neutralino production $e^+e^- \longrightarrow \tilde{\chi}^0_i
\tilde{\chi}^0_j$ ($i,j=1,\ldots ,5$) at center-of-mass energies between 100
and 600 GeV and the decays of the heavier neutralinos into the LSP plus a
fermion pair, a photon or a Higgs boson. For representative gaugino/higgsino
mixing scenarios, where the light neutralinos have significant singlet
components, we find some striking differences between the NMSSM and the minimal
supersymmetric model. Since in the NMSSM neutralino and Higgs sector are
strongly correlated, the decay of the second lightest neutralino into a Higgs
boson and the LSP often is kinematically possible and even dominant in a large
parameter region of typical NMSSM scenarios. Also, the decay rates into final
states with a photon may be enhanced.


title: Moduli Effects on Neutrino Oscillations

abstract:
  We point out the possibility to detect the low-energy signals of moduli in
the superstring theory through the neutrino oscillation. The idea is based on
the characteristics that the couplings of moduli are different from matter to
matter. We estimate the oscillation probability both in the baseline and solar
neutrino oscillations. In both cases, when there is at least one modulus of
which mass is less than or equal to $10^{-19}$ GeV, the interaction of the
modulus significantly changes the conversion probability from one neutrino
flavor to another.


title: Reply to Comment on ``Dynamics of Weak First Order Phase Transitions''

abstract:
  A reply to a Comment by Harris and Jungman (Phys. Rev. Lett. 75 (1995), 588),
concerning my work on phase mixing and its implications to the dynamics of
``weak'' first order phase transitions.


title:
Isospin Violation and Possible Signatures of Disoriented Chiral
  Condensates in Ultrarelativistic Heavy Ion Collisions

abstract:
  It is possible that isospin violating dynamical effects are amplified due to
coherence if a disoriented chiral condensate (or other source of a coherent
pion state) is formed in a heavy ion collison. It is shown explicitly that
altering the isospin of the coherent state by order of one unit can change the
number of $\pi^0$'s in the condensate by some finite fraction of the total
number. A possible signature of such amplified isospin violating effects is
that the ratio of neutral to total low $p_T$ pions averaged over many events
may differ markedly from 1/3. Such a signal would not be washed out if multiple
domains of coherent pions form.


title: Four-Fermi Effective Operators at e^+ e^- ---> \bar{t} t

abstract:
  The process of top quark pair production at Next Linear Collider (NLC) has
been considered adopting an effective Lagrangian approach and including all
operators of dim~6 which can be tree-level-generated within unknown underlying
theory. All contributing helicity amplitudes are presented. It has been found
that four-fermion operators can provide the leading non-standard contribution
to the total cross section. Expected statistical significance of the
non-standard signal for the total cross section and forward-backward asymmetry
have been calculated taking into account existing experimental constraints. It
has been shown that adopting realistic luminosity of NLC and conservative
efficiency for the top-quark pair detection, the total cross section may be
sensitive to non-standard physics of an energy scale around $\Lambda=5\tev$.


title:
Gauge Coupling Unification and the Top Mass in String Models with
  $SU(4)\times O(4)$ Symmetry

abstract:
  We discuss the low energy implications of gauge coupling unification at the
string scale, taking into account string threshold corrections in the $SU(4)
{\times} O(4)$ model. We express $sin^2\theta_W$ and $a_3$ as functions of the
calculable string threshold differences and discuss simple examples of spectra
which retain the successful predictions of the supersymmetric unification.
Using further the low energy data and reasonable values of the common gauge
coupling at the string scale, we obtain the range of the threshold corrections.
Finally, we study the top Yukawa coupling ($h_t$) evolution whose initial value
is determined in terms of the common gauge coupling at the string scale. We
find that $h_t$ reaches its (quasi) infra-red fixed point at the weak scale and
discuss the implications on the top mass.


title:
Which Bosonic Loop Corrections are Tested in Electroweak Precision
  Measurements?

abstract:
  The nature of the electroweak bosonic loop corrections to which current
precision experiments are sensitive is explored. The set of effective
parameters $\De x$, $\De y$, and $\eps$, which quantify SU(2) violation in an
effective Lagrangian, is shown to be particularly useful for this purpose. The
standard bosonic corrections are sizable only in the parameter $\De y$, while
$\De x$ and $\eps$ are sufficiently well approximated by the pure fermion-loop
prediction. By analyzing the contributions to $\De y$ it is shown that the
bosonic loop corrections resolved by the present precision data are induced by
the change in energy scale between the low-energy process muon decay and the
energy scale of the LEP1 observables. If the (theoretical value of the)
leptonic width of the W boson is used as input parameter instead of the Fermi
constant $\GF$, no further bosonic loop corrections are necessary for
compatibility between theory and experiment.


title: Some Phenomenology of the top quark with non-standard couplings

abstract:
  In this talk I will use effective lagrangian and discuss possible new physics
associated with top quark.


title: Probing Nucleon Structure via High Energy Elastic Scattering

abstract:
  Analyses of high energy elastic pp and $\bar pp$ scattering data from CERN
ISR and SPS Collider seem to provide strong evidence in favor of the gauged
nonlinear sigma-model of the nucleon. This model describes the nucleon as a
topological soliton and introduces the vector mesons omega, rho, a1 as gauge
bosons. The model, however, needs to be extended to include an explicit quark
sector, where left and right quarks interact via a scalar field. A critical
behavior of the scalar field results in a phase transition to a condensed
quark-antiquark ground state. The latter can provide the outer cloud of the
nucleon, which is responsible for diffraction scattering. If the nucleon is
probed deeper via high energy elastic scattering, then evidence for the phase
transition may emerge from a rapid change in the behavior of the differential
cross-section.


