title:
Reducing model dependence of spectator effects in inclusive decays of
  heavy baryons

abstract:
  The dependence of inclusive weak decay rates of heavy hadrons on light
spectator quarks is considered. The analysis of a previous work on relating the
effects in b baryons to those in charmed baryons is extended to explicit
evaluation of the matrix elements of certain four-quark operators over heavy
baryons. It is shown that the usually postulated color antisymmetry of these
matrix elements is significantly broken. The flavor-singlet shift of inclusive
decay rates of b baryons due to the spectator effects is shown to be strongly
suppressed in the leading-log approximation. Combined with the results for the
flavor non-singlet splittings, this observation allows to argue, in a less
model-dependent way, than before, that within the present understanding of the
spectator effects it is highly unlikely that the lifetimes of the Lambda_b and
the B_d can be split by more than 10%.


title: Hard Exclusive and Diffractive Processes in QCD

abstract:
  Exclusive and semi-exclusive processes, the diffractive dissociation of
hadrons into jets, and hard diffractive processes such as vector meson
leptoproduction provide new testing grounds for QCD and essential information
on the structure of light-cone wavefunctions of hadrons, particularly the pion
distribution amplitude. I review the basic features of the leading-twist QCD
predictions and the problems and challenges of studying QCD at the amplitude
level. The application of the light-cone formalism to the exclusive
semi-leptonic decay of heavy hadrons is also discussed.


title: Heavy Higgs Productions at $\gamma \gamma$ Colliders

abstract:
  Multi-Higgs doublet models include more than one neutral Higgs bosons, some
of which have different properties under a CP transformation. We examine their
productions at $\gamma \gamma$ colliders. It is found that helicity
observations of final top-pairs can be powerful tools to distinguish their CP
properties, especially when masses of the Higgs bosons are almost degenerate.


title:
Power corrections and resummation of radiative corrections in the single
  dressed gluon approximation - the average thrust as a case study

abstract:
  Infrared power corrections for Minkowskian QCD observables are analyzed in
the framework of renormalon resummation, motivated by analogy with the skeleton
expansion in QED and the BLM approach. Performing the ``massive gluon''
renormalon integral a renormalization scheme invariant result is obtained.
Various regularizations of the integral are studied. In particular, we compare
the infrared cutoff regularization with the standard principal value Borel sum
and show that they yield equivalent results once power terms are included. As
an example the average thrust < T > in e+e- annihilation is analyzed. We find
that a major part of the discrepancy between the known next-to-leading order
calculation and experiment can be explained by resummation of higher order
perturbative terms. This fact does not preclude the infrared finite coupling
interpretation with a substantial 1/Q power term. Fitting the regularized
perturbative sum plus a 1/Q term to experimental data yields
alpha_s^{MSbar}(M_Z) = 0.110 \pm 0.002.


title:
Interpretation of the nonextensitivity parameter $q$ in some
  applications of Tsallis statistics and L\'evy distributions

abstract:
  The nonextensitivity parameter $q$ occuring in some of the applications of
Tsallis statistics (known also as index of the corresponding L\'evy
distribution) is shown to be given, in $q>1$ case, entirely by the fluctuations
of the parameters of the usual exponential distribution.


title: Soft Thermal Loops in Scalar Quantum Electrodynamics

abstract:
  Scalar QED is used to study approximations in thermal field theory beyond the
Hard Thermal Loop resummation scheme. For this purpose the photon self energy
is calculated for external momenta of the order e^2T using Hard Thermal Loop
resummed Green functions.


title: Non-Perturbative Dilepton Production from a Quark-Gluon Plasma

abstract:
  The dilepton production rate from the quark-gluon plasma is calculated from
the imaginary part of the photon self energy using a quark propagator that
contains the gluon condensate. The low mass dilepton rate obtained in this way
exhibits interesting structures (peaks and gaps), which might be observable at
RHIC and LHC.


title:
Unified Models at Intermediate Energy Scales and Kaluza-Klein
  Excitations

abstract:
  We discuss the possibility of intermediate gauge coupling unification in
unified models of string origin. Useful relations of the \beta-function
coefficients are derived, which ensure unification of couplings when
Kaluza--Klein excitations are included above the compactification scale. We
apply this procedure to two models with SU(3)\times SU(3)_L\times SU(3)_R and
SU(4)\times O(4) gauge symmetries.


title:
Complete Renormalization Group Improvement- Avoiding Scale Dependence in
  QCD Predictions

abstract:
  We show that dimensionful renormalization scheme parameters such as the
renormalization or factorization scale can be completely eliminated from
perturbative QCD predictions provided that all the ultraviolet logarithms
involving the physical energy scale Q are completely resummed.


title: Hard Colour Singlet Exchange at the Tevatron

abstract:
  We have performed a detailed phenomenological investigation of the hard
colour singlet exchange process which is observed at the Tevatron in events
which have a large rapidity gap between outgoing jets. We include the effects
of multiple interactions to obtain a prediction for the gap survival factor.
Comparing the data on the fraction of gap events with the prediction from BFKL
pomeron exchange we find agreement provided that a constant value of alpha_s is
used in the BFKL calculation. Moreover, the value of alpha_s is in line with
that extracted from measurements made at HERA.


title: Constraints on Neutrino Mixing

abstract:
  We explore the implications of imposing the constraint that two neutrino
flavors (which for definiteness we take to be the mu and tau neutrinos) are
similarly coupled to the mass basis in addition to the unitarity constraints.
We allow three active and an arbitrary number of sterile neutrinos. We show
that in this scheme one of the mass eigenstates decouples from the problem,
reducing the dimension of the flavor space by one.


title:
Single target-spin asymmetries in semi-inclusive pion electroproduction
  on longitudinally polarized protons

abstract:
  We evaluate the single target-spin sin(phi_h) and sin(2\phi_h) azimuthal
asymmetries in the semi-inclusive deep inelastic lepton scattering off
longitudinally polarized proton target under HERMES kinematic conditions. A
good agreement with the HERMES data can be achieved using only the twist-2
distribution and fragmentation functions.


title:
Infrared divergences and non-lightlike eikonal lines in Sudakov
  processes

abstract:
  We propose a method to analyze infrared contributions to non-inclusive
processes in QCD. We use the one-loop Sudakov form factor as a working example.
Borrowing techniques from renormalization theory, we construct counterterms for
the contributions from the soft and collinear regions, and we relate them to
eikonal Wilson lines taken along non-lightlike directions.


title: Emission of Radio Waves in Gamma Ray Bursts and Axionic Boson Stars

abstract:
  We point out that the bursts of photons with the energy of the axion mass may
appear coincidentally with gamma ray bursts if the gamma ray bursts are caused
by collisions between neutron stars and axionic boson stars. In this mechanism,
jets are formed in the collisions with large Lorentz factors $\geq 10^2$. We
explain qualitatively time-dependent complex structures of gamma ray bursts as
well as the large energy problem. Therefore, with detection of the
monochromatic photons we can test the model and determine the axion mass.


title: Gravitational Lensing and Extra Dimensions

abstract:
  We study gravitational lensing and the bending of light in low energy scale
(M_S) gravity theories with extra space-time dimensions n. We find that due to
the presence of spin-2 Kaluza-Klein states from compactification, a correction
to the deflection angle with a strong quadratic dependence on the photon energy
is introduced. No deviation from the Einstein General Relativity prediction for
the deflection angle for photons grazing the Sun in the visible band with 15%
accuracy (90% c.l.) implies that the scale M_S has to be larger than
1.4(2/(n-2))^{1/4} TeV and approximately 4 TeV for n=2. This lower bound is
comparable with that from collider physics constraints. Gravitational lensing
experiments with higher energy photons can provide stronger constraints.


title: Virtual photons to fourth order CHPT with nucleons

abstract:
  I discuss the whole mechanism to calculate isospin violation effects in the
framework of CHPT. In order to get the correct size of isospin violation one
has to include all non-isospin symmetric sources like the electromagnetic
interaction, the quark mass difference ($\pi_0 - \eta$ mixing), explicit photon
loops. As examples I discuss the electromagnetic contributions to the pion
nucleon sigma term and to the S-wave pion nucleon scattering length.


title: The Quark Lepton Mass Problem and the Anti-Grand Unification Model

abstract:
  The fermion mass problem and the ideas of mass protection are briefly
reviewed. The Fritzsch ansatz for the quark mass matrices and a recent variant,
based on a lightest flavour mixing mechanism in which all the CKM mixing angles
disappear in the chiral symmetry limit of vanishing up and down quark masses,
are discussed. The Anti-Grand Unification Model (AGUT) and the Multiple Point
Principle (MPP) used to calculate the values of the Standard Model gauge
coupling constants in the theory are described. The application of the MPP to
the pure Standard Model predicts the top quark mass to be $173 \pm 5$ GeV and
the Higgs particle mass to be $135 \pm 9$ GeV. Mass protection by the chiral
quantum numbers of the maximal AGUT gauge group $SMG \times U(1)_f$ provides a
successful fit to the charged fermion mass spectrum, with an appropriate choice
of Higgs fields to break the AGUT gauge group down to the Standard Model gauge
group (SMG) close to the Planck scale. The puzzle of the neutrino masses and
mixing angles presents a challenge to the AGUT model and approaches to this
problem are briefly discussed.


title: Bose-Einstein correlations

abstract:
  The effect of Bose-Einstein correlations on multiplicity distributions of
identical pions is discussed. It is found that these correlations affect
significantly the observed multiplicity distributions, but Einstein's
condensation is unlikely to be achieved, unless "cold spots", i.e. regions,
where groups of pions with very small relative momenta are produced, occur in
high energy heavy-ion collisions.


title: Deep inelastic Scattering, QCD, and generalised vector dominance

abstract:
  We provide a formulation of generalised vector dominance (GVD) for low-x
deep-inelastic scattering that explicitly incorporates the ${\gamma}^{\ast} \to
q{\bar q}$ transition and a QCD-inspired ansatz for the $(q{\bar q})p$
forward-scattering amplitude. The destructive interference originally
introduced in off-diagonal GVD is recovered in the present formulation and
traced back to the generic structure of two-gluon-exchange as incorporated into
the notion of colour transparency. Asymptotically, the transverse
photoabsorption cross section behaves as (ln Q^2)/Q^2, implying a logarithmic
violation of scaling for F_2, while the longitudinal-to-transverse ratio
decreases as 1/ln Q^2.


title: Lattice matrix elements confronting the experimental value of eps'/eps

abstract:
  A new lattice estimate of K -> 2 pi transitions claims, contrary to all other
computations, that the hadronic matrix element for the gluon penguin operator
Q_6 has opposite sign and, in addition, is much larger than the vacuum
saturation approximation. We comment under what conditions (if any) it is
possible to reconcile this lattice result with the experimental value of
eps'/eps. The dramatic impact of new physics in the kaon system that seems to
be required is not easily accommodated within our present theoretical
understanding.


