title: Nucleon Decay in GUT and Non-GUT SUSY Models

abstract:
  I first emphasize the importance of searching for nucleon decay in the
context of supersymmetric models. The status of minimal SUSY SU(5) model is
reviewed, which can be definitively ruled out by a combination of
superKamiokande and LEP-2 experiments. Non-minimal models may provide some
suppression in the nucleon decay rates, but there is still a good chance for
superKamiokande. I point out that the operators suppressed even by the
Planck-scale are too large. We need a suppression mechanism for the operators
at the level of $10^{-7}$, and the mechanism, I argue, may well be a flavor
symmetry. A particular example predicts $p \rightarrow K^0 e^+$ to be the
dominant mode which does not arise in GUT models.


title:
Determining the existence and nature of the quark-gluon plasma by
  Upsilon suppression at the LHC

abstract:
  Minijet production in $\sqrt{s} = 5.5$ TeV Pb+Pb collisions at the LHC is
expected to produce a gluon-dominated plasma with large initial temperatures
and energy densities. We discuss the implications of the high initial
temperatures on the screening mass and on the relative suppression of members
of the $\Upsilon$ family. We demonstrate that $p_T$-dependence of the
$\Upsilon'/\Upsilon$ ratio is only expected if a quark-gluon plasma with
significant energy density is present, and that the precise dependence of this
ratio will strongly constrain the QGP models. We also propose that the $p_T$
spectra of the $\Upsilon$ resonances themselves will provide valuable
information by comparing these spectra to that of the $Z$ boson, which should
not be influenced by plasma production.


title:
Using Higgs Pair Production in $e^+e^-$ or $\mu^+\mu^-$ Collisions To
  Probe GUT-Scale Boundary Conditions in the Minimal Supersymmetric Model

abstract:
  We delineate the techniques and prospects for using Higgs pair production in
$e^+e^-$ or $\mu^+\mu^-$ collisions to probe GUT-scale boundary conditions in
the minimal supersymmetric standard model.


title: $Q^2$ dependence of chiral-odd twist-3 distribution $e(x,Q^2)$

abstract:
  We discuss the $Q^2$ dependence of the chiral-odd twist-3 distribution
$e(x,Q^2)$. The anomalous dimension matrix for the corresponding twist-3
operators is calculated in the one-loop level. This study completes the
calculation of the anomalous dimension matrices for all the twist-3
distributions together with the known results for the other twist-3
distributions $g_2(x,Q^2)$ and $h_L(x,Q^2)$. We also have confirmed that in the
large $N_c$ limit the $Q^2$-evolution of $e(x,Q^2)$ is wholely governed by the
lowest eigenvalue of the anomalous dimension matrix which takes a very simple
analytic form as in the case of $g_2$ and $h_L$.


title: Nuclear beams in HERA

abstract:
  A study has been made of the physics interest and feasibility of experiments
with nuclear beams in HERA. It is shown that such experiments widen
considerably the horizon for probing QCD compared to that from free nucleon
targets. In addition there is some sensitivity to physics beyond the standard
model. Hence the option to include circulating nuclear beams in HERA allows a
wide range of physics processes to be studied and understood.


title:
Higgs and Top Production in the Reaction $\gamma e \to \nu b \bar{b} W$
  at TeV Linear Collider Energies

abstract:
  For an electron-photon collider the complete tree-level cross sections of the
reaction $\gamma e \rightarrow \nu b \bar{b} W$ are computed at center-of-mass
energies between 0.5 and 2.0 TeV, for top masses of 160 to 200 GeV and Higgs
masses between 80 and 140 GeV within the Standard Model. It is shown that most
of the $\nu b \bar{b}$ events are due to Higgs and $Z/\gamma^*$ production
(with $H, Z/\gamma^* \rightarrow b \bar{b}$ decay) while top production (with
$t \rightarrow bW$ decay) is about 50% smaller. Multiperipheral background and
interferences are small, respectively negligible, in the energy range studied.
By convoluting the basic cross sections with an energy spectrum of the
backscattered photon beam, and inserting linear collider luminosities as
anticipated in present designs, realistic $\nu b \bar{b} W$ event rates are
estimated. This results in large event rates for $\gamma e \rightarrow \nu t b$
and $\gamma e \rightarrow \nu H W$. We estimate that the CKM matrix element
$|V_{tb}|$, can be probed from the $\nu t b$ final state to an accuracy of 1-3%
at $\sqrt{s_{e^+e^-}} > 1 TeV$. Assuming an effective Lagrangian based on
dimension-6 operators we discuss the sensitivity for detecting deviations of
the HWW coupling from the Standard Model in the reaction $\gamma e \rightarrow
\nu H W$.


title: BLM-Resummation and OPE in Heavy Flavor Transitions

abstract:
  An all-order resummation is performed for the effect of the running of the
strong coupling in the zero recoil sum rule for the axial current and for the
kinetic operator \vec\pi^2. The perturbative corrections to well-defined
objects of OPE turn out to be very moderate. The renormalization of the kinetic
operator is addressed.


title: The current picture of Glueballs

abstract:
  Some recent developments in the phenomenology of the lightest scalar glueball
are summarised. Tools for determining the gluonic content of a resonance of
known mass, width and $J^{PC}$ from its branching fraction in radiative
quarkonium decays and production cross section in $\gamma \gamma$ collisions
are presented. Two $q\bar{q} - G$ mixing schemes for $J^{PC} = 0^{++}$,
inspired by the lattice, are shown to lead to similar phenomenology that may be
tested at BEPC and in $\gamma \gamma$ production at LEP2.


title: The Small-x Evolution of Unpolarized and Polarized Structure Functions

abstract:
  A brief overview is presented of recent developments concerning resummed
small-x evolution, based upon the renormalization group equation. The
non-singlet and singlet structure functions are discussed for both polarized
and unpolarized deep-inelastic scattering. Quantitative results are displayed
and uncertainties from uncalculated subleading terms are discussed.


title: RPA-Approach to the Excitations of the Nucleon, Part II: Phenomenology

abstract:
  The tensor-RPA approach developed previously in part I is applied to the
Nambu-Jona-Lasinio (NJL) model. As a first step we investigate the structure of
Dirac-Hartree-Fock solutions for a rotationally and isospin invariant
ground-state density. Whereas vacuum properties can be reproduced, no solitonic
configuration for a system with unit baryon number is found. We then solve the
tensor-RPA equation employing simple models of the nucleon ground state. In
general the ph interaction effects a decrease of the excited states to lower
energies. Due to an enhanced level density at low energies the obtained spectra
cannot be matched with the experimental data when a standard MIT-bag
configuration is used. However, when the size of the nucleon quark core is
reduced to approximately 0.3 fm a fair description of the baryon spectrum in
the positive-parity channel is achieved. For this purpose the residual
interaction turns out to be crucial and leads to a significant improvement
compared with the mean-field spectra.


title: CNI Polarimetry and the Hadronic Spin Dependence of pp Scattering

abstract:
  Methods for limiting the size of hadronic spin-flip in the Coulomb-Nuclear
Interference region are critically assessed. This work was presented at the
High Energy Polarimetry Workshop in Amsterdam, Sept.9, 1996 and the RHIC Spin
Collaboration meeting in Marseille, Sept. 17, 1996.


title: Azimuthal angles in diffractive ep collisions

abstract:
  We investigate azimuthal correlations in deep inelastic diffractive
scattering, e + p -> e + \tilde{p} + X. The dependence of the ep cross section
on the angle between the lepton plane and some direction in the hadronic final
state can be written in a simple form; its measurement can be used to constrain
the cross section for longitudinally polarised photons. Using the model of
nonperturbative two-gluon exchange of Landshoff and Nachtmann we calculate the
distribution of the azimuthal jet angle in diffractive dijet production and
find that useful bounds on the longitudinal cross section for such events might
be obtained from its measurement. We then discuss the predictions of this model
for the dependence of the ep cross section on the azimuthal angle of the proton
remnant \tilde{p}, which contains information about the helicity content of the
pomeron.


title:
The Role of the Anomalous U(1)_A for the Solution of the Doublet-Triplet
  Splitting Problem

abstract:
  The anomalous U(1)_A symmetry provides a generic method of getting accidental
symmetries. Therefore, it can play a crucial role in solving the
doublet-triplet splitting and the \mu-problems via the `pseudo-Goldstone'
mechanism: U(1)_A can naturally uncorrelate the two grand unified Higgs sectors
in the superpotential and simultaneously induce the desired expectation values
through the Fayet-Iliopoulos D-term. The zero modes of the resulting compact
vacuum degeneracy can be identified with the massless electroweak Higgs
doublets. This automatically solves the doublet-triplet splitting and the
\mu-problems to all orders in M_P^{-1}. No additional discrete or global
symmetries are needed. U(1)_A can also play the role of the `matter parity' and
suppress the baryon number violating operators. We present the simplest SU(6)
gauge model with a minimal Higgs sector and no doublet-triplet splitting
problem. This model also relates the fermion mass hierarchy to the hierarchy of
scales and predicts, for the generic non-minimal Kahler potential,
approximately universal values for the tree-level electroweak Higgs mass
parameters.


title: Transverse Momentum of Psi and Dimuon Production in Pb+Pb Collisions

abstract:
  CERN collaboration NA50 has measured charmonium and Drell-Yan dimuon
production in Pb+Pb collisions. Parton scattering broadens the transverse
momentum, p_T, distributions for these processes. We predict that the average
p_T^{2} will flatten in Pb+Pb collisions as a function of the neutral
transverse energy of hadrons, E_T, in contrast to the almost-linear rise seen
in S+U - psi +X. If seen, such a flattening will support hadronic explanations
of charmonium suppression. Figures 2 and 5 are improved and numerous
typographical errors are corrected.


title: Next-to-Leading Order Gluonic Three Jet Production at Hadron Colliders

abstract:
  We report the results of a next-to-leading order event generator of purely
gluonic jet production. This calculation is the first step in the construction
of a full next-to-leading order calculation of three jet production at hadron
colliders. Several jet-algorithms commonly used in experiments are implemented
and their numerical stability is investigated.


title: Jets and Partons

abstract:
  Jet production in high energy hadron-hadron collisions can serve as a probe
for new physics. I review recent data from CDF and D0 on the high E_T jet cross
section. Reporting on recent work of the CTEQ collaboration, I argue that the
apparent excess seen in the CDF data may be due to the gluon distribution
function used in the theoretical calculation being too small at large x. I
discuss data on the dijet angular distribution, which shows no sign of a new
physics signal.


title: Consistency test of the Standard Model

abstract:
  If the "Higgs mass" is not the physical mass of a real particle but rather an
effective ultraviolet cutoff then a process energy dependence of this cutoff
must be admitted. Precision data from at least two energy scale experimental
points are necessary to test this hypothesis. The first set of precision data
is provided by the $Z$-boson peak experiments. We argue that the second set can
be given by 10-20GeV $e^+e^-$ colliders. We put attention to the special role
of tau polarization experiments that can be sensitive to the "Higgs mass" for a
sample of $\sim10^8$ produced tau pairs. We argue that such a study may be
regarded as a negative selfconsistency test of the Standard Model and of most
of its extensions.


