title: Propagation of ultrahigh-energy neutrinos through the Earth

abstract:
  The dispersion relation in matter of ultrahigh-energy neutrinos above the
pole of the $W$ resonance ($E_{\nu} \gsim {\rm 10}^{7} {\rm GeV} $), is
studied. We perform our calculation using the real-time formulation of Thermal
Field Theory in which the massless limit for the $W$ boson is taken. The range
of active-to-sterile neutrino oscillation parameters for which there is
significant mixing enhancement during propagation through the interior of the
Earth, and therefore significant attenuation of neutrino beams in the Earth at
high energies, is estimated. Finally, this range is considered in view of the
cosmological and astrophysical constraints.


title: A D-Brane Alternative to the MSSM

abstract:
  The success of SU(5)-like gauge coupling unification boundary conditions
$g_3^2=g_2^2=5/3 g_1^2$ has biased most attempts to embed the SM interactions
into a unified structure. After discussing the limitations of the orthodox
approach, we propose an alternative that appears to be quite naturally implied
by recent developments based on D-brane physics. In this new alternative: 1)
The gauge group, above a scale of order 1 TeV, is the minimal left-right
symmetric extension $SU(3)\times SU(2)_L\times SU(2)_R\times U(1)_{B-L}$ of the
SM; 2) Quarks, leptons and Higgs fields come in three generations; 3) Couplings
unify at an intermediate string scale $M_s= 9\times 10^{11}$ GeV with boundary
conditions $g_3^2=g_L^2=g_R^2=32/3 g_{B-L}^2$. This corresponds to the natural
embedding of gauge interactions into D-branes and is different from the
standard SO(10) embedding which corresponds to $k_{B-L}=8/3$. Unification only
works in the case of three generations;
  4) Proton stability is automatic due to the presence of $Z_2$ discrete
R-parity and lepton parities. A specific Type IIB string orientifold model with
the above characteristics is constructed. The existence of three generations is
directly related to the existence of three complex extra dimensions.
  In this model the string scale can be identified with the intermediate scale
and SUSY is broken also at that scale due to the presence of anti-branes in the
vacuum.
  We discuss a number of phenomenological issues in this model including Yukawa
couplings and a built-in axion solution to the strong-CP problem. The present
framework could be tested by future accelerators by finding the left-right
symmetric extension of the SM at a scale of order 1 TeV.


title:
How open charm production and scaling violations probe the rightmost
  hard BFKL pole exchange

abstract:
  In 1994 Zakharov and the present authors argued that in color dipole (CD)
BFKL approach to DIS excitation of open charm at moderately large Q2 is
dominated by hard BFKL exchange. In view of the rapid accumulation of the
experimental data on small-x charm structure function of the proton F2cc from
HERA, we subject the issue of dominance of the rightmost hard BFKL pole
exchange to further scrutiny. Based on CD BFKL-Regge factorization we report
parameter-free predictions for the charm structure function F2cc and show that
the background to the dominant rightmost hard BFKL exchange from subleading
hard BFKL and soft-pomeron exchanges is negligible small from real
photo-production to DIS at Q2 lsim 50-100 GeV2. The agreement with the
experiment is good and lends strong support for the intercept of the rightmost
hard BFKL pole DeltaPom=alphaPom-1=0.4 as found in 1994 in the color dipole
approach. We comment on the related determination of DeltaPom from the
x-dependence of the longitudinal structure function FL(x,Q2) and of the scaling
violation dF2/dlog Q2 taken at a suitable value of Q2. \


title: The deconfinement phase transition, hadronization and the NJL model

abstract:
  One of the confident predictions of QCD is that at sufficiently high
temperature and/or density, hadronic matter should undergo a thermodynamic
phase transition to a colour deconfined state of matter - popularly called the
Quark-Gluon Plasma (QGP). In low energy effective theories of Quantum
Chromodynamics (QCD), one usually talks of the chiral transition for which a
well defined order parameter exists. We investigate the dissociation of pions
and kaons in a medium of hot quark matter decsribed by the Nambu - Jona Lasinio
(NJL) model. The decay widths of pion and kaon are found to be large but finite
at temperature much higher than the critical temperature for the chiral (or
deconfinement) transition, the kaon decay width being much larger. Thus pions
and even kaons (with a lower density compared to pions) may coexist with quarks
and gluons at such high temperatures. On the basis of such premises, we
investigate the process of hadronization in quark-gluon plasma with special
emphasis on whether such processes shed any light on acceptable low energy
effective theories of QCD.


title:
ISAJET 7.48: A Monte Carlo Event Generator for $pp$, $\bar pp$, and
  $e^+e^-$ Interactions

abstract:
  ISAJET is a Monte Carlo program which simulates $pp$, $\bar pp$ and $e^+e^-$
interactions at high energies. This document summarizes the physics underlying
the program and describes how to use it. Version~7.48 includes several new
features. Anomaly Mediated SUSY Breaking (AMSB) models and right-handed
sneutrinos have been added; the latter play a role, e.g., in inverted hierarchy
models. A new process generating $Z+\hbox{2 jets}$ based on the Helas library
and MadGraph has been added. Another new process generating Kaluza-Klein
gravitons in models with extra dimensions has been added.


title:
Electroweak Phase Transition in the MSSM: 4-Dimensional Lattice
  Simulations

abstract:
  Recent lattice results have shown that there is no Standard Model (SM)
electroweak phase transition (EWPT) for Higgs boson masses above \approx 72
GeV, which is below the present experimental limit. According to perturbation
theory and 3-dimensional (3d) lattice simulations there could be an EWPT in the
Minimal Supersymmetric Standard Model (MSSM) that is strong enough for
baryogenesis up to m_h \approx 105 GeV. In this letter we present the results
of our large scale 4-dimensional (4d) lattice simulations for the MSSM EWPT. We
carried out infinite volume and continuum limits and found a transition whose
strength agrees well with perturbation theory, allowing MSSM electroweak
baryogenesis at least up to m_h = 103 \pm 4 GeV. We determined the properties
of the bubble wall that are important for a successful baryogenesis.


title: Analyzing epsilon'/epsilon in the 1/N_c Expansion

abstract:
  We present a recent analysis of epsilon'/epsilon in the 1/N_c expansion. We
show that the 1/N_c corrections to the matrix element of Q_6 are large and
positive, indicating a Delta I=1/2 enhancement similar to the one of Q_1 and
Q_2 which dominate the CP conserving amplitude. This enhances the CP ratio and
can bring the standard model prediction close to the measured value for central
values of the parameters.


title: Thermal Field Theory in Equilibrium

abstract:
  In this talk, I review recent developments in equilibrium thermal field
theory. Screened perturbation theory and hard-thermal-loop perturbation theory
are discussed. A self-consistent $\Phi$-derivable approach is also briefly
reviewed.


title: Thermal Abundances of Heavy Particles

abstract:
  Matsumoto and Yoshimura [hep-ph/9910393] have argued that there are loop
corrections to the number density of heavy particles (in thermal equilibrium
with a gas of light particles) that are not Boltzmann suppressed by a factor of
e^(-M/T) at temperatures T well below the mass M of the heavy particle. We
argue, however, that their definition of the number density does not correspond
to a quantity that could be measured in a realistic experiment. We consider a
model where the heavy particles carry a conserved U(1) charge, and the light
particles do not. The fluctuations of the net charge in a given volume then
provide a measure of the total number of heavy particles in that same volume.
We show that these charge fluctuations are Boltzmann suppressed (to all orders
in perturbation theory). Therefore, we argue, the number density of heavy
particles is also Boltzmann suppressed.


title: Breakdown of the KLN Theorem for Charged Particles in Condensed Matter

abstract:
  The Kinoshita-Lee-Nauenberg (KLN) theorem describes the fact that inclusive
electromagnetic and weak production processes in the vacuum do not contain
singularities in the ultra-relativistic limit of zero mass. When these
production processes occur in condensed matter, the KLN theorem fails. One
consequence of this failure is that precision lifetime determinations of
stopped muons will depend on the nature of the surrounding material.


title: Diffraction: A New Approach

abstract:
  A phenomenological model of hard diffraction is presented, in which the
structure of the Pomeron is derived from the structure of the parent hadron.
Predictions for diffractive deep inelastic scattering are compared with data.


title:
Search Strategies for Non-Standard Higgs Bosons at Future e^+e^-
  Colliders

abstract:
  Already in the simplest two-Higgs-doublet model with CP violation in the
Higgs sector, the $3\times3$ mixing matrix for the neutral Higgs bosons can
substantially modify their couplings, thereby endangering the ``classical''
Higgs search strategies. However, there are sum rules relating Yukawa and
Higgs-Z couplings which ensure that the ZZ, $b\anti b$ and $t\anti t$ couplings
of a given neutral 2HDM Higgs boson cannot all be simultaneously suppressed.
This result implies that any single Higgs boson will be detectable at an e^+e^-
collider if the Z+Higgs, $b\anti b+$Higgs {\it and} $t\anti t+$Higgs production
channels are all kinematically accessible {\it and} if the integrated
luminosity is sufficient. We explore, as a function of Higgs mass, the
luminosity required to guarantee Higgs boson detection, and find that for
moderate $\tan\beta$ values the needed luminosity is unlikely to be available
for all possible mixing scenarios. The additional difficulties for the case
when the two-doublet Higgs sector is extended by adding one more singlet are
summarized. Implications of the sum rules for Higgs discovery at the Tevatron
and LHC are briefly discussed.


title: The Spin Structure of the Proton

abstract:
  It is shown that the proton "spin crisis'' or "spin puzzle" can be understood
by the relativistic effect of quark transversal motions due to the
Melosh-Wigner rotation. The quark helicity $\Delta q$ measured in polarized
deep inelastic scattering is actually the quark spin in the infinite momentum
frame or in the light-cone formalism, and it is different from the quark spin
in the nucleon rest frame or in the quark model. The flavor asymmetry of the
Melosh-Wigner effect for the valence $u$ and $d$ quarks and the intrinsic sea
$q \bar{q}$ pairs are also the important ingredients in a SU(6)
quark-spectator-diquark model framework to understand the "spin puzzle". Such a
picture of the spin structure can be tested by use of several simple relations
to measure the quark spin distributions in the quark model.


title: Masses of the Goldstone modes in the CFL phase of QCD at finite density

abstract:
  We construct the U_L(3) x U_R(3) effective lagrangian which encodes the
dynamics of the low energy pseudoscalar excitations in the Color-Flavor-Locking
superconducting phase of QCD at finite quark density. We include the effects of
instanton-induced interactions and study the mass pattern of the pseudoscalar
mesons. A tentative comparison with the analytical estimate for the gap
suggests that some of these low energy momentum modes are not stable for
moderate values of the quark chemical potential.