title: Pion Properties in the 1/N_c-corrected NJL model

abstract:
  We investigate the effect of mesonic fluctuations on the pion propagator in
the Nambu-Jona-Lasinio (NJL) model by explicitly taking into account 1/N_c
corrections. Because of the non-renormalizability of the model we have to
regularize the meson loops with an independent cutoff parameter Lambda_M.
Whereas for moderate values of Lambda_M the pion properties change only
quantitatively we encounter strong instabilities for larger values of Lambda_M.


title: Large or Small Angle MSW from Single Right-Handed Neutrino Dominance

abstract:
  In this talk we discuss a natural explanation of both neutrino mass
hierarchies {\it and} large neutrino mixing angles, as required by the
atmospheric neutrino data, in terms of a single right-handed neutrino giving
the dominant contribution to the 23 block of the light effective neutrino
matrix, and illustrate this mechanism in the framework of models with U(1)
family symmetries. Sub-dominant contributions from other right-handed neutrinos
are required to give small mass splittings appropriate to the MSW solution to
the solar neutrino problem. We present three explicit examples for achieving
the small angle MSW solution in the framework of U(1) family symmetry models
containing three right-handed neutrinos, which can naturally describe all quark
and lepton masses and mixing angles. In this talk we also extend the analysis
to the large angle MSW solution.


title: Helicity Flip in Diffractive DIS

abstract:
  I review new results on s-channel helicity nonconservation (SCHNC) in
diffractive DIS. I discuss how by virtue of unitarity diffractive DIS gives
rise to spin structure functions which were believed to vanish at x << 1. These
include tensor polarization of sea quarks in the deuteron, strong breaking of
the Wandzura-Wilczek relation and demise of the Burkhardt-Cottingham sum rule.


title: Lepton -Neutron Bound States

abstract:
  We consider lepton-neutron (and lepton-antineutron) bound states and
resonances which appear due to spin-spin, spin-orbital interactions,neutron
polarization by muon. Our analis is also true for any system which include one
charge and one neutral particle with finite size e.g. $\pi^0\mu^{\pm}$-bound
states.We consider also cylindrically symmetric bound states and resonances of
particles with anomalous magnetic moments.


title: Sum rules for higher-twist parton distributions

abstract:
  In deep-inelastic scattering experiments, there is a general connection
between subtractions in dispersion relations, violations of sum-rules and
$\delta$-functions in parton distribution functions. It is explained why one
might expect a small violation in sum rules for the twist-3 distribution
functions $g_T(x)$ and $h_L(x)$ when the sum-rules are applied to $x\neq 0$
data only. The non-perturbative predictions are studied in the context of a
one-loop model.


title: The Recent Excitement in High-Density QCD

abstract:
  Over the past few months, the theory of QCD at high density has been advanced
considerably. It provides new perspectives on, and controlled realizations of,
confinement and chiral symmetry breaking. Here I survey the recent
developments, and suggest a few directions for future work.


title: Two analytical constraints on the $\eta$-$\eta^\prime$ mixing

abstract:
  We obtained two analytical constraints on the $\eta$-$\eta^\prime$ mixing
parameters by considering two-photon decays of $\eta$ and $\eta^\prime$ [$\eta
(\eta^\prime) \ra \gamma \gamma$], and productions of $\eta$ and $\eta^\prime$
in the $e^+ e^-$ scattering at large momentum transfer ($Q^2 \ra \infty$).
Using the data given in the PDG98 for the decay processes and recent CLEO
measurements on the meson-photon transition form factors, we estimate for the
$\eta_8$-$\eta_1$ mixing scheme the mixing angle to be $\theta=-14.5^\circ \pm
2.0^\circ$ and the ratio of the decay constants of singlet to octet to be
$f_1/f_8=1.17 \pm 0.08$. Applying our approach to the recently proposed $q
\qbar$-$s \sbar$ mixing scheme, we obtain the mixing angle to be
$\phi=39.8^\circ \pm 1.8^\circ$ and the ratio of the decay constants of
$s\sbar$ state to $q\qbar$ state to be $f_s/f_q=1.20 \pm 0.10$.


title: Higgs and Z-boson Signatures of Supersymmetry

abstract:
  In supersymmetric theories of nature the Higgsino fermionic superpartner of
the Higgs boson can arise as the lightest standard model superpartner depending
on the couplings between the Higgs and supersymmetry breaking sectors. In this
letter the production and decay of Higgsino pairs to the Goldstone fermion of
supersymmetry breaking and the Higgs boson, h, or gauge bosons, Z or $\gamma$
are considered. Relatively clean di-boson final states, hh, $h \gamma$, hZ, $Z
\gamma$, or ZZ, with a large amount of missing energy result. The latter
channels provide novel discovery modes for supersymmetry at high energy
colliders since events with Z bosons are generally rejected in supersymmetry
searches. In addition, final states with real Higgs bosons can potentially
provide efficient channels to discover and study a Higgs signal at the Fermilab
Tevatron Run II.


title: D* Production in Two-Photon Collisions

abstract:
  We calculate total and differential production rates of D* mesons in
two-photon collisions at LEP2. We include full next-to-leading order QCD
corrections, and perform an extensive study of the sensitivity of our
predictions to variations of the renormalization scale, charm mass, photonic
parton distribution set and fragmentation function. The results are compared
with recent data from LEP2.


title: Operator product expansion and analyticity

abstract:
  We discuss the current use of the operator product expansion in QCD
calculations. Treating the OPE as an expansion in inverse powers of an
energy-squared variable (with possible exponential terms added), approximating
the vacuum expectation value of the operator product by several terms and
assuming a bound on the remainder along the euclidean region, we observe how
the bound varies with increasing deflection from the euclidean ray down to the
cut (Minkowski region). We argue that the assumption that the remainder is
constant for all angles in the cut complex plane is not justified. Making
specific assumptions on the properties of the expanded function, we obtain
bounds on the remainder in explicit form and show that they are very sensitive
both to the deflection angle and to the class of functions chosen. The results
obtained are discussed in connetcion with calculations of the coupling constant
\alpha_{s} from the \tau decay.


title: Spectra and M1 Decay Widths of Heavy-Light Mesons

abstract:
  The M1 decay widths of charm and bottom mesons and their excited states are
sensitive to the relativistic aspect of the quark current operators and obtain
a significant contribution from the interaction current that is associated with
the scalar confining interaction between heavy quarks ($Q$) and light
antiquarks ($\bar q$). Consequently they provide direct evidence on the latter.
The spectra and the M1 transition widths of the $D$, $D_s$ and $B$, $B_s$
mesons and their orbital excitations are calculated here within the framework
of the Blankenbecler-Sugar equation, which allows a covariant treatment, while
retaining a formal similarity to the nonrelativistic approach. The hyperfine
interaction in the $Q\bar q$ mesons is modeled by screened gluon exchange,
which shares many features with the instanton induced interaction. The quality
of the model is tested by calculation of the spectra and M1 decay widths of
charmonium.


title: High-Energy Cross Section for e^+e^- to W^+ W^- to 4 fermions + gamma

abstract:
  A recently suggested high-energy Born-form representation of the one-loop
helicity amplitudes for e^+e^- to W^+W^- is supplemented by including W^+-
decay and hard-photon radiation. Results for the differential and the total
cross section for e^+e^- to W^+W^- to 4 fermions + gamma are given for the
high-energy region of sqrt(s) > 500 GeV.


title:
Branching Fraction Measurements of the SM Higgs with a Mass of 160 GeV
  at Future Linear \ee Colliders

abstract:
  Assuming an integrated luminosity of 500 fb$^{-1}$ and a center-of-mass
energy of 350 GeV, we examine the prospects for measuring branching fractions
of a Standard Model-like Higgs boson with a mass of 160 GeV at the future
linear \ee collider TESLA when the Higgs is produced via the Higgsstrahlung
mechanism, \ee \pfr HZ. We study in detail the precisions achievable for the
branching fractions of the Higgs into WW$^*$, ZZ$^*$ and \bb. However, the
measurement of BF(H \pfr \gaga) remains a great challence. Combined with the
expected error for the inclusive Higgsstrahlung production rate the uncertainty
for the total width of the Higgs is estimated.


title: Top Theories

abstract:
  As the most recently discovered and heaviest quark, the top presents us with
theoretical challenges. How are we to understand its properties within the
larger effort to explain the origins of electroweak and flavor symmetry
breaking ? This talk discusses some of the surprises the top quark may have in
store for us and indicates how experiment may help us pinpoint the truth about
top.


title: Hierarchical Four-Neutrino Oscillations With a Decay Option

abstract:
  We present a new and novel synthesis of all existing neutrino data regarding
the disappearance and appearance of $\nu_e$ and $\nu_\mu$. We assume four
neutrinos: $\nu_e, \nu_\mu, \nu_\tau$, as well as a heavier singlet neutrino
$\nu_s$ of a few eV. The latter may decay into a massless Goldstone boson (the
singlet Majoron) and a linear combination of the doublet antineutrinos. We
comment on how this scenario may be verified or falsified in future
experiments.


title: The Physics Case for Polarised Proton-Nucleon Scattering at HERA

abstract:
  The physics case for a possible fixed target polarized nucleon-nucleon
collision experiment at HERA is described. The experiment named HERA-N could be
realized using an internal polarized gas target in the HERA
polarized/unpolarized proton beam. A wide spectrum of nucleon spin structure
problems could be investigated and the experiment would constitute a fixed
target complement to the RHIC spin physics program with competitive statistical
accuracy.


title: Naturalness and Supersymmetry

abstract:
  Supersymmetry solves the gauge hierarchy problem of the Standard Model if the
masses of supersymmetric partners of the SM particles are close to the weak
scale. In this thesis, we argue that the supersymmetric Standard Model, while
avoiding the fine tuning in electroweak symmetry breaking, requires
unnaturalness/fine tuning in some (other) sector of the theory. For example,
Baryon and Lepton number violating operators are allowed which lead to proton
decay and flavor changing neutral currents. We study some of the constraints
from the latter in this thesis. We have to impose an R-parity for the theory to
be both natural and viable. In the absence of flavor symmetries, the
supersymmetry breaking masses for the squarks and sleptons lead to too large
flavor changing neutral currents. We show that two of the solutions to this
problem, gauge mediation of supersymmetry breaking and making the scalars of
the first two generations heavier than a few TeV, reintroduce fine tuning in
electroweak symmetry breaking. We also construct a model of low energy gauge
mediation with a non-minimal messenger sector which improves the fine tuning
and also generates required Higgs mass terms. We show that this model can be
derived from a Grand Unified Theory despite the non-minimal spectrum.


title: Perspectives of Light-Front Quantized Field Theory: Some New Results

abstract:
  Some basic topics in the light-front (LF) quantization of relativistic field
theory are reviewed. It is argued that the LF quantization is equally
appropriate as the conventional one and that they lead, assuming the micro-
causality principle, to the same physical content. This is confirmed in the
studies on the LF of the spontaneous symmetry breaking (SSB), of the degenerate
vacua in Schwinger model (SM) and Chiral SM (CSM), of the chiral boson theory,
and of the QCD in covariant gauges among others. The discussion on the LF is
more economical and more transparent. In the context of the Dyson-Wick pertur-
bation theory the relevant popagators in the front form theory are causal. The
Wick rotation can then be performed to employ the Euclidean space integrals in
momentum space. The lack of manifest covariance becomes tractable, and still
more so if we employ, as discussed in the text, the Fourier transform of the
fermionic field based on a special construction of the LF spinor. The fact that
the hyperplanes $x^{pm}=0$ constitute characteristic surfaces of the hyper-
bolic partial differential equation is found irrelevant in the quantized
theory.