title: Low Energy Implications of Minimal Superstring Unification

abstract:
  We study the phenomenological implications of effective supergravities based
on string vacua with spontaneously broken N=1 supersymmetry by dilaton and
moduli $F$-terms. We further require Minimal String Unification, namely that
large string threshold corrections ensure the correct unification of the gauge
couplings at the grand unification scale. The whole supersymmetric mass
spectrum turns out to be determined in terms of only two independent
parameters, the dilaton-moduli mixing angle and the gravitino mass. In
particular we discuss the region of the parameter space where at least one
superpartner is ``visible" at LEP2. We find that the most likely candidates are
the scalar partner of the right-handed electron and the lightest chargino, with
interesting correlations between their masses and with the mass of the lightest
higgs. We show how discovering SUSY particles at LEP2 might rather sharply
discriminate between scenarios with pure dilaton SUSY breaking and mixed
dilaton-moduli breaking.


title: Neutral Kaons without Weisskopf-Wigner Approximation

abstract:
  The model-independent formalism is constructed to describe decays of mixed
particles without using the Weisskopf-Wigner approximation. Limitations due to
various symmetries are traced for neutral $K-$mesons. As an application we show
that effects of $CPT-$violation and going beyond WWA may be separated and
studied independently.


title: Intermediate Energy Solar Neutrinos

abstract:
  We extract information on the fluxes of Be and CNO neutrinos directly from
solar neutrino experiments, with minimal assumptions about solar models. Next
we compare these results with solar models, both standard and non standard
ones. Finally we discuss the expectations for Borexino, both in the case of
standard and non standard neutrinos.


title: Search for Tensor Interactions in Kaon Decays at DA$\Phi$NE

abstract:
  The semileptonic kaon decays $K_{l2\gamma}$ and $K_{l3}$ are considered. We
use the most general forms of the matrix elements for these decays. Additional
terms could arise as a result of new tensor interactions between quarks and
leptons. Such terms have been detected in a recent experiments. The high
precision experiments at DA$\Phi$NE may be ideal to confirm these results.


title:
Neutrino Masses and Mixing Angles in SUSY-GUT Theories with explicit
  R-Parity Breaking

abstract:
  In minimal SUSY GUT models the $R$-parity breaking terms are severely
constrained by SU(5) gauge invariance. We consider the particular case where
the explicit $R$-parity breaking occurs only via dimension 2 terms of the
superpotential. This model possesses only three R-parity breaking parameters.
We have studied the predictions of this model for the neutrino masses and
mixing angles at the one-loop level within the framework of a radiatively
broken unified supergravity model. We find that this model naturally yields
masses and mixing angles that can explain the solar and atmospheric neutrino
problems. In addition, there are regions in parameter space where the solution
to the solar neutrino puzzle is compatible with either the LSND result or the
existence of significant hot dark matter neutrinos.


title: One-loop corrections to the top, stop and gluino masses in the MSSM

abstract:
  We compute the one-loop radiative corrections to the masses of the top quark,
the stop squarks and the gluino in the Minimal Supersymmetric Standard Model.
We include the loops controlled by the strong coupling constant and the top
Yukawa coupling, neglecting those controlled by the $SU(2) \times U(1)$ gauge
couplings and by other Yukawa couplings. We find that the significant
scale-dependence of the renormalization-group-improved tree-level expressions
is almost completely removed. Even for natural choices of the renormalization
scale, corrections can be numerically relevant. Our results should allow more
reliable predictions to be extracted from candidate fundamental theories beyond
the MSSM.


title:
Radiative $B^{*}\to B\gamma$ and $D^{*}\to D\gamma$ decays in light cone
  QCD sum rules

abstract:
  The radiative decays $ B^{*} (D^{*})\rightarrow B(D) \gamma$ are investigated
in the framework of light cone QCD sum rules. The transition amplitude and
decay rates are estimated.It is shown that our results on branching ratios of D
meson decays are in good agreement with the existing experimental data.


title: The path integrals on a curved manifold

abstract:
  For description of the quantum dynamics on a curved group manifold the path
integrals in a space of the group parameters is offered. The formalism is
illustrated by the $H$-atom problem.


title:
Supersymmetric QCD corrections to the top quark decay of a heavy charged
  higgs boson

abstract:
  The supersymmetric QCD corrections to the hadronic width of a heavy charged
Higgs boson, basically dominated by the top-quark decay mode $H^{+}\rightarrow
t \bar{b}$, are evaluated at ${\cal O}(\alpha_s)$ within the MSSM and compared
with the standard QCD corrections. The study of such quantum effects, which
turn out to be rather large, is essential to understand the hypothetical
supersymmetric nature of a heavy charged Higgs boson potentially produced in
the near future at the Tevatron and/or at the LHC.


title:
Supersymmetry and Gauge Invariance Constraints in a U(1)$\times
  $U(1)$^{\prime }$-Higgs Superconducting Cosmic String Model

abstract:
  A supersymmetric extension of the $U(1)\times U(1)^{\prime }$-Higgs bosonic
superconducting cosmic string model is considered,and the constraints imposed
upon such a model due to renormalizability, supersymmetry, and gauge invariance
are examined. For a simple model with a single $U(1)$ chiral superfield and a
single $% U(1)^{\prime }$ chiral superfield, the Witten mechanism for bosonic
superconductivity (giving rise to long range gauge fields outside of the
string) does not exist. The simplest model that can accommodate the requisite
interactions requires five chiral supermultiplets. This superconducting cosmic
string solution is investigated.


title: Comment on "EPR without `collapse of the wave functions'"

abstract:
  The implication of the many time formalism for the process $\Phi$
$\rightarrow$ $K^0 \ + {\bar K}^0$ was discussed in a recent letter of B.
Kayser and L. Stodolsky who predicted a small correction ($\sim\ 5 \%$) to the
usually predicted phase ocillations frequency for forthcoming $\Phi$ factory
experiments. Based on previous work (also using the many proper times
formalism), we predicted a much larger correction $\sim \ 2$. This correction
factor is important in that it allows for a crucial future $DA \Phi NE$
experimental test of the many proper times amplitude formalism.