title: Asymmetry Effects in Polarized Hadron Scattering

abstract:
  We calculate the single-spin and double-spin asymmetry differential cross
sections for the polarized hadron scattering $PP \to l^+ l^- + jet$ up to
$O(\alpha_s)$ by the helicity amplitude method. Numerical results of the
differential cross sections, which can be used to probe the spin contents of
the proton, are obtained with several sets of polarized parton distribution
functions.


title: Predictions for Anomalous tau+ tau- gamma Production at LEP 1

abstract:
  We calculate distributions for tau+ tau- gamma production at LEP 1 taking
into account a potentially existing anomalous magnetic moment a_tau of the tau
lepton. The existing upper limits for |a_tau| are known from the dependence of
the decay Z -> tau+ tau- gamma on (a_tau)^2 and are of the order of (1 - 5)%.
We show that such limits are also sensitive to linear terms in a_tau, which are
of equal importance at |a_tau| ~ (1 - 2)% and dominate below this value.
Contributions from an electric dipole moment d_tau do not interfere with the
electromagnetic vertex or with the anomalous magnetic moment. Appropriate
formulae are derived.


title: Equal-Time Hierarchies for Quantum Transport Theory

abstract:
  We investigate in the equal-time formalism the derivation and truncation of
infinite hierarchies of equations of motion for the energy moments of the
covariant Wigner function. From these hierarchies we then extract kinetic
equations for the physical distribution functions which are related to
low-order energy moments, and show how to determine the higher order moments in
terms of these lowest order ones. We apply the general formalism to scalar and
spinor QED with classical background fields and compare with the results
derived from the three-dimensional Wigner transformation method.


title: Radiative neutrino decays in very strong magnetic fields

abstract:
  The radiative decay $\nu_H \to \nu_L + \gamma$ of massive neutrinos is
analyzed in the framework of the standard model with lepton mixing for very
strong magnetic fields $B\gg B_{cr} = m_e^2/e \sim 4.14 \times 10^{13}$G. The
analysis is based on the approximate decay amplitude obtained by Gvozdev et al.
Numerical results as well as analytical approximations for the decay rate are
obtained for energies of the initial neutrino below and {\em above} the
electron-positron pair creation threshold $2m_e$.


title: Breaking Flavour Symmetry Spontaneously

abstract:
  A new mechanism for spontaneous breaking of flavour symmetry is demonstrated.
An exactly flavour symmetric model with degenerate bare nonets and with
sufficiently strong tri-linear meson couplings is shown to lead to
self-consistency equations which are unstable. Instead there exists a stable
solution, which break flavour symmetry spontaneously in the mass spectrum. For
a C-degenerate meson spectrum the stable mass spectrum obeys the
Okubo-Zweig-Iizuka (OZI) rule and the approximate equal spacing rule.


title: SUSY SU(6) GUT without Gauge Hierarchy Problem

abstract:
  A solution of the doublet-triplet splitting problem in the supersymmetric
$SU(6)$ gauge theory is suggested. The `missing doublet' multiplet -- 175-plet
of the $SU(6)$ group as well as the custodial $SU(2)_{cus}$ global symmetry
play crucial role for achieving the doublet-triplet hierarchy. Two examples in
which the doublet-triplet splitting occurs naturally are presented.


title:
Rapidity gaps and production of minijets in high-energy hadronic
  collisions

abstract:
  High energy hadronic interactions can produce a final state characterized by
minijets separated by a large gap in the rapidity distribution of the produced
secondary particles. We discuss the process by keeping into account the
possibility of having multiple parton collisions in the hadronic interaction.
At Tevatron energy the correction to the single scattering term induced by the
presence of multiparton interactions is large for transverse momenta smaller
than 6 GeV.


title:
One More Analytic Result for $\alpha^{2}(Z\alpha)^{5}m$ Correction to
  the Lamb Shift

abstract:
  The analytic result for the radiative correction of order
$\alpha^{2}(Z\alpha)^{5}m$ to the Lamb shift connected with a polarization
insertion in one of the two external Coulomb lines is obtained. This correction
arises from a gauge invariant set of diagrams which contain, besides the
polarization insertion in the Coulomb leg, all one-loop radiative photon
insertions in the electron line with two external Coulomb lines.


title: Axial-vector currents and tau mesonic decays

abstract:
  A general expression of the axial-vector current is presented, in which both
the effects of the chiral symmetry breaking and the spontaneous chiral symmetry
breaking are included. A new resonance formula of the axial-vector meson is
derived and in the limit of $q^{2}\rightarrow 0$ this formula doesn't go back
to the ``chiral limit``. The studies show that the dominance of the
axial-vector meson is associated with the satisfaction of PCAC. The dominance
of pion exchange is companied by the strong anomaly of PCAC.


title: Strange Hadronic Loops of the Proton: A Quark Model Calculation

abstract:
  Nontrivial $q \bar q$ sea effects have their origin in the low-$Q^2$ dynamics
of strong QCD. We present here a quark model calculation of the contribution of
$s \bar s$ pairs arising from a {\it complete} set of OZI-allowed strong
$Y^*K^*$ hadronic loops to the net spin of the proton, to its charge radius,
and to its magnetic moment. The calculation is performed in an ``unquenched
quark model" which has been shown to preserve the spectroscopic successes of
the naive quark model and to respect the OZI rule. We speculate that an
extension of the calculation to the nonstrange sea will show that most of the
``missing spin" of the proton is in orbital angular momenta.


title: Top Decay in Topcolor-Assisted Technicolor

abstract:
  Conventional technicolor models with light charged technipions ($\pi ^{\pm}
_T$) lead to an unacceptably large contribution to $t\ra {\pi ^+_T} b$ decay
rate. Topcolor-assisted technicolor models also have additional PGBs called
top-pions ($\pi ^{\pm}_t$) which may contribute to this decay. We study the
potentially dangerous mixing of charged top-pion and technipions in toy models
of `natural' topcolor-assisted technicolor. We find that the $t\ra {\pi
^+_{t,T}} b$ decay rate in such models can be within experimental limits due to
a combination of heavy top-pion and small $\pi _t - \pi_T$ mixing.


title:
$\eps$ expansion analysis of very weak first-order transitions in the
  cubic anisotropy model: Part I

abstract:
  The cubic anisotropy model provides a simple example of a system with an
arbitrarily weak first-order phase transition. We present an analysis of this
model using $\eps$-expansion techniques with results up to
next-to-next-to-leading order in $\eps$. Specifically, we compute the relative
discontinuity of various physical quantities across the transition in the limit
that the transition becomes arbitrarily weakly first-order. This provides a
useful test-bed for the application of the $\eps$ expansion in weakly
first-order transitions.


title:
$\epsilon$ expansion analysis of very weak first-order transitions in
  the cubic anisotropy model, Part II

abstract:
  A companion article analyzed very weakly first-order phase transitions in the
cubic anisotropy model using $\eps$ expansion techniques. We extend that
analysis to a calculation of the relative discontinuity of specific heat across
the transition.


title: Unified Theories with U(2) Flavor Symmetry

abstract:
  A general operator expansion is presented for quark and lepton mass matrices
in unified theories based on a U(2) flavor symmetry, with breaking parameter of
order $V_{cb} \approx m_s/m_b \approx \sqrt{m_c/m_t}$. While solving the
supersymmetric flavor-changing problem, a general form for the Yukawa couplings
follows, leading to 9 relations among the fermion masses and mixings, 5 of
which are precise. The combination of grand unified and U(2) symmetries
provides a symmetry understanding for the anomalously small values of $m_u/m_c$
and $m_c/m_t$. A fit to the fermion mass data leads to a prediction for the
angles of the CKM unitarity triangle, which will allow a significant test of
these unified U(2) theories. A particular SO(10) model provides a simple
realization of the general operator expansion. The lighter generation masses
and the non-trivial structure of the CKM matrix are generated from the exchange
of a single U(2) doublet of heavy vector generations. This model suggests that
CP is spontaneously broken at the unification scale --- in which case there is
a further reduction in the number of free parameters.


title:
Azimuthal Dependence of Forward-Jet Production in DIS in the High-Energy
  Limit

abstract:
  As a signal for the BFKL Pomeron in small-x deep inelastic $ep$ scattering,
we calculate the azimuthal dependence of the inclusive cross section of forward
jets relative to the outgoing electron. For not very large differences in
rapidity between the current jet and the forward jet the cross section peaks at
$\pi/2$. For increasing rapidity BFKL dynamics predicts a decorrelation in the
azimuthal dependence between the electron and the forward jet.


title: Instantons in QCD

abstract:
  We review the theory and phenomenology of instantons in QCD. After a general
overview, we provide a pedagogical introduction to semi-classical methods in
quantum mechanics and field theory. The main part of the review summarizes our
understanding of the instanton liquid in QCD and the role of instantons in
generating the spectrum of light hadrons. We also discuss properties of
instantons at finite temperature and the chiral phase transition. We give an
overview over the importance of instantons in some other models, in particular
two dimensional sigma models, electroweak theory and supersymmetric QCD.


title: Spin Physics with Top Quarks at Hadron Colliders

abstract:
  We discuss the prospects to observe effects of transverse polarization and
spin-spin correlations of top quark pairs produced at hadron colliders.


title:
Nonet Classification of Scalar/Isoscalar Resonances in the Mass Region
  below 1900 MeV: Observation of the Lightest Scalar Glueball

abstract:
  We summarize the results of the investigation of the $IJ^{PC}=00^{++}$ wave
which is devoted to the search for the lightest scalar glueball. In the
framework of the K-matrix formalism, the $q\bar q$-nonet classification of the
scalar/isoscalar states is performed in the mass region below 1900 MeV basing
on the following data: GAMS data for $\pi^-p\to\pi^0\pi^0n$, $\eta\eta n$,
$\eta\eta'n$; CERN-M\"unich data for $\pi^-p\to\pi^+\pi^-n$; Crystal Barrel
data for $p\bar p\to\pi^0\pi^0\pi^0$, $\pi^0\pi^0\eta$, $\pi^0\eta\eta$; BNL
data for $\pi\pi\to K\overline K$. It is shown the existence of an extra state
for $q\bar q$ classification: this state is a good candidate for the lightest
scalar glueball. Analysis of the glueball/$q\bar q$ mixing shows that the
glueball state has mainly dispersed over three real resonances: $f_0(1300)$,
$f_0(1500)$ and $f_0(1530^{+90}_{-250})$. The broad resonance with complex mass
$m=1530^{+90}_{-250}-i(560\pm 140)$ MeV is descendant of the pure glueball. The
restored mass of the pure glueball is equal to 1695 MeV. This value agrees well
with the results of lattice gluodynamics.


title: QCD Pomeron as a soliton wave

abstract:
  I review a recent progress in understanding of QCD Pomeron and its relation
to exactly solvable models.


title: Theoretical Review of B-physics

abstract:
  Weak decays and mixing of B-hadrons play a special role in our understanding
of the physics of the Standard Model and beyond. The measured amplitudes,
however, result from a complicated interplay of weak and strong interaction
effects. Understanding strong interaction dynamics, which becomes simpler for
heavy quarks, is thus a fundamental part of the game. In this review, several
theoretical aspects of B dynamics which are relevant for current and future
experimental measurements are discussed.


