title:
$\mbox{SU}(3)_L \otimes \mbox{U}(1)_N$ and $\mbox{SU}(4)_L \otimes
  \mbox{U}(1)_N$ gauge models with right-handed neutrinos

abstract:
  Pisano and Pleitez have introduced an interesting $\mbox{SU}(3)_C \otimes
\mbox{SU}(3)_L \otimes \mbox{U}(1)_N$ gauge model which has the property that
gauge anomaly cancellation requires the number of generations to be a multiple
of 3. We consider generalizing that model to incorporate right-handed
neutrinos. We find that there exists a non-trivial generalization of the
Pisano-Pleitez model with right-handed neutrinos which is actually simpler than
the original model in that symmetry breaking can be achieved with just three
$\mbox{SU}(3)_L$ triplets (rather than 3 $\mbox{SU}(3)_L$ triplets and a
sextet). We also consider a gauge model based on $\mbox{SU}(3)_C\otimes
\mbox{SU}(4)_L \otimes \mbox{U}(1)_N$ symmetry. Both of these new models also
have the feature that the anomalies cancel only when the number of generations
is divisible by 3.


title: A parity invariant $SU(3)_c \otimes SU(3)_L \otimes U(1)$ model

abstract:
  We examine a $SU(3)_c \otimes SU(3)_{L}\otimes U(1)$ gauge model which has a
parity symmetric Lagrangian. The parity symmetry has the novel feature that it
interchanges the gluons with the $SU(3)_L$ gauge bosons (which contain the
ordinary $SU(2)_L$ weak gauge bosons). We show that the model reduces to the
standard model at low energies and also predicts new physics in the form of
exotic fermions.


title: Chiral Current at High Temperatures

abstract:
  The BP-FTW effective action is a good laboratory to study the nature of
chiral symmetry at high $T$. It is invariant under a new Noether charge,
$\Qbeta$. By explicit quantization, performed to order $\Tprime$ we show that
the thermal vacuum is annihilated by $\Qbeta$, so that the new chiral symmetry
is not broken spontaneously at high $T$. This high $T$ Noether charge is,
however, different from the usual zero temperature chirality, $\Q$. Our
quantization also shows that the thermal vacuum is not annihilated by $\Q$, so
that the old chiral symmetry remains broken at high $T$. The thermal vacuum is
thus every bit as `structured' and `complex' as the Nambu-Jona-Lasinio vacuum
at zero temperature. We exhibit the relation between the normal mode expansion
for $\Qbeta$ versus the usual expansion for $\Q$. In an appendix, we point out
the analyticity properties of the fermion propagator in real time formalism,
and verify the canonical nature of the thermal Green function.


title: Light Gluinos and the Longitudinal Structure Function

abstract:
  The leading effect of light gluinos on the deep inelastic longitudinal
structure function is calculated. We present the explicit analitic expression
for the Wilson coefficient. After convolution with quark, gluon and gluino
distributions we found that the size of the contribution is of order a few
percent of the total $F_L$. Some phenomenological implications for HERA and
LEP/LHC are given.


title:
General Solutions for Tunneling of Scalar Fields with Quartic Potentials
  in de Sitter Space

abstract:
  The tunneling rates for scalar fields with quartic potentials in de Sitter
space in the limit of no gravitational back reaction are calculated numerically
and the results are fitted by analytic formulae.


title: Dispersion Relations and the Nucleon Polarizability

abstract:
  Recent experimental results on the proton and neutron polarizabilities are
examined from the point of view of backward dispersion relations. Results are
found to be in reasonable agreement with the measured values. A rigorous
relationship between the nucleon and pion polarizabilities is derived and shown
to be in excellent agreement with several models.


title:
Model Independent Extraction of $|V_{\rm bc}|$ Without Heavy Quark
  Symmetry

abstract:
  A new method to extract $|V_{\rm bc}|$ is proposed based on a sum--rule for
semileptonic decays of the $B$ meson. The method relies on much weaker
assumptions than previous approaches which are based on heavy--quark symmetry.
This sum--rule only relies on the assumption that the virtual $c \overline{c}$
pair content of the $B$ meson can be neglected. The extraction of the CKM
matrix element also requires that the sum--rule saturates in the kinematically
accessible region.


title: Note on Strange Quarks in the Nucleon

abstract:
  Scalar matrix elements involving strange quarks are studied in several
models. Apart from a critical reexamination of results obtained in the Nambu
and Jona-Lasinio model we study a scenario, motivated by instanton physics,
where spontaneous chiral symmetry breaking is induced by the flavor-mixing 't
Hooft interaction only. We also investigate possible contributions of virtual
kaon loops to the strangeness content of the nucleon.


title: Outcome from Spontaneous CP Violation for B Decays

abstract:
  In the aspon model solution of the strong $CP$ problem, there is a gauged
$U(1)$ symmetry, spontaneously broken by the same vacuum expectation value
which breaks $CP$, whose massive gauge boson provides an additional mechanism
of weak $CP$ violation. We calculate the $CP$ asymmetries in $B$ decays for the
aspon model and show that they are typically smaller than those predicted from
the standard model. A linear relation between the $CP$ asymmetries of different
decay processes is obtained.


title: Electroweak Baryogenesis: A Status Report

abstract:
  There are many reasons to believe that there might be new sources of
CP-violation beyond the phases of the KM matrix. One of these is the
possibility of electroweak baryogenesis. We describe some recent developments
in this subject and make some comments on the possibility that the minimal
standard model might itself be the origin of the baryon asymmetry. To appear in
the Proceedings of the Third KEK Topical Conference on CP Violation, its
Implications to Particle Physics and Cosmology, 16--18 November, 1993.


title: Electroweak Symmetry Breaking and Bottom-Top Yukawa Unification

abstract:
  The condition of unification of gauge couplings in the minimal supersymmetric
standard model provides successful predictions for the weak mixing angle as a
function of the strong gauge coupling and the supersymmetric threshold scale.
In addition, in some scenarios, e.g.\ in the minimal SO(10) model, the tau
lepton and the bottom and top quark Yukawa couplings unify at the grand
unification scale. The condition of Yukawa unification leads naturally to large
values of $\tan\beta$, implying a proper top quark--bottom quark mass
hierarchy. In this work, we investigate the feasibility of unification of the
Yukawa couplings, in the framework of the minimal supersymmetric standard model
with (assumed) universal mass parameters at the unification scale and with
radiative breaking of the electroweak symmetry. We show that strong
correlations between the parameters $\mu_0$ and $M_{1/2}$ appear within this
scheme. These correlations have relevant implications for the sparticle
spectrum, which presents several characteristic features. In addition, we show
that due to large corrections to the running bottom quark mass induced through
the supersymmetry breaking sector of the theory, the predicted top quark mass
and $\tan\beta$ values are significantly lower than those previously estimated
in the literature.


title: Probing Symmetry-Breaking Pattern Using Sfermion Masses

abstract:
  We study the mass spectrum of superparticles within supersymmetric grand
unified models. For gaugino masses, it is pointed out that the GUT-relation in
the $SU(5)$ model is applicable to a more general case where a grand-unified
gauge group breaks down to the standard model gauge group by several steps. We
also show that the mass spectrum of squarks and sleptons carries the
information on the breaking pattern of the gauge symmetry. It is demonstrated
in some $SO(10)$ models how the scalar mass spectrum distinguishes various
$SO(10)$ breaking patterns from each other.


title: Looking up at the GUT/Planck World

abstract:
  The importance of the mass spectroscopy of the superparticles is emphasized.
It will be shown that the gauge coupling constants give us information on the
GUT-scale mass spectrum once the superparticle masses are known. The gaugino
masses will provide us a model-independent test of the grand unification
irrespective of the symmetry breaking pattern. The sfermion masses carry the
information on the intermediate symmetries, if present. Combining the mass
spectrum, we will be able to distinguish among the GUT models, and hopefully
supergravity models also.


title: Pair Production in the Quantum Boltzmann Equation

abstract:
  A source term in the quantum Boltzmann equation, which accounts for the
spontaneous creation of $e^+e^-$-pairs in external electric fields, is derived
from first principles and evaluated numerically. Careful analysis of time
scales reveals that this source term is generally non-Markovian. This implies
in particular that there may be temporary violations of the $H$-theorem.


title: A Note in the Skyrme Model with Higher Derivative Terms

abstract:
  Another stabilizer term is used in the classical Hamiltonian of the Skyrme
Model that permits in a much simple way the generalization of the higher-order
terms in the pion derivative field. Improved numerical results are obtained.


title:
High-Energy Vector-Boson Scattering with Non-Standard Interactions and
  the Role of a Scalar Sector

abstract:
  The high-energy behavior of vector-boson scattering amplitudes is examined
within an effective theory for non-standard self-interactions of electroweak
vector-bosons. Irrespectively of whether this theory is brought into a gauge
invariant form by including non-standard interactions of a Higgs particle I
find that terms that grow particularly strongly with increasing scattering
energy are absent. Different theories are compared concerning their high-energy
behavior and the appearance of divergences at the one-loop level.


title: Phenomenological Consequences of Singlet Neutrinos

abstract:
  In this paper, we study the phenomenology of right-handed neutrino
isosinglets. We consider the general situation where the neutrino masses are
not necessarily given by $m_D^2/M$, where $m_D$ and $M$ are the Dirac and
Majorana mass terms respectively. The consequent mixing between the light and
heavy neutrinos is then not suppressed, and we treat it as an independent
parameter in the analysis. It turns out that $\mu-e$ conversion is an important
experiment in placing limits on the heavy mass scale ($M$) and the mixing.
Mixings among light neutrinos are constrained by neutrinoless double beta
decay, as well as by solar and atmospheric neutrino experiments. Detailed
one-loop calculations for lepton number violating vertices are provided.


title: Improved Theory of the Muonium Hyperfine Structure

abstract:
  Terms contributing to the hyperfine structure of the muonium ground state at
the level of few tenths of kHz have been evaluated. The $\alpha^2 (Z\alpha)$
radiative correction has been calculated numerically to the precision of 0.02
kHz. Leading $\ln (Z\alpha )$ terms of order $\alpha^{4-n} (Z\alpha)^n ,
n=1,2,3,$ and some relativistic corrections have been evaluated analytically.
The theoretical uncertainty is now reduced to 0.17 kHz. At present, however, it
is not possible to test QED to this precision because of the 1.34 kHz
uncertainty due to the muon mass.


title:
$\epsilon^\prime/\epsilon$: theoretical results and updated
  phenomenological analysis

abstract:
  We present the results for the Next-to-Leading Order effective hamiltonian
for $\Delta S\!=\! 1$ decays, in presence of both QCD and QED corrections, and
update the existing theoretical predictions for $\epsilon^\prime/\epsilon$. To
appear on the Proceedings of the Third KEK Topical Conference on CP Violation,
its Implications to Particle Physics and Cosmology, Tsukuba, 16-18 November
1993


title: Standard Model Decays of Tau into Three Charged Leptons

abstract:
  Analytic expressions are given for the $\tau$ decays into three charged
leptons, $\tau\rta \ell\ell\overline \ell\nu_\tau\overline \nu_\ell$, where the
$\ell$ are combinations of electrons and muons, and for the radiative decays
$\tau\rta \gamma\ell\nu_\tau\overline \nu_\ell$. The branching ratios are
sensitive functions of whether the final state $\ell$ are muons or electrons.