title:
The interplay between perturbative QCD and power corrections: the
  description of scaling or automodelling limit violation in deep-inelastic
  scattering

abstract:
  The summary of the results of our next-to-next-to-leading fits of Tevatron
experimental data for $xF_3$ structure function of the $\nu N$ deep-inelastic
scattering is given. The special attention is paid to the extraction of twist-4
contributions and demonstration of the interplay between these effects and
higher-order perturbative QCD corrections. The factorization and
renormalization scale uncertainties of the results obtained are analysed


title:
On Importance of Inelastic Rescatterings in Pion Double Charge Exchange
  on Nuclei

abstract:
  Different aspects of the Gribov--Glauber approach for calculation of
inclusive pion double charge exchange (DCX) on nuclei are investigated.
Recently we have shown that inelastic rescatterings (IR) with two (and more)
pions in the intermediate states give an important contribution to the process
of DCX at energies above $\sim0.6 GeV$. In this paper we use the one pion
exchange model to study in details amplitudes of two pion production. This
allows us to verify theoretical assumptions made in the previous paper and to
predict cross section for the forward inclusive pion DCX at energies $\ga1
GeV$, where IR dominate over the conventional DCX mechanism of two sequential
single charge exchanges.


title: Elements of Baryogenesis

abstract:
  Basic ingredients of the theory of baryogenesis are reviewed with emphasis on
out-of-equilibrium decays of heavy particles. The present use of kinetic theory
is explained and some attempts to go beyond the classical Boltzmann equations
are discussed.


title: On determining CKM angles alpha and beta

abstract:
  Because the Bd -> J/psi Ks asymmetry determines only sin(2 beta), a discrete
ambiguity in the true value of beta remains. This note reviews how the
ambiguity can be removed. Extractions of the CKM angle alpha are discussed
next. Some of the methods require very large data samples and will not be
feasible in the near future. In the near future, semi-inclusive CP-violating
searches could be undertaken, which are reviewed last.


abstract:
  The QED radiative corrections to virtual Compton scattering (reaction $e p
\to e p \gamma$) are calculated to first order in $\alpha_{em} \equiv e^2 / 4
\pi$. A detailed study is presented for the one-loop virtual corrections and
for the first order soft-photon emission contributions. Furthermore, a full
numerical calculation is given for the radiative tail, corresponding with
photon emission processes, where the photon energy is not very small compared
with the lepton momenta. We compare our results with existing works on elastic
electron-proton scattering, and show for the $e p \to e p \gamma$ reaction how
the observables are modified due to these first order QED radiative
corrections. We show results for both unpolarized and polarized observables of
the virtual Compton scattering in the low energy region (where one is sensitive
to the generalized polarizabilities of the nucleon), as well as for the deeply
virtual Compton scattering.


title: Four--Neutrino Oscillation Solutions of the Solar Neutrino Problem

abstract:
  We present an analysis of the neutrino oscillation solutions of the solar
neutrino problem in the framework of four-neutrino mixing where a sterile
neutrino is added to the three standard ones. We perform a fit to the full data
set corresponding to the 825-day Super-Kamiokande data sample as well as to
Chlorine, GALLEX and SAGE and Kamiokande experiments. In our analysis we use
all measured total event rates as well as all Super-Kamiokande data on the
zenith angle dependence and the recoil electron energy spectrum. We consider
both transitions via the Mikheyev-Smirnov-Wolfenstein (MSW) mechanism as well
as oscillations in vacuum (just-so) and find the allowed solutions for
different values of the additional mixing angles. This framework permits
transitions into active or sterile neutrinos controlled by the additional
parameter $\cos^2(\vartheta_{23}) \cos^2(\vartheta_{24})$ . We discuss the
maximum allowed values of this additional mixing parameter for the different
solutions.


title: The eta' in baryon chiral perturbation theory

abstract:
  We include in a systematic way the eta' in baryon chiral perturbation theory.
The most general relativistic effective Lagrangian describing the interaction
of the lowest lying baryon octet with the Goldstone boson octet and the eta' is
presented up to linear order in the derivative expansion and its heavy baryon
limit is obtained. As explicit examples, we calculate the baryon masses and the
pi N sigma-term up to one-loop order in the heavy baryon formulation. A
systematic expansion in the meson masses is possible, and appearing divergences
are renormalized.


title: Higgs Boson Production at the LHC with Soft Gluon Effects

abstract:
  We present results of QCD corrections to Higgs boson production at the CERN
Large Hadron Collider. Potentially large logarithmic contributions from
multiple soft-gluon emission are summed up to all order in the strong coupling.
Various kinematical distributions, including the Higgs transverse momentum, are
predicted with O(alpha_s^3) precision. Comparison is made to outputs of the
popular Monte Carlo event generator PYTHIA.


title: Generalized Mesons in Dense QCD

abstract:
  QCD superconductors in the color-flavor-locked (CFL) phase support
excitations (generalized mesons) that can be described as pairs of particles or
holes (rather than particle-hole) around a gapped Fermi surface. In weak
coupling and to leading logarithm accuracy the scalar and pseudoscalar
excitations are massless and the vector and axial-vector excitations are
massive and degenerate. The massless scalar excitations are combined with the
longitudinal gluons leading to the Meissner effect in the CFL phase. The mass
of the composite vector excitations is close to twice the gap in weak coupling,
but goes asymptotically to zero with increasing coupling thereby realizing
Georgi's vector limit in cold and dense matter. We discuss the possible mixing
of the composite scalar and vector excitations with the gluons, their possible
coupling to the modified photons and their decay into light pseudoscalars in
the CFL phase. The issue of hidden gauge-symmetry in the QCD superconductor is
critically examined. The physical implications of our results on soft dilepton
and neutrino emission in cold and dense matter are briefly discussed.


title: A Comparison of Spin Observable Predictions for RHIC

abstract:
  There have been many versions of spin-dependent parton distributions in the
literature. Although most agree with present data within uncertainties, they
are based upon different physical assumptions. Some physical models are
discussed and the corresponding predictions for double spin asymmetries are
shown. A summary of the most feasible measurements in the appropriate kinematic
regions at RHIC, which should yield the most useful information about the
polarized gluon distribution, is given.


title: Separating Different Models from Measuring $\alpha, \beta, \gamma$

abstract:
  New physics effects on the $B^0-\bar{B}^0$ mixing and B-decay amplitudes are
discussed. By a combined analysis, the model of new physics can be partially
distinguished.It is emphasized that the extraction of unitarity angles $\beta$
and $\gamma$ through rare decay $K\to \pi\nu\tilde{\nu}$ and charged B decay
$B^{\pm}\to DK^{\pm}$ respectively is not likely to be affected by new physics.
Such an observation could be used to distinguish the new physics effects from
different mode ls. For instance, the top quark two-Higgs doublet model can be
easily separated from those models without new phase in B-decay amplitudes, and
can be further distinguished from the most general two Higgs doublet model by
its absence of new phase in the $B^0-\bar{B}^0$ mixing.


title:
On the Mixing of the Scalar Mesons $f_0(1370)$, $f_0(1500)$ and
  $f_0(1710)$

abstract:
  Based on a $3\times3$ mass matrix describing the mixing of the scalar states
$f_0(1370)$, $f_0(1500)$ and $f_0(1710)$, the hadronic decays of the three
states are investigated. Taking into account the two possible assumptions
concerning the mass level order of the bare states
$|N>=|u\bar{u}+d\bar{d}>/\sqrt{2}$, $|S>=|s\bar{s}>$ and $|G>=|gg>$ in the
scalar sector, $M_G > M_S > M_N$ and $M_G > M_N > M_S$, we obtain the
glueball-quarkonia content of the three states by solving the unlinear
equations. Some predictions about the decays of the three states in two cases
are presented, which can provide a stringent consistency check of the two
assumptions.


title:
Chiral phase transition at high temperature and density in the QCD-like
  theory

abstract:
  The chiral phase transition at finite temperature T and/or chemical potential
$\mu$ is studied using the QCD-like theory with a variational approach. The
``QCD-like theory'' means the improved ladder approximation with an infrared
cutoff in terms of a modified running coupling. The form of
Cornwall-Jackiw-Tomboulis effective potential is modified by the use of the
Schwinger-Dyson equation for generally nonzero current quark mass. We then
calculate the effective potential at finite T and/or $\mu$ and investigate the
phase structure in the chiral limit. We have a second-order phase transition at
$T_c=129$ MeV for $\mu=0$ and a first-order one at $\mu_c=422$ MeV for T=0. A
tricritical point in the T-$\mu$ plane is found at T=107 MeV, $\mu=210$ MeV.
The position is close to that of the random matrix model and some version of
the Nambu-Jona-Lasinio model.


title: Brane-Universe in Six Dimensions with Two Times

abstract:
  Brane-Universe model embedded in 6-dimensional space-time with the signature
(2+4) is considered. A matter is gravitationally trapped in three space
dimensions, but both time-like directions are open. Choosing of the dimension
and the signature of the model is initiated with the conformal symmetry for
massless particles and any point in our world can be (1+1) string-like object.


title: Outstanding problems in the phenomenology of hard diffractive scattering

abstract:
  This paper is a summary of the discussion within the Diffractive and Low-x
Physics Working Group at the 1999 Durham Collider Workshop of the
interpretation of the Tevatron and HERA measurements of inclusive hard
diffraction.


title: Standard and exotic interpretations of the atmospheric neutrino data

abstract:
  The present status of some theoretical interpretations of the atmospheric
neutrino deficit is briefly discussed. Specifically, we show the results for
the FC mechanism and for the standard oscillation hypothesis, both in the
active and in the sterile channels. All these mechanisms are able to fit the
present data to a good statistical level. Among them, the nu_mu --> nu_tau
oscillation is certainly the best explanation to the atmospheric neutrino
deficit, providing a remarkably good agreement with the data.


title: Baryon Number Conservation and Statistical Production of Antibaryons

abstract:
  The statistical production of antibaryons is considered within the canonical
ensemble formulation. We demonstrate that the antibaryon suppression in small
systems due to the exact baryon number conservation is rather different in the
baryon-free (B=0) and baryon-rich (B>1) systems. At constant values of
temperature and baryon density in the baryon-rich systems the density of the
produced antibaryons is only weakly dependent on the size of the system. For
realistic hadronization conditions this dependence appears to be close to
B/(B+1) which is in agreement with the preliminary data of the NA49
Collaboration for the antiproton/pion ratio in nucleus-nucleus collisions at
the CERN SPS energies. However, a consistent picture of antibaryon production
within the statistical hadronization model has not yet been achieved. This is
because the condition of constant hadronization temperature in the baryon-free
systems leads to a contradiction with the data on the antiproton/pion ratio in
e+e- interactions.