title:
Virtual Top-Quark Effects on the H->bb-bar Decay at Next-to-Leading
  Order in QCD

abstract:
  By means of a heavy-top-quark effective Lagrangian, we calculate the
three-loop corrections of O(alpha_s^2 G_F M_t^2) to the H->bb-bar partial decay
width of the standard-model Higgs boson with intermediate mass M_H<<2M_t. We
take advantage of a soft-Higgs theorem to construct the relevant coefficient
functions. We present our result both in the MS-bar and on-shell schemes of
mass renormalization. The MS-bar formulation turns out to be favourable with
regard to the convergence behaviour. We also test a recent idea concerning the
naive non-abelianization of QCD.


title: Review of Electroweak Theory

abstract:
  This talk summarizes the status of the standard model predictions for
electroweak precision observables including g-2 for muons, and discusses the
status of the standard model and the MSSM in view of the new data.


title: Astrophysical bounds on superlight gravitinos

abstract:
  We derive the allowed mass range for the superlight gravitino present in a
large class of supersymmetric models from the observed luminosity from
Supernova 1987A. We find that for photino masses of order 100 GeV, the mass
range $2.6\times 10^{-6} eV \leq m_{\tilde{g}} \leq 2.2\times 10^{-8} eV$ for
the gravitino $\tilde{g}$ is excluded by SN1987A observations. Unlike the
bounds on $m_{\tilde{g}}$ from nucleosynthesis, the bounds in the present paper
do not depend critically on the uncertainties of the observational input.


title: The role of massive states in chiral perturbation theory

abstract:
  I review some basic facts about the chiral limit of QCD. This allows to
formulate an effective field theory below the chiral symmetry breaking scale,
chiral perturbation theory (CHPT). I show that for threshold reactions, the
spectrum of QCD is most economically encoded in a set of coupling constants of
operators of higher chiral dimension. A consistent scheme to incorporate the
$\Delta(1232)$ is also discussed and some examples are given. It is stressed
that more precise low--energy data are needed to further test and sharpen the
resonance saturation hypothesis in the presence of baryons.


title: Supersymmetric Dark Matter

abstract:
  A review of recent developments in the analyses of supersymmetric dark matter
is given.


title: Flavour Changing Neutral Current Processes

abstract:
  We review the status of the flavour-changing neutral-current processes
(FCNC). In particular we discuss: i) Main targets of the field, ii) The
theoretical framework for FCNC, iii) Standard analysis of the unitarity
triangle, iv) $\varepsilon'/\varepsilon$, v) Radiative, rare and CP-violating
decays, vi) CP-asymmetries in B-decays, vii) Comparision of the potentials of
$K \to \pi\nu\bar\nu$ and CP-B asymmetries, vii) Some aspects of the physics
beyond the Standard Model.


title: Hard Scattering in QCD

abstract:
  Recent developments in the theory and experiment of QCD hard scattering are
described.


title: Non-Supersymmetric Extensions of the Standard Model

abstract:
  The motivations for studying dynamical scenarios of electroweak and flavor
symmetry breaking are reviewed and the latest ideas, especially
topcolor-assisted technicolor, are summarized. Several technicolor signatures
at the Tevatron and Large Hadron Collider are described and it is emphasized
that all of them are well within the reach of these colliders. (This is the
written version of a plenary talk of this title at the 28th International
Conference on High Energy Physics, Warsaw (1996).)


title: Production of Two Non-Conjugate Leptoquarks in $e^-e^-$ Collisions

abstract:
  We study the production of scalar and vector leptoquarks in $e^-e^-$
scattering. We use the most general couplings to the known fermions which are
dimensionless, baryon and lepton number conserving, and $SU(3)_c \otimes
SU(2)_L \otimes U(1)_Y$ invariant. Expressions are presented for production
cross sections and predictions are given for future linear colliders.


title: A Study of the Behavior of Ultra-High Energy Neutrinos

abstract:
  Neutrino Oscillations in the presence of strong gravitational fields are
studied specifically for Majorana neutrinos. We look at ultra high energy
neutrinos $(\sim 1$ PeV) emanating from Active Galactic Nuclei (AGN). Fluxes of
different flavor neutrinos are estimated and probabilities for different
neutrino transitions calculated.


title:
The $\Delta B = - \Delta Q$ transitions and $B_d \leftrightarrow \bar
  B_d$ oscillations

abstract:
  We estimate the product of the relative strength of the $\Delta B = -\Delta
Q$ amplitude in the decay $B_d^0 \rightarrow D^{*} \ell \bar \nu_{\ell }$ and
the width-difference parameter $y$. For this we have used the data on
time-dependence of $B_{d}^0\bar B_{d}^0$ oscillations in Z decays and the
fraction of like-sign dilepton events at the $\Upsilon (4S)$.


title: Towards Automatic Analytic Evaluation of Massive Feynman Diagrams

abstract:
  A method to calculate two-loop self-energy diagrams of the Standard Model is
demonstrated. A direct physical application is the calculation of the two-loop
electroweak contribution to the anomalous magnetic moment of the muon
${1/2}(g-2)_{\mu}$. Presently we confine ourselves to a ``toy'' model with only
$\mu$, $\gamma$ and a scalar particle (Higgs). The algorithm is implemented as
a package of computer programs in FORM. For generating and automatically
evaluating any number of two-loop self-energy diagrams, a special C-program has
been written. This program creates the initial FORM-expression for every
diagram generated by QGRAF, executes the corresponding subroutines and sums up
the final results.


title: Bounds on Long-Lived Relics from Diffuse Gamma Ray Observations

abstract:
  We place bounds on long-lived primordial relics using measurements of the
diffuse gamma ray spectrum from EGRET and COMPTEL. Bounds are derived for both
radiative and hadronic decays with stronger bounds applying for the latter
decay mode. We present an exclusion plot in the relic density-lifetime plane
that shows nontrivial dependence on the mass of the relic. The violations of
scaling with mass are a consequence of the different possible scattering
processes which lead to differing electromagnetic showering profiles. The
tightest bounds for shorter lifetimes come from COMPTEL observations of the low
energy part of the spectrum, while for longer lifetimes the highest observable
energy at EGRET gives the tightest bounds. We discuss the implications of the
bounds for dark matter candidates as well as relics that have a mass density
substantially below the critical density. These bounds can be utilized to
eliminate models that contain relics with lifetimes longer than $10^{-4}$ times
the age of the universe.


title: The fate of the leptophobic Z'

abstract:
  We review the main features of the leptophobic-Z' phenomenology, commenting
on the prospects of these models after the recent experimental results on R_c,
R_b and after the recent theoretical analyses of jet production at the
Tevatron.


title:
Analysis of LEP Constraints on Supersymmetric Models with a Light
  Gravitino

abstract:
  We propose an analysis of LEP constraints on radiative neutralino decays into
a light gravitino, based on the plane of the Higgs mixing parameter mu and the
SU(2) gaugino mass M_2. The preliminary LEP 2W constraints in the (mu, M_2)
plane are considerably stronger than for supersymmetric models in which the
lightest neutralino is stable. A significant portion of the parameter space in
which chargino or selectron decay into a final state containing a light
gravitino could provide an interpretation of the CDF ee gamma gamma + E_T,miss
event can now excluded by the preliminary LEP 2W data.


title:
Exploring the Invisible Renormalon: Renormalization of the Heavy-Quark
  Kinetic Energy

abstract:
  Using the virial theorem of the heavy-quark effective theory, we show that
the mixing of the operator for the heavy-quark kinetic energy with the identity
operator is forbidden at the one-loop order by Lorentz invariance. This
explains why such a mixing was not observed in several one-loop calculations
using regularization schemes with a Lorentz-invariant UV regulator, and why no
UV renormalon singularity was found in the matrix elements of the kinetic
operator in the bubble approximation (the ``invisible renormalon''). On the
other hand, we show that the mixing is not protected in general by any
symmetry, and it indeed occurs at the two-loop order. This implies that the
parameter $\lambda_1^H$ of the heavy-quark effective theory is not directly a
physical quantity, but requires a non-perturbative subtraction.


title: Baryon Instability in SUSY Models

abstract:
  A review is given of nucleon instability in SUSY models. The minimal SU(5)
model is discussed in detail.


title: Inclusive Production of $t\bar{t}$ Pairs in Hadronic Collisions

abstract:
  We summarize our calculation of the total cross section for top quark
production at hadron colliders within the context of perturbative quantum
chromodynamics, including resummation of the effects of initial-state soft
gluon radiation to all orders in the strong coupling strength.


title:
Physical and Cosmological Implications of a Possible Class of Particles
  Able to Travel Faster than Light

abstract:
  If Lorentz invariance is only an approximate property of equations describing
a sector of matter above some critical distance scale, the speed of light c
will not necessarily be the only critical speed in vacuum. Superluminal sectors
of matter may exist related to new degrees of freedom not yet discovered
experimentally. The new particles would not be tachyons: they may feel
different minkowskian space-times with critical speeds much higher than c and
behave kinematically like ordinary particles apart from the difference in
critical speed. We present a discussion of possible physical (theoretical and
experimental) and cosmological implications of such a scenario, assuming that
the superluminal sectors couple weakly to ordinary matter.

categories: hep-ph astro-ph gr-qc hep-th physics.gen-ph


title: Spin and Weak Interactions in Atoms and Nuclei

abstract:
  The use of spin observables to study the semi-leptonic and non-leptonic weak
interaction in atoms and nuclei is surveyed. In particular, the use of
semi-leptonic neutral current scattering and atomic parity violation to search
for physics beyond the Standard Model is reviewed. The status of nuclear parity
violation as a probe of the weak N-N interaction is surveyed. Possible atomic
and nuclear signatures of parity conserving, time-reversal violating
interactions are also discussed.


title: PQCD Analysis of Hard Scattering in Nuclei

abstract:
  We review the extension of the factorization formalism for perturbative QCD
to soft initial- and final-state scattering associated with hard processes in
nuclei.


title: Resonant decay of Bose condensates

abstract:
  We present results of fully non-linear calculations of decay of the inflaton
interacting with another scalar field X. Combining numerical results for
cosmologically interesting range of resonance parameter, q \leq 10^6, with
analytical estimates, we extrapolate them to larger q. We find that scattering
of X fluctuations off the Bose condensate is a very efficient mechanism
limiting growth of X fluctuations. For a single-component X, the resulting
variance, at large q, is much smaller than that obtained in the Hartree
approximation.


title: Factorization in non-leptonic decays of heavy mesons

abstract:
  We propose a QCD-based model for calculation of the non-perturbative
corrections to the factorization approximation in the decays of heavy mesons.
In the framework of the model, factorization in pseudoscalar transitions holds
exactly at the leading order leaving the opportunity to calculate non-leading
corrections consistently.