title:
Semiclassical Decay of Excited String States on Leading Regge
  Trajectories

abstract:
  We study the decay of hadrons based on a semiclassical string model. By
including quark mass effects we find that the width to mass ratio $\G/m$ is an
increasing function of $m$, which increases most rapidly for massive quarks.
This is consistent with the available data. The decay probability of hadrons on
the leading Regge trajectories is computed taking the effect of the string
rotation into account. The resulting decay probability is no longer uniform
along the length of the string but varies in a manner that is in qualitative
agreement with the available data. We argue in favour of possible experiments
that would test our predictions more accurately and help open a window to the
nonperturbative aspects of QCD.


title:
Next-to-leading Order Parton Model Calculations in the Massless
  Schwinger Model

abstract:
  We carry out next-to-leading order (NLO) parton model calculations for the
standard hard ``QCD'' processes in the massless Schwinger model. The asymptotic
expansion of the exact result for the deep inelastic cross section is used to
infer the NLO distribution function. These distribution functions are then used
to calculate the NLO Drell-Yan parton model cross section and it is found to
agree with the corresponding term in the expansion of the exact result for the
Drell-Yan cross section. Finally, by using the bosonization formula and the
exact solutions we study the interference between different partonic processes.


title: Detecting Higgs Boson Decay to Neutralinos at Hadron Supercolliders

abstract:
  We examine prospects for detecting the neutral Higgs bosons of minimal
supersymmetric models (MSSM) when their decays into neutralino pairs are
kinematically allowed. The best signature appears to be
$H_h,H_p\to\tz_2\tz_2\to 4\ell +\eslt$. We argue that Standard Model
contributions to this signature are negligible, and examine regions of MSSM
parameter space where the four lepton mode should be observable at the Large
Hadron Collider. The same signal can also come from continuum neutralino pair
production. We propose a set of cuts to illustrate that the neutralino decay
mode of the Higgs bosons provides a viable signal over a substantial range of
model parameters, and show that it may be separable from continuum neutralino
production if sufficient integrated luminosity can be accumulated.


title:
Grand Unified Theories and Supersymmetry in Particle Physics and
  Cosmology

abstract:
  A review is given on the consistency checks of GUT, which unify the
electroweak and strong nuclear forces into a single theory. Such theories
predict a new kind of force, which could provide answers to several open
questions in cosmology. The possible role of such a ``primeval'' force will be
discussed in the framework of the Big Bang Theory. Although such a force cannot
be observed directly, there are several predictions of GUT's, which can be
verified at low energies. The MSSM distinguishes itself from other GUT's by a
successful prediction of many unrelated phenomena with a minimum number of
parameters. Among them: a) Unification of the couplings constants; b)
Unification of the masses; c) Existence of dark matter; d) Proton decay; e)
electroweak symmetry breaking at a scale far below the unification scale. A
combined fit shows that indeed the MSSM model can satisfy all these constraints
simultaneously. The corresponding constraints on the as yet unknown top mass,
the strong coupling constant, and all SUSY masses are given within the minimal
model, taking into account the complete second order RGE's for the couplings
and the one-loop corrected Higgs potential for the calculation of the Z and the
Higgs masses.


title: Nucleon Distribution Amplitudes and Observables

abstract:
  Invited talk presented at the International Workshop on Hadron Structure '93,
Bansk\'a \v Stiavnica, Slovakia, 5-10 September, 1993; to be published in the
Proceedings.


title:
Exploring the Yukawa Unified Minimal Supergravity Model at the Tevatron,
  LEP-II, and the LHC

abstract:
  We explore the prospects for detection of sparticles and Higgs bosons at the
Tevatron, LEP-200 and the LHC in the allowed parameter space of a `yukawa
unified' ($\lambda_b(M_U)=\lambda_{\tau}(M_U)$) minimal supergravity (YUMS)
model, where the only non-zero unification scale soft-SUSY-breaking terms are a
universal gaugino mass and a Higgs mixing term. In a bottom-up approach, just
two weak scale parameters, $\tanb$ and $\mha$, (along with the sign of the
Higgs mixing parameter $\mu$) completely parameterize the model. Many
interesting `special' situations regarding sparticle and Higgs discovery arise,
such as the importance of the invisible $\hl\rta\cnone\cnone,\snu\snubar$ decay
modes.


title: B Decays - Measurements and Predictions

abstract:
  Hadronic decays of $B$ mesons are reviewed. First, masses of $B$ mesons and
observed patterns together with physics behind them are discussed. Then the
effective Hamiltonian responsible for major decays is presented and its
practical applications are discussed in the context of factorization. Various
tests of factorization are then studied. For rare decays, the focus is placed
on $K\pi$, $\pi\pi$ final state and the penguin-mediated $X_s\gamma$. In
general, the measurements are in excellent agreement with predictions of the
standard model.


title: Soft contribution to the pion form factor from light-cone QCD sum rules

abstract:
  We propose a simple method to calculate the pion form factor at not very
large momentum transfers, which combines the technique of the QCD sum rules
with the description of the pion in terms of the set of wave functions of
increasing twist. This approach allows one to calculate the soft (end point)
contribution to the form factor in a largely model-independent way. Our results
confirm existing expectations that the soft contribution remains important at
least up to the momentum transfers of order 10 GeV$^2$, and suggest that it
comes from the region of relatively small transverse separations of order 1
GeV$^{-1}$.


title: Solar Neutrino Oscillations

abstract:
  Invited review talk at the International Conference on Non-Accelerator
Particle Physics (ICNAPP-94), Bangalore, India, 2-9 January 1994. Latex file.


title: On Proton and Delta Wave Functions

abstract:
  Physical wave functions for the nucleon and the $\Delta^{+}$ isobar are
presented, which unify the best features of previous models. With these wave
functions we can calculate elastic form factors and the decays of the
charmonium levels ${}^{3}S_{1}$, ${}^{3}P_{1}$, ${}^{3}P_{2}$ into $p\bar p$ in
agreement with the data. A striking scaling behavior between
$R=|G_{\text{M}}^{\text{n}}|/G_{\text{M}}^{\text{p}}$ and the coefficient
$B_{4}$ of the Appell polynomial decomposition of the nucleon distribution
amplitude is found; the implications for elastic nucleon cross sections are
discussed.


title: Neutrino Properties in a GUT Analysis for Fermion Masses

abstract:
  In practically all extentions of the standard model, the neutrinos naturally
acquire a mass. The neutrino mass matrix, however, contains many parameters
which can neither be predicted by the prevailing models nor can be fitted to
the data. We propose a fermion mass matrix ansatz in the context of Grand
Unified Supersymmetric Theories (GUTs) at the GUT scale and use the
renormalization group equations for the gauge and Yukawa couplings to predict
the 13 arbitrary parameters of the Standard model. The constraints imposed by
the charged fermion data are used to make predictions in the neutrino sector.
The neutrino mass matrix is worked out in the case of the flipped SU(5) model
and the predictions are compared with the available experimental data.


title: Dynamics of a Disoriented Chiral Condensate

abstract:
  We use the linear $\sigma$ model to analyse the dynamics of a disoriented
chiral condensate. For idealized boundary conditions appropriate to high energy
collisions, the problem can be reduced to a one dimensional one. The evolution
of the chiral state is then that of a simple dynamical system and can be
studied analytically.


title: Closing the Universe by relaxing the cosmological constant

abstract:
  We propose a string-inspired model which correlates several aspects of
particle physics and cosmology. Inspired by the flat directions and the absence
of adjoint Higgs representations found in typical string models, we consider a
no-scale $SU(5)\times U(1)$ supergravity model. This model entails well
determined low-energy phenomenology, such as the value of the neutralino dark
matter relic abundance and a negative contribution to the vacuum energy. A
positive contribution to the vacuum energy is also typically present in string
theory as a consequence of the running of the fundamental constants towards
their fixed point values. If these two contributions cancel appropriately, one
may end up with a vacuum energy which brings many cosmological observations
into better agreement with theoretical expectations. The present abundance of
neutralinos would then be fixed. We delineate the regions of parameter space
allowed in this scenario, and study the ensuing predictions for the sparticle
and Higgs-boson masses in this model.


title:
The 16\half-N_f Expansion and the Infrared Fixed Point in Perturbative
  QCD

abstract:
  In QCD with 16\half-epsilon massless quark flavours there is an infrared
fixed point with alpha_s/pi = (8/321)epsilon in the limit epsilon -> 0+. I
develop the idea of Banks and Zaks to expand about N_f=16\half. This expansion
is certainly useful for N_f=16, 15, 14, ..., and arguably it can reach the
phenomenologically interesting case N_f=2, where it suggests that alpha_s/pi
"freezes" to a value of order of magnitude 0.4 in the infrared.


title: Meson Structure in Deep Inelastic Scattering

abstract:
  We study the deep inelastic structure functions of mesons within the Nambu
and Jona-Lasinio model. We calculate the valence quark distributions in $\pi $,
$K $, and $\rho $ mesons at the low energy model scale, which are evoluted to
the experimental momentum scale in terms of the Altarelli-Parisi equation. The
resulting distribution functions show reasonable agreements with experiment. We
also discuss the semi-inclusive lepton nucleon scattering process with a slow
nucleon in coincidence in the final state, which reveals the off-shell
structure of the pion.


title:
Neutral Scalar Higgs Masses and Production Cross Sections in an Extended
  Supersymmetric Standard Model

abstract:
  Upper bounds on the three neutral scalar Higgs masses are considered in the
supersymmetric standard model with a gauge singlet Higgs field. When the
lightest Higgs is singlet-dominated the second lightest Higgs is shown to lie
near or below the theoretical upper bound on the lightest Higgs mass. We also
consider detectability of these Higgs bosons at a future $e^+ e^-$ linear
collider with $\sqrt{s}\sim 300 $ GeV and show that at least one of the neutral
scalar Higgs has a production cross section larger than 0.04~pb.


title:
Isgur - Wise Functions for Confined Light Quarks in a Colour Electric
  Potential

abstract:
  We explore the influence on the Isgur-Wise function of the colour electric
potential between heavy and light quarks in mesons. It is shown that in bag
models, its inclusion tends to restore light quark flavour symmetry relative to
the MIT bag predictions, and that relative to this model it flattens the
Isgur-Wise function. Results compare very well with observations.


title: The Pion Form Factor. Where Does It Come From?

abstract:
  We discuss the nonleading, ``soft" contribution to the pion form factor at
intermediate momentum transfer within operator product expansion approach. We
argue, that the corresponding contribution can temporarily {\bf simulate} the
leading twist behavior in the extent region of $ Q^2:~~3 GeV^2\leq Q^2\leq 35
GeV^2 $, where $Q^2 F(Q^2)\sim const.$
  Such a mechanism, if it is correct, would be an explanation of the
phenomenological success of the dimensional counting rules (which theoretically
correspond to the keeping of the asymptotically leading terms only) at
available, very modest $Q^2$. The relation with quark model calculation is also
discussed.


title:
Contribution of the elastic radiative tail to the deep inelastic muon
  scattering on heavy targets

abstract:
  Improvement of the radiative correction scheme for the deep inelastic
scattering on the heavy targets is discussed. Arguments that the contribution
of the radiative tail from the elastic peak should be calculated without use of
the Born approximation in the case of the heavy target scattering are
presented. The semianalytical approach based on the classical solution of the
old bremsstrahlung problem is shortly described. The numerical results for the
new correction factor are presented for the scattering on tin and lead.


