title:
The kinetic energy and and the geometric structure in the $B=2$ sector
  of the Skyrme model: A study using the Atiyah-Manton Ansatz

abstract:
  We study the construction of the collective-coordinate manifold in the baryon
number two sector of the Skyrme model. To that end we use techniques of
adiabatic large amplitude collective motion, which treat potential and kinetic
energy on an equal footing. In this paper the starting point is the Ansatz
proposed by Atiyah and Manton (Phys.~Lett.~{\bf 438B}, 222 (1989)), which
allows a study of the dynamics using a finite and small number of variables.
From these variables we choose a subset of collective ones. We then study the
behavior of inertial parameters along parts of the collective manifold, and
study the dynamical parts of the interaction.


title:
Once More on the Radiative Corrections to the Nucleon Structure
  Functions in QCD

abstract:
  A new representation of the next to leading QCD corrections to the nucleon
structure functions is given in terms of parton distributions. All
$~\alpha_{s}~$ corrections to the leading logarithmic approximation (LLA) are
included. In contrast to the similar representations in the literature terms of
order $~O(\alpha_{s}^{2})~$ do not attend in our expressions for the nucleon
structure functions taken in the next to leading logarithmic approximation.
This result is generelized for any order in $~\alpha_{s}~$ beyond the LLA.
Terms of order $~O(\alpha^{n}_{s})~$ which belong only to the approximation in
consideration are present in such a representation for the structure functions.


title: Dynamics of Baby Skyrmions

abstract:
  Baby Skyrmions are topological solitons in a (2+1)-dimensional field theory
which resembles the Skyrme model in important respects. We apply some of the
techniques and approximations commonly used in discussions of the Skyrme model
to the dynamics of baby Skyrmions and directly test them against numerical
simulations. Specifically we study the effect of spin on the shape of a single
baby Skyrmion, the dependence of the forces between two baby Skyrmions on the
baby Skyrmions' relative orientation and the forces between two baby Skyrmions
when one of them is spinning.


title: The Pomeron in QCD

abstract:
  In the framework of Anisotropic Chromodynamics, a non-perturbative
realization of QCD, we develop the Low-Nussinov picture of the Pomeron. In this
approach all the usual problems of low pT perturbative calculations (infrared
divergence) are naturally absent. Thus, we are able to perform an ab initio
calculation of the hadron-hadron total cross section. The result is a cross
section of the same magnitude as indicated experimentally and approximately
energy-independent (with a log^2 s growth). We further discuss the pT
dependence of the hadron-hadron elastic-scattering cross section, which
displays all the experimentally observed features.


title: Three-jet production at LEP and the bottom quark mass

abstract:
  We consider the possibility of extracting the bottom quark mass from LEP
data. The inclusive decay rate for $\zbb +\cdots$ is obtained at order $\as$ by
summing up the one-loop two-parton decay rate to the tree-level three-parton
rate. We calculate the decay width of the $Z$-boson into two and three jets
containing the $b$-quark including complete quark mass effects. In particular,
we give analytic results for a slight modification of the JADE clustering
algorithm. We also study the angular distribution with respect to the angle
formed between the gluon and the quark jets, which has a strong dependence on
the quark mass. The impact of higher order QCD corrections on these observables
is briefly discussed. Finally, we present numerical results for some popular
jet-clustering algorithms and show that, indeed, these three-jet observables
are very sensitive to the $b$-quark mass and well suited for its determination
at LEP.


title:
Reconciling Cold Dark Matter with COBE/IRAS Plus Solar and Atmospheric
  Neutrino Data

abstract:
  We present a model where an unstable MeV Majorana tau \neu can naturally
reconcile the cold dark matter model (CDM) with cosmological observations of
large and small scale density fluctuations and, simultaneously, with data on
solar and atmospheric neutrinos. The solar \neu deficit is explained through
long wavelength, so-called {\sl just-so} oscillations involving conversions of
\ne into both \nm and a sterile species \ns, while atmospheric \neu data are
explained through \nm to \ne conversions. Future long baseline \neu oscillation
experiments, as well as some reactor experiments will test this hypothesis. The
model is based on the spontaneous violation of a global lepton number symmetry
at the weak scale. This symmetry plays a key role in generating the
cosmologically required decay of the \nt with lifetime $\tau_{\nu_\tau} \sim
10^2 - 10^4$ seconds, as well as the masses and oscillations of the three light
\neus \ne, \nm and \ns required in order to account for solar and atmospheric
\neu data. It also leads to the invisibly decaying higgs signature that can be
searched at LEP and future particle colliders.


title: Tau Decays into Four Pions

abstract:
  We compute branching ratios and invariant mass distributions of the tau
decays into four pions. The hadronic matrix elements are obtained by starting
from the structure of the hadronic current in chiral limit and then
implementing low-lying resonances in the different channels. Reasonable
agreement with experiment is obtained both for the $\tau \to \nu_{\tau} + (4
\pi ) $ decay rates and the $e^+e^- \to (4 \pi ) $ cross sections. Furthermore
we supply an interface to use our matrix elements within the Tauola Monte-Carlo
program.


title:
Some Properties of a Transient New Coherent Condition of Matter Formed
  in High--Energy Hadronic Collisions

abstract:
  We investigate the dynamical possibility for the formation of a transient new
coherent condition of matter in high--energy hadronic collisions. The coherent
bosonic amplitude is characterized by a non--zero momentum and is sustained by
$P $--wave interactions of quasi--pions in a dense fermionic medium. We make
quantitative estimates of several essential properties: the condensate momentum
and the fermionic density, the size of the coherent amplitude and the negative
energy density contributed by the condensate, a characteristic proper time for
the system to exist prior to breakdown into a few pions, and a characteristic
extension of the system over the plane perpendicular to the collision axis.
These quantities then allow us to make definite estimates of new signals: a few
pions with anomalously small transverse momenta $\leq 50 $ MeV/c; and a
possible anomalous bremsstrahlung of very soft photons with characteristic
transverse momenta as low as about 4 MeV/c.


title: Astrophysical Limits on Gravitino Mass

abstract:
  We calculate exotic cooling rates of stars due to photo-production of light
particles (mostly scalars and pseudoscalars) which originate from the hidden
sector of no scale supergravity theories. Using this we can restrict the
gravitino mass $m_{3/2}$. The range of eliminated values of $m_{3/2}$ stretches
over six orders of magnitude and is given by $\displaystyle{2 \times 10^8 <
{m_{\tilde g} \over m_{3/2}} < 6 \times 10^{13}}$, $m_{\tilde g}$ being the
gluino mass. Combining our result with the earlier analysis from colliders
($\displaystyle{ {m_{\tilde g} \over m_{3/2}} < 2.7 \times 10^{14}}$) we
conclude that $\displaystyle{{m_{\tilde g} \over m_{3/2}} < {\cal O}(10^8)}$
except for a narrow window around $10^{14}$. Together with the current
experimental limit on $m_{\tilde{g}}$ and cosmological constraints on
$m_{3/2}$, albeit model dependent, our analysis shows that a light gravitino is
on the verge of being ruled out.


title: Elimination of the Landau Ghost from Chiral Solitons

abstract:
  We show a practical way based on the K\"{a}ll\'{e}n-Lehmann representation
for the two-point functions to eliminate the instability of the vacuum against
formation of small sized meson configurations in the chiral $\sigma$ model.


title: QCD Phase Transition in Hot Hadronic Matter

abstract:
  We analyse the QCD chiral phase transition in the nonlinear and linear
$\sigma$-model. The strategy is the same in both cases. We fix the parameters
of the effective meson theory at temperature $T=0$ and extrapolate the models
to temperatures in the vicinity of the phase transition. The linear
$\sigma$-model in $SU(3)\times SU(3)$ gives a crossover around $T_c\approx190$
MeV. Around this temperature chiral $SU(2)\times SU(2)$ is almost restored. We
also calculate meson masses as a function of temperature.


title:
Production of Polarized tau Pairs and Tests of CP Violation Using
  Polarized e+e- Colliders Near Threshold

abstract:
  We consider the production of tau pairs by electron-positron colliding beams
at the maximum cross section near the threshold. At this energy tau pairs are
produced mostly in the s-wave which implies that the spin of the tau pairs are
almost always pointing in the beam direction independent of the production
angle. When both electrons and positrons are longitudinally polarized in the
same direction, for example 90%, one can obtain tau pairs with 99% polarization
in the direction of the polarization vectors of the incident beams. Tests of CP
violation and study of the structure of weak interactions using such polarized
tau pairs are discussed.


title:
$WZ$ Production at Hadron Colliders: Effects of Non-Standard $WWZ$
  Couplings and QCD Corrections

abstract:
  The process $p\,\pbar \rightarrow W^{\pm}Z + X \rightarrow \ell^\pm_1 \nu_1
\ell_2^+ \ell_2^- + X$ is calculated to ${\cal O}(\alpha_s)$ for general $C$
and $P$ conserving $WWZ$ couplings. At the Tevatron center of mass energy, the
QCD corrections to $WZ$ production are modest. At Large Hadron Collider (LHC)
energies, the inclusive QCD corrections are large, but can be reduced
significantly if a jet veto is imposed. Sensitivity limits for the anomalous
$WWZ$ couplings are derived from the next-to-leading order $Z$ boson transverse
momentum distribution for Tevatron and LHC energies. Unless a jet veto is
imposed, next-to-leading order QCD corrections decrease the sensitivity to
anomalous $WWZ$ couplings considerably at LHC energies, but have little
influence at the Tevatron. We also study, at next-to-leading order, rapidity
correlations between the $W$ and $Z$ decay products, and the $ZZ/WZ$ and
$WZ/W\gamma$ cross section ratios. These quantities are found to be useful
tools in searching for the approximate zero present in the Standard Model $WZ$
helicity amplitudes. The prospects for observing the approximate amplitude zero
at the Tevatron and the LHC are critically assessed.


title: The heavy top quark in the two Higgs doublet model

abstract:
  Constraints on the two Higgs doublet model are presented, assuming a top mass
of 174 $\pm$ 17 GeV. We concentrate primarily on the ``type II'' model, where
up--type quarks receive their mass from one Higgs doublet, and down--type
quarks receive their mass from the second doublet. High energy constraints
derived from the $W$ mass, the full width of the $Z$ and the $b \bar b$ partial
width of the $Z$ are combined with low energy constraints from $\Gamma(b\to s
\gamma)$, $\Gamma(b \to c \tau \bar\nu_\tau)$ and $B^0$-$\bar B^0$ mixing to
determine the experimentally favored configurations of the model. This
combination of observables rules out small charged Higgs masses and small
values of $\tan\beta$, and provides some information about the neutral Higgs
masses and the mixing angle $\alpha$. In particular, constraints derived from
the $\rho$ parameter rule out configurations where the charged Higgs is much
heavier or much lighter than the neutral Higgses. We discuss a scenario where
$\Gamma(Z\to b \bar b)$ is enhanced relative to the standard model result,
which unfortunately is on the verge of being ruled out by the combination of
$\Gamma(b\to s \gamma)$ and $\rho$ parameter constraints. Implications for
various extensions of the standard model are briefly discussed.


title: QCD and Jet Physics

abstract:
  The current status of the QCD coupling constant $\alpha_S$ and experimental
and theoretical studies of hadronic jets are reviewed.