title: Kinetic Mixing and the Supersymmetric Gauge Hierarchy

abstract:
  The most general Lagrangian for a model with two U(1) gauge symmetries
contains a renormalizable operator which mixes their gauge kinetic terms. Such
kinetic mixing can be generated at arbitrarily high scales but will not be
suppressed by large masses. In models whose supersymmetry (SUSY)-breaking
hidden sectors contain U(1) gauge factors, we show that such terms will
generically arise and communicate SUSY-breaking to the visible sector through
mixing with hypercharge. In the context of the usual supergravity- or
gauge-mediated communication scenarios with D-terms of order the fundamental
scale of SUSY-breaking, this effect can destabilize the gauge hierarchy. Even
in models for which kinetic mixing is suppressed or the D-terms are arranged to
be small, this effect is a potentially large correction to the soft scalar
masses and therefore introduces a new measurable low-energy parameter. We
calculate the size of kinetic mixing both in field theory and in string theory,
and argue that appreciable kinetic mixing is a generic feature of string
models. We conclude that the possibility of kinetic mixing effects cannot be
ignored in model-building and in phenomenological studies of the low-energy
SUSY spectra.


title: Calculations of Higher Twist Distribution Functions in the MIT Bag Model

abstract:
  We calculate all twist-two, three and four parton distribution functions
involving two quark correlations using the wavefunction of the MIT bag model.
The distributions are evolved up to experimental scales and combined to give
the various nucleon structure functions. Comparisons with recent experimental
data on higher twist structure functions at moderate values of $Q^{2}$ give
good agreement with the calculated structure functions.


title: Quasi-degenerate neutrinos from an abelian family symmetry

abstract:
  We show that models with an abelian family symmetry which accounts for the
observed hierarchies of masses and mixings in the quark sector may also
accomodate quasi-degeneracies in the neutrino mass spectrum. Such approximate
degeneracies are, in this context, associated with large mixing angles. The
parameters of this class of models are constrained. We discuss their
phenomenological implications for present and foreseen neutrino experiments.


title: Estimate of $\alpha_s(m_Z)$ in sum rules for bottomonium

abstract:
  The value of $\alpha_s(m_Z)=0.106\pm 0.005$ is obtained in a scheme of sum
rules for the leptonic constants of the vector $nS$-levels in the heavy $(\bar
b b)$-quarkonium.


title: Structures in Multiplicity Distributions and Oscillations of Moments

abstract:
  The possibility to relate multiplicity distributions and their moments, as
measured in the hadronic final state in e(+)e(-) annihilation, to features of
the initial partonic state is analyzed from a theoretical and phenomenological
point of view. Recent developments on the subject are discussed.


title: Strangeness Dependence in Radiative Hyperon Decay Amplitudes

abstract:
  The radiative decays of the $(3/2)^+$ baryons are studied in the three flavor
generalization of the Skyrme model. The kaon fields are treated in the slow
rotator approach which properly accounts for the observed deviations from the
$U$-spin relations for the hyperon magnetic moments. This makes possible a
critical discussion of the $U$-spin selection rules for the radiative hyperon
decays. The variation of the decay widths with strangeness is studied and a
comparison with other treatments of the $SU(3)$ Skyrme model is performed in
order to analyze the effects of flavor symmetry breaking.


title: Electric dipole moments from Yukawa phases in supersymmetric theories

abstract:
  We study quark and electron EDMs generated by Yukawa couplings in
supersymmetric models with different gauge groups, using the EDM properties
under flavour transformations. In the MSSM (or if soft terms are mediated below
the unification scale) the one loop contributions to the neutron EDM are
smaller than in previous computations based on numerical methods, although
increasing as tan^3\beta. A neutron EDM close to the experimental limits can be
generated in SU(5), if tan\beta is large, through the u-quark EDM d_u,
proportional to tan^4\beta. This effect has to be taken into account also in
SO(10) with large tan\beta, where d_u is comparable to the d-quark EDM,
proportional to tan\beta.


title:
Meson Production and Bose-Einstein Pion Correlations in High Energy
  Collisions

abstract:
  The pion Bose-Einstein correlation parameters determined by OPAL show a weak
dependence on pion multiplicity. We argue that the observed increase of the
interaction radius, and the decrease of the chaoticity parameter could be due
to an increasing fraction of other mesons at high multiplicities.


title:
Left-right asymmetry and polarization for inclusive hyperon production
  processes

abstract:
  It is shown that the polarization in inclusive hyperon production and the
left-right asymmetries in meson and hyperon production are closely related to
one other. They can be understood in terms of a picture in which the orbital
motion of valence quarks of the scattering hadrons play an important role.


title: Spin-effects and dissociation of space-like photons

abstract:
  Talk presented by Meng Ta-chung at the 12th International Symposium on High
Energy Spin Physics, SPIN96, Amsterdam, September 10-14,1996.


title:
Inclusive Two-Jet Production in Photon-Photon Collisions: Direct and
  Resolved Contributions in Next-to-Leading Order QCD

abstract:
  We have calculated inclusive two-jet production in photon-photon collisions
superimposing direct, single-resolved and double-resolved cross sections for
center-of-mass energies of TRISTAN and LEP1.5. All three contributions are
calculated up to next-to-leading order. The results are compared with recent
experimental data. Three NLO sets of parton distributions of the photon are
tested.


title: Squark and Gluino Production at Hadron Colliders

abstract:
  We have determined the theoretical predictions for the cross-sections of
squark and gluino production at $\ppb$ and $pp$ colliders (Tevatron and LHC) in
next-to-leading order of supersymmetric QCD. By reducing the dependence on the
renormalization/factorization scale considerably, the theoretically predicted
values for the cross-sections are much more stable if these higher-order
corrections are implemented. If squarks and gluinos are discovered, this
improved stability translates into a reduced error on the masses, as extracted
experimentally from the size of the production cross-sections. The
cross-sections increase significantly if the next-to-leading order corrections
are included at a renormalization/factorization scale near the average mass of
the produced massive particles. This rise results in improved lower bounds on
squark and gluino masses. By contrast, the shape of the transverse-momentum and
rapidity distributions remains nearly unchanged when the next-to-leading order
corrections are included.


title: Worldline description of the Isgur-Wise function

abstract:
  An effective field theoretic description of the Isgur-Wise function in
heavy-meson transitions is presented which emulates soft interactions by a
fermion worldline with an infinitesimal self-intersecting loop. A
point-splitting regularization technique is used, which replaces pointlike
worldlines by ``ribbons'' in the sense of Witten. The calculated vertex
function is correctly normalized, does not depend on the heavy-quark mass, and
complies with different sets of recent experimental data of the ARGUS and CLEO
collaborations.


title: A Quick Look at Renormalons

abstract:
  We present a sketchy review of renormalon-based phenomenology. In particular,
the leading, 1/Q corrections to various observables, KLN cancellations for
power-suppressed corrections and the fixation of operator matrix elements are
highlighted.


title:
Light Gluino Contribution in Hadronic Decays of Z boson and tau lepton
  to O(alpha_s^3)

abstract:
  The results of calculation of light gluino contributions to
Gamma(Z--->hadrons) and Gamma(tau--->hadrons) to O(alpha_s^3) are presented.
The net effect in the case of Z decay is noticeable. For the tau width the
effect is very large and, if a light gluino exists, suggests that alpha_s
increases by more than 15% relative to the Standard Model analysis.


title: Neutrino oscillations in curved spacetime: an heuristic treatment

abstract:
  We discuss neutrino oscillations in curved spacetime. Our heuristic approach
can accomodate matter effects and gravitational contributions to neutrino spin
precession in the presence of a magnetic field. By way of illustration, we
perform explicit calculations in the Schwarzschild geometry. In this case,
gravitational effects on neutrino oscillations are intimately related to the
redshift. We discuss how spacetime curvature could affect the resonance
position and adiabaticity of matter-enhanced neutrino flavor conversion.


title:
Detecting and Studying $e^+e^-\to H^0A^0,H^+H^-$ in the MSSM:
  Implications of Supersymmetric Decays and Discriminating GUT Scenarios

abstract:
  We demonstrate that supersymmetric decays, as typified by the predictions of
several GUT-scale boundary condition choices, do not prevent detection of $Z^*
\to H^0A^0,H^+H^-$, at a $1-4$ TeV $e^+e^-$ or $\mu^+\mu^-$ collider operating
at anticipated luminosity. For much of parameter space the relative branching
ratios for various SUSY and non-SUSY decays can be measured with sufficient
accuracy that different GUT-scale boundary condition choices can be
distinguished from one another at a very high confidence level.


title: Strange Baryonic Matter from Chiral Effective Lagrangians

abstract:
  We investigate the existence of bound states of baryons in a kaon condensate
using chiral mean field theory.
  The interactions are described by an effective SU(3)_L X SU(3)_R chiral
lagrangian where terms of higher order in density, baryon momentum, and kaon
mass are suppressed by powers of the symmetry breaking scale, Lambda. We take
up to next to leading order terms (n = 2,3,4). We search for infinite baryon
number solutions, namely ``strange baryonic matter'', using a Thomas-Fermi
approximation for a slowly varying condensate and a lowest order Hartree
approximation to describe the many body interactions. For simplicity we study a
pure K^0 condensate and only neutrons, the lightest baryons in that condensate.
We find solutions with neutron number densities, rho_n > 3.5 rho_0, where rho_0
is the infinite nuclear matter density. This is consistent with the estimate of
the onset of a K-condensate at rho_n = 2-4 rho_0. We show that the binding
energies, E_b, grow with rho_n and for rho_n < 7 rho_0 (at rho_n > 7 rho_0
perturbative expansion is lost) we find E_b < 150 MeV (E_b < 70 MeV for rho_n <
5 rho_0) even in the most favorable cases. These binding energies may be too
low for this type of matter to appear and persist in the early universe.


title: Isolated Prompt Photon Cross Sections

abstract:
  We show that the conventionally defined partonic cross section for the
production of isolated prompt photons is not an infrared safe quantity. We work
out the case of $e^+e^-\to\gamma + X$, and discuss implications for hadron
reactions.


title: Calculation of QCD jet cross sections at next-to-leading order

abstract:
  A general method for calculating \NLO cross sections in perturbative QCD is
presented. The algorithm is worked out for calculating $N$-jet cross sections
in hadron-hadron collisions. The generalization of the scheme to performing
caclulations for other QCD process, such as electron-positron annihilation or
in deep inelastic scattering is also straightforward. As an illustration
several three-jet cross section distributions in electron-positron
annihilation, calculated using the algorithm, are presented.


title:
Three-jet cross section in hadron collisions at next-to-leading order:
  pure gluon processes

abstract:
  The next-to-leading order three-jet cross section in hadron collisions is
calculated in the simplified case when the matrix elements of all QCD
subprocesses are approximated by the pure gluon matrix element. The
longitudinally-invariant $k_\perp$ jet-clustering algorithm is used. The
important property of reduced renormalization and factorization scale
dependence of the next-to-leading order physical cross section as compared to
the Born cross section is demonstrated.


title: Theoretical Aspects of Higgs Physics

abstract:
  We review the present status of Higgs physics within the standard model and
its extensions. First, we briefly summarize the current experimental exclusion
limits from the direct searches with LEP1 and the Tevatron, and assess the
discovery potential of LEP2. Then, we report the mass bounds resulting from
global fits to the latest electroweak precision data, and compile various
theoretical principles which lead to restrictions - or even determinations - of
the Higgs-boson masses. Perturbative upper bounds are discussed in some detail.
Finally, we survey the recent progress in the computation of higher-order
radiative corrections to the bb-bar decay width of the standard-model Higgs
boson.


