title: Signals For Parity Violation in the Electroweak Symmetry Breaking Sector

abstract:
  We consider the possibility of observing a parity violating but $CP$
conserving interaction in the symmetry breaking sector of the electroweak
theory. We find that the best probe for such an interaction is a
forward-backward asymmetry in $W^+W^-$ production from polarized $e^-_R e^+_L$
collisions. An observable asymmetry would be strong evidence against a
custodial $SU(2)$ symmetry. We also discuss the effects of such an interaction
in future $e^- \gamma$ colliders as well as in rare decays of $K$ and $B$
mesons.


title: Cancellation of Infrared Divergences in Thermal QED

abstract:
  As a preliminary step, the radiation produced by a classical charged current
coupled to a quantized $A_{\mu}$ is solved. To each order in $\alpha$, all
infrared divergences cancel between the virtual $\gamma$'s and the real
$\gamma$'s absorbed from the plasma or emitted into the plasma. When all orders
of perturbation theory are summed, the finite answer predicts a suppression of
radiation with $\omega< \alpha T$. The analysis of QED then consists of two
steps. First, a general probability at $T\neq 0$ is organized so that all the
virtual $e^{\pm},\gamma$ are in the amplitudes and all the real
$e^{\pm},\gamma$ are in the phase space integrations. Next, the cancellations
of IR divergences between virtual and real are demonstrated.


title: Dynamical Electroweak Breaking: Issues and Challenges

abstract:
  After briefly remarking on alternatives for breaking the electroweak
symmetry, I discuss the implication that recent precision experiments at LEP
have for the symmetry breaking sector. The difficulties associated with
generating fermion masses when the electroweak symmetry is broken dynamically
are exposed and an alternative to the walking technicolor - extended
technicolor scenario is suggested, based on models of substructure. Failures
and lessons from trying to incorporate families and mixing in these latter
schemes are also discussed.


title:
Testing the handedness of a heavy $W^{\prime}$ at future hadron
  colliders

abstract:
  We show that the associated production $pp\to W^{\prime}W$, and the rare
decay $pp\to W'\to \bar\ell\ell W$ are useful tests of $W'$ couplings to
fermions at future hadron colliders. For $M_{W'}\sim (1 - 3)$ TeV they would
allow a clean determination on whether the $W'$ couples to $V-A$ or $V+A$
currents. As an illustration a model in which the $W^{\prime\pm}$ couples only
to $V-A$ currents is contrasted to the left-right symmetric models which
involve $V+A$ currents.


title: The Updated MSW Analysis and the Standard Solar Model Uncertainties

abstract:
  We update the analysis of the MSW and general astrophysical solutions to the
combined solar neutrino observations by including the GALLEX II result. We also
show that our parametrized flux uncertainties are equivalent to the Monte-Carlo
results of Bahcall and Ulrich.


title:
On the relation between Euclidean and real time calculations of Green
  functions at finite temperature

abstract:
  We find a relation between the semiclassical approximation of the temperature
(Matsubara) 2-point correlator and the corresponding classical Green function
in real time at finite temperature. The anharmonic oscillator at finite
temperature is used to illustrate our statement, which is however of rather
general origin.


title: On the Hadronic Contribution to Light-by-light Scattering in $g_\mu-2$

abstract:
  We comment on the theoretical uncertainties involved in estimating the
hadronic effects on the light-by-light scattering contribution to the anomalous
magnetic moment of the muon, especially based on the analysis and results of T.
Kinoshita, B. Ni\v zi\'c, and Y. Okamoto, Phys.\ Rev.\ D31, 2108 (1985). From
the point of view of an effective field theory and chiral perturbation theory,
we suggest that the charged pion contribution may be better determined than has
been appreciated. However, the neutral pion contribution needs greater
theoretical insight before its magnitude can be reliably estimated.


title:
Do Search for Dibaryonic De - Excitations in Relativistic Nuclear
  Reactions

abstract:
  Some odd characteristics are observed in the single particle distributions
obtained from $ He + Li $ interactions at $ 4.5 AGeV/c $ momenta which are
explained as the manifestation of a new mechanism of strangeness production via
dibaryonic de-excitations. A signature of the formation of hadronic and
baryonic clusters is also reported. The di-pionic signals of the dibaryonic
orbital de-excitations are analyzed in the frame of the MIT - bag Model and a
Monte Carlo simulation.The role played by the dibaryonic resonances in
relativistic nuclear collisions could be a significant one.
  Key words: Relativistic nuclear interactions negative pions, negative kaons,
di-pions , streamer chamber, dibaryons, MIT - bag model
  PACS codes: 25.75.+r,14.40.Aq,14.20.Pt,12.40.As


title:
Study of the simplest realistic Higgs sector in quark-lepton symmetric
  models

abstract:
  A discrete symmetry between quarks and (generalized) leptons can exist in
nature, and its spontaneous symmetry breaking scale can be as low as a few TeV.
Such a discrete symmetry also has interesting implications for how electroweak
symmetry is spontaneously broken, because the simplest version of the theory
requires two electroweak Higgs doublets rather than one in order to provide
acceptable values for quark and lepton masses. The effective theory generated
at electroweak-scale energies is thus a particular type of two-Higgs-doublet
model. We point out in this paper that the broken discrete symmetry imposes
very interesting constraints on the form of the Yukawa couplings between
physical Higgs bosons and quarks and leptons. In particular, we find that the
flavour-changing neutral Higgs couplings to down-sector quarks are proportional
to the neutrino Dirac mass matrix. If neutrinos are Dirac particles, then the
severe experimental upper bounds on their mass values renders tree-level
neutral flavour-changing Higgs effects on down-quark systems like
$K^0-\bar{K}^0$ negligibly small. We also discuss minimization of some relevant
Higgs potentials and some other pertinent phenomenological issues.