title:
Neutron Electric Dipole Moment under Non-Universal Soft SUSY Breaking
  Terms

abstract:
  The electric dipole moment of the neutron (EDMN) is re-examined in a general
framework of the soft supersymmetry breaking. We point out some features of the
relation between the EDMN and non-universal soft supersymmetry breaking terms.
We give the constraints on the soft scalar masses and the soft CP phases, which
have the rather large dependence on the non-universality of the soft breaking
terms. We also show that the soft CP phase $\phi_B$ which has no natural
suppression mechanism may not have large contribution to the EDMN in a certain
parameter region where the radiative symmetry breaking occurs successfully.
$\phi_B$ may not need to be so small.


title: Table of Running Quark Mass Values : 1994

abstract:
  Running quark mass values $m_q(\mu)$ at some typical energy scales ($\mu=1$
GeV, $\mu=m_W$, and so on) are reviewed. The values depend considerably on the
value of $\Lambda_{\overline{MS}}$, especially, the value of top quark mass at
$\mu=1$ GeV does so. The relative ratios of light quark masses ($m_u$, $m_d$
and $m_s$) to heavy quark masses ($m_c$, $m_b$ and $m_t$) are still
controversial.


title: Instanton-induced production of QCD jets

abstract:
  We consider the instanton contributions for the production of a gluon jet
with large transverse momentum in QCD. We find that Mueller's corrections
corresponding to the rescattering of hard quanta are likely to remove
contributions of large instantons, making this cross section well defined. This
observation generalizes the previous discussion of instanton effects in the
deep inelastic scattering and suggests that all hard processes in the QCD
receive hard non-perturbative corrections from instantons of small size, of
order $\rho\sim 1/(Q\alpha_s)$.


title:
Direct calculation of the triple-pomeron coupling for diffractive DIS
  and real photoproduction

abstract:
  We present a unified direct calculation of the triple-pomeron coupling
$A_{3\Pom}(Q^{2})$ for diffractive real photoproduction ($Q^{2}=0$) and deep
inelastic scattering at large $Q^{2}$ in the framework of the dipole approach
to the generalized BFKL pomeron. The small phenomenological value of
$A_{3\Pom}(0)\approx 0.16$\,GeV$^{2}$, which was a mystery, is related to the
small correlation radius $R_{c}\approx 0.3$\,fm for the perturbative gluons. We
confirm the early expectations of weak $Q^{2}$ dependence of the dimensionfull
coupling $A_{3\Pom}(Q^{2})$ and predict that it rises by the factor $\sim 1.6$
from real photoproduction to deep inelastic scattering.


title: Diffractive DIS from the generalized BFKL pomeron. Predictions for HERA

abstract:
  We present microscopic QCD calculation of the cross section of diffractive
DIS and of the partonic structure of the pomeron from the dipole approach to
the generalized BFKL pomeron. We show that the pomeron can not be treated as a
particle with uniquely defined structure function and flux in the proton. We
find strong factorization breaking which can approximately be described by the
two-component structure function of the pomeron, each component endowed with
the different flux of pomerons in the proton. We predict very weak $Q^{2}$
dependence of the diffractive contribution to the proton structure function.


title: A QCD Analysis of the Mass Structure of the Nucleon

abstract:
  {}From the deep-inelastic momentum sum rule and the trace anomaly of the
energy-momentum tensor, I derive a separation of the nucleon mass into the
contributions of the quark and gluon kinetic and potential energies, the quark
masses, and the trace anomaly.


title:
Radiative Corrections to the Higgs Boson Decay into a Longitudinal
  $W$-Boson Pair in a Two-Doublet Model

abstract:
  The decay rate of a (neutral) Higgs boson ($H$) going into a longitudinal
$W$-boson pair is calculated by including one loop radiative corrections in a
two-Higgs doublet model. It is assumed that the
  Higgs boson $H$ is much heavier than the $W$ boson and a full use has been
made of the equivalence theorem. A possibility is explored extensively that the
precise measurement of the decay rate of $H$ could be useful as a probe of the
other neutral as well as charged Higgs bosons through potentially important
radiative corrections. It is pointed out that, for some choice of the
parameters, the radiative corrections are sizable and that there exist a
possibility of extracting useful information on the other Higgs boson masses.


title:
Instability of a Nielsen-Olesen Vortex Embedded in the Electroweak
  Theory: I. the Single-Component Higgs Gauge

abstract:
  The stability of an abelian (Nielsen-Olesen) vortex embedded in the
electroweak theory against W production is investigated in a gauge defined by
the condition of a single-component Higgs field. The model is characterized by
the parameters $\beta=({M_H\over M_Z})^2$ and $\gamma=\cos^2\theta_{\rm w}$
where $\theta_{\rm w}$ is the weak mixing angle. It is shown that the equations
for W's in the background of the Nielsen-Olesen vortex have no solutions in the
linear approximation. A necessary condition for the nonlinear equations to have
a solution in the region of parameter space where the abelian vortex is
classically unstable is that the W's be produced in a state of angular momentum
$m$ such that $0>m>-2n$. The integer $n$ is defined by the phase of the Higgs
field, $\exp(in\varphi)$. Solutions for a set of values of the parameters
$\beta$ and $\gamma$ in this region were obtained numerically for the case
$-m=n=1$. The possibility of existence of a stationary state for $n=1$ with W's
in the state $m=-1$ was investigated. The boundary conditions for the
Euler-Lagrange equations required to make the energy finite cannot be satisfied
at $r=0$. For these values of $n$ and $m$ the possibility of a finite-energy
stationary state defined in terms of distributions is discussed.


title:
New physics motivated by the low energy approach to electric charge
  quantization

abstract:
  The low-energy approach to electric charge quantization predicts physics
beyond the minimal standard model. A model-independent approach via effective
Lagrangians is used examine the possible new physics, which may manifest itself
indirectly through family-lepton--number violating rare decays.


title:
Right Handed Weak Currents in Sum Rules for Axialvector Constant
  Renormalization

abstract:
  The recent experimental results on deep inelastic polarized lepton scattering
off proton, deuteron and $^{3}$He together with polari% zed neutron
$\beta$-decay data are analyzed. It is shown that the problem of Ellis-Jaffe
and Bjorken sum rules deficiency and the neutron paradox could be solved
simultaneously by assuming the small right handed current (RHC) admixture in
the weak interaction Lagrangian. The possible RHC impact on pion-nucleon
$\sigma$-term and Gamow-Teller sum rule for $(p,n)$ nuclear reactions is
pointed out.


title: Pomeron with a Running Coupling Constant: Intercept and Slope

abstract:
  The equation for two reggeized gluons with a running QCD coupling constant,
proposed earlier on the basis of the bootstrap condition, is investigated by
the variational technique in the vacuum channel. The pomeron intercept and
slope are calculated as a function of the infrared cutoff parameter $m$ ("the
gluon mass"). The intercept depends weakly on $m$ staying in the region
$0.3--0.5$ for values of $m$ in the range $0.3--1.0\ GeV$. The slope goes down
from $5.0\ GeV^{-2}$ to $0.08\ GeV^{-2}$ in this range. The optimal value of
$m$ seems to lie in the region $0.6--0.8\ GeV$ with the intercept $0.35$ and
slope $0.35--0.15$. The character of the pomeron singularity: pole or cut, is
also discussed.


title: $D^*D\pi$ and $B^*B\pi$ couplings in QCD

abstract:
  We calculate the $D^*D\pi$ and $B^*B\pi$ couplings using QCD sum rules on the
light-cone. In this approach, the large-distance dynamics is incorporated in a
set of pion wave functions. We take into account two-particle and
three-particle wave functions of twist 2, 3 and 4. The resulting values of the
coupling constants are $g_{D^*D\pi}= 12.5\pm 1$ and $g_{B^*B\pi}= 29\pm 3 $.
From this we predict the partial width $ \Gamma (D^{*+} \ra D^0 \pi^+ )=32 \pm
5~ keV $. We also discuss the soft-pion limit of the sum rules which is
equivalent to the external axial field approach employed in earlier
calculations. Furthermore, using $g_{B^*B\pi}$ and $g_{D^*D\pi}$ the pole
dominance model for the $ B \ra \pi$ and $D\ra \pi$ semileptonic form factors
is compared with the direct calculation of these form factors in the same
framework of light-cone sum rules.


title: Non-local Electroweak Baryogenesis Part I : Thin Wall Regime

abstract:
  We investigate `non-local' schemes for baryogenesis at a first order
electroweak phase transition, in which the effects of a $CP$ violating
condensate on the bubble wall propagate into the unbroken phase where the
sphaleron rate is unsupressed. Such a condensate exists in multi-Higgs
extensions of the standard model, and may exist due to an instability in the
minimal standard model. In this paper we first discuss the general problem of
determining the $CP$ violating perturbations, distinguishing two regimes
(quantum and classical). We then give an analytic treatment of quantum
mechanical reflection in the thin wall regime, in which interactions with the
plasma can be neglected as a particle propagates across the wall. We focus on
leptons because of their much weaker coupling to the plasma. We argue that they
are likely to be accurately described by this calculation, but quarks are not.
The relative magnitude of the baryon asymmetry produced for different fermions
depends on their relative Yukawa couplings ({\it not} their zero temperature
masses), their transport properties and their interactions. We calculate the
baryon asymmetry for various parameter ranges and conclude that asymmetries
comparable with observations can be generated.


title: Non-local Electroweak Baryogenesis Part II : The Classical Regime

abstract:
  We investigate baryogenesis at a first order electroweak phase transition in
the presence of a CP violating condensate on the bubble walls, in the regime in
which the bubble walls are `thick', in the sense that fermions interact with
the plasma many times as the bubble wall passes. Such a condensate is present
in multi-Higgs extensions of the standard model and may be formed via an
instability in the minimal standard model. We concentrate on particles with
typical thermal energies in the plasma, whose interactions with the wall are
accurately described by the WKB approximation, in which a classical chiral
force is evident. The deviations from thermal equilibrium produced by motion of
the wall are then treated using a classical Boltzmann equation which we solve
in a fluid approximation. From the resulting equations we find two effects
important for baryogenesis: (i) a classical chiral force term due to the $CP$
violating background, and (ii) a term arising from hypercharge violating
interactions which are pushed out of equilibrium by the background{field.
Provided the wall propagates slower than the speed of sound, both terms lead to
the diffusion of a chiral asymmetry in front of the wall. This can produce a
baryon asymmetry of the observed magnitude for typical wall velocities and
thicknesses.


title: Impact of R-Parity Violation on Supersymmetry Searches at the Tevatron

abstract:
  We evaluate cross sections for $\eslt$, 1$\ell$ and various dilepton and
multilepton event topologies that result from the simultaneous production of
all sparticles at the Tevatron collider, both within the minimal model
framework as well as in two different $R$-parity violating scenarios. Our
analysis assumes that these $R$-violating couplings are small, and that their
sole effect is to cause the lightest supersymmetric particle to decay inside
the detector. We reassess future strategies for sparticle searches at the
Tevatron, and quantify by how much the various signals for supersymmetry could
differ from their minimal model expectations, if $R$-parity is not conserved
due to either baryon number or lepton number violating operators. We also
evaluate the Tevatron reach in $m_{\tg}$ for the various models, and find that
rate-limited multilepton signals ultimately provide the largest reach for both
$R$-parity conserving and $R$-parity violating cases.