title:
On The Absence Of Open Strings In A Lattice-Free Simulation Of Cosmic
  String Formation

abstract:
  Lattice-based string formation algorithms can, at least in principle, be
reduced to the study of the statistics of the corresponding aperiodic random
walk. Since in three or more dimensions such walks are transient this approach
necessarily generates a population of open strings. To investigate whether open
strings are an artefact of the lattice we develop an alternative lattice-free
simulation of string formation. Replacing the lattice with a graph generated by
a minimal dynamical model of a first order phase transition we obtain results
consistent with the hypothesis that the energy density in string is due to a
scale-invariant Brownian distribution of closed loops alone.


title: Heavy Baryons and Multiquark Exotics in the Large $N_c$ limit

abstract:
  In the large $N_c$ limit, one can describe normal heavy baryons $Qqq$ and
heavy pentaquarks $\bar Qqqqq$ as bound states of heavy mesons to chiral
(anti)solitons. In this picture, the strong and electromagnetic decay
parameters of these hadrons can be calculated from those of the constituent
heavy mesons and light baryons, while the weak decay form factors can be
evaluated analytically.


title: Higgs triplet effects in purely leptonic processes

abstract:
  We consider the effect of complex Higgs triplets on purely leptonic processes
and survey the experimental constraints on the mass and couplings of their
single and double charge members. Present day experiments tolerate values of
the Yukawa couplings of these scalars at the level of the standard electroweak
gauge couplings. We show that the proposed measurement of the ratio
$R_{LCD}=\sigma (\nu_{\mu}e)/ [\sigma (\bb\nu_{\mu}e) + \sigma (\nu_e e )]$
would allow to explore a large region of the parameter space inaccessible to
the usual ratio $R=\sigma (\nu_{\mu}e)/\sigma (\bb\nu_{\mu}e)$.


title:
Study of Anomalous Couplings at a $500$~GeV $e^+e^-$ Linear Collider
  with Polarized Beams

abstract:
  We consider the possibility of observing deviations from the Standard Model
gauge-boson self-couplings at a future $500$~GeV $e^+ e^-$ linear collider. We
concentrate on the case in which the electroweak symmetry breaking sector is
strongly interacting and there are no new resonances within reach of the
collider. We find a sensitivity to the anomalous couplings that is two orders
of magnitude higher than that achievable at LEP II. We also show how a
polarized electron beam extends the reach of the collider, allowing experiments
to probe different directions in parameter space.


title: Instanton contribution to the quark distribution functions

abstract:
  The instanton contribution to the quark distribution functions in the nucleon
is estimated. It is shown, that taking into account the instanton induced
interaction between quarks allows to explain the anomalous violation of the
Ellis-Jaffe and Gottfried sum rules. The spin-dependent structure functions
$g_1^p(x)$, $g_1^n(x)$, $g_1^d(x)$ are calculated in the framework of the
instanton model of the QCD vacuum.


title:
Role of beam polarization in the determination of $WW\gamma$ and $WWZ$
  couplings from $e^+e^-\to W^+W^-$

abstract:
  We evaluate the constraints on anomalous trilinear gauge-boson couplings that
can be obtained from the study of electron-positron annihilation into $W$ pairs
at a facility with either the electron beam longitudinally polarized or both
electron and positron beams transversely polarized. The energy ranges
considered in the analysis are the ones relevant to the next-linear collider
and to LEP~200. We discuss the possibilities of a model independent analysis of
the general $CP$ conserving anomalous effective Lagrangian, as well as its
restriction to some specific models with reduced number of independent
couplings. The combination of observables with initial and final state
polarizations allows to separately constrain the different couplings and to
improve the corresponding numerical bounds.


title:
Compositeness Condition at the Next-to-Leading Order in the
  Nambu-Jona-Lasinio Model

abstract:
  We investigate the compositeness condition in four dimensions at the
non-trivial order (next-to-leading order in $1/N$ with the number $N$ of the
colors), taking the Nambu-Jona-Lasinio model as an example. In spite of its
non-renormalizability, the compositeness condition can be successfully derived
and solved in compact forms. The resultant problems are discussed.


title:
Universal Mass Dependence for Particle Production Rates in $e^+e^-$,
  $pp$ and $AA$ Collisions from the Quark-Gluon Plasma Perspective

abstract:
  It is demonstrated that universal mass dependence for meson and baryon
inclusive cross-sections advocated recently in $e^+e^-$ annihilation and in
hadronic reactions is consistent also with heavy ion collisions data and can
therefore be used as a reference for quark-gluon plasma studies.


title: QCD and experiment on multiplicity distributions

abstract:
  The solution of QCD equations for generating functions of {\it parton}
multiplicity distributions reveals new peculiar features of cumulant moments
oscillating as functions of their rank. It happens that experimental data on
{\it hadron} multiplicity distributions in $e^{+}e^{-}, hh, AA$ collisions
possess the similar features. However, the "more regular" models like $\lambda
\phi ^3$ behave in a different way. Evolution of the moments at smaller phase
space bins and zeros of the truncated generating functions are briefly
discussed.


title: The Top-Bottom Hierarchy from Gauge-Yukawa Unification

abstract:
  The idea of Gauge-Yukawa Unification (GYU) based on the principle of
reduction of couplings is elucidated. We show how the observed top-bottom mass
hierarchy can be explained in terms of supersymmetric GYU by considering an
example of the minimal supersymmetric GUT.