title: Probing Supersymmetry in Rare B Decays

abstract:
  We determine the ability of future experiments to observe supersymmetric
contributions to the rare decays $B \to X_s \gamma$ and $B \to X_s l^+l^-$. A
global fit to the Wilson coefficients which contribute to these decays is
performed from Monte Carlo generated data. This fit is then compared to
supersymmetric predictions for several different patterns of the superpartner
spectrum.


title: Prompt Photon plus Charm Production at Next-to-Leading Order in QCD

abstract:
  The two particle inclusive cross section for the reaction $p
+\bar{p}\rightarrow \gamma + c + X$ is studied in perturbative quantum
chromodynamics at order $O(\alpha ^2_s)$. Differential distributions are
provided for various observables, and a comparison is made with data from the
CDF collaboration.


title: Virtual SUSY Threshold Effects and CDF large $E_{T}$ Anomaly

abstract:
  Recent CDF data of the inclusive jet cross section shows threshold-like
structured deviation, around transverse momentum $E_T(j)\approx 200 \sim 350$
GeV. If this data is real, not just some statistical fluctuation, is it
possible to interpret the anomaly in terms of virtual SUSY effects? The purpose
of this note is to address this question. However, we find that virtual SUSY
loop interference effects [near the threshold] are too small to explain the CDF
data. Our main conclusion seems to be on the right track if we assume that the
recent global analysis of improved parton distributions by Lai et al. is
correct. PACS number(s): 14.65.Ha, 12.38.Bx, 12.60.Jv, 13.85.-t


title:
The $\mu$ problem, and B and L Conservation with a Discrete Gauge R
  Symmetry

abstract:
  We examine in a generic context how the $\mu$ problem can be resolved by
means of a spontaneously broken gauge symmetry. We then focus on the new scheme
based on a discrete gauge R symmetry which is spontaneously broken by
nonperturbative hidden sector dynamics triggering supersymmetry breaking also.
The possibility to suppress the dangerous baryon and/or lepton number violating
interactions by means of this discrete R symmetry is examined also together
with some phenomenological consequences.


title: Quarkonium production via fragmentation: A review

abstract:
  We review the physics of quarkonium production at high energy colliders, with
a specific emphasis on production $via$ fragmentation. We discuss the
fragmentation picture for the production of quarkonia at large-$p_T$ at the
Tevatron and emphasise the importance of the colour-octet components of the
quarkonium wave function which are included in the fragmentation functions.
Applications of these theoretical ideas to other processes, both at the
Tevatron and at other experiments like LEP, HERA and the LHC are important as
they will provide stringent tests of these ideas.


title: Vector Leptoquark Pair Production in $e^+e^-$ Annihilation

abstract:
  The cross section for vector leptoquark pair production in $e^+e^-$
annihilation is calculated for the case of finite anomalous gauge boson
couplings $\kappa_{\gamma, Z}$ and $\lambda_{\gamma, Z}$. The minimal cross
section is found to behave $\propto \beta^7$, leading to weaker mass bounds in
the threshold range than in models studied previously.


title: Primordial Nucleosynthesis, Majorons and Heavy Tau Neutrinos

abstract:
  We determine the restrictions imposed by primordial nucleosynthesis upon a
heavy tau neutrino, in the presence of nu-tau annihilations into Majorons, as
expected in a wide class of particle physics models of neutrino mass. We
determine the equivalent number of light neutrino species $N_{eq}$ as a
function of nu-tau mass and the nu-tau-Majoron coupling $g$. We show that for
theoretically plausible $g$ values $\gsim 10^{-4}$ present nucleosynthesis
observations can not rule out nu-tau masses in the MeV range. Moreover, these
models give $N_{eq} \leq 3$ in the nu-tau mass region 1-10 MeV, for very
reasonable values of $g \geq 3 \times 10^{-4}$. The evasion of the cosmological
limits brings new interest to the improvement of the present laboratory limit
on the nu-tau mass which can be achieved at a tau-charm factory.


title: Quark Masses and Mixing Angles

abstract:
  Inspired by the vector-like phenomenon of chiral gauge theories at short
distances, we postulate that the $W^\pm$-gauge boson has a vector-like gauge
coupling in the high-energy region, beside its purely right-handed gauge
coupling observed in the low-energy region. It is discussed that the top quark
acquires its mass via spontaneous symmetry breaking, while the $u,d,c,s,b$
quarks acquire their masses via explicit symmetry breakings. We discover four
relationships between four inter-generation mixing angles and six quark masses
by examining Dyson equations for quark self-energy functions. A preliminary
analysis shows that the hierarchical pattern of quark masses is closely related
to the hierarchical pattern of inter-generation mixing angles. In particular,
the CP-violating phase is predicted to be approximately 79$^\circ$.


title: Constraints on Z' from W^+W^- production at the NLC with polarized beams

abstract:
  We discuss the potential of NLC500 and NLC1000 to probe Z-Z' mixing and mass
by the reaction e^+e^- -> W^+W^- with longitudinally polarized electrons. We
perform a model-independent analysis of the deviations from the Standard Model,
and apply it to a specific class of extended weak gauge models. Results
indicate that the corresponding bounds at the NLC500 complement the present
ones obtained from LEP1, and rapidly become quite stringent at the higher
energy of the NLC1000. Also, we emphasize the importance of initial beam
polarization in improving the sensitivity to mixing.


title: Some techniques for calculating two-loop diagrams

abstract:
  A brief overview of some recent publications related to the evaluation of
two-loop Feynman diagrams is given. (Talk given at the International Symposium
on Radiative Corrections CRAD96, Cracow, Poland, 1--5 August 1996)


title:
Renormalization of the meson-baryon SU(3) Lagrangian in chiral
  perturbation theory to order q^3

abstract:
  We perform the complete regularization of all Green functions with a single
incoming and outgoing baryon to order q^3 in the low energy expansion for the
SU(3) meson-baryon system in chiral perturbation theory. The divergences can be
extracted in a chiral invariant manner by making use of the heat kernel
representation of the propagators in d-dimensional Euclidean space.


title:
Implications of anomalous gauge boson interactions to the fermion
  electromagnetic moments

abstract:
  We calculate the electromagnetic fermion form-factors induced by the
anomalous gauge boson interactions contained in the operators ODW and ODB.
Other results regarding anomalous triple gauge boson interactions are briefly
overviewed. We study the interplay between vertex corrections and gauge boson
self-energies extended to the longitudinal degrees of freedom. The physical
couplings to an external electromagnetic field are then derived.


title: Study of Z' Couplings to Leptons and Quarks at NLC

abstract:
  The discovery of a Z' and the measurement of Z' couplings to fermions are
main tasks of future colliders. Here, the possibilities to measure Z' f \bar f
couplings at an NLC operating below a Z' resonance are studied. In dependence
on the mass of the Z' and the collider parameters one will be able to
discriminate between Z' models.


title:
Constraints on the Charged Higgs Sector from the Tevatron Collider Data
  on Top Quark Decay

abstract:
  The top quark data in the lepton plus $\tau$ channel offers a viable probe
for the charged Higgs boson signal. We analyse the recent Tevatron collider
data in this channel to obtain a significant limit on the $H^\pm$ mass in the
large $\tan\beta$ region.


title:
Chiral Symmetry Breaking, Duality in the \bar{Q}q Channel and b -> c
  anti-c s Decays

abstract:
  We address the issue of the quark-hadron duality in the spectral densities
induced by the heavy-light quark currents anti-Q q. In the limit m_Q ->oo, m_q
->0 we observe an enhancement of the physical spectral density compared to the
quark one in the scalar and axial channels, due to the Goldstone meson
contributions. This may imply that the scale where duality sets in is higher in
these channels than in the vector (pseudoscalar) case. Implications for the
nonleptonic decays of B mesons (the b -> c anti-c s transition) are considered.
We discuss in detail the decay pattern and obtain an independent estimate of
the "wrong" sign D yield.


title: Future Directions for QCD

abstract:
  New directions for exploring QCD at future high-energy colliders are
sketched. These include jets within jets, BFKL dynamics, soft and hard
diffraction, searches for disoriented chiral condensate, and doing a better job
on minimum bias physics. The new experimental opportunities include
electron-ion collisions at HERA, a new collider detector at the C0 region of
the TeVatron, and the FELIX initiative at the LHC.


title: Yukawa Textures in String Unified Models With SU(4)xO(4) Symmetry

abstract:
  We discuss the origin of Yukawa textures in the string-inspired and string
derived models based on the gauge group SU(4)xSU(2)_LxSU(2)_R supplemented by a
U(1)_X gauged family symmetry. The gauge symmetries are broken down to those of
the minimal supersymmetric standard model which is the effective theory below
10^16 GeV. The combination of the U(1)_X family symmetry and the Pati-Salam
gauge group leads to a successful and predictive set of Yukawa textures
involving two kinds of texture zeroes: horizontal and vertical texture zeroes.
We discuss both symmetric and non-symmetric textures in models of this kind,
and in the second case perform a detailed numerical fit to the charged fermion
mass and mixing data. Two of the Yukawa textures allow a low energy fit to the
data with a total chi^2 of 0.39 and 1.02 respectively, for three degrees of
freedom. We also make a first attempt at deriving the non - renormalisable
operators required for the Yukawa textures from string theory.


title: Corrections to the Bjorken and Voloshin sum rules

abstract:
  We calculate near zero recoil the order $\alpha_s$ corrections to the Bjorken
and Voloshin sum rules that bound the $B\to D^{(*)}\ell\bar\nu$ form factors.
These bounds are derived by relating the result of inserting a complete set of
physical states in a time ordered product of weak currents to the operator
product expansion. The sum rules sum over physical states with excitation
energies less than a scale $\Delta$. We find that the corrections to the
Bjorken bound are moderate, while the Voloshin bound receives sizable
corrections enhanced by $\Delta/\Lambda_{QCD}$. With some assumptions, we find
that the slope parameter for the form factor $h_{A_1}$ in $B\to D^*\ell\bar\nu$
decay satisfies $0.4\lesssim\rho_{A_1}^2 \lesssim 1.3$.


title: Euclidean Solutions in Broken Phase and Electro-Weak Dynamics

abstract:
  A Higgs-Yukawa system in a broken phase and Euclidean solutions are
investigated. Although it has been believed that there are no Euclidean
solutions in the broken phase in 4-dimension, we find numerically ones in the
phase due to the effect of a strong Yukawa coupling. The complex Yukawa
coupling is necessary for the stability of the solution. The extension to a
complex Higgs-Yukawa system is also investigated.


