title: Testing the left-right symmetric model at linear collider

abstract:
  We review possible tests of the left-right electroweak model at future linear
colliders, concentrating on signatures of the central predictions of the model,
i.e. right-handed currents, massive neutrinos and triplet Higgs bosons. We
analyse processes in e+e-, e-e- and e-\gamma collision modes. We present the
mass reaches for the new particles at linear collider and sensitivities to
their couplings.


title: The chiral phase transition, random matrix models, and lattice data

abstract:
  We present two pieces of evidence in support of the conjecture that the
microscopic spectral density of the Dirac operator is a universal quantity.
First, we compare lattice data to predictions from random matrix theory.
Second, we show that the functional form of the microscopic spectral
correlations remains unchanged in random matrix models which take account of
finite temperature. Furthermore, we present a random matrix model for the
chiral phase transition in which all Matsubara frequencies are included.


title: The Light-Front Model for Exclusive Semileptonic B- and D-decays

abstract:
  An explicit relativistic light-front quark model is presented which gives the
momentum transfer dependent form factors of weak hadronic currents among heavy
pseudoscalar and vector mesons in the whole accessible kinematic region $ 0\leq
q^2 \leq q^2_{max} $. For the numerical investigations of the $ B \to D^* l
\nu_l $, $ B \to \rho l \nu_l $, $ D\to K^* l \nu_l $ and $ D \to \rho l \nu_l
$ semileptonic decays the equal time wave functions corresponding to the
updated version of the ISGW model are adopted. Using the available experimental
information on branching fractions $ BR(B \to D^* l \nu_l) $ and $ BR(B \to
\rho l \nu_l) $ the CKM parameters $ V_{cb} $ and $ V_{ub} $ were estimated: $
|V_{cb}| = 0.036 \pm 0.004 $, $ |V_{ub}| = 0.0033 \pm 0.0004 $. The model is
further tested by comparison with experimental data, QCD sum rules and lattice
calculations.


title: The Inverse Amplitude Method and Chiral Perturbation Theory to two Loops

abstract:
  The inverse amplitude method is analysed to two-loop order in the chiral
expansion in the case of $\pi\pi$ scattering and the pion form factors. The
analysis is mainly restricted to the elastic approximation but the possible
extension to the inelastic case is also discussed in some detail. It is shown
how the two-loop approach improves the inverse amplitude method applied to
one-loop order in the chiral expansion. For both $\pi\pi$ scattering and the
pion form factors, it is in fact found that the inverse amplitude method to
two-loop order agrees remarkable well with the experimental data up to energies
where inelasticities become essential. At somewhat lower energies, the two-loop
approach compares well with the one-loop approximation, and in the threshold
region they both agree with chiral perturbation theory. This suggests that the
inverse amplitude method is indeed a rather systematic way of improving chiral
perturbation theory order by order in the chiral expansion.


title: The four-loop beta-function in Quantum Chromodynamics

abstract:
  We present the analytical calculation of the four-loop QCD beta-function
within the minimal subtraction scheme.


title: The Future of Mr. Jefferson's Laboratory (nee CEBAF)

abstract:
  We present one viewpoint plus some general information on the plans for
energy upgrades and physics research at the Jefferson Laboratory.


title:
The tan(beta) - M_H^\pm bound from inclusive semi-tauonic B-decays in
  the MSSM

abstract:
  We compute the O(alpha_s) SUSY-QCD corrections to the W and charged Higgs
mediated inclusive semi-tauonic B-decay, B->tau antineutrino_tau X. Combining
the SUSY contribution with the SM result obtained from the heavy quark
effective field theory, plus ordinary QCD corrections, we find that the allowed
region in the (tan(beta),M_H^\pm)-plane could be significantly modified by the
short-distance supersymmetric effects. Since the sensitivity to the SUSY
parameters other than mu (the higgsino mixing mass) is rather low, the
following effective bound emerges for mu<0 at the 2 sigma level: tan(beta)~<
0.43 (M_H^\pm/GeV). Remarkably, for mu>0 there could be no bound at all.
Finally, we provide a combined (tan(beta,M_H^\pm) exclusion plot using our
B-meson results together with the recent data from top quark decays.


title: Hot B violation, the lattice, and hard thermal loops

abstract:
  It has recently been argued that the rate per unit volume of baryon number
violation (topological transitions) in the hot, symmetric phase of electroweak
theory is of the form $\eta \alpha_w^5 T^4$ in the weak-coupling limit, where
$\eta$ is a non-perturbative numerical coefficient. Over the past several
years, there have been attempts to extract the rate of baryon number violation
from real-time simulations of classical thermal field theory on a spatial
lattice. Unfortunately, the coefficient $\eta$ will not be the same for
classical lattice theories and the real quantum theory. However, by analyzing
the appropriate effective theory on the lattice using the method of hard
thermal loops, I show that the only obstruction to precisely relating the rates
in the real and lattice theories is the fact that the long-distance physics on
the lattice is not rotationally invariant. (This is unlike Euclidean-time
measurements, where rotational invariance is always recovered in the continuum
limit.) I then propose how this violation of rotational invariance can be
eliminated - and the real B violation rate measured - by choosing an
appropriate lattice Hamiltonian. I also propose a rough measure of the
systematic error to be expected from using simpler, unimproved Hamiltonians. As
a byproduct of my investigation, the plasma frequency and Debye mass are
computed for classical thermal field theory on the lattice.


title:
A Solution to the $\mu$ Problem in Gauge-mediated Supersymmetry-breaking
  Models

abstract:
  We point out that a sector required to set the cosmological constant to zero
in gauge-mediated supersymmetry-breaking models naturally produces a
supersymmetry-invariant mass ($\mu$ term) for Higgs doublets of the order of
the electroweak scale. Since this new sector preserves the supersymmetry, it
does not generate supersymmetry-breaking masses for the Higgs doublets and thus
the $\mu$ problem is solved.


title: Hadronic Final State in Deep-inelastic Scattering at HERA

abstract:
  Data on the hadronic final state of deep-inelastic events at the ep collider
HERA are reviewed. Fragmentation properties in the current region extracted
from charged particle spectra are compared to e+e- and fixed target experiments
at lower center of mass energies. A measurement of the strong coupling constant
from integrated jet rates is presented and prospects to extract the gluon
density in the proton by tagging vector mesons are discussed. Data on the
inclusive mean transverse energy together with the transverse momentum
distribution of single charged particles indicate an increased gluon activity
in the central rapidity region when the phase space is enlarged. The
measurement of the forward jet cross-section is discussed. Keeping the phase
space fixed, the mean transverse energy and the mean charged multiplicity for
certain rapidity ranges is found to behave analogously to ppbar collisions.


title: Annihilation, Rescattering, and CP Asymmetries in B Meson Decays

abstract:
  A number of $B$ meson decays may proceed only through participation of the
spectator quark, whether through amplitudes proportional to $f_B/m_B$ or via
rescattering from other less-suppressed amplitudes. An expected hierarchy of
amplitudes in the absence of rescattering will be violated by rescattering
corrections. Such violations could point the way toward channels in which
final-state interactions could be important. Cases in which final state phases
can lead to large CP asymmetries are pointed out.


title: Dispersive derivation of the trace anomaly

abstract:
  We present a simple derivation of the one-loop trace anomaly in spinor QED
through dispersion relations, avoiding completely any ultraviolet
regularization. The anomaly can be expressed as a convergent sum rule for the
imaginary part of a relevant formfactor. In the massless limit, the imaginary
part produces a delta-function singularity at zero external momentum squared.
Such a treatment reveals an "infrared face" of the trace anomaly, in striking
similarity with the well-known case of the axial anomaly.


title:
QCD corrections to Higgs boson decays into squarks in the Minimal
  Supersymmetric Standard Model

abstract:
  We calculate the supersymmetric QCD corrections in order $\alpha_s$ to the
the widths of the Higgs boson decays $H^+ \to \st \bar\sb$ and $H^0, A^0 \to
\st \bar\st, \sb \bar\sb$ in the on--shell scheme within the Minimal
Supersymmetric Standard Model. We find that the QCD corrections are
significant, but that the squark pair decay modes are still dominant in a wide
parameter region.


title:
Flavour Changing Neutral Current Decays of Heavy Baryons: The Case
  $\Lambda_b \to \Lambda \gamma$

abstract:
  We investigate the rare decay $\Lambda_b \to \Lambda \gamma$ which receives
both short and long distance contributions. We estimate the long distance
contributions and find them very small. The form factors are obtained from
$\Lambda_c \to \Lambda \ell \bar{\nu}_\ell$ using heavy quark symmetry and a
pole model. The short distance piece opens a window to new physics and we
discuss the sensitivity of $\Lambda_b \to \Lambda \gamma$ to such effects.


title: A sum rule approach to the violation of Dashen's theorem

abstract:
  A classic sum rule by Das et al. is extended to seven of the low-energy
constants $K_i$, introduced by Urech, which parameterize electromagnetic
corrections at chiral order $O(e^2p^2)$. Using the spurion formalism, a simple
convolution representation is shown to hold and the structure in terms of the
chiral renormalization scale, the QCD renormalization scale and the QED gauge
parameter is displayed. The role of the resonances is studied as providing
rational interpolants to relevant QCD n-point functions in the euclidian
domain. A variety of asymptotic constraints must be implemented which have
phenomenological consequences. A current assumption concerning the dominance of
the lowest-lying resonances is shown clearly to fail in some cases.


title: Coulomb Effects on Charged Kaon Distributions From Vlasov Dynamics

abstract:
  We compute the influence of Coulomb effects on the charged kaon distribution
at low momentum in high energy nucleus-nucleus collisions. This is accomplished
by solving the Vlasov equation for the kaons in the presence of an expanding,
highly charged, fireball.


title: Summary of the Very Large Hadron Collider Physics and Detector Subgroup

abstract:
  We summarize the activity of the Very Large Hadron Collider Physics and
Detector subgroup during Snowmass 96.


title: Finite Temperature Wave-Function Renormalization, A Comparative Analysis

abstract:
  We compare two competing theories regarding finite temperature wave-function
corrections for the process $H \to e^+e^-$ and for $n+\nu \to p+e^-$ and
related processes of interest for primordial nucleosynthesis. Although the two
methods are distinct (as shown in $H \to e^+e^-$) they yield the same finite
temperature correction for all $n\to p$ and $p \to n$ processes. Both methods
yield an increase in the He/H ratio of .01% due to finite temperature
renormalization rather than a decrease of .16% as previously predicted.


title: The Octet Structure Function and Radiative Quarkonia Decay

abstract:
  The Operator Product Expansion, in conjunction with the power counting of
non-relativistic field theory, is used to examine the end-point region of the
radiative decay of heavy quark bound states with $^3S_1$ quantum numbers,
$Q\bar{Q}\rightarrow \gamma+X$. We identify an infinite class of operators that
determine the shape of the photonic end-point spectrum. These operators can be
resummed to form an octet structure function which parameterizes the energy of
the dynamical gluon content of the leading octet Fock state component of the
quarkonium. This color-octet contribution is important when the photon spectrum
is examined with a resolution given by $\Delta E_\gamma \sim m_Qv^2$, where
$v^2$ is the relative quark velocity squared. The formalism used makes explicit
the shift of the end-point from its partonic to its hadronic value.


