title: The QCD Scale in the Heavy Quark Expansion

abstract:
  We argue that consistency of the combined heavy quark and chiral effective
lagrangian requires the QCD scale which multiplies $1/M$ in the heavy quark
expansion to be the chiral symmetry breaking scale, $\Lambda_{CSB}$, rather
than the QCD scale, $\Lambda_{QCD}$. This means that either there is large
uncertainty in the accuracy with which the heavy quark effective theory can be
applied to $c$ quarks or the cutoff scale of the heavy quark chiral effective
theory is lower than has been assumed.


title: See-Saw Type Mixing and $ \nu_{\mu} \to \nu_{\tau} $ Oscillations

abstract:
  We consider $ \nu_{\mu} \to \nu_{\tau} $ oscillations under the assumption
that there is a see-saw type mixing of the light neutrinos with heavy Majorana
particles. It is shown that the existing data, including the recent LEP data,
do not exclude the possibility that the additional terms in the transition
probability due to this mixing could be of the same order of magnitude as the
usual oscillating term. Detail investigations of $ \nu_{\mu} \to \nu_{\tau} $
transitions in future CERN and Fermilab experiments could allow to get
informations not only about the neutrino masses and mixing but also about the
mixing of neutrinos with heavy Majorana particles.


title:
Leading Higgs Mass Dependent Corrections to the Standard Model
  Lagrangian and its Two Higgs Doublet Extension

abstract:
  We present an alternative calculation for the leading Higgs mass dependent
one--loop corrections to the standard model Lagrangian, using a background
field technique. Cross--sections computed from our one--loop Lagrangian provide
a check of and reproduce results already obtained in the existing literature
using diagrammatic methods, as well as allowing an analysis of other processes
involving longitudinally polarized $W^\pm$s and $Z^0$s. We concentrate on the
processes $WW\rightarrow f\bar{f}$ and $f\bar{f}\rightarrow WW$. We extend our
result to the case of a two Higgs doublet model, when one of the physical Higgs
is much heavier than the other particles and analyze the tree+one--loop
unitarity bounds on the scale at which signs of a strongly interacting sector
(or the heaviest Higgs) must turn up.


title: Resolved Virtual Photon Contributions to inelastic $e-p$ Scattering

abstract:
  The problem of dealing with the resolved photon contribution to
$P^2$-integrated $ep$ cross sections is discussed. Suitable approximations have
to be found, since no parametrization of the photon structure function in the
full range of virtuality of the exchanged photon exists.


title:
A Probe of New Physics in Top Quark Pair Production at $e^-e^+$
  Colliders

abstract:
  We describe how to probe new physics through examination of the form factors
describing the Ztt couplings via the scattering process e^-e^+->t+tbar. We
focus on experimental methods on how the top quark momentum can be determined
and show how this can be applied to select polarized samples of $t\bar{t}$
pairs through the angular correlations in the final state leptons. We also
study the dependence on the energy and luminosity of an \ee\ collider to probe
a CP violating asymmetry at the $10^{-2}$ level.}


title: $b \to s \gamma$ and Minimal Supersymmetry

abstract:
  The contribution to the decay $b\to s \gamma$ in the Minimal Supersymmetric
Standard Model with radiative electroweak breaking is presented. The impact of
a detection of this inclusive decay at the SM level is discussed. Results for
other inclusive $b-s$ transitions are also mentioned.


title: Nucleon and delta masses in QCD

abstract:
  Using the positivity of the path integral measure of $QCD$ and defining a
structure for the quark propagator in a background field according to the
fluxon scenario for confinement, we calculate and compare the correlators for
nucleon and delta. From their shape we elucidate about the origin of their mass
difference, which in our simplified scenario is due to the tensor structure in
the propagator. This term arises due to a dynamical mechanism which is
responsible simultaneously for confinement and spontaneous chiral symmetry
breaking. Finally we discuss, by comparing the calculated correlators with the
Lehmann representation, the possibility that a strong CP and/or P violation
occurs as a consequence of a specific mechanism for confinement.


title:
Proposals for Studying TeV $W_L W_L \rightarrow W_L W_L$ Interactions
  Experimentally

abstract:
  We discuss how to experimentally study the symmetry breaking sector by
observing $W_L W_L \rightarrow W_L W_L$ interactions in the TeV region. We
discuss some general features of the event structure in the signal and
background events. Various tricks to enhance the signal--to--background ratio
are also presented. We show how to detect longitudinal $W$--bosons either in
the central rapidity region of the detector or in the beam pipe direction.


title: CP violation in $J/\psi \rightarrow \Lambda \bar \Lambda$

abstract:
  We study CP violation in $J/\psi \rightarrow \Lambda \bar{\Lambda}$ decay.
This decay provides a good place to look for CP violation. Some observables are
very sensitive to the $\Lambda$ electric dipole moment $d_\Lambda$ and
therefore can be used to improve the experimental upper bound on $d_\Lambda$.
CP violations in the lepton pair decays of $J/\psi$ and $\Upsilon$ are also
discussed.


title: Will discrete symmetries help solve the hierarchy problem ?

abstract:
  We find that massless Higgs doublets at the GUT scale can be the natural
result of a discrete symmetry. Such a mechanism does not require elaborate fine
tuning or complicated particle content. The same discrete symmetry will also
protect against proton decay and flavor changing neutral currents. However,
this mechanism always predicts non-minimal standard models. An explicit example
of how this mechanism works is also included.


title: Strangeness in the Skyrme and in Nambu-Jona Lasinio Models

abstract:
  We discuss the phenomenology of SU(3) Skyrme and Nambu--Jona-Lasinio models.
We show that while the Skyrme model, in its simplest version, is unable do
reproduce the hyperon spectrum, the NJL model describes both hyperon and
isospin splittings with satisfactory accuracy. The difference between the two
models lies in new {\em anomalous} moments of inertia, which vanish in the
Skyrme model and get non-zero contribution from the {\em valence} quarks in the
NJL model


title: Trinification and the Strong P Problem

abstract:
  Models with spontaneously broken parity symmetry can solve the strong $CP$
problem in a natural way. We construct such a model in the context of $\SU3^3$
unification. Parity has the conventional meaning in this model, and the gauge
group is unified.


title: Recent Work on Standard Solar Models

abstract:
  Recent results on standard solar models are reviewed. I shall summarize
briefly three of the themes that I stressed at the Neutrino '92 Conference: 1)
Different solar model codes give the same answers when the same input data are
used; 2) Improved calculations of standard solar models include helium
diffusion, the Livermore radiative opacity, the meteoritic iron abundance, and
a variety of other corrections; and 3) There are a few basic rules that should
be followed in using standard solar models. At the Neutrino '92 Conference, I
reviewed in more detail the recent work on standard solar models by Marc
Pinsonneault and myself. This work has by now appeared in print (Rev. Mod.
Phys. 64, 885, 1992, hereafter Paper I, and ApJ Letters, 69, 717, 1992, Paper
II). Therefore, there is no need for me to repeat the details here.


title:
Mass of the Lightest Higgs Boson in the Minimal Supersymmetric Standard
  Model with an Additional Singlet

abstract:
  An upperbound on the mass of the lightest neutral scalar Higgs boson is
calculated in an extended version of the minimal supersymmetric standard model
that contains an additional Higgs singlet. We integrate the renormalization
group equations of the model, and impose low energy boundary conditions
consistent with present experimental results, and ultra-violet conditions
following from triviality. Radiative corrections induced by a large top quark
Yukawa coupling are included in our analysis, and we find the allowed values
for the mass of the Higgs boson as a function of the mass of the top quark.
Typically, for a top quark mass $m_t=150\ GeV$, the upper bound on the Higgs
boson mass is about $25 \ GeV$ higher than in the minimal model.


title:
Disoriented Chiral Condensates: A White Paper for the Full Acceptance
  Detector at the SSC

abstract:
  Theoretical speculations and experimental data suggesting the possibility of
observing disoriented chiral condensates at a Full Acceptance Detector are
reviewed.


title: The Chiral Soliton of the Nambu-Jona-Lasinio Model

abstract:
  The baryon number one soliton of the NJL model is investigated. The Euclidian
effective action is regularized using Schwinger's proper time method. Numerical
results for the static soliton energy are presented for the cases without and
with vector and axialvector fields. It is found that the baryon number is
carried by the polarized Dirac sea of the quarks if the $a_1$ meson is included
in contrast to the case without $a_1$ where the baryon number resides on
valence quarks. Thus the model strongly supports the picture of the baryon as a
topological soliton of the meson fields. Including the $\omega $ vector meson
leads to a non--vanishing imaginary part of the Euclidian effective action even
for static solitons. Leaving the chiral circle, i.e.\ including the isoscalar
scalar meson, the soliton first seems unstable. However, we demonstrate that a
$\phi ^4$ term stabilizes the soliton. Finally, the self--consistent
two--flavor chiral soliton is embedded in the SU(3) flavor group and
collectively quantized. The predicted mass splittings for the low--lying
baryons with different hypercharge are in excellent agreement with the
experimental data if the physical value for the kaon decay constant is
substituted.


title: Bound States Can Stabilize Electroweak Strings

abstract:
  We show that the electroweak $Z-$string can be stabilized by the presence of
bound states of a complex scalar field. We argue that fermions coupled to the
scalar field of the string can also make the string stable and discuss the
physical case where the string is coupled to quarks and leptons. This
stabilization mechanism is expected to work for other embedded defects and also
for unstable solutions such as the sphaleron.


title:
Chiral Structure of the $b\rightarrow c$ Charged Current and the
  Semileptonic $\Lambda_b$ Decay

abstract:
  Using the heavy quark effective theory, chiral structure of the $b\rightarrow
c$ charged current can be determined by the semileptonic $\Lambda_b$ decay with
satisfactory theoretical accuracy. We define an asymmetry which is sensitive to
the chirality of the $b\rightarrow c$ charged current. We show that this
asymmetry has no theoretical uncertainty in the heavy quark limit. It is also
shown that $1/m_c$ correction to this asymmetry is small and disappears at the
kinematical point of zero momentum transfer.


title: Supersymmetry Tests at Fermilab: A Proposal

abstract:
  We compute the number of trilepton events to be expected at Fermilab as a
result of the reaction $p\bar p\to\chi^\pm_1\chi^0_2X$, where $\chi^\pm_1$ is
the lightest chargino and $\chi^0_2$ is the next-to-lightest neutralino. This
signal is expected to have very little background and is the best prospect for
supersymmetry detection at Fermilab if the gluino and squarks are beyond reach.
We evaluate our expressions for all points in the allowed parameter space of
two basic supergravity models: (i) the minimal $SU(5)$ supergravity model
including the severe constraints from proton decay and a not too young
Universe, and (ii) a recently proposed no-scale flipped $SU(5)$ supergravity
model. We study the plausible experimental scenaria and conclude that a large
portion of the parameter spaces of these models could be explored with
$100\ipb$ of integrated luminosity. In the minimal $SU(5)$ supergravity model
chargino masses up to $90-95\GeV$ could be probed. In the no-scale flipped
model it should be possible to probe some regions of parameter space with
$m_{\chi^\pm_1}\lsim200\GeV$, therefore possibly doubling the reach of LEPII
for chargino and neutralino (since $m_{\chi^0_2}\approx m_{\chi^\pm_1}$)
masses. In both models such probes would indirectly explore gluino masses much
beyond the reach of Fermilab.