title:
The Case of a WW Dynamical Scalar Resonance within a Chiral Effective
  Description of the Strongly Interacting Higgs Sector

abstract:
  We have studied the strongly interacting $W_L W_L \to W_L W_L$ I=L=0 partial
wave amplitude making use of effective chiral Lagrangians. The Higgs boson is
explicitly included and the N/D method is used to unitarize the amplitude. We
recover the chiral perturbative expansion at next to leading order for low
energies. The cases $m_H<< 4\pi v$ and $m_H>> 4 \pi v$ are considered in
detail. It is shown that in the latter situation a state appears with a mass
$\lesssim 1$ TeV. This state is dynamically generated through the strong
interactions between the $W_L$ and is not responsible for the spontaneous
electroweak symmetry breaking. However, its shape can be very similar to that
of the $m_H\lesssim 1$ TeV case, which corresponds to a conventional heavy
Higgs boson.


title: A Non-Perturbative Chiral Approach for Meson-Meson Interactions

abstract:
  A non-perturbative method which combines constraints from chiral symmetry
breaking and coupled channel unitarity is used to describe meson-meson
interactions up to \sqrt{s}\lesssim 1.2 GeV, extending in this way the range of
applicability of the information contained in Chiral Perturbation Theory (\chi
PT), since this perturbative series is typically restricted to \sqrt{s}\lesssim
500 MeV. The approach uses the O(p^2) and O(p^4) \chiPT Lagrangians. The seven
free parameters resulting from the O(p^4) Lagrangian are fitted to the
experimental data. The approach makes use of the expansion of T^{-1} instead of
the amplitude itself as done in \chiPT. The former expansion is suggested by
analogy with the effective range approximation in Quantum Mechanics and it
appears to be very useful. The results, in fact, are in good agreement with a
vast amount of experimental analyses.


title:
Two Meson Scattering Amplitudes and their Resonances from Chiral
  Symmetry and the N/D Method

abstract:
  We study the vector and scalar meson-meson amplitudes up to \sqrt{s}\lesssim
1.4 GeV and their associated spectroscopy. The study has been done considering
jointly the N/D method, Chiral Symmetry and implications from large N_c QCD.
The N/D method provides us with the way to unitarize the tree level amplitudes
constructed in agreement with Chiral Symmetry and its breaking (explicit and
spontaneous). These amplitudes are calculated making use of the lowest order
Chiral Perturbation Theory (\chiPT) Lagrangians and the exchanges of resonances
compatible with Chiral Symmetry as given in. On the other hand the large N_c
considerations allow us to distinguish between elementary (as elementary as the
pions, for instance) and compound (meson-meson) states. Making use of this
formalism one observes that the \sigma, \kappa and a_0(980) resonances are
meson-meson states originating from the unitarization of the lowest order
\chiPT amplitudes. On the other hand, the f_0(980) is a combination of a strong
S-wave meson-meson unitarity effect and of a preexisting singlet resonance with
a mass around 1 GeV.


title: SU(3) Chiral approach to meson and baryon dynamics

abstract:
  We report on recent progress on the chiral unitary approach, which is shown
to have a much larger convergence radius than ordinary chiral perturbation
theory, allowing one to reproduce data for meson meson interaction up to 1.2
GeV and meson baryon interaction up to the first baryonic resonances.
Applications to physical processes so far unsuited for a standard chiral
perturbative approach are presented, concretely the K^- p\to\Lambda(1405)\gamma
reaction and the N^\ast (1535)N^\ast(1535)\pi and \eta couplings.


title:
CCFM prediction on forward jets and $F_2$: parton level predictions and
  a new hadron level Monte Carlo generator CASCADE

abstract:
  A solution of the CCFM equation for a description of both the structure
function $F_2$ and the cross section of forward jet production as measured by
the HERA experiments is obtained on the basis of the parton level Monte Carlo
program SMALLX. The treatment of the non - Sudakov form factor and the so -
called "consistency constraint" are discussed. Following this a backward
evolution scheme according to CCFM is developed which then is used to construct
an efficient hadron level Monte Carlo program CASCADE. The results from the
forward evolution and the backward evolution Monte Carlos are compared and
found to be consistent.


title: Hyperon Nonleptonic Decays in Chiral Perturbation Theory Reexamined

abstract:
  We recalculate the leading nonanalytic contributions to the amplitudes for
hyperon nonleptonic decays in chiral perturbation theory. Our results partially
disagree with those calculated before, and include new terms previously omitted
in the P-wave amplitudes. Although these modifications are numerically
significant, they do not change the well-known fact that good agreement with
experiment cannot be simultaneously achieved using one-loop S- and P-wave
amplitudes.


title:
Flavor changing neutral current processes and the muon anomalous
  magnetic moment in the supergravity model

abstract:
  Flavor changing neutral current processes in B and K decays in the
supergravity model are revisited taking into account the recent progress of
Higgs boson search experiments at LEP. Possible deviations of B^0--$\bar{B}^0$
mixing, the CP violating K^0--$\bar{K}^0$ mixing parameter $\epsilon_K$ from
the standard model predictions are reduced significantly in a small $\tan\beta$
region due to the constraints on the SUSY parameter space imposed by the Higgs
boson search. With the present bound on the Higgs boson mass, the magnitude of
the B^0--$\bar{B}^0$ mixing amplitude can be enhanced up to 12% for $\tanb=3$
in the minimal supergravity. If we relax the strict universality of SUSY
breaking scalar masses at the GUT scale, the deviation can be 25%. We also
investigate SUSY contributions to the muon anomalous magnetic moment in the
supergravity model and show that there is a correlation with the $b \to s
\gamma$ amplitude. The SUSY contribution to $a_\mu = \frac{(g-2)_\mu}{2}$ can
be (-30 -- $+80)\times 10^{-10}$ for $\tan\beta=10$ and even larger for larger
$\tan\beta$. The improved measurement of the muon anomalous magnetic moment in
the on-going experiment at BNL will put a strong constraint on SUSY parameter
space, especially for a large $\tan\beta$ region.


title: Summary: Spin Physics

abstract:
  The spin physics parallel sessions at this workshop made a critical review of
the physics potential of future experiments on polarized nucleons, with an
emphasis on the potential impact of polarized electron-proton collisions at
HERA. A summary of the results and discussions from these sessions is presented
in this article.


title: Soft Perturbative QCD

abstract:
  There are indications of a faith transition in QCD: The strong coupling may
freeze at a sufficiently low value to make PQCD relevant even in the confining
regime. The properties of PQCD at low Q^2 depend on the asymptotic field
configuration assumed at t=\pm\infty. A change in the i\epsilon prescription of
the free propagators is equivalent to including quarks and gluons in the
initial and final states. Perturbative expansions thus generated are formally
as justified as standard PQCD and may turn out to be phenomenologically
relevant. I discuss examples of the effects of such propagator modifications in
QED and QCD.


title: On the perturbative approach to the penguin-induced B -> pi phi decay

abstract:
  Using a modified perturbative approach that includes the Sudakov resummation
and transverse degrees of freedom we analyze the penguin-induced B -> pi phi
decay. The perturbative method enables us to include nonfactorizable
contributions and to control virtual momenta appearing in the process. The
calculation supports the results obtained in the standard BSW factorization
approach, illustrating the electroweak penguin dominance and the branching
ratio of order O(10^{-8}). However, the estimated prediction of 16% for CP
asymmetry is much larger than that obtained in the factorization approach.


title: Nonperturbative effects in the proton sea

abstract:
  We revisit the evaluation of the pionic mechanism of the
$\bar{u}-\bar{d}$-asymmetry in the proton structure function. Our analysis is
based on the unitarity relation between contributions of different mechanisms
to the inclusive particle production and the total photoabsorption
cross-section (i.e. the proton structure function). We reanalyze the role of
isovector reggeons in inclusive production of nucleons and Delta isobars in
hadronic reactions. A rather large contribution of reggeon-exchange induced
production of Delta isobars is found. This leaves much less room for the
pion-exchange induced mechanism of $\Delta$ production and provides a
constraint on the $\pi N \Delta$ form factor. The production of leading pions
in proton-proton collisions puts additional constraints on the $\pi NN$ vertex
form factors. All these constraints are used then to estimate the pion content
of the nucleon and allow to calculate parameter-free the x-dependence of $\bar
d - \bar u$. We discuss the violation of the Gottfried Sum Rule and $\bar
d$-$\bar u$ asymmetry and compare to the one obtained from the E866 experiment
at Fermilab.


title: Constraints on Lorentz violation from clock-comparison experiments

abstract:
  Constraints from clock-comparison experiments on violations of Lorentz and
CPT symmetry are investigated in the context of a general Lorentz-violating
extension of the standard model. The experimental signals are shown to depend
on the atomic and ionic species used as clocks. Certain experiments usually
regarded as establishing comparable bounds are in this context sensitive to
different types of Lorentz violation. Some considerations relevant to possible
future measurements are presented. All these experiments are potentially
sensitive to Lorentz-violating physics at the Planck scale.


title: Asymmetrical large extra dimensions

abstract:
  We study scenarios in which there is a hierarchy of two sets of large
compactified extra dimensions. One particularly interesting case has a single
millimeter size extra dimension and five TeV^{-1} size dimensions. The Standard
Model gauge bosons have Kaluza-Klein excitations with respect to one of the TeV
scale dimensions. We discuss astrophysical constraints on this scenario, as
well as prospects for signals at future high energy colliders.


title: Classical Nambu-Goldstone fields

abstract:
  It is shown that a true Nambu-Goldstone (NG) boson develops a coherent
long-range field whenever the charge associated with it that is carried by the
other particles is not conserved in a macroscopic scale. The source of a NG
field is the time rate of quantum number violation. If the lepton numbers are
spontaneously broken at a scale below 1 TeV, the neutrino oscillation processes
generate long-range majoron fields that are strong enough in Supernovae to
modify the neutrino flavor dynamics. Two examples are given: NG fields may
improve the adiabaticity of $\nu_{e}\leftrightarrow \nu_{X}$ transitions or
cause resonant anti-neutrino oscillations otherwise impossible with solely weak
interactions.


title: Light quark distributions in the proton sea

abstract:
  We use the meson cloud model to calculate $\bar{d}(x) - \bar{u}(x)$ and $
\bar{d}(x)/\bar{u}(x)$ in the proton. We show that a modification of the
symmetric, perturbative part of the light quark sea provides better agreement
with the ratio $ \bar{d}(x)/\bar{u}(x).