title: Bound on nonlocal scale from g-2 of muon in a nonlocal WS model

abstract:
  We consider the nonlocal version of the Weinberg Salam model (following
Kleppe et al.) with a finite parameter $\Lambda$ signifying a fundamental
length scale.We calculate the extra contributions to the anomalous magnetic
moment of the muon coming from the nonlocal structure in this model.We find
that the nonlocal contribution can be comparable to weak contributions and goes
to increase theoretical estimates. We use this calculation to determine the
limit on the scale of nonlocality.We obtain the result $1/\Lambda \lessim 3
\times 10^{-16} $cm,which could be improved when present experimental errors
narrow down.


title:
TC corrections to the single-top-quark production at the Fermilab
  Tevatron

abstract:
  We calculate one-loop corrections to the single-top-quark production via
$q\overline{q}' \to t\overline b$ at the Fermilab Tevatron from the
Pseudo-Goldstone bosons ( PGBs ) in the framework of one generation technicolor
model. The maximum correction to the total cross section for the
single-top-quark production is found to reach -2.4% relative to the tree-level
cross section, which may be observable at a high-luminosity Tevatron.


title:
Role of the non-resonant background in the $\rho^0$-meson diffractive
  electro- and photoproproduction

abstract:
  The background due to the direct diffractive dissociation of the photon into
the $\pi^+\pi^-$-pair to the "elastic" diffractive $\rho^0$-meson production in
electron-proton collisions is calculated. The amplitude for the background
process $\gamma p \to \pi^+ \pi^- p$ is proportional to the $\pi$-meson -
proton cross section. Therefore, describing the HERA data, we can estimate
$\sigma (\pi p)$ at energy $s_{\pi p}\sim (2 - 3) \times 10^{3}$ GeV$^2$ that
is considerably higher the existing data. At large $Q^2$ the interference
between resonant and non-resonant $\pi^+ \pi^-$ production leads also to the
more slow increase of the $\sigma^L/\sigma^T$ ratio with the mass of the $2\pi$
(i.e. $\rho^0$-meson) state.


title:
Relations Among Correlation Functions in the High Temperature Phase of
  QCD with Broken SU(3)

abstract:
  Group-theoretic arguments are used to determine the dependence of two-point
correlators of quark bilinears on the current quark masses. The leading
difference between $\pi$ and $\delta$ correlators is found to be of order $m_s$
times a U(1)$_{\scriptscriptstyle A}$-violating correlator. These general
arguments are consistent with Schaefer's observation that if
U(1)$_{\scriptscriptstyle A}$ violation persists to high enough temperatures
then the strange $\eta$ can be lighter than the non-strange one.


title: Aspects of W Physics at the Linear Collider

abstract:
  It is argued that the next linear colliders can serve as W factories that may
be exploited for precision tests on the properties of the massive gauge bosons.
The connection between the probing of the symmetry breaking sector and precise
measurement of the self-couplings of the weak vector bosons is stressed. The
discussion relies much on the impact of the present low-energy data, especially
LEP1. These have restricted some paths that lead to the exploration of the
scalar sector through the investigation of the so-called anomalous couplings of
the W's and suggest a hierarchy in the classification of these parameters. The
limits we expect to set on these couplings at the different modes of the linear
colliders are reviewed and compared with those one obtains at the LHC. The
conclusion is that the first phase of a linear collider running at 500 GeV and
the LHC are complementary. Some important issues concerning radiative
corrections and backgrounds that need further studies in order that one
conducts high precision analyses at high energies are discussed.


title: Cutting rules in the real time formalisms at finite temperature

abstract:
  In this paper, we review the set of rules specific to the calculation of the
imaginary part of a Green's function at finite temperature in the real-time
formalisms. Emphasis is put on the clarification of a recent controversy
concerning these rules in the "1/2" formalism, more precisely on the issue
related to the interpretation of these rules in terms of cut diagrams, like at
T=0. On the second hand, new results are presented, enabling one to calculate
the imaginary part of thermal Green's functions in other formulations of the
real-time formalism, like the "retarded/advanced" formalism in which a lot of
simplifications occur.


title:
The Lightest Neutralino in Supersymmetric Standard Model with Arbitrary
  Higgs Sectors

abstract:
  We consider the neutralino mass matrix in a supersymmetric theory based on
SU(2) $\times$ U(1) gauge group with arbitrary number of singlet, doublet and
triplet Higgs superfields. We derive an upper bound on the mass of the lightest
neutralino, and a lower bound on the mass of the heaviest neutralino, in such a
theory. Assuming grand unification of the gauge couplings, the upper bound on
the mass of the lightest neutralino can be expressed in terms of the gluino
mass. For a gluino mass of 200 GeV, the tree level upper bound on the mass of
the lightest neutralino is 92 GeV, which increases to 166.5 GeV for a 1 TeV
gluino. We also discuss the effect of dominant one-loop radiative corrections
on these bounds.


title: Physical results by means of CompHEP

abstract:
  The CompHEP package was developed for calculations of decay and high energy
collision processes with, correspondingly, up to 5 and 4 final particles in the
lowest order (tree) approximation. The main idea put into CompHEP was to make
available passing from the Lagrangian to final distributions efficiently with
high level automation what is extremely needed in collider physics.
  The present talk describes a general structure of the CompHEP facilities and
reports some physical results obtained with its help. The main purpose of the
talk is to attract the attention of high energy physicists to this
user-friendly package which is completely aimed at making easier their routine
and tedious calculations in the TeV region.


title:
Non-local generalization of the axial anomaly and $x$-dependence of the
  anomalous gluon contribution

abstract:
  The generalization of the axial anomaly is considered. It is shown that
bilocal axial quark operators on the light cone possess, beside the point-like
anomaly, also a light-like anomaly. The consequences for the definition of
anomaly-free quark distribution functions and the effect of both gluon
coefficient function and splitting kernels in polarized deep inelastic
scattering are discussed.


title: Nonperturbative QCD Vacuum Effects in Nonlocal Quark Dynamics

abstract:
  A straightforward calculation reveals the essentially nonlocal character of
the leading heavy $Q\bar{Q}$ interaction arising from nonperturbative gluon
field correlations in the model of a fluctuating QCD vacuum. In light of this
quarkonium spin splitting ratio predictions which have supported the scalar
confinement ansatz are reconsidered as a specific example of possible
consequences for spectroscopy.


title: HQET chromomagnetic interaction at two loops

abstract:
  We present the coefficient of the chromomagnetic interaction operator, the
only unknown coefficient in the Heavy Quark Effective Theory (HQET) lagrangian
up to the $1/m$ level, with the two-loop accuracy by matching scattering
amplitudes of an on-shell heavy quark in an external field in full QCD and
HQET, and obtain the two-loop anomalous dimension of this operator in HQET.


title: Cosmic String Formation from Correlated Fields

abstract:
  We simulate the formation of cosmic strings at the zeros of a complex
Gaussian field with a power spectrum $P(k) \propto k^n$, specifically
addressing the issue of the fraction of length in infinite strings. We make two
improvements over previous simulations: we include a non-zero random background
field in our box to simulate the effect of long-wavelength modes, and we
examine the effects of smoothing the field on small scales. The inclusion of
the background field significantly reduces the fraction of length in infinite
strings for $n < -2$. Our results are consistent with the possibility that
infinite strings disappear at some $n = n_c$ in the range $-3 \le n_c < -2.2$,
although we cannot rule out $n_c = -3$, in which case infinite strings would
disappear only at the point where the mean string density goes to zero. We
present an analytic argument which suggests the latter case. Smoothing on small
scales eliminates closed loops on the order of the lattice cell size and leads
to a ``lattice-free" estimate of the infinite string fraction. As expected,
this fraction depends on the type of window function used for smoothing.


title: Dark Matter and the Scale of SUSY Breaking

abstract:
  We review the prospects for dark matter (DM) in two classes of supersymmetric
(SUSY) models which are characterized by the different mechanism of SUSY
breaking, namely the more common supergravity models with very large scale of
SUSY breaking and the recent schemes where SUSY is broken at a relatively low
scale and gravitinos are likely to be the lightest SUSY particle. We point out
that the former scheme is in general associated with the cold dark matter (CDM)
scenario, while the latter predicts a warm dark matter (WDM) dominated
Universe.


title: Low-Energy QCD and Ultraviolet Renormalons

abstract:
  We discuss the contribution of ultraviolet (UV) renormalons in QCD to
two-point functions of quark current operators. This explicitly includes
effects due to the exchange of one renormalon chain as well as two chains. It
is shown that, when the external euclidean momentum of the two-point functions
becomes smaller than the scale $\Lambda_L$ associated with the Landau
singularity of the QCD one-loop running coupling constant, the positions of the
UV renormalons in the Borel plane become true singularities in the integration
range of the Borel transform. This introduces ambiguities in the evaluation of
the corresponding two-point functions. The ambiguities associated with the
leading UV renormalon singularity are of the same type as the contribution due
to the inclusion of dimension d=6 local operators in a low-energy effective
Lagrangian valid at scales smaller than $\Lambda_L$. We then discuss the
inclusion of an infinite number of renormalon chains and argue that the
previous ambiguity hints at a plausible approximation scheme for low-energy
QCD, resulting in an effective Lagrangian similar to the one of the extended
Nambu-Jona-Lasinio (ENJL) model of QCD at large N_c.


title: The rapidity gap Higgs signal at LHC

abstract:
  We compare the WW and pomeron-pomeron fusion mechanisms for the
double-diffractive production of a Higgs boson. We determine the suppression of
the 'rapidity gap' pomeron-pomeron fusion events due to QCD radiative effects.
In particular we use leading log techniques to estimate the cross sections for
both exclusive and inclusive double-diffractive Higgs production at LHC
energies. The same approach can be applied to the double-diffractive central
production of large E_T dijets. These two processes provide one of the most
justified applications of various aspects of leading logarithm QCD techniques.


title: Neutrino Conversions in a Polarized Medium

abstract:
  Electron polarization induced by magnetic fields can modify the potentials
relevant for describing neutrino conversions in media with magnetic fields. The
magnitudes of polarization potentials are determined for different conditions.
We show that variations of the electron polarization along the neutrino
trajectory can induce resonant conversions in the active-sterile neutrino
system, but cannot lead to level crossing in the active-active neutrino system.
For neutrino flavour conversions the polarisation leads only to a shift of the
standard MSW resonance. For polarizations $\lambda \lsim 0.04$ the direct
modifications of the potential (density) due to the magnetic field pressure are
smaller than the modifications due to the polarization effect. We estimate that
indeed the typical magnitude of the polarization in the sun or in a supernova
are not expected to exceed $10^{-2}$. However even such a small polarization
may lead to interesting consequences for supernova physics and for properties
of neutrino signals from collapsing stars.