title: Quark-Lepton Symmetry

abstract:
  Quark-lepton symmetric models are a class of gauge theories motivated by the
similarities between the quarks and leptons. In these models the gauge group of
the standard model is extended to include a ``color'' group for the leptons.
Consequently, the quarks and leptons can then be related by a $Z_2$ discrete
quark-lepton symmetry which is spontaneously broken by the vacuum. Models
utilizing quark-lepton symmetry with acceptable and interesting collider
phenomenology have been constructed. The cosmological consequences of these
models are also discussed.


title:
Flavor Changing Neutral Currents in a Realistic Composite Technicolor
  Model

abstract:
  We consider the phenomenology of a composite technicolor model proposed
recently by Georgi. Composite technicolor interactions produce four-quark
operators in the low energy theory that contribute to flavor changing neutral
current processes. While we expect operators of this type to be induced at the
compositeness scale by the flavor-symmetry breaking effects of the preon mass
matrices, the Georgi model also includes operators from higher scales that are
not GIM-suppressed. Since these operators are potentially large, we study their
impact on flavor changing neutral currents and CP violation in the neutral $B$,
$D$, and $K$ meson systems.


title: Studying the Top Quark via the W-Gluon Fusion Process

abstract:
  We show that studying the single top quark production via the $W$--gluon
fusion process can provide unique information on: (i) the measurement of the
decay width $\width$; (ii) probing the symmetry breaking mechanism by measuring
the form factor of~\tbW; (iii) testing the Effective--$W$ Approximation prior
to supercolliders; (iv) testing CP violation by observing different production
rates of $\bar p p \ra t X $ and $\bar p p \ra \bar t X$; (v) testing CP
violation from the almost hundred percent longitudinally polarized top quark
decay; in addition to the measurement of the top quark mass. In contrast to the
recent claim by R. K. Ellis and S. Parke, we show that this process is
extremely useful at the Tevatron.


title: QCD and Asymptotic Freedom: Perspectives and Prospects

abstract:
  QCD is now a mature theory, and it is possible to begin to view its place in
the conceptual universe of physics with appropriate perspective. There is a
certain irony in the achievements of QCD. For the problems which initially
drove its development only limited insight has been achieved. However I shall
argue that QCD is actually {\it more\/} special and important a theory than one
had any right to anticipate. After elaborating these quasi-philosophical
remarks, I discuss two current frontiers of physics that illustrate the
continuing vitality of the ideas. The recent wealth of beautiful precision
experiments measuring the parameters of the standard model has made it possible
to consider the unification of couplings in unprecedented quantitative detail.
One central result emerging from these developments is a tantalizing hint of
virtual supersymmetry. The possibility of phase transitions in matter at
temperatures of order $\sim 10^2 Mev$, governed by QCD dynamics, is of interest
from several points of view. There is the interesting possibility of long-range
correlations in heavy ion collisions due to the creation of large regions of
misaligned chiral condensate. Opening Talk at the Aachen conference, ``20 Years
of QCD'', June 1992.


title: What Do Solar Models Tell Us About Solar Neutrino Experiments?

abstract:
  If the published event rates of the chlorine and Kamiokande solar neutrino
experiments are correct, then the energy spectrum of neutrinos produced by the
decay of $^8$B in the sun must be different from the energy spectrum determined
from laboratory nuclear physics measurements. This change in the energy
spectrum requires physics beyond the standard electroweak model. In addition,
the GALLEX and SAGE experiments, which currently have large statistical
uncertainties, differ from the predictions of the standard solar model by $2
\sigma$ and $3 \sigma$, respectively.


title: Self-Breaking Technicolor

abstract:
  We propose a scenario in which the electroweak symmetry is spontaneously
broken by an $SU(4)$ technicolor gauge interaction which also manages to break
itself completely. The technicolor gauge bosons and technifermions are not
confined by the technicolor force, but get large masses. Starting with a single
technidoublet, one emerges with a complete standard model family of
technifermions after the symmetry breaking is complete. This suggests a broad
new avenue for model building. A few variations on the theme are mentioned.


title: Time Variations of Solar Neutrino Signals and the RSFCN Hypothesis

abstract:
  Resonant spin--flavour conversion of neutrinos (RSFCN) in twisting magnetic
fields might be at the origin of the apparent anticorrelation between the
$^{37}$Ar production--rate in the Homestake solar neutrino detector and the
solar activity. Moreover, it can account for the results of all solar neutrino
experiments reported so far including the recent results of GALLEX and SAGE.


title: Symmetry Breaking in a Generalized Skyrme Model

abstract:
  We first outline the calculations of the neutron-proton mass difference and
of the axial singlet matrix element (relevant to the "proton spin" puzzle) in a
generalized Skyrme model of pseudoscalars and vectors. These two calculations
are, perhaps surprisingly, linked to each other and furthermore are sensitive
to some fine details of symmetry breaking in the effective meson Lagrangian.
This provides a motivation for us to examine these symmetry breaking terms more
closely. We find a qualitatively new feature in the symmetry breaking pattern
of the vector meson system and discuss its significance. (Talk at Workshop on
"Baryons as Skyrme Solitons," Sept. 28-30, 1992, Siegen, Germany.)


title: Nuclear Matter Aspects of Skyrmions

abstract:
  As an alternative approach to the infinite-array description of dense matter
in the Skyrme model, we report about the properties of a single skyrmion on a
compact 3-sphere of finite radius. The density of this matter can be increased
by decreasing the hypersphere radius. As in the array calculations one
encounters a transition to a distinct high density phase characterized by a
delocalization in energy and baryon charge and by increased symmetries. We will
argue that the high density phase has to be interpreted as chirally restored
one. The arguments are based on the formation of complete chiral multiplets and
the vanishing of the pionic massless Goldstone modes in the high-density
fluctuation spectrum. We show that the restoration of chiral symmetry is common
to any chirally invariant extension of the usual Skyrme model - whether via
higher-order contact terms or via the introduction of stabilizing vector mesons
which act over a finite range. (Talk at the workshop on ``Baryons as Skyrme
Solitons'', Siegen, Germany, Sept. 27-30, 1992)


title: Remarks on the Heavy-Quark Symmetry in the Complex Plane

abstract:
  Hadronic systems built from a heavy quark and a cloud of light quarks and
massless gluons posess the Isgur-Wise symmetry resulting in certain relations
between various form factors. These relations can not be valid in the entire
complex plane. We identify contributions which unavoidably violate strongly the
symmetry in the time-like domain near thresholds. A possible connection with
the heavy-quark phenomenology is discussed in brief.


title: K and B Physics: a way beyond the Standard Model

abstract:
  I review some aspects of $K$ and $B$ physics both in the context of the
standard model and in some cases in a scenario which is rather different from
the standard model. I discuss, in particular, where we are likely to see
deviations from the standard model in the near future before new colliders are
built.


title: Conference Summary

abstract:
  Talk presented at the XXVI International Conference on High Energy Physics,
Dallas, Texas, August, 12, 1992.


title: A New Anomaly Matching Condition?

abstract:
  We formulate ``Witten'' matching conditions for confining gauge theories. The
conditions are analogous to 't Hooft's, but involve Witten's global SU(2)
anomaly. Using a group theoretic result of Geng, Marshak, Zhao and Okubo, we
show that if the fourth homotopy group of the flavor group $H$ is trivial
($\Pi_4(H) = 0$) then realizations of massless composite fermions that satisfy
the 't Hooft conditions also satisfy the Witten conditions. If $\Pi_4 (H)$ is
nontrivial, the new matching conditions can yield additional information about
the low energy spectrum of the theory. We give a simple physical proof of Geng,
et. al.'s result.


title: Chiral Symmetry and Parity--Violating Meson--Nucleon Vertices

abstract:
  In this lecture, I review progress made in the calculations of the
parity-violating meson-nucleon interaction regions. The underlying framework is
the topological chiral soliton model of the nucleon. Emphasis is put on the
computation of theoretically and experimentally accessible nuclear parity
violating observables. I stress the importance of the interplay of strong and
weak interactions which makes this field interesting and challenging. I also
discuss recent developments pointing towards the importance of strange quark
admixtures in the proton wave function. (Invited talk presented at the Workshop
on ``Baryons as Skyrme Solitons'', Siegen, September, 1992. For figures,
contact author)


title: Long Range Forces from Two Neutrino Exchange Revisited

abstract:
  The exchange of two massless neutrinos gives rise to a long range force which
couples to weakly charged matter. As has been noted previously in the
literature, the potential for this force is $\VN \propto G_{F}^2 / r^5$ with
monopole-monople, spin-spin and more complicated interactions. Unfortunately,
this is far too small to be observed in present day experiments. We calculate
$\VN$ explicitly in the electroweak theory, and show that under very general
assumptions forces arising from the exchange of two massless fermions can at
best yield $1 / r^5$ potentials.


title: Two-loop corrections to the Isgur-Wise function in QCD sum rules

abstract:
  We complete the QCD sum rule analysis of the Isgur Wise form factor
$\xi(v\cdot v')$ at next-to-leading order in renormalization-group improved
perturbation theory. To this end, the exact result for the two-loop corrections
to the perturbative contribution is derived using the heavy quark effective
theory. Several techniques for the evaluation of two-loop integrals involving
two different types of heavy quark propagators are discussed in detail, among
them the methods of integration by parts and differential equations. The
order-$\alpha_s$ corrections to the Isgur-Wise function turn out to be small
and well under control. At large recoil, they tend to decrease the form factor
by $5-10\%$.


title: Kinetics of Sub-Critical Bubbles and the Electroweak Transition

abstract:
  We investigate the role of large amplitude sub-critical thermal fluctuations
in the dynamics of first order phase transitions. In particular, we obtain a
kinetic equation for the number density of sub-critical fluctuations of the
broken-symmetric phase within the symmetric phase, modeled as spherical
bubbles, and solve it analytically for temperatures above the critical
temperature. We study the approach to equilibrium and obtain the equilibrium
distribution of sub-critical bubbles of the unstable phase by examining three
possible mechanisms responsible for their removal; their shrinking, their
coupling to thermal noise, and by thermal fluctuations of the true vacuum
inside them. We show that for sufficiently strong transitions, either the
shrinking or the coupling to thermal noise dominate the dynamics. As the
strength of the transition weakens we show that sub-critical fluctuations
become progressively more important, as a larger fraction of the total volume
is occupied by the broken-symmetric phase, until the point where our analytical
approach breaks down. Our investigation suggests that pre-transitional
phenomena may considerably change the dynamics of sufficiently weak first-order
transitions. We apply our results to the standard electroweak transition.


title:
The Two-Loop Anomalous Dimension Matrix for $\Delta S=1$ Weak
  Non-Leptonic Decays I: ${\cal O}(\alpha_s^2)$

abstract:
  We calculate the two-loop $10 \times 10$ anomalous dimension matrix ${\cal
O}(\alpha_s^{2})$ involving current-current operators, QCD penguin operators,
and electroweak penguin operators especially relevant for $\Delta S=1$ weak
non-leptonic decays, but also important for $\Delta B=1$ decays. The
calculation is performed in two schemes for $\gamma_{5}$: the dimensional
regularization scheme with anticommuting $\gamma_{5}$ (NDR), and in the 't
Hooft-Veltman scheme. We demonstrate how a direct calculation of diagrams
involving $\gamma_{5}$ in closed fermion loops can be avoided thus allowing a
consistent calculation in the NDR scheme. The compatibility of the results
obtained in the two schemes considered is verified and the properties of the
resulting matrices are discussed. The two-loop corrections are found to be
substantial. The two-loop anomalous dimension matrix ${\cal
O}(\alpha_e\alpha_s)$, required for a consistent inclusion of electroweak
penguin operators, is presented in a subsequent publication.