title: Parton Interaction Rates in the Quark-Gluon Plasma

abstract:
  The transport interaction rates of elastic scattering processes of thermal
partons in the quark-gluon plasma are calculated beyond the leading logarithm
approximation using the effective perturbation theory for QCD at finite
temperatures developed by Braaten and Pisarski. The results for the ordinary
and transport interaction rates obtained from the effective perturbation theory
are compared to perturbative approximations based on an infrared cut-off by the
Debye screening mass. The relevance of those interaction rates for a
quark-gluon plasma possibly formed in ultrarelativistic heavy ion collisions
are discussed.


title: Astrophysical and Terrestrial Constraints on Singlet Majoron Models

abstract:
  The general Lagrangian containing the couplings of the Higgs scalars to
Majorana neutrinos is presented in the context of singlet Majoron models with
intergenerational mixings. The analytical expressions for the coupling of the
Majoron field to fermions are derived within these models. Astrophysical
considerations imply severe restrictions on the parameters of the model if the
singlet Majoron model with three generations is assumed to be embedded in grand
unified theories. Bounds that originate from analyzing possible charged
lepton-violating decays in terrestrial experiments are also discussed. In
particular, we find that experimental searches for muon decays by Majoron
emission cannot generally be precluded by astrophysical requirements.


title:
Gauge-Symmetric Approach to Effective Lagrangians: The \eta' Meson from
  QCD

abstract:
  We present a general scheme for extracting effective degrees of freedom from
an underlying fundamental Lagrangian, through a series of well-defined
transformations in the functional integral of the cut-off theory. This is done
by introducing collective fields in a gauge-symmetric manner. Through
appropriate gauge fixings of this symmetry one can remove long-distance degrees
of freedom from the underlying theory, replacing them by the collective fields.
Applying this technique to QCD, we set out to extract the long-distance
dynamics in the pseudoscalar flavour singlet sector through a gauging (and
subsequent gauge fixing) of the $U(1)_A$ flavour symmetry which is broken by
the anomaly. By this series of exact transformations of a cut-off generating
functional for QCD, we arrive at a theory describing the long-distance physics
of a pseudoscalar flavour singlet meson coupled to the residual quark-gluon
degrees of freedom. As examples of how known low-energy physics can be
reproduced in this formulation, we rederive the Witten-Veneziano relation
between the $\eta'$ mass and the topological susceptibility, now for any value
of the number of colours $N_c$.


title: Flow Equations for N Point Functions and Bound States

abstract:
  We discuss the exact renormalization group or flow equation for the effective
action and its decomposition into one particle irreducible N point functions.
With the help of a truncated flow equation for the four point function we study
the bound state problem for scalar fields. A combination of analytic and
numerical methods is proposed, which is applied to the Wick-Cutkosky model and
a QCD-motivated interaction. We present results for the bound state masses and
the Bethe-Salpeter wave function. (Figs. 1-4 attached as separate uuencoded
post-script files.)


title: QCD calculation of J/psi+gamma mass distributions

abstract:
  We compute the J/psi+gamma invariant-mass distributions from the QCD
subprocess g + g --> J/psi+gamma. At large masses, this subprocess is the
dominant mechanism for J/psi+gamma production, and data could provide a good
test of QCD. The mass distribution peaks at relatively small masses (3.4 - 4.0
GeV) and the subprocess could, therefore, represent a significant QCD
background to J/psi+gamma decay of heavier charmonia. We also analyze the J/psi
angular distribution in the J/psi+gamma rest frame.


title:
Operator Product Expansion for Inclusive Semileptonic Decays in Heavy
  Quark Effective Field Theory

abstract:
  Inclusive semileptonic decays are discussed in the framework of heavy quark
effective field theory by employing the short distance expansion in the
effective theory. The lowest order term turns out to be the parton model; the
higher order terms may be regarded as correction terms to the parton model
result. The first nonvanishing corrections to the parton model result are given
and the lepton energy spectrum of inclusive semileptonic decays of heavy mesons
is calculated.


title: Q^2-Dependence of the Proton's G_1 Structure Function Sum Rule

abstract:
  We study the $Q^2$ variation of the first moment of the nucleon's
spin-dependent structure function $G_1$. As $Q^2 \rightarrow 0$ the moment is
determined by the low energy theorem for Compton scattering. In the
deep-inelastic region the moment is calculated using twist expansion to order
$1/Q^2$. Based on these limits, we construct a formula which smoothly
interpolates between the two regions.


title: Radiative $B \to K^* \gamma $ transition in QCD

abstract:
  We evaluate the branching ratios of the radiative decays $B \to K^* \gamma $,
and $B \to K_1 \gamma $ in the framework of three-point function QCD sum rules.
We find: $ \Gamma(B \to K^* \gamma) / \Gamma(b \to s \gamma) = 0.17 \pm 0.05$
and $ \Gamma(B \to K_1 \gamma) / \Gamma(b \to s \gamma) = 0.30 \pm 0.15$. We
also study, in the infinite quark mass limit, the connection between the form
factor of the radiative $B \to K^* \gamma $ transition and the weak hadronic
form factors entering the semileptonic B-meson decays.


title: The Exact Renormalisation Group and Approximate Solutions

abstract:
  We investigate the structure of Polchinski's formulation of the flow
equations for the continuum Wilson effective action.
  Reinterpretations in terms of I.R. cutoff greens functions are given. A
promising non-perturbative approximation scheme is derived by carefully taking
the sharp cutoff limit and expanding in `irrelevancy' of operators.
  We illustrate with two simple models of four dimensional $\lambda \varphi^4$
theory: the cactus approximation, and a model incorporating the first
irrelevant correction to the renormalized coupling. The qualitative and
quantitative behaviour give confidence in a fuller use of this method for
obtaining accurate results.


