title: Past, Present, and Possible Future Limits on the Photon Rest Mass

abstract:
  In an historical context, present limits on the photon rest mass are
reviewed. More stringent, yet speculative, limits which have been proposed are
mentioned. Finally, new theoretical ideas and possible experimental
improvements on the present limits are discussed, along with possible
relationships between these two areas.


title: The electroweak theory of SU(3) $\times$ U(1)

abstract:
  An electroweak model of SU(3) $\times$ U(1) gauge group is studied. {}From
the group theoretical constraint, the symmetry breaking of this model to the
standard model occurs at 1.7~TeV or lower. Hence the mass of the new neutral
gauge boson is less than 1.7 TeV. The $Y^\pm$ and $Y^{\pm\pm}$ masses are found
to be less than half of the $Z_2$ mass. Thus, the decays $Z_2 \to Y^{++}
Y^{--}$ with $Y^{++} \to 2\ell^+ \: (\ell \!=\! e,\mu,\tau)$ is allowed,
providing spectacular signatures at future colliders. {}From the
flavor-changing neutral current processes, the representations of quarks can be
uniquely determined. The neutrino-isoscalar scattering experiments are also
considered.


title:
Incorporation of QCD Effects in Basic Corrections of the Electroweak
  Theory

abstract:
  We study the incorporation of QCD effects in the basic electroweak
corrections \drcar, \drcarw, and \dr. They include perturbative
\Ord{\alpha\alpha_s} contributions and $t\bar{t}$ threshold effects. The latter
are studied in the resonance and Green-function approaches, in the framework of
dispersion relations that automatically satisfy relevant Ward identities.
Refinements in the treatment of the electroweak corrections, in both the \ms\
and the on-shell schemes of renormalization, are introduced, including the
decoupling of the top quark in certain amplitudes, its effect on
$\hat{e}^2(\mz)$ and \sincarmz, the incorporation of recent results on the
leading irreducible \Ord{\alpha^2} corrections, and simple expressions for the
residual, i.e.\ ``non-electromagnetic'', parts of \drcar, \drcarw, and \dr. The
results are used to obtain accurate values for \mw\ and \sincarmz, as functions
of \mt\ and \mh. The higher-order effects induce shifts in these parameters
comparable to the expected experimental accuracy, and they increase the
prediction for \mt\ derived from current measurements. The \ms\ and the
on-shell calculations of \dr, in a recently proposed formulation, are compared
and found to be in excellent agreement over the wide ranges $60\GeV \leq \mh
\leq 1 \TeV$, $\mz \leq \mt \leq 250 \GeV$.


title: Electroweak Z-string in Two-Higgs-Doublet Standard Model

abstract:
  We derive electroweak Z-string solutions in the Glashow-Weinberg-Salam model
with two Higgs doublets. The existence of such solutions in particular requires
a specific relation between the ratio of the two Higgs vacuum expectation
values, {\it i.e.} $\tan\beta$, and the couplings in the Higgs potential.


title: QCD at Finite Temperature: A Variational Approach:

abstract:
  We develop here a nonperturbative framework to study quantum chromodynamics
(QCD) at finite temperatures using the thermofield dynamics (TFD) method of
Umezawa. The methodology considered here is self-consistent and variational.
There is a dynamical generation of a magnetic gluon mass. This eliminates the
infrared problems associated with perturbative QCD calculations at finite
temperatures. We obtain here the thermodynamical quantities like free energy
density, pressure and entropy density. We also calculate the temperature
dependence of SVZ parameter ${\alpha_{s} \over \pi}<{G^a}_{\mu \nu } {G^{a \mu
\nu }}>$. The condensate vanishes at the critical temperature in accordance
with recent hot sum rule calculations. The present method gives an insight to
the vacuum structure in QCD at zero temperature as well as at finite
temperatures in a co-ordinated manner. (to appear in Z. Physik C )


title:
Some Two-Loop Corrections to the Finite Temperature Effective Potential
  in the Electroweak Theory

abstract:
  Perturbation theory at finite temperature suffers from well-known infrared
problems. In the standard model, as a result, one cannot calculate the
effective potential for arbitrarily small values of $\phi$, the Higgs
expectation value. Because the Higgs field is now known not to be extremely
light, it is necessary to determine whether perturbation theory is a reliable
guide to properties of the weak phase transition. In this note, we evaluate the
most singular contributions to the potential at two loops as well as the
leading strong interaction contributions. Above the critical temperature, the
strong interaction corrections are reasonably small, while the weak corrections
are about 10\%, even for rather small values of the Higgs field. At the
critical temperature, the weak corrections have a more substantial effect,
rendering the transition significantly more first order, but not significantly
changing the upper bound on the Higgs mass required for baryogenesis.


title: QCD Mass Inequalities in the Heavy Quark Limit

abstract:
  QCD inequalities are derived for the masses of mesons and baryons containing
a single heavy quark using the heavy quark effective field theory. A rigorous
lower bound is obtained for the $\bar\Lambda$ parameters of the heavy quark
effective theory that parameterize $1/m$ corrections, $\bar\Lambda$ > 237 MeV
for mesons, and $\bar \Lambda > 657$ MeV for baryons. The inequalities on
$\bar\Lambda$ imply the inequalities $m_c < 1627$ MeV and $m_b < 5068$ MeV for
the mass parameters of the heavy quark effective field theory.


title:
On-Mass-Shell Renormalization of the $\langle \bar{t}t \rangle$
  Contribution to the $\Delta I = 1/2$ $s \leftrightarrow d$ Self-Energy
  Transition

abstract:
  In $\langle \bar{t}t \rangle$-scenarios for dynamical electroweak symmetry
breaking, the presence of a very large t-quark condensate necessarily generates
an $s \leftrightarrow d$ self-energy transition which will contribute
exclusively to $\Delta I = 1/2$ strangeness-changing matrix elements. This
contribution is calculated and compared to the purely perturbative
contribution, which is well-known to be far too small to have an appreciable
effect on $\Delta I = 1/2$ strangeness-changing matrix elements after
mass-shell renormalization subtractions are taken into account. The ratio
between the t-quark condensate's contribution and the standard-model
perturbative contribution to the mass-shell renormalized $s \leftrightarrow d$
self-energy transition is shown to be of order $\mid m_t \langle \bar{t} t
\rangle \mid / M_W ^4$, suggesting that the large t-quark condensate proposed
for electroweak symmetry breaking may also be responsible for the $\Delta


title:
Bounds on Bess Model Parameters from Vector-Boson Production in e+e-
  Collisions

abstract:
  The BESS model is the Higgs-less alternative to the standard model of
electroweak interaction, based on nonlinearly realized spontaneous symmetry
breaking. Since it is nonrenormalizable, new couplings (not existing in the SM)
are induced at each loop order. On the basis of the one loop induced
vector-boson self-couplings we study the two- and three-vector-boson-production
processes in $e^+e^-$ collisions at $\sqrt{s}=500 GeV$, the expected energy of
the next $ e^+e^-$ linear collider (NLC). Assuming that NLC results will agree
with the SM predictions within given accuracy we identify the bounds for the
free parameters of the BESS model.


title: On the Analytic Structure of Hadronic Amplitudes in QCD

abstract:
  Analytic properties of hadronic amplitudes are discussed within the framework
of QCD as formulated on the basis of the BRST algebra. Local, composite fields
are introduced for hadrons. Given confinement, it is shown that hadronic
amplitudes have no thresholds or structure singularities (anomalous thresholds)
which are directly related to the underlying quark-gluon structure. In
contrast, general amplitudes of QCD must have singularities in channels with
non-zero color quantum number, which can be related to unphysical states.


title: Phase Transitions in Quantum Field Theory

abstract:
  We discuss here phase transitions in quantum field theory in the context of
vacuum realignment through an explicit construction. Vacuum destabilisation may
occur through a scalar attaining a nonzero expectation value, or through a
condensate mechanism as in superconductivity and for chiral symmetry breaking,
or by some other mechanism not taken here. Phase transition is defined as
vacuum realignment with a discontinuity in some observables which correspond to
the classical order parameters. The method is nonperturbative and variational,
using equal time algebra and an ansatz for the construction of the physical
vacuum.


title:
Very Large Intermediate Breaking Scale In The Gepner Three Generation
  Model

abstract:
  A detailed study of the intermediate symmetry breaking scale, via the
renormalization group equations, for a three generation heterotic string model
arising from the N=2 superconformal construction is reported. The numerical
study shows that the model admits a very large intermediate breaking scale
$\op{>}{\sim}1.0\times10^{16}$ GeV. The role of the gauge singlets in this
model is studied, and it is found that these fields play a crucial role in
determining the directions and the scale of the intermediate symmetry breaking.
The importance of the mixing in generation space is also studied. The
generation mixing terms are found to have special effects in the intermediate
symmetry breaking. Remarkably these terms can produce some {\it new} Yukawa
couplings (not present at the Planck scale) through loops. These couplings are
in general very small compared to the ones with non-vanishing tree level values
and thus offer a {\it new} mechanism to solve the lepton/quark mass hierarchy
problem.


title:
Heavy Meson Masses in Chiral Perturbation Theory with Heavy Quark
  Symmetry

abstract:
  The $SU(3)$ and hyperfine mass splittings of mesons containing a single heavy
quark are computed to one-loop order in chiral perturbation theory with heavy
quark spin symmetry. Electromagnetic contributions of order $\alpha_em$ are
included. The observed values of the mass splittings are consistent with the
one-loop chiral perturbation theory calculation. The $d-u$ hyperfine splitting
$(D^{* +} - D^+) - (D^{*0} - D^0)$ is equal to $(m_d - m_u)/ m_s$ times the
$s-d$ hyperfine splitting $(D_s^{* +} - D_s^+) - (D^{*+} - D^+)$ upto
electromagnetic contributions. The small observed value of the $s-d$ hyperfine
splitting implies that the $d-u$ hyperfine splitting is completely dominated by
electromagnetic mass contributions.


title: Multiloop String-Like Formulas for QED

abstract:
  Multiloop gauge-theory amplitudes written in the Feynman-parameter
representation are poised to take advantage of two important developments of
the last decade: the spinor-helicity technique and the superstring
reorganization. The former has been considered in a previous article; the
latter will be elaborated in this paper. We show here how to write multiloop
string-like formulas in the Feynman-parameter representation for any process in
QED, including those involving other non-electromagnetic interactions. The
general connection between the Feynman-parameter approach and the
superstring/first-quantized approach is discussed. In the special case of a
one-loop multi-photon amplitude, these formulas reduce to the ones obtained by
the superstring and the first quantized methods. The string-like formulas
exhibits a simple gauge structure which makes the Ward-Takahashi identity
apparent, and enables the integration-by-parts technique of Bern and Kosower to
be applied, so that gauge-invariant parts can be extracted diagram-by-diagram
with the seagull vertex neglected.


title: Jets and Jet Multiplicities in High Energy Photon-Nucleon Inetraction:

abstract:
  We discuss the theory of jet events in high-energy photon-proton interactions
using a model which gives a good description of the data available on total
inelastic $\gamma p$ cross sections up to $\sqrt{s}$=210 GeV. We show how to
calculate the jet cross sections and jet multiplicities and give predictions
for these quantities for energies appropriate for experiments at the HERA $ep$
collider and for very high energy cosmic ray observations.


