title:
New Heavy Quark Limit Sum Rules involving Isgur-Wise Functions and Decay
  Constants

abstract:
  We consider the dominant $c\bar{c}$ contribution to $\Delta \Gamma$ for the
$B_s^0$-$\bar{B}_s^0$ system in the heavy quark limit for both $b$ and $c$
quarks. In analogy with the Bjorken-Isgur-Wise sum rule in semileptonic heavy
hadron decay, we impose duality between the parton model calculation of $\Delta
\Gamma$ and its estimation by a sum over heavy mesons. Varying the mass ratio
$m_c/m_b$ and assuming factorization and saturation by narrow resonances $(N_c
\to \infty$), we obtain new sum rules that involve the Isgur-Wise functions
$\xi^{(n)}(w)$ and $\tau^{(n)}_{1/2}(w)$ and the decay constants $f^{(n)}$,
$f^{(n)}_{1/2}$ ($n$ stands for any radial excitation). Alternatively, we
deduce the sum rules with another method free of the factorization hypothesis,
from the saturation of the expectation value of a product of two currents by
heavy hadrons and by the corresponding free quarks. The sum rules read
$\sum\limits_{n}{f^{(n)} \over f^{(0)}} \xi^{(n)}(w) = 2
\sum\limits_{n}{f^{(n)}_{1/2} \over f^{(0)}} \tau^{(n)}_{1/2}(w) = 1$, valid
for all $w$. Moreover, we obtain, in the heavy quark limit, $f^{(n)}_{3/2} =
0$. As a consequence, unlike the BIW sum rule, the slope of the elastic
function $\xi (w)$ is related to radial excitations alone. These are
generalizations, rigorous for QCD in the heavy quark limit, of results that
have an easy understanding in the non-relativistic quark model.


title:
Neutron Electric Dipole Moment from Supersymmetric Anomalous W-boson
  Coupling

abstract:
  In the supersymmetric standard model (SSM) the $W$-boson could have a
non-vanishing electric dipole moment (EDM) through a one-loop diagram mediated
by the charginos and neutralinos. Then the $W$-boson EDM induces the EDMs of
the neutron and the electron. We discuss these EDMs, taking into consideration
the constraints from the neutron and electron EDMs at one-loop level induced by
the charginos and squarks or sleptons. It is shown that the neutron and the
electron could respectively have EDMs of order of $10^{-26}e$cm and
$10^{-27}e$cm, solely owing to the $W$-boson EDM. Since these EDMs do not
depend on the values of SSM parameters for the squark or slepton sector, they
provide less ambiguous predictions for CP violation in the SSM.


title:
Dynamical determination of the top quark and Higgs masses in the
  Standard Model

abstract:
  We consider the application of the multiple point criticality principle to
the pure Standard Model, with a desert up to the Planck scale. According to
this principle, Nature should choose coupling constant values such that the
vacuum can exist in degenerate phases. Furthermore we require a strongly first
order phase transition between the two vacua, in order that the dynamical
mechanism be relevant. Thus we impose the constraint that the effective Higgs
potential should have two degenerate minima, one of which should have a vacuum
expectation value of order unity in Planck units. In this way we predict a top
quark mass of 173 +/- 4 GeV and a Higgs particle mass of 135 +/- 9 GeV. A
possible model to explain the multiple point criticality principle is the lack
of locality in quantum gravity and the effects of baby universes which, on
general grounds, are expected to make coupling constants dynamical.


title:
Lifetimes of quasiparticles and collective excitations in hot QED
  plasmas

abstract:
  The perturbative calculation of the lifetime of fermion excitations in a QED
plasma at high temperature is plagued with infrared divergences which are not
eliminated by the screening corrections. The physical processes responsible for
these divergences are the collisions involving the exchange of longwavelength,
quasistatic, magnetic photons, which are not screened by plasma effects. The
leading divergences can be resummed in a non-perturbative treatement based on a
generalization of the Bloch-Nordsieck model at finite temperature. The
resulting expression of the fermion propagator is free of infrared problems,
and exhibits a {\it non-exponential} damping at large times: $S_R(t)\sim
\exp\{-\alpha T t \ln\omega_pt\}$, where $\omega_p=eT/3$ is the plasma
frequency and $\alpha=e^2/4\pi$.


title: Chiral Perturbation Theory for DA$\Phi$NE Physics

abstract:
  This talk is an overview of Chiral Perturbation Theory for Kaon physics as
far as not covered by other speakers. It includes a short introduction to the
strengths and weaknesses of Chiral Perturbation Theory and its applications to
semileptonic Kaon decays and $K\to\pi\pi(\pi)$.


title: Relating CKM Parametrizations and Unitarity Triangles

abstract:
  Concise variable transformations between the four angles of the CKM matrix in
the standard representation advocated by the Particle Data Group and the angles
of the unitarity triangles are derived. The behavior of these transformations
in various limits is explored. The straightforward extension of this
calculation to other representations and more generations is indicated.


title: Z' Search in e+e- Annihilation

abstract:
  Expectations for constraints on extra Z bosons are derived for LEP 2 and
future linear e+e- colliders. For typical GUTs, a Z' with M_{Z'} \le 3 to 6
\sqrt{s} may cause observable effects. The Z' discovery limits are dominated by
statistical errors. However, if a Z' signal is observed, the discrimination
between different models becomes much worse if systematic errors are taken into
account. Discrimination between models is possible for M_{Z'} < 3 \sqrt{s}. A
determination of Z' f \bar f couplings independently of models becomes
attractive with future colliders. Anticipated bounds are determined.


title: Effects of an intermediate scale in SUSY grand unification

abstract:
  We discuss the production of lepton flavor violation and EDMs and the
viability of the $b-\tau$ unification hypothesis in SUSY grand unification with
an intermediate gauge symmetry breaking scale.


title: Topological Defects in $[SU(6)]^3 \times Z_3$

abstract:
  We study topological defects arising in the Grand Unification Model
$SU(6)_L\otimes SU(6)_c \otimes SU(6)_R \times Z_3$. We show that the model
does not contain domain walls, while it produces massive magnetic monopoles and
it may, depending on the symmetry breaking chain, give rise to the formation of
strings. We also discuss their possible relation$ the origin of the highest
energy cosmic rays detected.


title: A simple method for multi-leg loop calculations

abstract:
  In this paper, I present a technique to simplify the tensorial reduction of
one-loop integrals with arbitrary internal masses, but at least two massless
external legs. By applying the method to rank l tensor integrals, one ends up
with at most rank 1 tensor functions with the initial number of denominators,
plus tensor integrals with less denominators and rank < l. To illustrate the
algorithm, I explicitly compute diagrams contributing to processes of physical
interest and show how the usual numerical instabilities due to the appearance
of Gram determinants can be controlled.


title: Baryogenesis Through Mixing of Heavy Majorana Neutrinos

abstract:
  A mechanism is presented, in which the mixing of right handed heavy Majorana
neutrinos creates a $CP-$asymmetric universe. When these Majorana neutrinos
subsequently decay more leptons than anti-leptons are produced. The lepton
asymmetry created by this new mechanism can exceed by a few orders of magnitude
any lepton asymmetry originating from direct decays. The asymmetry is finally
converted into a baryon asymmetry during the electroweak phase transition.


title: Invariant analysis of CP violation

abstract:
  The invariant formulation of CP violation involves the generation of sets of
invariant constraints for CP conservation, the manipulation of their
expressions and the identification of complete and minimal subsets of such
constraints. In this paper we present a collection of subroutines to deal with
these three tasks in a fast, reliable and systematic way, with examples for the
leptonic sector.


title: A New Estimate of $\varepsilon '/\varepsilon$

abstract:
  We discuss a new estimate of $\varepsilon '/\varepsilon$ in the kaon system.
The present approach is based on the evaluation of the hadronic matrix elements
of the \mbox{$\Delta S =1$} effective quark lagrangian by means of the chiral
quark model, with the inclusion of meson one-loop renormalization and NLO
Wilson coefficients. The estimate here reviewed is fully consistent with the
$\Delta I =1/2$ selection rule in $K\to \pi\pi$ decays, which is well
reproduced within the same framework.


title: Numerical diagonalization of fermion mass matrices

abstract:
  The diagonalization of general mass matrices is a more delicate problem when
eigenvalue degeneracies exist. In this case, often overlooked in the
literature, some difficulties arise related to the freedom in the choice of
basis in degenerate subspaces. Here two simple algorithms are developed to deal
with quark and neutrino mass matrices with arbitrary degeneracies.


title: Heavy baryons in the relativistic quark model

abstract:
  In the framework of the relativistic quasipotential quark model the mass
spectrum of baryons with two heavy quarks is calculated. The quasipotentials
for interactions of two quarks and of a quark with a scalar and axial vector
diquark are evaluated. The bound state masses of baryons with
$J^P=\frac{1}{2}^+, \frac{3}{2}^+$ are computed.


title: Statistical Model for the Nucleon Structure Functions

abstract:
  A phenomenological model for the nucleon structure functions is presented.
Visualising the nucleon as a cavity filled with parton gas in equilibrium and
parametrizing the effects due to the finiteness of the nucleon volume, we
obtain a good fit to the data on the structure function $F_2^p$. The model then
successfully predicts other unpolarized structure function data.


title:
Effects of Final-State Interaction and Screening on Strange- and
  Heavy-Quark Production

abstract:
  Final-state interaction and screening have a great influence on $q \bar q$
production cross sections, which are important quantities in many problems in
quark-gluon plasma physics. They lead to an enhancement of the cross section
for a $q \bar q$ color-singlet state and a suppression for a color-octet state.
The effects are large near the production threshold. The presence of screening
gives rise to resonances for $q\bar q$ production just above the threshold at
specific plasma temperatures. These resonances, especially $c\bar c$ and $b
\bar b$ resonances, may be utilized to search for the quark-gluon plasma by
studying the temperature dependence of heavy-quark pair production just above
the threshold.


title:
WPHACT 1.0 - A program for $WW$, Higgs and 4 fermion physics at $e^+
  e^-$ colliders

abstract:
  WPHACT (W W and Higgs Physics with PHACT) is a MC program and unweighted
event generator which computes all Standard Model processes with four fermion
in the final state at $e^+ e^-$ colliders. It is based on an helicity amplitude
method which allows precise and fast evaluations of the matrix elements both
for massless and massive fermions. Fermion masses for $b$ quarks are exactly
taken into account. QED initial state and Coulomb corrections are evaluated,
while QCD final state corrections are included in an approximate formulation.
Cuts can be easily introduced and distributions for any variable at parton
level can be implemented. The contributions to the processes of neutral
Standard Model or Susy Higgs can be included. Anomalous couplings effects for
the triple coupling can be computed. An interface to hadronization is provided
and Jetset can be directly called from the program.


title: NLO calculations in QCD: a general algorithm

abstract:
  We briefly describe a new general algorithm for carrying out QCD calculations
to next-to-leading order in perturbation theory. The algorithm can be used for
computing arbitrary jet cross sections in arbitrary processes and can be
straightforwardly implemented in general-purpose Monte Carlo programs.