title: The strongest experimental constraints on SU(5)xU(1) supergravity models

abstract:
  We consider a class of well motivated string-inspired flipped $SU(5)$
supergravity models which include four supersymmetry breaking scenarios:
no-scale, strict no-scale, dilaton, and special dilaton, such that only three
parameters are needed to describe all new phenomena $(m_t,\tan\beta,m_{\tilde
g})$. We show that the LEP precise measurements of the electroweak parameters
in the form of the $\epsilon_1$ variable, and the CLEOII allowed range for
$\bsg$ are at present the most important experimental constraints on this class
of models. For $m_t\gsim155\,(165)\GeV$, the $\epsilon_1$ constraint (at
90(95)\%CL) requires the presence of light charginos
($m_{\chi^\pm_1}\lsim50-100\GeV$ depending on $m_t$). Since all sparticle
masses are proportional to $m_{\tilde g}$, $m_{\chi^\pm_1}\lsim100\GeV$
implies: $m_{\chi^0_1}\lsim55\GeV$, $m_{\chi^0_2}\lsim100\GeV$, $m_{\tilde
g}\lsim360\GeV$, $m_{\tilde q}\lsim350\,(365)\GeV$, $m_{\tilde
e_R}\lsim80\,(125)\GeV$, $m_{\tilde e_L}\lsim120\,(155)\GeV$, and
$m_{\tilde\nu}\lsim100\,(140)\GeV$ in the no-scale (dilaton) flipped $SU(5)$
supergravity model. The $\bsg$ constraint excludes a significant fraction of
the otherwise allowed region in the $(m_{\chi^\pm_1},\tan\beta)$ plane
(irrespective of the magnitude of the chargino mass), while future experimental
improvements will result in decisive tests of these models. In light of the
$\epsilon_1$ constraint, we conclude that the outlook for chargino and
selectron detection at LEPII and at HERA is quite favorable in this class of
models.


title: Moments of the Virtual Photon Structure Function

abstract:
  The photon structure function is a useful testing ground for QCD. It is
perturbatively computable apart from a contribution from what is usually called
the hadronic component of the photon. There have been many proposals for this
nonperturbative part of the real photon structure function. By studying moments
of the virtual photon structure function, we explore the extent to which these
proposed nonperturbative contributions can be identified experimentally.


title:
Investigation of Long Baseline Neutrino Oscillations from Experiments at
  KAON

abstract:
  The proposed KAON factory at the Triumf Laboratory in Vancouver, Canada
provides a unique opportunity for high statistics long baseline neutrino
oscillation experiments. Several possibilities are under active consideration.
In this paper we describe the theoretical expectations for a {\it very} long
baseline experiment in which the neutrinos are directed towards, and detected
at the Superkamiokande detector in Kamioka, Japan 7200 km away. We find that in
the first year this experiment would probe oscillations down to about $\Delta
m^2_0 = 9 \times 10^{-5} eV^2$ for maximal mixing, and if $\Delta m^2_0 \geq 5
\times 10^{-4} eV^2$ it would be sensitive to $sin^2(2 \theta_0) \geq 0.2$.
These results are compared with a more modest proposal of a 100 km baseline
with a 6300 tonne detector which would probe $\Delta m^2_0 \geq 1.3 \times
10^{-3} eV^2$ for maximal mixing, and if $\Delta m^2_0 \geq 0.02 eV^2$ it would
be sensitive to $sin^2(2 \theta_0) \geq 0.01$. These experiments would either
confirm or rule out the entire range of parameters allowed by Kamiokande and
IMB to explain the deficit in the ratio of $\nu_\mu$ to $\nu_e$ in current
atmospheric neutrino experiments. The Kamiokande experiment would also
investigate matter enhanced neutrino oscillations (the MSW effect) down to
about $\Delta m^2 = 3 \times 10^{-4} eV^2$.


title: Cosmic Ray Signatures of Multi-W Processes

abstract:
  We explore the discovery potential of cosmic ray physics experiments for
Standard Model processes involving the nonperturbative production of O(30) weak
gauge bosons. We demonstrate an experimental insensitivity to proton-induced
processes and emphasize the importance of neutrino-induced processes. The Fly's
Eye currently constrains the largest region of parameter space characterizing
multi-W phenomena if a cosmic neutrino flux exists at levels suggested by
recent models of active galactic nuclei. MACRO (DUMAND) can constrain or
observe additional regions by searching for 1-100 (1-10) characteristic
near-vertical (near-horizontal) spatially compact energetic muon bundles per
year.


title: On Primordial Magnetic Fields of Electroweak Origin

abstract:
  We consider Vachaspati's primordial magnetic field which is generated at the
electroweak phase transition. Assuming that either the gradients of the Higgs
field or, alternatively, the magnetic field itself are stochastic variables
with a normal distribution, we find that the resulting magnetic field has an
{\em rms} value in the present-day universe which is fully consistent with what
is required for the galactic dynamo mechanism.


title: Towards a Theory of Soft Terms for the Supersymmetric Standard Model

abstract:
  We perform a systematic analysis of the soft supersymmetry-breaking terms
arising from four-dimensional strings. The analysis does not assume any
specific supersymmetry-breaking mechanism but provides a means of parametrizing
our ignorance in a way consistent with some known properties of
four-dimensional strings. We introduce a {\it goldstino angle} parameter
$\theta $ which says where the source of supersymmetry-breaking resides, either
predominantly in the dilaton sector ($sin \theta =1$ limit) or in the rest of
the chiral fieds, notably the moduli ($sin\theta =0$ limit). All formulae for
soft parameters take particularly simple forms when written in terms of this
angle. The $sin\theta =1$ limit is (up to small corrections) universal. As
$sin\theta $ decreases, the model dependence increases and the resulting soft
terms may or may not be universal, depending on the model. General expressions
for the soft terms as functions of $\theta$ for generic four-dimensional
strings are provided. For each {\it given} string model, one trades the four
soft parameters ($M,m,A,B$) of the minimal supersymmetric standard model by the
two parameters $m_{3/2}$ (gravitino mass) and $sin\theta $. The role of complex
phases and the associated constraints from limits on the electric dipole moment
of the neutron are discussed. It is also emphasized the importance of treating
the problem of the cosmological constant in a self-consistent manner.