title: Electric dipole moments as signals of supersymmetric unification

abstract:
  If supersymmetric unification is true, we show how the combined effort of
several experiments under way to try to measure an electric dipole moment of
the electron or of the neutron has a significant chance not only of producing a
positive signal but also of providing crucial information to understand the
physical origin of the signal itself.


title: W+2jets production at Tevatron -- VECBOS and CompHEP comparison

abstract:
  Results of calculation of all subprocesses in proton-antiproton collisions
which contribute to the W+2jets final state are presented at Tevatron energy.
The calculation has been carried out by means of the CompHEP software package.
A detail comparison with VECBOS generator results for cross sections and
various distributions shows an agreement at the level of Monte-Carlo accuracy.
Therefore the additional independent check of VECBOS generator has been done.
In complement to the VECBOS generator a new generator based on CompHEP allows
to study individual subprocesses like $Wb\bar{b}$ or $Wc\bar{c}$. The last
point is important, for instance, for study $Wb\bar{b}$ part of the background
for single top or Standard Model Higgs signal at Tevatron.


title: The Derivation of $M_{GUT}=10^{16}GeV$ from A String Model

abstract:
  We propose that gaugino condensation in the hidden sector may dynamically
induce intermediate gauge symmetry breaking and specify the compactification
scale. We also show that this scheme makes possible affine level one grand
unified string models with gauge breaking scale $M_{\rm GUT} \sim 10^{16}$ GeV.
$T$-duality plays a crucial role in making this scheme possible, even though it
is spontaneously broken. We also discuss the generation of the large mass
hierarchy between the string scale and the electroweak scale and the solution
of the dilaton runaway problem in this scheme.


title:
$e^+e^- \to b\bar b W^+W^-$ events at the Next Linear Collider: colour
  structure of top signal and irreducible background

abstract:
  We examine the colour structure and charged particle yield for both the $t
\bar t$ signal and the irreducible background processes contributing to
\eebbww\ production close to the \ttb\ threshold. The charged particle
multiplicity for the various components of the cross section is computed as a
function of several kinematic variables. Our study may have important
implications for recently proposed studies of interconnection phenomena in
\ttb\ production at high--energy $e^+e^-$ colliders


title: Large-N_c Relations Among Isgur-Wise Functions

abstract:
  We investigate the relations that must hold among baryonic Isgur-Wise
functions $\eta_i$ in the large-N_c limit from unitarity constraints, and
compare to those found by Chow using the Skyrme model [or SU(4)]. Given the
exponential dropoff of the $\eta_i$ away from threshold, unitarity requires
only that the usual normalization conditions hold at w=1, and that
$\eta=\eta_1$ near threshold. Our results are consistent with, but less
powerful than, the Skyrme model relations.


title:
Two-loop $O(N_f\alpha _s^2)$ correction to the decay width of the Higgs
  boson to two massive fermions

abstract:
  We present an analytical calculation of additional real or virtual radiation
of the light fermion pair in the fermionic decay of the Higgs boson $ H \to
f_1\bar f_1$ for arbitrary ratios of the Higgs boson mass to the $f_1$ fermion
mass.
  This result gives us a value of the $O(N_f \alpha _s^2)$ radiative correction
to the inclusive decay rate $ H \to f_1\bar f_1$. Using this result in the
framework of the Brodsky-Mackenzie-Lepage scheme, we discuss the scale setting
in the one-loop QCD correction to the decay width $ H \to f_1\bar f_1$ for
arbitrary relation between the Higgs boson and fermion masses.


title: Semi-Inclusive Deeply Inelastic Scattering at Small q_T

abstract:
  Measurement of the distribution of hadronic energy in the final state in
deeply inelastic electron scattering at HERA can provide a good test of our
understanding of perturbative QCD. For this purpose, we consider the energy
distribution function, which can be computed without needing final state parton
fragmentation functions. We compute this distribution function for finite
transverse momentum q_T at order alpha_s, and use the results to sum the
perturbation series to obtain a result valid for both large and small values of
transverse momentum.


title: Quark-Lepton Masses and the Ckm Matrix in a String Inspired Model

abstract:
  In the context of the Calabi-Yau string model we discuss the origin of
characteristic pattern of quark-lepton masses and the CKM matrix. The discrete
$R$-symmetry $Z_{2k+1} \times Z_2$ is introduced and the $Z_2$ is assigned to
the $R$-parity. The gauge symmetry at the string scale is broken into the
standard model gauge group at an intermediate energy scale. At energies below
the intermediate scale down-type quarks and also leptons are mixed with
unobserved heavy states, respectively. On the other hand, there are no such
mixings for up-type quarks. The large mixings between light states and heavy
ones cause different mass pattern of leptons and down-type quarks from that of
up-type quarks and yield a nontrivial CKM matrix for quarks but a trivial one
for leptons. The mixing mechanism is illustrated using a two-generation toy
model.


title: Phenomenological aspects of supersymmetry

abstract:
  We discuss the possible applications supersymmetric theories might find in
the field of elementary particle physics. The supersymmetric generalization of
the $SU(3)\times SU(2)\times U(1)$ standard model is discussed in detail.
Special attention has been devoted to the question of gauge coupling constant
unification in the framework of supersymmetric grand unified models.


title: A Strong QCD Enhancement of CP Violation in Charmed Meson Decays?

abstract:
  The mass difference of $c$ and $u$ quarks is similar to the energy needed to
excite gluonic degrees of freedom in strong QCD. This underpins the degeneracy
of $D$ and a recently observed candidate hybrid excitation of the $\pi$ at$\sim
1.8$GeV and may generate a strong analogue of Penguin mixing together with a
measurable CP-violation in $D$ and $D_s$ decays.