title:
The Lowest Order Hadronic Contribution to the Muon $g-2$ Value with
  Systematic Error Correlations

abstract:
  We have performed a new evaluation of the hadronic contribution to
$a_{\mu}=(g-2)/2$ of the muon with explicit correlations of systematic errors
among the experimental data on $\sigma( e^+e^- \to hadrons )$. Our result for
the lowest order hadronic vacuum polarization contribution is $ a_{\mu}^{had} =
702.6(7.8)(14.0) \times 10^{-10}$ where the the first error is statistical and
the second is systematic. The total systematic error contributions from below
and above $\sqrt{s} = 1.4$ GeV are $(13.1) \times 10^{-10}$ and $(5.1) \times
10^{-10}$ respectively, and are hence dominated by the low energy region.
Therefore, new measurements on $\sigma( e^+e^- \to hadrons )$ below 1.4 GeV can
significantly reduce the total error on $a_{\mu}^{had}$. In particular, the
effect on the total errors of new hypothetical data with 3 \% statistical and
0.5 - 1.0 \% systematic errors is presented.


title: Triple Pseudoscalar Decay Mode, $Z \to AAA$

abstract:
  We analyze the production of triple pseudoscalar Higgs bosons in the decay
channel of $Z\rightarrow AAA$ for light pseudoscalar bosons when the
corresponding scalar boson is too heavy to be produced by $Z$ decay. Analytic
results are obtained both at the tree level and at the one--loop level. The
branching fraction can be as large as $10^{-5}$ which should be detectable at
LEP.


title:
Search for Invisibly Decaying Higgs Bosons with the L3 Detector at the Z
  Pole

abstract: This paper has been withdrawn.


title:
Experimental Study of the Scalar-Top Discovery Potential using the L3
  Detector for LEP2

abstract: This paper has been withdrawn.


title: (S_3)^3 Theories of Flavor

abstract:
  I present a supersymmetric theory of flavor based on the discrete flavor
group $(S_3)^3$. The model can account for the masses and mixing angles of the
standard model, while maintaining sufficient sfermion degeneracy to evade the
supersymmetric flavor problem. I demonstrate that the model has a viable
phenomenology and makes one very striking prediction: the nucleon decays
predominantly to $K l$ where $l$ is a {\em first} generation lepton. I show
that the modes $n \rightarrow K^0 \bar{\nu}_e$, $p\rightarrow K^+ \bar{\nu}_e$,
and $p\rightarrow K^0 e^+$ occur at comparable rates, and could well be
discovered simultaneously at the SuperKamiokande experiment.


title: Prompt Charmonium Production in Z Decays

abstract:
  The color-evaporation model quantitatively describes all data on
photoproduction and hadroproduction of charmonium. Although the model is in
part nonperturbative, the associated parameters can for instance be determined
from the charmonium photoproduction data. At this point its predictions for the
prompt production of $\psi$'s at the $Z$ pole are made with no free parameters.
We show here that this approach successfully describes all data on the
production of prompt $\psi$'s in $Z$ decays.


title:
Search for Scalar Top Quarks with the L3 Detector at the Z Pole and at
  sqrts = 130 to 140 GeV

abstract: This paper has been withdrawn.


title: Supersymmetry at the electroweak scale

abstract:
  The simplest interpretation of the global success of the Standard Model is
that new physics decouples well above the electroweak scale. Supersymmetric
extension of the Standard Model offers the possibility of light chargino and
the right-handed stop (with masses below $M_Z$), and still maintaining the
successful predictions of the Standard Model. The value of $R_b$ can then be
enhanced up to $\sim 0.218$ (the Standard Model value is $\sim 0.216$). Light
chargino and stop give important contribution to rare processes such as
$b\rightarrow s \gamma$, $\overline K^0-K^0$ and $\overline B^0-B^0$ mixing but
consistency with experimental results is maintained in a large region of the
parameter space. The exotic four-jet events reported by ALEPH (if confirmed)
may constitute a signal for supersymmetry with such a light spectrum and with
explicitly broken $R-$parity. Their interpretation as pair production of
charginos with $m_C\sim 60$ GeV, with subsequent decay $C\rightarrow \tilde t_R
b \rightarrow dsb$ (where $m_{\tilde t}\sim 55$ GeV) leads to signatures very
close to the experimental observations.


title: Search for Charged Higgs Bosons with the L3 Detector at the Z Pole

abstract: This paper has been withdrawn.


title: A separate SU(2) for the third family: Topflavor

abstract:
  We consider an extended gauge group for the electroweak interaction: SU(2)_1
\times SU(2)_2 \times U(1)_Y where the first and second generations of fermions
couple to SU(2)_1 while the third generation couples to SU(2)_2. Bounds based
on precision observables and heavy gauge boson searchesare placed on the new
parameters of the theory, and the potential of the theory to explain R_b and
R_c is explored. We investigate processes that could produce observable signals
at the LHC and NLC.


title:
On Small-x Resummations for the Evolution of Unpolarized and Polarized
  Non--Singlet and Singlet Structure Functions

abstract:
  A brief survey is given of recent results on the resummation of leading
small-x terms for unpolarized and polarized non--singlet and singlet structure
function evolution.


title: Higgs Searches with the L3 Experiment at LEP2

abstract: This paper has been withdrawn.


title: Compositeness Condition for Dynamically Induced Gauge Theories

abstract:
  We show that the compositeness condition for the induced gauge boson in the
four-fermion interaction theory actually works beyond the one-loop
approximation. The next-to-leading contributions are calculated, and turn out
to be reasonably suppressed, so that the leading-order approximation is
justified.


title: Mesonic Form Factors and the Isgur-Wise Function on the Light-Front

abstract:
  Within the light-front framework, form factors for $P\to P$ and $P\to V$
transitions ($P$: pseudoscalar meson, $V$: vector meson) due to the
valence-quark configuration are calculated directly in the entire physical
range of momentum transfer. The behavior of form factors in the infinite quark
mass limit are examined to see if the requirements of heavy-quark symmetry are
fulfilled. We find that the Bauer-Stech-Wirbel type of light-front wave
function fails to give a correct normalization for the Isgur-Wise function at
zero recoil in $P\to V$ transition. Some of the $P\to V$ form factors are found
to depend on the recoiling direction of the daughter mesons relative to their
parents. Thus, the inclusion of the non-valence configuration arising from
quark-pair creation is mandatory in order to ensure that the physical form
factors are independent of the recoiling direction. The main feature of the
non-valence contribution is discussed.


title: Bottom production in hadronic collisions

abstract:
  I review the status of the comparison between theoretical predictions and
experimental results for bottom production in hadronic collisions, and discuss
the possible sources of the discrepancies found. The study of jets containing
bottom quarks is proposed as a promising tool to investigate the $b$ production
mechanism. I present next-to-leading order QCD predictions for this process,
and compare them with data.


title:
Inclusive production of hadrons in $\ell^\uparrow p^\uparrow \to
  h^\uparrow X$ and spin measurements

abstract:
  We discuss the production of polarized hadrons in polarized lepton nucleon
interactions and show that the helicity density matrix of the hadron, when
measurable, can give information on the spin structure of the nucleon and the
spin dependence of the quark fragmentation process. Single spin asymmetries in
the $\ell N^\uparrow \to hX$ process are also briefly discussed.


title: Fermion Scattering in domain walls with a locally dependent phase

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
phase factor. The reflection coefficients are obtained.


title:
Prospects for Measuring $\Delta g$ from Jets at HERA with Polarized
  Protons

abstract:
  The measurement of the polarized gluon distribution function $\Delta g(x)$
from photon gluon fusion processes in electron proton deep inelastic scattering
producing two jets has been investigated. The study is based on the MEPJET
simulation program. The size of the expected spin asymmetry and corresponding
statistical uncertainties for a possible measurement with polarized beams of
electrons and protons at HERA have been estimated. The results show that the
asymmetry can reach a few percents.


title: The Coleman-Weinberg Phase Transition in Extended Higgs Models

abstract:
  In Coleman-Weinberg symmetry breaking, all dimensionful parameters vanish and
the symmetry is broken by loop corrections. Before Coleman-Weinberg symmetry
breaking in the Standard Model was experimentally ruled out, it had already
been excluded on cosmological grounds. In this Brief Report, the cosmological
analysis is carried out for Coleman-Weinberg models with extended Higgs
sectors, which are not experimentally ruled out, and general constraints on
such models are given.


title:
Statistical Inspired Parton Distributions and the Violation of QPM Sum
  Rules

abstract:
  A quantum statistical parametrization of parton distributions has been
considered. In this framework, the exclusion Pauli principle connects the
violation of the Gottfried sum rule with the Ellis and Jaffe one, and implies a
defect in the Bjorken sum rule. However, in terms of standard parametrizations
of the polarized distributions a good description of the data is obtained once
a large gluon polarization is provided. Interestingly, in this description
there is no violation of the Bjorken sum rule.


title:
Hadronic interactions from effective chiral Lagrangians of quarks and
  gluons

abstract:
  Effective chiral Lagrangians involving constituent quarks, Goldstone bosons
and long-distance gluons are believed to describe the strong interactions in an
intermediate energy region between the confinement scale and the chiral
symmetry breaking scale. Baryons and mesons in such a description are bound
states of constituent quarks. We discuss the combined use of the techniques of
effective chiral field theory and of the field theoretic method known as
Fock-Tani representation to derive effective hadron interactions. The Fock-Tani
method is based on a change of representation by means of a unitary
transformation such that the composite hadrons are redescribed by
elementary-particle field operators. Application of the unitary transformation
on the microscopic quark-quark interaction derived from a chiral effective
Lagrangian leads to chiral effective interactions describing all possible
processes involving hadrons and their constituents. The formalism is
illustrated by deriving the one-pion-exchange potential between two nucleons
using the quark-gluon effective chiral Lagrangian of Manohar and Georgi. We
also present the results of a study of the saturation properties of nuclear
matter using this formalism.


title: Should the Strange Magnetic Moment of the Nucleon be Positive?

abstract:
  The strange magnetic moment of the nucleon ($\mu_s$) is examined as part of
the nucleon's isoscalar anomalous moment. The dominant up and down quark
effects in the anomalous moment may actually tend to favor $\mu_s >0$, which is
contrary to the negative values that generally result from model calculations.
The possible origins of this apparent discrepancy are considered.


title:
Multiple Point Criticality, Nonlocality, and Finetuning in fundamental
  physics: predictions for Gauge Coupling Constants gives
  $\alpha^{-1}=136._8\pm 9

abstract:
  The Multiple Point Criticality Principle (MPCP) states that action parameters
- in for example a field theory - take on values corresponding to the junction
of a maximum number of phases in the phase diagram of a system that undergoes
phase transitions. The phases to which physical significance is ascribed are
normally regarded as artifacts of a regulation procedure. In the context of a
Y-M lattice gauge theory, the MPCP is applied to the system of different
(Planck scale) lattice phases that can be provoked using a suitably generalised
action with a gauge group that is taken to be the Planck scale predecessor to
the Standard Model Group (SMG) - namely the $N_{gen}$-fold Cartesian product of
the SMG. Here $N_{gen}$ is the number of fermion generations. Ambiguities under
mappings of the gauge group $SGM^{N_{gen}}$ onto itself result in the Planck
scale breakdown to the diagonal subgroup which is isomorphic to the usual SMG.
Assuming the validity of the MPCP, the three SMG gauge couplings at the Planck
scale are predicted to be equal to the diagonal subgroup couplings correspond-
ing to the multiple point action parameters in a lattice gauge theory with the
gauge group $SMG^{N_{gen}}$. This prediction gives agreement with experiment to
within 10 \% for the non-Abelian couplings and 5\% for the U(1) gauge coup-
ling. In a more general context, the MPCP is proposed as a fundamental princi-
ple of Nature that can also explain other fine-tuning enigma in high energy
physics. It is argued that the MPCP implies having long range nonlocal inter-
actions which are identical between fields at all pairs of spacetime points.
Such interactions are allowed in a very general form of a reparameterization
invariant action. This phenomenologically unobjectionable form of nonlocality
would quite naturally be incorporated into our theory as constants of Nature.


