title: The hard QCD Pomeron: some aspects of its phenomenology and interactions

abstract:
  The Regge limit in perturbative QCD for processes as DIS (low x) and photon
or onia-particles scattering is considered. In the first part a
phenomenological approach for the inclusion of the running coupling, preserving
the gluon reggeization property, is analyzed. In particular the spectrum of the
hard pomeron equation and the asymptotic form of the solution are used to study
scattering processes with also inclusive jet production. The singlet part of
the proton structure function is evolved towards the low x region according to
the full equation. In the second part the problem of unitarity in the QCD is
considered. Following the general Bartels approach the four reggeized gluon
system is studied in the large number of colours limit. The interplay between
double pomeron exchange and triple pomeron vertex contributions is studied. The
conformal invariance of the three pomeron vertex is shown in terms of a
building block function, and the coupling to pomerons has been considered to
make contact with the colour dipole picture which presents a similar triple
pomeron interaction. It is also shown that in the A.H. Mueller approach his
equation for higher order colour dipole densities leads to solutions which can
be represented as fan diagrams with only triple pomeron vertices. Finally we
draw some conclusion and open problems.


title: Domain Formation in Finite-Time Quenches

abstract:
  We study the formation of domains in a continuous phase transition with a
finite-temperature quench. The model treated is the $\Phi^4$ theory in two
spatial dimensions with global O(2) symmetry. We investigate this using
real-time thermal field theory, following Boyanovsky and collaborators, and
find that domain sizes appear to be smaller than those produced in an
instantaneous quench in the tree-level approximation. We also propose that a
more physical picture emerges by examining the two-point functions which do not
involve any cutoff on the short wavelength Goldstone modes.


title: Evidence for quantum chaos in the plasma phase of QCD

abstract:
  We investigate the eigenvalue spectrum of the staggered Dirac matrix in SU(3)
gauge theory and in full QCD on a $6^3\times 4$ lattice. As a measure of the
fluctuation properties of the eigenvalues, we study the nearest-neighbor
spacing distribution $P(s)$ for various values of $\beta$ both in the
confinement and in the deconfinement phase. In both phases except far into the
deconfinement region, the lattice data agree with the Wigner surmise of
random-matrix theory which is indicative of quantum chaos. We do not find signs
of a transition to Poisson regularity at the deconfinement phase transition.


title:
Interpolating between Soft and Hard Dynamics in Deep Inelastic
  Scattering

abstract:
  An explicit model for the proton structure function interpolating between
low- (VMD and Regge behavior)and high-$Q^2$ (GLAP evolution) is suggested. The
model is fitted to the experimental data in a wide range of the kinematical
variables with emphasis on the low-$x$ HERA data. The boundaries, transition
region and interface between various regimes are quantified.


title: Dynamical fragment production in central collisions Xe(50 A.MeV)+Sn

abstract:
  For central collisions Xe(50 A.MeV)+Sn we compared experimental data from the
INDRA detector with QMD simulations. Theory as well as experiment show a clear
binary character of the fragment emission even for very central collisions.
From the time evolution of the reaction (QMD simulation) we could built up a
scenario for the dynamical emission of fragments


title: Spin Dependent Structure Function $g_1$ at Low $x$

abstract:
  Theoretical expectations concerning small $x$ behaviour of the spin dependent
structure function $g_1$ are summarised. This includes discussion of the Regge
pole model predictions and of the double $ln^2(1/x)$ effects implied by
perturbative QCD. The quantitative implementation of the latter is described
within the unified scheme incorporating both Altarelli-Parisi evolution and the
double $ln^2(1/x)$ resummation. The double $ln^2(1/x)$ effects are found to be
important in the region of $x$ which can possibly be probed at HERA.
Predictions for the polarized gluon distribution $\Delta G(x,Q^2)$ at low $x$
are also given.


title: Chiral Disorder in QCD

abstract:
  Using the Gell-Mann-Oakes-Renner (GOR) relation and semi-classical arguments,
we show that the bulk quark spectrum in QCD exhibits a variety of regimes
including the ergodic one described by random matrix theory. We analyze the
quark spectral form-factor in the diffusive and ballistic regime. We suggest
that a class of chiral transitions in QCD is possibly of the metal-insulator
type, with a universal spectral statistics at the mobility edge.


title: Supersymmetry-Breaking Loops from Analytic Continuation into Superspace

abstract:
  We extend to all orders in perturbation theory a method to calculate
supersymmetry-breaking effects by analytic continuation of the renormalization
group into superspace. A central observation is that the renormalized gauge
coupling can be extended to a real vector superfield, thereby including soft
breaking effects in the gauge sector. We explain the relation between this
vector superfield coupling and the "holomorphic" gauge coupling, which is a
chiral superfield running only at 1 loop. We consider these issues for a number
of regulators, including dimensional reduction. With this method, the
renormalization group equations for soft supersymmetry breaking terms are
directly related to supersymmetric beta functions and anomalous dimensions to
all orders in perturbation theory. However, the real power of the formalism
lies in computing finite soft breaking effects corresponding to high-loop
component calculations. We prove that the gaugino mass in gauge-mediated
supersymmetry breaking is ``screened'' from strong interactions in the
messenger sector. We present the complete next-to-leading calculation of
gaugino masses (2 loops) and sfermion masses (3 loops) in minimal gauge
mediation, and several other calculations of phenomenological relevance.


title: Phase Transitions in the Universe

abstract:
  During the past two decades, cosmologists turned to particle physics in order
to explore the physics of the very early Universe. The main link between the
physics of the smallest and largest structures in the Universe is the idea of
spontaneous symmetry breaking, familiar from condensed matter physics.
Implementing this mechanism into cosmology leads to the interesting possibility
that phase transitions related to the breaking of symmetries in high energy
particle physics took place during the early history of the Universe. These
cosmological phase transitions may help us understand many of the challenges
faced by the standard hot Big Bang model of cosmology, while offering a unique
window into the very early Universe and the physics of high energy particle
interactions.


title: Nature of the scalar $a_0(980)$ and $f_0(980)$-mesons

abstract:
  It is presented a critical consideration of all unusual properties of the
scalar $a_0(980)$ and $f_0(980)$-mesons in the four-quark, two-quark and
molecular models. The arguments are adduced that the four-quark model is more
preferable. It is discussed the complex of experiments that could finally
resolve this issue.


title:
Isocurvature Fluctuations of the M-theory Axion in a Hybrid Inflation
  Model

abstract:
  The M-theory, the strong-coupling heterotic string theory, presents various
interesting new phenomenologies. The M-theory bulk axion is one of these. The
decay constant in this context is estimated as $F_a\simeq 10^{16}$ GeV. Direct
searches for the M-theory axion seem impossible because of the large decay
constant. However, we point out that large isocurvature fluctuations of the
M-theory axion are obtained in a hybrid inflation model, which will most likely
be detectable in future satellite experiments on anisotropies of cosmic
microwave background radiation.


title: Two-loop calculations in the MSSM

abstract:
  Recent results on two--loop calculations in the MSSM are reviewed. The
computation of the QCD corrections to \Delta\rho, \Delta r and to the mass of
the lightest Higgs boso in the MSSM are presented.


title: Effects of galactic dark halo rotation on WIMP direct detection

abstract:
  The effects of a possible rotation of the galactic dark halo on the
calculation of the direct detection rates for particle dark matter are
analyzed, with special attention to the extraction of the upper limits on the
WIMP--nucleon scalar cross section from the experimental data. We employ a
model of dark halo rotation which describes the maximal possible effects. For
WIMP masses above 50 GeV, the upper limit exclusion plot is modified by less
than a factor of two when rotation is included. For lighter masses the effect
can be stronger, suggesting the necessity to develop specific models of halo
rotation in order to provide more accurate conclusions.


title: The Donnachie-Landshoff pomeron and gauge invariance

abstract:
  The pomeron model of Donnachie and Landshoff does not conserve the
electromagnetic current when applied to diffractive reactions such as
electroproduction of a quark-antiquark pair or of a vector meson. We propose a
treatment of this problem which ensures a physical behaviour of cross sections
in the photoproduction limit and show that it leads to results rather similar
to those obtained from two-gluon exchange.


title: CP-Odd Tadpole Renormalization of Higgs Scalar-Pseudoscalar Mixing

abstract:
  We consider an Abelian model with a CP-conserving Higgs potential spanned by
two complex Higgs fields. The CP invariance of the Higgs potential is then
broken explicitly beyond the Born approximation by introducing
soft-CP-violating Yukawa interactions. Based on the non-renormalization
theorem, we derive the consistency conditions under which a CP-odd counterterm
exists and, at the same time, renders the one-loop-induced mixing of a CP-even
Higgs boson with a CP-odd Higgs scalar ultra-violet finite. The novel CP-odd
tadpole renormalization may then be determined from the minimization
constraints on the Higgs potential. Finally, we discuss the phenomenological
consequences of the so-generated CP-violating scalar-pseudoscalar mixing for
the electric dipole moments of neutron, electron and muon.


title:
The $\rho$-meson and related meson wave functions in QCD sum rules with
  nonlocal condensates

abstract:
  We apply the nonlocal condensate formalism to construct generalized sum rules
(including $O(\as)$-radiative corrections) for $\pi$-, $\rho$- and
$\rho'$-meson wave functions of twist 2. Besides, we predict the lepton decay
constant $f_{\rho'}$ and estimate the mass of $\rho'$-meson. For all these
mesons we obtain the first 10 moments of longitudinal wave functions, suggest
the models for them and discuss their properties. We consider the peculiarities
of the QCD sum rules with nonlocal condensates for transverse $\rho$- and
$b_1$-meson wave functions. These results are compared with those found by Ball
and Braun and by Chernyak and Zhitnitsky.


title: A four-neutrino mixing scheme for observed neutrino data

abstract:
  It has been observed that simultaneous explanation of the solar and
atmospheric neutrino deficits and the reported evidence for $\nu_{\mu}\to
\nu_{e}$ oscillation from the Los Alamos Liquid Scintillator Detector (LSND)
requires at least one extra neutrino species in addition to the three known
ones. The extra neutrino must be sterile with respect to the known weak
interactions. We present a new mass matrix for these four neutrinos in which
the LSND effect and the atmospheric neutrino deficit are governed by only one
parameter. We investigate the phenomenological implications of such a mass
matrix ansatz and suggest possible ways to understand it in gauge theories.


title:
Self-consistent approximations in relativistic plasmas: Quasiparticle
  analysis of the thermodynamic properties

abstract:
  We generalize the concept of conserving, Phi-derivable, approximations to
relativistic field theories. Treating the interaction field as a dynamical
degree of freedom, we derive the thermodynamic potential in terms of fully
dressed propagators, an approach which allows us to resolve the entropy of a
relativistic plasma into contributions from its interacting elementary
excitations. We illustrate the derivation for a hot relativistic system
governed by electromagnetic interactions.