title: Color-octet quarkonia production II

abstract:
  We calculate the lowest order hadronic cross sections for producing colored
heavy quark-antiquark pairs in $L=S=0$ and $L=S=1$ configurations. Such
$Q\Qbar[{}^1S_0^{(8)}]$ and $Q\Qbar[{}^3P_J^{(8)}]$ states hadronize into
$\psi_\Q$ quarkonia at the same order in the NRQCD velocity expansion as
previously considered $Q\Qbar[{}^3S_1^{(8)}]$ pairs. Their contributions to
prompt Psi and Upsilon production at the Tevatron bring the shapes of
theoretical transverse momentum distributions into line with recent CDF
measurements. We find that the best fit values for the linear combinations of
$Q\Qbar[{}^1S_0^{(8)}]$ and $Q\Qbar[{}^3P_J^{(8)}]$ long distance matrix
elements which can be extracted from the data are generally consistent with
NRQCD scaling rules.


title: $\eta$ Production in Peripheral Heavy-Ion Collisions

abstract:
  We estimate the impact parameter dependence of the production cross section
for $\eta_c$ and $\eta_b$ mesons in peripheral heavy-ion collisions collisions.
Total and elastic $\gamma\gamma$ cross sections are calculated in an equivalent
photon approximation.


title: Low-Energy Supersymmetry Breaking and Fermion Mass Hierarchies

abstract:
  In models with low-energy supersymmetry breaking, an anomalous Abelian
horizontal gauge symmetry can simultaneously explain the fermion mass hierarchy
and the values of the $\mu$ and $B$ terms. We construct an explicit model where
the anomaly is cancelled by the Green-Schwarz mechanism at the string scale. We
show that with our charge assignments, the breaking of the horizontal symmetry
generates the correct order of magnitude and correct hierarchy for all Yukawa
couplings.


title: A Covariant Method for Calculating Helicity Amplitudes

abstract:
  We present an alternative approach for calculating helicity amplitudes for
processes involving both massless and massive fermions. With this method one
can easily obtain covariant expressions for the helicity amplitudes. The final
expressions involve only four vector products and are independent of the basis
for gamma matrices or specific form of the spinors. We use the method to obtain
the helicity amplitudes for several processes involving top quark production.


title:
Detection of the Minimal Supersymmetric Model Higgs Boson $H^0$ in its
  $h^0h^0\to 4b$ and $A^0A^0\to 4b$ Decay Channels

abstract:
  We demonstrate that detection of the heavier minimal supersymmetric model
CP-even Higgs boson $H^0$ will be possible at the LHC via its $H^0\to h^0h^0\to
4b$ and/or $H^0\to A^0A^0\to 4b$ decay channels for significant portions of the
$( m_{A^0},\tan\beta)$ model parameter space. At low $ m_{A^0}$ ($\lsim
60\gev$), {\it both} the $H^0\to A^0A^0\to 4b$ and $H^0\to h^0h^0\to 4b$ modes
yield a viable signal for most $\tan\beta$ values; viability for the $h^0h^0$
channel extends up to $\mhh\sim 2\mt$ when the model parameter $\tan\beta$ is
not large. At the Tevatron, the $h^0h^0$ and $A^0A^0$ channels are both
potentially viable at low $ m_{A^0}$ for sufficiently good $b$-tagging
efficiency and purity.


title: Chiral Lagrangians for Baryons coupled to massive Spin-1 Fields

abstract:
  We analyze the effective low--energy field theory of Goldstone bosons and
baryons chirally coupled to massive spin--1 fields. We use the electromagnetic
baryon form factors to demonstrate the formal equivalence between the vector
and the tensor field formulation for the spin--1 fields. We also discuss the
origin of the so--called Weinberg term in pion--nucleon scattering and the role
of $\rho$--meson exchange. Chirally coupled vector mesons do not give rise to
this two--pion nucleon seagull interaction but rather to higher order
corrections. Some problems of the formal equivalence arising in higher orders
and related to loops are touched upon.


title:
Space, Time and Color in Hadron Production Via e+e- -> Z0 and e+e- ->
  W+W-

abstract:
  The time-evolution of jets in hadronic e+e- events at LEP is investigated in
both position- and momentum-space, with emphasis on effects due to color flow
and particle correlations. We address dynamical aspects of the four
simultanously-evolving, cross-talking parton cascades that appear in the
reaction e+e- -> gamma/Z0 -> W+W- -> q1 q~2 q3 q~4, and compare with the
familiar two-parton cascades in e+e- -> Z0 -> q1 q~2. We use a QCD statistical
transport approach, in which the multiparticle final state is treated as an
evolving mixture of partons and hadrons, whose proportions are controlled by
their local space-time geography via standard perturbative QCD parton shower
evolution and a phenomenological model for non-perturbative parton-cluster
formation followed by cluster decays into hadrons. Our numerical simulations
exhibit a characteristic `inside-outside' evolution simultanously in position
and momentum space. We compare three different model treatments of color flow,
and find large effects due to cluster formation by the combination of partons
from different W parents. In particular, we find in our preferred model a shift
of several hundred MeV in the apparent mass of the W, which is considerably
larger than in previous model calculations. This suggests that the
determination of the W mass at LEP2 may turn out to be a sensitive probe of
spatial correlations and hadronization dynamics.


title:
On the Connection between Generalized Hypergeometric Functions and
  Dilogarithms

abstract:
  Several integrals involving powers and ordinary hypergeometric functions are
rederived by means of a generalized hypergeometric function of two variables
(Appell's function) recovering some well-known expressions as particular cases.
Simple connections between dilogarithms and a kind of Appell's function are
shown. A relationship is generalized to polylogarithms.