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

abstract:
  The \pi NN^* and \eta NN^* coupling constants are studied based on the two
point functions between the vacuum and a one meson state in the soft meson
limit. In terms of a suitably constructed interpolating field for the nucleon
and resonances, we have found that the \pi NN^* couplings vanish, while \eta
NN^* couplings remain finite. This result explains a relatively suppressed
coupling of \pi NN(1535) as compared with others. We compare the present result
with predictions of low energy effective models.


title:
Numerical solution of NLO Q^2 evolution equations for spin-dependent
  structure functions

abstract:
  Numerical solution of DGLAP $Q^2$ evolution equations is studied for
polarized parton distributions by using a ``brute-force" method. NLO
contributions to splitting functions are recently calculated,and they are
included in our analysis. Numerical results in polarized parton distributions
and in the structure function $g_1$ are shown. In particular, we discuss how
numerical accuracy depends on number of steps in the variable $x$ and in $Q^2$.


title: Cascade Mixing, a New Kind of Particle Mixing Phenomenon

abstract:
  We discuss ``cascade mixing", where one particle mixture, say a B0, leads to
another, say a K0. A simple analysis is possible in the amplitude approach,
which avoids ``collapses of the wavefunction" and is explicitly covariant. Some
novel possibilities, both of conceptual and perhaps of experimental interest,
arise. For example, we explain how such processes can allow one to ``tune", in
principle, the phase relations in a particle mixture. Also, effects arise
involving combinations of the mass differences of two particle mixtures. We
explain how an intermediate measurement may play the role of a regenerator, so
that in principle regeneration-like effects can be induced for the B0 and D0
systems, despite their short flight paths. The analysis of such process with
respect to CP and the distinction between ``direct" and ``indirect" CP
violation is discussed.


title:
Three-body dispersion-relation N/D equations for the coupled decay
  channels ppbar (J^{PC}=0^{-+}) --> pi^0 pi^0 pi^0, eta pi^0 pi^0, eta eta
  pi^0, K Kbar pi^0

abstract:
  During several years the data on different channels ppbar (J^{PC}=0^{-+}) -->
3 mesons presented by Crystal Barrel Collaboration were successfully analyzed
by extracting the leading amplitude singularities - pole singularities - with
the aim to obtain information about two-meson resonances. But these analyses do
not take into account three-body final state interactions (FSI) in an
explicitly correct way. This paper is devoted to the consideration of this
problem.


title: The transverse polarization distribution $h_1(x,Q^2)$

abstract:
  We report the results of a quark model calculation of the transverse
polarization distribution $h_1$. Predictions for the Drell-Yan double spin
transverse asymmetry are also presented.


title: Final State Interactions in $B -> D \rho$ and $B -> D^{*}\pi$ Decays

abstract:
  We analyze final state strong interaction effects in $B -> D \rho$ and $B ->
D^{*}\pi$ decays using the Regge model. We find that, due to the smallness of
the contributions from the non-leading Regge trajectories ($\rho$, $f$, $\pi$
etc.), final state interaction phases are small if the Pomeron coupling to the
charm quark is suppressed in comparison to lighter quarks. Our conclusion is
that for $B$ decays into states containing charm, final state interaction
effects should play a minor role.


title:
The MSW conversion of solar neutrinos and random matter density
  perturbations

abstract:
  We present a generalization of the resonant neutrino conversion in matter,
including a random component in the matter density profile. The study is
focused on the effect of such matter perturbations upon both large and small
mixing angle MSW solutions to the solar neutrino problem. This is carried out
both for the active-active $\nu_e \to \nu_{\mu,\tau}$ as well as active-sterile
$\nu_e \to \nu_s$ conversion channels. We find that the small mixing MSW
solution is much more stable (especially in $\delta m^2$) than the large mixing
solution. Future solar neutrino experiments, such as Borexino, could probe
solar matter density noise at the few percent level.


title:
Reply to the Comment by Harada, Sannino and Schechter on "Confirmation
  of the Sigma Meson"

abstract:
  We reply to the comment of Harada, Sannino and Schechter (hep-ph/9609428) on
our recent paper in the Phys. Rev. Letters on the sigma meson. This concerns
the question, raised by Isgur and Speth in another comment, of whether a
detailed crossing symmetric form is necessary to understand the data. The
discussion gives further support on the existence of the broad sigma near 500
MeV.


title: Monte Carlo calculations for the hard Pomeron

abstract:
  Starting from the same input as the standard BFKL Pomeron, we directly
calculate the ``hard'' Pomeron as a gluonic ladder by using Monte Carlo
methods. We reproduce the characteristic features of the the BFKL Pomeron and
are now also able to evaluate new observables. The applicability of the BFKL
approach under realistic kinematical conditions can be tested and the influence
of the running coupling constant examined.


title: Theoretical aspects of W-pair production in e+e- collisions

abstract:
  The most interesting theoretical features of W-pair production in e+e-
collisions are reviewed. Based on an analysis of on-shell W-pairs, it is shown
that the mere inclusion of leading $O(\alpha)$ corrections--such as
initial-state radiation, effects from the universal quantities $\Delta\alpha$
and $\Delta r$, and the Coulomb singularity--cannot be expected to approximate
the $O(\alpha)$-corrected cross-section of $e^+e^-\to W^+W^-\to 4f$ to better
than 1-2% for LEP2 energies. The importance of the gauge-invariance problem,
arising from the introduction of finite decay widths, is discussed. The
simplest consistent method to include $O(\alpha)$ corrections at least to the
doubly resonant contributions, viz. a pole expansion around the double
resonance, is also briefly described.


title:
The relativistic and nonrelativistic quark-antiquark bound state problem
  in a Wilson loop context

abstract:
  Taking advantage of a semirelativistic and a full relativistic representation
of the quark propagator in an external field we present an unified derivation
of the semirelativistic potential and of a Bethe-Salpeter like equation for the
quark-antiquark system. We consider three different models for the evaluation
of the Wilson loop: the Modified Area Law model (MAL), the Stochastic Vacuum
Model (SVM) and the Dual QCD (DQCD). We compare the corresponding potentials
and show that they all agree at the short and the long distances. In the case
of the Bethe-Salpeter equation we treat explicitly only the MAL model and give
an expression for the kernel. Then we show that an effective mass operator can
be obtained which agrees with the MAL potential in the semirelativistic limit.
In the light quark mass limit this mass operator produces straight Regge
trajectories with Nambu-Goto slope in agreement with the data. Finally we
briefly discuss the mass independence of the hyperfine splitting in the
heavy-light case.


title: Four and Three Loop Calculations in QCD: Theory and Applications

abstract:
  The talk briefly reviews the current state of the art in doing multiloop QCD
calculations in a completely analytic way. In particular, we discuss recent
analytical calculation of 4-loop O(alpha_s**3) gluino contribution to R(s) and
its implications to the Z boson and tau-lepton decay rates.


title: Quenched Chiral Perturbation Theory for Vector Mesons

abstract:
  We develop quenched chiral perturbation theory for vector mesons made of
light quarks, in the limit where the vector meson masses are much larger than
the pion mass. We use this theory to extract the leading nonanalytic dependence
of the vector meson masses on the masses of the light quarks. By comparing with
analogous quantities computed in ordinary chiral perturbation theory, we
estimate the size of quenching effects, observing that in general they can be
quite large. This estimate is relevant to lattice simulations, where the $\rho$
mass is often used to set the lattice spacing.


title: T-Violation in $K^+ \to \mu^+ \nu \gamma$ Decay And Supersymmetry

abstract:
  Measurement of the transverse muon polarization $P^{\bot}_{\mu}$ in the $K^+
\rightarrow \mu^+\nu\gamma$ decay will be attempted for the first time at the
ongoing KEK E246 experiment and also at a proposed BNL experiment. We provide a
general analysis of how $P^{\bot}_{\mu}$ is sensitive to the physical
$CP$-violating phases in new physics induced four-Fermi interactions, and then
we calculate the dominant contributions to $P^{\bot}_{\mu}$ from squark family
mixings in generic supersymmetric models. Estimates of the upper bounds on
$P^{\bot}_{\mu}$ are also given. It is found that a supersymmetry-induced
right-handed quark current from $W$ boson exchange gives an upper limit on
$P^{\bot}_{\mu}$ as large as a few per cent, whereas with
charged-Higgs-exchange induced pseudoscalar interaction, $P^{\bot}_{\mu}$ is no
larger than a few tenths of a per cent. Possible correlations between the muon
polarization measurements in $K^+ \rightarrow \mu^+\nu\gamma$ and $K^+
\rightarrow \pi^0\mu^+\nu$ decays are discussed, and distinctive patterns of
this correlation from squark family-mixings and from the three-Higgs-doublet
model are noted.


title: Bound States and Power Counting in Effective Field Theories

abstract:
  The problem of bound states in effective field theories is studied. A
rescaled version of nonrelativistic effective field theory is formulated which
makes the velocity power counting of operators manifest. Results obtained using
the rescaled theory are compared with known results from NRQCD. The same ideas
are then applied to study Yukawa bound states in 1+1 and 3+1 dimensions, and to
analyze when the Yukawa potential can be replaced by a delta-function
potential. The implications of these results for the study of nucleon-nucleon
scattering in chiral perturbation theory is discussed.


title:
Differences between Monte Carlo models for DIS at small-x and the
  relation to BFKL dynamics

abstract:
  The differences between two standard Monte Carlo models, Lepto and Ariadne,
for deep inelastic scattering at small-x is analysed in detail. It is shown
that the difference arises from a `unorthodox' suppression factor used in
Ariadne which replaces the normal ratio of parton densities. This gives rise to
a factor that qualitatively is similar to what one would expect from BFKL
dynamics for some observables like the energy flow and forward jets but not for
the 2+1 jet cross-section. It is also discussed how one could use the 2+1 jet
cross-section as a probe for BFKL dynamics.


title:
Relativistic effects in parity-violating electron- deuteron scattering
  and strangeness in the nucleon

abstract:
  Deuteron electrodisintegration is described in a relativistic PWIA framework.
The reduction to the factorized PWIA, and the effect thereof on the observables
accessible in parity-violating scattering, is discussed. The extent to which
such relativistic effects may affect the extraction of strangeness nucleon form
factors from measurements of the PV asymmetry, is investigated.


title: Small $P_{\perp}^2$ Elastic Proton-Proton Polarization near 300 GeV

abstract:
  Using two hopefully reasonable assumptions plus existing data on the
analyzing power in high energy proton-proton elastic scattering, we estimate
that the hadronic helicity-flip amplitude at $P^2_{\perp}$ of 0.003 (GeV/c)$^2$
is neglible near 300 GeV. This would allow the absolute calibration of a CNI
polarimeter.


title: The constituent quark as a soliton in a linear sigma-model

abstract:
  We study a stable, soliton-like solution in the linear $\sigma$-model where
the chiral fields are coupled to a single massless nonstrange quark. We
investigate a possibility that this solution represents the constituent quark
of Georgi and Manohar. We show that its properties are indeed consistent with
nucleon observables. Furthermore, we derive chiral meson exchange potentials
between such objects which are similar to recently used potentials in the
constituent quark models.


title: Coupling Gravity and the Standard Model: a Conformal Approach

abstract:
  In 1992 Professor Ryszard R\c{a}czka started to work on formulation of a
version of the Standard Model conformally coupled with gravity. Being his
student I had got the honour to participate in those researches. The
conformally invariant Higgs-Free Model was the result of our investigations.
Ryszard R\c{a}czka passed away on 26 August 1996. I present here a short
memorial survey of our results.


title:
Renormalization Group Induced Neutrino Mass in Supersymmetry without
  R-parity

abstract:
  We study supersymmetric models without R parity and with universal soft
supersymmetry breaking terms. We show that as a result of the renormalization
group flow of the parameters, a misalignment between the directions in field
space of the down-type Higgs vacuum expectation value $v_d$ and of the $\mu$
term is always generated. This misalignment induces a mixing between the
neutrinos and the neutralinos, resulting in one massive neutrino. By means of a
simple approximate analytical expression, we study the dependence on the
different parameters that contribute to the misalignment and to $m_\nu$. In
large part of the parameter space this effect dominates over the standard
one-loop contributions to $m_\nu$; we estimate 1 MeV $\lsim m_\nu \lsim 1 GeV$.
Laboratory, cosmological and astrophysical constraints imply $m_\nu \lsim 100
eV$. To be phenomenologically viable, these models must be supplemented with
some additional mechanism to ensure approximate alignment and to suppress
$m_\nu$.