title: Anomalous Effective Lagrangian and Theta Dependence in QCD at Finite N_c

abstract:
  We generalize the large N_c Di Vecchia-Veneziano-Witten (VVW) effective
chiral Lagrangian to the case of finite N_c by constructing the anomalous
effective Lagrangian for QCD. The latter is similar to its SUSY counterpart,
and has a holomorphic structure. The VVW construction is then recovered, along
with 1/N_c corrections, after integrating out the heavy "glueball" fields. A
new mass formula for eta' meson in terms of QCD condensates is obtained. The
picture of theta dependence in QCD for finite N_c is more complicated than the
one predicted by the large N_c approach.


title:
A Study of Weak Mesonic Decays of $\Lambda_c$ and $\Xi_c$ Baryons on the
  Basis of HQET Results

abstract:
  We investigate two-body Cabibbo-angle enhanced weak decays of charmed baryons
into octet baryon and pseudoscalar meson in the current algebra framework with
inclusion of the factorization terms which are evaluated using the HQET guided
baryonic form factors. We obtain the branching ratios and asymmetry parameters
for various Cabibbo-enhanced decays of $\Lambda_c^+$, $\Xi_c^+$ and $\Xi_c^0$
baryons. Sensitivity of the flavor dependence of the spatial wavefunction
overlap on the branching ratios and asymmetry parameters is also investigated.


title: Cosmic Strings in Low Mass Higgs Cosmology

abstract:
  A class of grand unified theories with symmetry breaking scale of order
$10^{16} GeV$ have a Higgs particle with mass in the $TeV$ scale. The cosmology
of such theories is very different from usual. We study the cosmic strings
obtained in such theories. These strings are much fatter than usual and their
mass per unit length is reduced, resulting in a significant reduction in their
cosmological effects. We also study the temperature evolution of such models.


title:
Spin Effects in Neutralino Production in $e^+e^-$ Annihilation with
  polarized beams

abstract:
  We study the process e^+ e^- -> chi^0_1 chi^0_2 and the subsequent decay
chi^0_2 -> chi^0_1 l^{+} l^{-}$ with polarized beams, including the complete
spin correlations of chi^0_2$. We present numerical results for the lepton
energy and angular distributions, and for the distribution of the opening angle
between the leptons for sqrt{s}=500 GeV. The effects of spin correlations are
important in the lepton angular distribution, especially for gaugino-like
neutralinos. The opening angle distribution is particularly suitable for
distinguishing between higgsino- and gaugino-like neutralinos. The polarized
cross sections and lepton angular distributions are very sensitive to the
mixing of the neutralinos.


title: Z-induced FCNCs and their effects on Neutrino Oscillations

abstract:
  Adding singlet neutrinos to the standard model spectrum in general gives rise
to Z-induced flavor-changing neutral currents. We study the impact of these
currents on matter-induced neutrino oscillations in the sun and in supernovae.
While the effects for solar neutrinos are negligible, dramatic effects are
possible for supernova neutrinos.


title:
Further numerical results on non-factorizable corrections to e+e- -->
  4fermions

abstract:
  Numerical results on non-factorizable corrections to e+e- --> WW -->
4fermions with semi-leptonic and hadronic final states, as well as to e+e- -->
ZZ --> 4fermions, are presented. The corrections turn out to be small in
comparison to the experimental uncertainty of LEP2, but they might compete with
the expected accuracy at future e+e--colliders.


title: Wick-Cutkosky model: an introduction

abstract:
  A general pedagogical survey of the basics of the Bethe-Salpeter equation and
in particular Wick-Cutkosky model is given in great technical details.


title: Hierarchies of R-violating interactions from Family Symmetries

abstract:
  We investigate the possibility of constructing models of R-violating LQD
Yukawa couplings using a single U(1) flavour-symmetry group and supermultiplet
charge assignments that are compatible with the known hierarchies of quark and
lepton masses. The mismatch of mass and current eigenstates inferred from the
known charged-current mixing induces the propagation of strong phenomenological
constraints on some R-violating couplings to many others. Applying these
constraints, we look for flavour-symmetry models that are consistent with
different squark-production hypotheses devised to explain the possible HERA
large-Q^2 anomaly. The e^+ d -> stop interpretation of the HERA data is
accommodated relatively easily, at the price of postulating an extra parity.
The e^+ s -> stop interpretation of the events requires models to have only
small (2,3) mixing in the down quark sector. The e^+ d -> scharm mechanism
cannot be accommodated without large violations of squark-mass universality,
due to the very strong experimental constraints on R-violating operators. We
display a model in which baryon decay due to dangerous dimension-five operators
is automatically suppressed.


title:
Discriminating MSW solutions to the solar neutrino problem with
  flux-independent information at SuperKamiokande and SNO

abstract:
  The two possible Mikheyev-Smirnov-Wolfenstein (MSW) solutions of the solar
neutrino problem (one at small and the other at large mixing angle), up to now
tested mainly through absolute neutrino flux measurements, require
flux-independent tests both for a decisive confirmation and for their
discrimination. To this end, we perform a joint analysis of various
flux-independent observables that can be measured at the SuperKamiokande and
Sudbury Neutrino Observatory (SNO) experiments. In particular, we analyze the
recent data collected at SuperKamiokande after 374 days of operation, work out
the corresponding predictions for SNO, and study the interplay between
SuperKamiokande and SNO observables. It is shown how, by using only
flux-independent observables from SuperKamiokande and SNO, one can discriminate
between the two MSW solutions and separate them from the no oscillation case.


title: Stabilized Singlets in Supergravity as a Source of the mu-parameter

abstract:
  Within the context of supergravity-coupled supersymmetry, fields which are
gauge and global singlets are usually considered anathema. Their vacuum
expectation values are shifted by quadratically divergent tadpole diagrams
which are cutoff at the Planck scale, destabilizing the classical potential and
driving the singlet field to large values. We demonstrate a new and generic
mechanism which stabilizes the singlet in the presence of an extended gauge
symmetry. Such a symmetry will be broken down to the Standard Model by the
supergravity interactions near the scale of spontaneous supersymmetry-breaking
in the hidden-sector (about 10^{10-11} GeV). The resulting singlet expectation
value is stabilized and naturally of order the gravitino mass, providing
therefore a weak-scale mass for the Higgs fields of the supersymmetric Standard
Model (a "mu-parameter"). The resulting low-energy theory is the minimal
supersymmetric Standard Model, with all new fields decoupling at the
intermediate scale.


title: Generalized Heavy Baryon Chiral Perturbation Theory

abstract:
  Standard SU(2) Heavy Baryon Chiral Perturbation Theory is extended in order
to include the case of small or even vanishing quark condensate. The effective
lagrangian is given to ${\cal O}(p^2)$ in its most general form and to ${\cal
O}(p^3)$ in the scalar sector. A method is developed to efficiently construct
the relativistic baryonic effective lagrangian for chiral SU(2) to all orders
in the chiral expansion. As a first application, mass- and wave-function
renormalization as well as the scalar form factor of the nucleon is calculated
to ${\cal O}(p^3)$. The result is compared to a dispersive analysis of the
nucleon scalar form factor adopted to the case of a small quark condensate. In
this latter analysis, the shift of the scalar form factor between the
Cheng-Dashen point and zero momentum transfer is found to be enhanced over the
result assuming strong quark condensation by up to a factor of two, with
substantial deviations starting to be visible for $r=m_s/\hat{m}\lesssim 12$.


title: Improving the convergence of SU(3) baryon chiral perturbation theory

abstract:
  Baryon chiral perturbation theory as conventionally applied using dimensional
regularization has a well-known problem with the convergence of the SU(3)
chiral expansion. One can reformulate the theory equally rigorously using a
momentum-space cutoff and we show that the convergence is thereby greatly
improved for reasonable values of the cutoff. In effect, this is accomplished
because the cutoff formalism removes the spurious physics of propagation at
distance scales much smaller than the baryon size.


title:
Leptonic contribution to the effective electromagnetic coupling constant
  up to three loops

abstract:
  In this note the leptonic contribution to the running of the electromagnetic
coupling constant is discussed up to the three-loop level. Special emphasize is
put on the evaluation of the double-bubble diagrams.


title:
Inclusive Decay Rate for $B \to X_d + \gamma$ in Next-to-Leading
  Logarithmic Order and CP Asymmetry in the Standard Model

abstract:
  We compute the decay rate for the CKM-suppressed electromagnetic penguin
decay $B \to X_d + \gamma$ (and its charge conjugate) in NLO QCD, including
leading power corrections in $1/m_b^2$ and $1/m_c^2$ in the standard model. The
average branching ratio of the decay $B \to X_d\gamma$ and its charge conjugate
is estimated to be in the range $6.0 \times 10^{-6} \leq <BR(B \to X_d \gamma)>
\leq 2.6 \times 10^{-5}$, obtained by varying the CKM-Wolfenstein parameters
$\rho$ and $\eta$ in the range $-0.1 \leq \rho \leq 0.4$ and $0.2 \leq \eta
\leq 0.46$ and taking into account other parametric dependence. In the stated
range of the CKM parameters, we find the ratio $R(d\gamma/s\gamma) = <BR(B \to
X_d\gamma)>/<BR(B \to X_s\gamma)>$ to lie in the range between 0.017 and 0.074.
Theoretical uncertainties in this ratio are found to be small. Hence, this
ratio is well suited to provide independent constraints on the CKM parameters.
The CP-asymmetry in the $B \to X_d \gamma$ decay rates is found to be in the
range $(7 - 35)%$. Both the decay rates and CP asymmetry are measurable in
forthcoming experiments at $B$ factories and possibly at HERA-B.


title: The Hierarchy Problem and New Dimensions at a Millimeter

abstract:
  We propose a new framework for solving the hierarchy problem which does not
rely on either supersymmetry or technicolor. In this framework, the
gravitational and gauge interactions become united at the weak scale, which we
take as the only fundamental short distance scale in nature. The observed
weakness of gravity on distances $\gsim$ 1 mm is due to the existence of $n
\geq 2$ new compact spatial dimensions large compared to the weak scale. The
Planck scale $M_{Pl} \sim G_N^{-1/2}$ is not a fundamental scale; its enormity
is simply a consequence of the large size of the new dimensions. While
gravitons can freely propagate in the new dimensions, at sub-weak energies the
Standard Model (SM) fields must be localized to a 4-dimensional manifold of
weak scale "thickness" in the extra dimensions. This picture leads to a number
of striking signals for accelerator and laboratory experiments. For the case of
$n=2$ new dimensions, planned sub-millimeter measurements of gravity may
observe the transition from $1/r^2 \to 1/r^4$ Newtonian gravitation. For any
number of new dimensions, the LHC and NLC could observe strong quantum
gravitational interactions. Furthermore, SM particles can be kicked off our 4
dimensional manifold into the new dimensions, carrying away energy, and leading
to an abrupt decrease in events with high transverse momentum $p_T \gsim$ TeV.
For certain compact manifolds, such particles will keep circling in the extra
dimensions, periodically returning, colliding with and depositing energy to our
four dimensional vacuum with frequencies of $ \sim 10^{12}$ Hz or larger. As a
concrete illustration, we construct a model with SM fields localised on the
4-dimensional throat of a vortex in 6 dimensions, with a Pati-Salam gauge
symmetry $SU(4) \times SU(2) \times SU(2)$ in the bulk.