title: Weak form factors for heavy meson decays: an update

abstract:
  We calculate the form factors for weak decays of $B_{(s)}$ and $D_{(s)}$
mesons to light pseudoscalar and vector mesons. To reveal the intimate
connection between different decay modes and to be able to perform the
calculations in the full physical $q^2$-region we use a relativistic dispersion
approach based on the constituent quark picture. This approach gives the form
factors as relativistic double spectral representations in terms of the wave
functions of the initial and final mesons. The form factors have the correct
analytic properties and satisfy general requirements of nonperturbative QCD in
the heavy quark limit.
  The disadvantages of quark models related to ill-defined effective quark
masses and not precisely known meson wave functions are reduced by fitting the
quark model parameters to lattice QCD results for the $B\to \rho$ transition
form factors at large momentum transfers and to the measured total $D\to
(K,K^*)l\nu$ decay rates. This allows us to predict numerous form factors for
all kinematically accessible $q^2$ values.


title: Relic neutralinos: update on neutralino-nucleon scalar cross-section

abstract:
  We discuss the effect induced on the neutralino-nucleon scalar cross-section
by the present uncertainties in the values of the quark masses and of the quark
scalar densities in the nucleon. We examine the implications of this aspect on
the determination of the neutralino cosmological properties, as derived from
measurements of WIMP direct detection. We show that, within current theoretical
uncertainties, the DAMA annual modulation data are compatible with a neutralino
as a major dark matter component, to an extent which is even larger than the
one previously derived.


title: Unification through extra dimensions at two loops

abstract:
  The presence of an extra dimension of size R\equiv M_c^{-1} introduces
corrections of order (\mu/M_c)\alpha to the gauge and Yukawa couplings and
accelerates their running at scales \mu larger than M_c. This could result in a
grand unification scale M_X\approx 20 M_c. We study the corrections at the
two-loop level. We find corrections of order (\mu/M_c)\alpha^2 for the gauge
couplings and of order (\mu/M_c)^2\alpha^2 for the Yukawa couplings. Therefore,
in the Yukawa sector one and two-loop contributions can be of the same order
below M_X. We show that in the usual scenarios the dominant gauge and Yukawa
couplings are decreasing functions of the scale, in such a way that
(\mu/M_c)\alpha becomes approximately constant and two-loop contributions
introduce just a 30% correction which does not increase with the scale.


title: Spontaneous Symmetry Breaking and Chiral Symmetry

abstract:
  In this introductory lecture, some basic features of the spontaneous symmetry
breaking are discussed. More specifically, $\sigma $-model, non-linear
realization, and some examples of spontaneous symmetry breaking in the
non-relativistic system are discussed in details. The approach here is more
pedagogical than rigorous and the purpose is to get some simple explanation of
some useful topics in this rather wide area. .


title:
The Solar Neutrino Problem in the Light of a Violation of the
  Equivalence Principle

abstract:
  We have found that long-wavelength neutrino oscillations induced by a tiny
breakdown of the weak equivalence principle of general relativity can provide a
viable solution to the solar neutrino problem.


title: Aspects of Quantum Chromodynamics

abstract:
  These lectures provide an overview of Quantum Chromodynamics (QCD), the SU(3)
gauge theory of the strong interactions. The running of the strong coupling and
the associated property of Asymptotic Freedom are analyzed. Some selected
experimental tests and the present knowledge of $\alpha_s$ and the quark masses
are briefly summarized. A short description of the QCD flavour symmetries and
the dynamical breaking of chiral symmetry is also given.


title: On the azimuthal asymmetries in DIS

abstract:
  Using the recent experimental data on the left right asymmetry in
fragmentation of transversely polarized quarks and the theoretical calculation
of the proton transversity distribution in the effective chiral quark soliton
model we explain the azimuthal asymmetries in semi-inclusive hadron production
on longitudinal (HERMES) and transversely (SMC) polarized targets with no free
parameters. On this basis we state that the proton transversity distribution
could be successfully measured in future DIS experiments with longitudinally
polarized target.


title:
Predicitions for high-energy real and virtual photon-photon scattering
  from color dipole BFKL-Regge factorization

abstract:
  High-energy virtual photon-virtual photon scattering can be viewed as
interaction of small size color dipoles from the beam and target photons, which
makes $\gamma^{*}\gamma^{*}, \gamma^{*}\gamma$ scattering at high energies
(LEP, LEP200 & NLC) an indispensable probe of short distance properties of the
QCD pomeron exchange. Based on the color dipole representation, we investigate
consequences for the $\gamma^{*}\gamma^{*},\gamma^{*}\gamma$ scattering of the
incorporation of asymptotic freedom into the BFKL equation which makes the QCD
pomeron a series of isolated poles in the angular momentum plane. The emerging
color dipole BFKL-Regge factorization allows us to relate in a
model-independent way the contributions of each BFKL pole to
$\gamma^{*}\gamma^{*},\gamma^{*} \gamma$ scattering and DIS off protons.
Numerical predictions based on our early works on color dipole BFKL
phenomenology of DIS on protons are in a good agreement with the experimental
data on the photon structure function $F_{2\gamma}$ and most recent data on the
$\gamma^*\gamma^*$ cross section $\sigma^{\gamma^*\gamma^*}(Y)$ from OPAL and
L3 experiments at LEP200.
  We discuss the role of non-perturbative dynamics and predict pronounced
effect of the Regge-factorization breaking due to large unfactorizable
non-perturbative corrections to the perturbative vacuum exchange. We comment on
the salient features of the BFKL-Regge expansion for
$\gamma^{*}\gamma^{*},\gamma^{*}\gamma$ scattering including the issue of
decoupling of subleading BFKL poles and the soft plus rightmost hard BFKL pole
dominance .


title: CP Violaing Phases In SUSY GUT Models

abstract:
  Supersymmetric CP violating phases are examined within the framework of
gravity mediated supergravity grand unified models with R parity invariance for
models with a light ($\stackrel{<}{\sim} 1$ TeV) particle spectrum. In the
minimal model, the nearness of the t quark Landau pole naturally suppresses the
t-quark cubic soft breaking parameter at the electroweak scale allowing the
electron and neutron experimental electric dipole moment (EDM) constraints to
be satisfied with a large GUT scale phase. However, the EDM constraints require
that $\theta_B$, the quadratic soft breaking parameter phase be small at the
electroweak scale unless tan$\beta\stackrel{<}{\sim}3$, which then implies that
at the GUT scale this phase must be large and highly fine tuned to satisfy
radiative breaking of $SU(2)\times U(1)$. Similar results hold for non minimal
models, and a possible GUT model is discussed where all GUT scale CP violating
phases are naturally small (i.e. O($10^{-2})$). An interesting D-brane model is
examined which enhances the size of the phases over much of the parameter space
at the electroweak sector for tan$\beta\stackrel{<}{\sim} 5$, but still
possesses the fine tuning problem at the GUT scale.


title: Reheating and Supersymmetric Flat-Direction Baryogenesis

abstract:
  We re-examine Affleck-Dine baryo/leptogenesis from the oscillation of
condensates along flat directions of the supersymmetric standard model, which
attained large vevs at the end of inflationary epoque. The key observation is
that superpotential interactions couple the flat directions to other fields,
which acquire masses induced by the flat-direction vev that may be sufficiently
small for them to be kinematically accessible to inflaton decay. The resulting
plasma of inflaton decay products then may act on the flat directions via these
superpotential Yukawa couplings, inducing thermal masses and
supersymmetry-breaking A terms. In such cases the flat directions start their
oscillations at an earlier time than usually estimated. The oscillations are
also terminated earlier, due to evaporation of the flat direction condensate
produced by its interaction with the plasma of inflaton decay products. In
these cases we find that estimates for the resulting baryon/lepton asymmetry of
the universe are substantially altered. We identify scenarios for the Yukawa
couplings to the flat directions, and the order and mass scale of
higher-dimensional superpotential interactions that set the initial flat
direction vev, that might lead to acceptable baryo/leptogenesis.


title: Color, Spin, and Flavor-Dependent Forces in Quantum Chromodynamics

abstract:
  A simple generalization of the Breit Interaction explains many qualitative
features of the spectrum of hadrons.


title: The atmospheric neutrino anomaly without maximal mixing?

abstract:
  We consider a pattern of neutrino masses in which there is an approximate
mass degeneracy between the two mass eigenstates most coupled to the $\nu_\mu$
and $\nu_\tau$ flavour eigenstates. Earth-matter effects can lift this
degeneracy and induce an effectively maximal mixing between these two
generations. This occurs if $\nu_e$'s contain comparable admixtures of the
degenerate eigenstates, even rather small ones. This provides an explanation of
the atmospheric neutrino anomaly in which the {\it ab initio} introduction of a
large mixing angle is not required. To test this possibility we perform a novel
and detailed analysis of the 52 kiloton-year SuperKamiokande data, and we find
that in a large region of parameter space the corresponding confidence levels
are excellent. The most recent results from the Chooz reactor experiment,
however, severely curtail this region, so that the conventional scenario with
nearly maximal mixing angles --which we also analyse in detail-- is supported
by the data.


title:
Motion of a scalar field coupled to a Yang Mills field reformulated
  locally with some gauge invariant variables

abstract:
  This paper exposes a reformulation of some gauge theories in terms of
explicitly gauge-invariant variables. We show in the case of Scalar QED that
the classical theory can be reformulated locally with some gauge invariant
variables. We discuss the form of some realistic asymptotic solutions to these
equations. The equations of motion are then also reformulated in the
non-abelian case.


title: Cosmological Constraints on the MSSM

abstract:
  I discuss recent developments in the study of cosmological limits on the
Minimal Supersymmetric Standard Model (MSSM). In particular, I focus on the
effect of neutralino-stau coannihilation on the relic abundance of neutralinos,
and I give examples where the cosmologically derived limits on the
supersymmetric parameters are relaxed, and one example (CP violating phases)
where they are not.


title: Constraints on the Gluon Density from Lepton Pair Production

abstract:
  The hadroproduction of lepton pairs with mass Q and finite transverse
momentum Q_T is described in perturbative QCD by the same partonic subprocesses
as prompt photon production. We demonstrate that, like prompt photon
production, lepton pair production is dominated by quark-gluon scattering in
the region Q_T>Q/2. This feature leads to sensitivity to the gluon density in
kinematical regimes accessible in collider and fixed target experiments, and it
provides a new independent method for constraining the gluon density.


title: Neutrino Conversions in Active Galactic Nuclei

abstract:
  I discuss the possibility of production of high energy cosmic neutrinos (E
\geq 10^{6} GeV) in cores of active galactic nuclei and study some of the
effects of neutrino mixing on their subsequent propagation. I also discuss the
prospects for observations of these high energy cosmic neutrinos in new km^{2}
surface area underwater/ice neutrino telescopes.


title: Neutrino Masses and Mixing one Decade from Now

abstract:
  We review the status of neutrino masses and mixings in the light of the solar
and atmospheric neutrino data. The result from the LSND experiment is also
considered. We discuss the present knowledge and the expected sensitivity to
the neutrino mixing parameters in the simplest schemes proposed to reconcile
these data some of which include a light sterile neutrino in addition to the
three standard ones.