title:
Higher-Order QCD Corrections to Inclusive Particle Production in p
  anti-p Collisions

abstract:
  Inclusive single-particle production cross sections have been calculated
including higher-order QCD corrections. Transverse-momentum and rapidity
distributions are presented and the scale dependence is studied. The results
are compared with experimental data from the CERN S(p anti-p)S Collider and the
Fermilab Tevatron.


title: QCD results for nucleon Compton scattering

abstract:
  We present QCD results for the exclusive processes $\gamma{\rm
N}\rightarrow\gamma{\rm N}$ ($\rm N=p,\;n$) at large momentum transfer and
compare them to data for the proton. TALK given at DPF meeting, November 10-14,
Fermilab.


title: Cosmological Neutrino Mass Limit Revisited

abstract:
  We consider the equilibration of the 'wrong--helicity' Dirac neutrino states
$\nu_{+}$ and $\overline\nu_{-}$ in the early Universe via weak interactions
and calculate carefully the thermally averaged production rate, taking into
account all the relevant scattering and decay processes. Requiring that the
production rate is less than the Hubble parameter at the onset of QCD phase
transition so that the nucleosynthesis predictions are not contradicted, we
find for $T_{\rm{QCD}}\simeq 200$ MeV the upper limits $m_{\nu_\tau}\lsim 740$
keV and $m_{\nu_\mu}\lsim 480$ keV.


title: On the Self-Consistency of Scale-Setting Methods

abstract:
  We discuss various self-consistency conditions for scale-setting methods. We
show that the widely used Principle of Minimum Sensitivity (PMS) is disfavored
since it does not satisfy these requirements.


title: Dynamical supersymmetry breaking with a large internal dimension

abstract:
  Supersymmetry breaking in string perturbation theory predicts the existence
of a new dimension at the TeV scale. The simplest realization of the minimal
supersymmetric Standard Model in the context of this mechanism has two
important consequences: (i) A natural solution to the $\mu$-problem; (ii) The
absence of quadratic divergences in the cosmological constant, which leads to a
dynamical determination of the supersymmetry breaking and electroweak scale. We
present an explicit example in which the whole particle spectrum is given as a
function of the top quark mass. A generic prediction of this mechanism is the
existence of Kaluza-Klein excitations for gauge bosons and higgses. In
particular the first excitation of the photon could be accessible to future
accelerators and give a clear signal of the proposed mechanism.


title: SO(10) Grand Unification with a Low-Energy $M_R$

abstract:
  Contrary to commonly held belief, we show that one can obtain a low value for
$M_R$, the $SU(2)_R$ breaking scale, in grand unification theories based on
$SO(10)$. This possibility emerges in the supersymmetric version of $SO(10)$
with a judicious choice of Higgs content. The unification scale is found to be
consistent with the constraint from proton decay. This result is first
explicitly demonstrated using the one loop renormalization group equations, and
then a full two loop analysis is carried out.


title: Method for Flavor Tagging in Neutral B Meson Decays

abstract:
  A method is proposed for tagging the flavor of neutral $B$ mesons in the
study of CP-violating decay asymmetries. The method makes use of a possible
difference in interactions in $B \pi$ or $B^* \pi$ systems with isospins 1/2
and 3/2, and would be particularly clean if the $I = 1/2$ systems can be
detected as ``$B^{**}$'' resonances.


title: Electroweak Measurements and Top Quark Mass Limits

abstract:
  The agreement of electroweak measurements with theory places limits on the
masses of the top quark and the $W$ boson. It is shown how these limits arise
and what constraints various measurements (particularly a top quark mass
determination) would provide on the theory. The degree to which present and
future measurements can constrain the Higgs boson mass is examined.


title: Quarkonium and Power Law Potentials

abstract:
  The spectra and decay rates of $c \bar c$ and $b \bar b$ levels are well
described, for the most part, by a power-law potential of the form
$V(r)=\lambda(r^{\alpha}-1)/\alpha+{\rm const.}$, where $\alpha\simeq 0$. The
results of an up-to-date fit to the data on spin-averaged levels are presented.
Results on electric dipole transitions in systems bound by power law potentials
are also presented, with applications to the bottomonium system.


title: Vacuum Decay in Theories with Symmetry Breaking by Radiative Corrections

abstract:
  The standard bounce formalism for calculating the decay rate of a metastable
vacuum cannot be applied to theories in which the symmetry breaking is due to
radiative corrections, because in such theories the tree-level action has no
bounce solutions. In this paper I derive a modified formalism to deal with such
cases. As in the usual case, the bubble nucleation rate may be written in the
form $A e^{-B}$. To leading approximation, $B$ is the bounce action obtained by
replacing the tree-level potential by the leading one-loop approximation to the
effective potential, in agreement with the generally adopted {\it ad hoc}
remedy. The next correction to $B$ (which is proportional to an inverse power
of a small coupling) is given in terms of the next-to-leading term in the
effective potential and the leading correction to the two-derivative term in
the effective action. The corrections beyond these (which may be included in
the prefactor) do not have simple expressions in terms of the effective
potential and the other functions in the effective action. In particular, the
scalar-loop terms which give an imaginary part to the effective potential do
not explicitly appear; the corresponding effects are included in a functional
determinant which gives a manifestly real result for the nucleation rate.


title: Hints within the standard model on m_t and m_H

abstract:
  If one or more otherwise divergent quantities in the standard model are
actually finite, they may be indications of underlying dynamics. In particular,
one-loop finiteness of the m_H renormalization is achieved if m_t^2 \simeq
m_H^2 = (2M_W^2 + M_Z^2)/3.


title: Heavy Meson Masses and Decay Constants

abstract:
  Masses and decay constants of mesons containing a single $c$ or $b$ quark are
described within the framework of heavy-quark symmetry. The $B_s^* - B_s$ and
$\bar B^{*0} - \bar B^0$ mass splittings are found equal to within a fraction
of an MeV. Decay constants of $D$ and $B$ mesons are estimated using isospin
mass splittings in the $D$, $D^*$, $B$, and $B^*$ states to isolate the
electromagnetic hyperfine interaction between quarks. A relation following from
the use of splittings in kaons is also considered.


title: Model of the Quark Mixing Matrix

abstract:
  The structure of the Cabibbo-Kobayashi-Maskawa (CKM) matrix is analyzed from
the standpoint of a composite model. A model is constructed with three families
of quarks, by taking tensor products of sufficient numbers of spin-1/2
representations and imagining the dominant terms in the mass matrix to arise
from spin-spin interactions. Generic results then obtained include the familiar
relation $|V_{us}| = (m_d/m_s)^{1/2} - (m_u/m_c)^{1/2}$, and a less frequently
seen relation $|V_{cb}| = \sqrt{2} [(m_s/m_b) - (m_c/m_t)]$. The magnitudes of
$V_{ub}$ and $V_{td}$ come out naturally to be of the right order. The phase in
the CKM matrix can be put in by hand, but its origin remains obscure.


title: Test for Right-Handed $b$ Quark Decays

abstract:
  Gronau and Wakaizumi have proposed a model in which the dominant $b$ decays
are due to exchange of a new right-handed gauge boson. A test of this model via
the study of polarized $\Lambda_b$ baryons produced in $e^+ e^- \to Z \to
\Lambda_b + X$ is suggested.


title: Explicit Calculation of the Renormalized Singlet Axial Anomaly

abstract:
  A careful and complete discussion is given of the renormalization of the
singlet axial anomaly equation in a vector-like nonabelian gauge theory such as
QCD regularized by ordinary dimensional regularization. Pseudotensorial
structures are treated with the 't Hooft-Veltman prescription. A general
framework for calculations is developed, and subsequently verified by explicit
computations through two loops. This is followed by a discussion of the matrix
elements obtained.


title: Matter Effects in Atmospheric Neutrino Oscillations

abstract:
  The Kamiokande II and IMB data on contained events induced by atmospheric
neutrinos exhibit too low a ratio of muons to electrons, which has been
interpreted as a possible indication of neutrino oscillations. At the same
time, the recent data on upward--going muons in underground detectors have
shown no evidence for neutrino oscillations, strongly limiting the allowed
region of oscillation parameter space. In this paper we confront different
types of neutrino oscillation hypotheses with the experimental results. The
matter effects in $\nu_\mu \leftrightarrow \nu_e$ and in $\nu_\mu
\leftrightarrow \nu_{sterile}$ oscillations are discussed and shown to affect
significantly the upward--going muons.


title:
Two--Loop Anomalous Dimension Matrix for $\Delta S=1$ Weak Non-Leptonic
  Decays II: ${\cal O}(\alpha_e \alpha_s)$

abstract:
  We calculate the $10\times 10$ two--loop anomalous dimension matrix to order
$\ord(\alpha_e \alpha_s)$ in the dimensional regularization scheme with
anticommuting $\gamma_5$ (NDR) which is necessary for the extension of the
$\Delta S=1$ weak Hamiltonian involving electroweak penguins beyond the leading
logarithmic approximation. We demonstrate, how a direct calculation of penguin
diagrams involving $\gamma_5$ in closed fermion loops can be avoided thus
allowing a consistent calculation of two--loop anomalous dimensions in the
simplest renormalization scheme with anticommuting $\gamma_5$ in $D$
dimensions. We give the necessary one--loop finite terms which allow to obtain
the corresponding two--loop anomalous dimension matrix in the HV scheme with
non--anticommuting $\gamma_5$.


title: Light Gluinos in $Z^0$ Decays?

abstract:
  We point out that an apparent discrepancy between the values of
$\alpha_s(M_z)$ as determined from low versus high energy experiments can be
explained if an electrically neutral coloured fermion exists which slows down
the running of the strong coupling constant $\alpha_s$.


title: Using Gluon Fusion to Probe CP Violation in the Higgs Sector

abstract:
  A technique for directly probing CP violation in the Higgs sector of a
multi-doublet model using gluon-gluon collisions at the SSC is reviewed.


title: Searching for the Minimal Supersymmetric Model Higgs Bosons

abstract:
  A brief overview of the prospects for detecting the Higgs bosons of the
Minimal Supersymmetric Model at future colliders is presented.


title: Flipped Heavy Neutrinos from the Solar Neutrino Problem to Baryogenesis

abstract:
  We discuss baryogenesis using the flipped $SU(5)$ model for lepton mass
matrices. We show that the generalized see-saw mechanism in this model can not
only provide MSW neutrino mixing suitable for solving the solar neutrino
problem, and supply a hot dark matter candidate ($\nu_\tau$) with mass
$0(10)eV$ as indicated by recent COBE results, but can also naturally account
for the baryon asymmetry of the universe. Heavy singlet neutrino decay
generates a net lepton asymmetry which is subsequently reprocessed by
nonperturbative electroweak interactions. We evaluate the baryon asymmetry so
produced in light of the constraints that the COBE observations put on
inflationary cosmologies, finding it comfortably consistent with observation.