title:
Nonforward parton densities and soft mechanism for form factors and
  wide-angle Compton scattering in QCD

abstract:
  We argue that at moderately large momentum transfer -t <10 GeV^2, hadronic
form factors and wide-angle Compton scattering amplitudes are dominated by
mechanism corresponding to overlap of soft wave functions. We show that the
soft contribution in both cases can be described in terms of the same universal
nonforward parton densities (ND's) F(x;t), which are the simplest hybrids of
the usual parton densities and hadronic form factors. We propose a simple model
for ND's possessing required reduction properties. Our model easily reproduces
the observed magnitude and the dipole t-dependence of the proton form factor
F_1^p(t) in the region 1 GeV^2 < -t < 10 GeV^2. Our results for the wide-angle
Compton scattering cross section follow the angular dependence of existing data
and are rather close to the data in magnitude.


title:
Semileptonic decays, magnetic moments and spin distributions of spin-1/2
  baryons with sea contribution

abstract:
  Spin-1/2 baryons are considered as a composite system made out of a "core" of
three quarks surrounded by a "sea" (of gluons and $q\bar{q}$-pairs) which is
specified by its total quantum numbers. Specifically, we assume this sea to be
a flavor octet with spin-0 or 1 but no color. We show our model can provide
very goods fits to magnetic moments and semileptonic decay data using
experimental errors. The predictions for spin distributions are in reasonable
agreement with experiment.


title: Kaon and Muon Decay Phenomenology

abstract:
  Theoretical aspects of kaon and muon decays are reviewed. In particular,
three topics on kaon and muon decays, namely $K \to \pi\nu \bar{\nu}$
processes, T violation in $K^+ \to \pi^0\mu^+ \nu$ decay and lepton flavor
violation in muon decay are considered. Theoretical backgrounds and possible
significance on new physics searches by these processes are discussed.


title: Supersymmetry at Linear Colliders: The Importance of Being e-e-

abstract:
  Advantages of the e-e- option at linear colliders for the study of
supersymmetry are highlighted. The fermion number violating process $e^- e^-
\to \selectron^- \selectron^-$ provides unique opportunities for studies of
slepton masses and flavor mixings. In particular, slepton mass measurements at
the 100 MeV level through threshold scans of scalar pair production may be
possible. Such measurements are over an order of magnitude better than those
possible in e+e- mode, require far less integrated luminosity, and may lead to
precise, model-independent measurements of $\tan\beta$. Implications for
studying gauginos and the importance of accurate beam polarimetry are also
discussed.


title: Lepton Flavour Violation in Unified Models with U(1)-Family Symmetries

abstract:
  Lepton flavour non-conserving processes are examined in the context of
unified models with U(1)-family symmetries which reproduce successfully the
low-energy hierarchy of the fermion mass spectrum and the Kobayashi - Maskawa
mixing. These models usually imply mixing effects in the supersymmetric scalar
sector. We construct the fermion and scalar mass matrices in two viable models,
and calculate the mixing effects on the $\mu \to e\gamma$, $\mu \to 3 e$ and
$\tau \to \mu\gamma$ rare decays. The relevant constraints on the sparticle
mass spectrum as well as the role of various MSSM parameters are discussed.


title:
Current constraints on squark production scenarios for the excess of
  high $Q^2$ events at HERA

abstract:
  We examine the stop production scenario for the anomalous excess of high
$Q^2$ events observed at HERA, by taking into account the constraints coming
from the leptoquark search at Tevatron and the atomic parity violation
experiments. This scenario is shown to survive persistently even under the
severe constraints from the other experiments. In the analysis, the branching
ratios $B_{\stp_j}$ of the decay modes $\stp_j\to ed$ $(j=1,2)$ are found to be
useful parameters, representing a number of unknown parameters in the SUSY
models. By expressing the stop contribution to the cross section of deep
inelastic $ep$ scattering $\sigma(ep\to eX)$ in terms of $B_{\stp_1}$ and
$B_{\stp_2}$, the allowed region is successfully identified in the parameter
space of $B_{\stp_1}$ and $B_{\stp_2}$.


title: The Cambridge Jet algorithm: features and applications

abstract:
  Jet clustering algorithms are widely used to analyse hadronic events in high
energy collisions. Recently a new clustering method, known as `Cambridge', has
been introduced. In this article we present an algorithm to determine the
transition values of y_cut for this clustering scheme, which allows to resolve
any event to a definite number of jets in the final state. We discuss some
particularities of the Cambridge clustering method and compare its performance
to the Durham clustering scheme for Monte Carlo generated e+e- annihilation
events.


title: Texture dynamics including potential sterile neutrino

abstract:
  A unified form of mass matrix proposed previously for all fundamental
fermions is extended to include the sterile neutrino $\nu_s$, presumed to mix
mainly with $\nu_e$, while $\nu_\tau$ mixes strongly with $\nu_\mu$ (and both
$\nu_\mu$ and $\nu_\tau$ weakly with $\nu_e$ and $\nu_s$). It turns out that
the former mixing can be responsible for oscillations of solar neutrinos, while
the latter for those of atmospheric neutrinos. It is mentioned in a footnote
that $\nu_s$ is one of two sterile neutrinos, possible from a viewpoint of an
algebraic construction. The charged-lepton factor $U^{(e)}$ in the leptonic
four-dimensional CKM matrix $V=U^{(\nu) \dagger}U^{(e)}$ is determined through
the small deviation of our previous prediction $m_\tau=1776.80$ MeV (valid at
the level of $ U^{(e)} = {\bf 1}$) from the experimental value
$m_\tau=1777.00^{+0.30}_{-0.27}$ MeV. Then, it gives corrections to the
four-dimensional mixing of $\nu_e$, $\nu_\mu$, $\nu_\tau$, $\nu_s$ leading, in
particular, to small $\nu_e\to\nu_\mu$, $\nu_e\to \nu_\tau$ and
$\nu_\mu\to\nu_s$ oscillations (absent at the level of $U^{(e)}= 1$). However,
the LSND estimates of $\bar{\nu}_\mu \to \bar{\nu}_e$ and $\nu_\mu\to\nu_e$
oscillations are too large to be explained by these corrections, though in the
case of $\nu_\mu \to\nu_e$ they seem to be at the edge of such possible
explanation.


title: Fermiophobic and other non-minimal neutral Higgs bosons at the LHC

abstract:
  The phenomenology of neutral Higgs bosons from non--SUSY, extended Higgs
sectors is studied in the context of the LHC, with particular attention given
to the case of a fermiophobic Higgs. It is found that enhanced branching ratios
to $\gamma\gamma$ and $\tau^+\tau^-$ are possible and can provide clear
signatures, while detection of a fermiophobic Higgs will be problematic beyond
a mass of 130 GeV.


title: Leading Particle Effect in the $J/\Psi$ Elasticity Distribution

abstract:
  Recent DESY-HERA data on $J/\Psi$ elasticity distribution show that it
emerges mostly as a fast particle. Interpreting photoproduction as a collision
between a pre-formed charmed hadron and the proton, the outcoming $J/\Psi$ is a
leading particle of the collision. We analyse these data using a model
formulated to describe energy flow in hadron-hadron reactions. The measured
$J/\Psi$ spectrum can be successfully described in terms of this model. We
conclude that the observed transparency of the charmed hadron-proton collisions
arises because of the particularly small gluonic content of the initial $c -
\bar c$ state.


title: Physics with a Millimole of Muons

abstract:
  The eventual prospect of muon colliders reaching several TeV encourages us to
consider the experimental opportunities presented by very copious stores of
muons, approaching $10^{21}$ per year. I summarize and comment upon some
highlights of the Fermilab Workshop on Physics at the First Muon Collider and
at the Front End of a Muon Collider. Topics include various varieties of
$\mu\mu$ colliders, $\mu p$ colliders, and applications of the intense neutrino
beams that can be generated in muon storage rings.


title: On the energy dependence of hadronic $B_c$ production

abstract:
  An estimate is presented of the production cross section of $B_c$ mesons
between threshold and LHC energies using lowest-order perturbation theory and
non-relativistic bound state approximation. It is shown that the ratio of the
production cross sections for $B_c$ mesons and for $b$ quarks varies strongly
with energy.


title:
Hadronic Phases and Isospin Amplitudes in $D(B) \to \pi \pi$ and $D(B)
  \to K \bar K$ Decays

abstract:
  Hadronic phase in $\pi \pi$ and $K \bar K$ channels are calculated a la
Regge. At the D mass one finds $\delta_{\pi \pi} \approx \pi/3$ and $\delta_{K
\bar K} \approx -\pi/6$ in good agreement with the CLEO data while at the B
mass these angles are predicted to be, respectively, $11^\circ$ and $-7^\circ$.
With the hadronic phase $e^{i \delta_{K \bar K}}$ taken into account, a quark
diagram decomposition of the isospin invariant amplitudes in $D \to K \bar K$
decays fits the data provided the exchange diagram contribution is about 1/3 of
the tree level one.


title: Quark Distribution in Pion within Instanton Liquid Model

abstract:
  The leading-twist valence-quark distribution function in the pion is obtained
at a low normalization scale of an order of the inverse average size of an
instanton $\rho_c$. The momentum dependent quark mass and the quark-pion vertex
are constructed in the framework of the instanton liquid model, using a gauge
invariant approach. The parameters of instanton vacuum, the effective instanton
radius and quark mass, are related to the vacuum expectation values of the
lowest dimension quark-gluon operators and to the pion low energy observables.
An analytic expression for the quark distribution function in the pion for a
general vertex function is derived. The results are QCD evolved to higher
momentum-transfer values, and reasonable agreement with phenomenological
analyzes of the data on parton distributions for the pion is found.


title: Instantons in the Large Q^2, x Region at HERA

abstract:
  A new mechanism for an increased event production in the large $Q^2$, $x$
region at HERA is suggested. This mechanism results from a new type of
instanton-induced quark-quark interaction, which is related to non-zero quark
modes in the instanton field. We estimate the contribution of this interaction
to the valence quark structure function $F_2^v$ using the gas instanton model
approximation for the QCD vacuum. It is shown that this interaction can give a
large contribution to $F_2^v$, especially at large values of $Q^2$. The strong
dependence of this contribution on the quark masses and $Q^2$ is discussed, and
it is concluded that a large charm quark contribution to events at high $Q^2$
can result from charm pair creation in the instanton field. We also obtain a
sizeable contribution to the valence quark longitudinal structure function
$F_L^v$ at high $Q^2$. Experimental observables which can check this instanton
mechanism in the high $Q^2$ region at HERA are suggested.


title: Chiral predictions for K_L -> pi0 gamma mu+ mu-

abstract:
  We have previously analysed the chiral predictions for the decay K_L -> pi0
gamma e+ e- and discussed how experimental measurements of this process can
help our understanding of chiral theories and of CP tests. Motivated by the
possibility that the analogous muonic process may soon be measurable, we extend
this calculation to the decay K_L -> pi0 gamma mu+ mu-. Branching ratios and
differential branching ratios are calculated and presented. Measurements of
these will help shed some light on the puzzles in our understanding of the
chiral loop effects which were raised by the rate for K_L -> pi0 gamma gamma.