title: Production of a Higgs Boson Plus Two Jets in Hadronic Collisions

abstract:
  We consider the production of a Standard Model Higgs boson accompanied by two
jets in hadronic collisions. We work in the limit that the top quark is much
heavier than the Higgs boson and use an effective Lagrangian for the
interactions of gluons with the Higgs boson. In addition to the previously
computed four-gluon process, we compute the the amplitudes involving two
quarks, two gluons and the Higgs boson and those involving four quarks and the
Higgs boson. We exhibit the form of our results in the small-p_H and
factorization limits. We present numerical results for root S of 14 TeV and
root S of 2 TeV. We find that the dominant processes are gg -> ggH and qg -> qg
H with the former (latter) contributing about 60% (40%) of the cross section at
root S of 14 TeV and the two processes each contributing about half the cross
section at root S of 2 TeV. All other processes are negligible at both
energies.


title: Status of Solar Models

abstract:
  The neutrino fluxes calculated from 14 standard solar models published
recently in refereed journals are inconsistent with the results of the 4
pioneering solar neutrino experiments if nothing happens to the neutrinos after
they are created in the solar interior. The sound speeds calculated from
standard solar models are in excellent agreement with helioseismological
measurements of sound speeds. Some statements made by Dar at Neutrino 96 are
answered here.


title:
Nonperturbative QCD Contributions to the Semileptonic Decay Width of the
  B Meson

abstract:
  Nonperturbative QCD contributions to the inclusive semileptonic decay of the
B meson consist of the dynamic and kinematic components. We calculate the decay
width in an approach based on the light-cone expansion and the heavy quark
effective theory, which is able to include both components of nonperturbative
QCD contributions. The kinematic component results in the phase-space extension
and is shown to be quantitatively crucial, which could increase the decay width
significantly. We find that the semileptonic decay width is enhanced by
long-distance strong interactions by +(9\pm 6)%. This analysis is used to
determine the CKM matrix element |V_{cb}| with a controlled theoretical error.
Implications of the phase-space effects for the nonleptonic decay widths of b
hadrons are briefly discussed. The experimental evidence for the phase-space
effects is pointed out.


title: Precision SUSY Measurements at LHC

abstract:
  If supersymmetry exists at the electroweak scale, then it should be
discovered at the LHC. Determining masses, of supersymmetric particles however,
is more difficult. In this paper, methods are discussed to determine
combinations of masses and of branching ratios precisely from experimentally
observable distributions. In many cases such measurements alone can greatly
constrain the particular supersymmetric model and determine its parameters with
an accuracy of a few percent. Most of the results shown correspond to one year
of running at LHC at ``low luminosity'.


title: A demonstration that the observed neutrinos are not Majorana particles

abstract:
  Please see revised version hep-ph/0108052. The ps version of the manuscript
contains the original abstract and body.


title:
Gauge Symmetry Breaking through Soft Masses in Supersymmetric Gauge
  Theories

abstract:
  Effects of soft breaking in N=1 supersymmetric gauge theories are studied.
For N_f < N_c, we include the dynamics of the non-perturbative superpotential
and use the original (s)quark and gauge fields. For N_f > N_c +1, we formulate
the dynamics in terms of dual (s)quarks and a dual gauge group SU(N_f-N_c). The
mass squared of the squarks can be negative triggering spontaneous breakdown of
flavor and color symmetry. The general condition for stability of the vacuum is
derived. We determine the breaking pattern, determine the spectrum and argue
that the masses vary smoothly as one crosses from the Higgs phase into the
confining phase, thus exhibiting complementarity.


title: Relating Quarkonium Wave Functions at the Origin

abstract:
  Within the context of nonrelativistic potential models, we obtain several
formulas (with varying degrees of rigor) relating the wave functions at the
origin of the $c{\bar c}$, $b{\bar c}$ and $b{\bar b}$ S-wave quarkonium
systems. One of our main results is a model-independent relation which seems to
hold to within 3% for any reasonable choice of interquark potential and any
choice of radial quantum number -- namely, ${|\Psi_{b{\bar c}}(0)|^2 \simeq
|\Psi_{c{\bar c}}(0)|^{1.3}|\Psi_{b{\bar b}}(0)|^{0.7}}$ (the exponents are
motivated in the text). One of the physical consequences of this result is the
following relationship between heavy meson masses which we expect to hold at
about the 10% level: ${M_{B_c^*}-M_{B_c}\simeq (0.7)(M_{J/\psi}
-M_{\eta_c})^{0.65}(M_{\Upsilon}-M_{\eta_b})^{0.35}}$.


title: Antigraviting Bubbles with the Non-Minkowskian Asymptotics

abstract:
  The conventional approach describes the spherical domain walls by the same
state equation as the flat ones. In such case they also must be gravitationally
repulsive, what is seemingly in contradiction with Birkhoff's theorem. However
this theorem is not valid for the solutions which do not display Minkowski
geometry in the infinity. In this paper the solution of Einstein equations
describing the stable gravitationally repulsive spherical domain wall is
considered within the thin-wall formalism for the case of the non-Minkowskian
asymptotics.


title: Chiral Effective Lagrangian in the large-Nc limit: the nonet case

abstract:
  A U_L(3) \otimes U_R(3) low-energy effective lagrangian for the nonet of
pseudogoldstone bosons that appear in the large-Nc limit of QCD is presented
including terms up to four derivatives and explicit symmetry breaking terms up
to quadratic in the quark masses. The one-loop renormalization of the couplings
is worked out using the heat-kernel technique and dimensional renormalization.
The calculation is carried through for U_L(n_l) \otimes U_R(n_l), thus allowing
for a generic number n_l of light quark flavours. The crucial advantages that
the expansion in powers of 1/N_c bring about are discussed. Special emphasis is
put in pointing out what features are at variance with the SU_L \otimes SU_R
results when the singlet \eta' is included in the theory.


title: The soft limit of the energy spectra in QCD jets

abstract:
  A scaling law for the one-particle invariant density E dn/d^3p at small
momenta is observed in experimental data. We show that these results are
consistent with the predictions of the analytical QCD approach, based on
Modified Leading Log Approximation plus Local Parton Hadron Duality, which
includes colour coherence in soft gluon bremsstrahlung.


title: Anomalous Quark Chromomagnetic Moment Induced by Instantons

abstract:
  It is shown that the quark-gluon interaction induced by instantons leads to
the quark anomalous chromomagnetic moment. In the instanton-liquid model for
the QCD vacuum, the chromomagnetic moment is $\mu_a=-\frac{\pi f}{2\alpha_s}$,
where f is the packing fraction of instantons in the vacuum.


title: Jet Fractions in e+e- Annihilation

abstract:
  The jet fractions expected in e+e- annihilation are calculated analytically
in the leading log approximation up to 6 jet order for both the JADE and Durham
algorithms.


title: Regularization Scheme Independence and Unitarity in QCD Cross Sections

abstract:
  When calculating next-to-leading order QCD cross sections, divergences in
intermediate steps of the calculation must be regularized. The final result is
independent of the regularization scheme used, provided that it is unitary. In
this paper we explore the relationship between regularization scheme
independence and unitarity. We show how the regularization scheme dependence
can be isolated in simple universal components, and how unitarity can be
guaranteed for any regularization prescription that can consistently be
introduced in one-loop amplitudes. Finally, we show how to derive transition
rules between different schemes without having to do any loop calculations.


title: QCD evolution with longitudinal fields and heavy quarks

abstract:
  QCD evolution equations that naturally include longitudinal (non-propagating)
fields and heavy quarks are derived. We start with the integral equations of
quantum field kinetics and obtain the master equations, similar to DGLAP
evolution equations after several consecutive approximations. We demonstrate
that in their primary form, the evolution equations include a new element,
feed-back via longitudinal fields, leading to a low-x enhancement in the e-p
DIS cross section. We show that the structure function F_L is very sensitive to
the dynamics of the longitudinal fields and that the heavy quarks in evolution
equations make this effect even more pronounced.


title:
Weakly first-order phase transitions: the epsilon expansion vs.
  numerical simulations

abstract:
  Some phase transitions of cosmological interest may be weakly first-order and
cannot be analyzed by a simple perturbative expansion around mean field theory.
We propose a simple two-scalar model--the cubic anisotropy model--as a foil for
theoretical techniques to study such transitions, and we review its
similarities and dissimilarities to the electroweak phase transition in the
early universe. We present numerical Monte Carlo results for various
discontinuities across very weakly first-order transitions in this model and,
as an example, compare them to epsilon-expansion results. For this purpose, we
have computed through next-to-next-to-leading order in epsilon.

categories: hep-ph cond-mat.stat-mech hep-lat hep-th


title:
The gauge boson contributions to the radiatively corrected mass of the
  scalar Higgs boson in the minimal supersymmetric standard model

abstract:
  We derive analytic formulas for the radiatively corrected mass of the scalar
Higgs boson in the framework of the minimal supersymmetric standard model
(MSSM). Since the scalar-top-quark mass in our analysis include terms
proportional to the gauge couplings in the 1-loop effective potential, the
radiatively corrected mass of the scalar Higgs boson partially contains the
gauge boson contributions. At the 1-loop level, the upper bound on the lighter
scalar Higgs boson mass can be increased about 20 GeV in favor of the partial
contributions of the gauge bosons. Thus the improved absolute upper bound on
the lighter scalar Higgs boson mass is about 150 GeV.


title:
On the similarity of the parton distributions in nuclei with more than
  three nucleons

abstract:
  It is shown that the latest results from NMC and E665 on the
$F_2^A(x)/F_2^{D}(x)$ obtained in the shadowing region, bring new evidence of
the universal $A$ -- dependence of distorsions of a free nucleon structure
function by nuclear medium. The universality holds in the entire $x$ -range and
can be explained as a saturation of the distortions of the parton distributions
in a four-nucleon system.


title: Naturalness bounds on gauge mediated soft terms

abstract:
  After a general discussion about the quantitative meaning of the naturalness
upper bounds on the masses of supersymmetric particles, we compute these bounds
in models with gauge-mediated soft terms. We find interesting upper limits on
the right-handed slepton masses that, unless the messenger fields are very
light, disfavor minimal models with large messenger content. Deep unphysical
minima, that however turn out to be not dangerous, are usually present in such
models. The mu-problem can be solved by adding a light singlet only at the
price of a large amount of fine tuning that gives also rise to heavy sparticles
and large tan\beta.


title: How to measure diffraction in two-photon collisions at LEP

abstract:
  The possibility to measure diffraction dissociation in collisions of real and
virtual photons at LEP2 is pointed out.


title: Scattering of soft, cool pions

abstract:
  Consider the effective lagrangian for pions in the chiral limit, computed to
leading order in an expansion about zero temperature. To describe the
scattering of pions with small momenta, it is necessary to include not just the
usual shift in the pion decay constant, but also a new, nonlocal term, which is
precisely analogous to the hard thermal loops of hot gauge theories.