title: Theta Vacua, QCD Sum Rules, and the Neutron Electric Dipole Moment

abstract:
  We present a detailed study of the electric dipole moment of the neutron
induced by a vacuum theta angle within the framework of QCD sum rules. At
next-to-next-to leading order in the operator product expansion, we find the
result d_n(\theta) = 2.4 x 10^{-16} \theta e cm, to approximately 40%
precision. With the current experimental bound this translates into a limit on
the theta parameter of |\theta| < 3 x 10^{-10}. We compare this result with the
long-standing estimates obtained within chiral perturbation theory, and observe
a numerical similarity, but also significant differences in the source of the
dominant contribution.


title:
A Quark Model Calculation of gamma gamma to pi pi Including Final State
  Interactions

abstract:
  A quark model calculation of the processes gamma gamma -> pi+ pi- and gamma
gamma -> pi0 pi0 is performed. At tree level, only charged pions couple to the
initial state photons and neutral pions are not expected in the final state.
However, a small but significant gamma gamma -> pi0 pi0 cross section is
observed. We demonstrate that this may be accounted for by a rotation in
isospin space induced by final state interactions. The resulting pi+ pi- cross
section is in good agreement with experiment while the pi0 pi0 cross section is
in qualitative agreement with the data.


title: On the PQCD prediction for the pion form factor

abstract:
  We comment on the results of a complete leading-twist next-to-leading order
QCD analysis of the spacelike pion electromagnetic form factor at
large-momentum transfer Q. For the asymptotic distribution amplitude, we have
examined the sensitivity of the predictions to the choice of the
renormalization scale. The results show that, regarding the size of the
radiative corrections, reliable perturbative predictions for the pion
electromagnetic form factor can already be made at a momentum transfer Q of the
order of 5 to 10 GeV.


title: Thinking About Top: Looking Outside The Standard Model

abstract:
  The top quark is by far the heaviest known fermion [1]. In consequence,
experiment is just beginning to explore its properties, and some of them may
yet prove to be distinctly non-standard. The very size of the top quark's mass
even hints at the possibility of a special role for top in electroweak symmetry
breaking. This talk examines the top quark in the context of physics beyond the
standard model, and discusses how Run II can help elucidate the true nature of
top.


title: A new approach to axial coupling constants in the QCD sum rule

abstract:
  We derive new QCD sum rules for the axial coupling constants by considering
two-point correlation functions of the axial-vector currents in a one nucleon
state. The QCD sum rules tell us that the axial coupling constants are
expressed by nucleon matrix elements of quark and gluon operators which are
related to the sigma terms and the moments of parton distribution functions.
The results for the iso-vector axial coupling constants and the 8th component
of the SU(3) octet are in good agreement with experiment.


title: Matter Effects in Four-Neutrino Mixing

abstract:
  We present a formalism for the description of oscillations in matter of
solar, atmospheric and long-baseline neutrinos in the two schemes of
four-neutrino mixing that are allowed by the results of all existing neutrino
oscillation experiments.


title: Gluon-Meson Duality in the Mean Field Approximation

abstract:
  In a gauge-fixed language gluon-meson duality can be described as the Higgs
mechanism for ``spontaneous symmetry breaking'' of color. We present a mean
field computation which suggests that this phenomenon is plausible in QCD. One
obtains realistic masses of the light mesons and baryons.


title: Axion model in extra dimensions with TeV scale gravity

abstract:
  A simple axion model is proposed in the scenario of large extra dimensions
where gravity scale is as low as 1 TeV. To obtain an intermediate-scale decay
constant of the axion, the axion is assumed to live in a sub-spacetime (brane)
of the whole bulk. In this model there appear Kaluza-Klein modes of the axion
which have stronger interaction than those of the graviton. The axion brane
plays a role of absorber of the graviton Kaluza-Klein modes. Because of these
reasons phenomenology and cosmology of the axion become highly non-trivial. We
discuss various cosmological constraints as well as astrophysical ones and show
that the model is viable for certain choices of the dimensionality of the axion
brane. The structure of the model proposed here provides a viable realization
of the fat brane idea to relax otherwise very severe cosmological constraints.


title: New Faces of Supersymmetry: effects of large phases on Higgs production

abstract:
  If the soft Supersymmetry (SUSY) breaking masses and couplings are complex
and cancelations do take place in the SUSY induced contributions to the
fermionic Electric Dipole Moments (EDMs), then the CP-violating soft phases can
drastically modify much of the known phenomenological pattern of the Minimal
Supersymmetric Standard Model (MSSM). In particular, the squark loop content of
the dominant Higgs production mechanism at the Large Hadron Collider (LHC), the
gluon-gluon fusion mode, could be responsible of large corrections to the known
cross sections.


title: $F_{2}^{D(4)}$ in the Model of the Stochastic Vacuum

abstract:
  In this paper a calculation for the diffractive structure functions
$F_{L}^{D(4)}$ and $F_{T}^{D(4)}$ using an eikonal approximation is presented.
A modified version of the model of the stochastic vacuum that includes an
energy dependence is used to calculate the scattering amplitude of two Wilson
loops which in our approach describe the color dipole interaction. Numerical
results are presented in the $\beta$ region where the non-perturbative effects
are expected to be large. The DIS diffractive cross section is also discussed.
Our calculation for the diffractive slope in $t$ is in good agreement with the
experiment.


title: Quintessence, Supersymmetry and Inflation

abstract:
  Recent data point in the direction of a $\Lambda$ dominated universe. We
briefly review ``Quintessence'' as a model for a dynamical cosmological term
and analyse the role of Susy QCD as a possible particle physics candidate. The
multiscalar content of the theory is fully taken into account and interaction
with other cosmological fields is discussed. Finally, the possibility of
constructing a unified scheme for quintessence and inflation is mentioned.


title:
Elastic production of Vector Mesons at HERA: study of the scale of the
  interaction and measurement of the helicity amplitudes

abstract:
  A compilation of H1 and ZEUS cross section measurements for elastic vector
meson production is presented as a function of the scale $K^2 = (Q^2+M_V^2)/4$,
where Q^2 is the exchanged photon virtuality and M_V is the mass of the vector
meson. The ratio of longitudinal to transverse cross sections R =
$\sigma_L/\sigma_T$ is presented as a function of Q^2/M^2_V. The cross sections
are separated in a transverse and a longitudinal component, and are presented
as a function of K^2. The intercept $\alpha(0)$ -- 1 governing the energy
dependence of the vector meson cross sections is compared with the $\lambda$
parameter measured in inclusive F_2 analysis. For $\rho$ meson production, the
helicity amplitude ratios $|T_{ij}|/|T_{00}|$, extracted from the H1 and ZEUS
measurements of the spin density matrix elements are presented as a function of
Q^2 and W and are compared to recent predictions.


title: B Decays, the Unitarity Triangle, and the Universe

abstract:
  A review is given of recent developments in the physics of flavor. Current
constraints on the Cabibbo-Kobayashi-Maskawa matrix are discussed and related
to the recent measurements of epsilon'/epsilon, sin(2beta) and K+ -> pi+ nu
nubar. A brief review is given of the connection between CP violation in B
decays and electroweak baryogenesis. Finally, there is an extensive discussion
of how present and proposed experiments in K and B physics can constrain the
pattern of flavor changing processes at low energies and, one hopes, eventually
provide unambiguous evidence of physics beyond the Standard Model.


title: Scalar-Tensor Gravity and Quintessence

abstract:
  Scalar fields with inverse power-law effective potentials may provide a
negative pressure component to the energy density of the universe today, as
required by cosmological observations. In order to be cosmologically relevant
today, the scalar field should have a mass
  $m_\phi = O(10^{-33} {\mathrm eV})$, thus potentially inducing sizable
violations of the equivalence principle and space-time variations of the
coupling constants. Scalar-tensor theories of gravity provide a framework for
accommodating phenomenologically acceptable ultra-light scalar fields. We
discuss non-minimally coupled scalar-tensor theories in which the scalar-matter
coupling is a dynamical quantity. Two attractor mechanisms are operative at the
same time: one towards the tracker solution, which accounts for the accelerated
expansion of the Universe, and one towards general relativity, which makes the
ultra-light scalar field phenomenologically safe today. As in usual
tracker-field models, the late-time behavior is largely independent on the
initial conditions. Strong distortions in the cosmic microwave background
anisotropy spectra as well as in the matter power spectrum are expected.


title: Real Compton Scattering from the Proton

abstract:
  Real Compton Scattering on the proton in the hard scattering regime is
investigated. Recent theoretical developments are reviewed. Plans for new
experimental studies at Jefferson Laboratory are presented.


title:
Infrared factorization of tree-level QCD amplitudes at the
  next-to-next-to-leading order and beyond

abstract:
  We study the infrared behaviour of tree-level QCD amplitudes and we derive
infrared-factorization formulae that are valid at any perturbative order. We
explicitly compute all the universal infrared factors that control the
singularities in the various soft and/or collinear limits at O(as^2).


title:
Cosmological Magnetic Fields from Gauge-Mediated Supersymmetry-Breaking
  Models

abstract:
  We study the generation of primordial magnetic fields, coherent over
cosmologically interesting scales, by gravitational creation of charged scalar
particles during the reheating period. We show that magnetic fields consistent
with those detected by observation may obtained if the particle mean life
\tau_s is in the range 10^{-14} sec \leq \tau_s \leq 10{-7} sec. We apply this
mechanism to minimal gauge mediated supersymmetry-breaking models, in the case
in which the lightest stau \tilde\tau_1 is the next-to-lightest supersymmetric
particle. We show that, for a large range of phenomenologically acceptable
values of the supersymmetry-breaking scale \sqrt{F}, the generated primordial
magnetic field can be strong enough to seed the galactic dynamo.


title:
On Neutrino-Mixing-Generated Lepton Asymmetry and the Primordial
  Helium-4 Abundance

abstract:
  In this article we discuss lepton asymmetry effect on BBN with neutrino
oscillations. We argue that asymmetry much smaller than 0.01, although not big
enough to influence directly the nucleosynthesis kinetics, can effect
considerably BBN indirectly via neutrino oscillations. Namely, it distorts
neutrino spectrum and changes neutrino density evolution and the pattern of
oscillations (either suppressing or enhancing them), which in turn effect the
primordial synthesis of elements. We show that the results of the paper X. Shi
et al., Phys. Rev. D 60, 063002 (1999), based on the assumption that only L >
0.01 will influence helium-4 production, are not valid. Instead, the precise
constraints on neutrino mixing parameters from BBN are presented.


title:
The Nucleon Spin Polarizability at Order ${\cal O}(p^4$) in Chiral
  Perturbation Theory

abstract:
  We calculate the forward spin-dependent photon-nucleon Compton amplitude as a
function of photon energy at the next-to-leading (${\cal O}(p^4)$) order in
chiral perturbation theory, from which we extract the contribution to nucleon
spin polarizability. The result shows a large correction to the leading order
contribution.