title: Chiral Dynamics of the low-energy Kaon-Baryon interactions

abstract:
  The processes involving $K^{-}p, KN, \Sigma\pi, \Lambda\pi,\Sigma\eta,
  \Lambda\eta$ coupled channels are studied in the nonperturbative chiral
approach.
  An effective potential is constructed using a chiral meson-baryon Lagrangian
at lowest order. This potential is iterated to all orders with the
Lippmann-Schwinger equation.
  A reasonable fit of the experimental data is obtained.
  It is pointed out, however, that due to a strong sensitivity of the results
to the value of the cut-off, such an approach should be viewed as a rather
phenomenological way to fit the experimental data since there is no small
expansion parameter allowing for truncation of the chiral expansion of the
effective potential at some given order. A possible way to construct the
consistent chiral expansion is briefly discussed


title: Natural Candidates for Superheavy Dark Matter in String and M Theory

abstract:
  We reconsider superheavy dark matter candidates in string and M theory, in
view of the possibility that inflation might generate superheavy particles with
an abundance close to that required for a near-critical Universe. We argue that
cryptons - stable or metastable bound states of matter in the hidden sector -
are favoured over other possible candidates in string or $M$ theory, such as
the Kaluza-Klein states associated with extra dimensions. We exhibit a specific
string model that predicts cryptons as hidden-sector bound states weighing
$\sim 10^{12}$ GeV, and discuss their astrophysical observability.


title:
Effective CP-violating operators of the tau lepton and some of their
  phenomenologies

abstract:
  The dimension-six CP-violating SU_L(2)\times U_Y(1) invariant operators
involving the tau lepton are studied. The constraints from the available
experimental data on tau dipole moments are derived. Under the current
constraints, the induced CP-violating effects could possibly be observed in tau
-> 3\pi \nu_{\tau} at the future tau-charm factory.


title:
Unification Picture in Minimal Supersymmetric SU(5) Model with String
  Remnants

abstract:
  The significant heavy threshold effect is found in the supersymmetric SU(5)
model with two adjoint scalars, one of which is interpreted as a massive string
mode decoupled from the lower-energy particle spectra. This threshold related
with the generic mass splitting of the basic adjoint moduli is shown to alter
properly the running of gauge couplings, thus giving a natural solution to the
string-scale grand unification as prescribed at low energies by LEP precision
measurements and minimal particle content. The further symmetry condition of
the (top-bottom) Yukawa and gauge coupling superunification at a string scale
results in the perfectly working predictions for the top and bottom quark
masses in the absence of any large supersymmetric threshold corrections.


title:
QCD Evolution Equations: Numerical Algorithms from the Laguerre
  Expansion

abstract:
  A complete numerical implementation, in both singlet and non-singlet sectors,
of a very elegant method to solve the QCD Evolution equations, due to Furmanski
and Petronzio, is presented. The algorithm is directly implemented in x-space
by a Laguerre expansion of the parton distributions. All the leading-twist
distributions are evolved: longitudinally polarized, transversely polarized and
unpolarized, to NLO accuracy. The expansion is optimal at finite x, up to
reasonably small x-values ($x\approx 10^{-3}$), below which the convergence of
the expansion slows down. The polarized evolution is smoother, due to the less
singular structure of the anomalous dimensions at small-x. In the region of
fast convergence, which covers most of the usual perturbative applications,
high numerical accuracy is achieved by expanding over a set of approximately 30
polynomials, with a very modest running time.


title: On the relation between QCD potentials in momentum and position space

abstract:
  We derive a formula which relates the QCD potentials in momentum space and in
position space in terms of the beta-function of the renormalization-group
equation for the potential. This formula is used to study the theoretical
uncertainties in the potential and in particular in its application to the
determination of the pole mass m_b when we use perturbative expansions. We
demonstrate the existence of these uncertainties for the Richardson potential
explicitly and then discuss the limited theoretical accuracy in the
perturbative QCD potential. We conclude that a theoretical uncertainty of m_b
much below 100 MeV would not be achievable within perturbative QCD.


title:
Hard QCD. Plenary talk at the Quark Matter -97 Conference, December
  1997, Tsukuba, Japan

abstract:
  Status of hard/perturbative QCD phenomena is briefly reviewed.
Landau-Pomeranchuk-Migdal effect is discussed as a means for establishing links
between particle and nuclear high-energy physics.


title: Radiative Breaking of Gauge Symmetries in the MSSM and in its Extensions

abstract:
  The radiative electroweak symmetry breaking, the b-\tau Yukawa and gauge
couplings unification in the MSSM and its SU(5) extensions are studied in
detail. In the framework of the two-loop renormalization group equations both
low- and high-energy threshold effects are included. In the case of the minimal
SU(5), the values of \alpha_s obtained are somewhat larger than the
experimental average. The Peccei-Quinn version of the missing-doublet SU(5)
model generally predicts smaller values of \alpha_s and b-\tau unification, in
excellent agreement with all low energy experimental data. We also study the
generation of the GUT scale through radiative corrections in the context of an
R-symmetric ``flipped" SU(5) x U(1)_X model and we find that this is possible
in a certain range of values of the parameter space.


title: Isospin Mass Splittings of Baryons in Potential Models

abstract:
  We discuss the isospin-breaking mass differences among baryons, with
particular attention in the charm sector to the $\Sigma_c^{+}-\Sigma_c^0$,
$\Sigma_c^{++}-\Sigma_c^0$, and $\Xi_c^+-\Xi_c^0$ splittings. Simple potential
models cannot accommodate the trend of the available data on charmed baryons.
More precise measurements would offer the possibility of testing how well
potential models describe the non-perturbative limit of QCD.


title:
QCD at Finite Baryon Density: Chiral Symmetry Restoration and Color
  Superconductivity

abstract:
  We use a variational procedure to study finite density QCD in an
approximation in which the interaction between quarks is modelled by that
induced by instantons. We find that uniform states with conventional chiral
symmetry breaking have negative pressure with respect to empty space at all but
the lowest densities, and are therefore unstable. This is a precisely defined
phenomenon which motivates the basic picture of hadrons assumed in the MIT bag
model, with nucleons as droplets of chiral symmetry restored phase. This
suggests that the phase transition to a chirally symmetric phase occurs by
percolation of preexisting droplets of the symmetric phase, and in these
proceedings we expand upon our previous presentation of this observation. At
all densities high enough that the chirally symmetric phase fills space, color
symmetry is broken by the formation of a <qq> condensate of quark Cooper pairs.
A plausible ordering scheme leads to a substantial gap in a Lorentz scalar
channel involving quarks of two colors.


title:
Renormalon Model Predictions for Power-Corrections to Flavour Singlet
  Deep Inelastic Structure Functions

abstract:
  We analyze power corrections to flavour singlet deep inelastic scattering
structure functions in the framework of the infrared renormalon model. Our
calculations, together with previous results for the non-singlet contribution,
allow to model the x-dependence of higher twist corrections to F_2, F_L and g_1
in the whole x domain.


title:
Lepton asymmetries in exclusive $b \to s\ell^+\ell^-$ decays as a test
  of the Standard Model

abstract:
  We argue that the longitudinal lepton polarization and the forward-backward
asymmetries in exclusive $B\to (K,K^*)\ell^+\ell^-$ decays are largely
unaffected by the theoretical uncertainties in the long-distance contributions
both induced by the long-range charming penguins in the $\ell^+\ell^-$ channel
and those in the meson channels encoded in the meson transition form factors,
and are mainly determined by the short-distance Wilson coefficients at the
low-energy scale $\mu\simeq m_b$. Thus, the above mentioned asymmetries provide
a powerful probe of the Standard Model and its extensions.


title:
Screening effects in Relativistic Models of Dense Matter at Finite
  Temperature

abstract:
  We investigate screening effects of the medium on the potential interaction
between two static 'charges' for different models of dense plasmas in the
one-boson exchange approximation. The potential can exhibit an oscillatory
behavior, which is related to the analytic structure of the corresponding boson
propagators in the complex $q$-plane. We have first revisited the one-pion
exchange in a nuclear medium. In addition to Friedel oscillations, which are
associated to branch cuts in the $q$-plane, there appears another oscillatory
component, which arises from a pole on the pion propagator. This pole is
located appart from the axes, giving rise to an oscillating Yukawa-like
potential. Therefore, we call this phenomenon 'Yukawa oscillations'. This
phenomenon does not appear in the Debye component of the QED screened
potential, even if the coupling constant is artificially increased. We have
also studied a model of QCD quark-gluon plasma. In this case, the one-gluon
propagator also shows this kind of poles. At high densities and/or
temperatures, where one expects perturbative QCD to be valid, the pole shifts
towards large momenta.


title:
Can Momentum Correlations Proof Kinetic Equilibration in Heavy Ion
  Collisions at 160 AGeV?

abstract:
  We perform an event-by-event analysis of the transverse momentum distribution
of final state particles in central Pb(160AGeV)+Pb collisions within a
microscopic non-equilibrium transport model (UrQMD). Strong influence of
rescattering is found. The extracted momentum distributions show less
fluctuations in A+A collisions than in p+p reactions. This is in contrast to
simplified p+p extrapolations and random walk models.


title: The Origin of Transverse Flow at the SPS

abstract:
  We study the transverse expansion in central Pb+Pb collisions at the CERN
SPS. Strong collective motion of hadrons can be created. This flow is mainly
due to meson baryon rescattering. It allows to study the angular distribution
of intermediate mass meson baryon interactions.


title: Low-Energy Compton Scattering of Polarized Photons on Polarized Nucleons

abstract:
  The general structure of the cross section of $\gamma N$ scattering with
polarized photon and/or nucleon in initial and/or final state is systematically
described and exposed through invariant amplitudes. A low-energy expansion of
the cross section up to and including terms of order $\omega^4$ is given which
involves ten structure parameters of the nucleon (dipole, quadrupole,
dispersion, and spin polarizabilities). Their physical meaning is discussed in
detail. Using fixed-t dispersion relations, predictions for these parameters
are obtained and compared with results of chiral perturbation theory. It is
emphasized that Compton scattering experiments at large angles can fix the most
uncertain of these structure parameters. Predictions for the cross section and
double-polarization asymmetries are given and the convergence of the expansion
is investigated. The feasibility of the experimental determination of some of
the struture parameters is discussed.


title: Lepto-mesons, Leptoquarkonium and the QCD Potential

abstract:
  We consider bound states of heavy leptoquark-antiquark pairs (lepto-mesons)
as well as leptoquark-antileptoquark pairs (leptoquarkonium). Unlike the
situation for top quarks, leptoquarks (if they exist) may live long enough for
these hadrons to form. We study the spectra and decay widths of these states in
the context of a nonrelativistic potential model which matches the recently
calculated two-loop QCD potential at short distances to a successful
phenomenological quarkonium potential at intermediate distances. We also
compute the expected number of events for these states at future colliders.