title: Probing Supergravity Models with Indirect Experimental Signatures

abstract:
  We explore the one-loop electroweak radiative corrections in the context of
the traditional minimal $SU(5)$ and the string-inspired $SU(5)\times U(1)$
supergravity models by calculating explicitly vacuum-polarization and
vertex-correction contributions to the $\epsilon_1$ and $\epsilon_b$
parameters. We also include in this analysis the constraint from $b\rightarrow
s\gamma$ whose inclusive branching ratio $B(b\rightarrow s\gamma)$ has been
actually measured very recently by CLEO. We find that by combining these three
most important indirect experimental signatures and using the most recent
experimental values for them, $m_t\gtrsim 170 {\rm GeV}$ is excluded for
$\mu>0$ in both the minimal $SU(5)$ supergravity and the no-scale $SU(5)\times
U(1)$ supergravity. We also find that $m_t\gtrsim 175(185) {\rm GeV}$ is
excluded for any sign of $\mu$ in the minimal ($SU(5)\times U(1)$) supergravity
model.


title: Supersymmetry

abstract:
  I review phenomenologically interesting aspects of supersymmetry. First I
point out that the discovery of the positron can be regarded as a historic
analogue to the would-be discovery of supersymmetry. Second I review the recent
topics on the unification of the gauge coupling constants, $m_b$--$m_\tau$
relation, proton decay, and baryogenesis. I also briefly discuss the recent
proposals to solve the problem of flavor changing neutral currents. Finally I
argue that the measurements of supersymmetry parameters may probe the physics
at the Planck scale.


title: Chiral Symmetry Breaking in Quenched Massive Strong-Coupling QED$_4$

abstract:
  We present results from a study of subtractive renormalization of the fermion
propagator Dyson-Schwinger equation (DSE) in massive strong-coupling quenched
QED$_4$. Results are compared for three different fermion-photon proper vertex
{\it Ans\"{a}tze\/}: bare $\gamma^\mu$, minimal Ball-Chiu, and
Curtis-Pennington. The procedure is straightforward to implement and
numerically stable. This is the first study in which this technique is used and
it should prove useful in future DSE studies, whenever renormalization is
required in numerical work.


title: Perturbative QCD

abstract:
  This is the written version of a set of lectures on perturbative QCD that
were delivered to a mixed audience of young theorists and experimentalists in
the course of the XXII International Meeting on Fundamental Physics. These
notes are virtually a verbatim transcription of the lectures. The selection of
topics is somewhat arbitrary, but two basic points are emphasized: the
rationale behind QCD and how ongoing experiments, such as those taking place in
LEP and HERA, contribute to our understanding of strong interactions. The
lectures are thus roughly divided into three parts: foundations of QCD,
determination of $\alpha_s$ and jet physics, and deep inelastic experiments.


title: Studying Structure of Electroweak Corrections

abstract:
  Several different effects in electroweak quantum corrections are explored
separately through the latest data on the weak-boson masses. The leading-log
approximation, the improved-Born approximation and the non-decoupling top-quark
effects are studied without depending on the recent CDF data of $m_t$, and the
results are given in a form independent of the Higgs mass. On the other hand,
the bosonic- and the non-decoupling Higgs effects are examined by fully taking
account of those CDF data. It is emphasized that future precision measurements
of $M_W$ and $m_t$ are considerably significant not only for further studies of
the electroweak theory at higher confidence level but also for new physics
searches beyond it.


title: Towards a Model Independent Analysis of Rare $B$ Decays

abstract:
  We propose to undertake a model-independent analysis of the inclusive decay
rates and distributions in the processes \bgamaxs~ and \Bsell ~($B=B^\pm$ or
$B^0_d$). We show how measurements of the decay rates and distributions in
these processes would allow us to extract the magnitude and sign of the
dominant Wilson coefficients of the magnetic moment operator $\mb \bar{s}_L
\sigma_{\mu \nu} b_R F^{\mu \nu }$ and the four-fermion operators $(\bar{s}_L
\gamma_\mu b_L)(\bar{\ell} \gamma^{\mu} \ell)$ and $(\bar{s}_L \gamma_\mu
b_L)(\bar{\ell} \gamma^{\mu}\gamma^5 \ell)$.


title:
The Structure of a Source from Interferometry Measurements in Heavy Ion
  Collisions

abstract:
  Some experimental results of correlation functions in Bose-Einstein
interferometry measurements exhibit a non smooth behaviour - oscillations.
Possible origin of such a behaviour in non-trivial spatial distribution of the
source is considered. A method for obtaining additional information about the
structure of source emitting identical particles is suggested. It is shown that
this information could be extracted by a one dimensional fourier analysis of
the filtered correlation function. Further possible enhancement of the method
is sketched. Some technical aspects of the proposed technique are discussed.


title: Taming the Scalar Mass Problem with a Singlet Higgs Boson

abstract:
  We investigate the fine-tuning problem in the Standard Model and show that
Higgs boson and top quark masses consistent with current experimental bounds
cannot be obtained unless one extends the particle spectrum. A minimal
extension which achieves this involves addition of a singlet real scalar and
one generation of vectorlike fermions. We show that this leads to a
phenomenologically viable prediction for the mass of the Standard Model Higgs
boson.


title:
What does the CCFR measurement of the Gross--Llewelyn Smith sum rule
  tell us?

abstract:
  Recently the CCFR Collaboration reported the measurement of the
Gross--Llewellyn Smith sum rule %at $Q^2=3\; \mr{GeV}^2$:
$\int^{1}_{0}\mr{d}F_{3}^{\nu p+\bare{\nu}p}(x,Q^2=3\;\mr{GeV}^2)= 2.50\pm
0.018(\mr{stat})$. Subsequently Kataev and Sidorov analyzed the
$Q^2$--dependence of this sum rule and pointed out a discrepancy between the
results obtained via integration of the NLO fits to $xF_{3}(x,Q^2)$ and the
purely perturbative prediction. We suggest an explanation of this disagreement
and show that the result of the CCFR measurement of the GLS sum rule integral
can be determined from the knowledge of the value of $\Lambda_{\bbare{MS}}$
only.


title: Calculation of 1/m^3 terms in the total semileptonic width of D mesons.

abstract:
  We calculate the 1/$m^3_c$ corrections in the inclusive semileptonic widths
of $D$ mesons. We show that these are due to the novel penguin type operators
that appear at this level in the transition operator. Taking into account the
nonperturbative corrections leads to the predicted value of the semileptonic
width significantly lower than the experimental value. The $1/m^3_c$ worsen the
situation or at the very least, within uncertainty, give small contribution. We
indicate possible ways out. It seems most probable that violations of duality
are noticeable in the energy range characteristic to the inclusive decays in
the charm family. Theoretically these deviations are related to divergence of
the high-order terms in the power expansion in the inverse heavy quark mass.


title: The Electroweak Phase Transition, Part 1: Review of Perturbative Methods

abstract:
  Talk presented at the conference Quarks `94: Vladimir, Russia. I review the
successes and limitations of standard perturbative methods for studying the
order and strength of the electroweak phase transition.


title: The Electroweak Phase Transition, Part 2: $\epsilon$-Expansion Results

abstract:
  Talk presented at the conference Quarks `94: Vladimir, Russia. I summarize
the application of $\epsilon$-expansion methods to the electroweak phase
transition. Results from both leading and next-to-leading order calculations
are discussed.


title: Estimating Condensates from the Difference of Tau Branching Fractions

abstract:
  The difference of tau partial decay widths into even and odd number of pions
may be considered as another important constraint on the hadronic spectral
function, in addition to four classic sum rules of current algebra. Within
certain reasonable assumptions its value may be used to test the factorization
hypothesis and estimate the contribution of dimension 6 condensates into the
tau hadronic decay width.


title: The Isgur-Wise function in a relativistic model for $q\bar Q$ system

abstract:
  We use the Dirac equation with a ``(asymptotically free) Coulomb + (Lorentz
scalar) linear '' potential to estimate the light quark wavefunction for $
q\bar Q$ mesons in the limit $m_Q\to \infty$. We use these wavefunctions to
calculate the Isgur-Wise function $\xi (v.v^\prime )$ for orbital and radial
ground states in the phenomenologically interesting range $1\leq v.v^ \prime
\leq 4$. We find a simple expression for the zero-recoil slope, $\xi^ \prime
(1) =-1/2- \epsilon^2 <{r_q}^2>/3$, where $\epsilon$ is the energy eigenvalue
of the light quark, which can be identified with the $\bar\Lambda $ parameter
of the Heavy Quark Effective Theory. This result implies an upper bound of
$-1/2$ for the slope $\xi^\prime (1)$. Also, because for a very light quark $q
(q=u, d)$ the size $\sqrt {<{r_q}^2>}$ of the meson is determined mainly by the
``confining'' term in the potential $(\gamma_\circ \sigma r)$, the shape of
$\xi_{u,d}(v.v^\prime )$ is seen to be mostly sensitive to the dimensionless
ratio $\bar \Lambda_{u,d}^2/\sigma$. We present results for the ranges of
parameters $150 MeV <\bar \Lambda_{u,d} <600 MeV$ $(\bar\Lambda_s \approx
\bar\Lambda_{u,d}+100 MeV)$, $0.14 {GeV}^2 \leq \sigma \leq 0.25 {GeV}^2$ and
light quark masses $m_u, m_d \approx 0, m_s=175 MeV$ and compare to existing
experimental data and other theoretical estimates. Fits to the data give:
${\bar\Lambda_{u,d}}^2/\sigma =4.8\pm 1.7 $, $-\xi^\prime_{u,d}(1)=2.4\pm 0.7$
and $\vert V_{cb} \vert \sqrt {\frac {\tau_B}{1.48 ps}}=0.050\pm 0.008$ [ARGUS
'93]; ${\bar\Lambda_{u,d}}^2/\sigma = 3.4\pm 1.8$, $-\xi^\prime_{u,d}(1)=1.8\pm
0.7$ and $\vert V_{cb} \vert \sqrt { \frac {\tau_B}{1.48 ps}}=0.043\pm 0.008$
[CLEO '93]; ${\bar\Lambda_{u,d}}^2/


title: A Detailed Analysis of a Modified Fritzsch Scheme of Quark Mass Matrices

abstract:
  We investigate in detail a modified version of the Fritzsch scheme where the
diagonal entries $(M_{u,d})_{22}$ are introduced as free parameters instead of
being zero. We find that $(M_u)_{22}$ and $(M_d)_{22}$ are restricted to l in
the range $m_u-m_c\leq (M_u)_{22}< m_t-m_c$ and $m_d-m_s\leq (M_d)_{22}<
m_b-m_s$. In the context of this scheme, we obtain the ratio ${|V_{td}|\over
|V_{ts}|}\approx\sqrt{{m_d\over m_s}}$ under quite general conditions whereas
the ratio ${|V_{ub}|\over |V_{cb}|}$ is sensitive to the values of $(M_u)_{22}$
and $(M_d)_{22}$. The two independent phases are found to take rather preferred
values.


title:
Recent Progress in the Theory of Heavy Quark and Quarkonium Production
  in Hadronic Collisions

abstract:
  We review heavy quark and quarkonium production in high energy hadronic
collisions. We discuss the status of the theoretical calculations and their
uncertainties. We then compare the current theoretical results with the most
recent measurements from the tevatron collider experiments.


title:
$B \rightarrow X_s\,\gamma$ and $B \rightarrow K^*\,\gamma$ in the
  standard and 2H models

abstract:
  Theoretical predictions for the branching ratios of the $B \rightarrow
X_s\,\gamma$ and $B \rightarrow K^*\,\gamma$ decays are calculated in the
Standard Model and in the (type II) two-Higgs-doublet model. Both the complete
leading and the partially known next-to-leading order QCD corrections are
included. The uncertainties due to the regularization scheme dependence
introduced by the incomplete NLO terms are discussed. The results are compared
with the recent CLEO II measurements and a new lower limit on the charged Higgs
boson mass, $M_{H^\pm} > \sim 200$ GeV, is obtained.