title: Perturbative QCD Approach to Multiparticle Production

abstract:
  In this review we discuss the analytical perturbative approach, based on
perturbative QCD and Local Parton Hadron Duality (LPHD), and its application to
multiparticle production in jets in the semisoft region. Analytical formulae
are presented for various observables within the accuracy of the Modified
Leading Logarithmic Approximation (MLLA), i.e. with terms of relative order
$\sqrt{\alpha_s}$ taken into account systematically, and in some cases with
even higher accuracy. These predictions are confronted with existing
experimental data. Many details of the perturbative approach to multiple
hadroproduction have been consolidated in recent years, and the overall picture
is remarkably healthy. The prospects of future studies of the semisoft jet
physics are also discussed.


title: Corrections to Sirlin's Theorem in $O(p^6)$ Chiral Perturbation Theory

abstract:
  We present the results of the first two-loop calculation of a form factor in
full $SU(3) \times SU(3)$ Chiral Perturbation Theory. We choose a specific
linear combination of $\pi^+, K^+, K^0$ and $K\pi$ form factors (the one
appearing in Sirlin's theorem) which does not get contributions from order
$p^6$ operators with unknown constants. For the charge radii, the correction to
the previous one-loop result turns out to be significant, but still there is no
agreement with the present data due to large experimental uncertainties in the
kaon charge radii.


title: Relic gravitational waves produced after preheating

abstract:
  We show that gravitational radiation is produced quite efficiently in
interactions of classical waves created by resonant decay of a coherently
oscillating field. For simple models of chaotic inflation in which the inflaton
interacts with another scalar field, we find that today's ratio of energy
density in gravitational waves per octave to the critical density of the
universe can be as large as 10^{-12} at the maximal wavelength of order 10^{5}
cm. In the pure $\lambda\phi^4$ model, the maximal today's wavelength of
gravitational waves produced by this mechanism is of order 10^6 cm, close to
the upper bound of operational LIGO and TIGA frequencies. The energy density of
waves in this model, though, is likely to be well below the sensitivity of LIGO
or TIGA at such frequencies. We discuss possibility that in other inflationary
models interaction of classical waves can lead to an even stronger
gravitational radiation background.


title:
Three-Jet Event Orientation in e+e- Annihilation: New Tests of the
  Standard Model

abstract:
  We discuss the orientation of e+e- -> q qbar g events in terms of the polar
and azimuthal angles of the event plane w.r.t. the electron beam direction. We
define an asymmetry of the azimuthal-angle distribution, which, along with the
left-right forward-backward polar-angle asymmetry, is sensitive to
parity-violating effects in three-jet events; these have yet to be explored
experimentally. We have evaluated these observables at O(alpha_s) in
perturbative QCD and present their dependence on longitudinal beam polarisation
and c.m. energy. We also define a moments analysis in terms of the orientation
angles that allows a new and more detailed test of QCD by isolating the six
independent helicity cross-sections.


title: Distinguishing Hybrids from Radial Quarkonia

abstract:
  We present arguments that reinforce the hybrid interpretation of pi(1800) and
we establish that the rho(1450) and the omega(1420) can be interpreted as
radial-hybrid mixtures. Some questions for future experiments are raised.


abstract:
  Large Rapidity Gap Events in Deep Inelastic Scattering are discussed in terms
of lightcone wave functions for quarks and gluons inside the photon. It is
shown that this approach is consistent with earlier, conventional Feynman
diagram calculations. An updated parametrization for the cross section is given
and a numerical analysis presented.


title: Upper Bound on R_b in Two Higgs Doublet Model from Lepton Universality

abstract:
  It has been known that $R_b$ can be enhanced in the two Higgs doublet model
if $\tan \beta$ is large. We point out that a similar enhancement in $\Gamma(Z
\to \tau^+ \tau^-)$ is large enough to place a constraint on such a
possibility. We obtain a 95% CL upper bound $\Delta R_b/R_{b} < 0.73%$ in this
model for the $\overline{MS}$ mass $m_{b} (m_{Z}) = 3.0$ GeV. The 1996 world
average is $\Delta R_{b}/R_{b}$ = $0.97% \pm 0.51%$. We used the $m_{b}(m_{Z})$
to determine the bottom Yukawa coupling instead of $m_b(m_{b})$ unlike in
previous analyses, and also an improved experimental test of the lepton
universality in $Z$ decay, which made our results qualitatively different.


title: Basics of QCD Perturbation Theory

abstract:
  This is an introduction to the use of QCD perturbation theory, emphasizing
generic features of the theory that enable one to separate short-time and
long-time effects. I also cover some important classes of applications:
electron-positron annihilation to hadrons, deeply inelastic scattering, and
hard processes in hadron-hadron collisions.


title: An extension of the standard model with a single coupling parameter

abstract:
  We show that it is possible to find an extension of the matter content of the
standard model with a unification of gauge and Yukawa couplings reproducing
their known values. The perturbative renormalizability of the model with a
single coupling and the requirement to accomodate the known properties of the
standard model fix the masses and couplings of the additional particles. The
implications on the parameters of the standard model are discussed.


title: Thermal Effects on Two-photon Decays of Pseudo-scalars

abstract:
  We study the effect of finite temperatures and Fermion density on the
effective pseudo-scalar-photon vertex induced by the triangle diagram. The
manifestly covariant calculations show that when the pseudo-scalar mass is much
less than the temperature, then there is a large enhancement of the decay rate.
Alternatively, when the temperature is much higher than the Fermion mass, or
the Fermion chemical potential is large, the lifetime is enhanced. Other
related processes, and applications of these results to cosmology and
astrophysics, are discussed.


title: Applicability constraints of the Equivalence Theorem

abstract:
  In this work we study the applicability of the Equivalence Theorem, either
for unitary models or within an effective lagrangian approach. There are two
types of limitations: the existence of a validity energy window and the use of
the lowest order in the electroweak constants. For the first kind, we consider
some methods, based on dispersion theory or the large $N$ limit, that allow us
to extend the applicability. For the second, we have obtained numerical
estimates of the effect of neglecting higher orders in the perturbative
expansion.


title: Distribution of valence quarks and light-cone QCD sum rules

abstract:
  A method for calculating the pion structure function directly in terms of
light-cone wave functions is suggested. Taking twist-2 and twist-4 pion
light-cone wave functions into account, it is shown that the QCD sum rule
prediction is in agreement with quark distribution obtained from analysis of
the Drell-Yan process. Twist-4 quark-gluon light-cone wave functions give a
large positive contribution to the pion structure function for x_B<0.2. A new
constraint on the twist-2 pion light-cone wave function is obtained. We argue
that the leading twist pion wave function \phi_\pi(u) \simeq 1 for u=0.3 with
an accuracy of about 20-30%.


title:
Anomalous triple gauge couplings in e+ e- -> W+ W- and "optimal"
  strategies for their measurement

abstract:
  We show how one can measure anomalous WWZ- and WWgamma-couplings with minimal
statistical error using integrated observables, without having to assume that
the anomalous couplings are small. We propose a parametrisation of these
couplings which is well suited for the extraction of both single and many
parameters, and which leads to a very simple form of the integrated cross
section, from which additional information on the couplings can be obtained.


title: Light cone QCD sum rule analysis of B -> K l(+) l(-) decay

abstract:
  We calculate the transition formfactors for the B -> K l(+) l(-) decay in the
framework of the light cone QCD sum rules. The invariant dilepton mass
distribution and the final lepton longitudinal polarization asymmetry are
investigated. The comparison analysis of our results with traditional sum rules
method predictions on the formfactors is performed.


title: Rho Meson Propagation and Dilepton Enhancement in Hot Hadronic Matter

abstract:
  A realistic model for the free rho meson with coupling to two-pion states is
employed to calculate the rho propagator in a hot and dense hadron gas. The
medium modifications are based on hadronic rescattering processes: intermediate
two-pion states are renormalized through interactions with surrounding nucleons
and deltas, and rho meson scattering is considered off nucleons, deltas, pions
and kaons. Constraints from gauge invariance as well as the full off-shell
dynamics of the interactions are accounted for. Within the vector dominance
model we apply the resulting in-medium rho spectral function to compute
$e^+e^-$ production rates from $\pi^+\pi^-$ annihilation. The calculation of
corresponding $e^+e^-$ spectra as recently measured in central collisions of
heavy-ions at CERN/SpS energies gives reasonable agreement with the
experimental data.


title: Antihydrogen

abstract:
  CERN announced in January 1996 the detection of the first eleven atoms of
antimatter ever produced. The experiment was based on a method proposed earlier
by S. Brodsky, C. Munger and I. Schmidt, and which furthermore predicted
exactly the number of atoms that were detected for the particular conditions of
the experiment. The study of antihydrogen affords science the opportunity to
continue research on the symmetry between matter and antimatter. In this talk
the importance of antihydrogen as a basic physical system is discussed.
Different production methods that have been tried in the past are briefly
presented, and the method that was used in the CERN experiment is analyzed in
detail. It consists in producing antihydrogen by circulating a beam of an
antiproton ring through an internal gas target. In the Coulomb field of a
nucleus, an electron-positron pair is created, and antihydrogen will form when
the positron is created in a bound rather that a continuum state about the
antiproton. The theoretical calculation of the production cross section is
presented in detail. A discussion of the detection systems used both in the
CERN experiment and in another similar experiment that is right now underway at
Fermilab are also given. Finally I present and discuss possible future
experiments using antihydrogen, including the measurement of the antihydrogen
Lamb shift.


title:
On the bounds for the curvature and higher derivatives of the Isgur-Wise
  function

abstract:
  We discuss constraints imposed on the zero-recoil curvature and higher
derivatives of the Isgur-Wise function by a general quark model. These
constraints are expressed as bounds for a given slope parameter, and compared
with those based upon analyticity properties of QCD spectral functions. Our
results also indicate that in the analysis of the experimental data for
semileptonic $B\rar D^{(*)}$ decays it may be important to include at least the
third term in the form factor expansion about the zero recoil point.


title:
The anomalous threshold, confinement, and an essential singularity in
  the heavy-light form factor

abstract:
  The analytic behavior of the heavy-light meson form factor is investigated
using several relativistic examples including unconfined, weakly confined, and
strongly confined mesons. It is observed that confinement erases the anomalous
threshold singularity and also induces an essential singularity at the normal
annihilation threshold. In the weak confinement limit, the "would be" anomalous
threshold contribution is identical to that of the real singularity on its
space-like side.


title: Supersymmetric Dynamical Generation of the Grand Unification Scale

abstract:
  The grand unification scale $M_{GUT}\sim 10^{16}$ GeV may arise from
dynamical effects. With the advances in understanding of supersymmetric
dynamics, we can break the grand unified group by introducing a strong gauge
group which generates the grand unification scale. We also show how this
mechanism can be combined with solutions to the doublet-triplet splitting
problem. The same method can also be used for other symmetry breakings at
intermediate scales as well.