title: Large-N_c Baryons

abstract:
  A spin-flavor symmetry emerges for baryons in the large-N_c limit. Large-N_c
baryons form irreducible representations of the spin-flavor algebra, and their
static properties can be computed in a systematic expansion in 1/N_c. Symmetry
relations for static baryon matrix elements are obtained at various orders in
the 1/N_c expansion by neglecting subleading 1/N_c corrections. Equivalent
relations arise in the quark and Skyrme models, which satisfy the same
large-N_c group theory as QCD. The 1/N_c expansion yields useful results for
QCD baryons with N_c=3.


title:
Analytically expanded and integrated results for massive fermion
  production in two-photon collisions and a high precision alpha_s
  determination

abstract:
  The cross section for massive fermion production in two-photon collisions was
examined at next-to-leading order in QCD/QED for general photon helicity. The
delta function (virtual+soft) part of the differential cross section was
analytically integrated over the final state phase space. Series expansions for
the complete differential and total cross sections were given up to tenth order
in the parameter beta. These were shown to be of practical use and revealed
much structure. Accurate parametrizations of the total cross sections were
given, valid up to higher energies. The above results were applied to top quark
production in the region not too far above threshold. The cross section was
shown to be quite sensitive to alpha_s in the appropriate energy region.


title: x-Dependent Polarized Parton Distributions

abstract:
  Using QCD motivated and phenomenological considerations, we construct x-
dependent polarized parton distributions, which evolve under GLAP evolution,
satisfy DIS data and are within positivity constraints. Each flavor is done
separately and the overall set can be used to predict polarization asymmetries
for various processes. We perform our NLO analysis strictly in x space,
avoiding difficulties in moment inversion. Small-x results and other physical
considerations are discussed.


title:
The Balmer-Like Formula for Mass Distribution of Elementary Particle
  Resonances

abstract:
  Elementary particle resonances have been systematically analysed using all
available experimental data. We have come to the conclusion that the resonance
decay prodact momenta and masses of resonances are to be quantized. The Balmer-
like formula for masses of elementary particle resonances was obtained. These
observations allow us to formulate a strategy of experimental searches for new
resonances and systematize the known one.


title: Search for New Physics Through $e^- e^+ \to t \bar t$

abstract:
  If all new particles are too heavy to be directly produced in the future
Colliders, then the long sought New Physics (NP) could only appear in the form
of new interactions, beyond those of the Standard Model (SM). Many of the
processes that could be used to study these interactions, have already been
discussed in the literature. Here, I first briefly discuss the list of all not
yet excluded CP conserving such interactions, realized as $SU(3)\times SU(2)
\times U(1)$ gauge invariant $dim=6$ operators affecting the Higgs and the
quarks of the third family.
  Subsequently, I concentrate on the $\gamma t\bar t$ and $Zt\bar t$ vertices
generated by NP, and on the possibility to study them by using various spin
asymmetries accessible in $e^-e^+ \to t \bar t$, for polarized and unpolarized
beams. It is found that these asymmetries can fully determine the form of the
$\gamma t\bar t$ and $Zt\bar t$ couplings.


title: Up-Down Unification just above the supersymmetric threshold

abstract:
  Large corrections to the quark mass matrices at the supersymmetric threshold
allow the theory to have identical Yukawa matrices in the superpotential. We
demonstrate that Up-Down unification can take place in a moderate quark-squark
alignment scenario with an average squark mass of the order 1 TeV and with
$\tan\beta>15$


title: Core Phase Structure of Cosmic Strings and Monopoles

abstract:
  Global and local symmetries may or may not be restored inside topological
defects depending upon the values of the parameters of the model. A detailed
study of this parameter dependence of the core structure of strings and
monopoles is presented in the context of simple models.


title: On the Role of Charm in Decay of B-mesons to \eta ' K

abstract:
  In this letter we focus on the calculation of $f_{\eta'}^{(c)},$ the
amplitude of the $ (c\bar{c}) \to (gluons) \to \eta^{'}$ transition, which
provides the magnitude of the contribution of the Cabbibo favored $b \to \bar c
c s$ elementary process to $B \to \eta ' K$ decay. It is found that $f_{\eta
'}^{(c)} = - 12.3\sim -18.4 MeV$ on the scale of $m_{c}.$ This number is in
strong contradiction with the estimations of Halperin, Zhitnitsky and Shuryak,
Zhitnitsky but almost in agreement with phenomenological analysis of Feldman et
al.,
  Petrov and the estimations of Ali et al.


title: The More Relaxed Supersymmetric Electroweak Baryogenesis

abstract:
  We reanalyze the issue of generation of the baryon asymmetry at the
electroweak phase transition in the MSSM and compute the baryon asymmetry
assuming the presence of non-trivial CP-violating phases in the parameters
associated with the left-right stop mixing term and the Higgsino mass $\mu$.
Making use of the closed time-path (CTP) formalism of nonequilibrium field
theory, we write down a set of quantum Boltzmann equations describing the local
number density asymmetries of the particles involved in supersymmetric
electroweak baryogenesis. CP-violating sources manifest ``memory'' effects
which are typical of the quantum transport theory and are not present in the
classical approach. Compared to previous estimates, these non-Markovian
features enhance the final baryon asymmetry by at least two orders of
magnitude. This means that a CP-violating phase $|\sin \phi_{\mu}|$ as small as
$10^{-3}$ (or even smaller) is enough to generate the observed baryon
asymmetry.


title: Strongly-interacting Electroweak Sector At e-e- Colliders

abstract:
  We study the possible experimental signatures resulting from a
strongly-interacting electroweak sector at $e^-e^-$ colliders, emphasizing the
signal enhancement by high beam polarization. We also discuss the unique role
for operating the collider in $e^-\gamma$ mode to produce a heavy isosinglet
vector state $\omega_T$.


title: Modification of parton distributions in nuclei

abstract:
  Nuclear parton distributions are studied in a parton model with rescaling and
recombination mechanisms. Parton x distributions are first calculated at Q^2=1
GeV^2 by the model, and they are evolved to larger Q^2 in order to be compared
with various F_2 data. The experimental shadowing is explained by the
parton-recombination effects. Then, the modification of sea-quark and gluon
distributions is investigated. We show x and Q^2 dependent results of the
ratios S_A/S_D and G_A/G_D. They indicate significant shadowing at small x and
large ratios in the medium-x region. Our theoretical results should be tested
by future experiments, for example, at RHIC (Relativistic Heavy Ion Collider).
Furthermore, our studies are important for finding a signature of the
quark-gluon plasma in heavy-ion reactions. We also indicate that nuclear
effects in the deuteron should be taken into account for finding the accurate
F_2 structure function of the neutron.


title: PQCD study of the $B_{SL}$ and $n_c$ controversy in inclusive $B$ decays

abstract:
  We calculate the semileptonic branching ratio and the charm counting of
inclusive $B$ meson decays using the perturbative QCD formalism. For the
nonleptonic decays, we employ the modified factorization theorem, in which
Wilson coefficients evolve with the characteristic scales of the decay modes.
It is found that the decay rate of the single-charm mode $b\to c{\bar u}d$ is
enhanced, and a lower $B_{SL}$ is obtained without increasing $n_c$. We predict
a larger $b\to c \tau \bar{\nu}$ branching ratio compared to that from the
conventional heavy-quark-effective-theory based operator product expansion. Our
result of the $B$ meson lifetime is also consistent with the data.


title:
Magnetic and axial vector form factors as probes of orbital angular
  momentum in the proton

abstract:
  We have recently examined the static properties of the baryon octet (magnetic
moments and axial vector coupling constants) in a generalized quark model in
which the angular momentum of a polarized nucleon is partly spin $\langle S_z
\rangle$ and partly orbital $\langle L_z \rangle$. The orbital momentum was
represented by the rotation of a flux-tube connecting the three constituent
quarks. The best fit is obtained with $\langle S_z \rangle = 0.08\pm 0.15$,
$\langle L_z \rangle = 0.42\pm 0.14$. We now consider the consequences of this
idea for the $q^2$-dependence of the magnetic and axial vector form factors. It
is found that the isovector magnetic form factor $G_M^{\mathrm{isovec}}(q^2)$
differs in shape from the axial form factor $F_A(q^2)$ by an amount that
depends on the spatial distribution of orbital angular momentum. The model of a
rigidly rotating flux-tube leads to a relation between the magnetic, axial
vector and matter radii, $\langle r^2 \rangle_{\mathrm{mag}} =
f_{\mathrm{spin}} \langle r^2 \rangle_{\mathrm{axial}} + \frac{5}{2}
f_{\mathrm{orb}} \langle r^2 \rangle_{\mathrm{matt}}$, where $f_{\mathrm{orb}}/
f_{\mathrm{spin}} = \frac{1}{3}\langle L_z \rangle / G_A$, $f_{\mathrm{spin}} +
f_{\mathrm{orb}} = 1$. The shape of $F_A(q^2)$ is found to be close to a dipole
with $M_A = 0.92\pm 0.06$ GeV.


title:
Seesaw Majoron Model of Neutrino Mass and Novel Signals in Higgs Boson
  Production at LEP

abstract:
  We perform a careful study of the neutral scalar sector of a model which
includes a singlet, a doublet, and a triplet scalar field under $SU(2)$. This
model is motivated by neutrino physics, since it is simply the most general
version of the seesaw model of neutrino mass generation through spontaneous
violation of lepton number. The neutral Higgs sector contains three CP-even and
one massive CP-odd Higgs boson $A$, in addition to the massless CP-odd majoron
$J$. The weakly interacting majoron remains massless if the breaking of lepton
number symmetry is purely spontaneous. We show that the massive CP-odd Higgs
boson may invisibly decay to three majorons, as well as to a CP-even Higgs $H$
boson plus a majoron. We consider the associated Higgs production $e^+e^- \to Z
\to H A$ followed by invisible decays $A \to JJJ$ and $H \to JJ$ and derive the
corresponding limits on masses and coupling that follow from LEP I precision
measurements of the invisible Z width. We also study a novel $b \bar{b}
b\bar{b}p\!\!\!/_T$ signal predicted by the model, analyse the background and
perform a Monte-Carlo simulation of the signal in order to illustrate the
limits on Higgs boson mass, couplings and branching ratios that follow from
that.


title:
Next-to-next-to-leading order vacuum polarization function of heavy
  quark near threshold and sum rules for $b \bar b$ system

abstract:
  A correlator of the vector current of a heavy quark is computed analytically
near threshold in the next-to-next-to-leading order in perturbative and
relativistic expansion that includes $\al_s^2$, $\al_sv$ and $v^2$ corrections
in the coupling constant and velocity of the heavy quark to the nonrelativistic
Coulomb approximation. Based on this result, the numerical values of the
$b$-quark pole mass and the strong coupling constant are determined from the
analysis of sum rules for the $\Upsilon$ system. The next-to-next-to-leading
corrections are found to be of order of next-to-leading ones.