title: High Energy Photon-Nucleon and Photon-Nucleus Cross Sections

abstract:
  We re\,examine the theory of hadronic photon-nucleon interactions at the
quark-gluon level. The possibility of multiple parton collisions in a single
photon-nucleon collision requires an eikonal treatment of the high-energy
scattering process. We give a general formulation of the theory in which the
$\gamma p$ cross section is expressed as a sum over properly eikonalized cross
sections for the interaction of the virtual hadronic components of the photon
with the proton, with each cross section weighted by the probability with which
that component appears in the photon, and then develop a detailed model which
includes contributions from light vector mesons and from excited virtual states
described in a quark-gluon basis. The parton distribution functions which
appear can be related approximately to those in the pion, while a weighted sum
gives the distribution functions for the photon. We use the model to make
improved QCD-based predictions for the total inelastic photon-nucleon and
photon-nucleus cross sections at energies relevant for HERA experiments and
cosmic ray observations. We emphasize the importance in this procedure of
including a soft-scattering background such that the calculated cross sections
join smoothly with low-energy data.


title: Spontaneous Baryogenesis in Supersymmetric Models

abstract:
  In this paper we extend the results of previous work on spontaneous
baryogenesis to general models involving CP violation in the Higgs sector. We
show how to deal with Chern-Simons terms appearing in the effective potential
arising from phase changes in the vacuum expectation values of the Higgs
fields. In particular, this enables us to apply this mechanism to general
supersymmetric models including the minimal supersymmetric standard model, and
the extended model with a gauge singlet. A comparison is made between this
approach, and that in which one solves the equations of motion for Higgs
winding modes. As anticipated in earlier work, the effect of the latter
approach is found to be small.


title: The Third Electromagnetic Constant of an Isotropic Medium:

abstract:
  In addition to the dielectric and magnetic permeability constants, another
constant is generally needed to describe the electrodynamic properties of a
linear isotropic medium. We discuss why the need for the third constant arises
and what sort of physical situations can give rise to a non-zero value for it.
This additional constant, which we call the {\em ``Activity Constant''} and
denote by $\zeta$, can explain optical activity and other phenomena from a
purely macroscopic and phenomenological point of view.


title: Detailed Stability Analysis of Electroweak Strings

abstract:
  We give a detailed stability analysis of the Z-string in the standard
electroweak model. We identify the mode that determines the stability of the
string and numerically map the region of parameter space where the string is
stable. For $\sin^2 \theta_W = 0.23$, we find that the strings are unstable for
a Higgs mass larger than 23GeV. Given the latest constraints on the Higgs mass
from LEP, this shows that, if the standard electroweak model is realized in
Nature, the existing vortex solutions are unstable.


title:
Spectral Functions for Heavy-Light Currents and Form Factor Relations in
  Hqet

abstract:
  We derive relations among form factors describing the current-induced
transitions: (vacuum) $\rightarrow B,B^{*}, B \pi, B^{*} \pi, B \rho$ and
$B^{*} \rho$ using heavy quark symmetry. The results are compared to
corresponding form factor relations following from identities between scalar
and axial vector, and pseudoscalar and vector spectral functions in the heavy
quark limit.


title:
A Review of the Instability of Hot Electroweak Theory and its Bounds on
  $m_h$ and $m_t$

abstract:
  [Talk presented at the International Seminar Quarks `92, Zvenigorod, Russia,
May 11-17, 1992.] The electroweak vacuum need not be absolutely stable. For
certain top and Higgs masses in the Minimal Standard Model, it is instead
metastable with a lifetime exceeding the present age of the Universe. The decay
of our vacuum may be nucleated at low temperature by quantum tunneling or at
high temperature in the early Universe by thermal excitation. I briefly review
the constraints on top and Higgs masses from requiring that the electroweak
vacuum be sufficiently stable to have survived to the present day.


title: Linear Potentials and Galactic Rotation Curves

abstract:
  We derive a simple, closed form expression for the potential of a thin
exponential disk of stars interacting through gravitational potentials of the
form $V(r)=-\beta /r+\gamma r/2$, the potential associated with fundamental
sources in the fourth order conformal invariant theory of gravity which has
recently been advanced by Mannheim and Kazanas as a candidate alternative to
the standard second order Einstein theory. Using the model, we obtain a
reasonable fit (flat to within $\pm3\%$) to the (prototypical) NGC3198 $HI$
rotation curve data without the need for any non-luminous or dark matter. Our
study suggests that th observed flatness of rotation curves may only be an
intermediate phenomenon, and an asymptotic one.


title:
Upper Bounds on the Lightest Higgs Boson Mass in General Supersymmetric
  Standard Models

abstract:
  In a general supersymmetric standard model there is an upper bound $m_h$ on
the tree level mass of the $CP=+1$ lightest Higgs boson which depends on the
electroweak scale, $\tan \beta$ and the gauge and Yukawa couplings of the
theory. When radiative corrections are included, the allowed region in the
$(m_h,m_t)$ plane depends on the scale $\Lambda$, below which the theory
remains perturbative, and the supersymmetry breaking scale $\Lambda_s$, that we
fix to $1\ TeV$. In the minimal model with $\Lambda=10^{16}\ GeV$: $m_h<130\
GeV$ and $m_t<185\ GeV$. In non-minimal models with an arbitrary number of
gauge singlets and $\Lambda=10^{16}\ GeV$: $m_h<145\ GeV$ and $m_t<185\ GeV$.
We also consider supersymmetric standard models with arbitrary Higgs sectors.
For models whose couplings saturate the scale $\Lambda=10^{16}\ GeV$ we find
$m_h<155\ GeV$ and $m_t<190\ GeV$. As one pushes the saturation scale $\Lambda$
down to $\Lambda_s$, the bounds on $m_h$ and $m_t$ increase. For instance, in
models with $\Lambda=10\ TeV$, the upper bounds for $m_h$ and $m_t$ go to $415\
GeV$ and $385\ GeV$, respectively.


title: A Z' Model Which May Be Relevant to the New LEP Events

abstract:
  A multi-Higgs model with an extra neutral gauge boson ($Z'$) is introduced.
One scalar Higgs boson ($H_2$) in this model decays dominantly into a photon
pair. The $Z'$ decay to $\mu^+\mu^-$ gets a much larger branching ratio than
the $Z$ decay to this channel. The $Z Z' H_2$ vertex provides a final state
from $Z$ decay resembling the new $l^+l^-\gamma\gamma$ events at the LEP. Other
promising phenomenology, such as $Z \rightarrow l\bar l Z'$ is also discussed.


title: The Equivalence Theorem and Global Anomalies

abstract:
  In the presence of some forms of global anomalies, the equivalence theorem,
which relates the interactions of longitudinal gauge bosons to those of the
Goldstone bosons, is not always valid. This can occur when the Goldstone sector
contains an anomaly which is canceled in the gauge currents by the effects of a
different sector of the theory. The example of the Standard Model without Higgs
particles is used to illustrate this phenomena.


title: Dimensionally Regulated One-Loop Integrals

abstract:
  We describe methods for evaluating one-loop integrals in $4-2\e$ dimensions.
We give a recursion relation that expresses the scalar $n$-point integral as a
cyclicly symmetric combination of $(n-1)$-point integrals. The computation of
such integrals thus reduces to the calculation of box diagrams ($n=4$). The
tensor integrals required in gauge theory may be obtained by differentiating
the scalar integral with respect to certain combinations of the kinematic
variables. Such relations also lead to differential equations for scalar
integrals. For box integrals with massless internal lines these differential
equations are easy to solve.


title:
An Example of Semiclassical Instanton-Like Scattering: (1+1) Dimensional
  Sigma Model

abstract:
  A solution to the classical field equations in the massless (1+1)-dimensional
O(3) sigma model is found, which describes a multi-particle instanton-like
transition at high energy. In the limit of small number of initial particles,
the number of final particles is shown to be also small, and the probability of
the transition is suppressed by $\exp(-2S_0)$, where $S_0$ is the instanton
action. This solution, however, does not correspond to the maximum transition
probability among all states with given number of incoming particles and
energy. Unless the limit $g^2 n_{initial}\to0$ is exponentially sensitive to
the structure of the initial state, our results imply that well above the
sphaleron energy, the instanton-induced cross section becomes again suppressed
by the instanton exponent, and the number of final paricles is again small.


title: Gluon Condensates, Chiral Symmetry Breaking and Pion Wave Function

abstract:
  We consider here chiral symmetry breaking in quantum chromodynamics arising
from gluon condensates in vacuum. Through coherent states of gluons simulating
a mean field type of approximation, we show that the off-shell gluon
condensates of vacuum generate a mass-like contribution for the quarks, giving
rise to chiral symmetry breaking. We next note that spontaneous breaking of
global chiral symmetry links the four component quark field operator to the
pion wave function. This in turn yields many hadronic properties in the light
quark sector in agreement with experiments, leading to the conclusion that low
energy hadron properties are primarily driven by the vacuum structure of
quantum chromodynamics.


title: An Orbifold Compactification with Three Families from Twisted Sectors

abstract:
  We obtain a three generational $SU(3)_c\times SU(3)_w \times U(1)^4\times
[SO(12)\times U(1)^2]^\prime$ model from an orbifold construction with the
requirement that three generations arise from twisted sectors. There exist
supersymmetric vacua realizing the standard model. In one example the anomalous
$U(1)$ breaks the gauge symmetry down to $SU(3)_c\times SU(2)_w\times
U(1)_Y\times SO(12)^\prime$.


title:
Measuring the Beam Polarizations and the Luminosity at Photon-Photon
  Colliders

abstract:
  We present methods to measure the beam polarizations and the luminosity of
$\gamma \gamma$ colliders at TeV energy scale.
  The beam polarizations of a $\gamma \gamma$ collider can easily be monitored
by comparing the numbers of events of the processes $\gamma \gamma$
$\rightarrow$ $\ell^+ \ell^-$ and $\gamma \gamma$ $\rightarrow$ $W^+ W^-$,
where $\ell$ means $e$ or $\mu$.
  The luminosity of a $\gamma \gamma$ collider is also measurable by the event
rate of $W$ boson pair productions and the light lepton pair productions.


title: Dynamical CP Violation in Composite Higgs Models

abstract:
  The dynamical origin of the CP violation in electroweak theory is
investigated in composite Higgs models. The mechanism of the spontaneous CP
violation proposed in other context by Dashen is adopted to construct simple
models of the dynamical CP violation.
  Within the models the size of the neutron electric dipole moment is estimated
and the constraint on the $\varepsilon$-parameter in K-meson decays is
discussed.


title: On the 545 keV Line in the Spectrum of the Crab Nebula

abstract:
  The GRANAT group (R. Sunyaev {\it et al.\/}, Central Bureau of Astronomical
Telegrams, International Astronomical Union, Circular No.~5481) recently
reported the observation of a $(545 \pm 11)$ keV line in the spectrum of the
Crab Nebula. It is tempting to associate this with the positron-electron
annihilation line at 511 keV. If this line originates from some transition at
the surface of the neutron star in the Crab, we expect a red shift of around
10\% rather then the observed blue shift of $\sim 35$ keV; in fact, this
gravitational red shift implies that the natural frequency of the observed line
is also 10\% higher, or around 600 keV. In this article we shall present a
mechanism for generating such a split from 511 keV. For this mechanism to be
successful we require: (a) surface magnetic fields, in the annihilation region,
to be $(3-8)\times 10^{12}$~G and to point in our direction, (b) surface
densities of $(10^5-10^6)$ g/cc. Both of these assumptions are consistent with
pulsar models.