title: A Multilepton signal for supersymmetric particles in Tevatron data?

abstract:
  The CDF and D0 collaborations have both reported unusual events in the
dilepton+jets sample with very high lepton and missing transverse energies. It
is possible, but very unlikely, that these events originate from top quark pair
production; however, they have characteristics that are better accounted for by
decays of supersymmetric quarks with mass in the region of 300 GeV: $\widetilde
q \to q \widetilde \chi$, $\widetilde\chi \to \nu\widetilde\ell$,
$\widetilde\ell\rightarrow \ell \widetilde \chi_1^0$. Such a supersymmetric
origin also leads to events with large transverse missing energy and either 0,
1, 2 same-sign, or 3 isolated leptons.


title: $b\to s\gamma$ and $\epsilon_1$ Constraints on Supergravity Models

abstract:
  In the light of the top quark discovered very recently by CDF, we investigate
the possibility of narrowing down the allowed top quark masses by combining for
the first time only two strongest constraints present in the no-scale
$SU(5)\times U(1)$ supergravity model, namely, the ones from the
flavor-changing radiative decay $b\rightarrow s\gamma$ and the precision
measurements at LEP in the form of $\epsilon_{1}$. It turns out that even
without including the most devastating constraint from $\Zbb$ measurement at
LEP in the form of $R_b$ directly or $\epsilon_b$ indirectly, the combined
constraint from $b\rightarrow s\gamma$ and $\epsilon_1$ alone in fact excludes
$m_t(m_t)\gsim 180\GeV$ altogether in the no-scale model, providing a
constraint on $m_t$ near the upper end of the CDF values. The resulting upper
bound on $m_t$ is stronger and $5 \GeV$ lower than the one from combining
$\epsilon_1$ and $\epsilon_b$ constraints and also combining $b\rightarrow
s\gamma$ and $\epsilon_b $ constraints in the previous analysis.


title: Effect of the unitary mixing scalar--vector

abstract:
  We consider the procedure of dressing of scalar and vector particles when
there exists the off--diagonal loop connecting vector and scalar propagators.
Instead of single Dyson equations for scalar and vector, we have in this case a
system of three equations for coupled full propagators. Using the $\pi-a_1$
system as an example, we discuss the physical meaning of this effect and the
renormalization procedure for coupled propagators. The considered effect of the
unitary S~--~V mixing may exits also in the "Higgs boson~--~Z~(~W~)" system for
extended electroweak models.


title: Cross-sections for squark and gluino production at hadron colliders

abstract:
  We present the cross-sections for the hadroproduction of squarks and gluinos
in next-to-leading order of supersymmetric QCD. The four possible final states
squark-antisquark, squark-squark, gluino-gluino and squark-gluino are analysed
for the hadron colliders Tevatron and LHC. The dependence of the cross-sections
on the renormalization and factorization scale is reduced significantly. The
shape of the transverse-momentum and rapidity distributions remains nearly
unchanged when the next-to-leading order SUSY-QCD contributions are included.
The size of the corrections at the central scale, given by the average mass of
the produced particles, varies between $+5\%$ and $+90\%$.


title: Density and Charge Fluctuations in Multiple Production

abstract:
  Oscillations of cumulant moments of multiplicity distributions at high ranks,
evolution of factorial moments with bin sizes (intermittency, fractality),
zeros of the truncated generating functions of multiplicity distributions, and
charge fluctuations in multiparticle production processes are discussed.


title: Momentum correlations in $Z^0\to b\bar b$ and the measurement of $R^0_b$

abstract:
  We study the correlations of $b\bar b$ pairs produced in inclusive $Z^0$
decays, and their possible influence upon the determination of $R_b$.


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

abstract:
  I review a recent attempt to reproduce the isospin $I= 0$ and 2 amplitudes
for the decay of a kaon into two pions by estimating the relevant hadronic
matrix elements in the chiral quark model. The results are parametrized in
terms of the quark and gluon condensates and of the constituent quark mass $M$.
The latter is a parameter characteristic of the model. For values of these
parameters within the current determinations, the $\Delta I= 1/2$ selection
rule is well reproduced by means of the cumulative effects of short-distance
NLO Wilson coefficients, penguin diagrams, non-factorizable soft-gluon
corrections and meson-loop renormalization.


title:
Final State Interactions, Resonances and CP Violation in D and B
  Exclusive Decays

abstract:
  Hadron resonances affect nonexotic $D^o$ decays but not $B$ decays which are
far from the resonance region. We obtain new information from {\bf exclusive}
decays and show that interference between colour favoured and colour suppressed
diagrams is {\bf constructive} in $B$ and (some) $D$ decays in contrast to the
inclusive decays where a net Pauli destructive interference is claimed. We
suggest that a systematic study of $B$ decay final states containing excited
mesons such as $a_1 D$ or $\pi D^{**}$ show opposite behaviour for $B^o$ and
$B^+$ relative to the ground state channels. We give inequalities among final
state branching ratios for several $B$ and $D$ channels. Decays into $\pi
K^{(*)}$ and $\rho K^{(*)}$ appear to show different behaviours.


title:
The neutrino mass and other possible signals of lepton-number violation
  in supersymmetric theories

abstract:
  We review a recently proposed framework in which the neutrino mass is a
signal of supersymmetry breaking and is suppressed dynamically. In addition, we
briefly comment on some possible consequences of general lepton-number
violation in supersymmetric theories, e.g., dijet and multijet signals and $jj
\rightarrow ll\gamma\gamma$.


title: Dispersion Relations and Effective Field Theory

abstract:
  The techniques of dispersion relations match very well with those of
effective field theory. I describe the techniques for using dispersion
relations effectively, and give some pedagogical examples to illustrate the
range of applications.


title: Final State Interactions in the Decays of Heavy Quarks

abstract:
  I discuss some recent results on the systematic behavior of final state
rescattering which makes use of the limit of a heavy B meson. The results
suggest that soft final state interactions do not disappear in the large $m_B$
limit. Soft and hard final state phases can both contribute to CP violating
asymmetries in B decay. The way that the soft phases occur is interesting
theoretically and suggests the violation of local quark-hadron duality.


title: Single-W production to test triple gauge boson couplings at LEP

abstract:
  We present a study of single-W production ($e^+e^-\to e^-\bar{\nu}_e W^+$) as
a new probe of the anomalous couplings at the LEP energy region. We introduce
simple cuts to separate the single-W process from W-pair production and have
performed cross-section calculations using 4-fermion generator ``grc4f''. The
cross-section of the single-W process is found to be large enough to detect at
LEP experiments in the near future. In addition, a high sensitivity to the
anomalous coupling of the $WW\gamma$ vertex is expected since the amplitude of
the $WW\gamma$ diagram makes a dominant contribution in this process. We have
found that the cross-section measurement of the single-W process in the LEP2
energy region can give complementary bounds on the anomalous couplings to those
obtained from W-pair analysis.


title: Tau mesonic decays and strong anomaly of PCAC

abstract:
  Strong anomaly of the PCAC is found in $\tau\rightarrow\omega \pi\pi\nu$ and
$\omega\rho\nu$ in the chiral limit. It originates in WZW anomaly. Theoretical
result of $\tau\rightarrow\omega\pi\pi\nu$ agrees with data well and the
measurement of $\tau\rightarrow\omega\rho\nu$ will confirm the strong anomaly
of PCAC. The strong anomaly of PCAC is studied.


title:
Radiative energy loss of high energy quarks and gluons in a finite
  volume quark-gluon plasma

abstract:
  The medium induced energy loss spectrum of a high energy quark or gluon
traversing a hot QCD medium of finite volume is studied. We model the
interaction by a simple picture of static scattering centres. The total induced
energy loss is found to grow as $L^2$, where $L$ is the extent of the medium.
The solution of the energy loss problem is reduced to the solution of a
Schr\"odinger-like equation whose ``potential'' is given by the
single-scattering cross section of the high energy parton in the medium. These
resuls should be directly applicable to a quark-gluon plasma.


title:
From hierarchical radiative quark mass matrices and mixings to FCNC in
  $SU(3)_c\times SU(2)_L\times U(1)_Y\times U(1)_H$

abstract:
  We present the realization of a mechanism that generates all mases and mixing
angles by using the top quark as seed in the context of an anomaly free abelian
extension of the standard model.


title:
BHAGEN-1PH: A Monte Carlo event generator for radiative Bhabha
  scattering

abstract:
  BHAGEN-1PH is a FORTRAN program providing fast Monte Carlo event generation
of the process $e^+ e^- \to e^+ e^- \gamma$, within electroweak theory, for
both unpolarized beams and also for the longitudinally polarized electron beam.
The program is designed for final leptons outside a small cone around the
initial leptons direction and has a new algorithm allowing also for a fast
generation of non collinear initial and final emission, as well as for
asymmetric and different angular cuts for final leptons.


title: Bhabha Process at LEP - Theoretical Calculations

abstract:
  In this contribution we give a short overview of the situation in the
precision calculation of the Bhabha process and we present a preliminary
numerical result on the second-order sub-leading correction to the small angle
Bhabha process.


title: The Stability of the Gauge Hierarchy in $SU(5) \times SU(5)$

abstract:
  It has been shown that the Dimopoulos-Wilczek (or missing-VEV) mechanism for
doublet-triplet splitting can be implemented in $SU(5) \times SU(5)$ models,
which requires no adjoint Higgs fields. This is an advantage from the point of
view of string theory construction. Here the stability of the gauge hierarchy
is examined in detail, and it is shown that it can be guaranteed much more
simply than in $SO(10)$. In fact a $Z_2$ symmetry ensures the stability of the
DW form of the expectation values to all orders in GUT-scale VEVs. It is also
shown that models based on $SO(10) \times SU(5)$ have the advantages of $SU(5)
\times SU(5)$ while permitting complete quark-lepton unification as in
$SO(10)$.


title:
Prospects for and Implications of Measuring the Higgs to Photon-Photon
  Branching Ratio at the Next Linear $e^+e^-$ Collider

abstract:
  We evaluate the prospects for measuring $BR(h\to\gamma\gamma)$ for a
Standard-Model-like Higgs boson at the Next Linear $e^+e^-$ Collider in the
$e^+e^-\to Z^*\to Z h$ and $e^+e^-\to\nu_e\anti\nu_e h$ production modes.
Relative merits of different machine energy/luminosity strategies and different
electromagnetic calorimeter designs are evaluated. We emphasize the importance
of measuring $BR(h\to\gamma\gamma)$ in order to obtain the total width of a
light Higgs boson and thereby the $b\anti b$ partial width that will be
critical in discriminating between the SM Higgs and the Higgs bosons of an
extended model.