title: Top Width Effects in Soft Gluon Radiation

abstract:
  Soft gluons radiated in top quark production and decay can interfere in a way
that is sensitive to the top width. We show how the width affects the gluon
distribution in $e^+e^- \rightarrow t {\bar t}$ and discuss prospects for
measuring $\Gamma$ from gluons radiated near $\tt$ threshold.


title:
Response to Brodsky and Lu's Letter "On the Self-Consistency of
  Scale-Setting Methods

abstract:
  The claim that the Principle of Minimal Sensitivity is "disfavored" because
it does not satisfy certain "self-consistency requirements" is meaningless, and
shows a basic misunderstanding of the renormalization-scheme-dependence
problem.


title:
A test of the equivalence principle by long-baseline
  neutrino-oscillation experiments

abstract:
  We show that a breakdown of the universality of the gravitational couplings
to different neutrino flavors can be tested in long-baseline
neutrino-oscillation experiments. In particular we have analyzed in detail a
proposed experiment at SOUDAN 2 with $\nu_\mu$ beams from the Fermilab Main
Injector. It turns out that we can study both masses of neutrinos and such a
breakdown with sensitivity to the order of $10^{-14}$ by investigating the
energy spectrum of the resulting muons.


title: Effective Potentials in QCD and Chiral Symmetry Breaking

abstract:
  We consider chiral symmetry breaking through nontrivial vacuum structure with
an explicit construct for the vacuum with quark antiquark condensates in QCD
with Coulomb gauge for different phenomenological potentials. The dimensional
parameter for the condensate function gets related to $<{\bar \psi }\psi>$ of
Shifman, Vainshtein and Zakharov. We then relate the condensate function to the
wave function of pion as a Goldstone mode. This simultaneously yields the pion
also as a quark antiquark bound state as a localised zero mode of vacuum. We
then calculate different pionic properties using the wave function as obtained
from the vacuum structure. (to appear in Z. Phys. C)


title: q\bar q$ Bound States in the Bethe-Salpeter Formalism

abstract:
  We solve the Bethe-Salpeter equation in order to determine the spectrum of
pseudoscalar and vector meson bound states for light as well as heavy quarks.
The fermion propagators are obtained by solving the Schwinger-Dyson equation
consistently with the Bethe-Salpeter equation, a procedure necessary for
demonstrating the Goldstone nature of the pion in the chiral limit. Our results
agree qualitatively and quantitatively with expectations both from current
algebra for light quarks and from composite models for heavy quarks.}


title:
Multiple $W_L$ Production from Inelastic $W_L W_L$ Scattering at
  $\sqrt{\hat{s}} \gg M_H$

abstract:
  We explore the inelastic production of multiple longitudinal weak bosons as a
manifestation of a strongly interacting symmetry breaking sector. By analogy
with QCD, final states with large multiplicities are expected to occur not far
above the energy scale of the lowest resonances of the underlying strong
theory. We consider the feasibility of observing such phenomena in the
environment of a very high energy hadron collider.


title:
Exclusive Decays $B \rightarrow K \psi , B \rightarrow K^* \psi $ using
  Heavy Quark Symmetries

abstract:
  We use the new symmetries in the heavy quark limit to calculate the exclusive
B-decays $B \rightarrow K \psi ({\psi}^{\prime})$ and $B \rightarrow K^* \psi
({\psi}^{\prime})$. The estimated decay rates are compared with experimental
values. We also estimate rare $B \rightarrow K^* \gamma $ decay rate, based on
these experimental data and heavy quark symmetry.


title: QCD Corrected $1/m_b$ Contributions to $B\bbar$--Mixixng

abstract:
  We calculate the QCD corrected effective Hamiltonian for $B\bbar$--Mixing in
heavy quark effective theory including corrections of the order $\Lambda_{QCD}
/ m_b$. The matrix elements of the subleading operators are estimated using the
vacuum insertion assumption. We show that the major part of the subleading
corrections may be absorbed into the heavy meson decay constant $f_B$; the
remaining corrections are only due to QCD effects and give an enhancement of
$\Delta M$ of 5\%.


title:
On the Analytic Structure of the Self-Energy for Massive Gauge Bosons at
  Finite Temperature

abstract:
  We show that the one-loop self-energy at finite temperature has a unique
limit as the external momentum $p_\mu\rightarrow 0$ {\it if} the loop involves
propagators with distinct masses. This naturally arises in theories involving
particles with different masses as is demonstrated for a toy model of two
scalars as well as in a $U(1)$ Higgs theory. We show that, in spontaneously
broken gauge theories, this observation nonetheless does not affect the
difference between the Debye and plasmon masses, which are often thought of as
the $(p_0=0, \vec{p}\to 0)$ and $(p_0\to 0,\vec{p}=0)$ limits of the
self-energy.


title: Supersqueezed States

abstract:
  We derive the supersqueeze operator for the supersymmetric harmonic
oscillator, using Baker-Campbell-Hausdorff relations for the supergroup
OSP(2/2). Combining this with the previously obtained superdisplacement
operator, we derive the supersqueezed states. These are the supersymmetric
generalization of the squeezed states of the harmonic oscillator.


title: Interpretation of the Color Transparency Experiments

abstract:
  We argue that the experimentally measured color transparency ratio is
directly related to the interacting hadron wave function at small transverse
separation, $b^2<1/Q^2$. We show that the present experimental data is
consistent with pure scaling behavior of the hadron-hadron and lepton-hadron
scattering inside the nuclear medium.


title: Infrared Corrections to the Top Quark Width

abstract:
  We present a nonperturbative analysis of the top quark propagator using the
Schwinger Dyson equation in the ladder approximation including both the
electroweak as well as the infrared QCD effects.
  We find that the infrared effects are negligible only for top mass larger
than about 250 GeV.


title: Tightly Bound Composite Higgs

abstract:
  We explain general features of the tightly bound composite Higgs models
proposed in recent years; walking technicolor, strong ETC technicolor, and a
top quark condensate, etc.. These models are all characterized by the large
anomalous dimension due to nontrivial short distance dynamics in the gauged
Nambu-Jona-Lasinio models (gauge theories plus four-fermion interactions).


title: QCD Corrections to Higgs Boson Production

abstract:
  We discuss the ${\cal O}(\alpha_s)$
  QCD radiative corrections to Higgs boson production in the limit in which the
top quark is much heavier than the Higgs boson. The subleading corrections, of
${\cal O} (\alpha_s M_H^2/M_{\rm top}^2)$, are presented for the decay
$H\rightarrow \gamma\gamma$ and shown to be small.


title:
Global Constraints of Gauss' Law and the Solution to the Strong CP
  Problem

abstract:
  This is a brief review on the work done recently. It is shown that the global
constraints of Gauss' law ensure that the vacuum angle must be quantized in
gauge theories with magnetic monopoles. Our quantization rule is given as
$\theta=0$, or $\theta=2\pi N/n~ (n\neq 0)$ with integer n being the relevant
topological charge of the magnetic monopole and N is an unfixed integer in this
approach. This theoretically confirms further the conclusion originally
proposed by the author$^1$ that the strong CP problem can be solved due to the
existence of magnetic monopoles, the fact that the strong CP-violation can be
only so small or vanishing may imply the existence of magnetic monopoles, and
the universe is open.


title: $\epsilon^{\prime}/\epsilon$ at the next-to-leading order in QCD and QED

abstract:
  We present a new calculation of the CP violation parameter
$\epsilon^{\prime}/ \epsilon$. The results reported in this paper have been
obtained by using the $\Delta S=1$ effective Hamiltonian computed at the
next-to-leading order, including QCD and QED penguins. The matrix elements of
the relevant operators have been taken from lattice QCD, at a scale $\mu=2$
GeV. At this relatively large scale, the perturbative matching between the
relevant operators and the corresponding coefficients is quite reliable.
  The effect of the next-to-leading corrections is to lower the prediction
obtained at the leading order, thus favouring the experimental result of E731.
We analyze different contributions to the final result and compare the leading
and next-to-leading cases.


title: Do Solar Neutrino Experiments Imply New Physics?

abstract:
  None of the 1000 solar models in a full Monte Carlo simulation is consistent
with the results of the chlorine or the Kamiokande experiments. Even if the
solar models are forced artifically to have a \b8 neutrino flux in agreeement
with the Kamiokande experiment, none of the fudged models agrees with the
chlorine observations. The GALLEX and SAGE experiments, which currently have
large statistical uncertainties, differ from the predictions of the standard
solar model by $2 \sigma$ and $3 \sigma$, respectively.


title:
An Analysis of the Decay $B \rightarrow D^* X \ell \bar\nu_\ell$ with
  Predictions from Heavy Quark and Chiral Symmetry

abstract:
  This paper considers the implications of the heavy quark and chiral
symmetries for the semi-leptonic decay $B \rightarrow D^* X \ell \bar
\nu_\ell$. The general kinematic analysis for decays of the form {\sl
pseudoscalar meson $\rightarrow$ vector meson $+$ pseudoscalar meson $+$ lepton
$+$ anti-lepton} is presented. This formalism is applied to the above exclusive
decay which allows the differential decay rate to be expressed in a form that
is ideally suited for the experimental determination of the different form
factors for the process through angular distribution measurements. Heavy quark
and chiral symmetry predictions for the form factors are presented, and the
differential decay rate is calculated in the kinematic region where chiral
perturbation theory is valid.


title: Particle production in the central rapidity region

abstract:
  We study pair production from a strong electric field in boost-invariant
coordinates as a simple model for the central rapidity region of a heavy-ion
collision. We derive and solve the renormalized equations for the time
evolution of the mean electric field and current of the produced particles,
when the field is taken to be a function only of the fluid proper time $\tau =
\sqrt{t^2-z^2}$. We find that a relativistic transport theory with a Schwinger
source term modified to take Pauli blocking (or Bose enhancement) into account
gives a good description of the numerical solution to the field equations. We
also compute the renormalized energy-momentum tensor of the produced particles
and compare the effective pressure, energy and entropy density to that expected
from hydrodynamic models of energy and momentum flow of the plasma.


title: On the CP-odd Nucleon Potential

abstract:
  The CP-odd nucleon potential for different models of CP violation in the one
meson exchange approximation is studied. It is shown that the main contribution
is due to the $\pi$-meson exchange which leads to a simple one parameter CP-odd
nucleon potential.


title: Renormalization in the Gauged Nambu--Jona-Lasinio Model

abstract:
  Based on the Cornwall-Jackiw-Tomboulis effective potential, we extensively
study nonperturbative renormalization of the gauged Nambu-Jona-Lasinio model in
the ladder approximation with standing gauge coupling. Although the pure
Nambu-Jona-Lasinio model is not renormalizable, presence of the gauge
interaction makes it possible that the theory is renormalized as an interacting
continuum theory at the critical line in the ladder approximation. Extra higher
dimensional operators (``counter terms'') are not needed for the theory to be
renormalized. By virtue of the effective potential approach, the
renormalization (``symmetric renormalization'') is performed in a
phase-independent manner both for the symmetric and the spontaneously broken
phases of the chiral symmetry. We explicitly obtain $\beta$ function having a
nontrivial ultraviolet fixed line for the renormalized coupling as well as the
bare one. In both phases the anomalous dimension is very large ($ \ge 1$)
without discontinuity across the fixed line. Operator product expansion is
explicitly constructed, which is consistent with the large anomalous dimension
owing to the appearance of the nontrivial extra power behavior in the Wilson
coefficient for the unit operator. The symmetric renormalization breaks down at
the critical gauge coupling, which is cured by the generalized renormalization
scheme (``$\tM$-dependent renormalization''). Also emphasized is the formal
resemblance to the four-fermion theory in less than four dimensions which is
renormalizable in $1/N$ expansion.