title:
The Rare Decays $K^+\to\pi^+\nu\bar\nu$\ and $K_L\to\mu^+\mu^-$\ Beyond
  Leading Logarithms

abstract:
  We analyze the branching ratio for the FCNC mode $K^+\to\pi^+\nu\bar\nu$\ in
the standard model with QCD effects taken into account consistently to
next-to-leading order. This involves a two-loop renormalization group analysis
for the charm contribution, presented in this paper, and the calculation of
$O(\alpha_s)$ corrections to all orders in $m_t/M_W$ for the top-quark case
that we have described elsewhere. The inclusion of next-to-leading corrections
reduces considerably the theoretical uncertainty due to the choice of the
renormalization scales, inherent in any calculation to finite order in
perturbation theory. For $K^+\to\pi^+\nu\bar\nu$\ this point has not been
discussed previously. In particular, the related uncertainty in the
determination of $|V_{td}|$ from $B(K^+\to\pi^+\nu\bar\nu)$ is reduced from
$\sim 30\%$ to $\sim 7\%$ for typical values of the parameters. Simultaneously
also the dependence of $B(K^+\to\pi^+\nu\bar\nu)$ on the choice of $m_c$ is
considerably reduced. We also give the next-to-leading order expression for the
short-distance part of $K_L\to\mu^+\mu^-$. Impacts of our calculations on the
determination of the unitarity triangle are presented.


title: One-Loop Corrections to Bubble Nucleation Rate at Finite Temperature

abstract:
  We present an evaluation of the 1-loop prefactor in the lifetime of a
metastable state which decays at finite temperature by bubble nucleation. Such
a state is considered in one-component phi^4 model in three space dimensions.
The calculation serves as a prototype application of a fast numerical method
for evaluating the functional determinants that appear in semiclassical
approximations.


title:
Connections between Deep-Inelastic and Annihilation Processes at
  Next-to-Next-to-Leading Order and Beyond

abstract:
  We have discovered 7 intimate connections between the published results for
the radiative corrections, $\Ck$, to the Gross--Llewellyn Smith (GLS) sum rule,
in deep-inelastic lepton scattering, and the radiative corrections, $\Cr$, to
the Adler function of the flavour-singlet vector current, in $\ee$
annihilation. These include a surprising relation between the
scheme-independent single-electron-loop contributions to the 4-loop QED
$\beta$\/-function and the zero-fermion-loop abelian terms in the 3-loop GLS
sum rule. The combined effect of all 7 relations is to give the factorization
of the 2-loop $\beta$\/-function in
\[\Ds\equiv\Ck\Cr-1=\frac{\Be}{\Aq}\left\{S_1\Cf\Aq+\left[S_2\Tf\Nf
+\Sa\Ca+\Sf\Cf\right]\Cf\Aq^2\right\}+O(\Aq^4)\,,\] where
$\Aq=\al(\mu^2=Q^2)/4\pi$ is the $\MS$ coupling of an arbitrary colour gauge
theory, and \[S_1=-\Df{21}{2}+12\Ze3\,;\quad
S_2=\Df{326}{3}-\Df{304}{3}\Ze3\,;\quad
\Sa=-\Df{629}{2}+\Df{884}{3}\Ze3\,;\quad \Sf=\Df{397}{6}+136\Ze3-240\Ze5\]
specify the sole content of $\Ck$ that is not already encoded in $\Cr$ and
$\Be=Q^2\rd\Aq/\rd Q^2$ at $O(\Aq^3)$. The same result is obtained by combining
the radiative corrections to Bjorken's polarized sum rule with those for the
Adler function of the non-singlet axial current. We suggest possible origins of
$\beta$ in the `Crewther discrepancy', $\Ds$, and determine $\Ds/(\Be/\Aq)$, to
all orders in $\Nf\Aq$, in the large-$\Nf$ limit, obtaining the {\em entire\/}
series of coefficients of which $S_1$ and $S_2$ are merely the first two
members.


title: Cubic Mass Relation in $\rm SU(3)\times U(1)$ Electroweak Theory

abstract:
  In the 331 model, lepton number may be explicitly broken by trilinear scalar
self couplings. This leads to neutrino masses proportional to the cube of the
corresponding charged lepton mass, with consequences for solar neutrinos and
for hot dark matter.


title:
The Electroweak Chiral Lagrangian for the Standard Model with a Heavy
  Higgs

abstract:
  The most general chiral Lagrangian for electroweak interactions with the
complete set of $SU(2)_L\times U(1)_Y$ invariant operators up to dimension four
is considered. The two-point and three-point functions with external gauge
fields are derived from this effective chiral Lagrangian to one-loop order in a
generic $R_\xi$-gauge. The same set of Green's functions are paralelly studied
in the renormalizable standard model to one-loop order, in a $R_\xi$-gauge and
in the large Higgs mass limit. An appropriate set of matching conditions
connecting the Green's functions of the two theories allows us to derive,
systematically, the values of the chiral Lagrangian coefficients corresponding
to the large Higgs mass limit of the standard model. These chiral parameters
represent the non-decoupling effects of a heavy Higgs particle and incorporate
both the leading logarithmic dependence on $\mh$ and the next to leading
constant contributions. Some phenomenological implications are also discussed.


title: Naturally Large Tan $\beta$

abstract:
  We show that if there are only two Higgs doublets in the supersymmetric
standard model, large $\tan\beta$ requires a fine tuning in the parameters of
the Lagrangian of order ($1/\tan\beta$), which cannot be explained by any
approximate symmetry. With an extended Higgs sector, large $\tan\beta$ can be
natural. We give an explicit example with four doublets in which it is possible
to achieve large $\tan\beta$ as a result of an approximate symmetry, without
any light superpartners. The approximate symmetry can be extended to explain
all the hierarchies in the quark mass matrix.