title: Topologically nontrivial time-dependent chiral condensates

abstract:
  Topologically nontrivial time-dependent solutions of the classical nonlinear
sigma model are studied as candidates of the disoriented chiral condensate
(DCC) in 3+1 dimensions. Unlike the analytic solutions so far discussed, these
solutions cannot be transformed into isospin-uniform ones by chiral rotations.
If they are produced as DCC's, they can be detected by a distinct pattern in
the angle-rapidity distribution of the neutral-to-chrged-pion ratio.


title: A Realistic Supersymmetric Model with Composite Quarks

abstract:
  We describe a realistic, renormalizable, supersymmetric ``quindecuplet''
model in which the top quark, left handed bottom quark, and up-type Higgs boson
are composite, with a compositeness scale $\sim 1-3$ TeV. The top-Higgs Yukawa
coupling is a dynamically generated strong interaction effect, and is naturally
much larger than any other Yukawa coupling. The light quark doublets and
right-handed up-type quarks are also composite but at higher energies; the
hierarchy of quark masses and mixings is due to a hierarchy in the
compositeness scales. Flavor changing neutral currents are naturally
suppressed, as is baryon number violation by Planck-scale dimension five
operators. The model predicts that the most easily observable effects would be
on $b$-quark physics and on the $\rho$ parameter. In particular a small
negative $\Delta\rho=-\epsilon$ leads to $\Delta R_b> +2\epsilon$. There are
effects on $B$ meson mixing and on flavor-changing neutral-current $b$-quark
decays to leptons which might be detectable, but not on $b\rightarrow s\gamma$.
The model also suggests the supersymmetry-breaking mass for the right handed
top squark might be considerably larger than that of the left handed top
squark.


title: Problem of flavour in SUSY GUT and horizontal symmetry

abstract:
  The concept of non-abelian horizontal symmetry $SU(3)_H$ can greatly help in
understanding the fermion and sfermion flavour structures in supersymmetric
grand unification. For the sake of demonstration the $SU(5)\times SU(3)_H$
model, suggested earlier in ref. \cite{PLB85}, is revisited. We show that under
very simple and natural assumption it links the sfermion mass pattern to those
of fermions in a remarkable way. All dangerous supersymmetric flavour-changing
contributions are naturally suppressed in a general case, independently of the
concrete texture for fermion mass matrices. Nevertheless, within this framework
we present an example of predictive model for fermion masses and mixing, which
leads to 7 consistent predictions for the low energy observables. [Based on
talks given at Int. Workshop {\em `SUSY 96'}, Univ. of Maryland, 29 May - 1
June 1996 (to appear on Proceedings), and II US-Polish Workshop {\em `Physics
from Planck Scale to Electroweak Scale'}, Warsaw, 28-30 March 1996.]


title:
Transition rate for process involving particles with high momentum in a
  plasma and infrared physics for QED plasma

abstract:
  We derive a formula for computing the transition rate for a process involving
particles with momentum much higher than the temperature and chemical
potentials in a plasma by using an effective field theory approach. We apply it
to collision of charged particles with hard momentum inside a QED plasma. The
Debye screening effect and the damping of a charged particle moving in QED
plasma are studied. Using the Bloch-Nordsieck resummation, the infrared
divergences due to the absence of magnetic screening for QED plasma are shown
not to appear in physically measurable rates. The soft plasmon absorption and
emission for charged particles are discussed.


title:
On QCD $Q^2$-evolution of Deuteron Structure Function $F_2^D(x_D,Q^2)$
  for $x_D>1$

abstract:
  The deep-inelastic deuteron structure function (SF) $F_2^D(x_D,Q^2)$ in the
covariant approach in light-cone variables is considered. The $x_D$ and
$Q^2$-dependences of SF are calculated. The QCD analysis of generated data both
for non-cumulative $x_D<1$ and cumulative $x_D>1$ ranges was performed. It was
shown that $Q^2$-evolution of SF is valid for ranges $0.275<x_D<0.85$ and
$1.1<x_D<1.4$ for the same value of QCD scale parameter ${\Lambda}$. It was
found the $x_D$-dependence of SF for the ranges is essentially different.


title: Asymptotics of Heavy-Meson Form Factors

abstract:
  Using methods developed for hard exclusive QCD processes, we calculate the
asymptotic behaviour of heavy-meson form factors at large recoil. It is
determined by the leading- and subleading-twist meson wave functions. For $1\ll
|v\cdot v'|\ll m_Q/\Lambda$, the form factors are dominated by the Isgur--Wise
function, which is determined by the interference between the wave functions of
leading and subleading twist. At $|v\cdot v'|\gg m_Q/\Lambda$, they are
dominated by two functions arising at order $1/m_Q$ in the heavy-quark
expansion, which are determined by the leading-twist wave function alone. The
sum of these contributions describes the form factors in the whole region
$|v\cdot v'|\gg 1$. As a consequence, there is an exact zero in the form factor
for the scattering of longitudinally polarized $B^*$ mesons at some value
$v\cdot v'\sim m_b/\Lambda$, and an approximate zero in the form factor of $B$
mesons in the timelike region ($v\cdot v'\sim -m_b/\Lambda$). We obtain the
evolution equations and sum rules for the wave functions of leading and
subleading twist as well as for their moments. We briefly discuss applications
to heavy-meson pair production in $e^+ e^-$ collisions.


title: Electro-excitation amplitudes of the Delta-isobar in the Skyrme model

abstract:
  Electro magnetic transition form factors for the excitation of the
Delta33-resonance are evaluated in the Skyrme model. They crucially rely on
rotationally induced deformations of the hedgehog soliton which are suppressed
by two N_C-orders as compared to the leading parts of the isovector current.
Partial photon coupling through vector mesons is included in a schematic way.
Recoil corrections are approximated by a boost to the equal-velocity frame. The
results for the photodecay amplitudes agree with experimental numbers and the
shapes of M1, E2, C2 - transition form factors show essential features as
observed in electro-excitation experiments.


title: Finiteness in N=1 SYM Theories

abstract:
  I present a criterion for all-order finiteness in N=1 SYM theories. Three
applications are given; they yield all-order finite N=1 SYM models with global
symmetries of the superpotential.


title: Higgs Physics in the Large N limit

abstract:
  In this paper we study the large N limit of the Standard Model Higgs sector
with $N\lambda$, $Ng^2$ and $Ng'^2$ constant and $N$ being the number of
would-be Goldstone bosons. Despite the simplicity of this method at leading
order, its results satisfy simultaneously important requirements such as
unitarity and the low-energy theorems in contrast with other more conventional
approaches. Moreover, it is fully compatible with the Equivalence Theorem and
it yields a consistent description of the Higgs boson mass and width. Finally
we have also included a phenomenological discussion concerning the applications
of this method to the LHC.


title: New Parton Distribution Functions for the Photon

abstract:
  We present new improved parton distributions for the photon. We fit {\bf all}
available data on the photon structure function, $F^{\gamma}_{2}(x,Q^2)$, with
$Q^2\ge 3$ GeV$^2$, in order to determine the quark distributions. We also pay
particular attention to the gluon distribution in the photon,
$g^{\gamma}(x,Q^2)$, which has been poorly constrained in earlier analyses
which only include structure function data. We use large $p_T$ jet production
in $\gamma \gamma$ collisions from TRISTAN to constrain $g^\gamma $. We also
see what information can be gleaned from $\gamma p$ collisions at HERA on
$g^{\gamma}$ and on the quark distributions at large $x$, where there are no
structure function data. We review future prospects of elucidating the parton
distributions of the photon.


title:
On the indistinguishibility of Majorana- from Dirac-neutrino propagation
  in a stellar medium

abstract:
  We study, in the framework of the Standard Model, the propagation of (pure)
Majorana neutrinos in a typical stellar medium and show that Majorana neutrino
matter oscillations are completely indistinguishable from Dirac ones, even if
in the case of no family mixing Majorana neutrinos can be distinguished from
Dirac ones in the non-relativistic limit. Moreover, if CP violation is present,
an effective phase arises in the effective mixing matrix but, due to a symmetry
of the Majorana fields, this cannot be univocally determined


title:
Neutrino mass spectrum from the results of neutrino oscillation
  experiments

abstract:
  All the possible schemes of neutrino mixing with four massive neutrinos
inspired by the existing experimental indications in favor of neutrino mixing
are considered in a model independent way. Assuming that in short-baseline
experiments only one mass-squared difference is relevant, it is shown that the
scheme with a neutrino mass hierarchy is not compatible with the experimental
results. Only two schemes with two pairs of neutrinos with close masses
separated by a mass difference of the order of 1 eV are in agreement with the
results of all experiments. One of these schemes leads to possibly observable
effects in Tritium and neutrinoless double-beta decay experiments.


title: Soft Pomeron Physics on the Lattice

abstract:
  We discuss strategies for using lattice QCD to investigate some topics in
strong interaction phenomenology which are usually related to soft pomeron
exchange. These include hadronic cross-sections at high energies and
diffractive scattering at HERA. Some numerical results are presented in the
framework of the Landshoff-Nachtmann pomeron model.


title: Relativistic corrections to the positronium decay rate revisited

abstract:
  We rederive here in a simple and transparent way the master formula for the
dominant part of large relativistic corrections to the positronium decay rate.


title: Influence from the Future

abstract:
  We argue that some of the parameters in the laws of Nature would be well
understood, under the assumption that there is an influence from the future as
well as from the past, in the sense that the principle of locality is not valid
at the fundamental level. However, locality is supposed to be broken only in
the mild way that all the non-local influence comes from integrals over the
whole of space-time and acts at all moments and all places with the same
effect. Thus the observable effects of the lack of locality can only be seen in
the constants of Nature. Our cleanest prediction is the Higgs boson mass being
149 +/- 26 GeV, which in addition assumes that the pure Standard Model is valid
until the Planck scale. Adding the assumption that the two vacuum states needed
in our model come about naturally requires a strong first order transition
between them; together with the assumption of the Planck units being
fundamental, this leads us to also predict the top quark mass as 173 +/- 5 GeV,
and a more precise value of the Higgs boson mass as 135 +/- 9 GeV. With the
assumption of the anti-grand unified group SMG x SMG x SMG (three copies of the
Standard Model gauge group, one for each generation), it is also possible to
successfully predict the three fine structure constants in the Standard Model.
We also discuss the extension of the SMG x SMG x SMG group by an extra abelian
factor U(1)_f and the fermion mass matrices in this model. Other vacua than the
present one might appear in the future due to human activity. The breaking of
locality is really of the same mild character as suggested by baby universe
theory, so the present work may be considered as a development of baby universe
theory.


title: Charged Heavy Lepton Production In Superstring Inspired E6 Models

abstract:
  The possibility of studying superstring inspired \mbox{${\rm E}_6$}
phenomenology at high energy hadron colliders is investigated. A very simple
low energy rank-5 Supersymmetric (N=1) model is considered, which consists of
three scalar-Higgses, $H^0_{i=1,2,3}\,$, two charged-Higgses, $H^\pm\,$, one
pseudo-scalar-Higgses, $P^0\,$, and an extra vector boson, the $Z^\prime$. The
production of charged heavy leptons pairs, $L^+L^-\,$, by gluon-gluon fusion
and Drell-Yan mechanisms is discussed. For gluon-gluon fusion an enhancement in
the parton level cross-section is expected due to the heavy (s)fermion loops
which couple to the gluons. This mechanism is expected to dominate over
Drell-Yan for $L^+L^-$ invariant masses above the $Z^\prime$ mass.