title:
Evolution of twist-three parton distributions in QCD beyond the large
  N_c limit

abstract:
  We formulate a consistent 1/N_c^2 expansion of the QCD evolution equations
for the twist-three quark distributions g_2(x,Q^2), h_L(x,Q^2) and e(x,Q^2)
based on the interpretation of the evolution as a three-particle
quantum-mechanical problem with hermitian Hamiltonian. Each distribution
amplitude can be decomposed in contributions of partonic components with
DGLAP-type scale dependence. We calculate the 1/N_c^2 corrections to the
evolution of the dominant component with the lowest anomalous dimension - the
only one that survives in the large-N_c limit - and observe a good agreement
with the exact numerical results for N_c=3. The 1/N_c^2 admixture of operators
with higher anomalous dimensions is shown to be concentrated at a few lowest
partonic components and in general is rather weak.


title: Large-angle Bhabha scattering and luminosity at Daphne

abstract:
  The accurate knowledge of luminosity at e^+ e^- flavour factories requires
the precision calculation of the Bhabha cross section at large scattering
angles. In order to achieve a theoretical accuracy at the 0.1% level, the
relevant effect of QED radiative corrections is taken into account in the
framework of the Parton Shower method, which allows exclusive event generation.
On this scheme, a Monte Carlo event generator (BABAYAGA) is developed for data
analysis. To test the reliability of the approach, a benchmark calculation,
including exact O(alpha) corrections and higher-order leading logarithmic
contributions, is developed as well, implemented in a Monte Carlo integrator
(LABSPV) and compared in detail with the BABAYAGA predictions. The effect of
initial-state and final-state radiation, O(alpha) next-to-leading and
higher-order leading corrections is investigated and discussed in the presence
of realistic event selections. The theoretical precision of BABAYAGA is
estimated to be at the 0.5% level.


title:
Long distance contribution to $B^- \to K^- K^- \pi^+$, - a searching
  ground mode for new physics

abstract:
  The decay $B^- \to K^- K^- \pi^+$ has been sugested as a test for minimal
supersymmetric standard model and for supersymmetric models with R-parity
violating couplings, in view of its extreme smallnesss in the standard model.
We calculate two long distance contributions to this decay, that associated
with $DD$ and $D\pi$ intermediate states and that induced by virtual $D$, $\pi$
mesons. The branching ratio due to these contributions is $6 \times 10^{-12}$,
which is somewhat smaller than the standard model short distance result,
leaving this decay free for the search of new physics.


title:
Reexamination of the Constraint on Topcolor-Assisted Technicolor Models
  from R_b

abstract:
  Recent study on the charged top-pion correction to R_b shows that it is
negative and large, so that the precision experimental value of R_b gives rise
to a severe constraint on the topcolor-assisted technicolor models such that
the top-pion mass should be of the order of 1 TeV. In this paper, we restudy
this constraint by further taking account the extended technicolor gauge boson
correction which is positive. With this positive contribution to R_b, the
constraint on the topcolor-assisted technicolor models from R_b changes
significantly. The top-pion mass is allowed to be in the region of a few
hundred GeV depending on the models.


title: Applications of QCD

abstract:
  Talk given at XIXth International Symposium on Lepton and Photon Interactions
at High Energies (LP 99), Stanford, California, 9-14 August 1999.


title: Resummation of Nonalternating Divergent Perturbative Expansions

abstract:
  A method for the resummation of nonalternating divergent perturbation series
is described. The procedure constitutes a generalization of the Borel-Pad\'{e}
method. Of crucial importance is a special integration contour in the complex
plane. Nonperturbative imaginary contributions can be inferred from the purely
real perturbative coefficients. A connection is drawn from the quantum field
theoretic problem of resummation to divergent perturbative expansions in other
areas of physics.


title: phi -> pi0 pi0 gamma Decay within a U(3)x U(3) Linear Sigma Model

abstract:
  We show that therecently observed pion invariant mass distribution of the phi
->pi0 pi0 gamma decay can be satisfactorily described by the chiral U(3) X U(3)
Linear Sigma Model.


title: A Monte Carlo for BFKL Physics

abstract:
  Virtual photon scattering in e^+e^- collisions can result in events with the
electron-positron pair at large rapidity separation with hadronic activity in
between. The BFKL equation resums large logarithms that dominate the cross
section for this process. We report here on a Monte Carlo method for solving
the BFKL equation that allows kinematic constraints to be taken into account.
The application to e^+e^- collisions is in progress.


title: Gluon Radiation in Top Production and Decay

abstract:
  We present the results of an exact calculation of gluon radiation in top
production and decay at high energy electron-positron colliders. We include all
spin correlations and interferences, the bottom quark mass, and finite top
width effects in the matrix element calculation. We study properties of the
radiated gluons and implications for top mass measurement.


title: BFKL Monte Carlo for Dijet Production at Hadron Colliders

abstract:
  The production of jet pairs at large rapidity difference at hadron colliders
is potentially sensitive to BFKL physics. We present the results of a BFKL
Monte Carlo calculation of dijets at the Tevatron. The Monte Carlo incorporates
kinematic effects that are absent in analytic BFKL calculations; these effects
significantly modify the behavior of dijet cross sections.


title: Z' Bosons and Kaluza-Klein Excitations at Muon Colliders

abstract:
  After an extremely brief overview of the discovery reach for Z' bosons, we
will discuss the physics of Kaluza-Klein(KK) excitations of the Standard Model
gauge bosons that can be explored by a high energy muon collider in the era
after the LHC and TeV Linear Collider. We demonstrate that the muon collider is
a necessary ingredient in the unraveling the properties of such KK states and,
perhaps, proving their existence.


title: Featuring the structure functions geometry

abstract:
  We consider geometrical properties of the polarized and unpolarized structure
functions and provide definition for the $b$--dependent structure functions. It
is shown that unitarity does not allow factorized form of the structure
functions over the $x$ and $b$ variables. We conclude that the spin of
constituent quark has a significant orbital angular momentum component.


title:
Bloch-Nordsieck violating electroweak corrections to inclusive TeV scale
  hard processes

abstract:
  We point out that, since the colliders initial states (e+ e-,p p, p pbar, ...
) carry a definite nonabelian flavor, electroweak radiative corrections to
inclusive hard cross sections at the TeV scale are affected by peculiar
Bloch-Nordsieck violating double logs. We recall the setup of soft cancellation
theorems, and we analyze the magnitude of the noncancelling terms in the
example of electron - positron annihilation into hadrons.


title: On gauge unification in Type I/I' models

abstract:
  We discuss whether the (MSSM) unification of gauge couplings can be
accommodated in string theories with a low (TeV) string scale. This requires
either power law running of the couplings or logarithmic running extremely far
above the string scale. In both cases it is difficult to arrange for the
multiplet structure to give the MSSM result. For the case of power law running
there is also enhanced sensitivity to the spectrum at the unification scale.
For the case of logarithmic running there is a fine tuning problem associated
with the light closed string Kaluza Klein spectrum which requires gauge
mediated supersymmetry breaking on the ``visible'' brane with a dangerously low
scale of supersymmetry breaking. Evading these problems in low string scale
models requires a departure from the MSSM structure, which would imply that the
success of gauge unification in the MSSM is just an accident.


title:
Scalable Parallel Implementation of Geant4 Using Commodity Hardware and
  Task Oriented Parallel C

abstract:
  We describe a scalable parallelization of Geant4 using commodity hardware in
a collaborative effort between the College of Computer Science and the
Department of Physics at Northeastern University. The system consists of a
Beowulf cluster of 32 Pentium II processors with 128 MBytes of memory each,
connected via ATM and fast Ethernet. The bulk of the parallelization is done
using TOP-C (Task Oriented Parallel C), software widely used in the
computational algebra community. TOP-C provides a flexible and powerful
framework for parallel algorithm development, is easy to learn, and is
available at no cost. Its task oriented nature allows one to parallelize legacy
code while hiding the details of interprocess communications. Applications
include fast interactive simulation of computationally intensive processes such
as electromagnetic showers. General results motivate wider applications of
TOP-C to other simulation problems as well as to pattern recognition in high
energy physics.


title: The State of the Standard Model

abstract:
  I quickly review the successes of quantum chromodynamics. Then I assess the
current state of the electroweak theory, making brief comments about the search
for the Higgs boson and some of the open issues for the theory. I sketch the
problems of mass and mass scales, and point to a speculative link between the
question of identity and large extra dimensions. To conclude, I return to QCD
and the possibility that its phase structure might inform our understanding of
electroweak symmetry breaking.


title: Charge symmetry violation in the parton distributions of the nucleon

abstract:
  We point out that charge symmetry violation in both the valence and sea quark
distributions of the nucleon has a non-perturbative source. We calculate this
non-perturbative charge symmetry violation using the meson cloud model, which
has earlier been successfully applied to both the study of SU(2) flavour
asymmetry in the nucleon sea and quark-antiquark asymmetry in the nucleon. We
find that the charge symmetry violation in the valence quark distribution is
well below 1%, which is consistent with most low energy tests but significantly
smaller than the quark model prediction about 5%-10%. Our prediction for the
charge symmetry violation in the sea quark distribution is also much smaller
than the quark model calculation.


title:
On conditions for the nonperturbative equivalence of ultraviolet cut-off
  and dimensional regularization schemes

abstract:
  We consider procedures through which an ultraviolet cut-off regularization
scheme can be modified to reproduce the same results for nonperturbative
renormalized Green's functions as obtained from a dimensional regularization
scheme. These issues are considered within the Dyson-Schwinger equation
framework, where ultraviolet cut-off regularization can lead to explicit
violations of gauge invariance. As a specific illustration, we consider the
electron self-energy in quenched QED_4 in both schemes and establish those
procedures for which the UV cut-off scheme can be expected to lead to the
dimensional regularization results. We also compare results from precise
numerical studies using the two types of regularization.


title: Event-by-Event Analysis and the Central Limit Theorem

abstract:
  Event-by-event analysis of heavy-ion collision events is an important tool
for the study of the QCD phase boundary and formation of a quark-gluon plasma.
A universal feature of phase boundaries is the appearance of increased
fluctuations of conserved measures as manifested by excess measure variance
compared to a reference. In this paper I consider a particular aspect of EbyE
analysis emphasizing global-variables variance comparisons and the central
limit theorem. I find that the central limit theorem is, in a broader
interpretation, a statement about the scale invariance of total variance for a
measure distribution, which in turn relates to the scale-dependent symmetry
properties of the distribution.. I further generalize this concept to the
relationship between the scale dependence of a covariance matrix for all
conserved measures defined on a dynamical system and a matrix of covariance
integrals defined on two-point measure spaces, which points the way to a
detailed description of the symmetry dynamics of a complex measure system.
Finally, I relate this generalized description to several recently proposed or
completed event-by-event analyses.