title:
A Non-Commutative Geometric Approach to Left-Right Symmetric Weak
  Interactions

abstract:
  By combining the generalized exterior algebra of forms over a noncommutative
algebra with the gauging of discrete directions and the associated Higgs
fields, we consider the construction of the bosonic sector of left-right
symmetric models of the form $SU(2)_{L}\otimes SU(2)_{R}\otimes U(1)$. We see
that within this formalism maximal use can be made of the gauge connection
associated with the non-commutative graded algebra.


title: Strangeness Conservation in Hot Nuclear Fireballs

abstract:
  A constraint between thermal fireball parameters arises from the requirement
that the balance of strangeness in a fireball is (nearly) zero. We study the
impact of this constraint on (multi-)strange (anti-)baryon multiplicities and
compare the hadron gas and quark-gluon plasma predictions. We explore the
relation between the entropy content and particle multiplicities and show that
the data are compatible with the quark-gluon plasma hypothesis, but appear to
be inconsistent with the picture of an equilibrated hadron gas fireball. We
consider the implications of the results on the dynamics of evolution and decay
of the particle source.


title:
Non Linear Realizations of $SU(2)\times U(1)$ in the MSSM: Model
  Independent Analysis and $g-2$ of $W$ Bosons

abstract:
  We perform a model-independent analysis of the spontaneously broken phase of
an $SU(2)\times U(1)$ supersymmetric gauge theory, by using a non-linear
parametrization of the Goldstone sector of the theory. The non-linear variables
correspond to an $SL(2,C)$ superfield matrix in terms of which a non-linear
Lagrangian can be constructed, and the pattern of supersymmetry breaking
investigated. The supersymmetric order parameter is the V.E.V. of the neutral
pseudo-Goldstone boson. Some applications of this technique are considered, in
relation to the minimal supersymmetric standard model, and to determine the
$g-2$ of the $W$-bosons in the limit of large top mass.


title: Diffractive Hard Scattering with a Coherent Pomeron

abstract:
  Diffractive scattering involves exchange of a Pomeron to make a rapidity gap.
It is normally assumed that to get a hard scattering in diffraction, one may
treat the Pomeron as an ordinary particle, which has distributions of gluons
and quarks. We show that this is not so: When we use perturbative QCD, there is
a breakdown of the factorization theorem. The whole Pomeron can initiate the
hard scattering, even though it is not point-like. Qualitatively, but not
quantitatively, this gives the same effect as a delta function term in the
gluon density in a Pomeron.


title: Electroweak Symmetry Breaking at the SSC and LHC

abstract:
  In this talk we survey the SSC and LHC signals and backgrounds for the
physics of electroweak symmetry breaking. We study the process $pp \rightarrow
WWX$ and compute the rate for the ``gold-plated'' signals $W^\pm \rightarrow
\ell^\pm \nu$ and $Z \rightarrow \ell^+\ell^-$ $(\ell = e,\mu)$ for a wide
variety of models. We use a forward jet tag and central jet veto to suppress
the standard-model backgrounds. In this way we estimate the SSC and LHC
sensitivities to the physics of electroweak symmetry breaking.


title:
Dynamics of the Cosmological Quark-Hadron Transition in a Matter
  Dominated Universe: Distribution and Evolution of Baryon Inhomogeneities

abstract:
  We study the dynamics of the quark-hadron transition for a scenario in which
the Universe is matter dominated and a large amount of entropy is generated by
decaying particles of mass 1--10 TeV, as suggested by a large class of
superstring--inspired models. We estimate the nucleation rate and compute the
mean separation between baryon fluctuations generated during the transition
following their evolution up to the onset of primordial nucleosyntheisis.


abstract:
  Constrained Instanton and Baryon Number Non--Conservation at High Energies,
P.G.Silvestrov, BUDKERINP 92--92. The total cross-section for baryon number
violating processes at high energies is usually parametrized as
$\sigma_{total}\propto\exp(\frac{4\pi}{\alpha} F(\varepsilon))$, where
$\varepsilon =\sqrt{s}/E_0 , \,\, E_0 = \sqrt{6} \pi m_w/\alpha$. In the
present paper the third nontrivial term of the expansion \[ F(\varepsilon)=
-1+\frac{9}{8}\varepsilon^{4/3} -\frac{9}{16}\varepsilon^2 -\frac{9}{32} \left(
\frac{m_h}{m_w}\right)^2 \varepsilon^{8/3}\log\left(
\frac{1}{3\varepsilon}\left( \frac{2m_w}{\gamma m_h}\right)^2 \right) +
O(\varepsilon^{8/3}) \] is obtained.The unknown corrections to $F(\varepsilon)$
are expected to be of the order of $\varepsilon^{8/3}$, but have neither
$(m_h/m_w)^2$, nor $\log(\varepsilon)$ enhancement. The total cross-section is
extremely sensitive to the value of single Instanton action. The correction to
Instanton action $\triangle S\sim (m\rho)^4 \log(m\rho)/g^2$ is found ($\rho$
is the Instanton radius). For sufficiently heavy Higgs boson the $\rho$
-dependent part of the Instanton action is changed drastically. In this case
even the leading contribution to $F(\varepsilon)$, responsible for a growth of
cross-section due to the multiple production of classical W-bosons, is changed:
\[ F(\varepsilon)=-1+ \frac{9}{8}\left( \frac{2}{3} \right)^{2/3}
\varepsilon^{4/3} +\ldots \,\, , \,\, \varepsilon\ll 1\ll \varepsilon \left(
\frac{m_h}{m_w} \right)^{3/2} \,\, . \]


title: Aspects of the Electroweak Phase Transition

abstract:
  Presented at the 1992 Meeting of the DPF, Fermilab. The electroweak phase
transition is reviewed in light of some recent developments. Emphasis is on the
issue whether the transition is first or second order and its possible role in
the generation of the baryon asymmetry of the universe.


title: Recent Progress in Lattice QCD

abstract:
  I give a brief overview of the status of lattice QCD, concentrating on topics
relevant to phenomenology. I discuss the calculation of the light quark
spectrum, the lattice prediction of $\alpha_\MS(M_Z)$, and the calculation of
$f_B$.


title:
Non-Standard Physics and Nucleon Strangeness in Low-Energy PV Electron
  Scattering

abstract:
  Contributions from physics beyond the Standard Model, strange quarks in the
nucleon, and nuclear structure effects to the left-right asymmetry measured in
parity-violating (PV) electron scattering from $\nuc{12}{C}$ and the proton are
discussed. It is shown how lack of knowledge of the distribution of strange
quarks in the nucleon, as well as theoretical uncertainties associated with
higher-order dispersion amplitudes and nuclear isospin-mixing, enter the
extraction of new limits on the electroweak parameters $S$ and $T$ from these
PV observables. It is found that a series of elastic PV electron scattering
measurements using $^{4}$He could significantly constrain the $s$-quark
electric form factor if other theoretical issues are resolved. Such constraints
would reduce the associated form factor uncertainty in the carbon and proton
asymmetries below a level needed to permit extraction of interesting low-energy
constraints on $S$ and $T$ from these observables. For comparison, the much
smaller scale of $s$-quark contributions to the weak charge measured in atomic
PV is quantified. It is likely that only in the case of heavy muonic atoms
could nucleon strangeness enter the weak charge at an observable level.


title: Family Symmetry, Gravity, and the Strong CP Problem

abstract:
  We show how in a class of models Peccei--Quinn symmetry can be realized as an
automatic consequence of a gauged $U(1)$ family symmetry. These models provide
a solution to the strong CP problem either via a massless $u$--quark or via the
DFSZ invisible axion. The local family symmetry protects against potentially
large corrections to $\overline{\theta} $ induced by quantum gravitational
effects. In a supersymmetric extension, the `$\mu$--problem' is shown to have a
natural solution in the context of gravitationally induced operators. We also
present a plausible mechanism which can explain the inter--generational mass
hierarchy in such a context.


title: Radiative Decays of the P-Wave Charmed Mesons

abstract: Minor (mainly numerical) corrections.


title: Hamiltonian Effective Potential

abstract:
  A Hamiltonian effective potential (the logarithm of the square of the wave
functional) is defined and calculated at the tree and one loop levels in a
$\phi^4$ scalar field theory. The loop expansion for eigenfunctionals is
equivalent to the combination of WKB expansion and an expansion around constant
field configurations. The results are compared with those obtained from the
Lagrangian effective potential. While at tree level the results from the two
methods coincide, at one loop level they differ. Our result at one loop level
is that the reflection symmetry is not broken at $m^2\geq0$.


title: Numerical study of radiative corrections in the low $Q^2$ region at HERA

abstract:
  A detailed numerical study of radiative corrections in the low $Q^2$ region
at the HERA $ep$ collider was performed. The specific case of the total
photoproduction cross section measurement was taken as an example. Two
different programs, TERAD91 and HERACLES4.2, were used to get an estimation of
the size of radiative effects. It was found that radiative corrections can be
quite large in some points of the space of leptonic $(x,y)$ variables. However,
after imposing experimentally feasible cuts on the radiated photon and the
hadronic final state one gets corrections at the level of a few per cent.


title:
\cl{\bf $\tau\rightarrow\mu\mu{\bar\mu}$ and $\tau\rightarrow\mu e{\bar
  e}$ Decays in String Models with $\e6$ Symmetry

abstract:
  A detailed analysis on the rare $\tau$ decay {\it via} $\taumue$ and
$\taumus$ in the string models with $\e6$ symmetry is reported. It is found
that $\Gamma(\taumue)\sim(6-7)\Gamma(\taumus)$ and these rates are in general
about 1000 times less than that of $\Gamma(\mu\rightarrow e\gamma)$. It is also
found that the out-going muon in $\taumue$ is almost 100\% right-handed
polarized and the out-going electrons would be predominately parallel to each
other. These decay processes may be accessible at the SSC.


title:
Hydrodynamic Stability Analysis of Burning Bubbles in Electroweak Theory
  and in QCD

abstract:
  Assuming that the electroweak and QCD phase transitions are first order, upon
supercooling, bubbles of the new phase appear. These bubbles grow to
macroscopic sizes compared to the natural scales associated with the Compton
wavelengths of particle excitations. They propagate by burning the old phase
into the new phase at the surface of the bubble. We study the hydrodynamic
stability of the burning and find that for the velocities of interest for
cosmology in the electroweak phase transition, the shape of the bubble wall is
stable under hydrodynamic perturbations. Bubbles formed in the cosmological QCD
phase transition are found to be a borderline case between stability and
instability.


title: The Pion Cloud in Quenched QCD

abstract:
  Diagrammatic methods and Large $N_c$ QCD are used to argue that the nucleon
as calculated in quenched QCD contains physics which can be ascribed to the
pion cloud of the nucleon. In particular, it is argued that the physics
corresponding to one-pion loops in chiral perturbation theory are included in
the quenched approximation.