title:
Chiral Perturbation Theory for $B \rightarrow D^*$ and $B \rightarrow D$
  Semileptonic Transition Matrix Elements at Zero Recoil

abstract:
  Heavy quark symmetry predicts the value of $B \rightarrow D$ and $B
\rightarrow D^*$ transition matrix elements of the current $\bar c \gamma_\mu
(1 - \gamma_5)b$, at zero recoil (where in the rest frame of the $B$ the $D$ or
$D^*$ is also at rest). We use chiral perturbation theory to compute the
leading corrections to these predictions which are generated at low momentum,
below the chiral symmetry breaking scale.


title: Paradoxes in Strange Quark Contributions to Hyperon Spins

abstract:
  Data for magnetic moments and semileptonic decays show disagreements between
experimental values and theoretical predictions not easily explained by simple
models for $\Lambda$ and $\Sigma$ hyperons.


title: A Signal for Technicolor?

abstract:
  We propose an interpretation for the ($l\bar l\gamma \gamma ,\ M_{\gamma
\gamma }=60{\rm GeV}$) events, which have recently been reported by L3 group at
LEP. This may be a first signal of `Technicolor' theory.


title:
Planck-Scale Physics and Solutions to the Strong CP Problem without
  Axion

abstract:
  We analyse the impact of quantum gravity on the possible solutions to the
strong CP problem which utilize the spontaneously broken discrete symmetries,
such as parity and time reversal invariance. We find that the stability of the
solution under Planck scale effects provides an upper limit on the scale
$\Lambda$ of relevant symmetry breaking. This result is model dependent and the
bound is most restrictive for the seesaw type models of fermion masses, with
$\Lambda < 10^6$ GeV.


title: Electroweak Strings: A Progress Report

abstract:
  I describe the string solutions in the standard electroweak model and argue
that they may be stabilized by quark, lepton or other bound states. I then
reinterpret the sphaleron in terms of electroweak strings and show that it can
be viewed as a loop of W-string or a segment of Z-string. (Talk presented at
Texas/Pascos 1992 at Berkeley.)


title:
On the Validity of Perturbative Evolution of Structure Functions from
  Low $Q^2$

abstract:
  The validity of using QCD perturbation theory to generate dynamically the
parton distribution functions of hadrons, starting from a valencelike input at
low $Q^2$, is discussed. In particular, we consider the prescription of Barone
{\em et al} who evolve from $Q^2 = 0$, and that of Gl\"uck {\em et al} who
start evolution from $Q^2 \simeq (2\Lambda_{QCD})^2$.


title: Measuring the Wess-Zumino Anomaly in Tau Decays

abstract:
  We propose to measure the Wess-Zumino anomaly contribution by considering
angular distributions in the decays $\tau\to\nu_\tau \eta\pi^{-}\pi^{0}$,
$\tau\to\nu_\tau K^- \pi^{-} K^+ $ and $\tau\to\nu_\tau K^- \pi^- \pi^+$.
Radial excitations of the $K^*$, which cannot be seen in $e^++e^-$, should be
observed in the $ K^- \pi^+ \pi^-$ decay channel.


title: QCD Corrections to Toponium Production at Hadron Colliders

abstract:
  Toponium production at future hadron colliders is investigated. Perturbative
QCD corrections to the production cross section for gluon fusion are calculated
as well as the contributions from gluon-quark and quark-antiquark collisions to
the total cross section. The dependence on the renormalization and
factorization scales and on the choice of the parton distribution functions is
explored. QCD corrections to the branching ratio of $\eta_{t}$ into
$\gamma\gamma$ are included and the two-loop QCD potential is used to predict
the wave function at the origin. The branching ratio of $\eta_{t}$ into $\gamma
Z$, $ZZ$, $HZ$ and $WW$ is compared with the $\gamma\gamma$ channel.


title: Errata for Higgs Bosons in Supersymmetric Models: I, II and III

abstract:
  Errata are given for J.F. Gunion and H.E. Haber, Nucl. Phys. B272 (1986) 1,
Nucl. Phys. B278 (1986) 449, and Nucl. Phys. B307 (1988) 445.


title:
Implications of $\tau$ Decays into Strange Scalar and Axial Vector
  Mesons

abstract:
  Recent reports of the observation of the decay $\tau \rarrow \nu_{\tau} + K +
\pi + \pi$ raise interesting questions. The $u-s$ quark mass difference can
induce an effective second-class current in the strange sector and enhance
decays to helicity-suppressed scalar states. This suggests searches for scalar
strange mesons in the $\tau \rarrow \nu_{\tau} + K + \eta' $ and $\tau \rarrow
\nu_{\tau} + K + \pi$ decay modes. $\tau$ decays to axial vector final states
may clarify strange meson spectroscopy by analogy with the clarification of the
$a_1$ problem in the nonstrange sector. Open questions include mixing effects
in the strange axial vector mesons and the implications of models based on QCD
for hadronization and final state interactions following the creation of a $q
\bar q$ pair by a weak vertex,


title: Color, from baryon spectroscopy to qcd

abstract:
  I review the discovery of the color degree of freedom in hadronic physics,
and the developments which led from that discovery to the local gauge theory of
color, quantum chromodynamics.


title: Spherical Quantum Chromodynamics of Heavy Quark Systems

abstract:
  We propose a model for Quantum Chromodynamics, obtained by ignoring the
angular dependence of the gluon fields, which could qualitatively describe
systems containing one heavy quark. This leads to a two dimensional gauge
theory which has chiral symmetry and heavy quark symmetry. We show that in a
light cone formalism, the Hamiltonian of this spherical QCD can be expressed
entirely in terms of color singlet variables. Furthermore, in the large $N_c$
limit, it tends to a classical hadron theory. We derive an integral equation
for the masses and wavefunctions of a heavy meson. This can be interpreted as a
relativistic potential model. The integral equation is scale invariant, but
renormalization of the coupling constant generates a scale. We compute the
approximate beta function of the coupling constant, which has an ultraviolet
stable fixed point at the origin.


title: The $\eta_6$ and Massive Photon Pairs at LEP

abstract:
  The $\eta_6$, a ``heavy axion'' associated with sextet quark electroweak
symmetry breaking, may have been seen at LEP via its two-photon decay mode and
also at TRISTAN via its hadronic decay modes. - presented at DPF 92.


title: Calculation of 130 Gev Mass for T-Quark

abstract:
  A 130 GeV mass is calculated for the t-quark, also called the truth quark or
the top quark.
  The 130 GeV T-quark mass is consistent with the analysis of Dalitz and
Goldstein (131 GeV (-11, +22 )) of a CDF T-quark candidate event [1]. It is not
consistent with the theoretical calculations of Dimopoulos, Hall, and Raby that
the T-quark mass range should be 176 to 190 GeV [2].
  The calculation uses a model in which the 28-dimensional adjoint
representation of Spin(8) forms the gauge group of the model with an
8-dimensional spacetime whose tangent vector space is represented by the vector
representation of Spin(8); the first generation fermion particles and
antiparticles are represented by the two mirror image 8-dimensional half-spinor
representations of Spin(8). The 8-dimensional spacetime of the model is reduced
to 4 dimensions. Dimensional reduction gives the fermions a 3-generation
structure.
  At request, I added a chronology including work of others.


title: Neutrinos with Mixing in Twisting Magnetic Fields

abstract:
  Transitions in a system of neutrinos with vacuum mixing and magnetic moments,
propagating in matter and transverse magnetic field, are considered. It is
shown that in the realistic case of magnetic field direction varying along the
neutrino path qualitatively new phenomena become possible: permutation of
neutrino conversion resonances, appearance of resonances in the
neutrino-antineutrino ($\nu_{lL}\leftrightarrow\bar{\nu}_{lR}$) transition
channels, neutrino-antineutrino resonant conversion, large amplitude
$\nu_{lL}\leftrightarrow\bar{\nu}_{lR}$ oscillations, merging of different
resonances (triple resonances). Possible phenomenological implications of these
effects are briefly discussed.


title: D\bar{D}$ Mixing in Heavy Quark Effective Field Theory: The Sequel

abstract:
  We perform a quantitative analysis of $D\bar{D}$ mixing in Heavy Quark
Effective Field Theory (HqEFT) including leading order QCD corrections. We find
an enhancement of the short-distance contribution by a factor of two or three.


title: Planck Scale Symmetry Breaking and Majoron Physics

abstract:
  Majoron models provide neutrino masses via the spontaneous breaking of a
global $U(1)$ symmetry. However, it may be argued that all global symmetries
will be explicitly violated by gravitational effects. We show that it is
possible to preserve most of the usual features of majoron models by invoking
$U(1)_{B-L}$ to be a gauge symmetry and adding a second singlet scalar field.
The majoron gets a small model dependent mass. The couplings of majorons to
neutrinos may be of ordinary strength or may be made arbitrarily weak. We
discuss the cosmological and astrophysical consequences of majoron models in
the context of a model dependent majoron mass and neutrino coupling. For an
appropriate choice of parameters majorons can play the role of dark matter.


title: QED Radiative Corrections to the Decay $\pi^{0} \rightarrow e^{+}e^{-}$

abstract:
  In view of the recent interest in the decays of mesons into a pair of light
leptons, a computation of the QED radiative corrections to the decay of
$\pi^{0}$ into an electron-positron pair is presented here. The results
indicate that the peak value of the differential decay rate is reduced by about
$50 \%$, because of soft-photon radiation. The number of $e^{+}e^{-}$ pairs
having invariant masses in an energy bin of 0.5 MeV centered around $m_{\pi}$
is found to be about $20 \%$ smaller than the one it would be if radiative
corrections were neglected.


title: Quark-Gluon Jet Differences at LEP

abstract:
  A new method to identify the gluon jet in 3-jet ``{\bf Y}'' decays of $Z^0$
is presented. The method is based on differences in particle multiplicity
between quark jets and gluon jets, and is more effective than tagging by
leptonic decay. An experimental test of the method and its application to a
study of the ``string effect'' are proposed. Various jet-finding schemes for
3-jet events are compared.


title: Double Pomeron Opportunities at SQRT(s) = 1.8 Tev

abstract:
  I describe possible ways to discover hard double pomeron exchange (HDPE) with
the existing detectors at the Fermilab Tevatron, by using the small-angle
``luminosity'' counters as a veto. Estimates of the cross sections and
backgrounds are made. In addition to the intrinsic importance of HDPE, its
observation would be useful for calibrating the detectors, and for estimating
the ``survival probability'' of rapidity gaps.


title: Bubble Free Energy in Cosmological Phase Transitions

abstract:
  Free energy as a function of temperature and the bubble radius is determined
for spherical bubbles created in cosmological first order phase transitions.
The phase transition is assumed to be driven by an order parameter (e.g. a
Higgs field) with quartic potential. The definition of the bubble radius and
the corresponding generalized, curvature-dependent surface tensions are
discussed. In the free energy expansion in powers of the inverse radius, the
coefficients of the curvature term and the constant term are also calculated.


title: Dilepton and photon production in the 'hot-glue' scenario

abstract:
  Perturbative analysis of parton kinetics for high energy nuclear collisions
shows, that thermal equilibration of gluons happens very fast, while quark
production is much slower. A simple 'minimal model' is proposed which includes
only in-coming quarks and anti-quarks. We have found that a smaller quark
number is more than compensated by the fact, that they are imbedded into the
hotter glue. Predicted yield of dileptons and photons in the interesting
kinematic region are larger than considered before, and are quite observable at
RHIC and LHC.