title: Of Dips, Structures and Eikonalization

abstract:
  We have investigated several models of Pomeron and Odderon contributions to
high energy elastic $pp$ and $\bar p p$ scattering. The questions we address
concern their role in this field, the behavior of the scattering amplitude (or
of the total cross-section) at high energy, and how to fit all high energy
elastic data. The data are extremely well reproduced by our approach at all
momenta and for sufficiently high energies. The relative virtues of Born
amplitudes and of different kinds of eikonalizations are considered. An
important point in this respect is that secondary structures are predicted in
the differential cross-sections at increasing energies and these phenomena
appear quite directly related to the procedure of eikonalizing the various Born
amplitudes. We conclude that these secondary structures arise naturally within
the eikonalized procedure (although their precise localization turns out to be
model dependent). The fitting procedure naturally predicts the appearance of a
zero at small $|t|$ in the real part of the even amplitude as anticipated by
general theorems. We would like to stress, once again, how important it would
be to have at LHC both $pp$ and $p \bar p$ options for many questions connected
to the general properties of high energy hadronic physics and for a check of
our predictions.


title: Chiral Expansion at Energy Scale of $\rho$-Mass

abstract:
  We study chiral expansion at $m_\rho$-scale in framework of chiral
constituent quark model. The lowest vector meson resonsances are treated as
composited fields of constituent quarks. We illustrate that, at energy scale of
$\rho$-meson mass, the chiral expansion expansion converges slowly. Therefore,
it is possible to construct a well-defined chiral effective field theory at
this energy scale, but high order correction of chiral expansion must be
included simultanously. The one-loop correction of pseudoscalar mesons is also
studied systematically. The unitarity of the model is examined and Breit-Wigner
formula for $\rho$-meson is obtained. The prediction on on-shell
$\rho\to\pi\pi$ and $\rho\to e^+e^-$ decays agree with data very well.


title:
Azimuthal Angle Distribution in $B \to K^* (\to K \pi) \ell^+ \ell^- $
  at low invariant $m_{\ell^+ \ell^-}$ Region

abstract:
  We present the angular distribution of the rare B decay, $B \to K^* (\to K
\pi) \ell^+ \ell^-$. By studying the azimuthal angle distribution in the low
invariant mass region of dileptons, we can probe new physics effects
efficiently. In particular, this distribution is found to be quite sensitive to
the ratio of the contributions from two independent magnetic moment operators,
which also contribute to $B \to K^* \gamma$. Therefore, our method can be very
useful when new physics is introduced without changing the total decay rate of
the $b \to s \gamma$. The angular distributions are compared with the
predictions of the standard model, and are shown for the cases when the
afore-mentioned ratio is different from the standard model prediction.


title: Strategy for discovering a low-mass Higgs boson at the Fermilab Tevatron

abstract:
  We have studied the potential of the CDF and DZero experiments to discover a
low-mass Standard Model Higgs boson, during Run II, via the processes
$p\bar{p}$ -> WH -> $\ell\nu b\bar{b}$, $p\bar{p}$ -> ZH ->
$\ell^{+}\ell^{-}b\bar{b}$ and $p\bar{p}$ -> ZH ->$\nu \bar{\nu} b\bar{b}$. We
show that a multivariate analysis using neural networks, that exploits all the
information contained within a set of event variables, leads to a significant
reduction, with respect to {\em any} equivalent conventional analysis, in the
integrated luminosity required to find a Standard Model Higgs boson in the mass
range 90 GeV/c**2 < M_H < 130 GeV/c**2. The luminosity reduction is sufficient
to bring the discovery of the Higgs boson within reach of the Tevatron
experiments, given the anticipated integrated luminosities of Run II, whose
scope has recently been expanded.


title: Exotic Quarkonia from Lattice QCD

abstract:
  We present non-perturbative results for the spectrum of heavy quarkonia.
Using an anisotropic formulation of Lattice QCD we achieved an unprecedented
control over statistical and systematic errors. We also study relativistic
corrections to the leading order predictions for heavy hybrids and conventional
bound states.


title: Instability of Classic Rotational Motion for Three-String Baryon Model

abstract:
  The dynamics of baryon string model Y (three-string) is considered with using
the approach that implies defining a classical motion of the system on the base
of given initial position and initial velocities of string points. The analysis
resulted, in particular, in the necessity of regarding more wide (than it was
supposed earlier) class of parametrizations of the world surface for the
adequate description of the three-string model. This approach let us to
ascertain that the classic rotational motions (flat uniform rotations) for this
string configuration are unstable. Any small asymmetric disturbances grow and
inevitably result in falling a quark into the junction.


title: Parametrization of polarized parton distribution functions

abstract:
  Polarized parton distribution functions are determined by using asymmetry A_1
data from longitudinally polarized deep inelastic scattering experiments. From
our \chi^2 analysis, polarized u-valence, d-valence, antiquark, and gluon
distributions are obtained. We propose one set of leading-order distributions
and two sets of next-to-leading-order ones as the longitudinally-polarized
parton distribution functions.


title:
Instanton propagator in scalar model: exact expression and contribution
  to instanton induced processes

abstract:
  The propagator in the instanton background in the -lambda phi^4 scalar model
in four dimensions is studied. Leading and sub-leading terms of its asymptotics
for large momenta and its on-shell double residue are calculated. These results
are applied to the analysis of the initial state and initial-final state
corrections and the calculation of the next-to-leading (propagator) correction
to the exponent of the cross section of multiparticle scattering processes.


title: Singlet parton evolution at small x: a theoretical update

abstract:
  This is an extended and pedagogically oriented version of our recent work, in
which we proposed an improvement of the splitting functions at small x which
overcomes the apparent problems encountered by the BFKL approach.


title:
Dynamics of Glueball and qqbar production in the central region of pp
  collisions

abstract:
  We explain the phi and t dependences of mesons with JPC = 0-+, 0++,1++, 2-+
and 2++ produced in the central region of pp collisions. For the 0++ and 2++
sector this reveals a systematic behaviour in the data that appears to
distinguish between qqbar and non-qqbar or glueball candidates.


title: The Strange Quark Problem in the Framework of Statistical Distributions

abstract:
  A large class of polarized and unpolarized deep inelastic data is
successfully described with Fermi-Dirac functions for the non-diffractive part
of quark parton distributions. The NLO approach used here improves the
agreement with experiment of the previous LO work. We get a broader
distribution for the strange parton s(x) than for sbar(x).


title: The KARMEN anomaly, light neutralinos and type II supernovae

abstract:
  The KARMEN experiment observes a time anomaly in events induced by pion decay
at rest. This anomaly can be ascribed to the production of a new weakly
interacting particle X with mass m_X\sim 34 MeV. We show that a recently
proposed identification of the X particle with the lightest neutralino \chi in
the frame work of the MSSM with broken R parity is in contradiction to optical
observations of type II supernovae.


title:
Parametrisation of F_2^gamma at low Q^2 and of sigma(gamma,gamma) and
  sigma(gamma^*,gamma) at high energies

abstract:
  A parametrisation of the real photon structure function F_2^gamma in the low
Q^2, low x region is formulated. It includes both the VMD and the QCD
components, the latter suitably extrapolated to the low Q^2 region and based on
arbitrary parton distributions in the photon. The parametrisation used together
with the GRV and GRS' parton densities describes reasonably well the existing
high energy data on F_2^gamma, sigma(gamma,gamma) and the low Q^2 data on
sigma(gamma^*, gamma). Predictions for sigma(gamma,gamma) and for sigma(gamma^*
,gamma) for energies which may become accessible in future linear colliders are
also given.


title:
How to calculate the quantum part of the truly nonperturbative
  Yang-Mills vacuum energy density in the axial gauge QCD

abstract:
  Using the effective potential approach for composite operators, we have
formulated a general method how to calculate the truly nonperturbative vacuum
energy density in the axial gauge QCD quantum models of its ground state. It is
defined as integrated out the truly nonperturbative part of the full gluon
propagator over the deep infrared region (soft momentum region). The nontrivial
minimization procedure makes it possible to determine the value of the soft
cutoff in terms of the corresponding nonperturbative scale parameter which is
inevitably presented in any nonperturbative model for the full gluon
propagator. If the chosen Ansatz for the full gluon propagator is a realistic
one, then our method uniquely determines the truly vacuum energy density, which
is always finite, automatically negative and it has no imaginary part (stable
vacuum). We illustrate it by considering the Abelian Higgs model of dual QCD
ground state. We have explicitly shown that the vacuum of this model without
string contributions is unstable against quantum corrections.


title: Ultra High Energy Cosmic Rays from Cosmological Relics

abstract:
  The current status of origin of Ultra High Energy Cosmic Rays (UHECR) is
reviewed, with emphasis given to elementary particle solutions to UHECR
problem, namely to Topological Defects and Super-Heavy Dark Matter (SHDM)
particles. The relic superheavy particles are very efficiently produced at
inflation. Being protected by gauge discrete symmetries, they can be long
lived. They are clustering in the Galactic halo, producing thus UHECR without
Greisen-Zatsepin-Kuzmin cutoff. Topological Defects can naturally produce
particles with energies as observed and much higher, but in most cases fail to
produce the observed fluxes. Cosmic necklaces, monopoles connected by strings
and vortons are identified as most plausible sources. The latter two of them
are also clustering in the halo and their observational predictions are
identical to those of SHDM particles.


title: Hard Loop Approach to Anisotropic Systems

abstract:
  Anisotropic systems of quarks and gluons, which at least for sufficiently
short space-time intervals can be treated as homogeneous and static, are
considered. The gluon polarization tensor of such a system is explicitly
computed within the semiclassical kinetic and Hard Loop diagrammatic theories.
The equivalence of the two approaches is demonstrated. The quark self energy is
computed as well, and finally, the dispersion relations of quarks and gluons in
the anisotropic medium are discussed.


title: Effective cross section and spatial structure of the hadrons

abstract:
  Informations about the spatial structure of parton distribution within the
hadron are provided by the ratios between the inclusive cross sections for a
pair of jets, two pairs of jets, three pairs of jets..., and so on. It results,
however that these ratios depend not only on the spatial distribution but also,
and even more, on the multiplicity distribution of the initial partons.


title: TeV Strings and Collider Probes of Large Extra Dimensions

abstract:
  Arkani-Hamed, Dimopoulos, and Dvali have proposed that the fundamental
gravitational scale is close to 1 TeV, and that the observed weakness of
gravity at long distances is explained by the presence of large extra compact
dimensions. If this scenario is realized in a string theory of quantum gravity,
the string excited states of Standard Model particles will also have TeV
masses. These states will be visible to experiment and in fact provide the
first signatures of the presence of a low quantum gravity scale. Their presence
also affects the more familiar signatures due to real and virtual graviton
emission. We study the effects of these states in a simple string model.


title: Asymptotic Gluon Shadowing

abstract:
  We examine the low Bjorken $x$ gluon distribution in nuclei in the asymptotic
region.


title: Spinodal Instabilities and the Dark Energy Problem

abstract:
  The accelerated expansion of the Universe measured by high redshift Type Ia
Supernovae observations is explained using the non-equilibrium dynamics of
naturally soft boson fields. Spinodal instabilities inevitably present in such
systems yield a very attractive mechanism for arriving at the required equation
of state at late times, while satisfying all the known constraints on models of
quintessence.