title: Zeros of tree amplitudes at rest and symmetries of mechanical systems

abstract:
  We consider the tree amplitudes of production of $n_2$ scalar particles by
$n_1$ particles of another kind, where both initial and final particles are at
rest and on mass shell, in a model of two scalar fields with $O(2)$ symmetric
interaction and unequal masses. We find that these amplitudes are zero except
for the lowest possible $n_1$ and $n_2$, and that the cancellation of the
corresponding Feynman graphs occurs due to a special symmetry of the classical
mechanical counterpart of this theory. This feature is rather general and is
inherent in various other scalar field theories.


title: Pseudo-Stable Bubbles

abstract:
  The evolution of spherically symmetric unstable scalar field configurations
(``bubbles'') is examined for both symmetric (SDWP) and asymmetric (ADWP)
double-well potentials. Bubbles with initial static energies $E_0\la E_{{\rm
crit}}$, where $E_{{\rm crit}}$ is some critical value, shrink in a time scale
determined by their linear dimension, or ``radius''. Bubbles with $E_0\ga
E_{{\rm crit}}$ evolve into time-dependent, localized configurations which are
{\it very} long-lived compared to characteristic time-scales in the models
examined. The stability of these configurations is investigated and possible
applications are briefly discussed.tic time-scales in the models examined. The
stability of these configurations is investigated and possible applications are
briefly discussed.


title: Nucleation Rates in Flat and Curved Space

abstract:
  Nucleation rates for tunneling processes in Minkowski and de Sitter space are
investigated, taking into account one loop prefactors. In particular, we con-
sider the creation of membranes by an antisymmetric tensor field, analogous to
Schwinger pair production. This can be viewed as a model for the decay of false
(or true) vacuum at zero temperature, in the thin wall limit. Also considered
is the spontaneous nucleation of strings, domain walls and monopoles during
inflation. The instantons for these processes are spherical world-sheets or
world-lines embedded in flat or de Sitter backgrounds. We find the contribution
of such instantons to the semiclassical partition function, including one loop
corrections due to small fluctuations around the spherical worldsheet. We sug-
gest a prescription for obtaining the distribution of objects nucleated during
inflation. This can be seen as an extension of the usual formula, valid in flat
space, according to which the nucleation rate is twice the imaginary part of
the free energy. In addition, we use the method of Bogolubov transformations to
compute the rate of pair production by an electric field in 1+1 dimensional de
Sitter space, and compare the results to those obtained using the instanton me-
thod. Both results agree where they are expected to, not only in the exponen-
tial dependence but also in the prefactor, confirming the validity of instanton
techniques in de Sitter space. Throughout the paper, both the gravitational
field and the antisymmetric tensor field are assumed external.


title: Single Top Production in $e\gamma$ Collisions

abstract:
  We study single top production in high energy $e\gamma$ collisions. The
process $e\gamma\to\nu b\bar t$ can serve as a unique tool for measuring the
$Wtb$ coupling. We show that allowing for realistic luminosity and backgrounds,
the size of this coupling can be determined to within 10 (5)\% in an $e\gamma$
collider built around a 500 (1000) GeV $e^+e^-$ collider.


title:
Does $K_L-K_S$ mass difference constraints or \\ claims new physics
  beyond the Standard Model?

abstract:
  The ratio $\Delta m_K/m_K$ within the standard model with 3 generations is
calculated as a function of the CP nonconserving phase $\delta_{13}$ and the
quark masses $m_c,m_t$ assuming the current values of the
Cabibbo-Kobayashi-Maskawa mixing angles. We have found that varying
$\delta_{13}$ and $m_c$ within the allowed range, not all the values for the
top quark mass fit the experimental value for that ratio.


title: Corrections to Chiral Dynamics of Heavy Hadrons: (I) 1/M Correction

abstract:
  In earlier publications we have analyzed the strong and radiative decays of
heavy hadrons in a formalism which incorporates both heavy-quark and chiral
symmetries. In particular, we have derived a heavy-hadron chiral Lagrangian
whose coupling constants are related by the heavy-quark flavor-spin symmetry
arising from the QCD Lagrangian with infinitely massive quarks. In this paper,
we re-examine the structure of the above chiral Lagrangian by including the
effects of $1/m_Q$ corrections in the heavy quark effective theory. The
relations among the coupling constants, originally derived in the heavy-quark
limit, are modified by heavy quark symmetry breaking interactions in QCD. Some
of the implications are discussed.


title:
Rotational Corrections to Axial Currents in Semibosonized SU(3)
  Nambu--Jona-Lasinio Model

abstract:
  We examine $O(1/\Ne)$ rotational corrections to axial couplings \gt~ and \go~
in the framework of the semibosonized SU(3) Nambu--Jona-Lasinio model. A
novelty is due to the observation that the rotational (cranking) velocity and
the rotation matrix itself do not commute within semiclassical quantization
scheme. If time ordering in the quark loop is maintained new contributions,
which have no analogue in the Skyrme model, appear. They substantially improve
numerical results for the axial couplings which without the present corrections
are badly underestimated.


title: Effective lagrangian for B and D semileptonic decays

abstract:
  An effective lagrangian incorporating both chiral and heavy quark symmetries
and describing the low momentum interactions of heavy mesons and light scalar
and vector resonances is presented. Using some available data and assuming
nearest pole dominance for the form factors we can calculate, at the leading
order in chiral and heavy quark expansion, semileptonic $B$ and $D$ decays into
light mesons.


title:
Quantum solitons of the nonlinear sigma-model with broken chiral
  symmetry

abstract:
  It is proved that the quantum-mechanical consideration of global breathing of
a hedgehog-like field configuration leads to the dynamically stable soliton
solutions in the nonlinear sigma-model without the Skyrme term. Such solutions
exist only when chiral symmetry of the model is broken.