title: Rapidity Correlations in $W\gamma$ Production at Hadron Colliders

abstract:
  We study the correlation of photon and charged lepton pseudorapidities,
$\eta(\gamma)$ and $\eta(\ell)$, $\ell=e,\,\mu$, in $p\,\pbar \rightarrow
W^\pm\gamma+X\rightarrow \ell^\pm p\llap/_T\gamma+X$. In the Standard Model,
the $\Delta\eta(\gamma,\ell)= \eta(\gamma) - \eta(\ell)$ differential cross
section is found to exhibit a pronounced dip at $\Delta\eta(\gamma,\ell)
\approx \mp 0.3$ ($=0$)in $p\bar p$ ($pp$) collisions, which originates from
the radiation zero present in $q\bar q'\rightarrow W\gamma$. The sensitivity of
the $\Delta\eta(\gamma,\ell)$ distribution to higher order QCD corrections,
non-standard $WW\gamma$ couplings, the $W+$~jet ``fake'' background and the
cuts imposed is explored. At hadron supercolliders, next-to-leading order QCD
corrections are found to considerably obscure the radiation zero. The
advantages of the $\Delta\eta(\gamma,\ell)$ distribution over other quantities
which are sensitive to the radiation zero are discussed. We conclude that
photon lepton rapidity correlations at the Tevatron offer a {\it unique}
opportunity to search for the Standard Model radiation zero in hadronic
$W\gamma$ production.


title: Diffractive Leptoproduction of Vector Mesons in QCD

abstract:
  We demonstrate that the distinctive features of the forward differential
cross section of diffractive leptoproduction of a vector meson can be
legitimately calculated in perturbative QCD in terms of the light-cone $q \bar
q$ wave function of the vector meson and the gluon distribution of the target.
In particular, we calculate the $Q^2$ and nuclear dependence of the diffractive
leptoproduction of vector mesons and estimate the cross section. The production
of longitudinally polarized vector mesons by longitudinally polarized virtual
photons is predicted to be the dominant component, yielding a cross section
behaving as $Q^{-6}$. The nuclear dependence of the diffractive cross sections,
which follows from a factorization theorem in perturbative QCD, provides
important tests of color transparency as well as constraints on the shadowing
of the gluon structure functions and the longitudinal structure functions of
nuclei.


title: Supersymmetric Models With Tan(beta) Close to Unity

abstract:
  Within the framework of supersymmetric grand unification, estimates of the
$b$ quark mass based on the asymptotic relation $m_b \simeq m_\tau$ single out
the region with $\tan\beta$ close to unity, particularly if $m_t(m_t)
\stackrel{_<}{_\sim} 170\ GeV$. We explore the radiative breaking of the
electroweak symmetry and the associated sparticle and higgs spectroscopy in
models with $1 < \tan\beta \stackrel{_<}{_\sim} 1.6$. The lightest scalar higgs
is expected to have a mass below $100\ GeV$, while the remaining four higgs
masses exceed $300\ GeV$. The lower bounds on some of the sparticle masses are
within the range of LEP 200.


title: Analysis of the Pion Wave Function in Light-Cone Formalism

abstract:
  Several general constraints are suggested to analyze the pionic valence-state
wave function. It is found that the present model wave functions used in
light-cone formalism of perturbative quantum chromodynamics have failed these
requirements to fit the pionic form factor data and the reasonable
valence-state structure function which does not exceed the pionic structure
function data for $x \rightarrow 1$ simultaneously. Furthermore, it is pointed
out that there is a possibility to find model wave functions which can satisfy
all of general constraints. Also we show that there are two higher helicity
$(\lambda_{1} + \lambda_{2} =\pm1)$ components in the light-cone wave function
for the pion as a natural consequence from the Melosh rotation and it is
speculated that these components should be incorporated into the perturbative
quantum chromodynamics.


title: Pion Structure Function in the Nambu and Jona-Lasinio model

abstract:
  The pion structure function is studied in the Nambu and Jona-Lasinio (NJL)
model. We calculate the forward scattering amplitude of a virtual photon from a
pion target in the Bjorken limit, and obtain valence quark distributions of the
pion at the low energy hadronic scale, where the NJL model is supposed to work.
The calculated distribution functions are evolved to the experimental momentum
scale using the Altarelli-Parisi equation. The resulting distributions are in a
reasonable agreement with experiment. We calculate also the kaon structure
function and compare the ratio of kaon to pion valence u-quark distributions
with experiment.


title:
Two-loop Correction to the Instanton Density for the Double Well
  Potential

abstract:
  Feynman diagrams in the instanton background are used for the calculation of
the tunneling amplitude, up to the two-loops order. Some mistakes made in the
previous works are corrected. The same method is applied to the next-order
corrections to the ground state wave function.


title:
Resummation of Nonperturbative Corrections to the Lepton Spectrum in
  Inclusive $B\to X\,\ell\,\bar\nu$ Decays

abstract:
  We apply the operator product expansion to resum the leading nonperturbative
corrections to the endpoint region of the lepton spectrum in inclusive
semileptonic $B\to X_q\,\ell\,\bar\nu$ decays, taking into account a finite
quark mass $m_q$ in the final state. We show that both for $b\to c$ and $b\to
u$ transitions, it is consistent to describe these effects by a convolution of
the parton model spectrum with a fundamental light-cone structure function. The
moments of this function are proportional to forward matrix elements of
higher-dimension operators. The prospects for an extraction of the structure
function from a measurement of the lepton spectrum are discussed.


title:
Predictive fermion mass matrix ansatzes in non-supersymmetric SO(10)
  grand unification

abstract:
  We investigate the status of predictive fermion mass ansatzes which make use
of the grand unification scale conditions $m_e=m_d/3$, $m_\mu =3m_s$, and $\mid
V_{cb}\mid =\sqrt{m_{c}/m_{t}}$ in non-supersymmetric SO(10) grand unification.
The gauge symmetry below an intermediate symmetry breaking scale $M_I$ is
assumed to be that of the standard model with either one Higgs doublet or two
Higgs doublets . We find in both cases that a maximum of 5 standard model
parameters may be predicted within $1\sigma$ experimental ranges. We find that
the standard model scenario predicts the low energy $\mid V_{cb}\mid$ to be in
a range which includes its experimental mid-value 0.044 and which for a large
top mass can extend to lower values than the range resulting in the
supersymmetric case. In the two Higgs standard model case, we identify the
regions of parameter space for which unification of the bottom quark and tau
lepton Yukawa couplings is possible at grand unification scale. In fact, we
find that unification of the top, bottom and tau Yukawa couplings is possible
with the running b-quark mass within the $1\sigma$ preferred range $m_b=4.25\pm
0.1\, GeV$ provided $\alpha_{3c}(M_Z)$ is near the low end of its allowed
range. In this case, one may make 6 predictions which include $\mid V_{cb}\mid$
within its $90\%$ confidence limits. However unless the running mass $m_b>4.4\,
GeV$, third generation Yukawa coupling unification requires the top mass to be
greater than


title: The zero-momentum limit of thermal green functions

abstract:
  The zero momentum limit of thermal self-energies calculated in perturbation
theory depends on the order in which the time and the space components of the
momentum are taken to zero. We show that this is an artifact of the
perturbative calculation, and in fact the limit is well-defined when higher
orders of the perturbation expansion are properly taken into account.


title: Natural Gauge Hierarchy in SO(10)

abstract:
  It is shown that a natural gauge hierarchy and doublet-triplet splitting can
be achieved in SO(10) using the Dimopoulos-Wilczek mechanism. Artificial
cancellations (fine-tuning) and arbitrary forms of the superpotential are
avoided, the superpotential being the most general compatible with a symmetry.
It is shown by example that the Dimopoulos-Wilczek mechanism can be protected
against the effects of higher-dimension operators possibly induced by
Planck-scale physics. Natural implementation of the mechanism leads to an
automatic Peccei-Quinn symmetry. The same local symmetries that would protect
the gauge hierarchy against Planck-scale effects tend to protect the axion
also. It is shown how realistic quark and lepton masses might arise in this
framework. It is also argued that ``weak suppression'' of proton decay can be
implemented more economically than can ``strong suppression'', offering some
grounds to hope (in the context of SO(10)) that proton decay could be seen at
Superkamiokande.


title: The Constitutent Quark as a Topological Soliton

abstract:
  Recently it was proposed that the constituent quark is a topological soliton.
I investigate this soliton, calculating its mass, radius, magnetic moment,
color magnetic moment, and spin structure function. Within the approximations
used, the magnetic moments and spin structure function cannot simultaneously be
made to agree with the constituent quark model. Some discussion of what to
expect from better approximations is included.


title: Inconsistency of QED in the Presence of Dirac Monopoles

abstract:
  A precise formulation of $U(1)$ local gauge invariance in QED is presented,
which clearly shows that the gauge coupling associated with the unphysical
longitudinal photon field is non-observable and actually has an arbitrary
value. We then re-examine the Dirac quantization condition and find that its
derivation involves solely the unphysical longitudinal coupling. Hence an
inconsistency inevitably arises in the presence of Dirac monopoles and this can
be considered as a theoretical evidence against their existence. An
alternative, independent proof of this conclusion is also presented.


title:
Neutrino Mass Effects in a Minimally Extended Supersymmetric Standard
  Model

abstract:
  We consider an extension of the supersymmetric standard model which includes
singlet Higgs superfield representations (in three generations) to generate
neutrino masses via the see-saw mechanism. The resulting theory may then
exhibit R-parity violation in the couplings of the singlets, inducing
$R$-parity violating effective interactions among the standard model
superfields, as well as inducing decay of the lightest neutralino, which
otherwise would compose a stable LSP. We compute the rates for the resulting
neutralino decays, depending on the particular superpotential couplings
responsible for the violation of R-parity. We compare to astrophysical
constraints on the decay of massive particles.


title: Ferromagnetic Vacuum and Galactic Magnetic Fields

abstract:
  Non-abelian gauge theories may have a ferromagnet-like vacuum with a non-zero
magnetic field, which also exists at finite temperature. We argue that the
formation of the ferromagnet-like vacuum at GUT scales gives rise to a Maxwell
magnetic field imprinted on the comoving plasma, and that it is energetically
favourable to align the field in different correlation volumes. This results in
a coherent magnetic field pertaining the whole universe, with a magnitude
$B_{now}\simeq 10^{-14}\G$, which is of the correct size to serve as the seed
field for the galactic dynamo.


title:
Fermion Modes in Instanton-Anti-Instanton Background in
  (1+0)-dimensional Model

abstract:
  We evaluate the eigenvalues of Dirac operator in the background of
instanton-anti-instanton configuration (I-$\bar{{\rm I}}$), in a simple
(1+0)-dimensional model, and find that quasi-zero-mode disappears for the
closely localized I-$\bar{{\rm I}}$ configurations. This result suggests that
the configurations which are dominant at high energy in the valley method are
actually non-anomalous ones and irrelevant to fermion number violation. Hence,
there seems to be no theoretical basis for expecting anomalous cross section to
become observable at energies of 10 Tev region in Weinberg-Salam theory.


title: Atmospheric Neutrinos

abstract:
  Recent results of atmospheric neutrino experiments are reviewed and their
possible interpretations are discussed, main emphasis being put on the neutrino
oscillation hypothesis.