title: Next-to-leading prediction of $\epse$: an upgraded analysis

abstract:
  We present an updated theoretical prediction of $\epse$, using the
next-to-leading $\DSone$ effective hamiltonian and lattice QCD matrix elements.
The CP violating phase is costrained by using both the experimental values of
$\ep$ and $x_d$, assuming the theoretical determination of $f_B$. Predictions
of $\cos\delta$ and $\sin 2\beta$ are also obtained in this way. For $\epse$,
our estimate is $\epse=(2.8 \pm 2.4)\times 10^{-4}$.}


title:
Consistency of the Chiral Pion-Pion Scattering Amplitudes with Axiomatic
  Constraints

abstract:
  The pion-pion scattering amplitudes provided by second-order chiral
perturbation theory are confronted with known rigorous constraints derived from
the axioms of quantum field theory. We mainly test constraints restricting the
$\pi^0$-$\pi^0$ $S$- and $D$-wave amplitudes in the unphysical interval $0\leq
s\leq 4m_\pi^2$. These constraints impose significant lower bounds for a linear
combination of coupling constants specifying the second order chiral
Lagrangian. The accepted value of this combination is consistent with these
bounds. The $\pi^0$-$\pi^0$ $S$- and $D$-waves are strongly correlated by a set
of constraints.


title:
Energy dependence of source geometry and chaoticity in hadronic
  collisions from Bose-Einstein correlations

abstract:
  We compare and analyse Bose-Einstein correlation data for $\pi^+ p$ and $K^+
p$ collisions at $\sqrt{s}=22\ GeV$ obtained by the NA22-Collaboration and data
for $p\bar{p}$ collisions at $\sqrt{s}=630\ GeV$ obtained by the
UA1-Minimum-Bias-Collaboration. Using a parametrization for a longitudinally
expanding source, we observe that correlation lengths and radii extracted from
fits to the data change significantly if one goes from the NA22- to the
UA1-data: the transverse radius of the chaotic source increases by about $50\%$
while the correlation lengths in longitudinal and transverse directions
decrease by about $50\%$ and $30\%$, respectively. The chaoticity parameter
remains approximately constant or increases. DMR-THEP-94-6/W


title: Meson-Photon Transition Form Factors

abstract:
  We report results on the $\pi$-$\gamma$ transition form factor obtained
within the hard scattering approach including transverse momentum effects and
Sudakov corrections. The results clearly favor distribution amplitudes close to
the asymptotic form, $\sim x_1x_2$, and disfavor distribution amplitudes which
are strongly concentrated in the end-point regions. This observation is backed
by information on the elastic form factor of the pion and on its valence quark
distribution function. Applications of our approach to the $\eta$-$\gamma$ and
$\eta^\prime$-$\gamma$ transition form factors are discussed as well. Combining
the form factor data with the two-photon decay widths, we determine the $\eta$
and the $\eta^\prime$ decay constants and the $\eta$-$\eta^\prime$ mixing
angle.


title: Multiparticle Production and Statistical Analogies

abstract:
  The study of the singularities and zeros of the generating functions of
multiplicity distributions is advocated. Some hints from well known probability
distributions and experimental data are given. The statistical mechanics
analogies provoke to look for a signature of phase transitions. The program of
further experimental studies of the singularities is formulated.


title: Partons and Black Holes

abstract:
  A light-front renormalization group analysis is applied to study matter which
falls into massive black holes, and the related problem of matter with
transplankian energies. One finds that the rate of matter spreading over the
black hole's horizon unexpectedly saturates the causality bound. This is
related to the transverse growth behavior of transplankian particles as their
longitudinal momentum increases. This growth behavior suggests a natural
mechanism to impliment 'tHooft's scenario that the universe is an image of data
stored on a 2 + 1 dimensional hologram-like projection.


title: Effects of Top Compositeness

abstract:
  We investigate the effects of top quark compositeness on various physical
parameters, and obtain lower limits on the compositeness scale from electroweak
precision data. We consider corrections to top quark decay rates and other
physical processes. Our results depend sensitively on whether the left-handed
top is composite. A considerable enhancement of $t \bar t$ production is
possible if only the right-handed top is composite.


title: Radiative QCD Corrections: A Personal Outlook

abstract:
  We describe several problems related to the studies of the effects of
radiative QCD corrections in the phenomenological and theoretical
considerations thus summarizing the work of the QCD part of the Symposium on
"Radiative Corrections: Status and Outlook".


title:
Hard photon production rate of a quark-gluon plasma at finite quark
  chemical potential

abstract:
  We compute the photon production rate of a quark-gluon plasma (QGP) at finite
quark chemical potential $\mu $ using the Braaten-Pisarski method, thus
continuing the work of Kapusta, Lichard, and Seibert who did the calculation
for $\mu =0$.


title:
Supersymmetric Electroweak Renormalization of the Z-Width in the MSSM
  (I)

abstract:
  Within the framework of the MSSM, we compute the complete set of electroweak
one-loop supersymmetric quantum effects on the width $\Gamma_Z$ of the
$Z$-boson in the on-shell renormalization scheme. Numerical analyses of the
corrections to the various partial widths into leptons and quarks are
presented. On general grounds, the average size of the electroweak SUSY
corrections to $\Gamma_Z$ may well saturate the level of the present
theoretical uncertainties, even if considering the full supersymmetric spectrum
lying in the neighbourhood of the unaccessible LEP 200 range. Remarkably
enough, for the present values of the top quark mass, the electroweak SUSY
effects could be, globally, very close or even bigger than the electroweak SM
corrections, but opposite in sign. Therefore, in the absence of theoretical
errors, there are large regions of parameter space where one could find that,
effectively, the electroweak SM corrections are ``missing'', or even having the
``wrong'' sign. This should be helpful in discriminating between the SM and the
MSSM. However, an accurate prediction of the electroweak quantum effects on
$\Gamma_Z$ will only be possible, if $\Delta r$ and $\alpha_s$ are pinned down
in the future with enough precision.


title:
Supersymmetric Electroweak Renormaliztion of the Z-Width in the MSSM
  (II)

abstract:
  We address the computation of \Gamma_Z and of the intriguing quantity R_b in
the MSSM including full treatment of the Higgs sector. For a pseudoscalar Higgs
mass m_{A^0}>70\,GeV and CDF limits on m_t, the bounds on R_b at 1\sigma level
leave no room to the MSSM to solve the `R_b crisis' for any combination of the
parameters, not even admitting the possibility of a light chargino and a light
stop of O(50) GeV; however, for m_t not restricted by CDF, a `tangential'
solution exists in the window 2<\tan\beta<10 with a light chargino and stop. In
contrast, for a pseudoscalar mass 40\,GeV<m_{A^0}<60\,GeV and CDF limits on
m_t, the `R_b crisis' can be solved in a comfortable way, for any SUSY spectrum
above the phenomenological bounds, provided \tan\beta>m_t/m_b. Our general
conclusion is that, if there is a `R_b crisis' at all, its solution within the
MSSM has to do more with the peculiar structure of the SUSY Higgs sector rather
than with the spectrum of genuine supersymmetric particles. In view of the
range predicted for m_{A^0}, LEP 200 should be able to definitely settle down
this question.


title: Possible Puzzles in Nonleptonic B Decays

abstract:
  I discuss the recent controversy over the semileptonic branching ratio of the
$B$ meson, pointing out that it is only the combination of this quantity with
the reported charm multiplicity in $B$ decays which is in serious conflict with
theoretical calculations. I consider possible solutions to the problem.
(Invited talk presented at the Eighteenth Johns Hopkins Workshop on Current
Problems in Particle Theory, Florence, Italy, August 31--September 2, 1994.)


title: A Model of Mesons based on $\chi$SB in the Light-Front Frame

abstract:
  Spontaneous breaking of chiral symmetry is discussed in the light-cone
framework. The essential ingredient is an infinite number of constituents near
zero light-cone momentum. These high (light-cone) energy degrees of freedom
freeze out and leave behind some explicit symmetry breaking in the low
(light-cone) energy effective Hamiltonian. Connections with Regge theory and
soft pion theorems are discussed. Taking the order parameter to be the 4-th
component of a chiral 4-vector, the effect of the spontaneous symmetry breaking
on meson masses and decay width is calculated and compared with experimental
data.


title: The Charm Physics Potential of a Tau-Charm Factory

abstract:
  The charm physics program accessible to a Tau-Charm Factory is summarized.
Semileptonic, leptonic, hadronic, rare and forbidden charm decay modes are
discussed, as well as \dmix\ mixing and CP violation in the charm sector. The
theoretical expectations in the Standard Model and beyond as well as the
experimental capabilities of a Tau-Charm Factory are examined for each of the
above processes. {To appear in {\it The Tau-Charm Factory in the Era of
B-Factories and CESR}, Stanford, CA, August 15-16, 1994}


title: Confinement, Crossing Symmetry, and Glueballs

abstract:
  We suggest that the quark-confining force is related by crossing symmetry to
a color-singlet glueball ${\cal G}$ which is well described as a loop of one
quantum of color magnetic flux. Electron pair annihilation as high as $\approx
2 GeV$ above the $\Upsilon$ mass could produce $\Upsilon \rightarrow
\ell^+\ell^-$ accompanied by ${\cal G}$ or one of its excited states.


title:
What one can learn about the QCD parton cascades studying the
  multiplicity distributions at HERA ?

abstract:
  New properties of the multiplicity distributions predicted by higher order
QCD and their physical origin are discussed briefly. Several studies which can
be performed at HERA are proposed.


title: The direct calculation of the slope of the QCD pomeron's trajectory

abstract:
  We demonstrate that the diffraction slope of the generalized BFKL pomeron
amplitude has the conventional Regge growth $B(s) = B(0) +
2\alpha_{\Pom}'\log(s)$. This proves that the generalized BFKL pomeron is
described by the moving $j$-plane singularity. We give an estimate for the
slope $\alpha_{\Pom}'$ in terms of the correlation radius for the perturbative
gluons.


title:
Ioffe-time distributions instead of parton momentum distributions in
  description of deep inelastic scattering

abstract:
  We argue that parton distributions in coordinate space provide a more natural
object for nonperturbative methods compared to the usual momentum distributions
in which the physics of different longitudinal distances is being mixed. To
illustrate the advantages of the coordinate space formulation, we calculate the
coordinate space distributions for valence quarks in the proton using the QCD
sum rule approach. A remarkable agreement is found between the calculated and
the experimentally measured u-quark distribution up to light-cone distances
$\Delta^- = \Delta^0 - \Delta^3$ of order $\sim 1$ fm in the proton rest frame.
The calculation for valence d quarks gives much worse results; the reasons for
this discrepancy are discussed.


title:
Two-Loop $ O(\alpha_sG_Fm_t^2)$ Correction to the $H\to b\bar b$ Decay
  Rate

abstract:
  We present the two-loop ${\cal O}(\alpha_sG_Fm_t^2)$ correction to the $b\bar
b$ decay rate of the Stan\-dard-Model Higgs boson, assuming that the $t$ quark
is much heavier than the Higgs boson. Apart from the universal correction
connected with the renormalizations of the wave function and the vacuum
expectation value of the Higgs field, this involves vertex corrections specific
to the presence of beauty in the final state. We calculate the latter by means
of a low-energy theorem. All would-be mass singularities related to the $b$
quark can be absorbed into the running Higgs-bottom Yukawa coupling. It turns
out that the total ${\cal O}(\alpha_sG_Fm_t^2)$ correction screens the leading
high-$m_t$ behaviour of the one-loop result by 71\% to 75\% for $M_H$ between
60~GeV and $2M_W$.