title: Extracting $|V_{bc}|$, $m_c$ and $m_b$ from Inclusive $D$ and $B$ Decays

abstract:
  Using recent results for nonperturbative contributions to the $B$ and $D$
meson inclusive semileptonic widths, a model independent extraction of $\vbc$,
$m_c$ and $m_b$ is made from the experimentally measured $B$ and $D$ lifetimes
and semileptonic branching ratios. Constraining the parameters of the HQET at
$\CO(1/m_Q^2)$ by the $D$ semileptonic width, $\vbc$ is found to lie in the
range $.040<\vbc< 0.057$. The $c$ and $b$ quark masses are not well constrained
due to uncertainty in the relevant scale of $\alpha_s$. These results assume
the validity of perturbative QCD at the low scales relevant to semileptonic
charm decay. Without making this assumption, somewhat less stringent bounds on
$V_{bc}$ from $B$ decay alone may be obtained.


title:
Nonperturbative Contributions to the Inclusive Rare Decays $B\to
  X_s\gamma$ and $B\to X_s\ell^+\ell^-$

abstract:
  We discuss nonperturbative contributions to the inclusive rare $B$ decays
$B\to X_s\gamma$ and $B\to X_s\ell^+\ell^-$. We employ an operator product
expansion and the heavy quark effective theory to compute the leading
corrections to the decay rate found in the free quark decay model, which is
exact in the limit $m_b\to\infty$. These corrections are of relative order
$1/m_b^2$, and may be parameterised in terms of two low-energy parameters. We
also discuss the corrections to other observables, such as the average photon
energy in $B\to X_s\gamma$ and the lepton invariant mass spectrum in $B\to
X_s\ell^+\ell^-$.


title:
Spinor Helicity Technique and String Reorganization for Multiloop
  Diagrams

abstract:
  Methods to apply the spinor helicity technique and string reorganization to
multiloop amplitudes using the Feynman- and Schwinger-parameter representations
are reviewed and expanded.


title: The Sphaleron Barrier in the Presence of Fermions

abstract:
  We calculate the minimal energy path over the sphaleron barrier in the
pre\-sen\-ce of fermions, assuming that the fermions of a doublet are
degenerate in mass. This allows for spherically symmetric ans\"atze for the
fields, when the mixing angle dependence is neglected. While light fermions
have little influence on the barrier, the presence of heavy fermions ($M_F
\sim$ TeV) strongly deforms the barrier, giving rise to additional sphalerons
for very heavy fermions ($M_F \sim$ 10 TeV). Heavy fermions form
non-topological solitons in the vacuum sector.


title: Scalar Stoponium

abstract:
  We study the decays of a scalar \stst\ bound state \sigst, where \st\ is the
lighter stop eigenstate. If \st\ has no tree--level 2--body decays, the
dominant decay modes of \sigst\ are $gg$ or, if $m_h < \mst \ll \mstt$, a pair
of light scalar Higgs bosons $h$. The best signal for \sigst\ production at
hadron colliders is probably its decay into two photons.


title: Cosmological Implications of Dynamical Supersymmetry Breaking

abstract:
  We provide a taxonomy of dynamical supersymmetry breaking theories, and
discuss the cosmological implications of the various types of models. Models in
which supersymmetry breaking is produced by chiral superfields which only have
interactions of gravitational strength (\eg\ string theory moduli) are
inconsistent with standard big bang nucleosynthesis unless the gravitino mass
is greater than $\CO(3) \times 10^4$ GeV. This problem cannot be solved by
inflation. Models in which supersymmetry is dynamically broken by
renormalizable interactions in flat space have no such cosmological problems.
Supersymmetry can be broken either in a hidden or the visible sector. However
hidden sector models suffer from several naturalness problems and have
difficulties in producing an acceptably large gluino mass.


title:
Detecting the Photon-Photon Interaction by Colliding Laser Beam
  Interferometry

abstract:
  The feasibility of detecting the photon-photon interaction using Fabry-Perot
type laser interferometers developed for gravity wave detection is
demonstrated. An ``external'' laser beam, serving as a refractive medium, is
alternatively fed into the cavities of the interferometer and made to collide
with the ``internal'' beams thereby inducing a measurable phase difference
between them.


title:
Anomalous Dimensions of High Twist Operators in QCD at $N \rightarrow 1$
  and large $Q^2

abstract:
  The anomalous dimensions of high-twist operators in deeply inelastic
scattering ($\gamma_{2n}$) are calculated in the limit when the moment variable
$N \rightarrow 1$ (or $x_B\rightarrow 0$) and at large $Q^2$ (the double
logarithmic approximation) in perturbative QCD. We find that the value of
$\gamma_{2n}(N-1)$ in this approximation behaves as ${N_c \alpha_S \over \pi
(N-1)} n^2(1 + {\delta \over 3} (n^2-1))$ where $\delta \approx 10^{-2}$. This
implies that the contributions of the high-twist operators give rise to an
earlier onset of shadowing than was estimated before. The derivation makes use
of a Pomeron exchange approximation, with the Pomerons interacting
attractively. We find that they behave as a system of fermions.


title:
Complete Next to Leading Order QCD Corrections to the Photon Structure
  Functions $F^\gamma_2(x,Q^2)$ and $F_L^\gamma(x,Q^2)$

abstract:
  We present the complete NLO QCD analysis of the photon structure functions
$F_2^\gamma(x,Q^2)$ and $F_L^\gamma(x,Q^2)$ for a real photon target. In
particular we study the heavy flavor content of the structure functions which
is due to two different production mechanisms, namely collisions of a virtual
photon with a real photon, and with a parton. We observe that the charm
contributions are noticeable for $F_2^\gamma(x,Q^2)$ as well as
$F_L^\gamma(x,Q^2)$ in the x-region studied.