title: WWF: a generator for e+e- to 4 fermions + gamma

abstract:
  We present an efficient generator for the process e+e- to 4 fermions + gamma
through off-shell W pairs. It is based on a massless matrix element with
leading order(m^2) corrections. Only the resonant WW graphs are included. We
have tested it against a matrix element without these approximations and found
agreement to within ~1% at LEPII energies.


title: Status of the superworld: from theory to experiment

abstract:
  Review to appear in Progress in Particle and Nuclear Physics. Contents:
{1}Introduction}{1} {2}High precision LEP data and convergence of couplings:
physics is not Euclidean geometry}{2} {3}Interconnections between the measured
quantities due to Unification}{7} {4}The origin of $M_{SUSY}$ and why it should
be abandoned: masses and spectra are needed}{13} {5}The new step forward:
Supergravity}{21} {6}The SU(5) Supergravity Model}{22} {7}SU(5)xU(1)
Supergravity}{32} {8}Detailed calculations for the Tevatron}{47} {9}Detailed
calculations for LEP}{48} {10}Detailed calculations for HERA}{53} {11}Detailed
calculations for Underground Labs and Underwater facilities}{55} {12}Detailed
calculations for indirect experimental detection}{65} {13}The problem of mass
and $m_t$}{73} {14}Conclusions}{77}


title: The Mass of the Dilaton

abstract:
  It is shown that, in a theory where the dilaton is coupled to a Yang-Mills
gauge field which enters a confining phase at scale \Lambda, the dilaton may
grow a mass $m_{dilaton}\sim \Lambda^2/m_{Pl}\sim (m_{SUSY}^2 m_{Pl})^{1/3}\sim
10^8\ \mbox{GeV}. $ This allows ample time for decay before the electroweak era
if $m_{SUSY}\simeq 1\ \mbox{TeV},$ and circumvents cosmological problems
normally associated with its existence.


title: Inconsistency of QED in the Presence of Dirac Monopoles II

abstract:
  We enlarge the local gauge invariance of QED from $~U(1)_A~$ to $~U(1)_A
\times U(1)_{\Theta}~$ by introducing another unphysical pure gauge field
$~\Theta~$ with an independent, unphysical gauge coupling $~\tilde{e}~$. This
pure gauge field can be gauge-transformed away and the resulting theory is {\it
identical to} standard QED. We then re-examine the Dirac quantization condition
(DQC) for point monopoles and find that two essentially different DQCs can be
derived. One DQC involves a gauge coupling $~e~$ in the $~U(1)_A~$ group and
the other only the unphysical gauge coupling $~\tilde{e}~$ in the
$~U(1)_{\Theta}~$ group. The unique physically consistent solution of these two
DQCs is a vanishing magnetic charge, which implies that no Dirac monopole
exists in nature.


title:
$\gamma \gamma$ Production of Non--Strongly Interacting SUSY Particles
  at Hadron Colliders

abstract:
  Non--strongly interacting supersymmetric particles -- sleptons, charginos,
neutral\-inos, and charged Higgs bosons -- are difficult to detect at the Large
Hadron Collider. We therefore examine the possibility of producing particles of
this type in virtual $\gamma \gamma$ collisions at the LHC. Since photons can
be emitted from protons which do not break up in the radiation process, very
clean events can be generated, compensating to some extent for the small event
numbers. Higher rates are expected, at the expense of stray hadrons, for events
in which one or two protons break up.


title: Quark Fragmentation Functions in Low-Energy Chiral Theory

abstract:
  We examine the physics content of fragmentation functions for inclusive
hadron production in a quark jet and argue that it can be calculated in low
energy effective theories. As an example, we present a calculation of $u$-quark
fragmentation to $\pi^+$ and $\pi^-$ mesons in the lowest order in the chiral
quark model. The comparison between our result and experimental data is
encouraging.


title:
An $\alpha^{2}(Z \alpha)^{5}m$ Contribution to the Hydrogen Lamb Shift
  from Virtual Light by Light Scattering

abstract:
  The radiative correction to the Lamb shift of order $\alpha^{2}(Z\alpha)^5m$
induced by the light by light scattering insertion in external photons is
obtained. The new contribution turns out to be equal to
$-0.122(2)\alpha^2(Z\alpha)^5/(\pi n^3)(m_r/m)^3m$. Combining this contribution
with our previous results we obtain the complete correction of order
$\alpha^{2}(Z\alpha)^5m$ induced by all diagrams with closed electron loops.
This correction is $37.3(1)$ kHz and $4.67(1)$ kHz for the $1S$- and
$2S$-states in hydrogen, respectively.


title: Information and Discrimination from b Quark Production on Z Resonance

abstract:
  We introduce and define operatively in a model independent way a new ``heavy"
b-vertexparameter, $\eta_b$, that can be derived from the measurement of a
special polarization asymmetry for production of b-quarks on Z resonance. We
show that the combination of the measurement of $\eta_b$ with that of a second
and previously defined ``heavy" b-vertex parameter $\delta_{bV}$ can
discriminate a number of models of New Physics that remain associated to
different ``trajectories" in the plane of the variations of the two parameters.
This is shown in particular for some popular SUSY and technicolor-type models.
In general, this discrimination is possible if a measurement of
\underline{both} parameters is performed.


title: A Transport Equation for Quantum Fields with Continuous Mass Spectrum

abstract:
  Within a relativistic real-time Green's function formalism, a quantum
transport equation for the phase-space distribution function is derived without
a quasi-particle approximation. Dissipation is due to a nonzero spectral width,
and can be separated into time-local and memory effects.


title: Hidden Higgs Particle

abstract:
  A modification of the standard model of electroweak interactions with the
nonlocal Higgs sector is proposed. Proper form of nonlocality makes Higgs
particles unobservable after the electroweak symmetry breaking. They appear
only as a virtual state because their propagator is an entire function. We
discuss some specific consequences of this approach comparing it with the
conventional standard model.


title:
On The $Q^2$ Dependence of The Spin Structure Function In The Resonance
  Region

abstract:
  In this paper, we show what we can learn from the CEBAF experiments on
spin-structure functions, and the transition from the Drell-Hearn-Gerasimov sum
rule in the real photon limit to the spin dependent sum rules in the deep
inelastic scattering, and how the asymmetry $A_1(x,Q^2)$ approaches the scaling
limit in the resonance region. The spin structure function in the resonance
region alone can not determine the spin-dependent sum rule due to the kinematic
restriction of the resonance region. The integral $\int_0^1 \frac
{A_1(x,Q^2)F_2(x,Q^2)}{2x(1+R(x,Q^2))}dx$ is estimated from $Q^2=0$ to $2.5$
GeV$^2$. The result shows that there is a region where both contributions from
the baryon resonances and the deep inelastic scattering are important, thus
provides important information on the high twist effects on the spin dependent
sum rule.


title: Intrinsic Charm In Proton and $J/\psi$ Photoproduction at High Energies

abstract:
  Based on a perturbative theory of quantum chromodynamics and non-relativistic
quark model, associated $J/\psi$ plus open charm photoproduction on charm
quarks in a proton via partonic subprocess $\gamma c\to J/\psi c$ is discussed.
It is shown that the value and energy dependence of the cross section for such
process remarkably depends on the choice of charm distribution function in a
proton. In the region of small $z=E_J/E_{\gamma}<0.2$ the contribution of the
$\gamma c\to J/\psi c$ subprocess in the inelastic $J/\psi$ photoproduction
spectra is larger than the contribution of the photon-gluon fusion subprocess.
At the energy range of HERA collider intrinsic charm contribution in the total
inclusive $J/\psi$ photoproduction cross section may be equal to 4\% of the
dominant contribution of photon-gluon fusion mechanism.


title: Excited $\Lambda_Q$ Baryons in the Large $N_c$ Limit

abstract:
  The spectrum of excited $\Lambda_Q$-type heavy baryons is considered in the
large $N_c$ limit. The universal form factors for $\Lambda_b$ semileptonic
decay to excited charmed baryons are calculated in the large $N_c$ limit. We
find that the Bjorken sum rule (for the slope of the Isgur--Wise function) and
Voloshin sum rule (for the mass of the light degrees of freedom) are saturated
by the first doublet of excited $\Lambda_Q$ states.


title: Vacuum Oscillations and Future Solar Neutrino Experiments

abstract:
  Vacuum oscillations are considered for the combined solar neutrino
observations, including the Kamiokande II spectrum data and incorporating
theoretical uncertainties and their correlations. Despite the conceptual
difficulty of the fine tuning between the neutrino parameters and the Sun-Earth
distance, 2-flavor vacuum oscillations provide phenomenologically acceptable
solutions. There are allowed regions at 99\% C.L. for $\Delta m^2 = (0.45 -
1.2) \times 10^{-10} \; \mbox{eV}\,^2$ and $\sin^22\theta = 0.6 - 1$; the best
fit solution is $\chi^2 / \mbox{d.f.} = 19.2 / 16$, which is acceptable at 16\%
C.L. Oscillations for sterile neutrinos are, however, excluded by the averaged
data at 99.4\% C.L. The vacuum oscillation solutions predict characteristic
energy spectrum distortions and seasonal variations in Sudbury Neutrino
Observatory, Super-Kamiokande, and BOREXINO. Those predictions are given in
detail, emphasizing that the vacuum solutions are distinguishable from the MSW
solutions.


title: Heavy Quark Distribution Functions from QCD

abstract:
  The structure function of a heavy quark in a heavy hadron in
electroproduction is calculated from QCD. Its deviation from the parton model
prediction (a delta function) is shown to be governed by a shape function,
similar to the one recently proposed by Neubert and Bigi {\em et al.} to
describe the end-point behaviour of the lepton spectrum in semileptonic $B\to
X_ue\bar\nu$ decays and the line shape in $B\to X_s\gamma$. Two new sum rules
are derived which extend the Bjorken-Dunietz-Taron sum rule by including
corrections suppressed by the inverse heavy quark mass.


title: Precision Electroweak Tests on the $Sp(6)_L \times U(1)_Y$ Model

abstract:
  We perform precision electroweak tests on the $Sp(6)_L \times U(1)_Y$ model.
The purpose of the analysis is to delineate the model parameters such as the
mixing angles of the extra gauge bosons present in this model. We find that the
model is already constrained considerably by the present LEP data.


title:
Quantum Effects on Higgs-Boson Production and Decay due to Majorana
  Neutrinos

abstract:
  We analyze the phenomenological implications for new electroweak physics in
the Higgs sector in the framework of SU(2)_L x U(1)_Y theories that naturally
predict heavy Majorana neutrinos. We calculate the one-loop Majorana-neutrino
contributions to the decay rates of the Higgs boson into pairs of quarks and
intermediate bosons and to its production cross section via bremsstrahlung in
e^+e^- collisions. It turns out that these are extremely small in three-
generation models. On the other hand, the sizeable quantum corrections
generated by a conventional fourth generation with a Dirac neutrino may be
screened considerably in the presence of a Majorana degree of freedom.


title: Photon Radiation in a Heat Bath

abstract:
  We discuss the bremsstrahlung of photons into a heat bath, and calculate from
first principles the energy radiated. Even to lowest order the spectrum of the
radiation at low frequency is no more singular than at zero temperature. In
addition to the obvious contributions, this spectrum includes terms associated
with fluctuations. [Revised version has additional explanations]


title:
Quantum electrodynamics in the squeezed vacuum state: Feynman rules and
  corrections to the electron mass and anomalous magnetic moment

abstract:
  Due to the nonvanishing average photon population of the squeezed vacuum
state, finite corrections to the scattering matrix are obtained. The lowest
order contribution to the electron mass shift for a one mode squeezed vacuum
state is given by $\delta m(\Omega ,s)/m=\alpha (2/\pi )(\Omega
/m)^2\sinh^2(s)$, where $\Omega$ and $s$ stand for the mode frequency and the
squeeze parameter and $\alpha$ for the fine structure constant, respectively.
The correction to the anomalous magnetic moment of the electron is $\delta
a_e(s)=-(4\alpha /\pi )\sinh^2(s)$.