title:
Scenario for Ultrarelativistic Nuclear Collisions: Space--Time Picture
  of Quantum Fluctuations and the Birth of QGP

abstract:
  We study the dynamics of quantum fluctuations which take place at the
earliest stage of high-energy processes and the conditions under which the data
from e-p deep-inelastic scattering may serve as an input for computing the
initial data for heavy-ion collisions at high energies. Our method is
essentially based on the space-time picture of these seemingly different
phenomena. We prove that the ultra-violet renormalization of the virtual loops
does not bring any scale into the problem. The scale appears only in connection
with the collinear cut-off in the evolution equations and is defined by the
physical properties of the final state. In heavy-ion collisions the basic
screening effect is due to the mass of the collective modes (plasmons) in the
dense non-equilibrium quark-gluon system, which is estimated. We avoid the
standard parton phenomenology and suggest a dedicated class of evolution
equations which describe the dynamics of quantum fluctuations in heavy-ion
collisions.


title: Oscillations of recoil particles against mixed states

abstract:
  Some consequences of the oscillations of neutral kaons and neutrinos are
discussed, in particular, the possibility of oscillations of particles
recoiling against kaons or neutrinos from the production process. We show that
there are no stationary oscillations of these recoil particles in any order,
and that the apparent long-wavelength oscillations, which might appear to
result when an earlier treatment of ours was taken to higher order, are
spurious. We show that the recoil particles may show a travelling interference
pattern. It may be possible to observe this pattern for $\Lambda$s produced in
a reaction, but there seems to be little hope of observing this for the case of
neutrinos from muon decay.


title: $B \to X_{s} \tau^{+} \tau^{-}$ in the flipped SU(5) model

abstract:
  We perform a detailed study of the inclusive branching ratio and the
forward-backward asymmetry of the rare B decay process $B \longrightarrow X_{s}
\tau^{+} \tau^{-}$ in the flipped SU(5) model, a predictive model which has
only two free parameters, plus the sign of the higgs mixing mass $\mu$, to
describe mass spectrum and mixings of about 30 sparticles. In contrast to other
works dealing with such a topic, our study has included the contributions of
the neutral higgs bosons through penguin diagrams to this process under the
context of supersymmetry. In some regions of the parameter space, due to the
substantial enhancement effects coming from supersymmetry, these contributions
become quite significant and could make the flavor change process $B
\longrightarrow X_{s} \tau^{+} \tau^{-}$ a microscope to probe the regions of
large tan$\beta$ and a window to gain an insight into new physics beyond the
standard model(SM).


title:
Thermodynamics of Gauge-Invariant U(1) Vortices from Lattice Monte Carlo
  Simulations

abstract:
  We study non-perturbatively and from first principles the thermodynamics of
vortices in 3d U(1) gauge+Higgs theory, or the Ginzburg-Landau model, which has
frequently been used as a model for cosmological topological defect formation.
We discretize the system and introduce a gauge-invariant definition of a vortex
passing through a loop on the lattice. We then study with Monte Carlo
simulations the total vortex density, extract the physically meaningful part
thereof, and demonstrate that it has a well-defined continuum limit. The total
vortex density behaves as a pseudo order parameter, having a discontinuity in
the regime of first order transitions and behaving continuously in the regime
of second order transitions. Finally, we discuss further gauge-invariant
observables to be measured.


title:
Direct CP Violation in B -> X_s gamma Decays as a Signature of New
  Physics

abstract:
  We argue that the observation of a sizable direct CP asymmetry A_{CP} in the
inclusive decays B -> X_s gamma would be a clean signal of New Physics. In the
Standard Model, A_{CP} can be calculated reliably and is found to be below 1%
in magnitude. In extensions of the Standard Model with new CP-violating
couplings, large CP asymmetries are possible without conflicting with the
experimental value of the branching ratio for the decays B -> X_s gamma. In
particular, large asymmetries arise naturally in models with enhanced
chromo-magnetic dipole operators. Some generic examples of such models are
explored and their implications for the semileptonic branching ratio and charm
yield in B decays discussed.


title: Probing Top-Quark Couplings at Lepton and Photon Colliders

abstract:
  The ability of high energy lepton and photon colliders to probe the gauge
couplings of the top-quark is summarized.


title: B Physics Beyond the Standard Model

abstract:
  The ability of present and future experiments to test the Standard Model in
the $B$ meson sector is described. We examine the loop effects of new
interactions in flavor changing neutral current $B$ decays and in $Z\to b\bar
b$, concentrating on supersymmetry and the left-right symmetric model as
specific examples of new physics scenarios. The procedure for performing a
global fit to the Wilson coefficients which describe $b\to s$ transitions is
outlined, and the results of such a fit from Monte Carlo generated data is
compared to the predictions of our two sample new physics scenarios. A fit to
the $Zb\bar b$ couplings from present data is also given.


title: Phase transition induced by a magnetic field

abstract:
  The magnetic catalysis of discrete chiral symmetry breaking in the 2+1
dimensional Nambu-Jona-Lasinio model is analyzed. A particular attention is
paid to a possible application of the effect in solid state physics. The
fermion contribution to the thermal conductivity as a function of the dynamical
mass (energy gap in the spectrum) is estimated and is shown to be suppressed
when a non-zero order parameter develops.


title: The Quantum Vlasov Equation and its Markov Limit

abstract:
  The adiabatic particle number in mean field theory obeys a quantum Vlasov
equation which is nonlocal in time. For weak, slowly varying electric fields
this particle number can be identified with the single particle distribution
function in phase space, and its time rate of change is the appropriate
effective source term for the Boltzmann-Vlasov equation. By analyzing the
evolution of the particle number we exhibit the time structure of the particle
creation process in a constant electric field, and derive the local form of the
source term due to pair creation. In order to capture the secular Schwinger
creation rate, the source term requires an asymptotic expansion which is
uniform in time, and whose longitudinal momentum dependence can be approximated
by a delta function only on long time scales. The local Vlasov source term
amounts to a kind of Markov limit of field theory, where information about
quantum phase correlations in the created pairs is ignored and a reversible
Hamiltonian evolution is replaced by an irreversible kinetic one. This
replacement has a precise counterpart in the density matrix description, where
it corresponds to disregarding the rapidly varying off-diagonal terms in the
adiabatic number basis and treating the more slowly varying diagonal elements
as the probabilities of creating pairs in a stochastic process. A numerical
comparison between the quantum and local kinetic approaches to the dynamical
backreaction problem shows remarkably good agreement, even in quite strong
electric fields, over a large range of times.


title:
Addendum to: Radiative corrections to the Dalitz plot of semileptonic
  decays of neutral baryons with light or charm quarks

abstract:
  We show that the radiative corrections containing terms up to order $\alpha q
/ \pi M_1$ for unpolarized semileptonic decays of baryons with positron
emission can be obtained by simply reversing the sign of the axial-vector form
factors in the corresponding final expressions of such decays with electron
emission. This rule is valid regardless of the final kinematical variables
chosen and of the particular Lorentz frame in which the final results are
required.


title: Energy Dissipation of Axionic Boson Stars in Magnetized Conducting Media

abstract:
  Axions are possible candidates of dark matter in the present Universe. They
have been argued to form axionic boson stars with small masses $\sim
10^{-12}M_{\odot}$. Since they possess oscillating electric fields in a
magnetic field, they dissipate their energies in magnetized conducting media.
We show that colliding with a magnetized white dwarf, the axionic boson stars
dissipate their energies and heat the white dwarf. Consequently the white dwarf
cooled sufficiently can emit detectable amount of radiations with the
collision. Using a recent evaluation of the population of the white dwarfs as
candidates of MACHOs, we estimate the event rate of the collisions and obtain a
result that the rate is large to be detectable.


title: Higher-order QED corrections to e+e- to nu bar nu gamma at LEP2

abstract:
  The process e+e- to nu barnu + gamma with a distinctive
``photon-plus-missing-energy'' signal can serve as an important tool to search
for new physics at LEP2. It can be exploited to measure the WW gamma coupling,
or to search for weakly interacting and invisible (s)particles. For meaningful
comparisons of experimental data with theoretical predictions, higher-order QED
corrections due to multiphoton emission must be taken into account. In the
present paper we explain how the WW gamma coupling has been incorporated into
the KORALZ Monte Carlo program, which can now be used for simulations of e+e-
to nu bar nu + gamma events with higher-order QED corrections. The strategy of
how to perform an experimental analysis in the presence of experimental cuts is
proposed. The question of systematic uncertainties is addressed and some
numerical results for the phenomenologically interesting case of anomalous WW
gamma couplings are also given.


title:
CPT transformation properties of the exact effective Hamiltonian for
  neutral kaon and similar complexes

abstract:
  CPT-symmetry properties of the exact effective Hamiltonian H(eff) governing
the time evolution in the K(0), K(O)-bar (neutral K mesons) subspace implied by
such properties of the total Hamiltonian of the system under consideration are
examined. We show that H(eff) can commute with CPT - operator only if H does
not commute with it. We also find that, in contradistinction to the standard
result of the Lee-Oehme-Yang (LOY) theory, Re.<K(0)|H(eff)|K(0)> =
Re.<K(0)-bar|H(eff)|K(0)-bar>, i.e., (<K(0)|H(eff)|K(0)> -
<K(0)-bar|H(eff)|K(0)-bar>) = 0, only if the total system does not preserve
CPT-symmetry. Using more accurate approximation than Weisskopf-Wigner
approximation, an estimation of the difference (<K(0)|H(eff)|K(0)> -
<K(0)-bar|H(eff)|K(0)-bar>) is found for CPT-invariant generalized
Fridrichs-Lee model.


title: Perturbative Contributions to Field Correlators in Gluodynamics

abstract:
  The cancellation of perturbative contributions to the string tension in
gluodynamics in the framework of vacuum field correlators method is shown at
the order $O(g^4)$ by explicit calculation. The general pattern of these
cancellations at all orders and relation with the renormalization properties of
the Wilson loop is discussed.


title:
Neutrino magnetic moments and low-energy solar neutrino-electron
  scattering experiments

abstract:
  The scattering of solar neutrinos on electrons is sensitive to the neutrino
magnetic moments through an interference of electromagnetic and weak amplitudes
in the cross section. We show that future low-energy solar neutrino experiments
with good angular resolution can be sensitive to the resulting azimuthal
asymmetries in event number and should provide useful information on
non-standard neutrino properties such as magnetic moments. We compare
asymmetries expected at HELLAZ (mainly pp neutrinos) with those at the
Kamiokande and Super-Kamiokande experiments (Boron neutrinos), both for the
case of Dirac and Majorana neutrinos and discuss the advantages of low
energies. Potentially interesting information on the solar magnetic fields may
be accessible.


title: Stripping Cross Sections in Collisions of Light Nuclei

abstract:
  By evaluating all the contributions of the intermediate states of the
multiple scattering theory diagrams, we compute the integrated stripping cross
sections of collisions among light nuclei. The resulting expressions have the
simple form of a combination of total inelastic cross sections of nuclear
reactions with projectile nuclei differing in the atomic mass number. We also
check the accuracy of some widely used relations in heavy ion collisions.