title: Soft particle production in QCD jets

abstract:
  The perturbative QCD approach, based on Modified Leading Log Approximation
and Local Parton Hadron Duality, is shown to describe inclusive features of
multiparticle production in the soft region. Further predictions of this
approach are discussed.


title: Diffractive Heavy Quarkonium Photo- and Electroproduction in QCD

abstract:
  Hard diffractive photo- and electroproduction of heavy vector mesons
($J/\psi$ and $\Upsilon$) is evaluated within the leading $\alpha_s\ln{Q^2
\over\Lambda_{QCD}^2}$ approximation of QCD. In difference from our earlier
work on that subject, also the production of transversely polarized vector
mesons is calculated. Special emphasis is placed on the role of the vector
meson's $q\bar q$ light-cone wave function. In that context, conventional
non-relativistic quarkonium models and a light-front QCD bound state
calculation are critically examined and confronted with QCD expectations. Our
numerical analysis finds a significant high momentum tail in the latter wave
functions and a deviation from the expected asymptotic behavior of
$\phi_V(z,b=0)\propto z(1-z)$. We then design an interpolation to match the
quarkonium models at large inter-quark separations with QCD expectations at
small distances. We use these results to compare our predictions for the
forward differential cross section of $J/\psi$ photo- and electroproduction
with recent experimental results from HERA. In addition, our earlier discussion
of $\rho^o$ electroproduction is updated in light of recent experimental and
theoretical enhancements.


title:
Inflation, Topological Defects and Baryogenesis: Selected Topics at the
  Interface between Particles & Fields and Cosmology

abstract:
  Modern cosmology provides a connection between the physics of particles and
fields and observational cosmology. Making use of this link, a wealth of new
observational data can be utilized to explore and constrain theories of
fundamental physics. Inflationary Universe models and topological defect
theories are the most popular current paradigms for explaining the origin of
structure in the Universe. In these lectures, I discuss various aspects of
inflation and topological defects in which there has been interesting recent
progress or in which there are outstanding problems. Particular emphasis is
given to how baryogenesis scenarios can be influenced by inflation and
topological defects.


title:
Radiative Corrections to the Muonium Hyperfine Structure. II. The
  $\alpha (Z\alpha)^2 $ Correction

abstract:
  This is the second of a series of papers on the radiative corrections of
order $\alpha^2 (Z\alpha)$, $\alpha (Z\alpha )^2$, and various logarithmic
terms of order $\alpha^4$, to the hyperfine structure of the muonium ground
state. This paper deals with the $\alpha (Z\alpha)^2$ correction. Based on the
NRQED bound state theory, we isolated the term of order $\alpha(Z\alpha)^2$
exactly. Our result $+16.904 2 (11) \alpha(Z\alpha)^2 E_F / \pi$ for the
non-logarithmic part is consistent with the $\alpha (Z\alpha )^2$ part of
Sapirstein's calculation and the recent result of Pachucki, and reduces the
numerical uncertainty in the $\alpha (Z\alpha)^2$ term by two orders of
magnitude.


title: Dynamical generation of the constituent mass in expanding plasma

abstract:
  We investigate dynamics of the chiral transition in expanding quark-antiquark
plasma produced in an ultra-relativistic heavy ion collision. The chiral
symmetry break-down and dynamical generation of the constituent quark mass are
studied within the linear sigma model and Nambu-Jona-Lasinio model. Time
dependence of the quark and antiquark densities is obtained from the scaling
solution of the relativistic Vlasov equation. Fast initial growth and strong
oscillations of the constituent quark mass are found in the linear sigma model
as well as in the NJL model, when derivative terms are taken into account.


title: The proton and the photon, who is probing who?

abstract:
  It is shown that by assuming Gribov factorization to hold at low $x$ one
obtains a simple relation between the structure function of the proton and that
of the photon. By interpreting an observed structure in deep inelastic
scattering (DIS) of leptons on protons as belonging to the proton, one can
relate it to the structure of the exchanged photon, and visa versa. Predictions
are given for the structure function of real and virtual photons at low $x$ by
using data on the proton structure function together with the Gribov
factorization relations.


title: Topological Defects with Non-Symmetric Core

abstract:
  We demonstrate that field theories involving explicit breaking of continous
symmetries, incorporate two generic classes of topological defects each of
which is stable for a particular range of parameters. The first class includes
defects of the usual type where the symmetry gets restored in the core and
vacuum energy gets trapped there. We show however that these defect solutions
become unstable for certain ranges of parameters and decay not to the vacuum
but to another type of stable defect where the symmetry in not restored in the
core. In the wall case, initially spherical, bubble-like configurations are
simulated numerically and shown to evolve generically towards a planar
collapse. In the string case, the decay of the symmetric core vortex resembles
the decay of a semilocal string to a skyrmion with the important difference
that while the skyrmion is unstable and decays to the vacuum, the resulting
non-symmetric vortex is topologically stable.


title: The Weak-Magnetic Moment of Heavy Quarks

abstract:
  With initial and final particles on-shell, the anomalous weak-magnetic dipole
moments of b and c quarks are electroweak gauge invariant quantities of the
effective couplings Zb\bar{b} and Zc\bar{c}, respectively, and good candidates
to test the Standard Model and/or new physics. Here we present a complete
computation of these quantities within the Standard Model. We show that
decoupling properties with respect to heavy particles do take place in the weak
magnetic moment. The obtained values, a_b(M_Z^2)=(2.98-1.56i)x10^(-4) and
a_c(M_Z^2)=(-2.80+1.09i)x10^(-5) are dominated by one-gluon exchange diagrams.
The electroweak corrections are less than 1% of the total magnitude.


title: Recent Developments in Low x Physics

abstract:
  The QCD expectations for the behaviour of the deep inelastic scattering
structure functions in the region of small values of the Bjorken parameter $x$
are summarized. The Balitzkij, Lipatov, Fadin, Kuraev (BFKL) equation which
sums the leading powers of $\alpha_s ln(1/x)$ is described and confronted with
the "conventional" formalism based on the leading order QCD evolution
equations. The small $x$ behaviour of the spin dependent structure function
$g_1$ is also discussed. The dedicated measurements of the hadronic final state
in deep inelastic scattering at small $x$ probing the QCD pomeron are
described. This includes discussion of the deep inelastic scattering
accompanied by forward jets as well as production of forward prompt photons and
$\pi^0$-s. Finally the basic facts concerning the deep inelastic diffraction
are briefly summarized.


title: Running Inflation

abstract:
  A first order inflation model where a gauge coupling constant runs as the
universe inflates is investigated. This model can solve the graceful-exit
problem within Einstein gravity by varying the bubble formation rate. The
sufficient expansion condition gives group theoretical constraints on the
inflaton field, while the appropriate density perturbation requires an
additional scalar field or cosmic strings.


title: Introduction to the NRQCD Factorization Approach to Heavy Quarkonium

abstract:
  I present an introduction to the NRQCD factorization method for calculating
annihilation rates and inclusive production rates for heavy quarkonium. Using
this method, annihilation decay rates and sufficiently inclusive cross sections
are factored into long-distance NRQCD matrix elements and perturbative
short-distance coefficients. I derive the velocity-scaling rules that are used
to estimate the magnitudes of the nonperturbative NRQCD matrix elements and I
describe perturbative matching methods for calculating their short-distance
coefficients. Some simple applications for which NRQCD factorization methods
have dramatic implications are discussed.


title:
Neutral pion photoproduction on deuterium in baryon chiral perturbation
  theory to order q^4

abstract:
  Threshold neutral pion photoproduction on the deuteron is studied in the
framework of baryon chiral perturbation theory beyond next-to--leading order in
the chiral expansion. To fourth order in small momenta, the amplitude is finite
and a sum of two- and three-body interactions with no undetermined parameters.
With accurate theoretical and experimental input from the single nucleon sector
for the proton amplitude, we investigate the sensitivity of the threshold cross
section to the elementary $\gamma n \to \pi^0 n$ amplitude. A precise
measurement of the threshold cross section for $\gamma d \to \pi^0 d$ is called
for.


title: Probing Nucleon Spin Structure

abstract:
  One of the important questions in high energy physics is the relation of
quark and gluon spin to that of the nucleons which they comprise. Polarization
experiments provide a mechanism to probe the spin properties of elementary
particles and provide crucial tests of Quantum Chromodynamics (QCD). The
theoretical and experimental status of this fundamental question will be
reviewed in this paper.


title: Dispersive Approach to the Trace Anomaly

abstract:
  In the scalar $\phi^4$ field model the dispersive approach to the trace
anomaly is proposed. It is shown that it is impossible to get dispersion
representation for all formfactors so that preserve both the translation and
dilatation Ward identities. Subtractions which preserve energy-momentum
conservation violate the classical trace Ward--Takahashi identity and give rise
to an anomalous contribution to the matrix element of stress tensor
$\theta_\mu^\nu$. This contribution coincides with one-loop $\beta$-function in
accordance with previous analyses based on RG technique.


title:
Neutrino Mass Textures and the Nature of New Physics Implied by Present
  Neutrino Data

abstract:
  If all indications for neutrino oscillations observed in the solar,
atmospheric neutrino data as well as in the LSND experiments are borne out by
the ongoing and future experiments, then they severely constrain the neutrino
mass texture. In particular, the need for an ultralight sterile neutrino is
hard to avoid. Such ultralight neutrinos have profound implications not only
for physics beyond the standard model but also perhaps for physics beyond the
conventional grand unification. We discuss a scenario involving a parallel
universe that interacts with the familiar universe only via gravitational
interactions, where the ultralightness of the sterile neutrino follows from the
same physics that explains the near masslessness of the familiar neutrinos.


title:
Quarkonium production: velocity-scaling rules and long-distance matrix
  elements

abstract:
  The hierarchy of long-distance matrix elements (MEs) for quarkonium
production depends on their scaling with the velocity $v$ of the heavy quark in
the bound state. Ranges for the velocities in various bound states and
uncertainties of colour-singlet MEs are estimated in a quark-potential model.
Different possibilities for the scaling with $v$ of the MEs are discussed; they
depend on the actual values of $v$ and the QCD scale. As an application, J/psi
polarization in e^+e^- annihilation is discussed. The first non-perturbative
estimates of colour-octet MEs are presented and compared with phenomenological
determinations. Finally, various predictions of prompt quarkonium production at
LEP are compared.


title: Neutrinos and Physics Beyond the Standard Model

abstract:
  A brief sketch is made of the present observational status of neutrino
physics, with emphasis on the hints that follow from solar and atmospheric
neutrino observations, as well as cosmological data on the amplitude of
primordial density fluctuations. I also briefly review the ways to account for
the observed anomalies and some of their implications.