title: Introductory lecture notes on the Karabali-Nair theory

abstract:
  The Schroedinger functional treatment of 2+1 D Yang-Mills theory (related to
the magnetic mass problem of 4D hot gluons) is recapitulated by following
Karabali, Kim and Nair in Nucl. Phys. B 524 (1998) 661 (first half). The notes
include the Hermitean WZW model and end up with the lowest eigenvalue (mass
gap) of the functional kinetic energy. Let calculational details be invariant
under the (german) language used.


title: The AGL Equation from the Dipole Picture

abstract:
  The AGL equation includes all multiple pomeron exchanges in the double
logarithmic approximation (DLA) limit, leading to an unitarized gluon
distribution in the small x regime. This equation was originally obtained using
the Glauber-Mueller approach. We demonstrate in this paper that the AGL
equation and, consequently, the GLR equation, can also be obtained from the
dipole picture in the double logarithmic limit, using an evolution equation,
recently proposed, which includes all multiple pomeron exchanges in the leading
logarithmic approximation. Our conclusion is that the AGL equation is a good
candidate for an unitarized evolution equation at small x in the DLA limit.


title: Pair production of charged MSSM Higgs bosons by gluon fusion

abstract:
  The production of pairs of charged Higgs bosons as predicted by the minimal
supersymmetric standard model (MSSM) via the gluon fusion mechanism is
investigated. The amplitudes at the leading one-loop order for the parton
process gg -> H+ H- are calculated with the complete set of MSSM particles.
Numerical results are presented for the cross section of the inclusive hadron
process p p -> gg -> H+ H- + X at the LHC.


title:
Anomaly-Induced Gauge Unification and Brane/Bulk Couplings in
  Gravity-Localized Theories

abstract:
  It has recently been proposed that gravity-localized compactifications can
generate the required gauge hierarchy without the need for hierarchically large
extra spacetime dimensions. In this paper, we show that gauge coupling
unification arises naturally in such scenarios as a result of the anomaly
induced by the rescaling of the wavefunctions of the brane fields. Thus,
``anomaly-induced'' gauge coupling unification can easily explain the apparent
low-energy gauge couplings in gravity-localized compactifications. However, we
also point out a number of phenomenological difficulties with such
compactifications, including an inability to accommodate the GUT scale and the
electroweak scale simultaneously. We also show that brane/bulk couplings in
this scenario are generically too small to be phenomenologically relevant.
Finally, we speculate on possible resolutions to these puzzles.


title:
A combined study of $b \to s \gamma$ and the muon anomalous magnetic
  moment in gauge-mediated supersymmetry breaking models

abstract:
  We study both the branching ratio for $b \to s \gamma$ decay and the muon
anomalous magnetic moment, $a_{\mu} \equiv (g-2)_{\mu} /2$, in the minimal
supersymmetric standard model with gauge-mediated supersymmetry breaking.
Combining new experimental data on $a_{\mu}$ and the branching ratio for $b \to
s \gamma$, useful limits on the parameter space of these models are derived. In
particular, we explicitly show that, with the presently available experimental
data, constraints from the decay $b \to s \gamma$ are more stringent than those
from $a_{\mu}$ in broad region of the parameter space. We include the
supersymmetric one-loop correction to the mass of $b$ quark, $m_b$, and find
that in order to have a correct value of $m_b$, the region of large tan$\beta$
and $\mu <0$ (in our convention) is not allowed in these models (if there are
no further assumptions like $b - \tau$ Yukawa coupling unification). The region
of large tan$\beta$ and $\mu >0$ is also strongly constrained. We present
bounds on supersymmetric particle masses as a function of $\tan \beta$.


title: Gluonic Excitations' Millennial Finale

abstract:
  We provide an overview of theoretical developments on hybrid mesons and
glueballs in the last year at this turn of the millenium conference. Cracks in
potential models of conventional mesons are developing. Hybrid meson adiabatic
surfaces have been calculated and interpreted, experimental J^PC exotics have
hybrid meson, four-quark state or non-resonant interpretations, and the strong
decay mechanism of hybrids has been studied. All theoretical progress on hybrid
mesons in the last year is mentioned. Overall features of glueballs are
visited: decays and the successes of the large N_c limit. Two promising
experimental areas are mentioned: charmonium hybrids at B-factories and s sbar
hybrids at Jefferson Lab.


title: Additional Isospin-Breaking Effects in \epsilon^\prime/\epsilon

abstract:
  In the analysis of \epsilon^\prime/\epsilon it has been traditional to
consider the isospin-breaking effects arising from electroweak-penguin
contributions and from \pi^0-\eta and \pi^0-\eta^\prime mixing, yet additional
isospin-violating effects exist. In particular, we study the isospin violation
which arises from the u-d quark mass difference in the hadronization of the
gluonic penguin operator, engendering contributions of an effective \Delta
I=3/2 character. Using chiral perturbation theory and the factorization
approximation for the hadronic matrix elements, we find within a specific model
for the low-energy constants that we can readily accommodate an increase in
\epsilon^\prime/\epsilon by a factor of two.


title:
The initial energy density of gluons produced in very high energy
  nuclear collisions

abstract:
  In very high energy nuclear collisions, the initial energy of produced gluons
per unit area per unit rapidity, $dE/L^2/d\eta$, is equal to $f(g^2\mu L)
(g^2\mu)^3/g^2$, where $\mu^2$ is proportional to the gluon density per unit
area of the colliding nuclei. For an SU(2) gauge theory, we perform a
non--perturbative numerical computation of the function $f(g^2\mu L)$. It
decreases rapidly for small $g^2\mu L$ but varies only by $\sim 25$%, from
$0.208\pm 0.004$ to $0.257\pm 0.005$, for a wide range 35.36--296.98 in $g^2\mu
L$, including the range relevant for collisions at RHIC and LHC. Extrapolating
to SU(3), we estimate the initial energy per unit rapidity for Au-Au collisions
in the central region at RHIC and LHC.


title: Study of N*(1440) from J/Psi Decays

abstract:
  For $J/\Psi\to\bar pp \pi^0$ and $\bar pp\pi^+\pi^-$, the $\pi^0p$ and
$p\pi^+\pi^-$ systems are limited to be pure isospin 1/2 due to isospin
conservation. This is a big advantage in studying $N^*$ resonances from
$J/\Psi$ decays, compared with $\pi N$ and $\gamma N$ experiments. The process
$J/\Psi\to\bar pN^*$ or $p\bar N^*$ provides a new way to probe the internal
structure of the $N^*$ resonances. Here we report a quark model calculation for
$J/\Psi\to\bar pp$, $pN^*(1440)$ and $\bar N^*N^*$. The implication for the
internal structure of $N^*(1440)$ is discussed.


title:
On the direct evidence of time-reversal non-invariance in the $K^0-\bar
  K^0$ system

abstract:
  The measurements of the CP violation parameters by the CPLEAR experiment are
reviewed. It is shown that attempts to prove T-violation from the semileptonic
asymmetries are flawed by logical inconsistencies.


title:
New fermion mass textures from anomalous U(1) symmetries with baryon and
  lepton number conservation

abstract:
  In this paper, we present solutions to the fermion mass hierarchy problem in
the context of the minimal supersymmetric standard theory augmented by an
anomalous family-dependent U(1)_X symmetry. The latter is spontaneously broken
by non-zero vevs of a pair of singlet fields whose magnitude is determined
through the D- and F-flatness conditions of the superpotential. We derive the
general solutions to the anomaly cancellation conditions and show that they
allow numerous choices for the U(1)_X fermion charges which give several
fermion mass textures in agreement with the observed fermion mass hierarchy and
mixing. Solutions with U(1)_X fermion charge assignments are found which forbid
or substantially suppress the dangerous baryon and lepton number violating
operators and the lepton-higgs mixing coupling while a higgs mixing mass
(\mu-term) can be fixed at the electroweak level. We give a general
classification of the fermion mass textures with respect to the sum of the
doublet-higgs U(1)_X-charges and show that suppression of dimension-five
operators naturally occurs for various charge assignments. We work out cases
which retain a quartic term providing the left-handed neutrinos with Majorana
masses in the absence of right-handed neutrino components and consistent with
the experimental bounds. Although there exist solutions which naturally combine
all the above features with rather natural U(1)_X charges, the suppression of
the \mu-term occurs for particular assignments.


title: Neutrino masses and mixings in a seesaw framework

abstract:
  Assuming the seesaw mechanism for hierarchical neutrino masses, we calculate
the heavy neutrino masses under the hypotheses that the mixing in the Dirac
leptonic sector is similar to the quark mixing ($V_D \sim V_{CKM}$) and that
$M_{\nu} \sim M_u$ or $M_e$, where $M_{\nu}$ is the Dirac mass matrix of
neutrinos. As a result we find that for $M_{\nu} \sim M_u$ the vacuum
oscillation solution of the solar neutrino problem leads to a scale for the
heavy neutrino mass well above the unification scale, while for the MSW
solutions there is agreement with this scale. For $M_{\nu} \sim M_e$ the vacuum
solution is consistent with the unification scale, and the MSW solutions with
an intermediate scale. The mass of the lightest heavy neutrino can be as small
as $10^5$ GeV.


title: Neutrino mixing in Seesaw model

abstract:
  We study the neutrino mixing matrix (the MNS matrix) in the seesaw model. By
assuming a large mass hierarchy for the heavy right-handed Majorana mass, we
show that, in the diagonal Majorana base, the MNS matrix is determined by a
unitary matrix, $S$, which transforms the neutrino Yukawa matrix, $y_{\nu}$,
into a triangular form, $y_{\triangle}$. The mixing matrix of light leptons is
$V_{KM} S^{\prime *}$, where $V_{KM} \equiv {V_{Le}}^{\dagger} V_{L \nu}$
%$V_{Le}$ and $V_{L\nu}$ diagonalize %the Yukawa matrices of charged leptons,
%$y_e y_e^{\dagger}$, and neutrinos, $y_{\nu} y_{\nu}^{\dagger}$,
%respectively, and $S^{\prime *} \equiv {V_{L\nu}}^{\dagger} S^*$. Large mixing
may occur without fine tuning of the matrix elements of $y_{\triangle}$ even if
the usual KM-like matrix $V_{KM}$ is given by $V_{KM} =1$. This large mixing
naturally may satisfy the experimental lower bound of the mixing implied by the
atmospheric neutrino oscillation.


title: Event by Event Analysis and Entropy of Multiparticle Systems

abstract:
  The coincidence method of measuring the entropy of a system, proposed some
time ago by Ma, is generalized to include systems out of equilibrium. It is
suggested that the method can be adapted to analyze multiparticle states
produced in high-energy collisions.


title: Large-Nc QCD and Weak Matrix Elements

abstract:
  I report on recent progress in calculating electroweak processes within the
framework of QCD in the 1/Nc expansion.


title: Heavy Hybrids in QCD effective theories

abstract:
  We present model independent predictions on the short range behavior of the
energies of the gluonic excitations between static quarks (hybrid potentials)
in an effective field theory framework (pNRQCD).