title: Particle Conjugation and the $1/N_C$ Corrections to $g_A$

abstract:
  We impose the requirement that the isovector axial vector current for the
soliton sector of the chiral quark model transforms correctly under particle
conjugation. This forces us to choose an otherwise arbitrary ordering of
collective space operators in such a way that the next--to--leading $1/N_C$
correction to $g_A$ vanishes.


title:
Resolving Ordering Ambiguities in the Collective Quantization by
  Particle Conjugation Constraints

abstract:
  We formulate the particle conjugation operation and its convenient
realization as $G$--parity in the framework of several chiral soliton models.
The Skyrme model, the Skyrme model with vector mesons and the chiral quark
model are specifically treated. The vector and axial vector currents are
classified according to their behavior under $G$--parity. In the soliton sector
particle conjugation constrains {\it a priori} ambiguous orderings of operators
in the space of the collective coordinates. In the Skyrme model with vector
mesons and in a local chiral model with an explicit valence quark this
classification scheme provides consistency conditions for the ordering of the
collective operators appearing in the $1/N_C$ corrections to the nucleon axial
charge and the isovector magnetic moment. These consistency conditions cause
the corrections obtained from an ordinary perturbation expansion to vanish in
the context of the collective quantization of the static soliton configuration.
This conclusion presumably applies to all local effective chiral models.


title: Reconciling the LEP and Slac Measurements of Sin^2(\Theta_W)

abstract:
  We consider whether a discrepancy between the SLAC and LEP measurements of
$\Sw$ can be explained by new physics. We find that only the contribution of a
new neutral gauge boson, $Z^\prime$, nearly degenerate with the Z can affect
the SLAC measurement while leaving the LEP observables almost unaffected. We
briefly discuss possible signals for this new gauge boson, including changes in
the $Z$ lineshape when measured with polarised electrons, small changes in
$R_b$, $A^e_{FB}$, and larger changes in two jet and $t\bar{t}$ production at
hadron colliders.


title:
Gluonic Excitations in Heavy Mesons and their Decay by Flux-Tube
  Breaking

abstract:
  We have examined decays of low-lying gluonic excitations of mesons (hybrids)
by chromoelectric flux-tube breaking. An analytical calculation of
non-relativistic flux-tube model decay amplitudes is performed in an harmonic
oscillator approximation. Specific decay signatures of all $J^{PC}$ charmonium
hybrids are identified and the widths predicted. We introduce a new selection
rule which can be used to understand the systematics of numerical decay
calculations.


title: What can a relativistic quark model tell us about charmed mesons?

abstract:
  A relativistic quark model is extended to incorporate chiral and gauge
symmetries. We obtain the DD*pi and DD*gamma couplings and find that the ratio
Gamma(D*0->D0pi0)/Gamma(D*0->D0gamma) constrains the charm-quark mass close to
1.45 GeV. Large 1/mc corrections appear in the heavy-quark contribution to the
DD*gamma coupling. The model is extended further to describe seven excited D
meson states. We find that semileptonic B decays into the ground and excited D
meson states do not account for the total semileptonic decay width of the B0.
The nonresonant contributions to the processes B0->D(*)pi+ell+nu appear to be
large enough to account for the discrepancy.


title:
Quantum Defects and the Long-Term Behavior of Radial Rydberg Wave
  Packets

abstract:
  We show that a theoretical description of radial Rydberg wave packets in
alkali-metal atoms based solely on hydrogenic wave functions and energies is
insufficient to explain data that could be obtained in pump-probe experiments
with current technology. The modifications to long-term revival times induced
by quantum defects cannot be obtained by direct scaling of the hydrogenic
results. Moreover, the effects of laser detuning and quantum defects are
different. An alternative approach providing analytical predictions using
supersymmetry-based quantum-defect theory is presented.


title: Mass Matrix Textures From Superstring Inspired SO(10) Models

abstract:
  We give a general prescription for deriving quark and lepton mass matrices
with ``texture'' zeros in the framework of superstring inspired $SO(10)$
models. The key to our approach is a new way to naturally implement the
doublet--triplet splitting which enables us to obtain symmetric quark and
lepton mass matrices which have different structures in the up and the down
quark sectors. We illustrate our method by deriving the Georgi--Jarlskog
texture which has six predictions in the flavor sector, and then show how it
generalizes to other symmetric texture models.


title: Semi-Exclusive Pion Production in Deep-Inelastic Scattering

abstract:
  We calculate azimuthal asymmetries and the Callan-Gross $R$-ratio for
semi-exclusive pion production in deep inelastic scattering taking into account
higher twist effects. Our results are qualitatively different from the
QCD-improved parton model predictions for semi-inclusive deep inelastic
scattering.


title: Searching for the Quark-Gluon Plasma

abstract:
  The claims for production of high energy densities and possible new states of
matter in collisions of nuclei by George F. Bertsch (Science, {\bf 265} (1994)
480-481) are examined and compared with simple explanations of the data which
have appeared in the literature.


title: Back-reaction in a cylinder

abstract:
  A system is studied in which initially a strong classical electric field
exists within an infinitely-long cylinder and no charges are present.
Subsequently, within the cylinder, pairs of charged particles tunnel out from
the vacuum and the current produced through their acceleration by the field
acts back on the field, setting up plasma oscillations. This yields a rough
model of phenomena that may occur in the pre-equilibrium formation phase of a
quark-gluon plasma. In an infinite volume, this back-reaction has been studied
in a field-theory description, and it has been found that the results of a full
calculation of this sort are well represented in a much simpler transport
formalism. It is the purpose here to explore that comparison for a situation
involving a cylindrical volume of given radius.


title: Status of Higher-Order Corrections in the Standard Electroweak Theory

abstract:
  We review recent theoretical progress in the computation of radiative
corrections beyond one loop within the standard model of electroweak
interactions, both in the gauge and Higgs sectors. In the gauge sector, we
discuss universal corrections of $\O(G_F^2M_H^2M_W^2)$, $\O(G_F^2m_t^4)$,
$\O(\alpha_sG_FM_W^2)$, $\O(\alpha_s^2G_Fm_t^2)$, and those due to virtual
$t\bar t$ threshold effects, as well as specific corrections to
$\Gamma\left(Z\to b\bar b\right)$ of $\O(G_F^2m_t^4)$, $\O(\alpha_sG_Fm_t^2)$,
and $\O(\alpha_s^3)$ including finite-$m_b$ effects. We also present an update
of the hadronic contributions to $\Delta\alpha$. Theoretical uncertainties,
other than those due to the lack of knowledge of $M_H$ and $m_t$, are
estimated. In the Higgs sector, we report on the $\O(\alpha_sG_Fm_t^2)$
corrections to $\Gamma\left(H\to f\bar f\,\right)$ including those which are
specific for the $b\bar b$ mode, the $\O(\alpha_s^2)$ corrections to
$\Gamma\left(H\to q\bar q\right)$ including the finite-$m_q$ terms, and the
$\O(\alpha_s)$ corrections to $\Gamma(H\to gg)$.


title: Signatures of Virtual LSPs at the Tevatron

abstract:
  Relatively light sneutrinos which are experimentally allowed and are not
theoretically disfavoured may significantly affect the currently popular search
strategies for supersymmetric particles by decaying dominantly into an
invisible channel. In certain cases the second lightest neutralino may also
decay invisibly leading to two extra carriers of missing energy (in addition to
the lightest supersymmetric particle (LSP) ) - the virtual LSPs (VLSPs). The
lighter charginos which would be produced in pairs with reasonably large
cross-sections at TEVATRON energies, decay dominantly into the hadronically
quiet lepton + sneutrino ($\not{E_T}$ ) modes with large branching ratios
leading to interesting unlike sign dilepton events which are not swamped by the
standard model background. The kinematical cuts required to eliminate the
backgrounds from WW, Drell-Yan and $\tau$ pair production are discussed in
detail. With 100 $pb^{-1}$ luminosity 10 - 35 background free events can be
found in a large region of the SUSY parameter space.


title: On the new method of computing two-loop massive diagrams

abstract:
  A recently proposed method of calculating scalar two-loop propagator and
vertex functions with massive particles is illustrated with simple examples. A
double integral representation is derived with the example of a propagator
function. An analogous representation is used to compute the vertex function
for space-like external momenta. Ways of dealing with divergent diagrams and of
controlling the accuracy of the numerical evaluation of the two-loop functions
are also discussed.


title: Heavy Quarkonium Effective Theory

abstract:
  We formulate a QCD-based effective theory approach to heavy quarkonia-like
systems as $\bar{c} c$ and $\bar{b} b$ resonances and $B_c$ states. We apply
the method to inclusive decays, working out a few examples in detail.


title:
QCD Corrections to Inclusive Distributions of Leptons in Decays of
  Polarised Heavy Quarks

abstract:
  Compact analytic expressions have been obtained for the first order
perturbative QCD corrections to the inclusive spectra of the leptons in the
semileptonic decays of polarised heavy quarks. Charmed and beautiful $\Lambda$
baryons from $Z^0$ decays can be viewed as sources of highly polarised charm
and bottom quarks. Charged leptons and neutrinos from $\Lambda_b$ and
$\Lambda_c$ decays can be used in the polarisation studies for the
corresponding heavy quarks. Thus our results are applicable for the b quark
polarisation measurements at LEP. Short lifetime enables polarisation studies
for the top quark. The angular-energy spectra of the charged leptons are
particularly useful in this respect whereas the distributions of the neutrinos
are sensitive to deviations from the V-A structure of the charged weak current
in the decay.


title: Spin Dependent Structure Functions of Nucleons and Nuclei

abstract:
  We review recent progress in the understanding of the spin structure of the
nucleon. For the free nucleon the issues addressed include the status of the
Bjorken and Ellis-Jaffe sum-rules and the role of the axial anomaly. We outline
recent work connecting the quark models familiar from hadron spectroscopy to
the spin and flavour dependence of the parton distributions. Finally we review
the current understanding of nuclear spin structure functions and particularly
the extraction of the neutron spin structure function from deuteron data.


title: Neutrinos interacting with Polarizable Media

abstract:
  We study Cherenkov and transition radiation of neutral spin 1/2 particles
which carry magnetic moments or electric dipole moments. In particular, we
estimate the radiation caused by the solar neutrino flux in dielectric media.


title:
Probing Quark Fragmentation Functions for Spin-1/2 Baryon Production in
  Unpolarized $e^+e^-$ Annihilation

abstract:
  We study the measurement of the quark fragmentation functions for spin-1/2
baryon production ($\Lambda$ and $\bar \Lambda$, in particular) in unpolarized
$e^+e^-$ annihilation. The spin-dependent fragmentation functions $\hat g_1(z)$
and $\hat h_1(z)$ can be probed in the process as a result of quark-antiquark
spin correlation and the weak decay of the baryons. The relevant cross section
is expressed as a product of the two-jet cross-section, the fragmentation
functions, and the differential width of the hyperon decay.