title: Chiral Perturbation Theory Analysis of the Baryon Magnetic Moments

abstract:
  Nonanalytic $m_q^{1/2}$ and $m_q\ln m_q$ chiral corrections to the baryon
magnetic moments are computed. The calculation includes contributions from both
intermediate octet and decuplet baryon states. Unlike the one-loop
contributions to the baryon axial currents and masses, the contribution from
decuplet intermediate states does not partially cancel that from octet
intermediate states. The fit to the observed magnetic moments including
$m_q^{1/2}$ corrections is found to be much worse than the tree level SU(3) fit
if values for the baryon-pion axial coupling constants obtained from a tree
level extraction are used. Using the axial coupling constant values extracted
at one loop results in a better fit to the magnetic moments than the tree level
SU(3) fit. There are three linear relations amongst the magnetic moments when
$m_q^{1/2}$ corrections are included, and one relation including $m_q^{1/2}$,
$m_q\ln m_q$ and $m_q$ corrections. These relations are independent of the
axial coupling constants of the baryons and agree well with experiment.


title: A QCD ``Manifesto'' on Inclusive Decays of Beauty and Charm

abstract:
  A selfconsistent treatment of nonperturbative effects in inclusive
nonleptonic and semileptonic decays of beauty and charm hadrons is presented.
It is illustrated by calculating semileptonic branching ratios, lifetime
ratios, radiative decay rates and the lepton spectra in semileptonic decays.


title: On the Statistics of CMB Fluctuations Induced by Topological Defects

abstract:
  We use the analytical model recently introduced in Ref. \cite{lp92}, to
investigate the statistics of temperature fluctuations on the cosmic microwave
background (CMB), induced by topological defects. The cases of cosmic strings
and textures are studied. We derive analytically the characteristic function of
the probability distribution for ${\delta T}\over T$ and use it to obtain the
lowest twelve moments including the skewness and the kurtosis. The distribution
function is also obtained and it is compared with the Gaussian distribution
thus identifying long non-Gaussian tails. We show that for both cosmic strings
and textures all odd moments (including skewness) vanish while the relative
deviation from the Gaussian for even moments increases with the order of the
moment. The non-Gaussian signatures of textures, derived from the distribution
function and the moments, are found to be much more prominent than the
corresponding signatures for strings. We discuss the physical origin of this
result.


title: One Loop Effects of Non-Standard Triple Gauge Boson Vertices

abstract:
  Low energy effects of generic extensions of the Standard Model can be
comprehensively parametrized in terms of higher dimensional effective
operators. After the success of all the recent precission tests on the Standard
Model, we argue that any sensible description of these extensions at the
Z-scale must be stable under higher order quantum corrections. The imposition
of $SU(2)_L \times U(1)_Y$ gauge invariance seems to be the simplest and most
natural way to fulfill this requirement. With this assumption, all the possible
deviations from the standard triple gauge boson vertices can be consistently
parametrized in terms of a finite set of gauge invariant operators. We deal
here with those operators that do not give any tree level effect on present
experimental observables and constrain them by computing their effects at the
one-loop level. We conclude that for a light Higgs boson, the direct
measurement at LEP200 can improve present bounds on these "blind directions",
while for a heavy Higgs it is most unlikely to provide any new information.


title: Electromagnetic Mass Splittings in Heavy Mesons

abstract:
  The electromagnetic contribution to the isomultiplet mass splittings of heavy
mesons is reanalyzed within the framework of the heavy mass expansion.
  It is shown that the leading term in the expansion is given to a good
approximation by the elastic term. $1/m_{Q}$-corrections can only be estimated,
the main source of uncertainty now being inelastic contributions. The
$1/m_{Q}$-corrections to the elastic term turn out to be relatively small in
both D and B pseudoscalar mesons.


title: Applying Optimized Perturbation Theory to QCD at Low Energies

abstract:
  We discuss the use of the optimization procedure based on the Principle of
Minimal Sensitivity to the third-order calculation of {\mbox{${R_{e^+e^-}}$}}.
The effective coupling constant remains finite allowing us to apply the
Poggio-Quinn-Weinberg smearing method down to energies below 1 GeV, where we
find good agreement between theory and experiment. The couplant freezes to a
value of $\alpha_s/\pi = 0.26$ at zero energy which is in remarkable
concordance with values obtained phenomenologically.


title:
The First Gauge Theory of Weak Interactions and the Prediction of Weak
  Neutral Currents

abstract:
  The three theoretical and historical components of the Standard Model are the
exact chiral gauge theory of weak interactions, electroweak unification, and
the Higgs mechanism for spontaneous symmetry breaking. I put into historical
perspective my 1958 invention of the first gauge theory of weak interactions,
predicting weak neutral currents, and show how the fundamental differences
between global and gauge symmetries and between partial flavour and exact gauge
symmetries, emerged in the strong and weak interactions. Although
renormalizability is necessary for theoretical consistency, electroweak
unification was not necessary, in principle. An interesting difference appears
between the $\sin^2{\theta_W}=0$ limit of the electroweak theory and the
original $SU(2)_W$ gauge theory of weak interactions. While the electroweak
mixing angle might have had any value (including zero), historically the value
$\sin^2{\theta_W} \sim 0.3$ actually observed in weak neutral currents gave
circumstantial support for the Standard Model and stimulated the search for
$W-$ and $Z-$mesons.


title: FSI phases and CP asymmetries in beauty: QCD point of view

abstract:
  Inclusive and exclusive decays of heavy flavours look quite different from a
theoretical viewpoint. We argue that inclusive decays can be treated
quantitatively and report on the calculation of the perturbative corrections to
the Final State Interaction phases in connection to their impact on effects of
CP violation.


title: P and T Violation From Certain Dimension Eight Weinberg Operators

abstract:
  Dimension eight operators of the Weinberg type have been shown to give
important contributions to CP violating phenomena, such as the electric dipole
moment of the neutron. In this note we show how operators related to these (and
expected to occur on equal footing) can give rise to time-reversal violating
phenomena such as atomic electric dipole moments. We also estimate the induced
parity violating phenomena such as small ``wrong'' parity admixtures in atomic
states and find that they are negligible. Uses harvmac.tex and epsf.tex; one
figure submitted as a uuencoded, compressed EPS file.


title:
The Effective Potential and First-Order Phase Transitions: Beyond
  Leading Order

abstract:
  Scenarios for electroweak baryogenesis require an understanding of the
effective potential at finite temperature near a first-order electroweak phase
transition. Working in Landau gauge, we present a calculation of the dominant
two-loop corrections to the ring-improved one-loop potential in the formal
limit $g^4 \ll \lambda \ll g^2$, where $\lambda$ is the Higgs self-coupling and
$g$ is the electroweak coupling. The limit $\lambda \ll g^2$ ensures that the
phase transition is significantly first-order, and the limit $g^4 \ll \lambda$
allows us to use high-temperature expansions. We find corrections from 20 to
40\% at Higgs masses relevant to the bound computed for baryogenesis in the
Minimal Standard Model. Though our numerical results seem to still rule out
Minimal Standard Model baryogenesis, this conclusion is not airtight because
the loop expansion is only marginal when corrections are as big as 40\%. We
also discuss why super-daisy approximations do not correctly compute these
corrections.


title: Exotic QQ\qbar\qbar States in QCD

abstract:
  We show that QCD contains stable four-quark QQ\qbar\qbar hadronic states in
the limit where the heavy quark mass goes to infinity. (Here Q denotes a heavy
quark, \qbar a light antiquark and the stability refers only to the strong
interactions.) The long range binding potential is due to one pion exchange
between ground state Q\qbar mesons, and is computed using chiral perturbation
theory. For the Q=b, this long range potential may be sufficiently attractive
to produce a weakly bound two meson state.


title: The Five Gluon Amplitude and One-Loop Integrals

abstract:
  We review the conventional field theory description of the string motivated
technique. This technique is applied to the one-loop five-gluon amplitude. To
evaluate the amplitude a general method for computing dimensionally regulated
one-loop integrals is outlined including results for one-loop integrals
required for the pentagon diagram and beyond. Finally, two five-gluon helicity
amplitudes are given.


title:
The chiral anomaly and electromagnetic pion decay in effective quark
  models

abstract:
  Within renormalizable theories the triangle diagram correctly reproduces the
lifetime of the neutral pion $\pi ^0$. However, effective relativistic quark
models which contain a second scale besides the quark mass seem unable to give
the correct value for this quantity. In the Instanton Liquid Model this second
scale is the mean instanton radius, in the NJL model it is the cutoff. The role
of the cutoff within a path integral derivation of the chiral anomaly is
clarified and the importance of higher order terms contributing to the $\pi ^0$
decay width and other anomalous processes is pointed out.


title:
Minkowski Space Non-Abelian Classical Solutions with Non-Integer Winding
  Number Change

abstract:
  Working in a spherically symmetric ansatz in Minkowski space we discover new
solutions to the classical equations of motion of pure $SU(2)$ gauge theory.
These solutions represent spherical shells of energy which at early times move
inward near the speed of light, excite the region of space around the origin at
intermediate times and move outward at late times. The solutions change the
winding number in bounded regions centered at the origin by non-integer
amounts. They also produce non-integer topological charge in these regions. We
show that the previously discovered solutions of Luscher and Schechter also
have these properties.


title: Cosmological and Astrophysical Bounds on Neutrino Masses and Lifetimes

abstract:
  The best upper bounds on the masses of stable and unstable light neutrinos
derive from the upper bound on the total mass density, as inferred from the
lower limit $t_0> 13$ Gyr on the dynamical age of the Universe: If the Universe
is matter-dominated, $m_\nu<35(23)\times$ max$ [1, (t_0/\tau_\nu)^{1/2}]$ eV,
according as a cosmological constant is (is not) allowed. The best constraints
on the radiative decay of light neutrinos derive from the failure to observe
prompt gamma rays accompanying the neutrinos from Supernova 1987A: For any
$m_{\nu} > 630$ eV, this provides a stronger bound on the neutrino transition
moment than that obtained from red giants or white dwarfs. For $m_\nu > 250$ eV
or $\tau_\nu < t_{rec}\sim 7\times 10^{12}$ sec, the upper limit on the
radiative branching ratio is even smaller than that obtained from the limits on
$\mu$-distortion of the cosmic background radiation. Our results improve on
earlier cosmological and radiative decay constraints by an overall factor
twenty, and allow neutrinos more massive than 35 eV, only if they decay
overwhelmingly into singlet majorons or other new particles.


title: Theoretical Implications of the Combined Solar Neutrino Observations

abstract:
  Constraints on the core temperature of the Sun and on neutrino-oscillation
parameters are obtained by comparing the combined Homestake, Kamiokande, SAGE
and GALLEX solar neutrino data with Standard Solar Models (SSM) and with
non-standard solar models parameterized by a phenomenological central
temperature ($T_c$). If the Sun is 2\% cooler or 3\% warmer than predicted by
SSMs, the MSW parameters we determine are consistent with different grand
unified theories.