title: Supersymmetry Unification Predictions for M_top V_cb and tan(beta)

abstract:
  We study the predictions for M_top, tan(beta) and V_cb in a popular texture
ansatze for the fermion mass matrices. We do this both for the Minimal
Supersymmetric Standard Model (MSSM) and for the simplest model (MSSM-BRpV)
where a bilinear R-Parity violating term is added to the superpotential. We
find that taking the experimental values for M_top and V_cb at 99 % C.L. and
the GUT relations h_b=h_tau and (V_cb)^2=h_c/h_t within 5 %, the large
tan(beta) solution, characteristic in the MSSM with bottom--tau unification,
becomes disallowed. In contrast the corresponding allowed region for the
MSSM-BRpV is slightly larger. We also find that important modifications occur
if we relax the texture conditions at the GUT scale. For example, if the GUT
relations are imposed at 40 %, the large tan(beta) branch in the MSSM becomes
fully allowed. In addition, in MSSM-BRpV the whole tan(beta)-M_top plane become
allowed, finding unification at any value of tan(beta).


title: Quarkonium: an effective field theory approach

abstract:
  We discuss heavy quarkonium in the framework of pNRQCD, a QCD effective
theory appropriate for the study of heavy quark bound systems.


title: Single W-boson Production at Linear Colliders

abstract:
  The process of single W-boson production at the energies of Next Linear
Colliders is considered. We discuss in details the contributions from s and t
channel diagrams, technical aspects of the complete tree level calculation with
a finite W width, and the quark mass effects.


title: SUSY Measurements at LHC

abstract:
  If SUSY exists at the TeV scale, finding it at the LHC should be quite easy.
The more difficult problem is to separate the various SUSY channels and to
measure masses and other parameters. Substantial progress on this has been made
within the ATLAS and CMS Collaborations.


title: SUSY Event Generators for Linear Colliders

abstract:
  The status of event generators for SUSY processes at future Linear Colliders
is briefly reviewed.


title: Small entries of neutrino mass matrices

abstract:
  We consider phenomenologically allowed structures of the neutrino mass matrix
in the case of three light neutrino species. Constraints from the solar,
atmospheric and reactor neutrino experiments as well as those from the
neutrinoless double beta decay are taken into account. Both hierarchical and
quasi-degenerate neutrino mass cases are studied. Assuming maximal
$\nu_\mu-\nu_\tau$ mixing we derive simple approximate expressions giving the
values of the neutrino masses and remaining lepton mixing angles in terms of
the entries of the neutrino mass matrix. Special attention is paid to the small
entries which are usually not specified in discussions of the neutrino mass
matrix textures. We specifically discuss the stability of neutrino masses and
lepton mixing angles with respect to the choice and variations of these small
entries.


title:
Drell-Yan and Diphoton production at Hadron Colliders and Low Scale
  Gravity Model

abstract:
  In the model of Arkani-Hamed, Dimopoulos, and Dvali where gravity is allowed
to propagate in the extra dimensions of very large size, virtual graviton
exchange between the standard model particles can give rise to signatures that
can be tested in collider experiments. We study these effects in dilepton and
diphoton production at hadron colliders. Specifically, we examine the double
differential cross-section in the invariant mass and scattering angle, which is
found to be useful in separating the gravity effects from the standard model.
In this work, sensitivity obtained using the double differential cross-section
is higher than that in previous studies based on single differential
distributions. Assuming no excess of events over the standard model
predictions, we obtain the following 95% confidence level lower limits on the
effective Planck scale: $0.9-1.5$ TeV in the Tevatron Run I, $1.3-2.5$ TeV in
Run IIa, $1.7-3.5$ TeV in Run IIb, and $6.5-12.8$ TeV at the LHC. The range of
numbers corresponds to the number of extra dimensions $n=7-2$.


title: See-saw Mechanism and Possible Generation Structure

abstract:
  On the basis of see-saw mechanism, possible generation structure is
investigated. Assuming that right-handed neutrinos are realistic particles
below GUTs mass, it is shown that there is a choice of new scheme of
generation,where the combination of leptons and quarks is different from the
ordinary one. Our scheme predict a new proton decay mode.


title:
Helicity amplitudes for the small--angle process e^-e^{\pm}\to
  e^-\gamma\gamma + e^{\pm} with both photons along one direction and its cross
  channel

abstract:
  We study the small--angle double bremsstrahlung in $e^-e^\pm$ scattering for
a jet kinematics where both photons move along the electron direction. This
region gives the main contribution to the cross section. We present analytic
expressions for all 64 amplitudes with arbitrary helicity states of the initial
and final leptons and the produced photons convenient for analytic and
numerical studies. The accuracy of the obtained amplitudes is given omitting
only terms of the order of m^2/E_j^2, \theta_j^2 and \theta_j m/E_j. The
helicity amplitudes for the cross channel \gamma e^\pm \to \gamma e^+e^- +
e^\pm are given. Several limits for the helicity amplitudes of hard or soft
final particles are considered.


title: Inelastic $J/\psi$ production in polarized photon-hadron collisions

abstract:
  Presented here is a calculation of inelastic $J/\psi$ production in polarized
photon-hadron collisions under the framework of NRQCD factorization formalism.
We consider the photoproduction of $\jpsi$ in the energy range relevant to
HERA. The Weizs\"acker-Williams approximation is adopted in the evaluation of
the cross sections for $ep$ collisions. We found that this process can give
another independent test for the color-octet mechanism, and the different
features for the two color-octet processes may provide further informations on
the mechanism for inelastic $\jpsi$ photoproduction. And the discrepancy on the
production asymmetry $A$ between various sets of polarized gluon distribution
functions is also found to be distinctive.


title:
Multilepton production via top flavour-changing neutral couplings at the
  CERN LHC

abstract:
  Zt and gamma t production with Z -> l+ l- and t -> Wb -> l nu b provides the
best determination of top flavour-changing neutral couplings at the LHC. The
bounds on tc couplings eventually derived from these processes are similar to
those expected from top decays, while the limits on tu couplings are better by
a factor of two. The other significant Z and W decay modes are also
investigated.


title: Future ep Physics: The Outlook for HERA

abstract:
  The luminosity of the electron-proton collider, HERA, will be increased by a
factor of five during the long shutdown in the year 2000. At the same time
longitudinal lepton beam polarisation will be provided for the collider
experiments H1 and ZEUS. These far reaching upgrades to the machine will be
matched by upgrades to the detectors. The result will be a unique facility for
the study of the structure of the proton and the nature of the strong and
electroweak interactions. The physics potential of the upgraded accelerator is
discussed here together with a brief description of the HERA machine and
collider detector upgrades.


title: Estimating eps'/eps . A user's manual

abstract:
  I review the current theoretical estimates of the CP-violating parameter
eps'/eps, compare them to the experimental result and suggest a few guidelines
in using the theoretical results.


title: Asymptotic structure of perturbative series for tau lepton observables

abstract:
  We analyze tau lepton decay observables, namely moments of the hadronic
spectral density in the finite energy interval (0,M_\tau), within finite order
perturbation theory including \alpha_s^4 corrections. The start of asymptotic
growth of perturbation theory series is found at this order in a scheme
invariant manner. We establish the ultimate accuracy of finite order
perturbation theory predictions and discuss the construction of optimal
observables.


title: Power corrections and renormalon resummation for the average thrust

abstract:
  Infrared power corrections for the average thrust < T > in e+e- annihilation
are analyzed in the framework of renormalon resummation, motivated by analogy
with the skeleton expansion in QED and the BLM approach. Performing the
``massive gluon'' renormalon integral a renormalization scheme invariant result
is obtained. We find that a major part of the discrepancy between the known
next-to-leading order (NLO) calculation and experiment can be explained by
resummation of higher order perturbative terms. This fact does not preclude the
infrared finite coupling interpretation with a substantial 1/Q power term.
Fitting the regularized perturbative sum plus a 1/Q term to experimental data
yields alpha_s^{MSbar}(M_Z)=0.110 \pm 0.006.


title: Generic Gravitational Corrections to Gauge Couplings in SUSY SU(5) GUTs

abstract:
  We study non-universal corrections to the gauge couplings due to higher
dimensional operators in supersymmetric SU(5) grand unified theories. The
corrections are, in general, parametrized by three components originating from
{\bf 24}, {\bf 75} and {\bf 200} representations. We consider the prediction of
$\alpha_3(M_Z)$ along each {\bf 24}, {\bf 75} and {\bf 200} direction, and
their linear combinations. The magnitude of GUT scale and its effects on proton
decay are discussed. Non-SUSY case is also examined.


title:
Implications for relic neutralinos of the theoretical uncertainties in
  the neutralino-nucleon cross-section

abstract:
  We discuss the effect induced on the neutralino-nucleon 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. We also comment on implications of the mentioned
uncertainties for experiments of indirect dark matter detection.


title:
Chiral Symmetry Restoration and Dileptons in Relativistic Heavy-Ion
  Collisions

abstract:
  The current theoretical status in the analysis and interpretation of low-mass
dilepton measurements in (ultra-) relativistic heavy-ion experiments is
reviewed. Special emphasis is put on potential signals of (partial) restoration
of dynamically broken chiral symmetry in a hot and dense hadronic medium. It
follows from chiral symmetry alone that parity partners of hadronic correlation
functions must become identical when the symmetry is restored. The assessment
of medium effects in the vector channel, which governs the dilepton production,
thus necessitates a simultaneous treatment of the vector and axialvector
degrees of freedom. While significant progress in this respect has been made
some open questions remain in establishing a rigorous link in the mass region
below 1 GeV. From the present calculations a suggestive 'quark-hadron duality'
emerges near the phase boundary. It implies substantial medium effects in the
dilepton signal from the hadronic phase which smoothly matches a perturbative
description within the plasma phase.


title: Deep Inelastic e-gamma Scattering at High Q2

abstract:
  The electromagnetic and weak structure functions of the photon can be studied
in the deep inelastic electron-photon processes e+gamma -> e+X and e+gamma ->
nu+X. While at low energies only virtual photon exchange is operative in the
neutral-current process, additional Z-exchange becomes relevant for high Q2 of
order MZ^2 at e+e- linear colliders. Likewise the charged-current process can
be observed at these high energy colliders. By measuring the electroweak
neutral- and charged-current structure functions, the up- and down-type quark
content of the photon can be determined separately.


title: Neutrinos From the Next Galactic Supernova

abstract:
  The next core-collapse supernova in our Galaxy will be a spectacular event,
with some $10^4$ neutrino detections in total expected among several detectors.
This data will allow unprecedented tests of neutrino properties and new
opportunities in astrophysics. In this paper, I focus on two main topics: (1)
Measurement of the $\nu_\mu$ and $\nu_\tau$ masses by time-of-flight, with an
emphasis on introducing as little supernova model dependence as possible, and
(2) Methods for locating a supernova by its neutrinos in advance of the light,
which may allow improved astronomical observations. In the latter, I also
discuss the recent result that the positrons from $\bar{\nu}_e + p \to e^+ + n$
are not isotropically emitted, as commonly thought.