title: Sterile neutrinos and supernova nucleosynthesis

abstract:
  The role of the sterile neutrinos to the r-process nucleosynthesis in
supernova explosions is studied. Previously it has been argued that a large
part of neutrino mixing can be excluded if the supernovae are the origin of the
heavy elements. It is shown that a conversion to sterile neutrinos may evade
those limits. The possibility that such conversions can enhance the
nucleosynthesis is investigated. The desired mass spectrum is consistent with
neutrino masses suggested by other observed phenomena, like the solar neutrino
problem, the atmospheric neurino problem, dark matter and the LSND signals.


title: The Light Higgsino-Gaugino Window

abstract:
  Supersymmetric models are typically taken to have $\mu$ parameter and all
soft supersymmetry breaking parameters at or near the weak scale. We point out
that a small window of allowed values exists in which $\mu$ and the electroweak
gaugino masses are in the few GeV range. Such models naturally solve the
supersymmetry $CP$ problem, can reduce the discrepancy in $R_b$, and suppress
proton decay. In this window two neutralinos are in the few GeV range, two are
roughly degenerate with the $Z^0$, and both charginos are roughly degenerate
with the $W^{\pm}$ bosons. Such a signature cannot escape detection at LEP II.
Models that fall in this window automatically arise from renormalizable hidden
sectors in which hidden sector singlets participate only radiatively in
supersymmetry breaking.


title:
Spin-dependent structure functions $\hat g_1$ and $\hat g_2$ for
  inclusive spin-half baryon production in electron-positron annihilation

abstract:
  Two spin-dependent structure functions $\hat g_1$ and $\hat g_2$ for the
inclusive spin-half baryon production in electron-positron annihilation are
studied in the context of QCD factorization as well as in the naive quark
parton model. As a result, it is found that the sum of $\hat g_1$ and $\hat
g_2$ is related to $\hat h_1$ and $\hat g_T$, two quark fragmentation functions
defined by Jaffe and Ji. In connection with the measurement of quark
fragmentation functions, the possible phenomenological consequences are
discussed.


title:
The electric dipole moment of the neutron in the constrained minimally
  supersymmetric standard model

abstract:
  We analyse the electric dipole moment of the neutron in the MSSM, induced by
the renormalisation of the soft-susy breaking terms. We run the RGEs using
two-loop expressions for gauge and Yukawa couplings and retaining family
dependence. The $\mu$ and $B$ parameters were determined by minimising the full
one-loop Higgs potential, and we find that the neutron EDM lies in the range
$10^{-33}<|d_n| < 10^{-29} {\; e\;\mbox{cm}} $.


title:
CP Violation, Fermion Masses and Mixings in a Predictive SUSY SO(10) X
  Delta (48) X U(1) Model with Small tan(beta)

abstract:
  Fermion masses and mixing angles are studied in an SUSY $SO(10)\times \Delta
(48)\times U(1)$ model with small $\tan\beta$. Thirteen parameters involving
masses and mixing angles in the quark and charged lepton sector are
successfully predicted by a single Yukawa coupling and three ratios of VEVs
caused by necessary symmetry breaking. Ten relations among the low energy
parameters have been found with four of them free from renormalization
modifications. They could be tested directly by low energy experiments.


title:
Need for the intensity-dependent pion-nucleon coupling in multipion
  production processes

abstract:
  We give reasons in support of the use of an effective intensity-dependent
pion-nucleon coupling Hamiltonian for describing the properties of the pion
multiplicity distribution and the corresponding factorial moments within the
thermal-density matrix approach.We explain the appearance of the
negative-binomial (NB) distribution for pions and the well-known empi- rical
relation of Wroblewski.Our model Hamiltonian is written as a linear combination
of the generators of the SU(1,1) group.We find the generating function for the
pion multiplicity distribution at finite temperature T and discuss the
properties of the second-order factorial moment.Also, we show that an
intensity-dependent pion-nucleon coupling generates the squeezed states of the
pion field. At T=0, these squeezed states become an inherent property of the NB
distribution.


title: A Two Higgs Doublet Model for the Top Quark

abstract:
  A two Higgs doublet model with special Yukawa interactions for the top quark
and a softly broken discrete symmetry in the Higgs potential is proposed. In
this model, the top quark is much heavier than the other quarks and leptons
because it couples to a Higgs doublet with a much larger vacuum expectation
value. The electric dipole moment (EDM) of the electron is evaluated with loop
diagrams of the third generation fermions as well as the charm quark. The
electron EDM is significantly enhanced for a naturally large $\tan\beta \equiv
|v_2|/|v_1|$.


title: Perturbative Evolution of Polarized Structure Functions

abstract:
  We review the perturbative evolution of the polarized structure functions g_1
and their associated parton distribution functions, with particular emphasis on
the anomalous coupling of the first moment of the polarized gluon distribution.
We also describe the small x behaviour of polarized parton distributions,
contrasting it with that of the unpolarized distributions. We then explain how
this theoretical analysis affects the extraction of the singlet axial charge
from experimental data on g_1, and show that it may be possible to use such
data to infer the existence of polarized gluons in the nucleon.


title: J/Psi Suppression in an Equilibrating Parton Plasma

abstract:
  Short-distance QCD is employed to calculate the $J/\psi$ survival probability
in an equilibrating parton gas, whose evolution is governed by a set of master
rate equations. Partons in the early stage of high-energy nuclear collisions
may initially not be in equilibrium, but their average transverse momentum is
sufficiently high to break up a $Q\bar{Q}$ bound state. Such a break-up during
the evolution of the parton gas is shown to cause a substantial $J/\psi$
suppression at both RHIC and LHC energies, using realistic estimates of the
initial parton densities. The transverse momentum dependence of the suppression
is also shown to be sensitive to the initial conditions and the evolution
history of the parton plasma.