title: Chiral Corrections to Hyperon Vector Form Factors

abstract:
  We show that the leading $SU(3)$-breaking corrections to the $\Delta S = 1$
$f_1$ vector form factors of hyperons are $O(m_s)$ and $O(m_s^{3/2})$, and are
expected to be $\sim 20$--$30\%$ by dimensional analysis. This is consistent
with the Ademollo--Gatto theorem, in a sense that we explain. We compute the
$O(m_s)$ corrections and a subset of the $O(m_s^{3/2})$ corrections using an
effective lagrangian in which the baryons are treated as heavy particles. All
of these corrections are surprisingly small, $\sim 5\%$; combining them, we
obtain $\sim 5$--$10\%$ corrections. The pattern of corrections is very
different than that predicted by quark models.


title: Construction of Realistic superstring Standard--like Models

abstract:
  I discuss the construction of realistic superstring standard--like models in
the four dimensional free fermionic formulation. I discuss proton lifetime
constraints on superstring models. I discuss the massless spectrum of the
superstring standard--like models, the texture of fermion mass matrices in
these models and argue that the realistic features of these models are due to
the underlying $Z_2\times Z_2$ orbifold compactification. (talk presented at
the TEXAS\\PASCHOS conference, Berkeley CA, December 13--18 1992)


title: A possible glueball contribution to the Goldberger-Treiman relations

abstract:
  We discuss the influence of glueball coupling to nucleons on the weak
axial-vector coupling constants including singlet channel. We consider a
possibility of introduction of constituent gluon contribution to the proton
spin. The estimated value for this quantity seems to be rather small.


title: Triviality Bounds in Two-Doublet Models

abstract:
  We examine perturbatively the two-Higgs-doublet extension of the \SM\ in the
context of the suspected triviality of theories with fundamental scalars.
Requiring the model to define a consistent effective theory for scales below a
cutoff of $2\pi$ times the largest mass of the problem, as motivated by lattice
investigations of the one-Higgs-doublet model, we obtain combined bounds for
the parameters of the model. We find upper limits of 470 GeV for the mass of
the light $CP$--even neutral scalar and 650--700 GeV for the other scalar
masses.


title:
The Rate for $e^+e^-\to B B^\pm \pi^\mp$ and its Implications for the
  Study of CP Violation, $B_s$ Identification, and the Study of $B$ Meson
  Chiral Perturbation Theory

abstract:
  H.~Yamamoto has proposed employing $B$ mesons produced in conjunction with a
single charged pion at an $\Upsilon$ resonance for studies of CP violation in
the neutral $B$ meson system at a symmetric $e^+$-$e^-$ collider. The sign of
the charged pion would tag the neutral $B$ meson. We estimate this branching
ratio, employing the heavy meson chiral effective field theory. We find a
negligible branching ratio to $B B^{\pm} \pi^{\mp}$ at the $\Upsilon$(5S) and a
branching ratio of only a few percent at the $\Upsilon$(6S). However, if
nonresonant studies of neutral $B$ mesons should prove feasible, Yamamoto's
proposal could be a good method for tagging neutral $B$'s for the study of CP
violation at a symmetric collider.
  We also explore the possibility of studying $B_s$ at the $\Upsilon$(5S). The
rate is low but depends sensitively on the precise value of the mass of the
$B_s$. The background we compute is comparable to the rate at the largest
allowed value of the $B_s$ mass.
  Finally, we discuss the extraction of the axial pion coupling to $B$ mesons
from measurement of the $B\bbar\pi$ branching fraction in a restricted region
of phase space, where chiral perturbation theory should work well.


title: Measuring velocity ratios with correlation functions

abstract:
  We show how to determine the ratio of the transverse velocity of a source to
the velocity of emitted particles, using split-bin correlation functions. The
technique is to measure $S_2$ and $S_2^{\phi}$, subtract the contributions from
the single-particle distribution, and take the ratio as the bin size goes to
zero. We demonstrate the technique for two cases: each source decays into two
particles, and each source emits a large number of particles.


title: Probing CP Violation Via Higgs Decays to Four Leptons

abstract:
  Since decays to four leptons is widely considered a promising way to search
for the Higgs particle, we show how the same final state can also be used to
search for signals of CP nonconservation. Energy asymmetries and triple
correlations are related to parameters in the underlying CP violating effective
interaction at the $H^0$-$W$-$W$ and $H^0$-$Z$-$Z$ vertex. Expected size of the
effects are shown to be small for both the Sandard Model and its extension with
an extra Higgs doublet.


title:
The effects of a strongly interacting Higgs sector on
  $\gamma\,\gamma\rightarrow W_L^+\,W_L^-, Z_L^{\,0}\,Z_L^{\,0}$ scattering

abstract:
  We study the effects of a strongly interacting Higgs sector on the amplitudes
for $\gamma\,\gamma\rightarrow W_L^+\,W_L^-, Z_L^{\,0}\,Z_L^{\,0}$ by
unitarizing the $W_L^+\,W_L^-, Z_L^{\,0}\,Z_L^{\,0}, \gamma\,\gamma$ system
using the $K$--matrix technique. Unitarization produces substantial corrections
to the cross sections for gauge boson pair production by photon fusion when
$m_H \agt 5-10\;$TeV.


title: Instantons in Field Strength Formulated Yang-Mills Theories

abstract:
  It is shown that the field strength formulated Yang-Mills theory yields the
same semiclassics as the standard formulation in terms of the gauge potential.
This concerns the classical instanton solutions as well as the quantum
fluctuations around the instanton.


title:
Generation of the Baryon Asymmetry of the Universe within the
  Left--Right Symmetric Model

abstract:
  Fermions scattering off first-order phase transition bubbles, in the
framework of $SU(2)_L\otimes SU(2)_R\otimes U(1)$ models, may generate the
Baryon Asymmetry of the Universe (BAU), either at the $LR$-symmetry-breaking
scale, or at the weak scale. In the latter case, the baryon asymmetry of the
Universe is related to CP violation in the $K_0$--$\bar K_0$ system.


title:
Stranger Still: Kaon Loops and Strange Quark Matrix Elements of the
  Nucleon

abstract:
  Intrinsic strangeness contributions to low-energy strange quark matrix
elements of the nucleon are modelled using kaon loops and meson-nucleon vertex
functions taken from nucleon-nucleon and nucleon-hyperon scattering. A
comparison with pion loop contributions to the nucleon electromagnetic (EM)
form factors indicates the presence of significant SU(3)-breaking in the
mean-square charge radii. As a numerical consequence, the kaon loop
contribution to the mean square Dirac strangeness radius is significantly
smaller than could be observed with parity-violating elastic ep experiments
planned for CEBAF, while the contribution to the Sachs radius is large enough
to be observed with PV electron scattering from (0^+,0) nuclei. Kaon loops
generate a strange magnetic moment of the same scale as the isoscalar EM
magnetic moment and a strange axial vector form factor having roughly one-third
magnitude extracted from nu p/nubar p elastic scattering. In the chiral limit,
the loop contribution to the fraction of the nucleon's scalar density arising
from strange quarks has roughly the same magnitude as the value extracted from
analyses of Sigma_{\pi N}. The importance of satisfying the Ward-Takahashi
Identity, not obeyed by previous calculations, is also illustrated, and the
sensitivity of results to input parameters is analyzed.


title: Instanton Condensation in Field Strength Formulated QCD

abstract:
  Field strength formulated Yang-Mills theory is confronted with the
traditional formulation in terms of gauge fields. It is shown that both
formulations yield the same semiclassics, in particular the same instanton
physics. However, at the tree level the field strength approach is superior
because it already includes a good deal of of quantum fluctuations of the
standard formulation. These quantum fluctuations break the scale invariance of
classical QCD and give rise to an instanton interaction and this causes the
instantons to condense and form a homogeneous instanton solid. Such the
instanton solids show up in the field strength approach as homogeneous
(constant up to gauge transformations) vacuum solutions. A new class of SU(N)
instantons is presented which are not embeddings of SU(N-1) instantons but have
non-trivial SU(N) color structure and carry winding number $n=N(N^{2}-1)/6$.
These instantons generate (after condensation) the lowest action solutions of
the field strength approach. The statistical weight (entropy) of different
homogeneous solutions for SU(3) is numerically estimated by Parisi's stochastic
quantization method. Finally, we compare instanton induced quark condensation
with the condensation of quarks in the homogeneous field strength solutions.
Our investigations show that the homogeneous vacuum of the field strength
approach simulates in an efficient way a condensate of instantons.


title: Massive neutrinos and electroweak baryogenesis

abstract:
  We show that certain models for neutrino masses that lead to the MSW
explanation of the solar neutrino data and/or the hot dark matter component in
the universe can also naturally allow for the successful generation of the
cosmological baryon asymmetry at the electroweak scale. This follows either
because the experimental Higgs boson mass limit is weakened due to the smaller
production rate and the presence of sizeable invisible decays involving majoron
emission, or due to the effect of additional electrically charged scalar bosons
which substantially modify the condition for succesful baryogenesis.


title: Heavy Charged Leptons in an $SU(3)_L\otimes U(1)_N$ Model

abstract:
  We consider an $SU(3)_L\otimes U(1)_N$ model for the electroweak interactions
which includes extra charged leptons which do not mix with the known leptons.
These new leptons couple to $Z^0$ only through vector currents. We consider
constraints on the mass of one of these leptons coming from the $Z^0$-width and
from the muon $(g-2)$ factor. The last one is less restrictive than the former.


title: Nucleon Form Factors in a Relativistic Quark Model

abstract:
  We demonstrate that a relativistic constituent-quark model can give nucleon
form factors in agreement with data for both low and high momentum transfer.
The relativistic features of the model and the specific form of the wave
function are essential for the result.


title: Color--Sextet Quark Condensation in QCD

abstract:
  We suggest that the sextet color condensation model is not only the simplest
and most attractive scheme to modify the standard model but also may already
have some ``experimental" support. The crucial test may be to observe a short--
lived axion--like $\eta_6$ of mass around 60 GeV/$c^2$ that can produce high
energy photon pairs diffractively at hadron colliders and also radiatively from
$Z^0$ at high energy $e^+ e^-$ colliders. Here we show how high--energy forward
scattering can be affected by diffractive production of the $\eta_6$. Presented
to the DPF-92 meeting.


title: The Singlet Majoron Model with Hidden Scale Invariance

abstract:
  We investigate an extension of the Singlet Majoron Model in which the
breaking of dilatation symmetry by the mass parameters of the scalar potential
is removed by means of a dilaton field. Starting from the one-loop
renormalization group improved potential, we discuss the ground state of the
theory. The flat direction in the classical potential is lifted by quantum
corrections and the true vacua are found. Studying the finite temperature
potential, we analyze the cosmological consequences of a Jordan-Brans-Dicke
dilaton and show that the lepton number is spontaneously broken after the
electroweak phase transition, thus avoiding any constraint coming from the
requirement of the preservation of the baryon asymmetry in the early Universe.
We also find that, contrary to the Standard Model case, the dilaton cosmology
does not impose any upper bound on the scale of the spontaneous breaking of
scale invariance.