title: B-ball Baryogenesis and the Baryon to Dark Matter Ratio

abstract:
  We demonstrate that B-ball decay in the MSSM can naturally solve the puzzle
of why the densities of baryons and dark matter in the Universe are similar.
This requires that the B-balls survive thermalization and decay below the
freeze-out temperature of the neutralino LSP, typically 1-10GeV. It is shown
that this can happen if the baryon asymmetry originates from a squark
condensate along the d=6 u^{c}d^{c}d^{c} D-flat direction of the MSSM scalar
potential. For this to work the reheating temperature after inflation must be
no greater than 10^3-10^5 GeV.


title: Balmer-Like Series for Baryon Resonances

abstract:
  The pole positions of various baryon resonances have been found to reveal a
well pronounced clustering, the so-called H"ohler cluster. In a previous work,
the H"ohler clusters have been shown to be identical to Lorentz multiplets of
the type (1/2+l', 1/2+l')*[(1/2,0)+(0,1/2)] with l' integer. Here we show that
the cluster positions are well described by means of a Balmer-series like
recursive mass formula.


title:
Power Corrections to Fragmentation Functions in Non-Singlet Deep
  Inelastic Scattering

abstract:
  We investigate the power-suppressed corrections to the fragmentation
functions of the current jet in non-singlet deep inelastic lepton-hadron
scattering. The current jet is defined by selecting final-state particles in
the current hemisphere in the Breit frame of reference. Our method is based on
an analysis of one-loop Feynman graphs containing a massive gluon, which is
equivalent to the evaluation of leading infrared renormalon contributions. We
find that the leading corrections are proportional to $1/Q^2$, as in $e^+e^-$
annihilation, but their functional forms are different. We give quantitative
estimates based on the hypothesis of universal low-energy behaviour of the
strong coupling.


title: Mirror Families in Electro-weak Symmetry Breaking

abstract:
  We study symmetry breaking in a left-right symmetric extension of the
Standard Model with mirror fermions, one for each Standard-Model fermion. The
new particles assist a top-quark condensate in breaking electro-weak symmetry.
Half of the fermions acquire electro-weak-invariant masses at around 500 GeV
and would be probably accessible at future high-energy experiments like LHC or
NLC. The contributions to the S and T parameters are small and negative in
accordance with electro-weak precision data.


title:
QED Logarithms in the Electroweak Corrections to the Muon Anomalous
  Magnetic Moment

abstract:
  We employ an effective Lagrangian approach to derive the leading-logarithm
two-loop electroweak contributions to the muon anomalous magnetic moment, a_mu.
We show that these corrections can be obtained using known results on the
anomalous dimensions of composite operators. We confirm the result of Czarnecki
et al. for the bosonic part and present the complete sin^2 \theta_W dependence
of the fermionic contribution. The approach is then used to compute the
leading-logarithm three-loop electroweak contribution to a_mu. Finally we
derive, in a fairly model-independent way, the QED improvement of new-physics
contributions to a_mu and to the electric dipole moment (EDM) of the electron.
We find that the QED corrections reduce the effect of new physics at the
electroweak scale by 6% (for a_mu) and by 11% (for the electron EDM).


title: Right-Handed Currents in B Decay Revisited

abstract:
  We critically re-examine the case for and against a sizeable right-handed
component in the $b\to c$ charged current coupling with a strength $\xi$
relative to the conventional left-handed current. Using data from CLEO on the
decay $B\to D^*\ell \nu$, as well as our knowledge of $V_{cb}$ extracted from
both inclusive and exclusive processes, we are able to determine the presently
allowed parameter space for $\xi$ via HQET. We then identify several
observables which could be measured at $B$ factories to either strengthen these
constraints or otherwise observe right-handed currents. This parameter space
region is found to be consistent with the low degree of $\Lambda_b$
polarization as determined by ALEPH as well as the measurements of the charged
lepton and neutrino energy spectra from $b$ decay made by L3. We discuss how
future measurements of semileptonic decay distributions may distinguish between
exotic $\Lambda_b$ depolarization mechanisms and the existence of right-handed
currents. Within the parameter space allowed by CLEO, using the Left-Right
Symmetric Model as a guide, we perform a detailed search for specific
sub-regions which can lead to a reduction in both the $B$ semileptonic
branching fraction as well as the the average yield of charmed quarks in $B$
decay. The results provide a concrete realization of an earlier suggestion by
Voloshin but may lead to potential difficulties with certain penguin mediated
decay processes.


title: On the QCD Phase Transition at Finite Baryon Density

abstract:
  We investigate the QCD chiral phase transition at finite chemical potential
$\mu$, using the renormalization group (RG) to characterize the infrared
behavior of sigma models constrained by the flavor and spacetime symmetries.
The results are similar to those obtained from RG analysis of the finite
temperature transition at zero baryon density. When there are more than two
massless flavors of quarks, a first order transition is predicted for the
entire phase boundary. In the two flavor case, a boundary with first and second
order regions separated by a tricritical point seems most likely. We discuss
the real-world case with two light quarks and an intermediate mass strange
quark. Improved lattice data on the temperature transition will strongly
constrain the possibilities for the phase boundary.


title: Massive Lepton Pairs as a Prompt Photon Surrogate

abstract:
  We discuss the transverse momentum distribution for the production of massive
lepton-pairs in hadron reactions at fixed target and collider energies within
the context of next-to-leading order perturbative quantum chromodynamics. For
values of the transverse momentum $Q_T$ greater than the pair mass $Q$, $Q_T >
Q$, we show that the differential cross section is dominated by subprocesses
initiated by incident gluons. Massive lepton-pair differential cross sections
are an advantageous source of constraints on the gluon density, free from the
experimental and theoretical complications of photon isolation that beset
studies of prompt photon production. We compare calculations with data and
provide predictions for the differential cross section as a function of $Q_T$
in proton-antiproton reactions at center-of-mass energies of 1.8 TeV, and in
proton-nucleon reactions at fixed target and LHC energies.


title:
Implications of the HERA events for the R-parity breaking SUSY signals
  at Tevatron

abstract:
  I report here on the systematic analysis at Tevatron of the R-parity
violating SUSY signals which correspond to the possible solution of anomalous
HERA events.


title: Energy Scale(s) and Next-to-leading BFKL Equation

abstract:
  We complete the calculation of the next-to-leading kernel of the BFKL
equation, by disentangling its energy-scale dependent part from the impact
factor corrections in large-k dijet production. Using the irreducible part
previously obtained,we derive the final form of the kernel eigenvalue and of
the hard Pomeron shift for various scales. We also discuss the scale
changes,the physical equivalence of a class of scales, and how to use collinear
safe ones.


title:
Regge trajectories and quarkonium spectrum from a first principle
  Salpeter equation

abstract:
  We compute the heavy-heavy, light-light and light-heavy quarkonium spectrum
starting from a first principle Salpeter equation obtained in a preceding
paper. We neglect spin-orbit structures and exclude from our treatment the
light pseudoscalar states which in principle would require the use of the full
Bethe-Salpeter equation due to the chiral symmetry breaking problem. For the
rest we find an overall good agreement with the experimental data. In
particular for the light-light case we find straight Regge trajectories with
the right slope and intercepts. The strong coupling constant $\alpha_s$, the
string tension $\sigma$ occurring in the potential and the heavy quark masses
are taken from the heavy quarkonium semirelativistic fit with only a small
rearrangement. The light quark masses are set equal to baricentral value of the
current quark masses as reported by the particle data group. For what concerns
the light-light and the light-heavy systems the calculation is essentially
parameter free.


title: Measuring the Supersymmetry Lagrangian

abstract:
  The parameters of the supersymmetry Lagrangian are the place where experiment
and theory will meet. We show that measuring them is harder than has been
thought, particularly because of large unavoidable dependences on phases.
Measurements are only guaranteed if a lepton collider with a polarized beam and
sufficient energy to produce the relevant sparticles is available. Current
limits on superpartner masses, WIMPs, and the supersymmetric Higgs are not
general, and need re-evaluation. We also tentatively define the MRM (Minimum
Reasonable Model), whose parameters may be measurable at LEP, FNAL and LHC.


title:
Effective Lagrangian for SU(3)_c gluodynamics from lattice color
  dielectrics

abstract:
  Small momenta limit of the lattice color dielectric model in the SU(3)_c case
is considered. We show that in that limit the model involves a coarse-grained
gluon field, a color singlet "bleached gluon" field, and both color singlet and
octet rank two symmetric tensor fields constructed from the first order
derivatives of a vector field. In contradistinction from other approaches we do
not obtain scalar color dielectric fields directly, but they can be introduced
as traces of the tensor fields.


title:
Implications of Hadron Collider Observables on Parton Distribution
  Function Uncertainties

abstract:
  Standard parton distribution function sets do not have rigorously quantified
uncertainties. In recent years it has become apparent that these uncertainties
play an important role in the interpretation of hadron collider data. In this
paper, using the framework of statistical inference, we illustrate a technique
that can be used to efficiently propagate the uncertainties to new observables,
assess the compatibility of new data with an initial fit, and, in case the
compatibility is good, include the new data in the fit.


title: Strong Dissipative Behavior in Quantum Field Theory

abstract:
  We study under which conditions an overdamped regime can be attained in the
dynamic evolution of a quantum field configuration. Using a real-time
formulation of finite temperature field theory, we compute the effective
evolution equation of a scalar field configuration, quadratically interacting
with a given set of other scalar fields. We then show that, in the overdamped
regime, the dissipative kernel in the field equation of motion is closely
related to the shear viscosity coefficient, as computed in scalar field theory
at finite temperature. The effective dynamics is equivalent to a time-dependent
Ginzburg-Landau description of the approach to equilibrium in phenomenological
theories of phase transitions. Applications of our results, including a
recently proposed inflationary scenario called ``warm inflation'', are
discussed.


title:
Quark Mixing Possibilities in Extensions of the Standard Model and the
  Electromagnetic Current

abstract:
  The existence of new quarks may lead to their mixing with ordinary quarks. We
are particularly interested in studying the consequences such mixings could
have upon the electromagnetic current. We find that new strong flavor and
parity violating electromagnetic interactions may exist. To be specific, for
our analysis we work with the model: $SU_2 \otimes U_1 \otimes \hat{SU}_2
\otimes \hat{U}_1$, which doubles the standard electroweak sector, both in
gauge bosons and in quarks.


title: Scalar meson masses and mixing angle in a U(3)XU(3) Linear Sigma Model

abstract:
  Meson properties are considered within a U(3)\times U(3) Linear Sigma
Model(LSM). The importance of the U_A(1)-breaking term and the OZI rule
violating term in the generation of meson masses and mixing angles is stressed.
The LSM parameters are fitted to the pseudoscalar meson spectrum thus giving
predictions for scalar meson properties. The model predicts a scalar meson
nonet whose members are: {\sigma(\approx 400), f_0(980), \kappa(\approx 900)
and a_0(980)} resonances. Scalar meson mixing angle (in the {|ns>, |s>} basis)
is predicted to be \phi_S\approx -14^\circ. Therefore the f_0(980) is
predominantly strange while the \sigma(\approx 400) is mostly non-strange. The
model also gives a pseudoscalar mixing angle \phi_P\approx 35^\circ which
corresponds to \theta_P \approx -19^\circ in the singlet-octet basis.
Comparison with chiral perturbation theory shows that L_8 is saturated by
scalar mesons exchange. However, LSM predicts that L_5 is not saturated by
scalar mesons exchange as assumed in the literature.