title:
Application of the Background-Field Method to the electroweak Standard
  Model

abstract:
  Application of the background-field method yields a gauge-invariant effective
action for the electroweak Standard Model, from which simple QED-like Ward
identities are derived. As a consequence of these Ward identities, the
background-field Green functions are shown to possess very desirable
theoretical properties. The renormalization of the Standard Model in the
background-field formalism is studied. A consistent on-shell renormalization
procedure retaining the full gauge symmetry is presented. The structure of the
counterterms is shown to greatly simplify compared to the conventional
formalism. A complete list of Feynman rules for the Standard Model in the
background-field method is given for arbitrary values of a quantum gauge
parameter including all counterterms necessary for one-loop calculations.


title: Transverse Lepton Polarization in Polarized W Decays

abstract:
  Calculations of transverse polarization of leptons in the decay $W\rightarrow
l\nu$ with polarized $W$'s are presented. Planned accelerators will produce
enough $W$'s for observation of the Standard Model contributions to this
polarization. One loop corrections to the polarization are given; these are too
small to be seen at presently available $W$ sources. The exchange of Majorons
will contribute to these polarizations; these may provide limits on the
couplings of these particles to leptons.


title: Properties of Factorial Cumulant to Factorial Moment Ratio

abstract:
  It is shown that the ratio of factorial cumulant moments to factorial moments
for a multiplicity distribution truncated in the tail reveals oscillations in
sign similar to those observed in experimental data. It is suggested that this
effect be taken into account in the analysis of data in order to obtain correct
physical information on the multiplicity distributions.


title:
Transverse Momentum Distributions in Large-rapidity Dijet Production at
  the Tevatron

abstract:
  In this contribution we examine the transverse momentum distributions in
dijet production at large rapidity intervals at the Tevatron, using the BFKL
resummation.


title: The Higgs sector of a supersymmetric left-right model

abstract:
  We study the symmetry breaking sector of a supersymmetric left-right model
based on the gauge group $SU(2)_L\times SU(2)_R\times U(1)_{B-L}$. The explicit
mass matrices of neutral, singly charged and doubly charged scalars are
constructed. In the minimum the $R$-parity is found to be spontaneously broken.
An experimentally interesting feature of the model is that one of the doubly
charged scalars is possibly light enough to be seen in the next linear
collider.


title: Light Gluinos and $\Gamma(Z\rightarrow b\overline{b})$

abstract:
  We discuss the anomaly in the $b$ branching ratio of the $Z$ in the context
of the light gluino scenario.


title: Massive States in Chiral Perturbation Theory

abstract:
  It is shown that the chiral nonanalytic terms generated by $\Delta_{33}$
resonance in the nucleon self-energy is reproduced in chiral perturbation
theory by perturbing appropriate local operators contained in the pion-nucleon
effective Lagrangian itself.


title:
Flavor and Spin Contents of the Nucleon in the Quark Model with Chiral
  Symmetry

abstract:
  A simple calculation in the framework of the chiral quark theory of Manohar
and Georgi yields results that can account for many of the ''failures'' of the
naive quark model: significant strange quark content in the nucleon as
indicated by the value of $\sigma _{\pi N},$ the $\overline{u}$-$\overline{d} $
asymmetry in the nucleon as measured by the deviation from Gottfried sum rule
and by the Drell-Yan process, as well as the various quark contributions to the
nucleon spin as measured by the deep inelastic polarized lepton-nucleon
scatterings.


title:
Calculation of Particle Production by Nambu Goldstone Bosons with
  Application to Inflation Reheating and Baryogenesis

abstract:
  A semiclassical calculation of particle production by a scalar field in a
potential is performed. We focus on the particular case of production of
fermions by a Nambu-Goldstone boson $\theta$. We have derived a (non)local
equation of motion for the $\theta$-field with the backreaction of the produced
particles taken into account. The equation is solved in some special cases,
namely for purely Nambu-Goldstone bosons and for the tilted potential $
U(\theta ) \propto m^2 \theta^2 $. Enhanced production of bosons due to
parametric resonance is investigated; we argue that the resonance probably
disappears when the expansion of the universe is included. Application of our
work on particle production to reheating and an idea for baryogenesis in
inflation are mentioned.


title:
Analysis of Transverse Muon Polarization in $K^+\to \pi^0\mu^+\nu$ and
  $K^+\to \mu^+\nu\gamma$ Decays with Tensor Interactions

abstract:
  The T violating transverse muon polarizations in $K^+\to \pi^0\mu^+\nu$ and
$K^+\to \mu^+\nu\gamma$ decays due to tensor interactions are studied. The
magnitudes of these polarizations over the allowed phase space are presented.


title:
Single Heavy Lepton Production in High Energy Electron-Positron
  Collisions

abstract:
  The production and decay of exotic leptons are discussed in the context of
the vector singlet, vector doublet and fer\-mion mirror-fer\-mion models, at
c.m. energies $\sqrt{s}=190GeV$ (LEP II) and $\sqrt{s}=500GeV$ (NLC). The model
dependence of total cross sections and kinematic distributions at these
energies is shown to be weak for these three extended models, indicating that
it would be difficult to establish which of them is best fit to describe the
underlying new physics, should exotic leptons be detected. We suggest that, in
order to resolve this difficulty, one should measure the angular distributions
of single exotic leptons in longitudinally polarized $e^+e^-$ collisions.


title: Conservation Laws and Sum Rules in the Heavy Quark Limit

abstract:
  In the heavy quark limit, hadrons appear as eigenstates of the light degrees
of freedom under the static color field of the heavy quark. In this formalism,
the weak form factors appear naturally as the overlaps of the initial and final
wavefunctions of the light degrees of freedom, and the Bjorken and Voloshin sum
rules are statements of conservation of probability and energy. Moreover,
parity conservation can lead to a sum rule which relates weak form factors at
different kinematic points. {}From this sum rule, model independent lower
bounds on Isgur--Wise form factors can be obtained analytically.


title:
From $m_{d}=m_{e}$ to Realistic Mass Relations in Quark-Lepton Symmetric
  Models

abstract:
  In recent years a new potential symmetry of fundamental particle physics has
been investigated --- discrete quark-lepton symmetry. When this symmetry is
implemented, however, it often leads to either of the unrealistic predictions
$m_{u}=m_{e}$ or $m_{d}=m_{e}$. This paper considers two possible ways models
based on $m_{d}=m_{e}$ can be made realistic.


title: Leading-Log Effects in the Resonance Electroweak Form Factors

abstract:
  We study log corrections to inelastic scattering at high Bjorken x for Q^2
from 1 to 21 GeV^2. At issue is the presence of log corrections, which can be
absent if high x scattering has damped gluon radiation. We find logarithmic
correction of the scaling curve extrapolated to low Q^2 improves the duality
between it and the resonance plus background data in the Delta region,
indicating log corrections exist in the data. However, at W > 2 GeV and high x,
the data shows a (1-x)^3 form. Log corrections in one situation but not in
another can be reconciled by a W- or Q^2- dependent higher twist correction.


title: Resonant Neutrino Interactions and Mixing

abstract:
  We investigate the resonant interaction of neutrinos in matter in the
presence of mixing. At energies near the W resonance, oscillations are absent;
the survival probability of electron antineutrinos is suppressed due to the
presence of open inelastic channels.


title: Solar Neutrinos and the Principle of Equivalence

abstract:
  We study the proposed solution of the solar neutrino problem which requires a
flavor nondiagonal coupling of neutrinos to gravity. We adopt a
phenomenological point of view and investigate the consequences of the
hypothesis that the neutrino weak interaction eigenstates are linear
combinations of the gravitational eigenstates which have slightly different
couplings to gravity, $f_1G$ and $f_2G$, $|f_1-f_2| << 1$, corresponding to a
difference in red-shift between electron and muon neutrinos, $\Delta z/(1+z)
\sim |f_1 - f_2|$. We perform a $\chi^2$ analysis of the latest available solar
neutrino data and obtain the allowed regions in the space of the relevant
parameters. The existing data rule out most of the parameter space which can be
probed in solar neutrino experiments, allowing only $|f_1 - f_2| \sim 3 \times
10^{-14}$ for small values of the mixing angle ($2 \times 10^{-3} \le
\sin^2(2\theta_G) \le 10^{-2}$) and $10^{-16} \stackrel{<}{\sim} |f_1 - f_2|
\stackrel{<}{\sim}10^{-15}$ for large mixing ($0.6 \le \sin^2(2\theta_G) \le
0.9$). Measurements of the $^8{\rm B}$-neutrino energy spectrum in the SNO and
Super-Kamiokande experiments will provide stronger constraints independent of
all considerations related to solar models. We show that these measurements
will be able to exclude part of the allowed region as well as to distinguish
between conventional oscillations and oscillations due to the violation of the
equivalence principle.


title:
Signature of the Intermediate Mass Higgs Boson at the LHC With Flavor
  Tagging

abstract:
  We revisit the exclusive signature $e^\pm (\mu^\pm) + b\bar b$ in the
associated production of the intermediate mass Higgs boson with a $W$ boson. We
show that it is feasible to use this signature to identify the Higgs boson in
the lower intermediate mass region ($90$ to $130$ GeV) at the LHC with
reasonable acceptance cuts by assuming effective bottom-jet identification. We
further demonstrate that the background can be reduced with judicious cuts down
to the level of the signal.


title: A Lattice Study of the Gluon Propagator in the Landau Gauge

abstract:
  We present the results of two high-statistics studies of the gluon propagator
in the Landau gauge, at $\beta=6.0$, on different lattice volumes. The
dependence of the propagator on the momenta is well described by the expression
$G(k^2) = \Big[ M^2+Z\cdot k^2(k^2/ \Lambda^2)^\eta)\Big]^{-1}$. We obtain a
precise determination of $\eta=0.532(12)$, and verify that $M^2$ does not
vanish in the infinite volume limit.


title:
Two-Loop ${\cal O}(\alpha_s^2)$ Correction to the $H\to b\bar b$ Decay
  Rate Induced by the Top Quark

abstract:
  We present the two-loop QED and QCD corrections to the $f\bar fH$ Yukawa
coupling that are induced by the exchange of a virtual photon or gluon,
respectively, with a heavy-fermion loop inserted. As an application, we study
the corresponding $\O(\alpha_s^2M_H^2/m_t^2)$ correction to the $H\to b\bar b$
decay rate.


title:
CP-Violatiing Asymmetries in $e^+e^-\ra t\bar{t}$ with Longitudinally
  Polarized Elecrtons

abstract:
  New CP-violating asymmetries of decay leptons in $e^+\,e^-\;\ra\;t\,\bar{t}$,
arising from electric and weak dipole couplings of $t\,\bar{t}$ to $\gamma$ and
$Z$, are examined in the case of unpolarized and longitudinally polarized
electrons. The new asymmetries measured together with the old ones can help to
determine independently the real and imaginary parts of the electric as well as
weak dipole couplings. Longitudinal beam polarization, if present, obviates the
need for the simultaneous measurement of more than one asymmetry, and enhances
considerably the sensitivity to the CP-violating parameters. Numerical results
are presented for the Next Linear Collider with $\sqrt{s}=500$ GeV and
$\int{\cal L}\,dt\;=\;10\,{\rm fb}^{-1}$.


title: The Bloom-Gilman Duality and Leading Logarithms

abstract:
  The existing inclusive electroproduction data base allow us a look at the
issue of the relative behaviors of background and resonance excitations, a part
of the Bloom-Gilman duality. These data lack accuracy at high Q^2, but
establish PQCD scaling in the resonance region and even allow us a glimpse at
the leading logarithmic corrections due to the gluon radiation and its possible
quenching at large W and x. These should inspire better quality experimental
tests at facilities like CEBAF II.