title:
Kinetic Equations for Longwavelength Excitations of the Quark-Gluon
  Plasma

abstract:
  We show that longwavelength excitations of the quark-gluon plasma are
described by simple kinetic equations which represent the exact equations of
motion at leading order in $g$. Properties of the so-called ``hard thermal
loops'', i.e. the dominant contributions to amplitudes with soft external
lines, find in this approach a natural explanation. In particular, their
generating functional appears here as the effective action describing long
wavelength excitations of the plasma.


title: QCD corrections to the charged Higgs decay of a heavy quark

abstract:
  We present an analytic formula for the $O(\alpha_s)$ corrections to the decay
$t\to H^+b$ for nonzero $m_H$ and $m_b$. The Equivalence Theorem is used to
relate these corrections to those for the process $t\to W^+b$. Contrary to
previously published results we find that the effect of the $b$ quark mass is
negligible for a wide range of $m_t$, $m_H$ and $\tan \beta$.


title:
W + gamma + jet production as a test of the electromagnetic couplings of
  W at LHC and SSC

abstract:
  The reaction $pp \to W \ +\ \gamma\ +\ jet \ +\ X$ is considered at
centre-of-mass energies $\sqrt{s} = 16$ and $40\;\tev$, including anomalous
three-gauge-boson couplings $\kappa$ and $\lambda$. The possibility of
obtaining limits on these quantities by comparison with the standard model is
investigated. The radiation zero properties of the subprocess matrix elements
are studied. CERN-TH.6753/92, DTP/92/92.


title:
Implications of Gallium Solar Neutrino Data for the Resonant Spin-Flavor
  Precession Scenario

abstract:
  We consider the implications of the recent results of SAGE and GALLEX
experiments for the solution of the solar neutrino problem in the framework of
the resonant neutrino spin-flavor precession scenario. It is shown that this
scenario is consistent with all the existing solar neutrino data including the
gallium results. The quality of the fit of the data depends crucially on the
magnetic field profile used which makes it possible to get information about
the magnetic field in the solar interior. In particular, the magnetic field in
the core of the sun must not be too strong ($<3 \times 10^6$ G). The detection
rate in the gallium detectors turns out to be especially sensitive to the
magnitude of $\Delta m^2$. Predictions for forthcoming solar-neutrino
experiments are made.


title: Gravity and Domain Wall Problem

abstract:
  It is well known that the spontaneous breaking of discrete symmetries may
lead to conflict with big-bang cosmology. This is due to formation of domain
walls which give unacceptable contribution to the energy density of the
universe. On the other hand it is expected that gravity breaks global
symmetries explicitly. In this work we propose that this could provide a
natural solution to the domain-wall problem.


title: Study of the Reactions $B \to D^* \pi \pi$ and $B \to D^* \rho \pi$

abstract:
  We evaluate the non leptonic decays $B \to D^* \pi \pi$ and $B \to D^* \rho
\pi$ in the limit of infinitely heavy quarks, assuming the dominance of
intermediate positive parity charmed resonances. We find that the branching
ratios are of the order $10^(-3)$.


title: Nonabelian Berry Phases in Baryons

abstract:
  We show how generic nonabelian gauge fields can be induced in baryons when a
hierarchy of fast degrees of freedom is integrated out. We identify them with
nonabelian Berry potentials and discuss their role in transmuting quantum
numbers in bag and soliton models of baryons. The resulting baryonic spectra
for both light and heavy quark systems are generic and resemble closely the
excitation spectrum of diatomic molecules. The symmetry restoration in the
system, i.e., the electronic rotational invariance in diatomic molecules, the
heavy-quark symmetry in heavy baryons etc. is interpreted in terms of the
vanishing of nonabelian Berry potentials that otherwise govern the hyperfine
splitting.


title: Implications of Solar and Atmospheric Neutrinos

abstract:
  The implications of the deficit of solar neutrinos are discussed. If all of
the experiments are taken literally the relative suppressions render an
astrophysical explanation unlikely. Allowing MSW conversions, the data
simultaneously determine the temperature of the core of the sun to within five
percent. The implications of the atmospheric $\nu_\mu/\nu_e$ ratio are briefly
discussed.


title: What $\pi-\pi$ Scattering Tells Us About Chiral Perturbation Theory

abstract:
  We describe a rearrangement of the standard expansion of the symmetry
breaking part of the QCD effective Lagrangian that includes into each order
additional terms which in the standard chiral perturbation theory ($\chi$PT)
are relegated to higher orders. The new expansion represents a systematic and
unambiguous generalization of the standard $\chi$PT, and is more likely to
converge rapidly. It provides a consistent framework for a measurement of the
importance of additional ``higher order'' terms whose smallness is usually
assumed but has never been checked. A method of measuring, among other
quantities, the QCD parameters $\hat{m}\langle\bar{q}q\rangle$ and the quark
mass ratio $m_s/\hat{m}$ is elaborated in detail. The method is illustrated
using various sets of available data. Both of these parameters might be
considerably smaller than their respective leading order standard $\chi$PT
values. The importance of new, more accurate, experimental information on
low-energy $\pi-\pi$ scattering is stressed.


title: Symmetry Remnants: Rationale for Having Two Higgs Doublets

abstract:
  There is a good reason why the standard electroweak SU(2) X U(1) gauge model
may be supplemented by two Higgs scalar doublets. They may be remnants of the
spontaneous breaking of an SU(2) X SU(2) X U(1) gauge symmetry at a much higher
energy scale. In one case, the two-doublet Higgs potential has a custodial
SU(2) symmetry and implies an observable scalar triplet. In another, a light
neutral scalar becomes possible.


title: Quark Models and Quark Phenomenology

abstract:
  Overwhelming experimental evidence for quarks as real physical constituents
of hadrons along with the QCD analogs of the Balmer Formula, Bohr Atom and
Schroedinger Equation already existed in 1966. A model of colored quarks
interacting with a one-gluon-exchange potential explained the systematics of
the meson and baryon spectrum and gave a hadron mass formula in surprising
agreement with experiment. The simple quark model dismissed as heresy and
witchcraft by the establishment predicted quantum numbers of an enormous number
of hadronic states as well as relations between masses, reaction cross sections
and electromagnetic properties, all unexplained by other approaches. Further
developments leading to QCD included confinement in the large $N_c$ limit,
duality, dual resonance and string models, high energy scattering systematics,
unified treatment of mesons and baryons, no exotics and no free quarks.


title: Pontecorvo's Original Oscillations Revisited

abstract:
  We show that a left-handed neutrino $\nu_L$ can oscillate into its $CP$-
conjugated state $\bar{\nu}_R$ with maximal amplitude, in direct analogy with
$K^0-\bar{K}^0$ oscillations. Peculiarities of such oscillations under
different conditions are studied.


title: Fermion Masses in SO(10)

abstract:
  Yukawa coupling constant unification together with the known fermion masses
is used to constrain SO(10) models. We consider the case of one (heavy)
generation, with the tree-level relation $m_b=m_\tau$, calculating the limits
on the intermediate symmetry breaking scales. This analysis extends previous
analyses which addressed only the simplest symmetry breaking schemes. In the
case where the low energy model is the standard model with one Higgs doublet,
there are very strong constraints due to the known limits on the top mass and
the tau neutrino mass. The two Higgs doublet case is less constrained. Finally
we address the role of a speculative constraint on the tau neutrino mass,
arising from the cosmological implications of anomalous $B+L$ violation in the
early universe.


title: Is Upsilon(3S) a pure S-wave?

abstract:
  Assuming the QCD multipole expansion is applicable to hadronic transitions of
Upsilon(3S) into lower level bottomonia, we consider the possibility that
Upsilon(3S) has a D-wave component. This assumption leads to a natural
explanation of the pi-pi spectrum in Upsilon(3S) -> Upsilon(1S) pi-pi.
Consequences of this assumption on other hadronic and radiative transitions of
Upsilon(3S) are also discussed in the same context.


title: Casimir forces between beads on strings

abstract:
  We consider a string with uniform energy density and tension and with a
number of pointlike masses attached at fixed interdistances. We evaluate the
effective interaction forces between these masses induced by the quantum
fluctuations of the string. For interdistances large compared to the thickness
of the string and small compared to the total length, these forces are
universal and attractive and fall off, for large distances as $1/r^3$ and for
small distances as $1/r$. The attractive nature of these forces creates an
instability under which masses added to the string tend to aggregate.


title: The $\eta_6$ at LEP and TRISTAN

abstract:
  The $\eta_6$ is a ``heavy axion'' remnant of dynamical electroweak symmetry
breaking by a color sextet quark condensate. Electroweak scale color instanton
interactions allow it to be both very massive and yet be responsible for Strong
CP conservation in the color triplet quark sector. It may have been seen at LEP
via its two-photon decay mode and at TRISTAN via its hadronic decay modes.


title: Detection of the heavy Higgs boson at $\gamma\gamma$ colliders

abstract:
  We consider the possibility of detecting a heavy Higgs boson ($m_H>2m_Z$) in
proposed $\gamma\gamma$ colliders through the semi-leptonic mode $\gamma\gamma
\rightarrow H \rightarrow ZZ \rightarrow q\bar q \ell^+\ell^-$. We show that
due to the non-monochromatic nature of the photon beams produced by the
laser-backscattering method, the resultant cross section for Higgs production
is much smaller than the on-resonance cross section and generally {\it
decreases} with increasing collider energy. Although continuum $ZZ$ production
is expected to be negligible, we demonstrate the presence of and calculate
sizeable backgrounds from $\gamma\gamma\rightarrow \ell^+\ell^-Z,\,q\bar qZ$,
with $Z\rightarrow q\bar q,\,\ell^+\ell^-$, respectively, and
$\gamma\gamma\rightarrow t\bar t\rightarrow b\bar b\ell^+\ell^-\nu\bar\nu$.
This channel may be used to detect a Higgs of mass $m_H$ up to around 350~GeV
at a 0.5~TeV $e^+e^-$ collider, assuming a nominal yearly luminosity of
10--20~fb$^{-1}$.


title:
Scalar Mesons in $\phi$ Radiative Decay: their implications for
  spectroscopy and for studies of CP-violation at $\phi$ factories

abstract:
  Existing predictions for the branching ratio for $\phi\rightarrow
K\bar{K}\gamma$ {\it via} $\phi\rightarrow S\gamma$ (where $S$ denotes one of
the scalar mesons $f_0$(975) and $a_0$(980)) vary by several orders of
magnitude. Given the importance of these processes for both hadron spectroscopy
and CP-violation studies at $\phi$ factories (where $\phi \rightarrow K^0 \bar
K^0 \gamma$ poses a possible background problem), this state of affairs is very
undesirable. We show that the variety of predictions is due in part to errors
and in part to differences in modelling. The latter variation leads us to argue
that the radiative decays of these scalar states are interesting in their own
right and may offer unique insights into the nature of the scalar mesons. As a
byproduct we find that the branching ratio for $\phi\rightarrow
K^0\bar{K}^0\gamma$ is $\lapproxeq 0(10^{-7})$ and will pose no significant
background to proposed studies of CP-violation.


title: Next to leading order determination of pion fragmentation functions

abstract:
  We perform a complete next to leading order evaluation of inclusive neutral
pion production from hadronic colliders which is based on the knowledge of the
pion fragmentation functions at next to leading order. This problem has been
tackled for the first time using different approaches. Predictions at LHC are
given with the estimate of the theoretical uncertainty.