title: Lepton Flavor Violation and the Tau Neutrino Mass

abstract:
  We point out that, in the left-right symmetric model of weak interaction, if
$\nu_\tau$ mass is in the keV to MeV range, there is a strong correlation
between rare decays such as $\tau \rightarrow 3 \mu, \tau \rightarrow 3 e$ and
the $\nu_\tau$ mass. In particular, we point out that a large range of
$\nu_\tau$ masses are forbidden by the cosmological constraints on
$m_{\nu_\tau}$ in combination with the present upper limits on these processes.


title: Fields in the Vicinity of a Superconducting Cosmic String

abstract:
  Superconducting cosmic strings may be viewed as wires of thickness
$1/\Lambda$ with $\Lambda=10^{16}$ TeV. We show that the weak interactions will
spread out the current to distances $r= (1/M_Z)\ln (I/M_Z)$, where $I$ is the
magnitude of the current in the string. Consequences for the scattering of
light by these strings is presented.


title: Problem of Statistical Model in Deep Inelastic Scattering Phenomenology

abstract:
  Recent Deep Inelastic data leads to an up-down quark asymmetry of the nucleon
sea. Explanations of the flavour asymmetry and the di-lepton production in
proton-nucleus collisions call for a temperature $T \approx 100$ MeV in a
statistical model. This T may be conjectured as being due to the
Fulling-Davies-Unruh effect. But it is not possible to fit the structure
function itself.


title: The Level Crossing Phenomenon with Yukawa Interactions

abstract:
  In the minimal model of electroweak interactions we carefully investigate the
spectrum of the massive euclidean \dop \ in three, four and five dimensions
($D$) in the presence of \tly \ nontrivial \exl \ fields. More specifically we
study the cases of the \inst \ ($D=4$), \sp \ ($D=3$) as well as that of the
($D=5$) \dop \ that pertains to the existence of the \gl \ $SU(2)$ \an . We
establish the \exst \ of \nl \ massive fermion \zm s in all three cases. We
give closed form expressions which relate the massive with the massless \zm s.
As a consequence the \lc \ phenomenon is shown to be manifest and generic in
the presence of Yukawa interactions.


title: Hydrodynamical Beam Jets in High Energy Hadronic Collisions

abstract:
  A study of hadronic data up to TEVATRON energies in terms of relativistic
hydrodynamics indicates an extended 1-dimensional stage of the expansion which
suggests a jet like behaviour of the fireball along the collision axis.


title: A Relativistic Constituent Quark Model

abstract:
  We investigate the predictive power of a relativistic quark model formulated
on the light-front. The nucleon electromagnetic form factors, the semileptonic
weak decays of the hyperons and the magnetic moments of both baryon octet and
decuplet are calculated and found to be in excellent agreement with experiment.


title: Possible Tests of CP-Violations in $B^\pm$ Decays

abstract:
  Some experimental tests are suggested for possible CP-violations for decays
of $B^\pm$ bosons. Especially, a detailed comparison of decays $B^+ \rightarrow
D^0 \pi^+ \pi^+ \pi^-$ and $B^- \rightarrow \overline{D^0} \pi^- \pi^- \pi^+$
will lead to tests of not only CP, but also C, and P invariances.


title: The Pomeron as Massive Gluons

abstract:
  A QCD-Pomeron composed by two non-perturbative gluons with a dynamically
generated mass, is constructed in a gauge invariant way. The gluon propagator
is infrared-finite. The model properly describes data on elastic scattering,
exclusive $\rho$ production in deep inelastic scattering (DIS) and the
$J/\Psi$-nucleon total cross-section in terms of a single gluon mass
$m_g\simeq0.37$~GeV. The total cross sections of hadrons with small radii, such
as $J/\Psi$, are very sensitive on the effective gluon mass.


title:
Two-loop renormalization of gaugino masses in general supersymmetric
  gauge models

abstract:
  We calculate the two-loop renormalization group equations for the running
gaugino masses in general SUSY gauge models, improving our previous result. We
also study its consequence to the unification of the gaugino masses in the SUSY
SU(5) model. The two-loop correction to the one-loop relation
$m_i(\mu)\propto\alpha_i(\mu)$ is found to be of the order of a few \%.


title: Relativistic Covariant Equal-Time Equation For Quark-Diquark System

abstract:
  Relativistic three-dimensional quasipotential (equal-time) equations are
considered, which describe bound states of fermion and boson of spin S=0 or
S=1. The spin structure of the interaction quasipotentials in such systems is
studied, and corresponding partial-wave equation for the simplest case is
obtained. Such equations can be used in calculations of energy spectra, decay
rates and structure functions of quark-diquark systems (nucleons and their
resonances) as well as for description of ($\pi\mu$)- atom.


title: Non-Trivial SU(N) Instantons and Exotic Skyrmions

abstract:
  The classical Yang-Mills equations are solved for arbitrary semi-simple gauge
groups in the Schwinger-Fock gauge. 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 $n=N(N^{2}-1)/6$. Explicit
configurations are given for SU(3) and SU(4) gauge groups. By means of the
Atiyah Manton procedure Skyrmion fields are constructed from the SU(N)
instantons. These Skyrmions represent exotic baryon states.


title: Sphaleron transitions in a realistic heat bath

abstract:
  We measure the diffusion rate of Chern-Simons number in the (1+1)-dimensional
Abelian Higgs model interacting with a realistic heat bath for temperatures
between 1/13 and 1/3 times the sphaleron energy. It is found that the measured
rate is close to that predicted by one-loop calculation at the lower end of the
temperature range considered but falls at least an orderof magnitude short of
one-loop estimate at the upper end of that range. We show numerically that the
sphaleron approximation breaks down as soon as the gauge-invariant two-point
function yields correlation length close to the sphaleron size.