title:
Sensitivity to properties of the phi-meson in the nucleon structure in
  the chiral soliton model

abstract:
  The influence of the phi-meson on the nucleon properties in the chiral
soliton model is discussed.


title:
The Three-Loop Free Energy for High-Temperature QED and QCD with
  Fermions

abstract:
  We compute the free energy density for gauge theories, with fermions, at high
temperature and zero chemical potential. Specifically, we analytically compute
the free energy through $O(g^4)$, which requires the evaluation of three-loop
diagrams. This computation extends our previous result for pure gauge QCD.


title: THE PROCESS $e^+ e^- \rightarrow l \bar l q \bar q$ AT LEP AND NLC

abstract:
  The cross sections for the reaction $e^+ e^- \rightarrow l \bar l q \bar q $
and for similar four fermion production processes at LEP~1, LEP~2 and the NLC
are calculated. Due to the extraordinary symmetry properties of the process,
very compact analytical formulae describe the double differential distributions
in the invariant masses of the $l \bar l$ and $q \bar{q}$ pairs. The total
cross sections may be obtained with two numerical integrations.


title: Heavy Quark Masses from QCD Sum Rules

abstract:
  I review recent determinations of the (on-shell) charm- and beauty-quark
masses in the framework of relativistic and non-relativistic ratios of Laplace
transform QCD moment sum rules. The validity of the non-relativistic version of
QCD sum rules in this particular application is discussed.


title: Deconfinement and Chiral-Symmetry Restoration in Finite Temperature QCD

abstract:
  QCD sum rules are based on the Operator Product Expansion of current
correlators, and on QCD-hadron duality. An extension of this program to finite
temperature is discussed. This allows for a study of deconfinement and
chiral-symmetry restoration. In addition, it is possible to relate certain
hadronic matrix elements to expectation values of quark and gluon field
operators by using thermal Finite Energy Sum Rules. In this way one can
determine the temperature behaviour of hadron masses and couplings, as well as
form factors. An attempt is made to clarify some misconceptions in the existing
literature on QCD sum rules at finite temperature.


title: Bounds on Anomalous Gauge Boson Couplings From Partial Z Widths at LEP

abstract:
  We place bounds on anomalous gauge boson couplings from LEP data with
particular emphasis on those couplings which do not contribute to $Z$ decays at
tree level. We use an effective field theory formalism to compute the one-loop
corrections to the $Z\rightarrow {\overline f} f$ decay widths resulting from
non-standard model three and four gauge boson vertices. We find that the
precise measurements at LEP constrain the three gauge boson couplings at a
level comparable to that obtainable at LEPII and LHC.


title:
Fermion Production in the Background of Minkowski Space Classical
  Solutions in Spontaneously Broken Gauge Theory

abstract:
  We investigate fermion production in the background of Minkowski space
solutions to the equations of motion of $SU(2)$ gauge theory spontaneously
broken via the Higgs mechanism. First, we attempt to evaluate the topological
charge $Q$ of the solutions. We find that for solutions $Q$ is not well-defined
as an integral over all space-time. Solutions can profitably be characterized
by the (integer-valued) change in Higgs winding number $\Delta N_H$. We show
that solutions which dissipate at early and late times and which have nonzero
$\Delta N_H$ must have at least the sphaleron energy. We show that if we couple
a quantized massive chiral fermion to a classical background given by a
solution, the number of fermions produced is $\Delta N_H$, and is not related
to $Q$.


title:
Spin dependent structure function $ g_{2}(x)$ in quark-parton model.
  Possible interpretation and numerical estimates

abstract:
  It is shown that in the special infinite momentum frame where photon has pure
transverse components at $P\rightarrow\infty$ the spin-dependent deep inelastic
structure function $ g_{2}(x)$ has a reasonable interpretation in terms of
quark-parton wave functions, whereas in the conventional frame where photon has
pure z-component the parton model fails for $ g_{2}(x)$.The spin dependent
structure functions $ g_{1}(x)$ and $ g_{2}(x)$ have been calculated in the
relativistic quark model constructed in such frame. The results indicate
significant twist-3 contribution.


title: Outreach and Education on High Energy Physics

abstract:
  We review ongoing efforts and discuss possible future directions in informing
the public and educating students about Particle Physics.


title: $K_{e5}$ Decays in Chiral Perturbation Theory

abstract:
  We evaluate the branching ratios for the decays $K\rightarrow \pi\pi\pi e\nu$
at leading order in chiral perturbation theory and give an isospin relation for
the decay rates.


title: Unitarity And Anomalous Top-Quark Yukawa Couplings

abstract:
  Unitarity constraints on anomalous top-Higgs couplings are examined. We also
compare the unitarity constraints with the constraints from electroweak
baryogenesis and electric dipole moments derived earlier.


title: Stability of Fine Tuned Hierarchies in Strongly Coupled Chiral Models

abstract:
  A fine tuned hierarchy between a strongly coupled high energy compositeness
scale and a much lower chiral symmetry breaking scale is a requisite ingredient
in many models of dynamical electroweak symmetry breaking. Using a
nonperturbative continuous Wilson renormalization group equation approach, we
explore the stability of such a hierarchy against quantum fluctuations.


title: Spectral Analysis of Neutrino Mixing Mechanisms

abstract:
  The prospects of using spectral measurements of solar neutrinos to
distinguish different mechanisms of neutrino flavor mixing are analyzed. The
mechanisms studied include the conventional mass mixing mechanism and an
alternative mechanism which assumes a flavor nondiagonal neutrino-gravity
coupling.


title: Glueballs and Instantons

abstract:
  We study correlation functions and Bethe Salpeter amplitudes for the scalar,
the pseudoscalar and the tensor glueballs using an instanton-based model of the
QCD vacuum. We consider both the pure gauge case and the situation for real QCD
with two light quark flavors. We show that instantons lead to a strong
modification of the correlation functions as compared to their perturbative
behavior. In particular, we find a strong attractive force in the
$J^{CP}=0^{++}$ channel and repulsion in the $0^{+-}$ channel. Due to the
strong classical field of the instantons, these effects are much larger than
the spin splittings observed in mesons made of quarks. The resulting masses,
coupling constants and wave functions appear to be in agreement with lattice
gauge simulations.


title: Amplitude Zeros in Radiative Decays of Scalar Particles

abstract:
  We study amplitude zeros in radiative decay processes with a photon or a
gluon emission of all possible scalar particles(e.g. scalar leptoquarks) which
may interact with the usual fermions in models beyond the standard model. For
the decays with a photon emission, the amplitudes clearly exhibit the
factorization property and the differential decay rates vanish at specific
values of a certain variable which are determined only by the electric charges
of the particles involved and independent of the particle masses and the
various couplings. For the decays with a gluon emission, even though the zeros
are washed away, the differential decay rates still have distinct minima. The
branching ratios as a function of leptoquark masses are presented for the
scalar leptoquark decays. We also comment on the decays of vector particles
into two fermions and a photon.


title: Evolution of Fields in a Second Order Phase Transition

abstract:
  We analyse the evolution of scalar and gauge fields during a second order
phase transition using a Langevin equation approach. We show that topological
defects formed during the phase transition are stable to thermal fluctuations.
Our method allows the field evolution to be followed throughout the phase
transition, for both expanding and non-expanding Universes. The results verify
the Kibble mechanism for defect formation during phase transitions.


title: Fermi-Dirac Distributions for Quark Partons

abstract:
  We propose to use Fermi-Dirac distributions for quark and antiquark partons.
It allows a fair description of the $x$-dependence of the very recent NMC data
on the proton and neutron structure functions $F_2^p(x)$ and $F_2^n(x)$ at
$Q^2=4$ GeV$^2$, as well as the CCFR antiquark distribution $x\overline q(x)$.
We show that one can also use a corresponding Bose-Einstein expression to
describe consistently the gluon distribution. The Pauli exclusion principle,
which has been identified to explain the flavor asymmetry of the light-quark
sea of the proton, is advocated to guide us for making a simple construction of
the polarized parton distributions. We predict the spin dependent structure
functions $g_1^p(x)$ and $g_1^n(x)$ in good agreement with EMC and SLAC data.
The quark distributions involve some parameters whose values support well the
hypothesis that the violation of the quark parton model sum rules is a
consequence of the Pauli principle.


title:
Unified QCD Evolution Equations and the Dominant Behaviour of Structure
  Functions at Low X

abstract:
  We consider a system of evolution equations for quark and gluon structure
functions satisfying the leading-logarithmic behaviour due to both QCD
collinear $ \left(LLQ^2 \right) $ and infrared $ (LL1/x) $ singularities. We
show that these equations leave undetermined an arbitrary regular function of
$j$ in the Mellin-transformed weights. We consider the constraints resulting
from energy-momentum conservation and from the decoupling of quark loops in the
leading $ j $-plane singularity. These constraints can be fulfilled without
influencing the leading-log terms. As a particular consequence of the second
constraint, the location of the leading singularity is determined in terms of
the $ (LL1/x) $ and $ \left(LLQ^2 \right) $ kernels. It leads to a value
significantly lower than the $ LL1/x $ evaluation, while remaining at $j > 1,$
and compatible with the behaviour of structure functions observed at HERA.


title: Low Energy Effective Lagrangian of the Bess Model

abstract:
  In this paper the low energy limit of the BESS model is studied in a
systematic way. The method consists in eliminating the heavy vector field, by
use of its classical equations of motion, in the infinite mass limit. After the
elimination of the heavy degrees of freedom we get additional terms to the
Standard Model lagrangian. After a finite renormalization of the ordinary gauge
bosons wave functions, and redefinition of the lagrangian couplings in terms of
$M_Z$, the fine structure constant and the Fermi constant, we can read directly
the deviations from the Standard Model. By this procedure we can extend a
result previously derived to the case in which the heavy vector bosons have a
direct coupling to fermions. Consequences for the anomalous trilinear couplings
are discussed.


title: Causal quantum mechanics treating position and momentum symmetrically

abstract:
  De Broglie and Bohm formulated a causal quantum mechanics with a phase space
density whose integral over momentum reproduces the position probability
density of usual statistical quantum theory. We propose a causal quantum theory
with a joint probability distribution such that the separate probability
distributions for position and momentum agree with usual quantum theory. Unlike
the Wigner distribution the suggested distribution is positive definite and
obeys the Liouville condition.


title: Beyond the Standard Model in the Lepton Sector

abstract: Invited review talk at Glasgow ICHEP Conference, session Pa4


title: Schemes for Neutrino Mass and Mixing

abstract: Review at session Pa7, Glasgow ICHEP conference


title:
Active Sterile Neutrino Conversions in a Supernova with Random Magnetic
  Fields

abstract:
  {Large enough random magnetic fields may affect in an important way neutrino
conversion rates, even in the case where neutrinos have zero transition
magnetic moments. We consider their effect in the case of active to sterile
\neu conversions in a supernova and show that for KeV neutrino masses these
limits may overcome those derived for the case of zero magnetic field.}


title: Single Spin Asymmetry in Inclusive Pion Production

abstract:
  It is shown how the single spin asymmetry observed in inclusive pion
production is related, in the helicity basis, to the imaginary part of the
product of two different distribution amplitudes, rather than to the usual
quark and gluon distribution functions; there is then no reason why it should
be zero even in massless perturbative QCD, provided the quark intrinsic motion
is taken into account. A simple model is constructed which reproduces the main
features of the data.