title:
Calculation of processes involving many particles at the kinematical
  threshold

abstract:
  A diagrammatic technique is derived for calculating processes involving the
production of large numbers of particles. As an example, the amplitude of three
particles scattering into $n$ particles at the kinematical threshold in
$\lambda\phi^4$ theory is calculated. From the $3 \to n$ amplitude, it is seen
that the one-loop amplitude for $2 \to n$ processes is suppressed by a factor
of $1/n$.


title:
Chiral Dynamics and Fermion Mass Generation in Three Dimensional Gauge
  Theory

abstract:
  We examine the possibility of fermion mass generation in 2+1- dimensional
gauge theory from the current algebra point of view.In our approach the
critical behavior is governed by the fluctuations of pions which are the
Goldstone bosons for chiral symmetry breaking. Our analysis supports the
existence of an upper critical number of Fermion flavors and exhibits the
explicit form of the gap equation as well as the form of the critical exponent
for the inverse correlation lenght of the order parameter


title: Delta-Isobar Magnetic Form Factor in QCD

abstract:
  We consider the QCD sum rules approach for Delta-isobar magnetic form factor
in the infra-red region $0<Q^2<1GeV^2$. The QCD sum rules in external variable
field are used. The obtained formfactor is in agreement with quark model
predictions for the Delta-isobar magnetic moment.


title:
Third Generation Effects on Fermion Mass Predictions in Supersymmetric
  Grand Unified Theories

abstract:
  Relations among fermion masses and mixing angles at the scale of grand
unification are modified at lower energies by renormalization group running
induced by gauge and Yukawa couplings. In supersymmetric theories, the $b$
quark and $\tau$ lepton Yukawa couplings, as well as the $t$ quark coupling,
may cause significant running if $\tan \beta$, the ratio of Higgs field
expectation values, is large. We present approximate analytic expressions for
the scaling factors for fermion masses and CKM matrix elements induced by all
three third generation Yukawa couplings. We then determine how running caused
by the third generation of fermions affects the predictions arising from three
possible forms for the Yukawa coupling matrices at the GUT scale: the
Georgi-Jarlskog, Giudice, and Fritzsch textures.


title: CP Violation in top pair production at an e^+e^- collider

abstract:
  We investigate possible CP violating effects in $e^+e^-$ annihilation into
top quark pairs. One of the interesting observable effects is the difference in
production rates between the two CP conjugate polarized states $t_L\bar t_L$
and $t_R\bar t_R$. The result is an asymmetry in the energy spectra of the
lepton and the anti-lepton from the heavy quark decays. Another CP-odd
observable is the up-down asymmetry of the leptons with respect to the reaction
plane. These two asymmetries measure complementarily the absorptive and
dispersive form factors of the electric dipole moment. Finally, as an
illustration, we calculate the size of the CP violating form factors in a model
where the CP nonconservation originates from the Yukawa couplings of a neutral
Higgs boson.


title: Gravitational Laser Back-Scattering

abstract:
  A possible way of producing gravitons in the laboratory is investigated. We
evaluate the cross section electron + photon $\rightarrow$ electron + graviton
in the framework of linearized gravitation, and analyse this reaction
considering the photon coming either from a laser beam or from a Compton
back-scattering process.


title: Cabibbo Mixing in Superstring Derived Standard--like Models

abstract:
  We examine the problem of generation mixing in realistic superstring derived
standard--like models, constructed in the free fermionic formulation. We study
the possible sources of family mixing in these models . In a specific model we
estimate the Cabibbo angle. We argue that a Cabibbo angle of the correct order
of magnitude can be obtained in these models.


title: Nuclear Gluon Distributions in a Parton Model

abstract:
  Gluon distributions in the carbon and tin nuclei are investigated by using a
$Q^2$ rescaling model with parton recombination effects. We obtain strong
shadowings in the small $x$ region due to the recombinations. The ratio
$G_A(x)/G_N(x)$ in the medium $x$ region is typically 0.9 for medium size
nuclei. At large $x$, the ratio becomes large due to gluon fusions from
different nucleons. Comparisons with recent New Muon Collaboration data for
$G_{Sn} (x)/ G_C (x)$ indicate that more accurate experimental data are needed
for testing the model.


title:
High-Energy Cosmic-Ray Muons Under Thick Layers of Matter I. a Method to
  Solve the Transport Equation

abstract:
  An effective analytical method for calculating energy spectra of cosmic-ray
muons at large depths of homogeneous media is developed. The method allows to
include an arbitrary (decreasing) muon spectrum at the medium boundary and the
energy dependence of both discrete (radiative and photonuclear) and continuous
(ionization) muon energy losses, with resonable requirements for the
high-energy behavior of the initial spectrum and differential cross sections of
the muon-matter interactions. (To be published in the Proceedings of the Second
NESTOR International Workshop, 19 -- 21 October 1992, Pylos, Greece.)


title:
Rare K-Decays as Crucial Tests for Unified Models with Gauged Baryon
  Number:

abstract:
  In the grand-unified models based on SU(15) and SU(16) in which the quarks
and leptons are un-unified at the intermediate stages, we show that ${\rm BR}\;
(K_L \to \mu e) \leq 10^{-14}$ and ${\rm BR}\; (K^+ \to \pi^+\mu e) \leq
10^{-14}$ despite the presence of leptoquark gauge bosons. Thus, the
observation of these processes in the ongoing or upcoming experiments will rule
out the models.


title:
CP Violation in the Decay of Neutral Higgs Boson into $t-{\bar t}$ or
  $W^+-W^-$

abstract:
  We investigate a potentially large CP violating asymmetry in the neutral
Higgs boson decay into a heavy quark pair or a $W^+$--$W^-$ pair. The source of
the CP nonconservation is in the Yukawa couplings of the Higgs boson which can
contain both scalar and pseudoscalar pieces. One of the interesting consequence
is the different rates of the Higgs boson decays into CP conjugate polarized
states. The required final state interactions can be either the strong or the
electroweak interactions. The CP violating asymmetry can manifests itself in
the asymmetry in the energies of the secondary decay products of these heavy
quarks and $W$ bosons. Such asymmetry can be measureable in the future
colliders such as SSC or LHC.


title:
Fermion Density Induced Instability of the W-Boson Pair Condensate in
  Strong Magnetic Field

abstract:
  The electroweak vacuum structure in an external magnetic field close to the
lower critical value is considered at finite fermion density. It is shown that
the leading effect of the fermions is to reduce the symmetry of the W-pair
condensate in the direction of the magnetic field. The energy is minimized by
the appearance of a helicoidal structure of the condensate along the magnetic
field.


title:
Implications for Minimal Supersymmetry from Grand Unification and the
  Neutralino Relic Abundance

abstract:
  We examine various predictions of the minimal supersymmetric standard model
coupled to minimal supergravity. The model is characterised by a small set of
parameters at the unification scale. The supersymmetric particle spectrum at
low energy and the spontaneous breaking of the standard model itself are then
generated radiatively. The previously considered predictions of the model now
include the neutralino relic density which in turn provides bounds on the scale
parameters. We find a remarkable consistency among several different
constraints which imply all supersymmetric particle masses preferably within
the reach of future supercolliders (LHC and SSC). The requirement that the
neutralino be the dominant component of (dark) matter in the flat Universe
provides a {\em lower} bound on the spectrum of supersymmetric particles beyond
the reach of LEP, and most likely also the Tevatron and LEP 200.


title: Gauge Coupling Unification in Superstring Derived Standard--like Models

abstract:
  I discuss gauge coupling unification in a class of superstring standard--like
models, which are derived in the free fermionic formulation. Recent
calculations indicate that the superstring unification scale is at
$O(10^{18}GeV)$ while the minimal supersymmetric standard model is consistent
with LEP data if the unification scale is at $O(10^{16})GeV$. A generic feature
of the superstring standard--like models is the appearance of extra color
triplets $(D,{\bar D})$, and electroweak doublets $(\ell,{\bar\ell})$, in
vector--like representations, beyond the minimal supersymmetric standard model.
I show that gauge coupling unification at $O(10^{18}GeV)$ in the superstring
standard--like models can be consistent with LEP data. I present an explicit
standard--like model that can realize superstring gauge coupling unification.


title: Soft Modes Contribution into Path Integral

abstract:
  A method for nonperturbative path integral calculation is proposed.
  Quantum mechanics as a simplest example of a quantum field theory is
considered. All modes are decomposed into hard (with frequencies $\omega^2
>\omega^2_0$) and soft (with frequencies $\omega^2 <\omega^2_0$) ones,
$\omega_0$ is a some parameter. Hard modes contribution is considered by weak
coupling expansion. A low energy effective Lagrangian for soft modes is used.
In the case of soft modes we apply a strong coupling expansion. To realize this
expansion a special basis in functional space of trajectories is considered. A
good convergency of proposed procedure in the case of potential $V(x)=\lambda
x^4$ is demonstrated. Ground state energy of the unharmonic oscillator is
calculated.


title: Application of M\"ossbauer-Type Sum Rules for $B$ Meson Decays

abstract:
  Sum rules originally derived for the M\"ossbauer Effect are applied to weak
semileptonic B decays. The sum rules follow from assuming that the decay by
electroweak boson emission of an unstable nucleus or heavy quark in a bound
system is described by a pointlike coupling to a current which acts only on the
decaying object, that the Hamiltonian of the bound state depends on the
momentum of the decaying object only in the kinetic energy and that the boson
has no final state interactions. The decay rate and the first and second
moments of the boson energy spectrum for fixed momentum transfer are shown to
be the same as for a noninteracting gas of such unstable objects with a
momentum distribution the same as that of the bound state. B meson semileptonic
decays are shown to be dominated by the lowest-lying states in the charmed
meson spectrum.


title:
The Large N Limit and the High Temperature Phase Transition for the
  \phi^4 Theory

abstract:
  We study, with various methods (standard large N evaluation of the functional
integral for the effective potential, solution of the Schwinger-Dyson
equations), the high temperature phase transition for the $N$-component
$\phi^4$ theory in the large $N$ limit. Our results fully confirm a previous
investigation of the problem, for arbitrary $N$, with the method of the average
potential which employs renormalization group ideas. The phase transition is of
the second order with an effectively three-dimensional critical behaviour. }


title: CP-Violation with Bosons

abstract:
  We formulate the conditions under which a purely bosonic theory (without
fermions) containing neutral spin-0 particles and vector (gauge) bosons
violates the CP-symmetry through the presence of CP-even and CP-odd operators
in the Lagrangian. This is done without reference to explicitly CP-violating
scalar sector of extended standard models (SM) with two or more Higgs doublets.
The Lagrangian expressed in the mass basis of the spin-0 fields can, however,
in certain cirumstances be identified with a part of the CP-violating SM with
two Higgs doublets. It is instructive to consider the manifestation of
CP-violation in the mass basis since this leads directly to suggestions of
genuine CP-signals.


title: CP-odd Neutral Higgs Effects in Top -- anti-Top Production

abstract:
  We study $CP$ violation in the process $e^+e^- \to t\bar{t} \nu\bar{\nu}$ at
an $e^+e^-$-TeV collider. As the source of $CP$ violation we assume a two-Higgs
doublet model with an explicitly $CP$-noninvariant Higgs potential. Sizeable
$CP$-odd observables originating from the subprocess reaction, $W^+W^- \to
t\bar{t}$, may arise as a result of finite width effects of the neutral Higgs
particles. $CPT$ constraints due to final (initial) state interactions are also
taken into account. Numerical estimates of the $CP$ asymmetry are given.