title: CP-odd effective gluonic Lagrangian in Kobayashi-Maskawa model

abstract:
  Schwinger operator method is applied for studying CP-odd pure gluonic
effective Lagrangian in the Standard Model at three-loop level. The induced
$\theta$-term vanishes by the same reasons as EDMs of quark and W-boson to
two-loop approximation. A simple way is found to demonstrate these
cancellations. All other terms of the effective Lagrangian acquire
non-vanishing contributions. The effective operator of dimension six, Weinberg
operator, is calculated explicitly. The corresponding contribution to the EDM
of neutron is much smaller than that comes from large distances.


title:
The Reaction $\gamma\gamma\to\pi^0\pi^0$ in Generalized Chiral
  Perturbation Theory

abstract:
  The cross section for $\gamma\gamma\to\pi^0\pi^0$ and the pion
polarizabilities are computed, within generalized chiral perturbation theory,
in the full one loop approximation, {\it i.e.} up to and including order
$O({p^5})$. The result depends on the parameter ${\alpha}_{\pi\pi}$ defining
the tree level $\pi - \pi$ scattering amplitude and on an additional low energy
constant. The latter is shown to be related by an exact sum-rule to the $e^+
e^-$ data. The parameter ${\alpha}_{\pi\pi}$ is related to the quark mass ratio
$r = m_s /{\hat m}$ via the expansion of pseudoscalar meson masses. The
generalized one loop $\gamma\gamma\to\pi^0\pi^0$ amplitude agrees with the
experimental data in the threshold region provided $r= {m_s}/{\hat m}\lapprox
10$. Higher order corrections are estimated comparing our calculation with the
dispersive approach.


title: Effects of technicolor on standard model running couplings

abstract:
  We discuss the running couplings in the standard model, SU(3$)_C \times
$SU(2$)_L \times $U(1$)_Y$, when the Higgs sector is replaced by SU($N_{TC})$
technicolor. Particular attention is given to the running of the couplings at
momentum scales where technicolor is nonperturbative, and in this region we
apply a relativistic constituent technifermion model. This model has been
tested against the known running of the QED coupling due to nonperturbative
QCD. An understanding of this low momentum running allows the calculation of
the couplings at a higher scale, $\Lambda_{pert}$, where technicolor becomes
perturbative. We provide numerical values for the changes in the three standard
model couplings between $m_Z$ and $\Lambda_{pert}$ due to technicolor, assuming
separately ``one doublet'' and ``one family'' technicolor models. The
distinction between a running and walking technicolor coupling is also
considered.


title: 2+1 Dimensional QED and a Novel Phase Transition

abstract:
  We investigate the chiral phase transition in 2+1 dimensional QED. Previous
gap equation and lattice Monte-Carlo studies of symmetry breaking have found
that symmetry breaking ceases to occur when the number of fermion flavors
exceeds a critical value. Here we focus on the order of the transition. We find
that there are no light scalar degrees of freedom present as the critical
number of flavors is approached from above (in the symmetric phase). Thus the
phase transition is not second order, rendering irrelevant the renormalization
group arguments for a fluctuation induced transition. However, the order
parameter vanishes continuously in the broken phase, so this transition is also
unlike a conventional first order phase transition.


title: Nuclear Shadowing in a Parton Recombination Model: Q$^2$ Variation

abstract:
  Q$^2$ variation of the nuclear-structure-function ratio
$F_2^A(x,Q^2)/F_2^D(x,Q^2)$ is investigated in a parton model with
Q$^2$-rescaling and parton-recombination effects. Calculated results are
compared with the NMC (New Muon Collaboration) and the Fermilab-E665
experimental data. We find that our theoretical results show small Q$^2$
variations and that they are consistent with the data within present
experimental accuracy.


title: Heavy Quark Hadronic Weak Decays from CLEO-II

abstract:
  We present preliminary results from the CLEO-II collaboration on a variety of
hadronic final states of mesons containing heavy quarks. In particular, the
pattern of 2-body \B\ decays is now decisively different that that of \D\ and
\K\ decays; perhaps a consequence will be that $\tau_{\BM}<\tau_{\BZB}$. We
have observed `wrong-sign' $\DZ\sto\KP\PIM$ decays, which are probably due to a
doubly Cabibbo-suppressed transition.


title: Potential Minimization in Left-Right Symmetric Models

abstract:
  We study the Higgs potentials in the Left-Right symmetric model for various
choices of Higgs fields. We give emphasis to the cases when the Higgs field
$\xi=(2,2,15)$ is included to give the correct relations of quark masses and a
singlet field $\eta$ which breaks the left-right parity. As special cases we
also include $\xi^\prime=(2,2,15)$ and $\chi=(2,2,6)$ (which are interesting in
the context of the three lepton decay mode of the proton) and field
$\delta=(3,3,0)$ none of which acquire {\it vev}. We show that the linear
couplings of these fields upon minimization put fine tuning conditions on the
parameters of the model. We carry out the minimization of these potentials
explicitly. In all the cases the relationship between the {\it vev$\;$}s of the
left and right handed triplets $v_L$ and $v_R$ are given. The phenomenological
consequences of this minimization regarding the neutrino masses are also
studied.


title: The BFKL and GLDAP regimes for the perturbative QCD pomeron

abstract:
  The $S$-matrix of diffractive scattering is diagonalized in terms of the
colour dipole-dipole cross section. Recently, we have shown that the dipole
cross section satisfies the generalized BFKL equation. In this paper we discuss
the spectrum and solutions of our generalized BFKL equation with allowance for
the finite gluon correlation radius $R_{c}$. The latter is introduced in the
gauge invariant manner. We present estimates of the intercept of the pomeron
and find the asymptotic form of the dipole cross section. We consider the
difference between the BFKL and GLDAP evolutions and conclude that the GLDAP
evolution remains a viable description of deep inelastic scattering well beyond
the kinematical range of the HERA experiments. We suggest methods of measuring
the pomeron intercept in the HERA experiments.


title: QCD corrections to direct B -> J/Psi decays

abstract:
  We calculate next to leading order QCD corrections to the direct decays b ->
J/Psi + X and b -> eta_c + X. The strong renormalization scale dependence is
seen to persist also in this order and in fact the rate is driven to an
unphysical negative value at the M_b scale. We show that this is a consequence
of the strong suppression and scale dependence in the leading order term. Large
cancellations take place between terms from three different orders in alpha_s.
Lacking a third order calculation we are forced to throw away the leading order
term and all but one of the next to leading order terms. The remaining ccbar
gluon emission term could very well be the dominant one. Even if this is not
the case, the picture of a rate at least as suppressed as in the leading
logarithmic approximation survives.


title: Distributions of leptons in decays of polarised heavy quarks

abstract:
  Analytic formulae are given for QCD corrections to the lepton spectra in
decays of polarised up and down type heavy quarks. These formulae are much
simpler than the published ones for the corrections to the spectra of charged
leptons originating from the decays of unpolarised quarks and polarised up type
quarks. Distributions of leptons in semileptonic $\Lambda_c$ and $\Lambda_b$
decays can be used as spin analysers for the corresponding heavy quarks. Thus
our results can be applied to the decays of polarised charm and bottom quarks.
For the charged leptons the corrections to the asymmetries are found to be
small in charm decays whereas for bottom decays they exhibit a non-trivial
dependence on the energy of the charged lepton. Short life-time enables
polarisation studies for the top quark. Our results are directly applicable for
processes involving polarised top quarks.


title: Small Flavor Conserving CP Violation in Superstring Models

abstract:
  It is well known that supersymmetric models allow new sources for CP
violation that arise from soft supersymmetry breaking terms. If unsuppressed,
these new CP-violating phases would give too large a neutron electric dipole
moment. We discuss a mechanism for suppressing SUSY phases in string-inspired
supergravity models in which supersymmetry is assumed to be broken by the
auxiliary components of the dilaton and moduli superfields. (To appear in the
Proceeding of the Third KEK Topical Conference on CP Violation, its Implication
to Particle Physics and Cosmology)


title: Skyrmion solutions by generalization of the Atiyah-Manton ansatz

abstract:
  We generalize the approach of Atiyah and Manton for generating Skyrmion
configurations from instantons. The result is a series which parameters are
found directly from the chiral angle equation. The series converge rapidly to
the exact solution for a class of the Skyrme-like models (including the Skyrme
model itself) but describe with less accuracy other types of models. We
describe the procedure and discuss its advantages and limitations.


title: Uncertainties in testing QCD with the photon structure function

abstract:
  We review the different approaches used to treat the photon structure
function. We suggest that despite some uncertainties it should remain sensitive
to $\Lambda .$


title: Gluons from logarithmic slopes of $F_{2}$ in the NLL approximation

abstract:
  We make a critical, next-to-leading order, study of the accuracy of the Prytz
relation, which is frequently used to extract the gluon distribution at small
$x$ from the logarithmic slopes of the structure function $F_{2}$. We find that
the simple relation is not generally valid in the Hera regime, but show that it
is a reasonable approximation for gluons which are sufficiently singular at
small $x$.


title:
Exclusive W + photon production in proton-antiproton collisions I:
  general formalism

abstract:
  We present a detailed computation of the fully exclusive cross section of p +
antip --> W + photon + X with X = 0 and 1 jet in the framework of the
factorization theorem and dimensional regularization. Order alpha-strong and
photon bremsstrahlung contributions are discussed in the MS-bar mass
factorization scheme. The resulting expressions are ready to be implemented
numerically using Monte Carlo techniques to compute single and double
differential cross sections and correlations between outgoing pairs of
particles.


title:
"Nucleosynthesis constraints on active-sterile neutrino conversions in
  the early universe with random magnetic field"

abstract:
  We consider active-sterile neutrino conversions in the early universe hot
plasma in the presence of a random magnetic field generated at the electroweak
phase transition. Within a random field domain the magnetization asymmetry of
the lepton antilepton plasma produced by a uniform constant magnetic field is
huge in contrast to their small density asymmetry, leading to a drastic change
in the active-sterile conversion rates. Assuming that the random field provides
the seed for the galactic field one can estimate the restrictions from
primordial nucleosynthesis. Requiring that the extra sterile \neu does not
enter in equilibrium with the active ones before nucleosynthesis we find limits
of the oscillation parameters which are stronger than in the isotropic case.


title: SO(10) grand unification model for degenerate neutrino masses

abstract:
  This version corrects the first one in eq.3.4 and table 1 where there was a
bar missing in the 126 representation. All other equations and results are
unchanged and correct. However, the criticism we had made in the earlier
version to the work of Caldwell and Mohapatra was not correct and has been
removed from the "note added" where it appeared. Moreover one new reference has
been added to ref.13.


title: Top Radiative Corrections in Non-minimal Standard Models

abstract:
  We derive the one-loop effective action induced by a heavy top in models with
an extended Higgs sector. We use the effective action to analyze the top
corrections to the $\rho$ parameter and to the Higgs-gauge boson couplings. We
show that in models with $\rho\not=1$ at tree-level, one does not lose
generally the bound on $m_t$ from the $\rho$ parameter.