title: The Interest of Large-t Elastic Scattering

abstract:
  Existing data for large-$t$ $pp$ elastic-scattering differential
cross-sections are energy-independent and behave as $t^{-8}$. This has been
explained in terms of triple-gluon exchange, or alternatively through
triple-singlet exchange. A discussion is given of the problems raised by each
of these explanations, and of the possibility that at RHIC or LHC energies the
exchange of three BFKL pomerons might result in a rapid rise with energy.


title:
Equivalence Between Vector Meson Dominance and Unitarised Chiral
  Perturbation Theory

abstract:
  It is explicitly shown that either the approximate solution of the integral
equation for the inverse of the pion form factor, or the result of the Pad\'e
approximant method of resumming the one loop Chiral Perturbation Theory (CPTH)
are equivalent to the standard vector meson dominance (VMD) models, using the
vector meson coupling to two pseudoscalars given by the KSRF relation.
Inconsistencies between the one loop CPTH and its unitarised version (or the
VMD model) are pointed out. The situation is better for the CPTH calculation of
the scalar form factor and the related S-wave $\pi \pi$ scattering. The
branching ratios of $\tau \to \pi^+ \pi^0 \nu$, $\tau \to K \pi \nu$, $\tau \to
K^+ \eta \nu$ and $\tau \to K^+ \bar{K^0} \nu$ using only two inputs as the
$\rho $ and $K^*$ masses, or the two corresponding rms radii, agree with the
experimental data. Using the same number of parameters, the corresponding one
loop CPTH calculation cannot explain the $\tau$ data.


title:
Detection of Neutral MSSM Higgs Bosons in Four-$b$ Final States at the
  Tevatron and the LHC: An Update

abstract:
  We update our earlier results regarding detection of $gg\to b\anti b h\to 4b$
($h=h^0,H^0,A^0$) to incorporate the very high $b$-tagging efficiencies and
purities that are now anticipated at the LHC. New results for the Tev$^*$ are
given, and indicate substantial potential for these modes. The complementarity
of the $H^0\to h^0h^0 \to 4b$ final state mode is illustrated for the LHC. The
latest radiative corrections to the Higgs sector are incorporated.


title: A Haplousterotic Model for the Nucleon Wave Function

abstract:
  We review the consequences of the sensitivity of the relation between the
moments of a model for the nucleon quark distribution amplitude and the
coefficients of its polynomial expansion. Criteria for a simpler approach to
constructing a model for the quark distribution amplitude are formulated. We
describe how such a simpler (or "haplousterotic") model for the quark
distribution amplitude of the nucleon is obtained from the QCD sum-rule moments
of COZ.


title:
Parton Distribution within Virtual Particles and $\gamma^{*}p$
  Interaction

abstract:
  A simple relativistic model is suggested that elucidates the qualitative
difference in valence quark distributions of bosons in ground and virtual
states. The inelastic diffraction of highly virtual photon in DIS is discussed.


title: Real-Time History of the Cosmological Electroweak Phase Transition

abstract:
  We study numerically the real-time history of the cosmological electroweak
phase transition, as it may take place in the Standard Model or in MSSM for m_H
< m_W according to recent lattice results. We follow the nucleated bubbles from
the initial stages of acceleration and rapid growth, through collisions with
compression waves resulting in slowing down and reheating to T_c, until the
final stages of slow growth and evaporation. We find that collisions with
compression waves may make the bubble walls oscillate in the radial direction,
and that reheating to T_c takes generically place.


title: Anomalous U(1) as a mediator of Supersymmetry Breaking

abstract:
  We point out that an anomalous gauge U(1) symmetry is a natural candidate for
being the mediator and messenger of supersymmetry breaking. It facilitates
dynamical supersymmetry breaking even in the flat limit. Soft masses are
induced by both gravity and the U(1) gauge interactions giving an unusual mass
hierarchy in the sparticle spectrum which suppresses flavor violations. This
scenario does not suffer from the Polonyi problem.


title: The Polarised $\Lambda$ production in QCD

abstract:
  The $Q^2$ evolution of polarised parton fragmentation functions is discussed
using Altarelli-Parisi evolution equations. The first moments of both polarised
quark and gluon fragmentation functions are shown to behave in a similar
fashion at very high energies. This analysis is applicable to any hard
processes involving production of polarised hadrons. The polarised $\Lambda$
hyperon production in $e^+~e^-$ annihilation where this can be realised is
considered. We present a complete $\alpha_s(Q^2)$ corrections to the
asymmetries discussed in the paper of Burkardt and Jaffe which demonstrates the
extraction of various polarised fragmentation functions. To this order, these
corrections are found to be scheme dependent similar to that of structure
functions.


title: Transverse structure function in the factorisation method

abstract:
  Deep Inelastic scattering experiments using transversely polarised targets
yield information on the structure function $g_2$. By means of a free-field
analysis, we study the operator structure of $g_2$ and demonstrate the need for
retaining the twist three mass terms in order to maintain current-conservation.
We show that the structure function $g_T=g_1+g_2$ has a much simpler operator
structure as compared to $g_2$, in spite of the fact that, like $g_2$, $g_T$
has a twist-three component. We demonstrate factorisation of the hadronic
tensor into hard and soft parts for the case of $g_T$. We show that the first
moment of the gluonic contribution to $g_T$ vanishes, and discuss possible
physical applications.


title: Melting of the Higgs Vacuum: Conserved Numbers at High Temperature

abstract:
  We discuss the computation of the grand canonical partition sum describing
hot matter in systems with the Higgs mechanism in the presence of non-zero
conserved global charges. We formulate a set of simple rules for that
computation in the high-temperature approximation in the limit of small
chemical potentials. As an illustration of the use of these rules, we calculate
the leading term in the free energy of the standard model as a function of
baryon number B. We show that this quantity depends continuously on the Higgs
expectation value $\phi$, with a crossover at $\phi\sim T$ where Debye
screening overtakes the Higgs mechanism---the Higgs vacuum ``melts". A number
of confusions that exist in the literature regarding the B dependence of the
free energy is clarified.


title: Form Factors for Exclusive Semileptonic $B$--Decays

abstract:
  We investigate the form factors for exclusive semileptonic decays of
$B$-meson to $D,~D^*$, based on the parton picture and helped by the results of
the HQET. We obtain the numerical results for the slope of the Isgur-Wise
function, which is consistent with the experimental results, and we extracte
the dependences of hadronic form factors on $q^2$ by varying input heavy quark
fragmentation function without the nearest pole dominance ans\"atze.


title:
Impact of squark pair decay modes on search for supersymmetric neutral
  Higgs bosons

abstract:
  We present a detailed study of the decays of the neutral Higgs bosons $H^0$
and $A^0$ within the Minimal Supersymmetric Standard Model. We find that the
supersymmetric modes ${\tilde{t}}\bar{\tilde{t}}$ and
${\tilde{b}}\bar{\tilde{b}}$ can dominate the $H^0$ and $A^0$ decays in a wide
range of the model parameters due to large Yukawa couplings and mixings of
${\tilde{t}}$ and ${\tilde{b}}$. Compared to the conventional modes $t\bar{t}$
and $b\bar{b}$, these modes have very distinctive signatures. This could have a
decisive impact on the neutral Higgs boson searches at future colliders.


title: $B\to X_s\tau^+\tau^-$ in a two Higgs doublet model

abstract:
  The inclusive rate and forward-backward asymmetry of dilepton angular
distribution for a B-meson to decay to strange hadronic final states and a
$\tau^+\tau^-$ pair in a two Higgs doublet model are computed. In particular,
contributions of neutral Higgs bosons to the decay are included. QCD
corrections to the effective Hamiltonian for $B\rightarrow X_s\tau^+\tau^-$ are
calculated using the leading logarithmic approximation.


title:
Discovery limits for a new contact interaction at future hadronic
  colliders with polarized beams

abstract:
  The production of high-transverse energy jets in hadron-hadroncollisions is
sensitive to the presence of new contact interactions between quarks. If proton
polarization were available, the measurement of some parity violating spin
asymmetries in one-jet production at large transverse energy would complement
the usual search for deviations from the expected QCD cross section. In the
same time, a unique information on the chirality structure of the new
interaction could be obtained. In this context, we compare the potentialities
of various $pp$ and $p\bar p$ colliders that are planned or have been proposed,
with the additional requirement of beam polarization.


title: Neutrino Physics: Fundamentals of Neutrino Oscillations

abstract:
  In this lecture we review some of the basic properties of neutrinos, in
particular their mass and the oscillation behavior. First we discuss how to
describe the neutrino mass. Then, under the assumption that neutrinos are
massive and mixed, the fundamentals of the neutrino oscillations are discussed
with emphasis on subtle aspects which have been overlooked in the past. We then
review the terrestrial neutrino oscillation experiments in the framework of
three generations of neutrinos with the standard mass hierarchy. Finally, a
brief summary of the current status of the solar and atmospheric neutrino
problems will be given.


title: CP Violation and Flavour Mixing in the Standard Model -- 1996 Update

abstract:
  We review and update the constraints on the parameters of the quark flavour
mixing matrix $V_{CKM}$ in the standard model and estimate the resulting CP
asymmetries in $B$ decays, taking into account recent experimental and
theoretical developments. With the updated CKM matrix we present the
currently-allowed range of the ratios $|V_{td}/V_{ts}|$ and $|V_{td}/V_{ub}|$,
as well as the standard model predictions for the \bsbsbar\ mixing parameter
$\xs$ (or, equivalently, $\delms$) and the quantities $\sin 2\alpha$, $\sin
2\beta$ and $\sin^2\gamma$, which characterize the CP-asymmetries in
$B$-decays.


title: HERWIG version 5.9

abstract:
  HERWIG (Hadron Emission Reactions With Interfering Gluons) is a multipurpose
Monte Carlo event generator for the simulation of hard collisions between
hadrons, leptons and photons. This note describes the new features of version
5.9. These include adding over 100 new particles, 1800 new decay modes and
supporting new decay types. A complete space-time picture, including heavy
meson mixing and secondary decays, is available for all event types and
includes an optional colour rearrangement model. Initial state radition of
photons in e^+e^- is is now included. Many other processes and features have
been upgraded.


title: The More Minimal Supersymmetric Standard Model

abstract:
  Effective Supersymmetry is presented as a theory of physics above the
electroweak scale which has significant theoretical advantages over both the
standard model and the Minimal Supersymmetric Standard Model (MSSM). The theory
is supersymmetric at short distances but differs significantly from the MSSM.
Flavor symmetry violation is intimately related to supersymmetry breaking.
There is a new physics scale $\mt\sim$~5--20 TeV which sets the mass of the
first two sparticle families. Supersymmetric sources of CP violation and flavor
changing neutral currents for the first two families are suppressed. Effective
Supersymmetry can be implemented with automatic suppression of baryon and
lepton number violation and a dynamically generated $\mu$ term, while
maintaining naturalness in the Higgs sector. There are implications for new
particle searches, flavor and CP violation experiments, as well as for the
construction of theories of flavor and dynamical supersymmetry breaking.