title:
Testing the Nature of Kaluza-Klein Excitations at Future Lepton
  Colliders

abstract:
  With one extra dimension, current high precision electroweak data constrain
the masses of the first Kaluza-Klein excitations of the Standard Model gauge
fields to lie above $\simeq 4$ TeV. States with masses not much larger than
this should be observable at the LHC. However, even for first excitation masses
close to this lower bound, the second set of excitations will be too heavy to
be produced thus eliminating the possibility of realizing the cleanest
signature for KK scenarios. Previous studies of heavy $Z'$ and $W'$ production
in this mass range at the LHC have demonstrated that very little information
can be obtained about their couplings to the conventional fermions given the
limited available statistics and imply that the LHC cannot distinguish an
ordinary $Z'$ from the degenerate pair of the first KK excitations of the
$\gamma$ and $Z$. In this paper we discuss the capability of lepton colliders
with center of mass energies significantly below the excitation mass to resolve
this ambiguity. In addition, we examine how direct measurements obtained on and
near the top of the first excitation peak at lepton colliders can confirm these
results. For more than one extra dimension we demonstrate that it is likely
that the first KK excitation is too massive to be produced at the LHC.


title: Physics Beyond the Standard Model

abstract:
  These lectures describe why one believes there is physics beyond the Standard
Model and review the expectations of three alternative explanations for the
Fermi scale. After examining constraints and hints for beyond the Standard
Model physics coming from experiment, I discuss, in turn, dynamical symmetry
breaking, supersymmetry and extra compact dimension scenarios associated with
the electroweak breakdown.


title: QCD Technology: Light-Cone Quantization and Commensurate Scale Relations

abstract:
  I discuss several theoretical tools which are useful for analyzing
perturbative and non-perturbative problems in quantum chromodynamics, including
(a) the light-cone Fock expansion, (b) the effective charge $\alpha_V$, (c)
conformal symmetry, and (d) commensurate scale relations. Light-cone Fock-state
wavefunctions encode the properties of a hadron in terms of its fundamental
quark and gluon degrees of freedom. Given the proton's light-cone
wavefunctions, one can compute not only the quark and gluon distributions
measured in deep inelastic lepton-proton scattering, but also the multi-parton
correlations which control the distribution of particles in the proton
fragmentation region and dynamical higher twist effects. Light-cone
wavefunctions also provide a systematic framework for evaluating exclusive
hadronic matrix elements, including timelike heavy hadron decay amplitudes and
form factors. The $\alpha_V$ coupling, defined from the QCD heavy quark
potential, provides a physical expansion parameter for perturbative QCD with an
analytic dependence on the fermion masses which is now known to two-loop order.
Conformal symmetry provides a template for QCD predictions, including relations
between observables which are present even in a theory which is not scale
invariant. Commensurate scale relations are perturbative QCD predictions based
on conformal symmetry relating observable to observable at fixed relative
scale. Such relations have no renormalization scale or scheme ambiguity.


title: Hadronic Probes of the Polarized Intrinsic Strangeness of the Nucleon

abstract:
  We have previously interpreted the various large apparent violations of the
naive Okubo-Zweig-Iizuka (OZI) rule found in many channels in $\bar{p}p$
annihilation at LEAR as evidence for an intrinsic polarized $\bar{s}s$
component of the nucleon wave function. The model is further supported by new
data from LEAR and elsewhere. Here we discuss in more detail the possible form
of the $\bar{s}s$ component of the nucleon wave function, interpret the new
data and clarify the relative roles of strangeness shake-out and rearrangement,
discuss whether alternative interpretations are still allowed by the new data,
and propose more tests of the model.


title: Overview of Kaon Physics

abstract:
  In this overview, I discuss some of the open issues in Kaon physics. After
briefly touching on lattice calculations of Kaon dynamics and tests of CPT, my
main focus of attention is on epsilon prime over epsilon and on constraints on
the CKM model. The impact of rare K- decays and of experiments with B-mesons
for addressing the issue of CP-violation is also discussed. The importance of
looking for signals of flavor-conserving CP violating phases is emphasized.


title:
Interference in Exclusive Vector Meson Production in Heavy Ion
  Collisions

abstract:
  Photons emitted from the electromagnetic fields of relativistic heavy ions
can fluctuate into quark anti-quark pairs and scatter from a target nucleus,
emerging as vector mesons. These coherent interactions are identifiable by
final states consisting of the two nuclei and a vector meson with a small
transverse momentum. The emitters and targets can switch roles, and the two
possibilities are indistinguishable, so interference may occur. Vector mesons
are negative parity so the amplitudes have opposite signs. When the meson
transverse wavelength is larger than the impact parameter, the interference is
large and destructive.
  The short-lived vector mesons decay before amplitudes from the two sources
can overlap, and so cannot interfere directly. However, the decay products are
emitted in an entangled state, and the interference depends on observing the
complete final state. The non-local wave function is an example of the
Einstein-Podolsky-Rosen paradox.


title: R-Parity Violation: Origin of $\mu $-Term and Other Consequences

abstract:
  We propose a new mechanism in which the generation of the supersymmetric $\mu
$-term as well charged lepton masses is closely tied to R-parity violation
involving heavy vector-like families . A realistic example based on
$SU(3)_c\times SU(2)_L\times U(1)_Y$, supplemented by the symmetry ${\cal
R}\times {\cal U}(1)$, is presented, where ${\cal R}$ (${\cal U}(1)$) denotes a
continuous $R$ (flavor) symmetry. In addition to the $\mu $-term, the charged
fermion mass hierarchies and mixings, as well as baryon number conservation are
also nicely explained. Bilinear R-parity violating coupling involving the first
generation gives rise to neutrino mass relevant for the small angle
$\nu_e-\nu_s$ MSW oscillations, where $\nu_s $ denotes a sterile state. The
atmospheric neutrino puzzle is resolved via maximal mixing angle $\nu_{\mu
}-\nu_{\tau}$ oscillations. The decay of the lightest neutralino (LSP) and
leptogenesis are briefly discussed.


title: Hadronic electromagnetic form factors and color transparency

abstract:
  We review the current status of electromagnetic form factor calculations in
perturbative QCD. There is growing evidence that factorization prescriptions
involving a transverse coordinate integration, such as that of Li and Sterman,
are more appropriate than the prescription of LePage and Brodsky. Color
transparency is naturally described within the formalism. We report the first
explicit calculations of color transparency and nuclear filtering as
perturbatively calculable phenomena.


title: Axion in large extra dimension

abstract:
  We examine the axion model in the large extra dimensions scenario with TeV
scale gravity. To obtain an intermediate-scale decay constant of the axion, the
axion is assumed to live in a sub-spacetime (brane) of the whole bulk. In this
model there appear Kaluza-Klein modes of the axion which have stronger
interaction than those of the graviton. The axion brane plays a role of
absorber of the graviton Kaluza-Klein modes. We discuss various cosmological
constraints as well as astrophysical ones and show that the model is viable for
certain choices of the dimensionality of the axion brane. The structure of the
model proposed here provides a viable realization of the fat brane idea to
relax otherwise very severe cosmological constraints.


title: Lightest glueball and scalar meson nonet in production and decay

abstract:
  Recent results concerning the evidence and classification of the
J^{PC}=0^{++} states, obtained with P. Minkowski, are presented: The isoscalars
f_0(980) and f_0(1500) are classified as members of the 0^{++} nonet, while the
broad state called f_0(400-1200) and the state f_0(1370) are considered as
different components of a single broad resonance, the lowest-lying 0^{++}
glueball. Furthermore, we propose the investigation of glueball production in
the fragmentation region of gluon jets.


title: Confronting electroweak precision measurements with New Physics models

abstract:
  Precision experiments, such as those performed at LEP and SLC, offer us an
excellent opportunity to constrain extended gauge model parameters. To this
end, it is often assumed, that in order to obtain more reliable estimates, one
should include the sizable one--loop Standard Model (SM) corrections, which
modify the $Z^0$ couplings as well as other observables. This conviction is
based on the belief that the higher order contributions from the ``extension
sector'' will be numerically small. However, the structure of higher order
corrections can be quite different when comparing the SM with its extension,
thus one should avoid assumptions which do not care about such facts. This is
the case for all models with $\rho_{\rm tree} \equiv
M_W^2/(M_{Z}^2\cos^2{\Theta_W}) \neq 1$. As an example, both the manifest
left-right symmetric model and the $SU(2)_L \otimes U(1)_Y \otimes
\tilde{U}(1)$ model, with an additional $Z'$ boson, are discussed and special
attention to the top contribution to $\Delta \rho$ is given. We conclude that
the only sensible way to confront a model with the experimental data is to
renormalize it self-consistently, if not, parameters which depend strongly on
quantum effects should be left free in fits, though essential physics is lost
in this way. We should note that arguments given here allow us to state that at
the level of loop corrections (indirect effects) there is nothing like a
``model independent global analysis'' of the data.


title:
The gamma gamma to Z Z process and the search for virtual SUSY effects
  at a gamma gamma Collider

abstract:
  We study the helicity amplitudes of the process gamma gamma to ZZ in the
Standard Model at high energy. These amplitudes receive contributions from the
W and charged quark and lepton loops, analogous to those encountered in the
gamma gamma to gamma gamma, gamma Z cases studied before. But gamma gamma to ZZ
also receives contributions from the Higgs s-channel poles involving the
effective Higgs-gamma gamma vertex. At energies of about 300 GeV, the
amplitudes in all three processes are mainly helicity-conserving and almost
purely imaginary; which renders them a very useful tool in searching for New
Physics. As an example, a SUSY case is studied, and the signatures due to the
virtual effects induced by a chargino-, charged slepton- or a lightest
stop-loop in gamma gamma to ZZ, are explored. These signatures, combined with
the analogous ones in gamma gamma to gamma gamma and gamma gamma to gamma Z,
should help identifying the nature of possible New Physics particles.


title: Strange Quark Mass Determination from Cabibbo-Suppressed Tau Decays

abstract:
  We present a general analysis of SU(3) breaking effects in the semi-inclusive
tau hadronic width. The recent ALEPH measurements of the inclusive
Cabibbo--suppressed decay width of the tau and several moments of its invariant
mass distribution are used to determine the value of the strange quark mass. We
obtain, in the MS scheme, m_s(M_\tau^2) = (119\pm 24) MeV to O(\alpha_s^3),
which corresponds to m_s (1 GeV^2) = (164 \pm 33) MeV, m_s(4 GeV^2) = (114\pm
23) MeV .