title: The Reconstruction of Trilinear Higgs Couplings

abstract:
  To establish the Higgs mechanism {\it sui generis} experimentally, the Higgs
self-interaction potential must be reconstructed. This task requires the
measurement of the trilinear and quadrilinear self-couplings, as predicted in
the Standard Model or in supersymmetric theories. The couplings can be probed
in multiple Higgs production at high-luminosity e+e- linear colliders. We
present the theoretical analysis for the production of neutral Higgs-boson
pairs in the relevant channels of double Higgs-strahlung and associated
multiple Higgs production.


title: Final state interaction in heavy hadron decay

abstract:
  I present a critical account of the final-state interaction (FSI) in two-body
B decays from viewpoint of the hadron picture. I emphasize that the phase and
the magnitude of decay amplitude are related to each other by a dispersion
relation. In a model phase of FSI motivated by experiment, I illustrate how
much the magnitude of amplitude can deviate from its factorization value by the
FSI.


title: QCD-like Theories at Finite Baryon Density

abstract:
  We study QCD-like theories with pseudoreal fermions at finite baryon density.
Such theories include two-color QCD with quarks in the fundamental
representation of the color group as well as any-color QCD with quarks in the
adjoint color representation. In all such theories the lightest baryons are
diquarks. At zero chemical potential $\mu$ they are, together with the
pseudoscalar mesons, the Goldstone modes of a spontaneously broken enlarged
chiral symmetry group. Using symmetry principles, we derive the low-energy
effective Lagrangian for these particles. We find that a second order phase
transition occurs at a value of $\mu$ equal to half the mass of the Goldstone
modes. For values of $\mu$ beyond this point the scalar diquarks Bose condense
and the diquark condensate is nonzero. We calculate the dependence of the
chiral condensate, the diquark condensate, the baryon charge density, and the
masses of the diquark and pseudoscalar excitations on $\mu$ at finite bare
quark mass and scalar diquark source. The relevance of our results to lattice
QCD calculations and to real three-color QCD at finite baryon density is
discussed.


title: Minimal Gaugino Mediation

abstract:
  We propose Minimal Gaugino Mediation as the simplest known solution to the
supersymmetric flavor and CP problems. The framework predicts a very minimal
structure for the soft parameters at ultra-high energies: gaugino masses are
unified and non-vanishing whereas all other soft supersymmetry breaking
parameters vanish. We show that this boundary condition naturally arises from a
small extra dimension and present a complete model which includes a new
extra-dimensional solution to the mu problem. We briefly discuss the predicted
superpartner spectrum as a function of the two parameters of the model. The
commonly ignored renormalization group evolution above the GUT scale is crucial
to the viability of Minimal Gaugino Mediation but does not introduce new model
dependence.


title: Cosmology of Q-balls

abstract:
  Supersymmetric extensions of the Standard Model predict the existence of
Q-balls, some of which can be entirely stable. Both stable and unstable Q-balls
can play an important role in cosmology.
  In particular, Affleck-Dine baryogenesis can result in a copious production
of stable baryonic Q-balls, which can presently exist as a form of dark matter.
Formation and decay of unstable Q-balls can also have some important effects on
baryogenesis and phase transitions.


title:
The Electric Dipole Moment and CP Violation in $B \to X_s l^+ l^-$ in
  SUGRA Models with Nonuniversal Gaugino Masses

abstract:
  The constraints of electric dipole moments (EDMs) of electron and neutron on
the parameter space in supergravity (SUGRA) models with nonuniversal gaugino
masses are analyzed. It is shown that with a light sparticle spectrum, the
sufficient cancellations in the calculation of EDMs can happen for all phases
being order of one in the small tan$\beta$ case and all phases but $\phi_{\mu}$
($|\phi_{\mu}| <\sim \pi/6$) order of one in the large tan$\beta$ case. This is
in contrast to the case of mSUGRA in which in the parameter space where
cancellations among various SUSY contributions to EDMs happen $|\phi_{\mu}|$
must be less than $\pi/10$ for small $tan\beta$ and ${\cal{O}}(10^{-2})$ for
large $tan\beta$. Direct CP asymmetries and the T-odd polarization of lepton in
$B\to X_s l^+l^-$ are investigated in the models. In the large tan$\beta$ case,
$A_{CP}^2$ and $P_N$ for l=$\mu$ ($\tau$) can be enhanced by about a factor of
ten (ten) and ten (three) respectively compared to those of mSUGRA.


title: Chargino Pair Production at $e^+e^-$ Colliders with Polarized Beams

abstract:
  The chargino $\tilde{\chi}^\pm_{1,2}$ system can be reconstructed completely
in $e^+e^-$ collisions. By measuring the total cross sections and the
asymmetries with polarized beams in $e^+e^-\to\tilde{\chi}_i^+ \tilde{\chi}_j^-
[i,j=1,2]$, the chargino masses and the gaugino-higgsino mixing angles of these
states can be determined very accurately. If only the lightest charginos
$\tilde{\chi}_1^\pm$ are kinematically accessible, transverse beam polarization
is needed to determine the mixing angles unambiguously. From these observables
the fundamental SUSY parameters can be derived: the SU(2) gaugino mass $M_2$,
the modulus and the cosine of the CP-violating phase of the higgsino mass
parameter $\mu$, and $\tan\beta = v_2/v_1$, the ratio of the vacuum expectation
values of the two neutral Higgs doublet fields. [The remaining two-fold
ambiguity of the phase can be resolved by measuring the normal polarization of
the charginos.]


title:
The Influence of Multiplicity Fluctuation on the Erraticity Behaviour in
  High Energy Collisions

abstract:
  The influence of multiplicity distribution (fluctuation of multiplicity in
the event space) on the erraticity behaviour in high energy collisions is
investigated via Monte Carlo simulation and compared with the experimental
results from NA27 data. It is shown that, the erraticity phenomenon is
insensitive to the multiplicity fluctuation. When the average multiplicity is
low, this phenomenon is dominated by the statistical fluctuations also in the
case of multiplicities, fluctuating from event to event.


title: Out-of-equilibrium dynamics of large-N \phi^4 QFT in finite volume

abstract:
  The $\lambda \phi^4$ model in a finite volume is studied in the infinite $N$
limit both at equilibrium and out of equilibrium, with particular attention to
certain fundamental features of the broken symmetry phase. The numerical
solution of the dynamical evolution equations shows that the zero-mode quantum
fluctuations cannot grow macroscopically large starting from microscopic
initial conditions. Thus we conclude that there is no evidence for a dynamical
Bose-Einstein condensation, in the usual sense. On the other hand, out of
equilibrium the long-wavelength fluctuations do scale with the linear size of
the system, signalling dynamical infrared properties quite different from the
equilibrium ones characteristic of the same approximation scheme.


title: An improved time-dependent Hartree-Fock approach for scalar \phi^4 QFT

abstract:
  The $\lambda \phi^4$ model in a finite volume is studied within a
non-gaussian Hartree-Fock approximation (tdHF) both at equilibrium and out of
equilibrium, with particular attention to the structure of the ground state and
of certain dynamical features in the broken symmetry phase. The mean-field
coupled time-dependent Schroedinger equations for the modes of the scalar field
are derived and the suitable procedure to renormalize them is outlined. A
further controlled gaussian approximation of our tdHF approach is used in order
to study the dynamical evolution of the system from non-equilibrium initial
conditions characterized by a uniform condensate. We find that, during the slow
rolling down, the long-wavelength quantum fluctuations do not grow to a
macroscopic size but do scale with the linear size of the system, in accordance
with similar results valid for the large $N$ approximation of the O(N) model.
This behavior undermines in a precise way the gaussian approximation within our
tdHF approach, which therefore appears as a viable mean to correct an unlikely
feature of the standard HF factorization scheme, such as the so-called
``stopping at the spinodal line'' of the quantum fluctuations. We also study
the dynamics of the system in infinite volume with particular attention to the
asymptotic evolution in the broken symmetry phase. We are able to show that the
fixed points of the evolution cover at most the classically metastable part of
the static effective potential.


title: Updated Bounds on Milli-Charged Particles

abstract:
  We update the bounds on fermions with electric charge $\epsilon e$ and mass
$m_\epsilon$. For $m_\epsilon\lsim m_e$ we find $10^{-15}\lsim\epsilon<1$ is
excluded by laboratory experiments, astrophysics and cosmology. For larger
masses, the limits are less restrictive and depend on $m_\epsilon$. For
milli-charged neutrinos, the limits are stronger, especially if the different
flavors mix as suggested by current experimental evidence.


title: The QCD pomeron at TESLA - motivation and exclusive J/psi production

abstract:
  We briefly present the motivation for studying the processes mediated by the
QCD pomeron at high energy e+e- colliders. We describe the behaviour of the
cross-section for the reaction gamma gamma to J/psi J/psi obtained from the
BFKL equation with dominant non-leading corrections. We give the predictions
for the rates of anti-tagged e+e- to e+e- J/psi J/psi events in TESLA and
conclude that such reactions may be excellent probes of the hard pomeron.


title: Stabilizing Textures in 3+1 Dimensions with Semilocality

abstract:
  It is shown that textures in 3+1 dimensions can be stabilized by partial
gauging (semilocality) of the vacuum manifold such that topological unwinding
by a gauge transformation is not possible. This introduction of gauge fields
can be used to evade Derrick's theorem without higher powers of derivatives and
prevent the usual collapse of textures by the effective `pressure' terms
induced by the gauge fields. A virial theorem is derived and shown to be a
manifestation of the stability of the configuration towards collapse.


title: Production of fermions in models of string cosmology

abstract:
  Production of spin 1/2 fermions and gravitinos by the standard mechanism of
amplification of quantum fluctuations during the dilaton-driven inflation phase
in models of string cosmology is highly suppressed. Constraints on string
cosmology models from gravitational production of gravitinos, contrary to
expectations, are similar to constraints on other models.


title: Low Energy Hadron Physics

abstract:
  Ask a group of particle theorists about low energy hadron physics and they
will say that this is a subject that belongs to the age of the dinosaurs.
  However, it is GeV physics that controls the outcome of every hadronic
interaction at almost every energy. Confinement of quarks and gluons (and any
other super-constituents) means that it is the femto-universe that determines
what experiments detect.
  What we have to learn at the start of the 21st century is discussed.


title:
Local Finite Density Theory, Statistical Blocking and Color
  Superconductivity

abstract:
  The motivation for the development of a local finite density theory is
discussed. One of the problems related to an instability in the baryon number
fluctuation of the chiral symmetry breaking phase of the quark system in the
local theory is shown to exist. Such an instability problem is removed by
taking into account the statistical blocking effects for the quark propagator,
which depends on a macroscopic {\em statistical blocking parameter} $\epsilon$.
This new frame work is then applied to study color superconducting phase of the
light quark system.