title:
On the Possibility to Study Color Transparency in the Large Momentum
  Transfer Exclusive $d(p,2p)n$ Reaction

abstract:
  The deuteron disintegration at high energies and large angles in the
$d(p,2p)n$ reaction, is calculated in kinematical conditions where the dominant
contributions are due to soft rescatterings of the initial and final nucleons,
which accompany the hard $pp$ reaction. The eikonal approximation, which
accounts for relativistic kinematics as dictated by Feynman diagrams, reveals
the important role played by the initial and final state interactions in the
angular and momentum dependences of the differential cross section. Based on
these results, we propose a new and effective test, at moderate energies, of
the physics relevant for the color transparency phenomenon in hadron-initiated
exclusive hard processes.


title: Supersymmetry Breaking and Fermi Balls

abstract:
  A simple model is presented where the disappearance of domain walls and the
associated production of ``Fermi balls'', which have been proposed as
candidates for cold dark matter, are features which arise rather naturally in
response to softly broken supersymmetry.


title: Variations on Minimal Gauge Mediated Supersymmetry Breaking

abstract:
  We study various modifications to the minimal models of gauge mediated
supersymmetry breaking. We argue that, under reasonable assumptions, the
structure of the messenger sector is rather restricted. We investigate the
effects of possible mixing between messenger and ordinary squark and slepton
fields and, in particular, violation of universality. We show that acceptable
values for the $\mu$ and $B$ parameters can naturally arise from discrete,
possibly horizontal, symmetries. We claim that in models where the
supersymmetry breaking parameters $A$ and $B$ vanish at tree level, $\tan\beta$
could be large without fine tuning. We explain how the supersymmetric CP
problem is solved in such models.


title:
Heavy Isovector Resonances in e^+e^- annihilation, in the decay
  J/psi-->pi^+pi^-pi^0 and in the reaction K^-p-->pi^+pi^-Lambda

abstract:
  The results of an analysis are presented of some recent data on the reactions
$e^+e^-\to\pi^+\pi^-\pi^+\pi^-$, $e^+e^-\to\pi^+\pi^-\pi^0\pi^0$ with the
subtracted $\omega\pi^0$ events, $e^+e^-\to\omega\pi^0$, $e^+e^-\to\eta
\pi^+\pi^-$, $e^+e^-\to\pi^+\pi^-$, $J/\psi\to\pi^+\pi^-\pi^0$ and
$K^-p\to\pi^+\pi^-\Lambda$, upon taking into account both the strong energy
dependence of the partial widths on energy and the previously neglected mixing
of the $\rho$ type resonances. The above effects are shown to exert an
essential influence on the specific values of masses and coupling constants of
heavy resonances and hence are necessary to be accounted for in establishing
their true nature.


title: Subleading Reggeons in Deep Inelastic Diffractive Scattering at HERA

abstract:
  The contribution of subleading reggeons to the diffractive structure function
${dF_{2}^D / dx_{\funp} dt}$ is estimated from the soft physics data. This
contribution leads in a natural way to the violation of the factorization
property of the diffractive structure function.


title: New limits on the mass of neutral Higgses in General Models

abstract:
  In general electroweak models with weakly coupled (and otherwise arbitrary)
Higgs sector there always exists in the spectrum a scalar state with mass
controlled by the electroweak scale. A new and simple recipe to compute an
analytical tree-level upper bound on the mass of this light scalar is given. We
compare this new bound with similar ones existing in the literature and show
how to extract extra information on heavier neutral scalars in the spectrum
from the interplay of independent bounds. Production of these states at future
colliders is addressed and the implications for the decoupling limit in which
only one Higgs is expected to remain light are discussed.


title: Supersymmetric Unification with Radiative Breaking of R-parity

abstract:
  We show how R-parity can break spontaneously as a result of radiative
corrections in unified N=1 supergravity models. We illustrate this with a
concrete rank-four unified model, where the spontaneous breaking of R-parity is
accompanied by the existence of a physical majoron. We determine the resulting
supersymmetric particle mass spectrum and show that R-parity-breaking signals
may be detectable at LEP200.


title: Relativistic effects in radiative transitions of charmonia

abstract:
  In the framework of a relativistic quark model constructed in an infinite
momentum frame, corrections of the order of $v^{2}/c^{2}$ are obtained in the
formulas which express amplitudes of the transitions $\psi(\psi') \to
\eta_{_{c}}(\eta'_{_{c}})\gamma$, $\chi_{_{J}} \to \psi\gamma$, $\psi' \to
\chi_{_{J}}\gamma$, $h_{_{c}} \to \eta_{_{c}}\gamma$, $\eta'_{_{c}} \to
h_{_{c}}\gamma$ through overlap integrals $\int \phi^{*}_{f}(q) \phi_{i}(q)
d{\bf q}$, $\int \phi^{*}_{f}(r)r \phi_{i}(r) d{\bf r}$. These corrections lead
to a considerable suppression of $\Gamma(\psi\to\eta_{_{c}}\gamma)$, however,
they are insufficient to remove the existing disagreement of quark model
predictions with experiment. Taking into account the relativistic corrections,
the ratios of overlap integrals for $\chi_{_{0}} \to \psi\gamma, \chi_{_{2}}
\to \psi\gamma$ and $\psi' \to \chi_{_{0}}\gamma, \psi' \to \chi_{_{2}}\gamma$
transitions are extracted from experiment; the obtained results are compared
with quark model predictions.


title: Preheating and vacuum metastability in Supersymmetry

abstract:
  The constraints imposed by the requirement that the scalar potential of
supersymmetric theories does not have unbounded directions and charge or color
breaking minima deeper than the usual electroweak breaking minimum (EWM) are
significantly relaxed if one just allows for a metastable EWM but with a
sufficiently long lifetime. For this to be acceptable one needs however to
explain how the vacuum state reaches this metastable configuration in the first
place. We discuss the implications for this issue of the inflaton induced
scalar masses, of the supersymmetry breaking effects generated during the
preheating stage as well as of the thermal corrections to the scalar potential
which appear after reheating. We show that their combined effects may
efficiently drive the scalar fields to the origin, allowing them to then evolve
naturally towards the EWM.


title: Renormalization-Scheme Dependence of Pade Summation in QCD

abstract:
  We study the renormalization-scheme (RS) dependence of Pade Approximants
(PA's), and compare them with the Principle of Minimal Sensitivity (PMS) and
the Effective Charge (ECH) approaches. Although the formulae provided by the
PA, PMS and ECH predictions for higher-order terms in a QCD perturbation
expansion differ in general, their predictions can be very close numerically
for a wide range of renormalization schemes. Using the Bjorken sum rule as a
test case, we find that Pade Summation (PS) reduces drastically the RS
dependence of the Bjorken effective charge. We use these results to estimate
the theoretical error due to the choice of RS in the extraction of $\alpha_s$
from the Bjorken sum rule, and use the available data at $Q^2=3 GeV^2$ to
estimate $\alpha_s(M_Z) = 0.117^{+0.004}_{-0.007} \pm 0.002$, where the first
error is experimental, and the second is theoretical.


title: Orbifold-induced $\mu$ term and electroweak symmetry breaking

abstract:
  It is known that a Higgs $\mu$ term can be naturally generated through the
K\"ahler potential in orbifold string models in which one of the three
compactified complex planes has order two. In this class of models explicit
expressions for both the $\mu$ parameter and the soft SUSY-breaking parameters
can be obtained under the assumption that the goldstino is an arbitrary linear
combination of the fermionic partners of the dilaton $S$ and all the moduli
$T_i,U_i$. We apply this picture to the MSSM and explore the consistency of the
obtained boundary conditions with radiative gauge symmetry breaking. We find
that consistency with the measured value of the top-quark mass can only be
achieved if the goldstino has a negligible dilatino component and relevant
components along the $T_3,U_3$ moduli associated to the order-two complex
plane.


title:
Transport Phenomena and Electroweak Baryogenesis in the Two-doublet
  Higgs Model

abstract:
  We use transport equations to compute the evolution of the quark plasma at
the electroweak phase transition in the two-doublet Higgs model, obtaining in a
more rigorous and quantitatively accurate way results consistent with previous
work. We discuss the model in connection with the electroweak baryogenesis
scenario, and claim that the observed baryon asymmetry of the universe can be
obtained within this model with a suitable choice of parameters.


title: Calculation of the $B \to \pi $ Transition Matrix Element in QCD

abstract:
  We describe the calculation of the $B\rightarrow \pi$ hadronic matrix element
from operator product expansion near the light-cone in QCD. In the resulting
sum rules, the form factors $f^+$ and $F_0$ determining this matrix element are
expressed in terms of pion light-cone wave functions. We present predictions
for $f^+$ and $F_0$ in the region of momentum transfer $0 \leq p^2 < m_b^2 -
{\cal O}(\mbox{1 GeV}^2)$ taking into account the wave functions up to twist 4.
We also discuss the extrapolation of the form factors to higher $p^2$ and their
asymptotic dependence on the heavy quark mass.


title: QCD Sum Rule Calculation for the Tensor Charge of the Nucleon

abstract:
  The nucleon's tensor charges (isovector $g^v_T={\delta}u-{\delta}d$ and
isoscalar $g^s_T={\delta}u+{\delta}d$) are calculated using the QCD sum rules
in the presence of an external tensor field. In addition to the standard quark
and gluon condensates, new condensates described by vacuum susceptibilities are
induced by the external field. The latter contributions to $g^v_T$ and $g^s_T$
are estimated to be small. After deriving some simplifying formulas, a detailed
sum rule analysis yields $g^v_T=1.29 \pm 0.51$ and $g^s_T = 1.37 \pm 0.55$, or
${\delta}u=1.33 \pm 0.53$ and ${\delta}d = 0.04 \pm 0.02$ at the scale of 1
GeV$^2$.


title:
VMD description of $\tau \to (\omega,\ \phi) \pi^- \nu_{\tau}$ decays
  and the $\omega-\phi$ mixing angle

abstract:
  Using the vector meson dominance model we get predictions for the
Cabibbo-favored $\tom$ and $\tphi$ decays. We show how the measurements of
these two decays can provide information on the nature of the violation of the
OZI rule.


title:
Determination of the asymptotic behaviour of the heavy flavour
  coefficient functions in deep inelastic scattering

abstract:
  Using renormalization group techniques we have derived analytic formulae for
the next-to-leading order heavy-quark coefficient functions in deep inelastic
lepton hadron scattering. These formulae are only valid in the kinematic regime
Q^2 >> m^2, where Q^2 and m^2 stand for the masses squared of the virtual
photon and heavy quark respectively. Some of the applications of these
asymptotic formulae will be discussed.


title: Quark masses from the linear meson model

abstract:
  Quark mass ratios are expressed within the linear meson model by universal
relations involving only the masses and decay constants of the flavored
pseudoscalars as well as their wave function renormalization. Quantitative
results are in agreement with those obtained from chiral perturbation theory,
with a tendency to a somewhat higher strange quark mass.