title:
R-Symmetry in the Minimal Supersymmetric Standard Model and Beyond with
  Several Consequences

abstract:
  The supersymmetric sector of minimal supersymmetric standard model (MSSM)
possesses a U(1) R-symmetry which contains Z_2 matter parity. Non-zero neutrino
masses, consistent with a 'redefined' R-symmetry, are possible through the
see-saw mechanism and/or a pair of superheavy (mass M) SU(2)_L triplets with
vev of order M^2_W/M. If this R-symmetry is respected by the higher order
terms, then baryon number conservation follows as an immediate consequence. In
the presence of right handed neutrinos, the observed baryon asymmetry of the
universe arises via leptogenesis. An interplay of R- and Peccei-Quinn symmetry
simultaneously resolves the strong CP and mu problems.


title: Spin Effects in Heavy Quark Processes

abstract:
  In the infinite mass limit for a heavy quark its spin decouples from the QCD
dynamics, which leads to the heavy-quark spin symmetry. After a short
discussion of spin symmetry some applications are considered.


title: The Bose-Einstein effect in Monte-Carlo generators: weight methods

abstract:
  We present a method which incorporates the Bose-Einstein effect into Monte
Carlo generators for multiple production by weighting the events. Various
aspects of weight calculations are discussed in detail. We show that our method
allows to describe reasonably well a sample of data and we outline the future
tests and applications.


title: The p_T Spectrum in Heavy-Flavour Hadroproduction

abstract:
  We consider the transverse-momentum distribution of heavy flavours in
hadronic collisions. We present a formalism in which large transverse-momentum
logarithms are resummed at the next-to-leading level, and mass effects are
included exactly up to order \alpha_strong^3, so as to retain predictivity at
both small and large transverse momenta. As an example, we apply our formalism
to b production at the Tevatron.


title: Gluon and gluino penguins and the charmless decays of the b quark

abstract:
  Gluon mediated exclusive hadronic decays of b quarks are studied within the
standard model (SM) and the constrained minimally supersymmetric standard model
(MSSM). For all allowed regions of the MSSM parameter space (A, tan beta, m_0,
m_{1/2}) the penguin magnetic dipole form factor F^R_2 is dominant over the
electric dipole and can be larger than the magnetic dipole form factor of the
SM. However, overall the SM electric dipole decay amplitude F^L_1 dominates the
decay rate. The MSSM penguin contributions to the free quark decay rate
approach the 10% level for those regions of parameter space close to the
highest allowed values of tan beta (~55) for which the gluino is light
(m_{\tilde{g}} \approx 360 GeV) and lies within the range of the six d-squark
masses. In these regions the supersymmetric box amplitudes are negligible. The
MSSM phases change very little over the allowed parameter space and can lead to
significant interference with the SM amplitudes.


title:
On the Pattern of Asymmetries in the Pole Model of Weak Radiative
  Hyperon Decays

abstract:
  We study the question whether the pole-model VMD approach to weak radiative
hyperon decays can be made consistent with Hara's theorem and still yield the
pattern of asymmetries characteristic of the quark model. It is found that an
essential ingredient which governs the pattern of asymmetries is the assumed
off-shell behaviour of the parity-conserving 1/2^- 1/2^+ gamma amplitudes. It
appears that this behaviour can be chosen in such a way that the pattern
characteristic of the quark model is obtained, and yet Hara's theorem
satisfied. As a byproduct, however, all parity-violating amplitudes in weak
radiative and nonleptonic hyperon decays must then vanish in the SU(3) limit.
This is in conflict with the observed size of weak meson-nucleon couplings.


title:
Evolution, probabilistic interpretation and decoupling of orbital and
  total angular momenta in nucleon

abstract:
  The leading order evolution of parton orbital angular momenta is treated in
the probabilistic manner. As a result, the splitting probability matrix, while
coinciding with the recent explicit calculations, is expressed in the terms of
the standard spin-dependent and spin-averaged kernels. The implied relations
between spin and orbital angular momenta evolution kernels may be interpreted
as resulting from the ambiguity in the separation of the angular momenta to the
spin and orbital contributions and are likely to be valid for higher orders and
twists. Consequently, the orbital and total angular momenta may be considered
as decoupling from the spin ones, the latter being the only elements of nucleon
structure accessible via the hard scattering of polarized particles. In
particular, the partition of the total angular momenta of quarks and gluons
should be analogous to that of their momentum at any $Q^2$, generalizing the
earlier finding for asymptotic limit by Ji, Tang and Hoodbhoy.


title:
Phenomenology of $SU(3) \otimes SU(2) \otimes U(1)$ supersymmetric model
  with Dirac neutrino masses

abstract:
  We consider supersymmetric extension of standard electroweak model with Dirac
neutrino masses. In such model for significant region of the parameters
right-handed tau sneutrino is the lightest superparticle and right-handed
charged tau slepton is the next to lightest superparticle. Due to the smallness
of the neutrino masses the right-handed tau slepton is long-lived particle that
changes the standard signatures used in the search for supersymmetry at
supercolliders. The most striking signatures of such scenario is the existence
of highly ionizing tracks and excess of multilepton events that is similar to
the phenomenology of gauge-mediated supersymmetry breaking models


title: The soft scalar mass $\beta$-function

abstract:
  We present an exact formula for the $\beta$-function for the soft-breaking
scalar mass in an N=1 supersymmetric gauge theory, in the form of an operator
acting on the anomalous dimension. In particular we give the exact form for the
correction due to the $\epsilon$-scalar mass, and show that it has a
particularly simple form in the renormalisation scheme corresponding to the
exact NSVZ gauge $\beta$-function.


title: Absorption and J/psi Suppression in Heavy Ion Collisions

abstract:
  We discuss the J/psi suppression in the framework of multiple collision
models. From the analysis of the Pb-Pb NA50 data we conclude that the strength
of the absorption has increased, but we find no clear evidence for the
formation of the quark-gluon plasma.


title:
Hadron Spectra and Spectral Moments in the Decay B \to X_s \ell^+ \ell^-
  using HQET

abstract:
  We compute the leading order (in alpha_s) perturbative QCD and power
(1/m_b^2) corrections to the hadronic invariant mass and hadron energy spectra
in the decay B \to X_s \ell^+ \ell^- in standard model using the heavy quark
expansion technique (HQET). Results for the first two hadronic moments < S_H^n>
and <E_H^n>, n=1,2, are presented here working out their sensitivity on the
HQET parameters lambda_1 and \bar{\Lambda}. Data from the forthcoming B
facilities can be used to measure the short-distance contribution in B \to X_s
\ell^+ \ell^- and determine the HQET parameters from the moments <S_H^n>. This
can be combined with the analysis of semileptonic decays B \to X \ell \nu_\ell
to determine them precisely.


title: HBT correlations and charge ratios in multiple production of pions

abstract:
  The influence of the HBT effect on the multiplicity distribution and charge
ratios of independently produced pions is studied. It is shown that, for a wide
class of models, there is a critical point, where the average number of pions
becomes very large and the multiplicity distibution becomes very broad. In this
regime unusual charge ratios ("centauros", "anticentauros") are strongly
enhanced. The prospects for reaching this regime are discussed.


title: Charge quantization in a chiral bilepton gauge model

abstract:
  In the context of the standard model the quantization of the electric charge
occurs only family by family. When we consider the three families together with
massless neutrinos the electric charge is not quantized any more. Here we show
that a chiral bilepton gauge model based on the gauge group SU(3)_C X SU(3)_L X
U(1)_N explains the quantization of the electric charge when we take into
account the three families of fermions. This result does not depend on the
neutrino masses. Charge quantization occurs either the neutrinos are massless
or Dirac or Majorana massive fields.


title: Deconstructing Angular Correlations in ZH, ZZ, and WW Production at LEP2

abstract:
  We apply a generalized spin-basis analysis to associated Higgs production and
gauge boson pair production at LEP. This framework allows us to identify a
choice of spin axes for the processes e+ e- --> ZH,ZZ which leads to strikingly
different correlations among the decay products, even well above threshold.
This spin basis optimizes the difference in the angular correlations for these
two processes. In contrast, the same distributions display little contrast when
the helicity basis is used. We also apply this technique to the case of W boson
pair production.


title: Box Anomaly and $\eta' \to \pi ^+ \pi ^- \gamma$ Decay

abstract:
  In the framework of the "current scheme" of $\eta - \eta'$ mixing we
calculate the amplitude of the decay $\eta' \to \pi ^+ \pi ^- \gamma $ in the
soft limit and compare our results with recently reported values of the
phenomenological additive terms to the $\rho $--meson background.


title:
Magnetohydrodynamics of the Early Universe and the Evolution of
  Primordial Magnetic Fields

abstract:
  We show that the decaying magnetohydrodynamic turbulence leads to a more
rapid growth of the correlation length of a primordial magnetic field than that
caused by the expansion of the Universe. As an example, we consider the
magnetic fields created during the electroweak phase transition. The expansion
of the universe alone would yield a correlation length at the present epoch of
1 AU, whereas we find that the correlation length is likely of order 100 AU,
and cannot possibly be longer than $10^4$ AU for non-helical fields. If the
primordial field is strongly helical, the correlation length can be much
larger, but we show that even in this case it cannot exceed 100 pc. All these
estimates make it hard to believe that the observed galactic magnetic fields
can result from the amplification of seed fields generated at the electroweak
phase transition by the standard galactic dynamo.

categories: hep-ph astro-ph chao-dyn nlin.CD physics.plasm-ph


title:
Isospin Symmetry Breaking in the Quark Condensates, $< \bar dd>\not= <
  \bar uu>$, as Estimated from QCD Sum Rules

abstract:
  Isospin symmetry breaking in the quark condensates, $< \bar dd> \not= < \bar
uu>$, is a fundamental parameter in both the QCD sum rule studies and the
chiral perturbation theory. In this article, we apply the QCD sum rule method
to treat the hyperon mass difference ${1\over
2}(m_{\Sigma^-}+m_{\Sigma^0})-m_{\Sigma^+}$ in order to obtain a reasonable
estimate on such isospin symmetry breaking parameter $\gamma$ defined as $(<
\bar dd>-< \bar uu>)/ < \bar uu>$. Note that the electromagnetic contributions
to the particular mass difference are expected to cancel almost completely.
Using the light-quark mass difference $m_d-m_u=4\pm 1$ MeV and the experimental
data ${1\over 2}(m_{\Sigma^-}+m_{\Sigma^0})-m_{\Sigma^+}$$=5.62\pm 0.13$ MeV,
we obtain $\gamma= -0.011\pm 0.001$, a value which is slightly larger than the
commonly adopted value and is of smaller uncertainty.