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

abstract:
  We report on recent advances at understanding the $\Delta I= 1/2$ rule for
kaons. We get reasonable matching between short-- and long--distances for
scales between between 0.6 and 1.0 GeV and reproduce the $\Delta I=1/2$ rule
huge enhancement in the chiral limit. A detailed analysis of the different
contributions to the relevant octet and 27-plet couplings is done. For the
$B_6^{(1/2)}(\mu) \equiv < (\pi\pi)_0 | Q_6 | K > / [< (\pi\pi)_0 | Q_6 | K >
{\Large|}_{N_c}]$ parameter, we get in the chiral limit $B_6^{(1/2)}(\mu) = 2.2
\pm 0.5$ for scales $\mu \in [0.6, 1.0]$ GeV.


title:
On the Convergence of the Expansion of Renormalization Group Flow
  Equation

abstract:
  We compare and discuss the dependence of a polynomial truncation of the
effective potential used to solve exact renormalization group flow equation for
a model with fermionic interaction (linear sigma model) with a grid solution.
The sensitivity of the results on the underlying cutoff function is discussed.
We explore the validity of the expansion method for second and first-order
phase transitions.


title: Cosmology II: From the Planck Time to BBN

abstract:
  Progress in early Universe cosmology, including strings, extra dimensions,
inflation, phase transitions, and baryogenesis, is reviewed.


title:
Massive Higher-dimensional Gauge Fields as Messengers of Supersymmetry
  Breaking

abstract:
  We consider theories with one or more compact dimensions with size r > 1/M,
where M is the fundamental Planck scale, with the visible and hidden sectors
localized on spatially separated "3-branes." We show that a bulk U(1) gauge
field spontaneously broken on the hidden-sector 3-brane is an attractive
candidate for the messenger of supersymmetry breaking. In this scenario scalar
mass-squared terms are proportional to U(1) charges, and therefore naturally
conserve flavor. Arbitrary flavor violation at the Planck scale gives rise to
exponentially suppressed flavor violation at low energies. Gaugino masses can
be generated if the standard gauge fields propagate in the bulk; \mu and B\mu
terms can be generated by the Giudice-Masiero or by the VEV of a singlet in the
visible sector. The latter case naturally solves the SUSY CP problem. Realistic
phenomenology can be obtained either if all microscopic parameters are order
one in units of M, or if the theory is strongly coupled at the scale M. (For
the latter case, we estimate parameters by extending "naive dimensional
analysis" to higher-dimension theories with branes.) In either case, the only
unexplained hierarchy is the "large" size of the extra dimensions in
fundamental units, which need only be an order of magnitude. All soft masses
are naturally within an order of magnitude of m_{3/2}, and trilinear scalar
couplings are negligible. Squark and slepton masses can naturally unify even in
the absence of grand unification.


title: Permutation Symmetry for Neutrino and Charged-Lepton Mass Matrices

abstract:
  The permutation symmetry $S_3$ is appplied to obtain two equal Majorana
neutrino masses, while maintaining three different charged-lepton masses and
suppressing neutrinoless double beta decay. The resulting radiative splitting
of the two neutrinos is shown to be suitable for solar neutrino vacuum
oscillations.


title:
The Solar Neutrino Problem and Gravitationally Induced Long-wavelength
  Neutrino Oscillation

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


title: New constraint on the minimal SUSY GUT model from proton decay

abstract:
  We present results of reanalysis on proton decay in the minimal SU(5) SUSY
GUT model. Unlike previous analyses, we take into account a Higgsino dressing
diagram of dimension 5 operator with right-handed matter fields ($RRRR$
operator). It is shown that this diagram gives a significant contribution for
$p \to K^{+}\bar{\nu}_{\tau}$. Constraints on the colored Higgs mass $M_C$ and
the sfermion mass $m_{\tilde{f}}$ from Super-Kamiokande limit become
considerably stronger than those in the previous analyses: $M_C > 6.5\times
10^{16} \gev$ for $m_{\tilde{f}} < 1 \tev$. The minimal model with
$m_{\tilde{f}} \lsim 2 \tev$ is excluded if we require the validity of this
model up to the Planck scale.


title: Test of Physics beyond the Standard Model in Nuclei

abstract:
  The modern theories of Grand Unification (GUT) and supersymmetric (SUSY)
extensions of standard model (SM) suppose that the conservation laws of the SM
may be violated to some small degree. The nuclei are well-suited as a
laboratory to test fundamental symmetries and fundamental interactions like
lepton flavor (LF) and lepton number (LN) conservation. A prominent role
between experiments looking for LF and total LN violation play yet not observed
processes of neutrinoless double beta decay. The GUT's and SUSY models offer a
variety of mechanisms which allow this process to occur. They are based on
mixing of Majorana neutrinos and/or R-parity violation hypothesis. Although the
neutrinoless double beta decay has not been seen it is possible to extract from
the lower limits of the lifetime upper limits for the effective electron
Majorana neutrino mass, effective right handed weak interaction parameters, the
effective Majoron coupling constant, R-parity violating SUSY parameters etc.
  In this work the limits on the LN violating parameters extracted from current
neutrinoless double beta decay experiments are listed. Studies in respect to
future neutrinoless double beta decay experimental projects are also presented.


title: The Polarized Structure Function g_2: A Lattice Study Revisited

abstract:
  A recent lattice calculation of the spin-dependent structure function g_2 is
revisited. It has been recognized that the twist-three operator, which gives
rise to d_2, mixes non-perturbatively with operators of lower dimensions under
renormalization. This changes the results substantially.


title: Neutrino mixing and CP-violation

abstract:
  The prospects of measuring the leptonic angles and CP-odd phases at a
neutrino factory are discussed in two scenarios: 1) three active neutrinos as
indicated by the present ensemble of atmospheric plus solar data; 2) three
active plus one sterile neutrino when the LSND signal is also taken into
account. For the latter we develop one and two mass dominance approximations.
The appearance of wrong sign muons in long baseline experiments and tau leptons
in short baseline ones provides the best tests of CP-violation in scenarios 1)
and 2), respectively.


title: Warped Phenomenology

abstract:
  We explore the phenomenology associated with the recently proposed localized
gravity model of Randall and Sundrum where gravity propagates in a
5-dimensional non-factorizable geometry and generates the 4-dimensional
weak-Planck scale hierarchy by an exponential function of the compactification
radius, called a warp factor. The Kaluza-Klein tower of gravitons which emerge
in this scenario have strikingly different properties than in the factorizable
case with large extra dimensions. We derive the form of the graviton tower
interactions with the Standard Model fields and examine their direct production
in Drell-Yan and dijet events at the Tevatron and LHC as well as the KK
spectrum line-shape at high-energy linear \epem colliders. In the case where
the first KK excitation is observed, we outline the procedure to uniquely
determine the parameters of this scenario. We also investigate the effect of KK
tower exchanges in contact interaction searches. We find that present
experiments can place meaningful constraints on the parameters of this model.


title: Parametric Resonance For Complex Fields

abstract:
  Recently, there have been studies of parametric resonance decay of
oscillating real homogeneous cosmological scalar fields, in both the
narrow-band and broad-band case, primarily within the context of inflaton decay
and (p)reheating. However, many realistic models of particle cosmology, such as
supersymmetric ones, inherently involve complex scalar fields. In the
oscillations of complex scalars, a relative phase between the oscillations in
the real and imaginary components may prevent the violations of adiabaticity
that have been argued to underly broad-band parametric resonance. In this
paper, we give a treatment of parametric resonance for the decay of homogeneous
complex scalar fields, analyzing properties of the resonance in the presence of
out of phase oscillations of the real and imaginary components. For
phase-invariant coupling of the driving parameter field to the decay field, and
Mathieu type resonance, we give an explicit mapping from the complex resonance
case to an equivalent real case with shifted resonance parameters. In addition,
we consider the consequences of the complex field case as they apply to
``instant preheating,'' the explosive decay of non-convex potentials, and
resonance in an expanding FRW universe. Applications of our considerations to
supersymmetric cosmological models will be presented elsewhere.


title: Charges from Dressed Matter: Construction

abstract:
  There is a widespread belief in particle physics that there is no
relativistic description of a charged particle. This is claimed to be due to
persistent, long range interactions which distort the in and out going plane
waves and generate infra-red divergences. In this paper we will show that this
is not the case in QED. We construct locally gauge invariant charged fields
which do create in and out Fock states. In a companion paper we demonstrate
that the Green's functions of these fields have a good pole structure
describing particle propagation.


title:
Longitudinal Polarization in $K_L \to \mu^+ \mu^-$ in MSSM with large
  $tan\beta$

abstract:
  A complete experiment on decay $K_L \to l^+ l^-$ will not only consist of
measurement of the decay rates but also lepton polarization etc. These
additional observations will yield tests of CP invariance in these decays. In
$K_L$ and $K_S$ decays, the e mode is slower than the $\mu$ mode by roughly
$(m_e/m_\mu)^2$ \cite{sehgal1}. As well discussed in literature \cite{herczeg}
the Standard Model contribution to the lepton polarization is of order $2
\times \sim 10^{-3}$. We show that in MSSM with large \tanbeta and light higgs
masses ($\sim 2 M_W$), the longitudinal lepton polarization in $K_L \to \mu^+
\mu^-$ can be enhanced to a higher value, of about $10^{-2}$.


title:
Non-equilibrium quantum plasmas in scalar QED: photon production,
  magnetic and Debye masses, and conductivity

abstract:
  We study the generation of a non-equilibrium plasma in scalar QED with N
charged scalar fields through spinodal instabilities in the case of a super
cooled second order phase transition and parametric amplification when the
order parameter oscillates with large amplitude around the minimum of the
potential.The focus is to study the non-equilibrium electromagnetic properties
of the plasma, such as photon production, electric and magnetic screening and
conductivity. A novel kinetic equation is introduced to compute photon
production far away from equilibrium in the large N limit and lowest order in
the electromagnetic coupling.During the early stages of the dynamics the photon
density grows exponentially and asymptotically the amplitude and frequency
distribution becomes \sim alpha m^2/[lambda^2 \omega^3] with lambda the scalar
self-coupling and m the scalar mass.In the case of a phase transition,electric
and magnetic fields are correlated on distances xi(t) \sim sqrt{t} during the
early stages and the power spectrum is peaked at low momentum. Magnetic and
Debye screening masses are defined out of equilibrium. The magnetic mass
vanishes out of equilibrium in this abelian models. The Debye mass turns to be
m^2_{Deb} \sim alpha m^2/lambda for a supercooled phase transition while in the
case of an oscillating order parameter an interpolating time dependent Debye
mass grows as alpha sqrt{m t}/lambda due to a non-linear resonance at low
momentum in the charged particle distribution. The build-up of the transverse
electric conductivity is studied during the formation of the non-equilibrium
plasma. Its long wavelength limit reaches a value sigma_{k\approx 0} \sim alpha
m/lambda at the end of the stage of linear instabilities. Its asymptotic form
in terms of the non-equilibrium particle distribution functions is derived.


title: Masses and Couplings of the Lightest Higgs Bosons in the (M+1)SSM

abstract:
  We study the upper limits on the mass of the lightest and second lightest CP
even Higgs bosons in the (M+1)SSM, the MSSM extended by a gauge singlet. The
dominant two loop contributions to the effective potential are included, which
reduce the Higgs masses by 10 GeV. Since the coupling R of the lightest Higgs
scalar to gauge bosons can be small, we study in detail the relations between
the masses and couplings of both lightest scalars. We present upper bounds on
the mass of a 'strongly' coupled Higgs (R > 1/2) as a function of lower
experimental limits on the mass of a 'weakly' coupled Higgs (R < 1/2). With the
help of these results, the whole parameter space of the model can be covered by
Higgs boson searches.