title: Target independence of the `proton spin' effect

abstract:
  Recent work by the author in collaboration with S. Narison and G. Veneziano
on the EMC-SMC-SLAC `proton spin' effect is reviewed. This uses a novel
approach to deep inelastic scattering in which the matrix elements arising from
the OPE are factorised into composite operator propagators and proper vertices.
For polarised $\mu p$ scattering, the composite operator propagator is equated
to the square root of the first moment of the QCD topological susceptibility,
$\sqrt{\chi^\prime(0)}$. We evaluate $\chi^\prime(0)$ using QCD spectral sum
rules and find a significant suppression relative to its OZI expectation. This
is identified as the source of the violation of the Ellis-Jaffe sum rule for
the first moment of the polarised proton structure function $g_1^p$. Our
predictions, $\int_0^1 dx g_1^p(x;Q^2=10GeV^2) = 0.143\pm 0.005$ and
$\Delta\Sigma =0.353\pm 0.052$, are in excellent agreement with the new SMC
data. This supports our earlier conjecture that the suppression in the flavour
singlet component of the first moment of $g_1^p$ is a target-independent
feature of QCD related to the $U(1)$ anomaly and is not a special property of
the proton structure.


title: Particle Physics with High Energy Neutrinos

abstract:
  The topic of this review is the particle astrophysics of high energy
neutrinos. High energy is defined as $E_{\nu} > 100$~MeV. Main topics include:
-- atmospheric neutrinos and muons from $\pi$, $K$ and charm decay. They probe
uncharted territory in neutrino oscillations and constitute both the background
and calibration of high energy neutrino telescopes, -- sources of high energy
neutrino beams: the galactic plane, the sun, X-ray binaries, supernova remnants
and interactions of extra-galactic cosmic rays with background photons, -- an
extensive review of the mechanisms by which active galaxies may produce high
energy particle beams, -- high energy neutrino signatures of cold dark matter
and, -- a brief review of detection techniques (water and ice Cherenkov
detectors, surface detectors, radio- and acoustic detectors, horizontal
airshower arrays) and the instruments under construction.


title:
On the connection between the pinch technique and the background field
  method

abstract:
  The connection between the pinch technique and the background field method is
further explored. We show by explicit calculations that the application of the
pinch technique in the framework of the background field method gives rise to
exactly the same results as in the linear renormalizable gauges. The general
method for extending the pinch technique to the case of Green's functions with
off-shell fermions as incoming particles is presented. As an example, the
one-loop gauge independent quark self-energy is constructed. We briefly discuss
the possibility that the gluonic Green's functions, obtained by either method,
correspond to physical quantities.


title: The Case for a Kilometer-Scale High Energy Neutrino Detector

abstract:
  Doing astronomy with photons of energies in excess of a GeV has turned out to
be extremely challenging. Efforts are underway to develop instruments that may
push astronomy to wavelengths smaller than $10^{-14}$~cm by mapping the sky in
high energy neutrinos instead. Neutrino astronomy, born with the identification
of thermonuclear fusion in the sun and the particle processes controlling the
fate of a nearby supernova, will reach outside the galaxy and make measurements
relevant to cosmology. The field is immersed in technology in the domains of
particle physics to which many of its research goals are intellectually
connected. To mind come the search for neutrino mass, cold dark matter
(supersymmetric particles?) and the monopoles of the Standard Model. While a
variety of collaborations are pioneering complementary methods by building
telescopes with effective area in excess of 0.01~km$^2$, we show here that the
natural scale of a high energy neutrino telescope is 1~km$^2$. With several
thousand optical modules and a price tag unlikely to exceed 100 million
dollars, the scope of a kilometer-scale instrument is similar to that of
experiments presently being commissioned such as the SNO neutrino observatory
in Canada and the Superkamiokande experiment in Japan.


title:
Charm Mass Dependence of the $\CO(\alpha_s^2 n_f)$ Correction to
  Inclusive $B\rightarrow X_c e\bar\nu_e$ Decay

abstract:
  We compute the $\alpha_s^2 n_f$ perturbative QCD contribution to semileptonic
B decay, including the finite mass of the charm quark. This result provides an
estimate of the size of the two-loop correction, which is found to be about
50\% of the one-loop correction. We use these results to set the scale for the
one-loop correction using the scheme of Brodsky, Lepage and Mackenzie and find
a BLM scale of $\mu_{\rm BLM} = 0.13\, m_b$, when the inclusive semileptonic
rate is expressed in terms of the $b$ and $c$ quark pole masses and the \msbar
strong coupling. The two loop correction lies roughly midway between that
obtained at $m_c=0$ and that obtained in the Shifman-Voloshin limit $m_b,
m_c\gg m_b-m_c\gg\Lambda_{\rm QCD}$ while the corresponding BLM scale is
somewhat closer to that obtained in the former case.


title: Unique Signature of Electroweak Penguin In Pure Hadronic $B$ Decays

abstract:
  We study elelctroweak penguin contributions in pure hadronic $B$ decays in
the Standard and two-Higgs-doublet models. We find that in $B_s\rightarrow
\pi^0 (\eta\;, \phi)$ and $B_s\rightarrow \rho^0 (\eta\;, \phi)$ decays, the
electroweak penguin contributions dominate over all other contribuitons. These
processes provide unique signatures of electroweak penguin in pure hadronic
processes. These modes could be in measureable range of future $B$ facilities.


title:
A Natural Explanation of All Solar Neutrino Data by Resonant Spin-Flavor
  Precession Scenario

abstract:
  It is emphasized that the $E_{\nu}$ (neutrino energy) spectrum of the $\nu_e$
survival probability in the Resonant Spin-Flavor Precession (RSFP) scenario has
very desirable shape to reconcile all existing solar neutrino data. As the
result, the RSFP scenario is shown to have rather broad allowed region to
reconcile the data in the ($B,\ \Delta m^2$) plane, with $B$ being the magnetic
field strength inside the Sun. The sensitivity of the allowed region on the
different choices of the $B$ profile, and the time variations of the solar
neutrino event rates in the RSFP scenario are also discussed in some detail.


title:
Parton Model From Field Theory via Light-Front Current Algebra: The
  Good, the Bad, and the Terrible

abstract:
  The emergence of parton model from field theory in the context of light-front
current algebra and naive canonical manipulations is reviewed. Shortcomings of
the naive canonical picture, especially concerning renormalization issues are
discussed. To illustrate the novel aspects of the renormalization problem in
light-front dynamics, the scaling behavior of different components of currents
under the dual power counting is stressed. It is noted that the application of
dual power counting to deep inelastic phenomena may provide a simple intuitive
understanding of twist. Talk Presented at the Fourth International Workshop on
Light Cone Quantization and Non-Perturbative Dynamics, Polana Zgorzelisko,
Poland.


title: Standard Model of the Electroweak Interaction: Theoretical Developments

abstract:
  We review recent theoretical progress in the computation of radiative
corrections beyond one loop within the standard model of electroweak
interactions, both in the gauge and Higgs sectors. In the gauge sector, we
discuss universal corrections of $\O(G_F^2M_H^2M_W^2)$, $\O(G_F^2m_t^4)$,
$\O(\alpha_sG_FM_W^2)$, and those due to virtual $t\bar t$ threshold effects,
as well as specific corrections to $\Gamma\left(Z\to b\bar b\right)$ of
$\O(G_F^2m_t^4)$, $\O(\alpha_sG_Fm_t^2)$, and $\O(\alpha_s^3)$ including
finite-$m_b$ effects. We also present an update of the hadronic contributions
to $\Delta\alpha$. Theoretical uncertainties, other than those due to the lack
of knowledge of $M_H$ and $m_t$, are estimated. In the Higgs sector, we
concentrate on $\Gamma\left(H\to f\bar f\,\right)$ and consider in
$\O(\alpha_sG_Fm_t^2)$ the universal corrections and those which are specific
for the $\scriptstyle b\bar b$ mode, as well as $\O(\alpha_s^2)$ corrections in
the $q\bar q$ channels including the finite-$m_q$ terms.


title:
Soft Photons in Hadron-Hadron Collisions: Synchrotron Radiation from the
  QCD Vacuum?

abstract:
  We discuss the production of soft photons in high energy hadron-hadron
collisions. We present a model where quarks and antiquarks in the hadrons emit
``synchrotron light'' when being deflected by the chromomagnetic fields of the
QCD vacuum, which we assume to have a nonperturbative structure. This gives a
source of prompt soft photons with frequencies $\omega <= 300 MeV$ in the c.m.
system of the collision in addition to hadronic bremsstrahlung. In comparing
the frequency spectrum and rate of ``synchrotron'' photons to experimental
results we find some supporting evidence for their existence. We make an
exclusive--inclusive connection argument to deduce from the ``synchrotron''
effect a behaviour of the neutron electric formfactor $G_E^n(Q^2)$ proportional
to $(Q^2)^{1/6}$ for $Q^2 < 20 fm^{-2}$. We find this to be consistent with
available data. In our view, soft photon production in high energy
hadron-hadron and lepton-hadron collisions as well as the behaviour of
electromagnetic hadron formfactors for low $Q^2$ are thus sensitive probes of
the nonperturbative structure of the QCD vacuum.


title: Proper-time methods in the presence of non-constant background fields

abstract:
  A formalism is developed to enable the construction of the effective action
and related quantities in QED for the case of time-varying background electric
fields. Some examples are studied and evidence is sought for a possible
transition to a phase in which chiral symmetry is spontaneously broken.
YCTP-P14-94


title: Surprises from Quarkonium Decay into Photons

abstract:
  The perturbative QCD approach to quarkonium decay into a photon and hadrons
is reconsidered. It is shown that a consistent treatment within perturbative
QCD calls for the introduction of a fragmentation contribution which has been
neglected so far. The ensuing phenomenological implications are discussed, and,
in particular, the possibility of measuring the gluon fragmentation function of
the photon is addressed.
  *To appear in the proceedings of the workshop QCD94, Montpellier, July '94.


title: Next-to-Leading Corrections at Small X

abstract:
  We discuss the role of sub-leading corrections to deep inelastic processes in
the small-x regime, and report recent results on the calculation of coefficient
functions and quark anomalous dimensions.
  *To appear in the proceedings of the workshop QCD94, Montpellier, July '94.


title: Structure Formation with Majoron Supermultiplet

abstract:
  We show that the late-decaying particle scenario may be realized in the
supersymmetric singlet majoron model with the majoron scale $10-200$ TeV. The
smajoron decaying into two neutrinos is the late-decaying particle with the
mass $0.1-1$ TeV and the life-time $2\times10^3-8\times10^4$ seconds. The lower
limit of the majorino mass is $4-40$ TeV in order to avoid the overclosure of
the universe due to the decay-produced LSP. The muon neutrino and the tau
neutrino can be used to explain the atmospheric and the solar neutrino deficit.


title:
Detecting the Intermediate-Mass Neutral Higgs Boson at the LHC Through
  $pp \to W H$

abstract:
  We examine the exclusive signature $pp \to WH \to \ell \nu\;b \bar b$ at the
LHC. Although the backgrounds, principally arising from top production and
$Wjj$, are quite severe, it is shown that judicious application of phase-space
cuts and the use of $b$-tagging can in fact greatly enhance the detectability
of this channel. (Presented at the Eighth Meeting of the Division of Particles
and Fields Albuquerque, New Mexico, August 2-6, 1994.)