title:
Effects of Bose-Einstein Condensation on forces among bodies sitting in
  a boson heat bath

abstract:
  We explore the consequences of Bose-Einstein condensation on
two-scalar-exchange mediated forces among bodies that sit in a boson gas. We
find that below the condensation temperature the range of the forces becomes
infinite while it is finite at temperatures above condensation.


title: Models of Neutrino Mass and Mixing

abstract:
  There are two basic theoretical approaches to obtaining neutrino mass and
mixing. In the minimalist approach, one adds just enough new stuff to the
Minimal Standard Model to get $m_\nu \neq 0$ and $U_{\alpha i} \neq 1$. In the
holistic approach, one uses a general framework or principle to enlarge the
Minimal Standard Model such that, among other things, $m_\nu \neq 0$ and
$U_{\alpha i} \neq 1$. In both cases, there are important side effects besides
neutrino oscillations. I discuss a number of examples, including the
possibility of leptogenesis from R parity nonconservation in supersymmetry.


title: Polarization of Inclusive $\Lambda_c$'s in a Hybrid Model

abstract:
  A hybrid model is presented for hyperon polarization that is based on
perturbative QCD subprocesses and the recombination of polarized quarks with
scalar diquarks. The updated hybrid model is applied to $p+p\to \Lambda +X$ and
successfully reproduces the detailed kinematic dependence shown by the data.
The hybrid model is extended to include pion beams and polarized $\Lambda_c$'s.
The resulting polarization is found to be in fair agreement with recent
experiments. Predictions for the polarization dependence on $x_F$ and $p_T$ is
given.


title:
Contributions of order ${\cal O}(m_{\rm quark}^2)$ to $K_{\ell 3}$ form
  factors and unitarity of the CKM matrix

abstract:
  The form factors for the $K_{\ell 3}$ semileptonic decay are computed to
order $O(p^4)$ in generalized chiral perturbation theory. The main difference
with the standard $O(p^4)$ expressions consists in contributions quadratic in
quark masses, which are described by a single divergence-free low-energy
constant, $A_3$. A new simultaneous analysis is presented for the CKM matrix
element $V_{us}$, the ratio $F_K/F_{\pi}$, $K_{\ell 3}$ decay rates and the
scalar form factor slope $\lambda_0$. This framework easily accommodates the
precise value for $V_{ud}$ deduced from superallowed nuclear $\beta$-decays.


title: Toward the non-perturbative description of high energy processes

abstract:
  General implications of existence of non-perturbative scales and hadronic
sub-structure for high energy processes are discussed. We propose that the
dependence of the cross section of $\bar q q$ dipoles on their size d should
deviate from $d^2$ when d becomes comparable to substructure scale. Then we
discuss Kharzeev-Levin pomeron model \cite{KL}, based on ladder-type diagrams
with $scalar$ resonances (scalar $\pi\pi$ or $\sigma$ and the scalar glueball
$G_0$). This channel is truly unique, because instanton-induced attractive gg
interaction \cite{Shu_82} leads to unusually small sizes and strong coupling
constants of these states, supplemented by unusually large mass scale,
$M_0\approx 4 GeV$, of the transition boundary to the perturbative regime. As
pomeron is a small-size object by itself, these resonances may play a special
role in its dynamics. Furthermore, we use more realistic description of the
scalar gluonic spectral density without free parameters, and slightly modify
the model to get correct chiral limit. We conclude that the non-perturbative
part of the scalar contribution to the soft pomeron intercept is $\Delta =
>.05\pm 0.015$, with comparable contributions from both $\sigma$ and $G_0$.


title: Longitudinal Spin Dependence of Massive Lepton Pair Production

abstract:
  We show that massive lepton-pair production, the Drell-Yan process, should be
a good source of independent constraints on the polarized gluon density, free
from the experimental and theoretical complications of photon isolation that
beset studies of prompt photon production. We provide predictions for the
spin-averaged and spin-dependent differential cross sections as a function of
transverse momentum $Q_T$ at energies relevant for the Relativistic Heavy Ion
Collider (RHIC) at Brookhaven.


title:
Comment on "Calculation of the Quarkonium Spectrum and m(b), m(c) to
  Order alpha(s)**4"

abstract:
  A recent determination of the mass of the b quark, based exclusively on
quantum chromodynamics (by avoiding strictly to introduce any phenomenological
interaction potential of nonperturbative origin), may be improved by allowing
for a merely numerical solution of the corresponding eigenvalue problem.


title:
Equivalence of Recurrence Relations for Feynman Integrals with the Same
  Total Number of External and Loop Momenta

abstract:
  We show that the problem of solving recurrence relations for L-loop
(R+1)-point Feynman integrals within the method of integration by parts is
equivalent to the corresponding problem for (L+R)-loop vacuum or (L+R-1)-loop
propagator-type integrals. Using this property we solve recurrence relations
for two-loop massless vertex diagrams, with arbitrary numerators and integer
powers of propagators in the case when two legs are on the light cone, by
reducing the problem to the well-known solution of the corresponding recurrence
relations for massless three-loop propagator diagrams with specific boundary
conditions.


title: Testing Nonperturbative Ansaetze for the QCD Field Strength Correlator

abstract:
  A test for the Gaussian and exponential Ansaetze for the nonperturbative
parts of the coefficient functions, D^{nonpert.} and D_1^{nonpert.}, which
parametrize the gauge-invariant bilocal correlator of the field strength
tensors in the stochastic vacuum model of QCD, is proposed. It is based on the
evaluation of the heavy-quark condensate within this model by making use of the
world-line formalism and equating the obtained result to the one following
directly from the QCD Lagrangian. This yields a certain relation between
D^{nonpert.}(0) and D_1^{nonpert.}(0), which is further compared with an
analogous relation between these quantities known from the existing lattice
data. Such a comparison leads to the conclusion that at the distances smaller
than the correlation length of the vacuum, Gaussian Ansatz is more suitable
than the exponential one.


title:
The triple Higgs self-coupling at future e+e- colliders: a
  signal-to-background study for the standard model

abstract:
  The experimental reconstruction of the Higgs self-energy potential is
essential to a verification of the Higgs boson's role in spontaneous
electroweak symmetry breaking. The first step towards this goal, the
measurement of the triple Higgs self-coupling, can possibly be accomplished at
the next generation of linear colliders. Here we present a background study of
the most promising channel, double Higgs-strahlung off a Z boson, e+e- -> HHZ,
with the subsequent decay H -> b bbar, and evaluate the feasibility of its
measurement.


title:
Diffractive Lambda_c^+ Productions in Polarized pp Reactions and
  Polarized Gluon Distribution

abstract:
  To test the model of the polarized gluon distribution $\Delta G(x, Q^2)$ in
the proton, we propose a new process, diffractive $\Lambda_c^+$ productions in
polarized $pp$ reactions, which will be observed in the forthcoming RHIC and
also the proposed HERA-$\vec {\rm N}$ experiments. The spin correlation between
the target proton and the $\Lambda_c^+$ produced in the target fragmentation
region largely depends on $\Delta G(x, Q^2)$ and thus, the process is quite
promising for testing the models of $\Delta G(x, Q^2)$.


title:
Azimuthal Spin Asymmetries in Semi-Inclusive Production from
  Positron-Proton Scattering

abstract:
  The recent measurements of azimuthal single spin asymmetries by the HERMES
collaboration at DESY may shed some light on presently unknown fragmentation
and distribution functions. We present a study of such functions and give some
estimates of weighted integrals directly related to those measurements.


title: Fluctuations and Phase Transition Dynamics

abstract:
  Kibble and Zurek have provided a unifying causal picture for the appearance
of classical defects like cosmic strings or vortices at the onset of phase
transitions in relativistic QFT and condensed matter systems respectively. In
condensed matter the predictions are partially supported by agreement with
experiments in superfluid helium. We provide an alternative picture for the
initial appearance of defects that supports the experimental evidence. When the
original predictions fail, this is understood, in part, as a consequence of
thermal fluctuations (noise), which play a comparable role in both condensed
matter and QFT.


title: A Hamiltonian model for multiple production in hadron-hadron collisions

abstract:
  A Hamiltonian eikonal model for the multiple production in high energy hadron
hadron collisions is presented and worked out in the aim of providing a simple
frame for many different observables of these processes. The Hamiltonian
formulation ensures that it has the unitarity built in by construction and the
eikonal approximation makes easier the discussion of the possible spacial
inhomogeneities of the hadrons. The experimental data which are examined are
the inelastic cross section and the single and double inclusive cross sections.


title: Cosmological Aspects of Heterotic M-theory

abstract:
  In this talk we discuss a few relevant aspects of heterotic M-theory. These
are the stabilization of the two relevant moduli (the length of the eleventh
segment (pi rho) and the volume of the internal six manifold (V)) in models
where supersymmetry is broken by multiple gaugino condensation and
non-perturbative corrections to the Kahler potential; the existence of almost
flat directions in the scalar potential; the possibility of lifting them, and
their role in constructing a viable model of inflation. Finally, we review the
status of the moduli problem within these models. T


title: B Meson Transitions into Higher Mass Charmed Resonances

abstract:
  We use QCD sum rules to estimate the universal form factors describing the
semileptonic B decays into excited charmed resonances, such as the $1^-$ and
$2^-$ states $D_1^{*}$ and $D_2^{*}$ belonging to the $s_\ell^P={3/2}^-$ heavy
quark doublet, and the $2^-$ and $3^-$ states $D_2^{*\prime}$ and $D_3$
belonging to the $s_\ell^P={5\2}^-$ doublet.


title: Top Polarization at a mu+mu- Collider

abstract:
  The top quark pairs produced at a polarized muon collider are in a (nearly)
pure spin configuration. This result holds for all center-of-mass energies, and
is insensitive to the next-to-leading order QCD radiative corrections. The
decay products of a polarized top quark show strong angular correlations. We
describe an interesting interference effect between the left-handed and
longitudinally polarized W bosons in top quark decay. This effect is easily
observable in the angular distribution of the charged lepton with respect to
the beam axis.


title: Equilibration of the Gluon-Minijet Plasma at RHIC and LHC

abstract:
  We study the production and equilibration of the gluon-minijet plasma
expected to be formed in the central region of ultrarelativistic heavy-ion
collisions at the BNL-RHIC and the CERN-LHC by solving a self-consistent
relativistic transport equation. We compute the minijet production within
perturbative QCD. Subsequent collisions among the semi-hard partons are treated
by considering the elastic gg -> gg processes with screening of the long
wavelength modes taken into account. We determine the time $\tau_{eq}$ where
close to ideal hydrodynamic flow sets in, and find rather similar numbers for
central heavy-ion collisions at BNL-RHIC and CERN-LHC energies. The number
densities, energy densities and temperatures of the minijet plasma are found to
be different at RHIC and LHC, e.g. $T(\tau_{eq})\sim220$ MeV and 380 MeV,
respectively.