title: Unitarized model of hadronic diffractive dissociation

abstract:
  It is shown that in a supercritical pomeron model the contribution of the
tirple-pomeron diagrams violates the unitarity bound for cross-section even
with account of the multiple pomeron exchanges between the initial hadrons.
Asymptotic behaviour of the single diffractive dissoci\-ation cross-section is
calculated in the approximation where every pomeron in the $3P$-diagram is
eikonalized as well as an elastic interaction of initial hadrons is taken into
account. In this approximation $\sigma^{SD}/\sigma_{tot}\rightarrow 0$ at
$s\rightarrow \infty.$


title: Quantum Color Transparency and Nuclear Filtering

abstract:
  Color transparency is the proposal that under certain circumstances the
strong interactions can be reduced in magnitude. We give a comprehensive review
of the physics, which hinges on the interface of perturbative QCD with
non--perturbative strong interactions. Color transparency is complementary to
{\it nuclear filtering}, which is the conversion of quark wave functions in
hadrons to small transverse space dimensions by interaction with a nuclear
medium. We review current approaches, including pictures based on modeling the
time evolution of hadronic wave--packets as well as the use of light cone
matrix elements. Spin plays an intrinsic role in testing and understanding the
physics and is discussed at length. We emphasize the use of data analysis
procedures which have minimal model dependence. We also review existing
experimental data and the experimental program planned at various facilities.
The subject has strong scientific complementarity and potential to make
progress in exploring hadron physics at current and future facilities.


title: On Low-Energy Theory from General Supergravity

abstract:
  Starting from non-minimal supergravity theory with unified gauge symmetry, we
obtain the low-energy effective theory by taking the flat limit and integrating
out the superheavy fields in a model-independent manner. The scalar potential
has extra non-universal contributions to soft supersymmetry breaking terms
which can give an impact on phenomenological study.


title: Simple Description of Pion-Pion Scattering to 1 GeV

abstract:
  Motivated by the 1/Nc expansion, we present a simple model of pion-pion
scattering as a sum of a `current-algebra' contact term and resonant pole
exchanges. The model preserves crossing symmetry as well as unitarity up to 1.2
GeV. Key features include chiral dynamics, vector meson dominance, a broad low
energy scalar (sigma) meson and a `Ramsauer-Townsend' mechanism for the
understanding of the 980 MeV region. We discuss in detail the `regularization'
(corresponding to rescattering effects) necessary to make all these nice
features work.


title: Massive Loop Amplitudes from Unitarity

abstract:
  We show, for previously uncalculated examples containing a uniform mass in
the loop, that it is possible to obtain complete massive one-loop gauge theory
amplitudes solely from unitarity and known ultraviolet or infrared mass
singularities. In particular, we calculate four-gluon scattering via massive
quark loops in QCD. The contribution of a heavy quark to five-gluon scattering
with identical helicities is also presented.


title: Top-Charm Strong Flavor-Changing Neutral Currents at the Tevatron

abstract:
  The possibility of an anomalous coupling between the top and charm quarks and
the gluon field is explored in a model-independent way using an effective
Lagrangian that is gauge-invariant under a non-linear realization of SU(3)$_{C}
\times$ SU(2$)_{L} \times$ U(1$)_{Y}$. Even for the current 200 $pb^{-1}$ of
integrated luminosity at the Tevatron, the new physics scale that strongly
modifies the coupling of t-c-g must be larger than about 2.5 TeV if no signal
is found within a 3$\sigma$ confidence limit. For 1 $fb^{-1}$ of data, this
constraint can be pushed up to 3.8 TeV.


title: Precision Study of MSSM at future $e^+e^-$ linear colliders

abstract:
  The lighter scalar tau lepton $\sti$ may be the lightest scalar lepton and
therefore would be found earlier in future collider experiments. We point out
the impact of the measurement of the mass and the mixing angle of $\st$ to
discriminate the models of SUSY breaking. Furthermore, the measurement of the
polarization of $\tau$ lepton($P_{\tau}$) from the decaying $\sti$ helps to
determine the Yukawa sector of minimal supersymmetric standard model. We
present our MC study of the production and the decay of $\sti$ lepton at a
future linear collider at $\sqrt{s}=500$ GeV. The mass, mixing angle of $\sti$
and $P_{\tau}(\sti\rightarrow\tau \chi_1^0)$ would be measured precisely at the
future LC. ( talks given at Yukawa International Seminar(YIKS) '95 on some very
hot and humid day in August, and also at Workshop on {\it Physics and
Experiments with Linear $e^+e^-$ Colliders} Appi, Iwate Japan Sep.8-12 1995.)


title: Dynamical Mass Generation in QED3 with Chern--Simons Term

abstract:
  In (2+1)-dimensional QED with a Chern-Simons term, we study dynamical
breaking of chiral symmetry, using the Dyson--Schwinger equation for the
fermions. There is a region in parameter space were dynamical chiral symmetry
breaking occurs, just as in pure QED3 (without Chern--Simons term); outside
this region, this chiral symmetry breaking solution does not exists. Our
results, both numerically and analytically, show that the chiral phase
transition is a discontinuous first-order transition.


title: Higgs potential bounds on extra quark-lepton generations

abstract:
  We consider the bounds for the values of higgs mass $M_H$ and of the mass of
the extra quarks and leptons $M_{extra}$ derived from the stability of vacuum
and from the absence of Landau pole in Higgs potential. We find that in the
case of the absence of new physics up to the GUT scale the bounds for the mass
of the 4th generation are so restrictive that the negative result of CDF search
for extra quarks closes the window for fourth generation. In the case of the
absence of new physics up to $10^5$ GeV we get weaker but still nontrivial
bounds on $M_H$ and $M_{extra}$ as well.