title:
Hidden Structure in a Lagrangian for Hyperfine Splitting of the Heavy
  Baryons

abstract:
  We investigate the hyperfine splitting of the heavy baryons in the
bound-state approach. We start with an ordinary relativistic Lagrangian which
has been extensively used to discuss finite mass corrections to the heavy limit
predictions. It turns out that the dominant contribution arises from terms
which do not manifestly break the heavy spin symmetry. The actual heavy spin
violating terms are uncovered by carefully performing a 1/M expansion of this
Lagrangian.


title:
Unitarity Constraints on Anomalous Top Quark Couplings to Weak Gauge
  Bosons

abstract:
  If there is new physics associated with the top quark, it could show up as
anomalous couplings of the top quark to weak gauge bosons, such as $Z\ttbar$
and $W\tbbar$ vector and axial-vector couplings. We use the processes
$\ttbar\to Z^0Z^0$, $\ttbar\to W^+W^-$, and $\ttbar\to Z^0H$ to obtain the
unitarity constraints on these anomalous couplings, and combine these
constraints with those from precision electroweak data. The unitarity
constraints can impose additional limits on the anomalous couplings when the
scale of new physics is as low as 2 TeV. A nonzero measurement of such an
anomalous coupling leads to an upper limit on the new physics scale from the
unitarity condition.


title:
Low energy supersymmetry with a neutralino LSP and the CDF
  ee\gamma\gamma + missing E_T event

abstract:
  We present a refined and expanded analysis of the CDF $ee\gamma\gamma + \Et$
event as superpartner production, assuming the lightest neutralino is the
lightest supersymmetric particle. A general low-energy Lagrangian is
constrained by a minimum cross section times branching ratio into two electrons
and two photons, kinematics consistent with the event, and LEP1-LEP130 data. We
examine how the supersymmetric parameters depend on the kinematics, branching
ratios and experimental predictions with a selectron interpretation of the
event, and discuss to what extent these are modified by other interpretations.
Predictions for imminent CERN LEP upgrades and the present and future Fermilab
Tevatron are presented. Finally, we briefly discuss the possible connection to
other phenomena including a light stop, the neutralino relic density, the shift
in $R_b$ and the associated shift in $\alpha_s$, and implications for the form
of the theory.


title: On Supersymmetric CP Violation

abstract:
  We discuss the discovery potential for New Physics of various measurements of
CP violation. If nature is supersymmetric, then the flavor problem is even more
mysterious than in the standard model. We show how we can learn about the
mechanism that solves the supersymmetric flavor problem from measurements of
mixing and CP violation in $K$, $D$ and $B$ decays. (Invited talk given at the
Workshop on K Physics, Orsay, France, May 30 - June 4, 1996.)


title: $\delta$-Expansion at Finite Temperature

abstract:
  We apply the $\delta$-expansion perturbation scheme to the $\lambda \phi^{4}$
self-interacting scalar field theory in 3+1 D at finite temperature. In the
$\delta$-expansion the interaction term is written as $\lambda (\phi^{2})^{ 1 +
\delta}$ and $\delta$ is considered as the perturbation parameter. We compute
within this perturbative approach the renormalized mass at finite temperature
at a finite order in $\delta$. The results are compared with the usual
loop-expansion at finite temperature.


title: Subcritical Fluctuations at the Electroweak Phase Transition

abstract:
  We study the importance of thermal fluctuations during the electroweak phase
transition. We evaluate in detail the equilibrium number density of large
amplitude subcritical fluctuations and discuss the importance of phase mixing
to the dynamics of the phase transition. Our results show that, for realistic
Higgs masses, the phase transition can be completed by the percolation of the
true vacuum, induced by the presence of subcritical fluctuations.


title: Bounding Heavy Meson Form Factors Using Inclusive Sum Rules

abstract:
  We utilize inclusive sum rules to construct both upper and lower bounds on
the form factors for B to D, D*, rho, pi, omega, K and K* semi-leptonic and
radiative decays. We include the leading nonperturbative 1/E corrections and
point out cases when alpha_s corrections are equally important. We compute the
alpha_s correction to the lower bound on the B to D* form factor f(w) at zero
recoil, thereby constraining its normalization f(1) to within 6-8% of the upper
bound. We show that the B to rho form factor a_+ is suppressed at small
momentum transfer by either a factor of 1/E or alpha_s. These bounds can be
used to rule out phenomenological models as well as to determine values for the
CKM matrix elements once radiative corrections are included.


title: Predictive Models of Large Neutrino Mixing Angles

abstract:
  Several experimental results could be interpreted as evidence that certain
neutrino mixing angles are large, of order unity. However, in the context of
grand unified models the neutrino angles come out characteristically to be
small, like the KM angles. It is shown how to construct simple grand-unified
models in which neutrino angles are not only large but completely predicted
with some precision. Six models are presented for illustration.


title:
Constraining a CP-violating WWV coupling from the W^+W^- threshold cross
  section at LEP2

abstract:
  The most general form of the $WWZ$ and $WW\gamma$ interaction contains a
$CP$-violating term which has the same threshold behaviour as the Standard
Model $\ee \to \ww$ cross section. We calculate the cross section as a function
of the corresponding anomalous coupling, and estimate the bounds which can be
obtained from a measurement of the threshold cross section at LEP2. We show how
the effect of the coupling is most pronounced in the angular distributions of
the final-state fermions.


title:
A Non-Standard String/SUSY Scenario and its Phenomenological
  Implications

abstract:
  We investigate the phenomenology of an orbifold string model in which
supersymmetry breaking is dominated by the overall `size' modulus field and all
matter fields are in the untwisted sector. The possibly close degeneracy of the
lightest neutralino and chargino and the possibly small splitting between the
gluino and chargino/LSP mass imply that discovery of supersymmetry at future
colliders could be more challenging than anticipated. Specialized search
strategies and particular detector features could play an important role. For
preferred model parameter choices, the phenomenology of dark matter in the
universe is significantly modified.


title: Higher Moments of Heavy Quark Vacuum Polarization

abstract:
  We present analytical calculation of the first seven moments of the heavy
quark vacuum polarization function in the three-loop order. The obtained
results are compared against the asymptotic formulas following from the
threshold singularities. We also discuss the $\mu$ dependence of the moments
within the BLM procedure.


title: R-parity breaking and the grand unification program

abstract:
  We present the study of the possibility to have R-parity breaking
interactions in minimal SU(5). An interesting scenario emerges in which the
R-parity breaking coupling $\lambda'_{333}$ is large, and its size is related
to the value of the tau neutrino mass, assuming that supersymmetry is broken
according to low energy supergravity framework. This scenario may also have
implications on the issue of $b-\tau$ unification.


title:
(Anti-)self-dual homogeneous vacuum gluon field as an origin of
  confinement and $SU_L(N_F)\times SU_R(N_F)$ symmetry breaking in QCD

abstract:
  It is shown that an (anti-)self-dual homogeneous vacuum gluon field appears
in a natural way within the problem of calculation of the QCD partition
function in the form of Euclidean functional integral with periodic boundary
conditions. There is no violation of cluster property within this formulation,
nor are parity, color and rotational symmetries broken explicitly. The massless
limit of the product of the quark masses and condensates, $m_f \langle
\bar\psi_f \psi_f \rangle$, is calculated to all loop orders. This quantity
does not vanish and is proportional to the gluon condensate appearing due to
the nonzero strength of the vacuum gluon field. We conclude that the gluon
condensate can be considered as an order parameter both for confinement and
chiral symmetry breaking.


title: On bound states in quantum field theory

abstract:
  The mechanism of formation of bound states in the relativistic quantum field
theory is demonstrated by the Yukawa field model. It is shown that the weak
coupling regime leads to the potential picture, i.e. it is equivalent to the
nonrelativistic limit in the bound state problem. In the strong coupling regime
the potential picture is not valid and the method of bosonisation of fermion
currents (so-called $Z_2=0$ method) should be used. Essentially the nonlocal
fermion currents are found to be responsible for the origin of bound states and
ultraviolet convergence of fermion loops.


title:
The generalized Crewther relation: the peculiar aspects of the
  analytical perturbative QCD calculations

abstract:
  We summarize the current status of our understanding of the structure of the
perturbative QCD expressions for the QCD generalization of the Crewther
relation.


title:
New proton polarized structure functions in charged current processes at
  HERA

abstract:
  Estimates for longitudinal spin asymmetries which single out new polarized
nucleon structure functions in deeply inelastic charged current interactions at
HERA energies are given, exploiting their interpretation in terms of polarized
quark distributions. These asymmetries turn out to be large and allow a
measurement of the new polarized structure functions $g_1^{W}$ and $g_5^{W}$,
which would add valuable tests and information on the spin content of quarks
inside a polarized proton. We also show that single spin asymmetries in neutral
current interactions are very small.


title: Nucleon electroweak form factors: Analysis of their spectral functions

abstract:
  We investigate the imaginary parts of the nucleon electromagnetic and axial
form factors close to threshold in the framework of heavy baryon chiral
perturbation theory. For the isovector electromagnetic form factors, we recover
the well known strong enhancement near threshold. For the isoscalar ones, we
show that there is no visible enhancement due to the three--pion continuum.
This justifies the use of vector meson poles only in dispersion--theoretical
calculations. We also calculate the imaginary part of the nucleon isovector
axial form factor and show that it is small in the threshold region.


title: The $s \to d \gamma$ Transition in Kaon and Hyperon Decays

abstract:
  We survey the possibilities of detecting the $s \rightarrow d \gamma$
transition in kaon and hyperon radiative decays. In the more frequent decays,
like $K^+ \rightarrow \pi^+ \pi^o \gamma$, $K^+ \rightarrow \pi^+ \ell^+
\ell^-$, the short-distance contribution is obscured by various long-distance
transitions. Among the hyperon radiative decays, $\Xi^- \rightarrow \Sigma^-
\gamma$ and $\Omega^- \rightarrow \Xi^- \gamma$ are the leading candidates for
providing a window to the short-distance $s \rightarrow d \gamma$. The
long-distance $s \rightarrow d \gamma$ transitions are also analyzed; their
magnitude depends on the size of the deviation from a sum-rule among couplings
of vector mesons to photons. The measurement of $\Omega^- \rightarrow \Xi^-
\gamma$ could provide information on the relative size of the short and
long-distance contributions to the magnetic component of $s \rightarrow d
\gamma$.


title: Soft Gluon Resummation in Heavy Flavour Production

abstract:
  I discuss the effect of resummation of soft gluons in hadronic production of
high mass systems, and in particular in heavy flavour production. I show that
in widely used $x$-space resummation formulae, spurious terms that grow
factorially in the order of the perturbative expansion are present. These terms
spoil the convergence of the perturbative expansion. I also show that it is
possible to perform the soft gluon resummation in such a way that these terms
are not present. Implications for top and high mass dijet production at the
Tevatron are discussed.


title:
Effective Lagrangian approach to vector mesons, their structure and
  decays$^{*)}$

abstract:
  An improved update of the structure and decays of $\rho^0$, $\omega$ and
$\phi$ mesons based on a chiral SU(3) Lagrangian, including anomaly terms is
presented. We demonstrate that a consistent and quantitatively successful
description of both pion and kaon electromagnetic form factors can be achieved.
We also discuss the $e^+e^- \to \pi^+ \pi^0 \pi^-$ cross section, the Dalitz
decay $\omega \to \pi^0 \mu^+ \mu^-$ and aspects of $\rho^0 \omega$ and $\omega
\phi$ mixing. Relations to previous versions of the Vector Meson Dominance
model will be examined.