title: Green's Functions in the Color Field of a Large Nucleus

abstract:
  We compute the Green's functions for scalars, fermions and vectors in the
color field associated with the infinite momentum frame wavefunction of a large
nucleus. Expectation values of this wavefunction can be computed by integrating
over random orientations of the valence quark charge density. This relates the
Green's functions to correlation functions of a two dimensional, ultraviolet
finite, field theory. We show how one can compute the sea quark distribution
functions, and explictly compute them in the kinematic range of transverse
momenta, $\alpha_s^2 \mu^2 << k_t^2 << \mu^2$, where $\mu^2$ is the average
color charge squared per unit area. When $m_{quark}^2 << \mu^2 \sim A^{1/3}$,
the sea quark contribution to the infinite momentum frame wave function
saturates at a value that is the same as that for massless sea quarks.


title:
Second Order Perturbation Corrections to Baryon Mass Spectrum in
  Skyrmion Quantum Mechanics

abstract:
  The corrections to the Gell-Mann-Okubo relations of baryon-masses are
presented in the SU(3) Skyrme model. These corrections are calculated up to the
second order in flavor breaking at the skyrmion quantum mechanics. The results
are compatible with the experimental data. They could be regarded as a signal
of existence of some obscure SU(3)-multiplets: 27-let(with spin 1/2 or
3/2),10$^*$-let(with spin 1/2) and 35-let(with spin 3/2).


title: Chiral invariant renormalization of the pion--nucleon interaction

abstract:
  The leading divergences of the generating functional for Green functions of
quark currents between one--nucleon states are calculated with heat kernel
techniques. The results allow for a chiral invariant renormalization of all
two--nucleon Green functions of the pion--nucleon system to $O(p^3)$ in the
low--energy expansion.


title:
Exclusive W^+ + photon production in proton-antiproton collisions II:
  results

abstract:
  We present results for total cross sections, single and double differential
distributions and correlations between pairs of outgoing particles in the
reactions p + antip --> W^+ + photon and p + antip --> W^+ + photon + jet at
sqrt(S)=1.8 TeV. Order alpha-strong QCD corrections and leading logarithm
photon bremsstrahlung contributions are included in the MS-bar mass
factorization scheme for three experimental scenarios: 1) 2-body inclusive
production of W^+ and photon, 2) exclusive production of W^+, photon and 1 jet
and 3) exclusive production of W^+ and photon with 0 jet.
  The latest CTEQ parton distribution functions, which fit the newly released
HERA data, are used in our analysis. The dependence of our results on the mass
factorization scale is used to place error bars on our predictions for the
single differential distributions and correlations.


title: The Phenomenology of the CP-odd Scalar of Two-Doublet Models

abstract:
  We examine the phenomenology of the $CP$-odd scalar $A^0$ of
two-Higgs-doublet models. We explore the parameter space determined by
triviality bounds and identify the regions where the $A^0$ can be detected at
the LHC in each of the following modes: the inclusive two-photon decay mode,
the $l^{\pm}\gamma\gamma X$ mode from $t\overline{t}A^0$ production and the
$A^0\rightarrow Zh$ channel with the subsequent decay of the $CP$-even scalar
$h$ to two photons. We find that, while the $l^{\pm}\gamma\gamma X$ mode is of
limited usefulness, the other two modes can give viable signals in fairly
large, and complementary, regions of parameter space.


title: Chiral and Heavy Quark Symmetry Violation in B Decays

abstract:
  The most general Lagrangian consistent with chiral, heavy quark, and strong
interaction symmetries to order $1/M$ and to linear order in the SU(3) vector
and axial currents is presented. Two new dimensionful and five dimensionless
couplings arise at this order. The heavy to light flavor changing current is
derived to the same order, giving rise to two additional dimensionful constants
and six dimensionless ones. The dimensionless parameters are shown to be
irrelevant at \ord. The leading nonanalytic heavy quark and chiral symmetry
violating corrections to heavy meson decay constants are computed, and
implications to B decays are discussed; measurements of the experimentally
accessible form factors for $D \to \pi l \nu$ and $B \to \pi l \nu$, along with
knowledge of the $D^* D \pi$ coupling, determine the eight decay constants
$f_D$, $f_{D_s}$, $f_{D^*}$, $f_{D_s^*}$, $f_B$, $ f_{B_s}$, $f_{B^*}$, and
$f_{B_s^*}$, as well as one relation among the $B \to \pi l \nu$ form factors,
to \ord~. The ratio $R_1 = \frac{f_{B_s}}{f_B}/\frac{f_{D_s}}{f_D}$ is
expressed in terms of two dimensionful couplings.


title: Electroweak Supersymmetric Quantum Corrections to the Top Quark Width

abstract:
  Within the framework of the MSSM, we compute the electroweak one-loop
supersymmetric quantum corrections to the width $\Gamma (t\rightarrow W^{+}\,
b)$ of the canonical main decay of the top quark. The results are presented in
two on-shell renormalization schemes parametrized either by $\alpha$ or $G_F$.
While in the standard model, and in the Higgs sector of the MSSM, the
electroweak radiative corrections in the $G_F$-scheme are rather insensitive to
the top quark mass and are of order of $1\%$ at most, the rest (``genuine''
part) of the supersymmetric quantum effects in the MSSM amount to a
non-negligible correction that could be about one order of magnitude larger,
depending on the top quark mass and of the region of the supersymmetric
parameter space. These new electroweak effects, therefore, could be of the same
order (and go in the same direction) as the conventional leading QCD
corrections.


title:
The Jacobi Polinomials QCD Analysis of the CCFR Data for xF_3 and the
  Q^2-Dependence of the Gross-Llewllyn Smith Sum Rule

abstract:
  We present the results of our QCD analysis of the recent CCFR data for the
structure function $xF_3 (x,Q^2)$ of the deep-inelastic neutrino--nucleon
scattering. The analysis is based on the Jacobi polynomials expansion of the
structure functions. The concrete results for the parameter $\Lambda_{\overline
{MS}}^{(4)}$ and the shape of quark distributions are determined. At the
reference scale $|Q_0^2|$=3 $GeV^2$ our results are in satisfactory agreement
with the ones obtained by the CCFR group with the help of another method. The
$Q_0^{2}$-dependence of the experimental data for the Gross--Llewellyn Smith
sum rule is extracted in the wide region of high-momentum transfer. Within
systematical experimental uncertainties the results obtained are consistent
with the perturbative QCD predictions. We reveal the effect of the discrepancy
between our results and the analysed perturbative QCD predictions at the level
of the statistical error bars. The importance of taking account, in our
procedure, of a still unknown next-next-to-leading approximation of the moments
of the structure function $xF_3 (x,Q^2)$ is stressed.


title:
A High Statistics Lattice Calculation of $f^{static}_B$ at $\beta=6.2$
  Using the Clover Action

abstract:
  We present a calculation of $f_B$ in the static limit, obtained by numerical
simulation of quenched QCD, at $\beta=6.2$ on a $18^3 \times 64$ lattice, using
the SW-Clover quark action. The decay constant has been extracted by studying
heavy(static)-light correlation functions of different smeared operators, on a
sample of 220 gauge field configurations. We have obtained $f_B^{static}=(290
\pm 15 \pm 45)$ MeV, where the first error comes from the uncertainty in the
determination of the matrix element and the second comes from the uncertainty
in the lattice spacing. We also obtain $M_{B_s}-M_{B_d}= (70 \pm 10)$ MeV and
$f^{stat}_{B_s}/f^{stat}_{B_d}=1.11(3)$. A comparison of our results with other
calculations of the same quantity is made.


title: Changes in the radius of a nucleon in interaction with another nucleon

abstract:
  We consider a two-nucleon system described by two different skyrmion models
that provide attraction for the central NN potential. One of these models is
based on the product ansatz and the other on dilaton coupling. Within these
models we ask the question, To what degree does the nucleon swell or shrink
when the internucleon separation distance is appropriate to attraction or
repulsion? We find typically swelling of 3 to 4 percent for central attraction
of some 40 to 50 MeV.


title:
High Precision $J/\psi$ and $\Upsilon$-production data and the Nuclear
  Glue

abstract:
  We use the high statistics E-772 data on the nuclear dependence of the
production of quarkonia $(J/\psi$ and $\Upsilon)$ and dimuons at large
transverse momentum $(p_T)$ in $p$-$A$ collisions to get information about the
gluonic EMC effect. We find a satisfactory quantitative agreement of the
theoretical predictions with the data although none of the models of the EMC
effect we consider could account for the entire data. Since all the qualitative
features are understood none the less in terms of perturbative QCD with nuclear
dependent parton densities, our results suggest that these data can now be used
for a better determination of the nuclear parton densities. Our conslusions are
shown to be insensitive to the hadronisation mechanism for the quarkonia.


title: A New Tool for the Lamb Shift Calculation

abstract:
  We solve the Bethe-Salpeter equation for hydrogenic bound states by choosing
an appropriate interaction kernel $K_c$. We want to use our solution to
calculate up to a higher order the hydrogen Lamb-shift, and as a first
application we present up to order $\left(\aa / \pi\right)(\za)^7$ the
contribution of the lowest order self-energy graph, calculated {\it exactly}.
The basic formalism is a natural extension to the hydrogenic bound states of
the one previously presented by R. Barbieri and E. Remiddi and used in the case
of positronium.


title: Direct CP Violation in K_L --> \pi^0 e^+e^- Beyond Leading Logarithms

abstract:
  We analyze the direct CP violation in the rare decay K_L --> Pi^0 e+e- with
QCD effects taken into account consistently in the next-to-leading order. We
calculate the two-loop mixing between the four-quark \Delta S=1 operators and
the operator Q_7V = (sd)_(V-A)(ee)_V in the NDR and HV renormalization schemes.
Using the known two-loop anomalous dimension matrix of the four-quark
operators, we find that the coefficient C_7V(\mu) depends only very weakly on
\mu, renormalization scheme and \Lambda_MSbar. The next-to-leading QCD
corrections enhance the direct CP violating contribution over its leading order
estimate so that it remains dominant in spite of the recent decrease of
|V_ub/V_cb| and |V_cb|. We expect typically BR(K_L --> \pi^0 e^+ e^-)_dir ~
6*10^(-12), although values as high as 10^(-11) are not yet excluded.


title: Naturally Small $x_s$?

abstract:
  Within the Standard Model, $x_s$ (the mixing parameter in the $B_s-\bar B_s$
system) is constrained to the range $7 \leq x_s\leq 40$. We point out that if
New Physics contributes significantly to $x_d$ (the mixing parameter in the
$B_d-\bar B_d$ system), then $2 \leq x_s\leq 7$ is possible without any
fine-tuned cancellations between the Standard Model and the New Physics
contributions.


title: A Vision for High Energy Physics

abstract:
  Following the termination of the Superconducting Super Collider, there is an
urgent need to develop a strategic plan for the future of high energy physics
and an accompanying vision to guide the priorities of the U.S. program. This
document proposes such a strategic plan and presents a singular opportunity for
the U.S. program. The existing hadron collider at Fermilab could be upgraded to
create a major discovery potential for supersymmetry, one of the most profound
concepts in the world of elementary particles. Using a single ring of SSC
magnets in the existing tunnel, the recently improved understanding of SUSY
phenomenology, and the upgraded detectors in place at the Tevatron, the
DiTevatron could be doing physics within five years and reach most of the range
of parameters permitted in SUSY models. We propose that it be funded as a
worthy component of the SSC termination, bringing to fruition both the
technology and the science of the SSC at very modest cost.