title: The $\Delta I = 1/2$ Selection Rule

abstract:
  We compute the isospin $I= 0$ and 2 amplitudes for the decay of a kaon into
two pions by estimating the relevant hadronic matrix elements in the chiral
quark model. The results are parametrized in terms of the quark and gluon
condensates and of the constituent quark mass $M$. The latter is a parameter
characteristic of the model, that we restrict by matching the results in the
two $\gamma_5$-schemes (HV and NDR) of dimensional regularization. We find
that, for values of these parameters within the current determinations, the
$\Delta I= 1/2$ selection rule is well reproduced by means of the cumulative
effects of short-distance NLO Wilson coefficients, penguin diagrams,
non-factorizable soft-gluon corrections and meson-loop renormalization.


title: Two- and Three-Body Decay Modes of SUSY Higgs Particles

abstract:
  We summarize the dominant decay modes of the neutral and charged Higgs bosons
in the Minimal Supersymmetric extension of the Standard Model. While two--body
decays are in general dominating, the branching ratios for three--body decays
of the heavy scalar, pseudoscalar and charged Higgs bosons can be large below
the thresholds if top quarks, $W/Z$ bosons or heavy scalar bosons are involved.
Analytical expressions have been derived for the partial decay widths and the
physical implications of these decay modes are discussed.


title: Dicyclic Horizontal Symmetry and Supersymmetric Grand Unification

abstract:
  It is shown how to use as horizontal symmetry the dicyclic group $Q_6 \subset
SU(2)$ in a supersymmetric unification $SU(5)\otimes SU(5)\otimes SU(2)$ where
one $SU(5)$ acts on the first and second families, in a horizontal doublet, and
the other acts on the third. This can lead to acceptable quark masses and
mixings, with an economic choice of matter supermultiplets, and charged lepton
masses can be accommodated.


title: QCD Corrections to Hadronic Higgs Decays

abstract:
  We present an update of the branching ratios for Higgs decays in the Standard
Model and the Minimal Supersymmetric extension of the Standard Model. In
particular, the decays of the Higgs particles to quark and gluon jets are
analyzed and the spread in the theoretical predictions due to uncertainties of
the quark masses and the QCD coupling is discussed.


title: Polarized Structure Functions: a Theoretical Update

abstract:
  We review recent developments in the theory and phenomenology of polarized
structure functions. We summarize recent experimental data on the proton and
deuteron structure function $g_1$, and their impact on the understanding of
polarized sum rules. Specifically, we discuss how accurate measurements of the
singlet and nonsinglet first moment of $g_1$ test perturbative and
nonperturbative QCD, and critically examine the way these measurements are
arrived at. We then discuss how the extraction of structure functions from the
data can be improved by means of a theoretical analysis of their $x$ and $Q^2$
dependence, and how, conversely, experimental information on this dependence
can be used to pin down the polarized parton content of the nucleon.


title: QCD et les processus exclusifs durs (QCD and hard exclusive processes)

abstract: We review the theory of hard exclusive reactions in QCD.


title: Fermiophobic Higgs bosons at the Tevatron

abstract:
  Higgs bosons with negligible couplings to fermions can arise in various
non--minimal Higgs sectors. We show that such a particle could be discovered
during the current run at the Tevatron, and would be evidence against a minimal
supersymmetric Higgs sector.


title: Disoriented Chiral Condensate and Strong Electromagnetic Fields

abstract:
  We discuss the effect of strong electromagnetic fields on chiral orientation
in the framework of the linear $\sigma$ model. Based on lessons we learn from
computation of the effective potential at one loop, we argue that the chiral
U(1) anomaly dominates chiral disorientation driven by electromagnetism. We
show that the anomaly effect induces a quasi-instantaneous ``kick'' to field
configurations along the $\pi^0$ direction in relativistic heavy ion
collisions. We discuss the possibility that a ``kick'', even though small in
magnitude, can have a substantial effect on the formation of chirally
misaligned domains.


title: Dynamical Breaking of CPT Symmetry in Defect Networks and Baryogenesis

abstract:
  Based on a study of {\it charge,} (C), {\it parity} (P) and {\it time
reversal} (T) symmetries we show how a CP violating network of defects in the
early Universe may bias baryon number production. A static network, even though
it violates CP, respects CPT and hence does not bias baryon number production.
On the other hand, the {\it ordering dynamics\/} of defects in a network,
governed by the interplay of string tension, friction, inertia and the
expansion of the Universe, results in the dynamical breakdown of CPT symmetry
and may lead to a net baryon number production.


title: A Viable Model of Dynamical Supersymmetry Breaking in the Hidden Sector

abstract:
  We propose a simple and natural model of dynamical supersymmetry breaking,
which could be used as a mechanism for spontaneous supersymmetry breaking in a
gravitationally coupled hidden sector. The gaugino masses in the visible sector
are naturally of the same size as the squark, slepton, and gravitino masses.


title:
Contributions of below--threshold decays to ${\cal {MSSM}}$ Higgs
  branching ratios: Erratum

abstract:
  In Ref.~\cite{paper} we calculated 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.
Unfortunately, an error in one of the subroutines of the {\tt FORTRAN} code we
used was affecting the computation of the off--shell partial widths of the
decays $A\ar Z^{0*}h^*$ and $H^\pm\ar W^{\pm *}h^*$. This has now been fixed,
and the corrected plots are presented here


title: The CP Asymmetry in $b \to s l^+ l^-$ Decay

abstract:
  Using the experimental upper bound on the neutron EDM and experimental result
on $b\rightarrow s\gamma$ branching ratio we have calculated CP asymmetry and
$\Gamma^{2HDM}(b\rightarrow s{\it{l^{+}l^{-}}})/\Gamma^{SM}(b\rightarrow
s{\it{l^{+}l^{-}}})$. It is shown that in the invariant dilepton mass $q^{2}$
region $(m_{\psi'}^{2}+0.2\; GeV^{2})<\;q^{2}<\;m^{2}_{b}$ the CP asymmetry is
maximal and quite detectable.