title: The Nucleon Sigma Term from Threshold Parameters

abstract:
  A new sum rule determines the nucleon sigma term by the \pi N elastic
scattering threshold parameters alone. This "threshold" value of \sigma(2\mu^2)
provides an independent check of existing values obtained from global
dispersive analyses, and also provides a realistic error assignment. Employing
a recent analysis of low energy (T_\pi < 100 MeV) \pi N data our sum rule
implies \sigma(2\mu^2) = 71\pm 9 MeV.


title:
Flavor Changing Effects in Theories with a Heavy Z' Boson with Family
  Non-Universal Couplings

abstract:
  There are theoretical and phenomenological motivations that there may exist
additional heavy Z' bosons with family non-universal couplings. Flavor mixing
in the quark and lepton sectors will then lead to flavor changing couplings of
the heavy Z', and also of the ordinary Z when Z-Z' mixing is included. The
general formalism of such effects is described, and applications are made to a
variety of flavor changing and CP-violating tree and loop processes. Results
are described for three specific cases motivated by a specific heterotic string
model and by phenomenological considerations, including cases in which all
three families have different couplings, and those in which the first two
families, but not the third, have the same couplings. Even within a specific
theory the results are model dependent because of unknown quark and lepton
mixing matrices. However, assuming that typical mixings are comparable to the
CKM matrix, processes such as coherent mu-e conversion in a muonic atom,
K^0-\Bar{K}^0 and B-\Bar{B} mixing, epsilon, and epsilon'/epsilon lead to
significant constraints on Z' bosons in the theoretically and
phenomenologically motivated range M_{Z'} \sim 1 TeV.


title: The Ginzburg regime and its effects on topological defect formation

abstract:
  The Ginzburg temperature has historically been proposed as the energy scale
of formation of topological defects at a second order symmetry breaking phase
transition. More recently alternative proposals which compute the time of
formation of defects from the critical dynamics of the system, have been
gaining both theoretical and experimental support. We investigate, using a
canonical model for string formation, how these two pictures compare. In
particular we show that prolonged exposure of a critical field configuration to
the Ginzburg regime results in no substantial suppression of the final density
of defects formed. These results dismiss the recently proposed role of the
Ginzburg regime in explaining the absence of topological defects in 4He
pressure quench experiments.


title:
On the Mass and Width of the Z-boson and Other Relativistic Quasistable
  Particles

abstract:
  The ambiguity in the definition for the mass and width of relativistic
resonances is discussed, in particular for the case of the Z-boson. This
ambiguity can be removed by requiring that a resonance's width $\Gamma$
(defined by a Breit-Wigner lineshape) and lifetime $\tau$ (defined by the
exponential law) always and exactly fulfill the relation $\Gamma = \hbar/\tau$.
To justify this one needs relativistic Gamow vectors which in turn define the
resonance's mass M_R as the real part of the square root $\rm{Re}\sqrt{s_R}$ of
the S-matrix pole position s_R. For the Z-boson this means that $M_R \approx
M_Z - 26{MeV}$ and $\Gamma_R \approx \Gamma_Z-1.2{MeV}$ where M_Z and
$\Gamma_Z$ are the values reported in the particle data tables.


title: CP Violating Phases and the Dark Matter Problem

abstract:
  New CP violating phases in the MSSM can affect both the abundance and
detection of neutralino dark matter. We discuss the effect of including
cosmological constraints in the limits on new sources of CP violation in the
MSSM and the effects of new CP violating parameters on dark matter densities
and detection.


title: CP Violation with Three Oscillating Neutrino Flavours

abstract:
  We explore the prospects of observing leptonic CP violation in a neutrino
factory in the context of a scenario with three strongly oscillating neutrinos
able to account for the solar, the atmospheric and the LSND results. We address
also the problems related with the fake asymmetries induced by the experimental
device and by the presence of matter.


title: Anomalous f_1 exchange in vector meson photoproduction asymmetries

abstract:
  We perform an analysis of the elastic production of vector mesons with
polarized photon beams at high energy in order to investigate the validity of a
recently proposed dynamical mechanism based on the dominance of the f_1
trajectory at large momentum transfer. The density matrix characterizing the
angular distributions of the vector meson decays is calculated within an
exchange model which includes the Pomeron and the f_1. The asymmetries of these
decays turn out to be very useful to disentangle the role of these exchanges
since their effect depends crucially on their quantum numbers which are
different. The observables analyzed are accessible with present experimental
facilities.


title: Mass Shift of Axion in Magnetic Field

abstract:
  A mass-shift of the axion propagating in an external constant homogenious
magnetic field is calculated. The contributions via an electron loop and a
virtual photon are examined. It is shown that the virtual photon contribution
dominates substantially over the electron-loop one. Under the conditions of the
early Universe the electron-loop contribution to the massless axion mass-shift
is equal to zero while the virtual photon contribution is finite and can be of
order of the recent restrictions on the axion mass.


title: On Color Superconductivity in External Magnetic Field

abstract:
  We study color superconductivity in external magnetic field. We discuss the
reason why the mixing angles in color-flavor locked (CFL) and two-flavor
superconductivity (2SC) phases are different despite the fact that the CFL gap
goes to the 2SC gap for $m_s \to \infty$. Although flavor symmetry is
explicitly broken in external magnetic field, we show that all values of gaps
in their coset spaces of possible solutions in the CFL phase are equivalent in
external magnetic field.


title: Single-W Production and Fermion-Loop Scheme: Numerical Results

abstract:
  The single-W production mechanism is synonymous to the electron-positron
annihilation into electron, neutrino and a W boson with the outgoing electron
lost in a small cone around the beam direction. It requires a Renormalization
Scheme that preserves gauge invariance and fermion masses cannot be neglected
in the calculation. A recently proposed generalization of the so-called
Fermion-Loop scheme is applied to the evaluation of observables at LEP 2
energies. Single-W processes are dominated by a regime of low momentum transfer
of the outgoing electron and any high-energy Renormalization Scheme fails to
give the correct description of the scale. The Fermion-Loop scheme
automatically converts all couplings of the theory into couplings that are
running at the appropriate scale. Therefore, in addition to represent the only
scheme fully justified on a field-theoretical basis, the Fermion-Loop is the
best starting point to include radiative corrections into single-W production.
Numerical results are presented, showing a decrease in the predictions that can
be sizeable. There is no naive and overall rescaling of the e.m. coupling
constant, in any pragmatic scheme, that can reproduce the Fermion-Loop results,
at the requested accuracy, for all configurations and for all kinematical cuts.


title:
Trends in Grand Unification: unification at strong coupling and
  composite models

abstract:
  We review several problems of conventional Grand Unification and some new
approaches. In particular, we discuss strongly coupled Grand Unified Theories.
Standard Model may emerge as a low energy effective theory of composite
particles in these models. We construct a realistic model of this kind.


title: How Could the Proton Transversity be Measured

abstract:
  The perspectives of two new nonstandard methods of transversal quark
polarization measurement are considered: the jet handedness and the so-called
"Collins effect" due to spin dependent T-odd fragmentation function responsible
for the left-right asymmetry in fragmenting of transversally polarized quarks.
Recent experimental indications in favor of these effects are observed: 1.The
correlation of the T-odd one-particle fragmentation functions found by DELPHI
in $Z\to 2$-jet decay. Integrated over the fraction of longitudinal and
transversal momenta, this correlation is of 1.6% order, which means order of
13% for the analyzing power. 2.A rather large ($\approx10%$) handedness
transversal to the production plane observed in the diffractive production of
($\pi^-\pi^+\pi^-$) triples from nuclei by the $40 {\rm GeV/c}$ $\pi^-$--beam.
It shows a clear dynamic origin and resembles the single spin asymmetry
behavior.
  All this makes us hope to use these effects in polarized DIS experiments for
transversity measurement. The first estimation of transversity was done by
using the azimuthal asymmetry in semi-inclusive DIS recently measured by HERMES
and SMC.


title:
Z' indication from new APV data in Cesium and searches at linear
  colliders

abstract:
  New data on parity violation in atomic cesium can be explained by a new
neutral vector boson almost unmixed with Z, with a mass in the TeV range and
sizeable couplings to the fermions. The properties of such additional Z' can be
investigated at future linear colliders.


title: Sphaleron rate in the symmetric electroweak phase

abstract:
  Recently Bodeker has presented an effective infrared theory for the dynamics
of Yang-Mills theory, suitable for studying the rate of baryon number violation
in the early universe. We extend his theory to include Higgs fields, and study
how much the Higgs affects the baryon number violation rate in the symmetric
phase, at the phase coexistence temperature of a first order electroweak phase
transition. The rate is about 20% smaller than in pure Yang-Mills theory. We
also analyze the sphaleron rate in the analytic crossover regime. Our treatment
relies on the ergodicity conjecture for 3-D scalar $\phi^4$ theory.


title:
Relativistic Charge Form Factor of the Deuteron from (np)-Scattering
  Phase Shifts

abstract:
  Relativistic integral representation in terms of experimental neutron-proton
scattering phase shifts is used to compute the charge form factor of the
deuteron $ G_{Cd}(Q^2)$. The results of numerical calculations of
$|G_{Cd}(Q^2)|$ are presented in the interval of the four-momentum transfers
squared $0 \leq Q^2 \leq 35 fm^{-2}$. Zero and the prominent secondary maximum
in $|G_{Cd}(Q^2)|$ are the direct consequences of the change of sign in the
experimental $^3S_1 $- phase shifts. Till the point $Q^2 \simeq 20 fm^{-2}$ the
calculated total relativistic correction to $|G_{Cd}(Q^2)|$ is positive and
reaches the maximal value of 25% at $Q^2 \simeq 14 fm^{-2}$.


title:
On the structure of large N cancellations in baryon chiral perturbation
  theory

abstract:
  We show how to compute loop graphs in heavy baryon chiral perturbation theory
including the full functional dependence on the ratio of the Delta--nucleon
mass difference to the pion mass, while at the same time automatically
incorporating the 1/N cancellations that follow from the large-N spin-flavor
symmetry of baryons in QCD. The one-loop renormalization of the baryon axial
vector current is studied to demonstrate the procedure. A new cancellation is
identified in the one-loop contribution to the baryon axial vector current. We
show that loop corrections to the axial vector currents are exceptionally
sensitive to deviations of the ratios of baryon-pion axial couplings from SU(6)
values.


title: A D-moduli problem?

abstract:
  We point out a generic problem in string-inspired supergravity models with an
anomalous $U(1)_X$. A large number of matter multiplets charged under $U(1)_X$
remain massless above the supersymmetry-breaking scale because of degeneracy of
vacua solving the D-flatness conditions. A toy model is analyzed as an
illustration of the mechanism; we find the surprising result that many scalars
remain massless after supersymmetry-breaking in a hidden sector.


title: On the structure of systematic perturbation theory with unstable fields

abstract:
  Discussed is the structure of non-trivial counterterms that occur in the
systematic gauge-invariant perturbation theory with unstable fields introduced
in [hep-ph/9802307].