title: Nonlocal Condensates in QCD

abstract:
  In the presence of the nontrivial QCD ground state or vacuum, nonlocal
condensates are used to characterize the quark or gluon propagator, or other
Green functions of higher order. In this paper, we wish to show that, by taking
the large $N_c$ limit (with $N_c$ the number of color) in treating higher-order
condensates, a closed set of coupled differential equations may be derived for
nonlocal condensates. As a specific example, the leading-order equations for
the nonlocal condensates appearing in the quark propagator are derived and
explicit solutions are obtained. Some applications of our analytical results
are briefly discussed.


title:
Density and Boundary Effects on Pion Distributions in Relativistic
  Heavy--Ion Collisions

abstract:
  We compute the pion inclusive momentum distribution in a heavy-ion collision,
assuming thermal equilibrium and accounting for boundary effects at the time of
decoupling. We calculate the chemical potential corresponding to an average
pion multiplicity in central collisions and explore the consequences of having
the pion system produced close to the critical temperature for Bose-Einstein
condensation.


title:
Baryon asymmetry at the weak phase transition in presence of arbitrary
  CP violation

abstract:
  We consider interactions of fermions with the domain wall bubbles produced
during a first order phase transition. A new exact solution of the Dirac
equations is obtained for a wall profile incorporating a position dependent CP
violating phase. The reflection coefficients are computed, a resonance effect
is uncovered for rapidly varying phases. This resonance effect happens when the
energy and mass of the incident particles are $E/m=\Delta\theta/2$. Where
$\Delta\theta$ is the phase variation across the wall width. We calculate the
chiral charge flux through the wall surface and the corresponding baryon
asymmetry of the Universe. It agrees in sign and magnitude with the observed
baryonic excess $\rho_B/s\approx 10^{-10}$ for a large range of parameters and
CP violation. As a function of $\Delta\theta$, the ratio $\rho_b/s$ reach a
maximum for $\Delta\theta\approx 2-4\pi$ and $m\approx m_{top}$. PACS:
11.27.+d, 03.65.-w, 02.30.Hq, 02.30.Gp, 11.30.Fs, 98.80.Cq


title: A sensitive test for models of Bose-Einstein correlations

abstract:
  Accurate and sensitive measurements of higher order cumulants open up new
approaches to pion interferometry. It is now possible to test whether a given
theoretical prediction can consistently match cumulants of both second and
third order. Our consistency test utilizes a new technique combining
theoretically predicted functions with experimentally determined weights in a
quasi-Monte Carlo approach. Testing a general quantum statistics-based
framework of Bose-Einstein correlations with this technique, we find that
predictions for third order cumulants differ significantly from UA1 data. This
discrepancy may point the way to more detailed dynamical information.


title:
Soft-hard interplay and factorization for baryon production in the
  target fragmentation region in ep collisions

abstract:
  We discuss baryon production in the nucleon fragmentation region in deep
inelastic scattering. The dependence of the nucleon spectra on Bjorken-$x$ is
evaluated within the parton model and in QCD, and ways to look for the
break-down of the DGLAP approximation via baryon production are suggested. We
argue also that the leading neutron production in these small $x$ processes is
rather insensitive to the pion parton densities of the nucleon.


title: M-theory Inspired No-scale Supergravity

abstract:
  We propose a supergravity model that contains elements recently shown to
arise in the strongly-coupled limit of the $E_8\times E_8$ heterotic string
(M-theory), including a no-scale--like K\"ahler potential, the identification
of the string scale with the gauge coupling unification scale, and the onset of
supersymmetry breaking at an intermediate scale determined by the size of the
eleventh dimension of M-theory. We also study the phenomenological consequences
of such scenario, which include a rather constrained sparticle spectrum within
the reach of present-generation particle accelerators.


title: Non-leptonic B decays involving tensor mesons

abstract:
  Two-body non-leptonic decays of B mesons into PT and VT modes are calculated
using the non-relativistic quark model of Isgur et al.. The predictions
obtained for $B \to \pi D^*_2, \rho D_2^*$ are a factor of $3\sim 5$ below
present experimental upper limits. Interesting patterns are obtained for ratios
of B decays involving mesons with different spin excitations and their
relevance for additional tests of forms factor models are briefly discussed.


title: Double-Spin Transverse Asymmetries in Drell-Yan Processes

abstract:
  We calculate the double-spin transverse asymmetries for the Drell-Yan lepton
pair production in p-p and p-anti p collisions. We assume the transverse and
the longitudinal polarization densities to be equal at a very small scale, as
it is suggested by confinement model results. Using a global fit for the
longitudinal distributions, we find transverse asymmetries of order of 10^-2 at
most, in the accessible kinematic regions.


title: QCD Sum Rules and Vector Mesons in Nuclear Matter

abstract:
  Based on an effective Lagrangian which combines chiral SU(3) dynamics with
vector meson dominance, we have developed a model for the s-wave vector
meson-nucleon scattering amplitudes. We use this as an input for the low energy
part of the current-current correlation function in nuclear matter. Its
spectrum enters directly in the ``left hand side'' of QCD sum rules. For the
isovector channel we find a significant enhancement of the in-medium spectral
density below the $\rho$ resonance while the mass of $\rho$ meson itself
decreases only slightly. The situation is different in the isoscalar channel.
Here the mass and therefore the peak position of the $\omega$ meson decreases
strongly while the width increases less drastically than in the $\rho$ meson
case. For the $\phi$ meson we find almost no mass shift, the width of the peak
broadens due to the imaginary part of the scattering length. We find a
remarkable degree of consistency with the operator product expansion of QCD sum
rules in all three channels.


title: Structure Functions of Nuclei at Small x and Diffraction at HERA

abstract:
  Gribov theory is applied to investigate the shadowing effects in the
structure functions of nuclei. In this approach these effects are related to
the process of diffractive dissociation of a virtual photon. A model for this
diffractive process, which describes well the HERA data, is used to calculate
the shadowing in nuclear structure functions. A reasonable description of the
x, Q^2 and A-dependence of nuclear shadowing is achieved.


title:
Order \alpha_s^2 Contributions to charm production in charged-current
  deep-inelastic lepton-hadron scattering

abstract:
  The most important part of the order $\alpha_s^2$ corrections to the charm
component of the charged-current structure functions $F_2(x,Q^2)$ and
$F_3(x,Q^2)$ have been calculated. This calculation is based on the asymptotic
form of the heavy-quark coefficient functions corresponding to the higher order
corrections to the W-boson-gluon fusion process. These coefficient functions
which are in principle only valid for $Q^2 \gg m^2$ can be also used to
estimate the order $\alpha_s^2$ contributions at lower $Q^2$ values provided $x
< 0.1$. It turns out that the above corrections are appreciable in the large
$Q^2$-region and they explain the discrepancy found for the structure functions
between the fixed-flavour scheme (FFS) and the variable-flavour-number scheme
(VFNS). These corrections also hamper the extraction of the strange-quark
density from the data obtained for the charged-current and the
electromagnetic-current processes.


title:
Further Evidence for Threefold Maximal Lepton Mixing and a Hierarchical
  Spectrum of Neutrino Mass-Squared Differences

abstract:
  The phenomenological case for threefold maximal lepton mixing is strengthened
by more detailed comparison with existing data. The atmospheric neutrino data
are self-consistent and in good agreement with the threefold maximal mixing
prediction R = 2/3 (chi-squared/dof = 4.3/5, CL = 51%). Including partially
con- tained event data, the zenith angle dependence also points to threefold
maximal mixing, ruling-out a range of mixing schemes, including that of
Fritzsch and Xing. Accounting for `de facto' uncertainties in solar neutrino
fluxes, the solar neutrino data (including HOMESTAKE) are shown to be
consistent with threefold maximal mixing (chi-squared/dof = 5.1/3, CL = 16%),
as is the upper limit from the LSND appearance experiment. Detailed pred-
ictions for forthcoming long-base-line reactor and accelerator experiments are
presented.


title:
Preheating in an Expanding Universe: Analytic Results for the Massless
  Case

abstract:
  Analytic results are presented for preheating in both flat and open models of
chaotic inflation, for the case of massless inflaton decay into further
inflaton quanta. It is demonstrated that preheating in both these cases closely
resembles that in Minkowski spacetime. Furthermore, quantitative differences
between preheating in spatially-flat and open models of inflation remain of
order $10^{-2}$ for the chaotic inflation initial conditions considered here.


title: The static potential in QCD - a full Two-Loop Calculation

abstract:
  A full analytic calculation of the two-loop diagrams contributing to the
static potential in QCD is presented in detail. Using a renormalization group
improvement, the ``three-loop'' potential in momentum space is thus derived and
the third coefficient of the $\beta$-function for the V-scheme is given. The
Fourier transformation to position space is then performed, and the result is
briefly discussed.


title: Chiral Dynamics with Quark Degrees of Freedom

abstract:
  Possibility to detect DCC fluctuations is discussed. It is shown that
interactions with quark background and dissipative effects due to interactions
in the chiral field may result in damping of fluctuations. Since the magnitude
of fluctuations depends strongly on the initial state and speed of chiral phase
transition accurate evaluation of all modifying processes is required to
predict observability of DCCs.


title: Flavour-Dependent and Basis Independent Measures of R Violation

abstract:
  We construct lepton flavour-dependent and basis-independent measures of
R-parity violation in the minimal supersymmetric extension of the Standard
Model (MSSM). We work in the context of exact supersymmetry, neglecting the
effects of Higgs vacuum expectation values and soft supersymmetry-breaking
terms. We devote particular attention to appropriate choices of flavour
eigenstates, and to the counting and enumeration of R-violating invariants in
two- and three-generation models. We also make an indicative application of our
results to derive possible basis-independent cosmological upper bounds on
flavour-dependent violation of R parity.


title:
An Estimate of Charge Symmetry Breaking in Nuclear Deep Inelastic
  Scattering

abstract:
  We estimate the magnitude of charge symmetry breaking effects in deep
inelastic scattering from nuclei. The resulting contribution to systematic
uncertainties in hadronic determinations of $sin^2\theta_W$ are found to be
less than the current experimental accuracy, but may be important in the
analyses of more precise future experiments. We expect the largest nuclear
charge symmetry breaking effects in the Paschos-Wolfenstein ratio $R^-$, where
the resulting uncertainty in the determination of $sin^2 \theta_W$ reaches
$10^{-3}$.


title:
Four-quark final state in W-pair production: Case of signal and
  background

abstract:
  We discuss theoretical predictions for W-pair production and decay at LEP2
and higher energies in a form suitable for comparison with raw data. We present
a practical framework for calculating uncertainties of predictions given by the
KORALW and grc4f Monte Carlo programs. As an example we use observables in the
$s\bar s c\bar c$ decay channel: the total four-quark (four-jet) cross section
and two-quark/jet invariant-mass distribution and cross section, in the case
when the other two may escape detection. Effects of QED bremsstrahlung,
effective couplings, running W and Z widths, Coulomb interaction and the
complete tree level set of diagrams are discussed. We also revisit the question
of technical precision of the new version 1.21 of the KORALW Monte Carlo code
as well as of version 1.2(26) of the grc4f one.
  Finally we find predictions of the two programs to have an overall physical
uncertainty of 2%.
  As a side result we show, on the example of an $s\bar s$ invariant mass
distribution, the strong interplay of spin correlations and detector cut-offs
in the case of four-fermion final states.