title:
Theoretical Expectations For High Mass Photon Pairs in L+ L- Gamma Gamma
  Events at LEP/SLC

abstract:
  Recently, the L3 collaboration has reported the observation of four events in
the reactions e+ e- --> L+ L- + (2 Photons), L = e, mu, tau, with the invariant
photon pair mass near 60 GeV in a data sample collected in the L3 detector
corresponding to 950,000 produced Z0's. More recently, more data from the other
LEP collaborations have become available. In this paper, we use the Monte Carlo
genrator YFS3 and our recent exact results on e+ e- --> L+ L- + (2 Photons) to
assess the QED expectations for such L3-type high mass photon pair events in e+
e- --> L+ L- + (n Photons) near the Z0 resonance.


title:
DTUJET--93 Sampling inelastic proton--proton and antiproton--proton
  collisions according to the two--component Dual Parton Model

abstract:
  A new version of a Monte Carlo Program for hadronic multi-particle production
is presented. It is based on the two-component Dual Parton Model which includes
the dual topological unitarization of soft and hard cross sections. The model
treats both soft (low $p_{\perp}$) and hard (minijet, large $p_{\perp}$)
processes in a unified and consistent way. The unified description is important
at TeV-energies of hadron colliders, where the hard perturbative cross sections
of QCD become large and comparable to the total cross sections.


title: On the Singular Behaviour of Structure Functions at Low X

abstract:
  We discuss the phenomenological extraction of the leading $ j$-plane
singularity from singlet structure functions $ F_s $ measured at small $ x. $
Using a saddle-point method we show that $ {\rm d ln} F_s /{\rm d ln}{1 \over
x} $ is a suitable observable for this purpose in the region $x \le 10^{-2}.$
As an application, we confront and distinguish in a model-independent way
structure function parametrizations coming from two different QCD evolution
equations, namely the Lipatov (or BFKL) equation and the Gribov-Lipatov
-Altarelli-Parisi (or GLAP) equation. Recent results at HERA are discussed in
this framework.


title:
Implications of Recent Nucleon Spin Structure Measurements for
  Neutralino Dark Matter Detection

abstract:
  Predicted rates for direct and indirect detection of dark-matter neutralinos
depend in general on the spin content of the nucleon. Neutralinos that are
predominantly $B$-ino are the likeliest candidates for detection via
spin-dependent interactions. Uncertainties in the measured spin content of the
nucleon may lead to dramatic uncertainties in the rates for detection of
$B$-inos by scattering off of nuclei with unpaired neutrons. Rates for
spin-dependent scattering of $B$-inos off of nuclei with unpaired protons are
far more robust, as are rates for capture of $B$-inos in the Sun.


title: The Isospin Splittings of Heavy-Light Quark Systems

abstract:
  The mass splittings of the pseudoscalar and vector D and B light-heavy quark
systems have been calculated using the method of QCD sum rules.
Electromagnetic, quark mass, and nonperturbative QCD effects are all included.
The results are in good agreement with experiment. A measurement of isospin
splitting for the vector B mesons would give valuable information about quark
mass splittings.


title: Solar and atmospheric neutrinos

abstract:
  Possible explanations of solar neutrino and atmospheric neutrino anomalies
are summarized and future tests discussed.


title:
Corrections to mass scale predictions in SO(10) GUT with higher
  dimensional operators

abstract:
  We calculate the two loop contribution to the predictions of the mass scales
in an SO(10) grand unified theory. We consider the modified unification scale
boundary conditions due to the non-renormalizable higher dimensional terms
arising from quantum gravity or spontaneous compactification of extra
dimensions in Kaluza-Klein type theory. We find the range of these couplings
which allows left-right symmetry to survive till very low energy (as low as
$\sim$ TeV) and still be compatible with the latest values of $\sin^2 \theta_W$
and $\alpha_s$ derived from LEP. We consider both the situation when the
left-right parity is broken and conserved.We consider both supersymmetric and
non-supersymmertic versions of the SO(10) theory.Taking the D-conserved
non-susy case as an example we calculate the effects of moderate threshold
uncertainties at the heavy scale, due to the unknown higgs masses,on the
gravity induced couplings.


title: Dynamical Symmetry Breaking in an E_6 GUT Model

abstract:
  Dynamical symmetry breaking is studied in an E_6 GUT model of a single
generation of fermions with strong 4-fermi interactions. The effective
potential is analyzed analytically by the help of Michel's conjecture and the
result is confirmed numerically. We find that the E_6 symmetry is spontaneously
broken either to F_4 or to Sp(8) or G_2 or SU(3), depending on which of the
4-fermi coupling constants G_27 and G_351 in the 27/351 channels is stronger.
The possibilities for obtaining other type of breaking patterns are also
discussed.


title: Signals of $CP$ violation in Higgs decay

abstract:
  We consider an extension of the Standard Model where some Higgs particle is
not an eigenstate of $CP$, and discuss the possibility of extracting signals of
the resulting $CP$ violation. In the case of Higgs decay to four fermions we
study correlations among momenta of the final-state fermions. We discuss
observables which may demonstrate presence of $CP$ violation and identify a
phase shift $\delta$, which is a measure of the strength of $CP$ violation in
the Higgs-vector-vector coupling, and which can be measured directly in the
decay distribution. In addition to these angular correlations, we consider
correlations between energy differences. The former correlations include some
recently reported results, whereas the latter ones appear to provide a much
better probe for revealing $CP$ violation.


title: Neutrino Mass

abstract:
  We review the issue of neutrino mass by concentrating on the minimal
extensions of the standard model. In particular, we emphasize the role that
gravitation may play in this regard and discuss the central aspects of the
see-saw mechanism of generating neutrino mass, including the possibility of the
see-saw scale being close to the eelectroweak scale.


title: The Pole Mass of The Heavy Quark. Perturbation Theory and Beyond

abstract:
  The key quantity of the heavy quark theory is the quark mass $m_Q$. Since
quarks are unobservable one can suggest different definitions of $m_Q$. One of
the most popular choices is the pole quark mass routinely used in perturbative
calculations and in some analyses based on heavy quark expansions. We show that
no precise definition of the pole mass can be given in the full theory once
non-perturbative effects are included. Any definition of this quantity suffers
from an intrinsic uncertainty of order $\Lam /m_Q$. This fact is succinctly
described by the existence of an infrared renormalon generating a factorial
divergence in the high-order coefficients of the $\alpha_s$ series; the
corresponding singularity in the Borel plane is situated at $2\pi /b$. A
peculiar feature is that this renormalon is not associated with the matrix
element of a local operator. The difference $\La \equiv M_{H_Q}-m_Q^{pole}$ can
still be defined in Heavy Quark Effective Theory, but only at the price of
introducing an explicit dependence on a normalization point $\mu$: $\La (\mu
)$. Fortunately the pole mass $m_Q(0)$ {\em per se} does not appear in
calculable observable quantities.


title: The Nonabelian Screening Potential Beyond the Leading Order

abstract:
  The nonabelian screening potential is calculated in the temporal axial gauge.
The Slavnov-Taylor identity is used to construct the three-gluon vertex
function from the inverse gluon propagator. After solving the Schwinger - Dyson
equation beyond leading order we find that the obtained momentum dependence of
the gluon self-energy at high temperature does not correspond to an attractive
QCD - Debye potential, but instead it is repulsive and power behaved ($ \simeq
1/r^6$) at large distance.


title:
Complete O(alpha_s^2) Corrections to (2+1) Jet Cross Sections in Deep
  Inelastic Scattering

abstract:
  Complete next-to leading order QCD predictions for (2+1) jet cross sections
and jet rates in deep inelastic scattering (DIS) based on a new parton level
Monte Carlo program are presented. All relevant helicity contributions to the
total cross section are included. Results on total jet cross sections as well
as differential distributions in the basic kinematical variables $x,W^2$ and
$Q^2$ are shown for HERA energies and for the fixed target experiment E665 at
FERMILAB. We study the dependence on the choices of the renormalization scale
$\mu_R$ and the factorization scale $\mu_F$ and show that the NLO results are
much less sensitive to the variation of $\mu=\mu_F=\mu_R$ than the LO results.
The effect of an additional $p_T$ cut to our jet definition scheme is
investigated.


title:
QCD corrections to inclusive $\Delta S=1,2$ transitions at the
  next-to-leading order

abstract:
  The 2--point functions for $\Delta S=1$ current-current and QCD-penguin
operators, as well as for the $\ds$ operator, are calculated at the
next-to-leading order. The calculation is performed in two different
renormalization schemes for $\gamma_5$, and the compatibility of the results
obtained in the two schemes is verified. The scale- and scheme-invariant
combinations of spectral 2--point functions and corresponding
Wilson-coefficients are constructed and analyzed. For $\Delta S=1$, the QCD
corrections to the CP-conserving part, dominated by current-current operators,
are 40\%--120\% at $q^2=\left(1-3\,\mbox{\rm GeV}\right)^2$, whereas the
correction to the imaginary part, mainly coming from the penguin operator
$Q_6$, are 100\%--240\%. The large size of the gluonic corrections to
current-current operators provides a qualitative understanding of the observed
enhancement of $\Delta I=1/2$ transitions. In the $\Delta S=2$ sector the QCD
corrections are quite moderate ($\approx -20\%$).


title:
Heavy Quark Effective Theory beyond Perturbation Theory: Renormalons,
  the Pole Mass and the Residual Mass Term

abstract:
  We study the asymptotic behaviour of the perturbative series in the heavy
quark effective theory (HQET) using the $1/N_f$ expansion. We find that this
theory suffers from an {\it ultraviolet} renormalon problem, corresponding to a
non-Borel-summable behaviour of perturbation series in large orders, and
leading to a principal nonperturbative ambiguity in its definition. This
ambiguity is related to an {\it infrared} renormalon in the pole mass and can
be understood as the necessity to include the residual mass term $\delta m$ in
the definition of HQET, which must be considered as ambiguous (and possibly
complex), and is required to cancel the ultraviolet renormalon singularity
generated by the perturbative expansion. The formal status of $\delta m$ is
thus identical to that of condensates in the conventional short-distance
expansion of correlation functions in QCD. The status of the pole mass of a
heavy quark, the operator product expansion for inclusive decays, and QCD sum
rules in the HQET are discussed in this context.


title: An SO(10)XS-4 Scenario for Naturally Degenerate Neutrinos

abstract:
  The simplest scenario for the three known light neutrinos that fits the solar
and atmospheric neutrino deficit and a mixed dark matter (MDM) picture of the
universe requires them to be highly degenerate with $m_{\nu} \sim$ 1 - 2 eV. We
propose an SO(10) grand unified model with an S$_{4}$-horizontal symmetry that
leads naturally to such a scenario.
  An explicit numerical analysis of the quark and lepton sector of the model
shows that it can lead to desired mass differences to fit all data only for the
small angle non-adiabatic MSW solution to the solar neutrino puzzle.


title: A Supersymmetric Effective Chiral Lagrangian

abstract:
  We construct in a manifestly supersymmetric form the leading and subleading
terms in momentum for an effective supersymmetric chiral Lagrangian in terms of
complex pions and their superpartners. A soft supersymmetry breaking term is
included and below the supersymmetry breaking scale the Lagrangian reduces to
the usual bosonic chiral Lagrangian in terms of real pions.