title: QCD Sum Rules and Compton Scattering

abstract:
  We extend QCD sum rule analysis to moderate energy fixed angle Compton
scattering. In this kinematic region there is a strong similarity to the sum
rule treatment of electromagnetic form factors, although the four-point
amplitude requires a modification of the Borel transform. To illustrate our
method, we derive the sum rules for helicity amplitudes in pion Compton
scattering and estimate their large-$t$ behavior in the local duality
approximation.


title: The phase-space structure of the Klein-Gordon field

abstract:
  The formalism based on the equal-time Wigner function of the two-point
correlation function for a quantized Klein--Gordon field is presented. The
notion of the gauge-invariant Wigner transform is introduced and equations for
the corresponding phase-space calculus are formulated. The equations of motion
governing the Wigner function of the Klein--Gordon field are derived. It is
shown that they lead to a relativistic transport equation with electric and
magnetic forces and quantum corrections. The governing equations are much
simpler than in the fermionic case which has been treated earlier. In addition
the newly developed formalism is applied towards the description of spontaneous
symmetry breakdown.


title:
A global fit of $\pi\pi$ and $\pi K$ elastic scattering in ChPT with
  dispersion relations

abstract:
  We apply the one-loop results of the $SU(3)_L\times SU(3)_R$ ChPT suplemented
with the inverse amplitude method to fit the available experimental data on
$\pi\pi$ and $\pi K$ scattering. With esentially only three parameters we
describe accurately data corresponding to six different channels, namely
$(I,J)=(0,0), (2,0), (1,1), (1/2,0), (3/2,0)$ and $(1/2,1)$. In addition we
reproduce the first resonances of the $(1,1)$ and $(1/2,1)$ channel with the
right mass corresponding to the $\rho$ and the $K^*(892)$ particles.


title:
Operator Analysis for the Higgs Potential and Cosmological Bound on the
  Higgs-Boson Mass

abstract:
  Using effective lagrangian, we examine the impacts of new physics on the
electroweak baryogenesis. By analysing the high dimensional operators relevent
to the Higgs potential we point out that the Higgs mass bound required by
electroweak baryogenesis can be relaxed to the region allowed by experiments,
provided that new physics appears at the TeV scale.


title: The Rare Decay $B\to K^{\ast}\gamma$: A More Precise Calculation

abstract:
  Efforts to predict the rare exclusive decay $B\to K^{\ast}\gamma$ from the
well known inclusive decay $b\to s\gamma$ are frustrated by the effect of the
large recoil momentum. We show how to reduce the large uncertainty in
calculating this decay by relating $B\to K^{\ast}\gamma$ to the semileptonic
process $B\to\rho e\bar{\nu}$ using the heavy-quark symmetry in B decays and
SU(3) flavor symmetry. A direct measurement of the $q^{2}$-spectrum for the
semileptonic decay can provide accurate information for the exclusive rare
decay.


title: Nonleptonic Decays of Charmed Mesons into two Pseudoscalar Mesons

abstract:
  We investigate the nonleptonic decay of charmed meson into two pseudoscalar
mesons using the vector--dominance model, and compare the results with those
obtained from the factorization model. In particular, we discuss the role of
the annihilation diagrams in the two models.


title:
Breaking Of Conformal Invariance And Electromagnetic Field Generation In
  The Universe

abstract:
  It is shown that the breaking of the conformal invariance in quantum
electrodynamics due to the trace anomaly results in the generation of long wave
electromagnetic fields during inflationary stage of the universe evolution. If
the coefficient of the logarithmic charge renormalization is large (due to a
large number of charged particles species), these primordial electromagnetic
fields can be strong enough to create the observed galactic magnetic fields.


title: The Chiral Approach to the Electroweak Interactions

abstract:
  The effective lagrangian approach is reviewed and applied to the case of
electroweak interactions.


title:
Interference Effects in B-Decays to Flavor-Mixed Neutral Mesons - Clues
  to Small Amplitudes and CP-Violation

abstract:
  CP violation can be observed in B decays when a given process depends upon
interference between two weak amplitudes which have different $CP$-violating
phases. Since most weak decay diagrams have quark lines where each has a
definite flavor label, neutral mesons which are flavor mixtures are
particularly interesting. Different diagrams can contribute to the different
flavor components of the meson, and the wave function itself provides
interference.


title: Dominant Three-Body Decays of a Heavy Higgs and Top Quark

abstract:
  We calculate the dominant three body Higgs decays, $H \to W^+W^-(Z^0,
\gamma)$ and $H \to t\overline{t}(Z^0,\gamma ,g)$, in the Standard Model. We
find that the branching ratios of these decays are of the order of few percent
for large Higgs masses. We comment on the behaviour of the partial decay width
$\Gamma (H \to t\overline{b}W^-)$ below the $t\overline{t}$ threshold.
Numerical results of the following three body top decays, $t \to W^+b(\gamma
,g,Z^0)$ and $t \to W^+bH$, are also given. We discuss the feasibility of
observing these Higgs and top decays at future high energy colliders.


title:
Pair creation in transport equations using the equal-time Wigner
  function

abstract:
  Based on the equal-time Wigner function for the Klein-Gordon field, we
discuss analytically the mechanism of pair creation in a classical
electromagnetic field including back-reaction. It is shown that the equations
of motion for the Wigner function can be reduced to a variable-frequency
oscillator. The pair-creation rate results then from a calculation analogous to
barrier penetration in nonrelativistic quantum mechanics. The Wigner function
allows one to utilize this treatment for the formulation of an effective
transport theory for the back-reaction problem with a pair-creation source term
including Bose enhancement.


title: The electroweak phase transition with a singlet

abstract:
  We study the electroweak phase transition in the minimal extension of the
Standard Model: an extra complex singlet with zero vacuum expectation value.
The first-order phase transition is strengthened by the cubic term triggered in
the one-loop effective potential by the extra boson. Plasma effects are
considered to leading order: they shield the cubic terms and weaken the
first-order phase transition. We find a region in the parameter space where
baryon asymmetry washout is avoided for Higgs masses consistent with present
experimental bounds. However in that region the theory becomes non-perturbative
for scales higher than $10^{10}\ GeV$.


title:
Restrictions on B-L Symmetry Breaking Implied by a Fourth Generation
  Neutrino

abstract:
  Several misprints in the earlier version (hep-ph/9301286) have been
corrected.


title: Family Symmetry, Fermion Mass Matrices and Cosmic Texture

abstract:
  The observed replication of fermions in three families is undoubtedly a
reflection of a deeper symmetry underlying the standard model. In this paper we
investigate one very elementary possibility, that physics above the grand
unification scale is described by the symmetry group $G\timesSU(3)_{fam}$ with
$G$ a gauged grand unified group, and $SU(3)_{fam}$ a global family symmetry.
The breaking of this symmetry at the GUT scale produces global texture,
providing a mechanism for structure formation in the universe, and sets strong
constraints on the low energy fermion mass matrix. With the addition of a ${\bf
45}$ Higgs and certain assumptions about the relative strength of Higgs
couplings, the simplest $SU(5)$ theory yields an eight parameter form for the
fermion mass matrices, which we show is consistent with the thirteen observable
masses and mixing angles. We discuss the natural suppression of flavour
changing neutral currents (FCNCs) and emphasise the rich low energy Higgs
sector. With minor assumptions, the theory unifies consistently with the recent
LEP data. We consider the extension to $G=SO(10)$, where some simplification
and further predictiveness emerges. Finally we discuss the dynamics of
$SU(3)_{fam}$ texture and show that the known constraints on unification
`predict' a GUT symmetry breaking scale of the order required for cosmic
structure formation, and by the recent detection of cosmic microwave anisotropy
by COBE.


title:
$WZ$, $W\gamma$, $WW$ and $ZZ$ pair productions at TeV $e\gamma$
  colliders

abstract:
  We calculate the gauge-boson pairs $W^-Z$, $W^-\gamma$, $W^+W^-$, $ZZ$
productions in the $e^- \gamma$ collisions, where the photon beam is realized
by the laser back-scattering method. These processes are important tests for
the non-abelian gauge sector of the standard model (SM). Precise calculations
of these processes can therefore probe the anomalous gauge-boson interactions.
Besides, these processes are important potential backgrounds for the
intermediate mass Higgs (IMH) search in the $e\gamma\rightarrow WH\nu$
production.


title: Leptonic CP Asymmetries in Flavor-changing H0 Decays

abstract:
  Leptonic flavor-changing $H^0$ decays with branching ratios of the order of
$10^{-5}-10^{-6}$ may constitute an interesting framework when looking for
large $CP$-violating effects. We show that leptonic $CP$~asymmetries of an
intermediate $H^0$ boson can be fairly large in natural scenarios of the
minimal Standard Model ($SM$) with right-handed neutrinos, at a level that may
be probed at future $H^0$~factories.


title:
Leptonic Flavor-changing Z0 Decays in SU(2)xU(1) Theories with Right-
  handed Neutrinos

abstract:
  We analyze possible lepton-flavor-violating decays of the $Z^0$ particle in a
minimal extension of the Standard Model, in which one right-handed neutral
field for each family has been introduced. Such rare leptonic decays are
induced by Majorana neutrinos at the first electroweak loop level and are
generally not suppressed by the ordinary "see-saw" mechanism. In particular, we
find that experimental bounds on branching ratios of the order of
$10^{-5}-10^{-6}$ attainable at $LEP$ may impose constraints on
lepton-flavor-mixing parameters and the masses of the heavy Majorana neutrinos.


title: Neutrino Masses in Flipped SU(5)

abstract:
  We analyse the fermion masses and mixings in the flipped SU(5) model. The
fermion mass matrices are evolved from the GUT scale down to $m_W$ by solving
the renormalization group equations for the Yukawa couplings. The constraints
imposed by the charged fermion data are then utilised to make predictions about
the neutrino properties . It is found that the {\it generalized } see-saw
mechanism which occurs naturally in this model can provide {\it i})a solution
to the solar neutrino problem via the MSW mechanism and {\it ii})a sufficiently
large $\nu _{\tau }$ mass to contribute as a hot dark matter component as
indicated by the recent COBE data.


title: Indications for a Detonating Quark-Gluon Plasma

abstract:
  We propose a mechanism which naturally contains the relation $\mu_{B} =
3\mu_{S}$ of the hadronic gas produced in heavy-ion collisions at CERN. Our
starting assumption is the existence of a sharp front separating the
quark-gluon plasma phase from the hadronic phase. Energy-momentum conservation
across the front leads to the following consequences for an adiabatic process
a) The baryon chemical potential, $\mu_{B}$, is approximately continuous across
the front. b) The temperature in the hadronic gas is higher than the phase
transition temperature due to superheating. c) In the region covered by the
experiments the velocity of the hadronic gas approximately equals the speed of
sound in the hadronic gas.


title: The Electric Dipole Moment of the W and Electron in the Standard Model

abstract:
  I show that the electric dipole moment of the W-boson vanishes to two loop
order in the Standard KM model. As a consequence, the electric dipole moment of
the electron vanishes to three loop order. Including QCD corrections may give a
non-vanishing result; I estimate d_W \approx 8 10^-31 ecm which induces an
electron EDM \approx 8 10^-41 ecm, considerably smaller found in a previous
calculation.