title: Dynamical Nonsupersymmetry Breaking

abstract:
  We emphasize the role that anomalous power-law scaling of 4-fermion
operators, occurring in the presence of new strong interactions, could have in
the generation of quark and lepton masses.


title:
Quark-Antiquark Bound States within a Dyson-Schwinger Bethe-Salpeter
  Formalism

abstract:
  Pion and kaon observables are calculated using a Dyson-Schwinger
Bethe-Salpeter formalism. It is shown that an infrared finite gluon propagator
can lead to quark confinement via generation of complex mass poles in quark
propagators. Observables, including electromagnetic form factors, are
calculated entirely in Euclidean metric for spacelike values of bound state
momentum and final results are extrapolated to the physical region.


title:
Spin Dependent Drell-Yan beyond Leading Order: Non-Singlet Virtual
  corrections to $O(\alpha_s^2)$

abstract:
  We present parton-level analytical results for the next-to-leading order
non-singlet virtual and real corrections to the Drell-Yan differential
cross-section. The dependence of the differential cross section on the helicity
of the initial state partons is shown explicitly (the spins of the final state
partons are summed). The calculation is implemented in dimensional
regularization within the $\bar{MS}$ scheme and with the t'Hooft Veltman
prescriptions for the n-dimensional $\gamma_5$. Both the polarized initial
state and the unpolarized cross sections can be obtained from our result. Our
unpolarized cross section agrees with the previous result of Ellis, Martinelli
and Petronzio in the non-singlet sector.


title: Mass Matrix of Majorana Neutrinos

abstract:
  We present a massive Majorana neutrino model and see how it is constrained
from the solar and atmospheric neutrino deficit experiments. This model
incorporates the seesaw mechanism and Peccei-Quinn symmetry. Its consequence to
the neutrinoless double beta decay is also discussed.


title:
CP-Violating Reflection of High Energy Fermions during a first order
  Phase Transition

abstract:
  We study the high energy behaviour of fermions hitting a general wall caused
by a first-order phase transition. The wall profile is introduced through
general analytic and non-analytic functions. The reflection coefficient is
computed in the high energy limit and its connection with the analytic
properties of the wall profile function is shown. The high energy behaviour of
the fermions hitting the wall is determined either by the leading singularity,
i.e. the closest pole to the real axis, when the profile function is analytic,
or by the first non-continuous derivative on the real axis, in the non-analytic
case. CP-violating wall profiles are studied and it is shown that the
respective symmetry properties of the CP-conserving and CP-violating profile
functions plays an important role on the size of the CP asymmetry.


title: SU(5)+Adjoint Higgs Model at Finite Temperature

abstract:
  A three-dimensional effective theory of the finite-temperature SU(5)+adjoint
Higgs model is constructed using the method of dimensional reduction. The
resulting theory can be used for computer simulations of the GUT phase
transition of the early universe. In this paper the transition is analyzed at
two-loop level in perturbation theory. The structure of the effective theory
does not essentially depend on the matter contents of the original
four-dimensional one. Therefore the analysis of this paper applies also to more
realistic theories.


title: Production and polarization of $\Lambda_c^+$ and the charm of the proton

abstract:
  We propose a two-component model involving the parton fusion mechanism and
recombination of a $ud$ valence diquark with a sea $c$-quark of the incident
proton to describe $\Lambda_c^+$ inclusive production in $pp$ collisions. We
also study the polarization of the produced $\Lambda_c^+$ in the framework of
the Thomas Precession Model for polarization. We show that a measurement of the
$\Lambda_c$ polarization is a sensitive test of its production mechanism. In
particular the intrinsic charm model predicts a positive polarization for the
$\Lambda_c$ within the framework of the Thomas Precession Model, while
according to the model presented here the $\Lambda_c$ polarization should be
negative. The measurement of the $\Lambda_c$ polarization provides a close
examination of intrinsic charm Fock states in the proton and give interesting
information about the hadroproduction of charm.


title: The Charm of the Proton and the $\Lambda _c^{+}$ Production

abstract:
  We propose a two component model for charmed baryon production in $pp$
collisions consisting of the conventional parton fusion mechanism and
fragmentation plus quarks recombination in which a $ud$ valence diquark from
the proton recombines with a $c$-sea quark to produce a $\Lambda_c^+$. Our
two-component model is compared with the intrinsic charm two-component model
and experimental data.


title: The $\Lambda_0$ Polarization and the Recombination Mechanism

abstract:
  We use the recombination and the Thomas Precession Model to obtain a
prediction for the $\Lambda _0$ polarization in the $p+p \to \Lambda_0+X$
reaction. We study the effect of the recombination function on the $\Lambda_0$
polarization.


title: Lower bound for the ground state energy of the no-pair Hamiltonian

abstract:
  A lower bound for the ground state energy of a one particle relativistic
Hamiltonian - sometimes called no-pair operator - is provided.


title: Probing Flavor Changing Neutral Higgs Couplings at LHC

abstract:
  Uniquely heavy with mass at the weak scale, the top quark may have large
flavor changing couplings to Higgs bosons that are as yet unexplored. We show
that such couplings can be directly probed at the LHC through the parton
subprocess $c(\bar c)g \to t (\bar t)A^0$, where the pseudoscalar $A^0$
subsequently decays into $t \bar c$ or ${\bar t} c$, giving rise to the
intriguing final state of like sign top quark pairs. After demanding
$\ell^\pm\ell^\pm$, missing energy and two $b$-jets, the major background turns
out to be $q\bar q' \to Wt \bar t$, which can be partially suppressed by jet
counting. The signal can then manifest itself in the asymmetry of numbers of
$\ell^+\ell^+$ and $\ell^-\ell^-$ events. To further improve the signal over
background, efficient $t$ vs. $\bar t$ tagging methods should be developed.


title: Testing Extended Technicolor with R_b and Single Top Quark Production

abstract:
  We review the connection between m_t and the $Zb\bar b$ vertex in ETC models
and discuss how data on R_b constrains ETC models. Theories in which the ETC
and weak gauge groups do not commute are consistent with electroweak data and
predict effects on single top production that will be visible at Fermilab.


title: Large angle QED processes at e^+e^- colliders at energies below 3 GeV

abstract:
  QED processes at electron-positron colliders are considerd. We present
differential cross-sections for large-angle Bhabha scattering, annihilation
into muons and photons. Radiative corrections in the first order are taken into
account exactly. Leading logarithmic contributions are calculated in all orders
by means of the structure-function method. An accuracy of the calculation can
be estimated about 0.2%.


title: QCD corrections to the longitudinally polarized Drell-Yan process

abstract:
  In this paper we calculate the O($\alpha_s$) corrections to the $x_F$- and
$y$-distributions of lepton pairs produced in collisions of longitudinally
polarized hadrons. The numerical importance of these corrections is studied and
consequences for the extraction of the polarized sea quark distributions from a
measurement of the longitudinally polarized Drell-Yan cross section are
discussed.


title: CP Violation in the K and B Systems

abstract:
  Although CP violation was discovered more than thirty years ago, its origin
is still unknown. In these lectures, we describe the CP-violating effects which
have been seen in K decays, and explain how CP violation can be caused by the
Standard Model weak interaction. The hypothesis that this interaction is indeed
the origin of CP violation will be incisively tested by future experiments on B
and K decays. We explain what quantities these experiments will try to
determine, and how they will be able to determine them in a theoretically clean
way. To clarify the physics of the K system, we give a phase-convention-free
description of CP violation in this system. We conclude by briefly exploring
whether electric dipole moments actually violate CP even if CPT invariance is
not assumed.


title: Model-independent Constraints on Topcolor from $R_b$

abstract:
  We identify and compute the main corrections to $R_b$ in Topcolor theories.
They are due to the top-pions, the pseudo-Goldstone bosons associated with the
chiral symmetry breaking responsible for the top quark mass, and amount to
-(1-4)%, independent of the details of the Topcolor model. We show that the
cancellation of this effect against the contributions from Topcolor vector and
scalar resonances is unlikely, given the inherently distinct character of the
two scales governing the potentially cancelling terms. The resulting value of
$R_b$ leads to severe constraints on Topcolor theories.


title: Massive two--loop integrals in renormalizable theories

abstract:
  We propose a framework for calculating two-loop Feynman diagrams which appear
within a renormalizable theory in the general mass case and at finite external
momenta. Our approach is a combination of analytical results and of high
accuracy numerical integration, similar to a method proposed previously for
treating diagrams without numerators. We reduce all possible tensor structures
to a small set of scalar integrals, for which we provide integral
representations in terms of four basic functions. The algebraic part is
suitable for implementing in a computer program for the automatic generation
and evaluation of Feynman graphs. The numerical part is essentially the same as
in the case of Feynman diagrams without numerators.


title: Neutrino propagation in a random magnetic field

abstract:
  The active-sterile neutrino conversion probability is calculated for neutrino
propagating in a medium in the presence of random magnetic field fluctuations.
Necessary condition for the probability to be positive definite is obtained.
Using this necessary condition we put constraint on the neutrino magnetic
moment from active-sterile electron neutrino conversion in the early universe
hot plasma and in supernova.


title: Novel Algebraic Consequences of Chiral Symmetry

abstract:
  Phenomenologically motivated Lie-algebraic sum rules determine the
representations of unbroken SU(2)_L X SU(2)_R filled out by mesons containing a
single heavy quark, in the limit that the heavy quark mass goes to infinity.
This representation content determines the strong single-pion transition
amplitudes of all heavy meson states in the chiral limit. Predictions are found
to be in agreement with experiment, and provide insight into the spectroscopy
of heavy mesons.


title: Omega-Phi mixing at finite temperature

abstract:
  We compute the mass shifts and mixing of the Omega and Phi mesons at finite
temperature due to scattering from thermal pions. The Rho and b_1 mesons are
important intermediate states. Up to a temperature of 140 MeV the Omega mass
increases by 12 MeV and the Phi mass decreases by 0.6 MeV. The change in mixing
angles is negligible.


title: The KLN Theorem and Soft Radiation in Gauge Theories: Abelian Case

abstract:
  We present a covariant formulation of the Kinoshita, Lee, Nauenberg (KLN)
theorem for processes involving the radiation of soft particles. The role of
the disconnected diagrams is explored and a rearrangement of the perturbation
theory is performed such that the purely disconnected diagrams are factored
out. The remaining effect of the disconnected diagrams results in a simple
modification of the usual Feynman rules for the S-matrix elements. As an
application, we show that when combined with the Low theorem, this leads to a
proof of the absense of the $1/Q$ corrections to inclusive processes (like the
Drell-Yan process). In this paper the abelian case is discussed to all orders
in the coupling.