title:
Missing (up) Mass, Accidental Anomalous Symmetries, and the Strong CP
  Problem

abstract:
  We reconsider the massless up quark solution of the strong CP problem. We
show that an anomaly free horizontal symmetry can naturally lead to a massless
up quark and to a corresponding accidental anomalous symmetry. Reviewing the
controversy about the phenomenological viability of $m_u=0$ we conclude that
this possiblity is still open and can solve the strong CP problem. To appear in
the Proceedings of The Yukawa Couplings and the Origins of Mass Workshop.


title:
Multiple Gluon Effects in Fermion--(Anti)Fermion Scattering at SSC/LHC
  Energies

abstract:
  We extend the methods of Yennie, Frautschi and Suura (YFS) to compute, via
Monte Carlo methods, the effects of multiple gluon emission in the processes
$q+q'\to q''+q'''+n(G)$, where $G$ is a soft gluon. We show explicitly that the
infrared singularities in the respective simulations are canceled to all orders
in $\alpha_s$. Some discussion of this result from the standpoint of
confinement is given. More importantly, we present, for the first time ever,
sample numerical Monte Carlo data on multiple soft gluon emission in the
rigorously extended YFS framework. We find that such soft gluon effects must be
taken into account for precise SSC/LHC physics simulations.


title: Particle Physics Bounds from the Hulse-Taylor Binary

abstract:
  The orbital period of the binary pulsar PSR 1913+16 has been observed to
decrease at the rate of $2.40\times 10^{-12}$ s/s which agrees with the
prediction of the quadropole formula for gravitational radiation to within one
percent. The decrease in orbital period may also occur by radiation of other
massless particles like scalars and pseudoscalar Nambu-Goldstone bosons.
Assuming that this energy loss is less than one percent of the gravitational
radiation, we can establish bounds on couplings of these particles to nucleons.
For a scalar nucleon coupling of the form $g_s~\phi~\bar\psi~\psi$ we find that
$g_s< 3\times 10^{-19}$. From the radiation loss of massless Goldstone bosons
we establish the upper bound $\theta /f< 7.5\times 10^{-16}$ GeV$^{-1}$ on the
QCD vacuum angle $\theta$ and the scale $f$ at which the baryon number symmetry
can be broken spontaneously.


title: {\bf Consitutent Quarks, Chiral Symmetry and the Nucleon Spin$^{1, 2}$}

abstract:
  It is argued that the constituent quarks are expected to show a non-- trivial
spin and flavor structure, due to the anomalous breaking of the chiral symmetry
in the U(1) sector. CERN--TH.7079/93\\


title: About the Bethe Salpeter Formalism in the Heavy Mass Limit

abstract:
  We investigate the Bethe--Salpeter description of mesons in the limit where
one of the constituing quarks is infinitely heavy. To recover the
non--relativistic quark model out of the Bethe--Salpeter formalism it is usual
to assume that the potential is instantaneous and the Fock space is reduced to
$Q\bar{q}$ states. We show that in the Feynman gauge in perturbation theory and
for a heavy quark being on--mass shell the instantaneity of the potential is
valid in the rest--frame of the meson. Furthermore we argue that to first order
in the velocity exchange during a heavy meson transition, the error induced by
the reduction of the Fock--space is small. This in turn justifies quark model
calculations, even when one quark is light.


title: Hadrons with Charm and Beauty

abstract:
  By combining potential models and QCD spectral sum rules (QSSR), we discuss
the spectroscopy of the $(b\bar c)$ mesons and of the $(bcq)$, $(ccq)$ and
$(bbq)$ baryons (${q}\equiv {d}$ or $s$), the decay constant and the
(semi)leptonic decay modes of the $B_c$ meson. For the masses, the best
predictions come from potential models and read: $M_{B_c} = (6255 \pm 20)$~MeV,
$M_{B^*_c} = (6330 \pm 20)$~MeV, $M_{\Lambda(bcu)} = (6.93\pm 0.05)$~GeV,
$M_{\Omega(bcs)} = (7.00\pm 0.05)$~GeV, $M_{\Xi^*(ccu)} =(3.63\pm 0.05)$~GeV
and $M_{\Xi^*(bbu)} = (10.21\pm 0.05)$~GeV. The decay constant $f_{B_c} = (2.94
\pm 0.21) f_\pi $ is well determined from QSSR and leads to: $\Gamma(B_c
\rightarrow \nu_\tau \tau) = (3.0 \pm 0.4)( V_{cb}/0.037 )^2$ $\times 10^{10}$
s$^{-1}$.The uses of the vertex sum rules for the semileptonic decays of the
$B_c$ show that the $t$-dependence of the form factors is much stronger than
predicted by vector meson dominance. It also predicts the almost equal strength
of about 0.30 $\times 10^{10}$ sec$^{-1}$ for the semileptonic rates $B_c$ into
$B_s, B^*_s,\eta_c$ and J/$\psi$. Besides these phenomenological results, we
also show explicitly how the Wilson coefficients of the $\langle\alpha_s
G^2\rangle$ and $\langle G^3\rangle$ gluon condensates already contain the full
heavy quark- ($\langle\bar QQ\rangle$) and mixed- ($\langle\bar QGQ\rangle$)
condensate contributions in the OPE.}


title: Heterotic Approach to the Nucleon Distribution Amplitude

abstract:
  We give an in-depth analysis of the determination procedure of the recently
proposed heterotic nucleon distribution amplitude which hybridizes the best
features of the Chernyak-Ogloblin-Zhitnitsky and the Gari-Stefanis models. With
respect to the QCD sum-rule constraints, optimized versions of these amplitudes
are derived in terms of which a "hybridity" angle can be introduced to
systematically classify all models.


title: Evolution Effects on the Nucleon Distribution Amplitude

abstract:
  We study the Brodsky-Lepage evolution equation for the nucleon and construct
an eigenfunction basis by including contributions of up to polynomial order
$9$. By exployting the permutation symmetry $P_{13}$ of these eigenfunctions, a
basis of symmetrized Appell polynomials can be constructed in which the
diagonalization of the evolution kernel is considerably simplified. The
anomalous dimensions are calculated and found to follow a power-law behavior.
As an application, we consider the Brodsky-Huang-Lepage ansatz. An algorithm is
developed to properly incorporate such higher order contributions in a
systematic way.


title: Pepturbative and Nonperturbative Aspects of Exclusive Processes

abstract:
  Invited talk presented at the Workshop on Quantum Field Theoretical Aspects
of High Energy Physics, Kyffh\"auser, Germany, September 20-24, 1993; to be
published in the Proceedings.


title:
Bottom-Tau Yukawa Unification in the Next-to-Minimal Supersymmetric
  Standard Model

abstract:
  We discuss the unification of the bottom quark and tau lepton Yukawa
couplings within the framework of the next-to-minimal supersymmetric standard
model. We compare the allowed regions of the $m_t$-$\tan \beta$ plane to those
in the minimal supersymmetric standard model, and find that over much of the
parameter space the deviation between the predictions of two models is small,
and nearly always much less than the effect of current theoretical and
experimental uncertainties in the bottom quark mass and the strong coupling
constant. However over some regions of parameter space top-bottom Yukawa
unification cannot be achieved. We also discuss the scaling of the light
fermion masses and mixing angles, and show that to within current uncertainties
the results of recent texture analyses performed for the minimal model also
apply to the next-to-minimal model.


title: Generalised Factorial Moments and QCD Jets

abstract:
  { In this paper we present a natural and comprehensive generalisation of the
standard factorial moments ($\clFq$) analysis of a multiplicity distribution.
The Generalised Factorial Moments are defined for all $q$ in the complex plane
and, as far as the negative part of its spectrum is concerned, could be useful
for the study of infrared structure of the Strong Interactions Theory of high
energy interactions (LEP multiplicity distribution under the ${\cal Z}_0$). The
QCD calculation of the Generalised Factorial Moments for negative $q$ is
performed in the double leading log accuracy and is compared to OPAL
experimental data. The role played by the infrared cut-off of the model is
discussed and illustrated with a Monte Carlo calculation. }


title:
Astrophysical Searches For Exotic Phenomena In Ultrahigh Energy
  Neutrino-Nucleon Scattering

abstract:
  We investigate the potential of near-future neutrino telescopes like NESTOR
for searches for exotic processes in ultrahigh energy neutrino-quark
scattering. (NESTOR is the acronym for NEutrinos, from Supernovae and TeV
sources, Ocean Range ... a water Cherenkov detector to be constructed in the
Mediterranean off the coast of Greece). We consider signatures such as muon
bundles and/or contained cascades from the nonperturbative production of
multiple weak gauge bosons in the Standard Model, compositeness and leptoquark
production.


title: Cosmic Strings and Electroweak Baryogenesis

abstract:
  The electroweak symmetry is unbroken in the core of cosmic strings
originating from a symmetry breaking at an energy higher than the electroweak
scale $\eta_{EW}$. The dynamics of such strings may generate a baryon asymmetry
below the electroweak symmetry breaking scale. This mechanism for electroweak
baryogenesis is most efficient if the scale of string formation is only
slightly higher than $\eta_{EW}$ \eg \ in theories of dynamical symmetry
breaking) and if the strings are superconducting. The mechanism is also
effective if the electroweak phase transition is second order.


title: Level Crossing Along Sphaleron Barriers

abstract:
  In the electroweak sector of the standard model topologically inequivalent
vacua are separated by finite energy barriers, whose height is given by the
sphale\-ron. For large values of the Higgs mass there exist several sphaleron
solutions and the barriers are no longer symmetric. We construct paths of
classical configurations from one vacuum to a neighbouring one and solve the
fermion equations in the background field configurations along such paths,
choosing the fermions of a doublet degenerate in mass. As in the case of light
Higgs masses we observe the level crossing phenomenon also for large Higgs
masses.


title: Supersymmetric Singlet Majorons and Cosmology

abstract:
  We examine cosmological constraints on the lepton number breaking scale in
supersymmetric singlet majoron models. Special attention is drawn to the model
dependence arising from the particular choice of a certain majoron extension
and a cosmological scenario. We find that the bounds on the symmetry breaking
scale can vary substantially. Large values of this scale can be allowed if the
decoupling temperature of smajoron and majorino exceeds the reheating
temperature of inflation. In the opposite case an upper bound depending on the
majoron model can be obtained which, however, is unlikely to be much larger
than $10^{10}$ GeV.


title: Orsay lectures on confinement (I)

abstract:
  This is the first lecture of a serie on a theory of confinement, devoted to
the mechanism of supercharged nuclei as a model for particle binding.


title:
Finite Temperature Effective Potential to Order $g^4,\la^2$ and the
  Electroweak Phase Transition

abstract:
  The standard model effective potential is calculated at finite temperature to
order $g^4,\la^2$ and a complete zero temperature renormalization is performed.
In comparison with lower order calculations the strength of the first order
phase transition has increased dramatically. This effect can be traced back to
infrared contributions from typical non-Abelian diagrams and to the infrared
behaviour of the scalar sector close to the critical temperature. Several
quantities, e.g. surface tension, latent heat and field expectation value are
analyzed for an SU(2)-Higgs model and for the full standard model in detail. An
explicit formula enabling further analytic or numerical study is presented.
(DESY-94-025)