title:
Polarization and Handedness in Tau -> 3 Pi + Neutrino Decay Produced in
  e+e- Annihilations

abstract:
  We discuss the concept of handedness applied to $\tau$ production in $e^+e^-$
annihilations with $\tau$ decaying into $a_1\nu_\tau \to 3\pi\nu_\tau$. The
$a_1\to 3\pi$ decay is particularly interesting since it (together with $h_1\to
3\pi$) is the lightest hadronic decay in which the helicity of the initial
state can be determined from the distribution of the final particle momenta.
Thus it is the first example of a helicity self-analysing strong decay, as
$\Lambda\to N\pi$ is for weak decays. Apart from providing a new method for
determining the $\tau$ polarization from the parity conserving part in the weak
decay, this reaction provides a very instructive and useful demonstration of
the handedness asymmetry as a measure of parton polarization. Thus we believe
that experience gained from analyses of handedness in $\tau\to 3\pi\nu_\tau$
decay will be very useful when looking for the similar asymmetry of jet
handedness which can measure quark or gluon polarization.


title:
High Energy Hadronic Helicity Violation: What Helicity Flip Form Factors
  Measure

abstract:
  Orbital angular momentum is crucial for the description of several process at
large momentum transfer in the impulse approximation in perturbative QCD. We
review the mechanism of independent scattering which makes violation of the
helicity conservation rule possible at leading order - and without any need to
flip a quark helicity - in exclusive hadron-hadron reactions. We argue that
helicity flip form factors, which violate the factorization assumptions of
conventional approaches and are classified as ``higher-twist," are nevertheless
calculable to leading order in perturbative QCD when information on non-zero
orbital angular momentum is incorporated.


title: Consistent Quantum Expansion Around Soliton Solutions

abstract:
  I show that a standard application of the semiclassical techniques to 1+1
dimensional field theories, as originally discussed by Dashen, Hasslacher and
Neveu, explicitly violates the Poincare algebra. This problem is traced to the
incorrect regularization of the ultraviolet divergences and can be resolved by
using a different regularization. I further show that in the case of the
doublet solutions in the sine-Gordon theory the semiclassical treatment given
by Dashen, Hasslacher and Neveu leads to ambiguous results which depend on the
choice of the renormalization counterterm. I discuss a consistent weak coupling
expansion which does not suffer from this problem.


title: Inverse Hierarchy Approach to Fermion Masses

abstract:
  The first fermion family might play a special role in understanding the
physics of flavour. This possibility is suggested by the observation that the
up-down splitting within quark families increases with the family number: $
m_u\sim m_d$, $m_c>m_s$, $m_t\gg m_b$. We construct a model that realizes this
feature of the spectrum in a natural way. The inter-family hierarchy is first
generated by radiative phenomena in a sector of heavy isosinglet fermions and
then transferred to quarks by means of a universal seesaw. A crucial role is
played by left-right parity and up-down isotopic symmetry. No family symmetry
is introduced. The model implies $m_u/m_d>$ 0.5 and the Cabibbo angle is forced
to be $\sim\sqrt{m_d/m_s}$. The top quark is naturally in the 100 GeV range,
but not too heavy: $m_t<$ 150 GeV. Inspired by the mass matrices obtained in
the model for quarks, we suggest an ansatz also including charged leptons. The
differences between $u$-, $d$- and $e$-type fermions are simply parametrized by
three complex coefficients $\eps{u}$, $\eps{d}$ and $\eps{e}$. Additional
consistent predictions are obtained: $m_s$=100-150 MeV and $m_u/m_d<$ 0.75.


title: Heavy Quarks and Leptons at $e^+e^-$ Colliders

abstract:
  The production of massive quarks and leptons in $e^+e^-$ collisions is
studied using exact helicity amplitudes. Total cross sections as a function of
$y_{\rm cut}$, in both the JADE and the $k_T$ algorithms, are presented and
compared with massless results. Some invariant mass distributions are examined
in relation to Higgs detection. Compact expressions for the helicity amplitudes
are given.


title: Neutrino Mixing

abstract:
  In the first part of these lectures the neutrino mixing hypothesis will be
considered in detail. We will discuss the possible schemes of neutrino mixing
and present the data of the recent experiments searching for effects due to
nonvanishing neutrino masses and mixing angles.In the second part of these
lectures the physics of solar neutrinos will be considered.We will discuss the
MSW resonance solution of the equation of evolution of a neutrino in matter and
present data of solar neutrino experiments.


title: On the nature of the electroweak phase transition

abstract:
  We discuss the finite-temperature effective potential of the Standard Model,
$\veff$, with emphasis on the resummation of the most important infrared
contributions. We compute the one-loop scalar and vector boson self-energies in
the zero-momentum limit. By solving the corresponding set of gap equations,
with the inclusion of subleading contributions, we find a non-vanishing
magnetic mass for the $SU(2)$ gauge bosons. We comment on its possible
implications for the nature of the electroweak phase transition. We also
discuss the range of validity of our approximations and compare this with other
approaches.


title: Radiative $W$ and $Z$ Decays and Spontaneous R-Parity Violation

abstract:
  We point out that in a class of supersymmetric models where R-parity
violation is induced by the spontaneous breaking of local $B-L$ symmetry, the
R-parity violating $W$ decay $W\rightarrow\slep\gamma$ and $Z$ decay
$Z\rightarrow\snu\gamma$, forbidden in the minimal supersymmetric standard
model (MSSM), occur at an enhanced rate compared to other models with R-parity
breaking. We find that the branching fractions for these modes can be of order
$10^{-5}$ .


title:
Relativistic Constituent Quark Model of Electroweak Properties of
  Baryons

abstract:
  We calculate the electroweak properties of nucleons and hyperons in a
relativistic constituent quark model using the light-front formalism. The
parameters of the model, namely the constituent quark mass and the confinement
scale, can be uniquely chosen for both the electromagnetic and weak
experimental data. A consistent physical picture of the $qqq$ system appears in
this work with a symmetric nucleon wave function and an asymmetric hyperon wave
function. Only for the strangeness-changing weak decays do we need nontrivial
form factors of the constituent quark.


title: Spin in Perturbative QCD; Coherent Hard Diffraction

abstract:
  I briefly review: (a) some recent developments in the theory of hard
scattering in QCD with polarized beams, and (b) coherent hard diffraction (that
is, hard scattering in diffractive events, with the Pomeron behaving in an
apparently point-like fashion).


title: 2 \to n threshold production at tree level

abstract:
  The threshold behavior of a theory with two coupled scalar fields $\chi$ and
$\phi$ is investigated. We compute the amplitude for two on-mass-shell
$\chi$-particles to produce an arbitrary number of $\phi$-particles at rest in
the tree approximation.


title: CP violating asymmetries in charged D meson decays

abstract:
  The CP violating asymmetries for Cabibbo suppressed charged D meson decays in
the standard model are estimated in the factorized approximation, using the
two-loop effective hamiltonian and a model for final state interactions
previously tested for Cabibbo allowed D decays. No new parameters are added.
The predictions are larger than expected and not too far from the experimental
possibilities.


title: 2-loop Integrals in the Standard Model

abstract:
  We introduce in typical examples new methods for the calculation of massive
loop integrals appearing in the radiative correction calculations of the
Standard Model.


title: Bose-Einstein Correlations for Mixed Neutral Mesons

abstract:
  Correlations are shown to arise in nonidentical mixed-particle pairs like
$K^o \bar K^o$ when observed in identical decay modes like $K_S K_S$ in
multiparticle final states containing many partial waves. No enhancement is
found in any single partial wave and all partial wave analyses of the s-wave
threshold resonance $a_o$ and $f_o$ should give the same results for all decay
modes. In CP violation experiments where $B^o - \bar B^o$ pairs are inclusively
produced and correlated decays into $\psi K_S$ and leptonic modes are observed,
the CP-violating lepton asymmetry is enhanced by a factor of two in the
kinematic region where Bose enhancement occurs.


title:
Shedding light on quarkonium formation by producing a photon in
  association

abstract:
  The process AB --> Quarkonium + photon + X, for a heavy quarkonium state such
as J/psi or Upsilon, is considered. The ratio of the cross-sections for this
process in pp and pp(bar) collisions is shown to be a vary sensitive probe of
models of quarkonium formation.


title:
Small Momentum Evolution of the Extended Drell--Hearn--Gerasimov Sum
  Rule

abstract:
  We investigate the momentum dependence of the extended Drell-Hearn-Gerasimov
sum rule. An economical formalism is developed which allows to express the
extended DHG sum rule in terms of a single virtual Compton amplitude in forward
direction. Rigorous results for the small momentum evolution are derived from
chiral perturbation theory within the one-loop approximation. Furthermore, we
evaluate some higher order contributions arising from $\Delta(1232)$
intermediate states and relativistic corrections. (2 figures available upon
request).


title: How unique are the MSW parameters ?

abstract:
  We investigate the effect of a possible large frozen-in magnetic field in the
core of the sun and a neutrino magnetic moment of the order of $10^{-10}$ Bohr
magneton on the MSW parameters. Such a possibility can completely depolarize
the $\nu_{eL}$ resulting in a factor of half of the emitted number. This in
combination with MSW can explain the present experimental data on solar
neutrinos but with a different region of the parameter space than the regular
MSW alone. In this scenario there is a larger region of parameter space
allowed. There is a large strip of parameter space corresponding to adiabatic
solution and no solution for large mixing angle region. The non-adiabatic
region still remains as a solution but shifted and larger relative to the
regular MSW.


title: Differentiating various extra $Z^{\prime}$'s at Future Colliders

abstract:
  We propose a way to differentiate between various extra $U(1)$ models using
flavor tagging in the decay modes $Z^{\prime}\rightarrow q{\bar{q}}$ once the
extra $Z^{\prime}$ is observed at future colliders in the lepton channel. A
generalization of the R parameter, namely, one for charge $\frac{1}{3}$ and one
for charge $\frac{2}{3}$ quark gives a two parameter test for the various
models. Flavor tagging eliminates the uncertainty because of extra fermions and
can reduce the QCD background at SSC/LHC dramatically. For $E_{6}$ and $SO(10)$
based models the former is always 3. This seems to be a very good way to
eliminate certain models.


title: Constraints on the Charged Higgs Sector from B Physics

abstract:
  We present the bounds that can be obtained on the charged Higgs sector in
two-Higgs-Doublet Models from measurements at LEP of the decay $B\to D\tau\nu$,
and from searches by CLEO for the inclusive decay $b\to s\gamma$.


title: Signals for Virtual Leptoquark Exchange at Colliders

abstract:
  We study the effects of virtual leptoquark exchange on charged current and
neutral current processes at HERA, on di-lepton production at the Tevatron, and
on quark pair production at LEP II. We present the areas of parameter space
that can be excluded at these colliders by searching for deviations from
Standard Model expectations.


title:
Summary Talk: International Symposium on Neutrino Astrophysics,
  Takayama/Kamioka (10/'92)

abstract:
  Contents:
  1. The Conference
  2. Solar Neutrinos
  -A. Operating Experiments
  -B. New Funded Experiments
  -C. Are Solar Neutrino Fluxes Time Dependent?
  -D. Have $pp$ Neutrinos Been Detected?
  -E. Is Directionality Required for Astronomical Observations?
  -F. Is There a Solar Neutrino Problem?
  -G. What Have We Learned?
  3. Supernova Neutrinos
  4. Atmospheric Neutrinos
  5. High-Energy Neutrinos
  6. Our Field Is Flourishing


title: Intermittency and Phase Transition

abstract:
  On the basis of a lattice gas model and the convolution formula with cell
construction scheme, we demonstrate that intermittency in the rapidity-space
with respect to the scaled moments comes from a phase transition between
ordered phase and disordered phase. It is pointed out that as concerns the
power-law behavior of the moments the critical exponent depends on the size of
rapidity interval in the case of the system which is not enough near to the
critical point.