title: Chiral expansion of baryon masses and $\sigma$-terms

abstract:
  We analyze the octet baryon masses and the pion/kaon--nucleon $\sigma$--terms
in the framework of heavy baryon chiral perturbation theory. We include {\it
all} terms up-to-and-including quadratic order in the light quark masses,
$m_q$. We develop a consistent scheme to estimate low--energy constants related
to scalar--isoscalar operators in the framework of resonance exchange involving
one--loop graphs. The pertinent low--energy constants can only be estimated up
to some finite coefficients. Including contributions from loop graphs with
intermediate spin--3/2 decuplet and spin--1/2 octet states and from tree graphs
including scalar mesons, we use the octet baryon masses and the pion--nucleon
$\sigma$--term to fix all but one of these coefficients. Physical results are
insensitive to this remaining parameter. It is also demonstrated that two--loop
corrections only modify some of the subleading low--energy constants. We find
for the baryon mass in the chiral limit, $m_0 = 770 \pm 110$ MeV. While the
corrections of order $m_q^2$ are small for the nucleon, they are still sizeable
for the $\Lambda$, the $\Sigma$ and the $\Xi$. Therefore a definitive statement
about the convergence of three--flavor baryon chiral perturbation can not yet
be made. The strangeness content of the nucleon is $y = 0.21 \pm 0.20$. We also
estimate the kaon--nucleon $\sigma$--terms and some two--loops contributions to
the nucleon mass.


title:
Tests of electron flavor conservation with the Sudbury Neutrino
  Observatory

abstract:
  We analyze tests of electron flavor conservation that can be performed at the
Sudbury Neutrino Observatory (SNO). These tests, which utilize $^8$B solar
neutrinos interacting with deuterium, measure: 1) the shape of the recoil
electron spectrum in charged-current (CC) interactions (the CC spectrum shape);
and 2) the ratio of the number of charged current to neutral current (NC)
events (the CC/NC ratio). We determine standard model predictions for the CC
spectral shape and for the CC/NC ratio, together with realistic estimates of
their errors and the correlations between errors. We consider systematic
uncertainties in the standard neutrino spectrum and in the charged-current and
neutral current cross-sections, the SNO energy resolution and absolute energy
scale, and the SNO detection efficiencies. Assuming that either matter-enhanced
or vacuum neutrino oscillations solve the solar neutrino problems, we calculate
the confidence levels with which electron flavor non-conservation can be
detected using either the CC spectrum shape or the CC/NC ratio, or both. If the
SNO detector works as expected, the neutrino oscillation solutions that
best-fit the results of the four operating solar neutrino experiments can be
distinguished unambiguously from the standard predictions of electron flavor
conservation.


title: CPT and Superstring

abstract:
  We discuss the possibility that CPT violation may appear as a consequence of
microscopic decoherence due to quantum-gravity effects, that we describe using
a density-matrix formalism motivated by our studies of non-critical string
theory. The maximum possible order of magnitude of such decohering
CPT-violating effects is not far from the sensitivity of present experiments on
the neutral kaon system, and we review a simple parametrization for them. We
also review a recent data analysis carried out together with the CPLEAR
collaboration, which bounds any such decohering CPT-violating parameters to be
$\lappeq 10^{-19}$ GeV.


title: CPT Violation from Planck Scale Physics

abstract:
  I address the phenomenology of CPT violation in the neutral kaon system under
the assumption that it originates from Planck scale physics. This assumption
opens the door to a new set of CPT violating parameters whose phenomenology is
distinct from the $\Delta$ parameter usually considered in the Hamiltonian. The
origin of these parameters reflects a possible departure from a $S$-matrix
evolution. Existing bounds on CPT violation are near the expected range based
on naive dimensional analysis. This provides a strong incentive to pursue the
quest of CPT violation in near-future kaon experiments. (Talk given at the
Workshop on K Physics, Orsay, France, May 30 - June 4, 1996.)


title: A New Approach to Chiral Perturbation Theory for Matter Fields

abstract:
  I propose a prescription for separating the high- and low-energy
contributions in effective field theories. This prescription allows a
relativistic treatment of matter fields in chiral perturbation theory while the
power counting remains valid.


title: CP and T violation test in neutrino oscillation

abstract:
  We examine how large violation of CP and T is allowed in long base line
neutrino experiments. When we attribute only the atmospheric neutrino anomaly
to neutrino oscillation we may have large CP violation effect. When we
attribute both the atmospheric neutrino anomaly and the solar neutrino deficit
to neutrino oscillation we may have a sizable T violation effect proportional
to the ratio of two mass differences; it is difficult to see CP violation since
we can't ignore the matter effect. We give a simple expression for T violation
in the presence of matter.


title:
Analyzing the nucleon spin in weak interaction processes at HERA
  energies

abstract:
  We investigate the possibility to measure the spin content carried by the
different quark flavors in a nucleon by means of polarized deep inelastic
scattering with $W^\pm$ exchange at HERA. Such measurements require a polarized
proton beam. The expected inclusive and semi inclusive asymmetries are sizable
and for realistic luminosities the expected statistical accuracies are good
enough to extract new and relevant information on the valence quark and the
strange sea distributions.


title: SU(3)_LxU(1)_N Model for Right-Handed Neutrino Neutral Currents

abstract:
  A model based on the $\mbox{SU(3)}_L\otimes \mbox{U(1)}_N$ gauge group, in
which neutrinos have right-handed neutral currents is considered. We argue that
in order to have a result consistent with low-energy one, the right-handed
neutrino component must be treated as correction instead of an equivalent spin
state.


title:
Fully quantum treatment of the Landau--Pomeranchuk--Migdal effect in QED
  and QCD

abstract:
  For the first time a rigorous quantum treatment of the
Landau-Pomeranchuk-Migdal effect in QED and QCD is given. The rate of photon
(gluon) radiation by an electron (quark) in medium is expressed through the
Green's function of a two-dimensional Schr\"odinger equation with an imaginary
potential. In QED this potential is proportional to the dipole cross section
for scattering of $e^{+}e^{-}$ pair off an atom, in QCD it is proportional to
the cross section of interaction with color centre of the color singlet
quark-antiquark-gluon system.


title: Deep Inelastic Scattering -- Theory and Phenomenology

abstract:
  Recent developments in theory and phenomenology relevant to deep inelastic
lepton scattering are reviewed, concentrating on the following topics:
Predicted behaviour of non-singlet and polarized structure functions at small
$x$; Theoretical studies of saturation and unitarity effects at small $x$ in
quarkonium scattering; Renormalons and higher twist contributions;
Next-to-leading-order calculations of jet cross sections; Forward jet
production as a probe of small-$x$ dynamics.


title: Inclusive Prompt Photon Production in Polarized pp Collisions at HERA-N

abstract:
  We present a NLO study of inclusive polarized prompt photon production in a
conceivable fixed target $pp$ mode of HERA with longitudinally polarized
protons at $\sqrt{s}=39$ GeV. We analyze the sensitivity of the corresponding
double spin asymmetry to the proton's polarized gluon distribution $\Delta g$
and estimate the expected statistical precision in its determination. The main
theoretical uncertainties in the predictions are examined.


title: Semileptonic Decays of Heavy Flavors in QCD

abstract:
  A model independent approach based on a generalization of the operator
product expansion is used to describe semileptonic decays of heavy flavors. In
the first part of the dissertation we calculate differential distributions in
the inclusive semileptonic weak decays of heavy flavors in QCD. In particular,
the double distribution in electron energy and invariant mass of the lepton
pair is calculated. The distributions are calculated as series in $m_Q^{-1}$
where $m_Q$ is the heavy quark mass. All effects up to $m_Q^{-2}$ are included.
  Also calculated are the energy distribution and semileptonic decay width for
the case of a heavy lepton in the final state.
  Based on the results of the first part of the work, we calculate the full up
to order $1/m_Q^2$ set of the OPE sum rules for the heavy flavor transitions
and radiative corrections to them up to order $\alpha_s\Lambda_{QCD}/m_Q$.
  In the second part of this work a new model is proposed for the inclusive
semileptonic decays of the $B$ mesons $B\rightarrow l\bar{\nu}X_c$, which is
{\em defined} by the requirement that it should satisfy the QCD consistency
conditions. These conditions are imposed in the form of the OPE sum rules. It
is shown that under some natural assumptions the OPE sum rules provide
sufficient number of constraints to fully determine exclusive contributions of
a number of resonances in the final state of the decay. The theoretical results
for the model are presented in the form suitable for comparison with
experimental data. The proposed model can be used for experimental measurements
of the heavy meson matrix element $\mu _\pi ^2$ which describes the kinetic
energy of the heavy quark inside the hadron, as well as for extraction of the
value of $|V_{cb}|$ from experimental data and other applications.


title: Prospects for measurements of CP violation at hadron colliders

abstract:
  A brief review of the strategies used in looking for CP violation in B decays
is presented. Some problems due to penguin diagrams are addressed. Penguin
trapping is discussed, in the context of the upcoming experiments. The high
rates and the possibility to perform experiments on the $B_s$ system justify
the interest in hadronic colliders.


title: Form Factors of Kaon Semileptonic Decays

abstract:
  A calculation of the semi--leptonic decays of the kaon ($K_{l3}$) is
presented. The results are direct predictions of a covariant model of the pion
and kaon introduced earlier by Ito, Buck, Gross. The weak form factors for
$K_{l3}$ are predicted with absolutely no parameter adjustments of the model.
We obtained for the form factor parameters:
$f_-(q^2=m_l^2)/f_+(q^2=m_l^2)=-0.28$ and $\lambda_+$= 0.028, both within
experimental error bars. Connections of this approach to heavy quark symmetry
will also be discussed.


title:
The Essential Role of String-Derived Symmetries in Ensuring
  Proton-Stability and Light Neutrino Masses

abstract:
  The paper addresses the problem of suppressing naturally the unsafe d=4 as
well as the color-triplet mediated and/or gravity-linked d=5 proton-decay
operators, which generically arise in SUSY-unification. It also attempts to
give light masses to the neutrinos, of the type suggested by current
experiments. It is noted that neither the symmetries in $SO(10)$, nor those in
$E_6$, suffice for the purpose -- especially in the matter of suppressing
naturally the d=5 proton-decay operators. By contrast, it is shown that a
certain {\it string-derived symmetry}, which cannot arise within conventional
grand unification, but which does arise within a class of three-generation
string-solutions, suffices, in conjuction with $B-L$, to safeguard
proton-stability from all potential dangers, including those which may arise
through higher dimensional operators and the color-triplets in the infinite
tower of states. At the same time, the symmetry in question permits neutrinos
to acquire appropriate masses. This shows that {\it string theory plays an
essential role in ensuring natural consistency of SUSY-unification with two
low-energy observations -- proton-stability and light masses for the
neutrinos}. The correlation between the masses of the extra $Z'$-boson (or
bosons), which arise in these models, and proton-decay rate is noted.