title: Asymptotic freedom in a scalar field theory on the lattice

abstract:
  An alternative model to the trivial $\phi^4$-theory of the standard model of
weak interactions is suggested, which embodies the Higgs-mechanism, but is free
of the conceptual problems of standard $\phi ^4$-theory. We propose a
N-component, O(N)-symmetric scalar field theory, which is originally defined on
the lattice. The model can be motivated from SU(2) gauge theory. Thereby the
scalar field arises as a gauge invariant degree of freedom. The scalar lattice
model is analytically solved in the large N limit. The continuum limit is
approached via an asymptotically free scaling. The renormalized theory evades
triviality, and furthermore gives rise to a dynamically formed mass of the
scalar particle.


title:
The Okubo relation for the baryon magnetic moments and chiral
  perturbation theory

abstract:
  We analyze the Okubo SU(3) relation among the hyperon magnetic moments in the
usual scheme of chiral perturbation theory (ChPT). We classify the one-loop
diagrams, including those with intermediate decuplet baryons, in a simple way
according to whether or not they satisfy the Okubo relation. Contrary to the
conventional wisdom, we find that one-loop contributions to the hyperon
magnetic moments in general violate the Okubo relation if the physical masses
are employed for the meson propagators in the loops.


title: The Transverse Momentum Dependence of Anomalous $J/\psi$ Suppression

abstract:
  In proton-nucleus and nucleus-nucleus collisions up to central $S-U$
interactions, the $P_T$-dependence of $J/\psi$ production is determined by
initial state parton scattering and pre-resonance nuclear absorption (``normal"
$J/\psi$ suppression). The ``anomalous" $J/\psi$ suppression in $Pb-Pb$
collisions must reduce the normal $P_T$ broadening, since it occurs mainly in
the central part of the interaction region, where also initial state parton
scattering and nuclear absorption are strongest. We thus expect for $< P_T^2 >$
in $Pb-Pb$ collisions a turn-over and decrease with increasing $E_T$.


title: Thermal hadron production in pp and p{\bar p} collisions

abstract:
  It is shown that the hadron production in high energy pp and p{\bar p}
collisions, calculated by assuming that particles originate in hadron gas
fireballs at thermal and partial chemical equilibrium, agrees very well with
the data. The temperature of the hadron gas fireballs, determined by fitting
hadron abundances, does not seem to depend on the centre of mass energy, having
a nearly constant value of about 170 MeV. This value is in agreement with that
obtained in e^+e^- collisions and supports a universal hadronization mechanism
in all kinds of reactions consisting in a parton-hadron transition at critical
values of temperature and pressure.


title: New Constraints on a Light Spinless Particle Coupled to Photons

abstract:
  We obtain new stringent constraints on a light spinless particle phi coupled
only to photons at low energies, considering its effects on the extragalactic
photon background, the blackbody spectrum of the CMBR and the cosmological
abundance of deuterium.


title: Bottom quark mass and alpha_s from the Upsilon system

abstract:
  The mass of the bottom quark and the strong coupling constant alpha_s are
determined from QCD moment sum rules for the Upsilon system. Two analyses are
performed using both the pole mass M_b as well as the mass m_b in the $\MSb$
scheme. In the pole-mass scheme large perturbative corrections resulting from
coulombic contributions have to be resummed. In the $\MSb$ scheme this can be
avoided by an appropriate choice for the renormalization scale. For the bottom
quark mass we obtain M_b = 4.60 +- 0.02 GeV and m_b(m_b) = 4.13 +- 0.06 GeV.
Our combined result from both determinations for the strong coupling is
alpha_s(M_Z) = 0.119 +- 0.008.


title: How Much of the Nucleon Spin is Carried by Glue?

abstract:
  We estimate in the QCD sum rule approach the amount of the nucleon spin
carried by the gluon angular momentum: the sum of the gluon spin and orbital
angular momenta. The result indicates that gluons contribute at least one half
of the nucleon spin at scale of 1 GeV^2.


title: K_L -> pi0 gamma e+ e- and its relation to CP and chiral tests

abstract:
  The decay K_L -> pi0 gamma e+ e- occurs at a it higher rate than the
nonradiative process K_L -> pi0 e+ e-, and hence can be a background to CP
violation studies using the latter reaction. It also has an interest in its own
right in the context of chiral perturbation theory, through its relation to the
decay K_L -> pi0 gamma gamma. The leading order chiral loop contribution to K_L
-> pi0 gamma e+ e-, including the [q(e+) + q(e-)]^2/m^2(pi) dependence, is
completely calculable. We present this result and also include the higher order
modifications which are required in the analysis of K_L -> pi0 gamma gamma.


title: Status of Supersymmetric Grand Unified Theories

abstract:
  We begin with a brief discussion of the building blocks of supersymmetric
grand unified theories. We recall some of the compelling theoretical reasons
for viewing supersymmetric grand unification as an attractive avenue for
physics beyond the standard model. This is followed by a discussion of some of
the circumstantial evidence for these ideas.


title: Quark Distribution Functions in a Diquark Spectator Model

abstract:
  The representation of quark distribution functions in terms of nonlocal
operators is combined with a simple diquark spectator model. This allows us to
estimate these functions for the nucleon ensuring correct crossing and support
properties.


title:
Asymmetries in polarized hadron production in e^+e^- annihilation up to
  order 1/Q

abstract:
  We present the results of the tree-level calculation of inclusive two-hadron
production in electron-positron annihilation via one photon up to subleading
order in 1/Q. We consider the situation where the two hadrons belong to
different, back-to-back jets. We include polarization of the produced hadrons
and discuss azimuthal dependences of asymmetries. New asymmetries are found, in
particular there is a leading cos(2 phi) asymmetry, which is even present when
hadron polarization is absent, since it arises solely due to the intrinsic
transverse momenta of the quarks.


title: Limitations of small x resummation methods from F_2 data

abstract:
  We discuss several methods of calculating the DIS structure functions
F_2(x,Q^2) based on BFKL-type small x resummations. Taking into account new
HERA data ranging down to small x and low Q^2, the pure leading order
BFKL-based approach is excluded. Other methods based on high energy
factorization are closer to conventional renormalization group equations.
Despite several difficulties and ambiguities in combining the renormalization
group equations with small x resummed terms, we find that a fit to the current
data is hardly feasible, since the data in the low Q^2 region are not as steep
as the BFKL formalism predicts. Thus we conclude that deviations from the
(successful) renormalization group approach towards summing up logarithms in
1/x are disfavoured by experiment.


title: Radiative neutrino decay in hot media

abstract:
  We calculate the rate for the radiative neutrino decay in a thermal
background of electrons and photons, taking into account the effect of the
stimulated emission of photons in the thermal bath. We show that the rate is
enhanced by a large factor relative to the rate for the corresponding process
in the vacuum.


title: Electromagnetic Catalysis of the Radiative Decay of the Axion

abstract:
  The radiative decay of the axion $a \to \gamma \gamma$ is investigated in an
external electromagnetic field in DFSZ model in which axion couples to both
quarks and leptons at tree level. The decay probability is strongly catalyzed
by the external field, namely, the field removes the main suppression caused by
the smallness of the axion mass.


title:
Resonance neutrino bremsstrahlung $\nu \to \nu \gamma$ in a strong
  magnetic field

abstract:
  High energy neutrino bremsstrahlung $\nu \to \nu + \gamma$ in a strong
magnetic field ($B \gg B_s$) is studied in the framework of the Standard Model
(SM). A resonance probability and a four-vector of the neutrino energy and
momentum loss are presented. A manifestation of the neutrino bremsstrahlung in
astrophysical cataclysm of type of a supernova explosion or a merger of neutron
stars, such as an possible origin of cosmological $\gamma$-burst is discussed.


title: Diffractive Higgs Production at the LHC

abstract:
  We use diffractive parton distributions obtained from fits to the diffractive
structure function measured at HERA to predict cross sections for single
diffractive Higgs production at the LHC. The dominant background processes are
also considered. Although some 5% - 15% of Higgs events are predicted to be
diffractive in this model, the ratio of signal to background is not
significantly improved.


title: Heavy-Quark Production

abstract:
  We review the present theoretical and experimental status of heavy quark
production in high-energy collisions. In particular, we cover hadro- and
photoproduction at fixed target experiments, at HERA and at the hadron
colliders, as well as aspects of heavy quark production in e+e- collisions at
the Z0 peak.


title: Elementary Processes in Dissipative Cosmic Medium

abstract:
  Quantum dynamics of a finite degrees of freedom is often much affected by
interaction with the larger environment of cosmic medium. In this lecture we
first review some recent developments of the theory of quantum dissipation in
the linear open system. In the second part we discuss two classes of
applications: decay of unstable particle in medium, and environmental effect on
the parametric particle production. The first subject of particle decay may
have important consequences on the scenario of baryogenesis due to a GUT heavy
particle. On the other hand, the parametric resonant particle production is
related to the reheating problem after inflation, and its environmental effect
is related also, perhaps more importantly, to the decay of moduli fields in
supergravity models.


title:
CP Asymmetries in Single Isospin Channels in B Decays and the Role of
  Inelastic Final State Interactions

abstract:
  The role of inelastic final state interactions in CP asymmetries is
investigated in single isospin two-body hadronic decays of the B meson. We
demonstrate that in a channel where the CP asymmetry vanishes in absence of
inelastic final state interactions, a coupling to a second channel where the
asymmetry is nonvanishing can result in an asymmetry in the first channel of
the same order as in the second.


title: Spin-Dependent Neutralino-Nucleus Scattering for $A \sim 127$ Nuclei

abstract:
  We perform nuclear shell model calculations of the neutralino-nucleus cross
section for several nuclei in the A = 127 region. Each of the four nuclei
considered is a primary target in a direct dark matter detection experiment.
The calculations are valid for all relevant values of the momentum transfer.
Our calculations are performed in the $3s 2d 1g_{7/2} 1h_{11/2}$ model space
using extremely large bases, allowing us to include all relevant correlations.
We also study the dependence of the nuclear response upon the assumed nuclear
Hamiltonian and find it to be small. We find good agreement with the observed
magnetic moment as well as other obervables for the four nuclei considered:
^{127}I, ^{129,131}Xe, and ^{125}Te.


title: New Messenger Sector for Gauge Mediated Supersymmetry Breaking

abstract:
  We propose a new class of gauge mediated supersymmetry breaking models where
the standard model gauge group is embedded into the gauge group $SU(2)_L\times
U(1)_{I_{3R}}\times U(1)_{B-L}$ [or $SU(2)_L\times SU(2)_R\times U(1)_{B-L}$]
at the supersymmetry breaking scale $\Lambda_S$. The messenger sector in these
models can consist of color singlet but $U(1)_{I_{3R}}$ and $U(1)_{B-L}$
nonsinglet fields. The distinguishing feature of these models are (i)exact
R-parity conservation, (ii) nonvanishing neutrino masses and (iii) a unified
hidden and messenger sector potential. The simplest version of these models
predicts the existence of light gluinos which can however be made heavier by a
simple modification of the supersymmetry breaking sector.