title: Photon Propagation in Dense Media

abstract:
  Using thermal field theory, we derive simple analytic expressions for the
spectral density of photons in degenerate QED plasmas, without assuming the
usual non or ultra-relativistic limit. We recover the standard results in both
cases. Although very similar in ultra-relativistic plasmas, transverse and
longitudinal excitations behave very differently as the electron Fermi momentum
decreases.


title: Flow Equations for the Higgs Top System

abstract:
  The flow equations or exact RG equations for the Higgs Top System are solved
to leading order in $1/N_c$. This allows to relate arbitrary bare actions with
this field content continuously to effective low energy theories, and we find
the flow converging towards general renormalizable models. The assumption of a
bare action of the generalized Nambu-Jona-Lasinio type does not restrict the
parameters of the low energy theory.


title:
The Subleading Isgur-Wise Form Factor $\chi_3(v\cdot v')$ to Order
  $\alpha_s$ in QCD Sum Rules

abstract:
  We calculate the contributions arising at order $\alpha_s$ in the QCD sum
rule for the spin-symmetry violating universal function $\chi_3(v\cdot v')$,
which appears at order $1/m_Q$ in the heavy quark expansion of meson form
factors. In particular, we derive the two-loop perturbative contribution to the
sum rule. Over the kinematic range accessible in $B\to D^{(*)}\ell\,\nu$
decays, we find that $\chi_3(v\cdot v')$ does not exceed the level of $\sim
1\%$, indicating that power corrections induced by the chromo-magnetic operator
in the heavy quark expansion are small.


title: Predictive Ansatz for Fermion Masses in SUSY GUTS

abstract:
  We reexamine a succesful fermion mass Ansatz proposed by Giudice for a wide
range of the ratio $tan\beta =\frac {<\bar h>}{<h>}$ (where ${\bar h},h$ are
the two standard higgs fields), in the context of supersymmetric grand unified
theories. We find that the 7 predictions of the ansatz, $V_{us}, V_{cb},
V_{ub}, m_u, m_d, m_s$ and $m_b$ are in good agreement with the experiment when
either {\it i) } $tan\beta \simeq 1$ or {\it ii)} $tan\beta \geq 30$. A correct
prediction for the bottom mass gives a lower limit on $m_t\geq 125$ for case
{\it (i)}, in agreement with the previous analysis, while in case {\it (ii)}
$m_t\geq 145$.


title:
Unitary Gauge, Stueckelberg Formalism and Gauge Invariant Models for
  Effective Lagrangians

abstract:
  Within the framework of the path-integral formalism we reinvestigate the
different methods of removing the unphysical degrees of freedom from
spontanously broken gauge theories. These are: construction of the unitary
gauge by gauge fixing; \rx -limiting procedure; decoupling of the unphysical
fields by point transformations. In the unitary gauge there exists an extra
quartic divergent Higgs self-interaction term, which cannot be neglected if
perturbative calculations are performed in this gauge. Using the St\"uckelberg
formalism this procedure can be reversed, i.~e., a gauge theory can be
reconstructed from its unitary gauge. We also discuss the equivalence of
effective-Lagrangian theories, containing arbitrary interactions, to
(nonlinearly realized) spontanously broken gauge theories and we show how they
can be extended to Higgs models.


title: Comment on ``Chiral Dilepton Model and the Flavor Question''

abstract:
  We comment a model based on the $SU(3)_c \otimes SU(3)_L \otimes U(1)_X$
gauge symmetry recently proposed by Frampton. We stressed that the analysis of
flavor changing neutral currents impose strong constraints on th emasses of the
new gauge bosons of the model.


title: Jet inclusive cross sections

abstract:
  Minijet production in jet inclusive cross sections at hadron colliders, with
large rapidity intervals between the tagged jets, is evaluated by using the
  BFKL pomeron. We describe the jet inclusive cross section for an arbitrary
number of tagged jets, and show that it behaves like a system of coupled
pomerons.


title:
Neutral Currents and GIM Mechanism in SU(3)_L X U(1)_N Models for
  Electroweak Interactions

abstract:
  We study the Glashow-Iliopoulos-Maiani mechanism for
flavor-changing-neutral-currents suppression in both, the gauge and Higgs
sectors, for models with $SU(3)_L\otimes U(1)_N$ gauge symmetry. The models
differ one from the other only with respect to the representation content. The
main features of these models are that in order to cancel the triangle
anomalies the number of families must be divisible by three (the number of
colors) and that the lepton number is violated by some lepton-gauge bosons and
lepton-scalar interactions.


title: What can the L3 $\gamma\gamma ll$ events be?

abstract:
  We consider the 4 $\gamma\gamma ll$ ($l=\mu,\ e$) events reported by the L3
collaboration, and go through the logical possibilities which could explain the
events. If they are not coincidental bremsstrahlung events, we find that the
physics which they could point to is extremely limited. One possibility would
be to have a new 60 GeV scalar (or pseudoscalar) particle $X^0$ with an
off-diagonal coupling to a $Z$ and $Z'$ which is non-perturbative ($\alpha >
1$), where the $Z'$ couplings to $\nu\bar\nu$ are suppressed. One could also
construct a model involving $X^0$, and a second scalar $X'^0$ with a large
$X'll$ coupling. We do not promote either of these models, but hope they would
prove to be useful guidelines, should the L3 events turn out to be new physics.


title:
CP-Violating Yukawa Couplings in the Skyrme Model and the Neutron
  Electric Dipole Moment

abstract:
  We argue that the large-$\Nc$ behaviour of the Yukawa couplings in the Skyrme
model involves issues more subtle than the vanishing of linear fluctuations
needed for classical stability of the skyrmion. The chiral fluctuations about
the skyrmion must be quantized in order to reach a conclusion. An improved
quantization procedure allows us to confront this question directly.
  The pion-nucleon coupling constants $\gcup$ (CP conserving) and $\bgcup$ (CP
violating) are calculated in the large-$\Nc$, three-flavour Skyrme model by
direct evaluation of the leading matrix elements appearing in the LSZ reduction
formula. We find that $\gcup \sim \Nc^{{3 \over 2}}$, but that, at most,
$\bgcup \sim m^2_\pi \Nc^{-\shalf}$. These results show that the leading
contribution to the neutron electric dipole moment in large-$\Nc$ Skyrme model
is the direct one ($\Dn \sim \Nc m^2_\pi$), rather than the pion loop
contribution.


title: Chiral Estimates of Strong CP Violation Revisited

abstract:
  The effects of the CP violating $\theta$ term in the QCD Lagrangian upon low
energy hadronic phenomenology are reconsidered. Strong CP violating
interactions among Goldstone bosons and octet baryons are incorporated into an
effective chiral Lagrangian framework. The $\theta$ term's impact upon the
decays $\eta\to\pi\pi$ and $\pi^0\to\gamma\gamma$ is then investigated but
found to be extremely small. A refined model independent estimate of
nonanalytic contributions to the neutron electric dipole moment is also
determined using velocity dependent Baryon Chiral Perturbation Theory. We
obtain the approximate upper bound $|\theta| < 4.5 \times 10^{-10}$.


title: Light fermions in composite models

abstract:
  In preon models based on chiral gauge theories, we show that light composite
fermions can ensue as a result of gauging a subset of preons in a vector-like
manner. After demonstrating how this mechanism works in a toy example, we
construct a one generation model of quarks which admits a hierarchy between the
up and down quark masses as well as between these masses and the compositeness
scale. In simple extensions of this model to more generations we discuss the
challenges of obtaining any quark mixing. Some possible phenomenological
implications of scenarios where quarks and leptons which are heavier are also
less pointlike are also considered.


title:
Discontinuity Theorem for First Order Phase Transitions. Implications
  for QCD

abstract:
  A first order phase transition leading to deconfinement and chiral
restoration is a likely possibility for QCD, at least in some region of the
temperature-density plane. A signal for a unique transition is that the order
parameters for such transitions (which can be understood in terms of symmetries
only in limiting situations of very massive or massless quarks) are both
discontinuous at the same critical temperature. We show that such a situation
can be understood on a precise thermodynamical basis because of a general
relation among discontinuities which holds for first order transitions. We
derive the result by a generalization of the Clausius-Clapeyron equation and
also through the effective action formalism. We illustrate the theorem in an
elementary example.


title: Hyperfine Effects and Large $1/{m}_{Q}^{2}$ Corrections

abstract:
  Effects associated with hyperfine mass splitting between pseudo\-scalar and
vector mesons may induce surprisingly large $1/{m}_{Q}^{2}$ corrections in the
heavy quark expansion. We demonstrate this in a relativistic quark model by
calculating to all orders in $1/{m}_{Q}$, with and without hyperfine effects,
and comparing to the first order results. Total corrections of 30\% or more are
quite possible in the decay rates for $B\rightarrow Dl\nu$ and $B\rightarrow
D^{\ast}l\nu$ near zero recoil.


title: Mass Matrix Models

abstract:
  It is possible that the hierarchy in the masses and mixing of quarks is a
result of a horizontal symmetry. The smallness of various parameters is related
to their suppression by high powers of a scale of new physics. We analyze in
detail the structure of such symmetries in view of new experimental data and
present explicit models consistent with all phenomenological constraints. We
show that it is possible that the flavor dynamics can be at accessible energies
-- as low as a $TeV$.


title:
On the Production of Flux Vortices and Magnetic Monopoles in Phase
  Transitions

abstract:
  We examine the basic assumptions underlying a scenario due to Kibble that is
widely used to estimate the production of topological defects. We argue that
one of the crucial assumptions, namely the geodesic rule, although completely
valid for global defects, becomes ill defined for the case of gauged defects.
We address the issues involved in formulating a suitable geodesic rule for this
case and argue that the dynamics plays an important role in the production of
gauge defects.


title: On amplitude zeros at threshold

abstract:
  The occurrence of zeros of 2 to n amplitudes at threshold in scalar theories
is studied. We find a differential equation for the scalar potential, which
incorporates all known cases where the 2 to n amplitudes at threshold vanish
for all sufficiently large $n$, in all space-time dimensions, $d\ge 1$. This
equation is related to the reflectionless potentials of Quantum Mechanics and
to integrable theories in 1+1 dimensions. As an application, we find that the
sine-Gordon potential and its hyperbolic version, the sinh-Gordon potential,
also have amplitude zeros at threshold, ${\cal A}(2\to n)=0$, for $n\ge 4$ and
$d\ge 2$, independently of the mass and the coupling constant.


title: Beyond the Standard Model in Tau Decays

abstract:
  INVITED TALK AT SECOND WORKSHOP ON TAU LEPTON PHYSICS, COLOMBUS, OHIO,
SEPTEMBER 1992


title:
Constraints on singlet right-handed neutrinos coming from the
  $Z^0$-width

abstract:
  We study the constraints on masses and mixing angles imposed by the measured
$Z^0$ invisible width, in a model in which a singlet right-handed neutrino
mixes with all the Standard Model neutrinos.