title:
Wavefunction corrections and off-forward gluon distributions in
  diffractive J/psi electroproduction

abstract:
  Diffractive production of J/Psi particles by virtual photons on a proton
target is studied with a view towards understanding two important corrections
to the leading order result. First, the effect of Fermi motion of the heavy
quarks is studied by performing a systematic expansion in the relative
velocity, and a simple correction factor is derived. This is considerably less
than estimated previously. Second, since the kinematics necessarily requires
that non-zero momentum be transferred to the proton, off-forward gluon
distributions are probed by the scattering process. To estimate the importance
of the off-forwardness, we compute, in leading order perturbation theory, the
extent of deviation from the usual forward gluon distribution in a quark.


title: Problems and Prospects in Spin Physics

abstract:
  This talk reviews some of the hot topics in spin physics and related
subjects, including perturbative QCD predictions for polarized parton
distributions and their possible behaviours at small x, the Bjorken and singlet
sum rules and the treatment of higher orders in perturbative QCD, different
interpretations of the EMC spin effect including chiral solitons and the axial
U(1) anomaly, other experimental indications for the presence of strange quarks
in the nucleon wave function, implications for dark matter physics, and a few
words about polarization as a tool in electroweak physics.


title: Radiative Higgs Boson Decays H -> f fbar gamma

abstract:
  Higgs boson radiative decays of the form $H\rightarrow f\bar{f}\gamma$ are
calculated in the Standard Model using the complete one-loop expressions for
the decay amplitudes. Contributions to the radiative width from leptons and
light quarks are given. We also present $e\bar{e}$ invariant mass distributions
for $H\rightarrow e\bar{e}\gamma$, which illustrate the importance of the
photon pole contribution and the effects of the box diagrams.


title:
SU(3) Breaking in Neutral Current Axial Matrix Elements and the Spin
  Content of the Nucleon

abstract:
  We examine the effects of SU(3) breaking in the matrix elements of the
flavour-diagonal axial currents between octet baryon states and find that SU(3)
breaking may be substantial for some matrix elements. We estimate the strange
axial matrix element in the proton to be between -0.35 and 0 and the matrix
element of the flavour-singlet current in the proton to be between -0.1 and
+0.3 from the E-143 measurement g_1(x) . The up-quark content of the $\Xi^-$ is
discussed and its implications for nonleptonic weak processes discussed. We
also estimate the matrix element of the axial current coupling to the $Z^0$
between all octet baryon states. This may be important for neutrino
interactions in dense nuclear environments, where hyperons may play an
important role.


title:
Measurement of the W W gamma and W W Z Couplings in the Process $e^+e^-
  \to l \nu q\bar{q}'$

abstract:
  We studied the sensitivity of the process $e^+e^-\to \ell \nu q\bar{q}'$ to
anomalous trilinear gauge boson couplings of the $WW\gamma$ and WWZ vertices at
the center of mass energies $\sqrt{s}=500$ GeV and 1 TeV. The bounds for the
couplings we obtained result from an analysis of a five dimensional angular
differential cross section. In our calculations we included all tree level
Feynman diagrams contributing to the final state as well as the finite widths
of the vector bosons. Both unpolarized and polarized beams were considered. We
found that the 500 GeV measurements will be at the level of loop contributions
to the couplings and may show hints of new physics while the 1 TeV should be
sensitive to new physics at the loop level. We also explored $\ell\nu q\bar{q}$
final states off the W resonance and found that useful information could be
extracted from this region of phase space.


title: Study on the single-W production at LEP energies

abstract:
  We present a study of single-W production ($\eetoenuW$) as a new probe of the
anomalous couplings at the LEP energy region. The cross-section measurement of
the single-W process is found to give complementary bounds on the anomalous
couplings to those obtained from W-pair analysis at LEP2.


title:
Extraction of parton distributions and $\alpha_s$ from DIS data within
  the Bayesian treatment of systematic errors

abstract:
  We have performed the NLO QCD global fit of BCDMS, NMC, H1 and ZEUS data with
full account of point-to-point correlations using the Bayesian approach to the
treatment of systematic errors. Parton distributions in the proton associated
with experimental uncertainties, including both statistical and systematic ones
were obtained. The gluon distribution in the wide region of $x$ was determined
and it turned out to be softer than in the global analysis using prompt photon
data. We also obtained the robust estimate of $\alpha_s(M_Z) = 0.1146\pm0.0036
(75% C.L.)$ based on Chebyshev's inequality, which is compatible with the
earlier determination of $\alpha_s$ from DIS data, but with less dependence on
high twist effects.


title:
On the Resummation of the $\alpha \ln^2 z Terms for QED Corrections to
  Deep-Inelastic $ep$ Scattering and $e^+e^-$ Annihilation

abstract:
  The resummation of the $\alpha \ln^2(z)$ non-singlet contributions is
performed for initial state QED corrections. As examples, the effect of the
resummation on neutral-current deep-inelastic scattering and the $e^+ e^-
\rightarrow \mu^+ \mu^-$ scattering cross section near the $Z^0$-peak is
investigated.


title:
Resummation of infrared renormalons in the pion electromagnetic form
  factor calculations

abstract:
  The pion electromagnetic form factor F_{\pi}(Q^{2}) is calculated at the
leading order of pQCD using the running coupling constant
(\alpha_{S}(Q^{2}(1-x)(1-y))) approach. The resummed expression for
F_{\pi}(Q^{2}) is found. It is shown that the effect of the infrared
renormalons can be taken into account by scale-setting procedure
$\alpha_{S}(Q^{2}) \rightarrow \alpha_{S}(e^{f(Q^{2})}Q^{2})$ in the leading
order expression


title: Nucleon Spin Distributions From Recent SMC, SLAC and DESY Data

abstract:
  We have extracted polarized nucleon distributions from recent data at CERN,
SLAC and DESY. The flavor-dependent valence and sea quark spin distributions
are determined for each experiment. The up and down distributions are
comparable, but the strange sea contribution determined from different
experiments do not agree, even including higher order corrections. Only
experiments sensitive to the polarized gluon and sea will reconcile these
differences.


title: A Global chi^2 Analysis of Electroweak Data in SO(10) SUSY GUTs

abstract:
  We present the details of a global $\chi^2$ analysis of electroweak data,
including fermion masses and mixing angles, in SO(10) SUSY GUTs. Just as
precision electroweak data is used to test the Standard Model, the well
determined Standard Model parameters are the precision electroweak data for
testing theories beyond the Standard Model. In this paper we use the latest
experimentally measured values for these parameters. We study several models
discussed in the literature. One of these models provides an excellent fit to
the low energy data with $\chi^2 \sim 1$ for 3 degrees of freedom. We present
graphs of constant $\chi^2$ contours as functions of position in soft SUSY
breaking parameter space, as well as our predictions for a few selected points
in parameter space. We also study the sensitivity of our results to changes in
various parameters. Finally, we discuss the consequences of our work in the
context of a general MSSM analysis at the Z scale.


title: Direct J/psi and psi' Polarization and Cross Sections at the Tevatron

abstract:
  Transverse polarization of ${}^3 S_1$ charmonium states, produced directly in
$p\bar{p}$ collisions at asymptotically large transverse momentum p_t, has
emerged as the most prominent test of color octet contributions and spin
symmetry in quarkonium production. We present predictions for the polar angle
distribution at moderate values of p_t \sim 4 - 20 GeV, covered by the Tevatron
Run I data. We update the fits of NRQCD matrix elements and discuss their
theoretical uncertainties. With our best fit values, no transverse polarization
is expected at p_t \sim 5 GeV, but the angular distribution is predicted to
change dramatically as p_t increases to 20 GeV.


title: Local discrete symmetries from superstring derived models

abstract:
  Discrete and global symmetries play an essential role in many extensions of
the Standard Model, for example, to preserve the proton lifetime, to prevent
flavor changing neutral currents, etc. An important question is how can such
symmetries survive in a theory of quantum gravity, like superstring theory. In
a specific string model I illustrate how local discrete symmetries may arise in
string models and play an important role in preventing fast proton decay and
flavor changing neutral currents. The local discrete symmetry arises due to the
breaking of the non--Abelian gauge symmetries by Wilson lines in the
superstring models and forbids, for example dimension five operators which
mediate rapid proton decay, to all orders of nonrenormalizable terms. In the
context of models of unification of the gauge and gravitational interactions,
it is precisely this type of local discrete symmetries that must be found in
order to insure that a given model is not in conflict with experimental
observations.


title: Family Replication in the Dual Standard Model

abstract:
  The family replication problem is addressed in the context of the dual
standard model. The breaking of a simple grand unified group to $[G_{low}
\times H_1 \times H_2 \times H_3]/Z_5^3$ and then further to $G_{low}$,
produces a spectrum of stable monopoles that fall in three families each of
whose magnetic quantum numbers correspond to the electric charges on the
fermions of the Standard Model. Here $G_{low}=[SU(3) \times SU(2) \times
U(1)]/Z_6$ is the symmetry group of the standard model above the weak scale,
and $H_i$ are simple Lie groups which each have a $Z_5$ symmetry in common with
$G_{low}$.


abstract:
  $Q^2$ evolution of structure functions in the nucleon and nuclei is
investigated by using usual DGLAP equations and parton-recombination equations.
Calculated results for proton's $F_2$ and for the ratio $F_2^{Ca}/F_2^D$ are
compared with various experimental data. Furthermore, we study nuclear
dependence of $Q^2$ evolution in tin and carbon nuclei: $\partial
[F_2^{Sn}/F_2^C]/ \partial [ln Q^2]\ne 0$, which was found by NMC.


title: A new view of the 0- and 2+ glueballs

abstract:
  Data on $J/\Psi \to \gamma (\rho\rho)$ demand a broad $0^-$ $\rho\rho$
signal, attributable to a glueball with a mass of 1750--2100 MeV. Decays of
this broad state to $\rho\rho$, $\omega\omega$, $K^*\bar K^*$ and $\phi \phi$
channels agree well with flavour blindness. The narrow $\iota(1440)$ may be
attributed to mixing between the glueball and the $s\bar s$ radial excitation.
The latter is pushed down in mass by repulsion between the two levels. We
conjecture that the $2^+$ glueball may likewise be broad. Mixing between it and
the $2^3P_2~q\bar q$ and $s\bar s$ radial excitation can explain the appearance
of $f_2(1565)$ and a $2^+$ $\Theta (1710)$ at masses lower than anticipated.
Mixing with higher $q\bar q$ states can explain the $2^+$ resonance at 1920 MeV
and also $\phi \phi$ signals observed by Etkin et al. and by the JETSET
collaboration.


title:
Significance of Single Pion Exchange Inelastic Final State Interaction
  for D->VP Processes

abstract:
  We evaluate the contribution of the final state interaction (FSI) due to
single pion exchange inelastic scattering for $D^+\rightarrow \bar
{K}^{0*}\pi^+$ and $D^+\rightarrow \bar K^0\rho^+$ processes. The effects are
found to be very significant. The hadronic matrix elements of the weak
transition are calculated in terms of the heavy quark effective theory (HQET),
so are less model-dependent and more reliable.