title: Constrained MSSM and the electric dipole moment of the neutron

abstract:
  We study the constraints on the CP-violating soft-breaking phases in the
minimal supersymmetric standard model using the limits on the chromoelectric
dipole moment of the strange quark extracted from the neutron EDM experiment.
Our investigation shows that the phase mediated by the gluino exchange diagram
has to be very small, $\phi\leq 8 10^{-4}$, for the common supersymmetric mass
of the order of 100 GeV. Then, solving the renormalization group equations
analytically by iterations, we calculate the electric dipole moment of the
neutron in the MSSM with CP-conserving soft-breaking parameters for the case of
three and four generations. For the three-generation case we resolve the
apparent discrepancies between order-of-magnitude estimates and numerical
calculations existing in the literature. In this case the EDM of the neutron
does not exceed $10^{-32} e cm$. For the four-generation case we show that
there is a significant enhancement which renders the EDM of the neutron at a
measurable level of $10^{-26}e cm$.


title:
The mixed quark-gluon condensate from an effective quark-quark
  interaction

abstract:
  We exhibit the method for obtaining non perturbative quark and gluonic vacuum
condensates from a model truncation of QCD. The truncation allows for a
phenomenological description of the quark-quark interaction in a framework
which maintains all global symmetries of QCD and allows an 1/N_c expansion.
Within this approach the functional integration over the gluon fields can be
performed and therefore any gluonic vacuum observable can be expressed in terms
of a quark operator and the gluon propagator. As a special case we calculate
the mixed quark gluon condensate. We investigate how the value depends on the
form of the model quark-quark interaction. A comparison with the results of
quenched lattice QCD, the instanton liquid model and QCD sum rules is drawn.


title: Suppression of PiNN(1535) Coupling in the QCD Sum Rule

abstract:
  The \pi NN^* and \eta NN^* coupling constants are studied in the QCD sum rule
($N^* \equiv N(1535)). We investigate the two point functions between the
vacuum and a one meson state in the soft meson limit. The operator product
expansion is explicitly performed up to terms of dimension eight. We find that
\gpNR vanishes to this order, while \geNR has a finite contribution. The
vanishing of \gpNR is a rigorous consequence in the chiral limit. The results
of the QCD sum rule are compared with those of low energy effective models.


title: String scale unification in an SU(6)xSU(2) GUT

abstract:
  We construct and analyze an $SU(6)\times SU(2)$ GUT. The model is k=1 string
embedable in the sense that we employ only chiral representations allowed at
the k=1 level of the associated Ka\v{c}-Moody Algebra. Both cases $SU(6)\times
SU(2)_{L}$ and $SU(6)\times SU(2)_{R}$ are realized. The model is characterized
by the $SU(6)\times SU(2) \to SU(4)\times SU(2)\times SU(2)$ breaking scale
$M_X$, and the $SU(4)\times SU(2)\times SU(2) \to SU(3)_{C}\times
SU(2)_{L}\times U(1)_{Y}$ breaking scale $M_{R}$ . The spectrum bellow $M_R$
includes an extra pair of charge-1/3 colour-triplets of mass $M_{I}\leq M_{R}$
that does not couple to matter fields and, possibly, an extra pair of
isodoublets. Above $M_{X}$ the SU(6) and SU(2) gauge couplings always unify at
a scale which can be taken to be the string unification scale $M_{s}\sim
5\times 10^{17} GeV$. The model has Yukawa coupling unification since quarks
and leptons obtain their masses from a single Yukawa coupling. Neutrinos obtain
acceptably small masses through a see-saw mechanism. Coloured triplets that
couple to matter fields are naturally split from the coexisting isodoublets
without the need of any numerical fine tuning.


title:
Charged-Current Leptoproduction of D-Mesons in the Variable Flavor
  Scheme

abstract:
  We present formulae for the momentum (z) distributions of D-mesons produced
in neutrino deep-inelastic scattering off strange partons. The expressions are
derived within the variable flavor scheme of Aivazis et al. (ACOT-scheme),
which is extended from its fully inclusive formulation to one-hadron inclusive
leptoproduction. The dependence of the results on the assumed strange quark
mass m_s is investigated and the m_ \to 0 limit is compared to the
corresponding MSbar results. The importance of O(alpha_s) quark-initiated
corrections is demonstrated for the m_s=0 case.


title: Towards Determining \phi_1 with B\to D^(*)\bar{D}^(*)

abstract:
  We present an isospin analysis of the decay modes B\to D\bar{D}, D^*\bar{D},
D\bar{D}^* and D^*\bar{D}^*, which allows determination of the final-state
interaction phases. As these transitions have branching ratios of the order
10^{-4} or larger, they could be useful in detecting the CP- violating phase
\phi_1 \equiv \arg (-V^*_{cb} V_{cd} V_{tb} V^*_{td} ) in the first-round
experiments of a B-meson factory. The problem of penguin pollution may still be
present. Once the Kobayashi-Maskawa matrix elements are known, it is possible
to obtain the magnitudes and relative phases of hadronic matrix elements for
B\to D^{(*)}\bar{D}^{(*)}. This will in turn lead to some information about the
penguin pollution.


title:
Muon-anti-neutrino <---> electron-anti-neutrino mixing: analysis of
  recent indications and implications for neutrino oscillation phenomenology

abstract:
  We reanalyze the recent data from the Liquid Scintillator Neutrino Detector
(LSND) experiment, that might indicate anti-nu_mu<--->anti-nu_e mixing. This
indication is not completely excluded by the negative results of established
accelerator and reactor neutrino oscillation searches. We quantify the region
of compatibility by means of a thorough statistical analysis of all the
available data, assuming both two-flavor and three-flavor neutrino
oscillations. The implications for various theoretical scenarios and for future
oscillation searches are studied. The relaxation of the LSND constraints under
different assumptions in the statistical analysis is also investigated.


title: Gauge-mediated SUSY Breaking at an Intermediate Scale

abstract:
  Gauge-mediated SUSY breaking with a messenger scale of order $10^{15}$ GeV
has some interesting features. It can solve the flavor changing neutral current
problem of supersymmetric models with predictions for superpartner masses which
are identical to those of minimal supergravity models. It can however also lead
to theories with novel experimental signatures. For example, we present a model
in which the gluino is the lightest supersymmetric particle. We also review the
present experimental status of a stable gluino.


title: Analyticity, Shapes of Semileptonic Form Factors, and B to pi l nu

abstract:
  We give a pedagogical discussion of the physics underlying dispersion
relation-derived parameterizations of form factors describing B -> pi l nu and
B -> D l nu. Moments of the dispersion relations are shown to provide
substantially tighter constraints on the f_+ (t) form factor describing B -> pi
l nu than the unweighted dispersion relation alone. Heavy quark spin symmetry
relations between the B -> pi l nu and B^* -> pi l nu form factors enables such
constraints to be tightened even further.


title: Light Gluino And Tevatroin Dijet Angular Distributions

abstract:
  We consider the effects of a light gluino on the dijet angular distributions
in p - pbar collisions at sqrt(s)=1800 GeV. We show that the slower running of
alpha_s and the production q qbar, g g -> Gino Gino do not significantly alter
the expected angular distributions. On the other hand, single U, D squark
production q g -> Q Gino with subsequent Q -> q g results in dijets whose
angular distributions are dramatically different from that in SM. The CDF data
on dijet angular distributions with integrated luminosity of 106 pb^(-1)
exclude U, D squarks in the mass ranges 170 < m < 650 and 190 < m < 600 GeV, We
consider lower energies as well and show that in a future experimental analysis
for dijet mass below 240 GeV squarks could be observed or ruled out.


title:
Chiral-loop and vector-meson contributions to eta -> pi pi gamma gamma
  decays

abstract:
  The process eta -> pi0 pi0 gamma gamma is discussed in Chiral Perturbation
Theory (ChPT) extending two recent analyses. Special attention is devoted to
one-loop corrections, eta-eta' mixing effects and vector-meson dominance of
ChPT counter-terms. The less interesting eta -> pi^+ pi^- gamma gamma
transition is briefly discussed too.


title: Kaon Polarizabilities in Chiral Perturbation Theory

abstract:
  We study the kaon polarizabilities in the framework of Chiral Perturbation
Theory to order $p^4$. For the neutral kaon we find that them vanish and they
have the first non-zero contribution to order $p^6$. We also emphasize the
theoretical potential of an eventual measuremnet of the kaon polarizabilities,
in particular of the neutral kaon ones.


title: Large-N supersymmetric beta-functions

abstract:
  We present calculations of the leading and O(1/N) terms in a large-N
expansion of the \beta-functions for various supersymmetric theories: a
Wess-Zumino model, supersymmetric QED and a non-abelian supersymmetric gauge
theory. In all cases N is the number of a class of the chiral superfields in
the theory.


title:
Dimension-six CP-conserving operators of the third-family quarks and
  their effects on collider observables

abstract:
  We list all possible dimension-six CP-conserving $SU_c(3)\times SU_L(2)
\times U_Y(1)$ invariant operators involving the third-family quarks which
could be generated by new physics at a higher scale. Expressions for these
operators after electroweak gauge symmetry breaking and the induced effective
couplings $Wt\bar b$, $Xb\bar b$ and $Xt\bar t$ $( X=Z,\gamma,g,H)$ are
presented. Analytic expressions for the tree level contributions of all these
operators to the observables $R_b$ and $A^b_{FB}$ at LEP I,
$\sigma(e^+e^-\rightarrow b\bar b)$ and $A^b_{FB}$ at LEP II,
$\sigma(e^+e^-\rightarrow t\bar t)$ and $A_{FB}^t$ at the NLC, as well as
$\sigma(p\bar p\rightarrow t\bar b+X)$ at the Tevatron upgrade, are provided.
The effects of these operators on different electroweak observables are
discussed and numerical examples presented. Numerical analyses show that in the
coupling region allowed by $R_b$ and $A^b_{FB}$ at LEP I, some of the new
physics operators can still have significant contributions at LEP II, the
Tevatron and the NLC.


title: Hadronic String from Confinement

abstract:
  The existence of hadronic string is derived as a consequence of confinement
in QCD. A state of ``stretched glue'', created by a Polyakov loop operator, is
shown to have translational zero-modes which are stringy degrees of freedom.
These modes are described by an effective string theory, valid for world-
sheets which are locally flat on length scales of order $\Lambda_{QCD}^{-1}$,
the dominant behavior being given by the Nambu-Goto action. In a subsequent
paper, these effective strings will be shown to emerge in mesons stretched by
their orbital angular momentum, thereby deriving some aspects of Regge
phenomenology directly from QCD and confinement.