title: A More-Effective Potential

abstract:
  In theories with spontaneous symmetry breaking, the loop expansion of the
effective potential is awkward. In such theories, the exact effective potential
$V(\phi_c,T)$ is real and convex (as a function of the classical field
$\phi_c$), but its perturbative series can be complex with a real part that is
concave. These flaws limit the utility of the effective potential, particularly
in studies of the early universe. A generalization of the effective potential
is available that is real, that has no obvious convexity problems, and that can
be computed in perturbation theory. For the theory with classical potential
$V(\phi) = (\lambda/4)(\phi^2 - \sigma^2)^2$, this more-effective potential
closely tracks the usual effective potential where the latter is real $|\phi_c|
\geq \sigma/\sqrt{3}$ and naturally extends it to $\phi_c = 0$, revealing that
the critical temperature at the one-loop level runs from $T_C \approx 1.81
\sigma$ for $\lambda = 0.1$ to $T_C \approx 1.74 \sigma$ for $\lambda = 1$.


title:
Chiral Dynamics and Heavy-Fermion Formalism in Nuclei: I. Exchange Axial
  Currents

abstract:
  Chiral perturbation theory in heavy-fermion formalism is developed for
meson-exchange currents in nuclei and applied to nuclear axial- charge
transitions. Calculation is performed to the next-to-leading order in chiral
expansion which involves graphs up to one loop. The result turns out to be very
simple. The previously conjectured notion of "chiral filter mechanism" in the
time component of the nuclear axial current and the space component of the
nuclear electromagnetic current is verified to that order. As a consequence,
the phenomenologically observed soft-pion dominance in the nuclear process is
given a simple interpretation in terms of chiral symmetry in nuclei. In this
paper, we focus on the axial current, relegating the EM current which can be
treated in a similar way to a separate paper. We discuss the implication of our
result on the enhanced axial-charge transitions observed in heavy nuclei and
clarify the relationship between the phenomenological meson-exchange
description and the chiral Lagrangian description.


title: Probes of parton transversity

abstract:
  An inventory is made of the experiments which can measure the transversely
polarized quark distributions and fragmentation functions at leading twist.
(Contribution to the 10th International Symposium on High Energy Spin Physics,
Nagoya, Japan, Nov. 9-14, 1992)


title: Neutrinoless double beta decay in an $SU(3)_L\otimes U(1)_N$ model

abstract:
  We consider a model for the electroweak interactions with $SU(3)_L\otimes
U(1)_N$ gauge symmetry. We show that, it is the conservation of $F=L+B$ which
forbids massive neutrinos and the neutrinoless double beta decay,
$(\beta\beta)_{0\nu}$. Explicit and spontaneous breaking of $F$ imply that the
neutrinos have an arbitrary mass and $(\beta\beta)_{0\nu}$ proceeds also with
some contributions that do not depend explicitly on the neutrino mass.


title: Supersymmetric Higgs Bosons at the Limit

abstract:
  We obtain an improved upper bound on the lightest neutral CP-even Higgs boson
mass from a low energy renormalisation-group analysis of the Higgs sector of
the next-to-minimal supersymmetric standard model. We find $m_h< 145$ GeV for
$m_t=90$ GeV, decreasing to $m_h< 123$ GeV for $m_t=180$ GeV. We also discuss
the light Higgs spectrum in the region of parameter space close to the upper
bound.


title: Photon-Photon Scattering, Pion Polarizability and Chiral Symmetry

abstract:
  Recent attempts to detect the pion polarizability via analysis of
$\gamma\gamma\rightarrow\pi\pi$ measurements are examined. The connection
between calculations based on dispersion relations and on chiral perturbation
theory is established by matching the low energy chiral amplitude with that
given by a full dispersive treatment. Using the values for the polarizability
required by chiral symmetry, predicted and experimental cross sections are
shown to be in agreement.


title: Physics at B-Factories

abstract:
  The main motivation for B factories is the investigation of CP violation. We
consider two questions: 1) Why has there been essentially no experimental
progress in CP violation in the 28 years since its discovery in 1964? 2) Why do
we expect better results from B factories?


title: The Electroweak Phase Transition in Minimal Supergravity Models

abstract:
  We have explored the electroweak phase transition in minimal supergravity
models by extending previous analysis of the one-loop Higgs potential to
include finite temperature effects. Minimal supergravity is characterized by
two higgs doublets at the electroweak scale, gauge coupling unification, and
universal soft-SUSY breaking at the unification scale. We have searched for the
allowed parameter space that avoids washout of baryon number via unsuppressed
anomalous Electroweak sphaleron processes after the phase transition. This
requirement imposes strong constraints on the Higgs sector. With respect to
weak scale baryogenesis, we find that the generic MSSM is {\it not}
phenomenologically acceptable, and show that the additional experimental and
consistency constraints of minimal supergravity restricts the mass of the
lightest CP-even Higgs even further to $m_h\lsim 32\GeV$ (at one loop), also in
conflict with experiment. Thus, if supergravity is to allow for baryogenesis
via any other mechanism above the weak scale, it {\it must} also provide for
B-L production (or some other `accidentally' conserved quantity) above the
electroweak scale. Finally, we suggest that the no-scale flipped $SU(5)$
supergravity model can naturally and economically provide a source of B-L
violation and realistically account for the observed ratio $n_B/n_\gamma\sim
10^{-10}$.


title:
Searching for T,CP,CPT,and \Delta S = \Delta Q rule violations in the
  neutral K meson system - a guide

abstract:
  It is known that the existing experimental limit for$ CPT $ violation is
rather poor; the 10 \% level at best. The $ \DSDQ $ rule is tested only up to 2
\%. In this note, we discuss the possibility of measuring $ T, CP, CPT $ and $
\DSDQ $ rule violations in the neutral $ K $ meson system. It is shown that not
all the symmetry breaking parameters can be determined at a symmetric $ \phi $
factory. Experiments with $ K^0 $ and $ \bar{K}^0 $ beams are needed to test
all the symmetries.


title:
Spontaneous CP Violation in the Minimal Supersymmetric Standard Model at
  Finite Temperature

abstract:
  We show that in the Minimal Supersymmetric Standard Model one--loop effects
at finite temperature may lead to a spontaneous breaking of CP invariance in
the scalar sector. Requiring that the breaking takes place at the critical
temperature for the electroweak phase transition, we find that the parameters
space is compatible with a mass of the Higgs pseudoscalar in agreement with the
present experimental lower bounds. Possible implications for baryogenesis are
discussed.


title: The three-loop QCD $\beta$-function and anomalous dimensions

abstract:
  The analytic calculation of the three-loop QCD $\beta$-function and anomalous
dimensions within the minimal subtraction scheme in an arbitrary covariant
guage is presented. The result for the $\beta$-function coincides with the
previous calculation \cite{tvz}.


title: Long Distance Contributions to B-Decays into Higher K-Resonances

abstract:
  We use the new symmetries in the heavy quark limit to calculate the exclusive
B-decays $B \rightarrow K^i \psi $ where $K^i$ are higher resonances of
K-meson. We then estimate the long distance contributions to $B \rightarrow K^i
\gamma $ decays via $\psi - \gamma$ conversion. The results point to around $30
\%$ uncertainty in the top quark mass determined by measurements of rare
B-decays $B \rightarrow K^i \gamma$.


title: Progress in Electroweak Baryogenesis

abstract:
  Recent work on generating the excess of matter over antimatter in the early
universe during the electroweak phase transition is reviewed.


title: Small-Size Instanton Corrections to the $\tau$ Hadronic Width

abstract:
  We compute the effect of small-size instanton corrections to current-current
correlators, for all combinations of axial, vector, and possibly flavour
non-diagonal currents. We apply our result to the hadronic decays of the $\tau$
lepton, in order to assess the reliability of the determination of $\as$ from
the $\tau$ hadronic width.


title:
Cosmological Consequences of Spontaneous Lepton Number Violation in
  $SO(10)$ Grand Unification, EFI-93-07

abstract:
  Cosmological constraints on grand unified theories with spontaneous lepton
number violation are analysed. We concentrate on $SO(10)$, the simplest of the
models possessing this property. It has been noted previously that the
consistency of these models with the observed baryon asymmetry generically
implies strict upper bounds on the light neutrino masses. In this paper, we
analyze the situation in detail. We find that minimal models of fermion masses
face difficulties, but that it is possible for these models to generate an
adequate baryon asymmetry via non-equilibrium lepton number violating processes
when the right-handed neutrino masses are near their maximum possible values.
This condition uniquely picks out the minimal gauge symmetry breaking scheme. A
non-minimal model is also analyzed, with somewhat different conclusions due to
the nature of the imposed symmetries.


title:
Neutrino Energy Loss from the Plasma Process at all Temperatures and
  Densities

abstract:
  We present a unified approach which is accurate at all temperatures and
densities for calculating the energy loss from a stellar plasma due to the
plasma process, the decay of photons and plasmons into neutrino pairs. To allow
efficient numerical calculations, an analytic approximation to the dispersion
equations for photons and plasmons is developed. It is correct to order
$\alpha$ in the classical, degenerate, and relativistic limits for all momenta
$k$ and is correct at small $k$ for all temperatures and electron densities.
Within the same approximations, concise expressions are derived for the
transverse, longitudinal, and axial vector components of the neutrino
emissivity.


title:
E2/M1 Mixing Ratio of $\Delta\to N\gamma$ and Hyperon Resonance
  Radiative Decay

abstract:
  We compute the leading contribution to the E2/M1 mixing ratio of the decay
$\Delta\rightarrow N\gamma$ in heavy baryon chiral perturbation theory. We find
the mixing ratio to be $4\% \ltap |\delta_{\rm E2/M1}| \ltap 11\%$, much larger
than estimates based on the quark model and other hadronic models. We also
compute the mixing ratio for the radiative decay of the hyperon resonances. The
decays $\Sigma^{*+}\rightarrow\Sigma^+\gamma$ and
$\Xi^{*-}\rightarrow\Xi^-\gamma$ provide a particularly sensitive probe of
deviations from heavy baryon spin-flavour SU(6).


title: The Breaking of the SU(3)^3 Gauge Group

abstract:
  We discuss why the SU(3)^3 supersymmetric model with the most general
superpotential can naturally break to the standard model if gauge singlets and
a discrete symmetry are included. This mechanism does away with the need for
fine-tuning in the form of the assumed absence of certain terms in the
superpotential. It also automatically guarantees that any abelian discrete
phase symmetry of the GUT will survive the symmetry breaking. Such a discrete
symmetry, also known as the matter parity, is needed to suppress both proton
decay and the flavor changing neutral current (FCNC), and may help solve the
hierarchy problem.


title:
Production of two hard isolated photons in
  $e^+e^-\to\mu^+\mu^-\gamma\gamma$ at LEP

abstract:
  A calculation of the hard bremsstrahlung process e+ e- -> mu+ mu- gamma gamma
is presented and compared with recent results from the L3 Collaboration.


title: Violations of Dashen's Theorem

abstract:
  The electromagnetic contribution to the $K^+ - K^0$ mass difference is
calculated in the $1/N_c$ approach including the $SU(3)$ breaking contributions
due to a non-zero strange quark mass. The short-distance contribution can be
unambiguously determined in terms of the known parameters of the
next-to-leading order chiral lagrangian. The long distance part is estimated
using the $1/N_c$ approach by Bardeen et al. Relatively large corrections are
found.