title: Framework for Identification of Neutral B Mesons

abstract:
  We introduce a method for the study of CP-violating asymmetries in tagged
states of neutral $B$ mesons with arbitrary coherence properties. A set of
time-dependent measurements is identified which completely specifies the
density matrix of the initial state in a two-component space with basis vectors
$B^0$ and $\overline B^0$, and permits a determination of phases in the
Cabibbo-Kobayashi-Maskawa matrix. For a given tagging configuration, the
measurement of decays both to flavor eigenstates and to CP eigenstates provides
the necessary information.


title:
Radiative Corrections to Higgs Boson Masses in the Next-to-Minimal
  Supersymmetric Standard Model

abstract:
  We perform a systematic study of radiative corrections to the masses of the
Higgs bosons in the minimal supersymmetric standard model (MSSM) augmented by a
single gauge singlet, the so-called next-to-minimal supersymmetric standard
model (NMSSM). Our method is based on the one-loop effective potential and
includes effects of top quark, squark, Higgs and Higgsino loops. We discuss the
renormalisation group flows of Yukawa couplings and the upper bound on the
lightest CP-even neutral Higgs boson mass as a function of the heavier stop
mass and top mass. We then give a general discussion of Higgs boson
phenomenology including radiative corrections. We survey as much of the
parameter space of the Higgs sector of the NMSSM as is practicable, and analyse
the full spectrum of Higgs masses and couplings in these regions of parameter
space. Characteristic signatures of the NMSSM such as light charged bosons and
weakly coupled neutral scalars are discussed, as are the relative sizes of the
various radiative corrections. The MSSM is also discussed as a limiting case of
the NMSSM for comparison.


title: Quantum Fluctuations around the Electroweak Sphaleron

abstract:
  We present an analysis of the quantum fluctuations around the electroweak
sphaleron and calculate the associated determinant which gives the 1--loop
correction to the sphaleron transition rate. The calculation differs in various
technical aspects from a previous analysis by Carson et al. so that it can be
considered as independent. The numerical results differ also -- by several
orders of magnitude -- from those of this previous analysis; we find that the
sphaleron transition rate is much less suppressed than found previously.


title:
Searching for $t\to ch^0$ or $h^0\to t\bar c$ at $e^+e^-$ Linear
  Colliders

abstract:
  Talk presented at 2nd International Workshop on Physics and Experiments with
Linear $e^+e^-$ Colliders (Hawaii, April 1993).


title: Experimental and Theoretical Implications of New Sequential Leptons

abstract:
  If new sequential leptons $E^\pm$ and $N^0$ exist, the LEP bound implies
$m_E$, $m_N > M_Z/2$. The heaviness of the neutral lepton breaks away from the
pattern of the first three generations. The minimal model is to have 4
left-handed lepton doublets and 4 right-handed charged lepton singlets, but
only one right-handed neutral lepton singlet. Since in general the 3rd and 4th
generation should mix, and since $\vert m_N - m_E\vert$ should not be too
large, neither $E$ nor $N$ would be stable, and both tend to decay via the
Cabibbo suppressed $E\to \nu_\tau$ or $N\to \tau$ charged currents. This leads
to the interesting signature of like-sign $W$ pair production via $E^+N \to
\bar\nu_\tau\tau^- W^+W^+$ at the SSC and LHC. The popular seesaw mechanism
cannot plausibly accommodate the near masslessness of the light neutrinos and
the heaviness of $N^0$ simultaneously. The representation structure poses a
difficulty to the traditional approach of $SO(10)$-based grand unified
theories. The discovery of such new heavy leptons would thus have rather wide
ranging and far reaching implications.


title: Simply Modeling B -> K* gamma

abstract:
  A simple relativistic model of heavy-light mesons is applied to the rare
decay B -> K* gamma in the standard model. We find Gamma(B -> K* gamma)/Gamma(b
-> s gamma)=(17 \pm 4)% and BR(B -> K* gamma)=(4.8 \pm 1.9) \times
10^{-5}(V_cb/.04)^2. These numbers are reduced by only 20% in the heavy-quark
limit.


title:
Observed Supersymmetry and Parity Doubling of Excited Hadrons from a
  Simple Spectrum-Generating Algebra

abstract:
  We find remarkable agreement with the observed excitations of hadrons with a
simple three parameter mass relation of the SU(3) subgroup of the underlying
U(15/30) graded Lie group. The baryons are the appropriate supersymmetric
partners of the mesons. An interesting feature, which is a focus of current
interest, is that the baryons and isobars show parity doubling. Significantly,
the ground state baryons and mesons have no place in the fit, so that the
parity doubling is indicated only when excitation energy is available. This has
correspondence with the parity doubling seen in recent lattice calculations,
when thermal excitation is present. The agreement with experiment is comparable
to the semi-relativistic quark model which fits with many force parameters and
where the observed parity doubling is accidental. The gross splitting of the
levels is the same for the strange and the non-strange sectors, suggesting
flavour independence.


title:
On the Spontaneous CP Breaking in the Higgs Sector of the Minimal
  Supersymmetric Standard Model

abstract:
  We revise a recently proposed mechanism for spontaneous CP breaking at finite
temperature in the Higgs sector of the Minimal Supersymmetric Standard Model,
based on the contribution of squarks, charginos and neutralinos to the one-loop
effective potential. We have included plasma effects for all bosons and added
the contribution of neutral scalar and charged Higgses. While the former have
little effect, the latter provides very strong extra constraints on the
parameter space and change drastically the previous results. We find that CP
can be spontaneously broken at the critical temperature of the electroweak
phase transition without any fine-tuning in the parameter space.


title: B-Quark Production at Hadron Colliders

abstract:
  Results for b-quark production at hadron colliders, both current and
proposed, are presented. Distributions in $p_t$ are presented for the TeVatron
and SSC. Confirmation of agreement between the ${\cal O}(\alpha_S^3)$
calculations and UA1 data is presented, and the discrepancy between the ${\cal
O}(\alpha_S^3)$ calculations and the CDF results is updated with the most
recent data.


title: Electromagnetic Moments of the Baryon Decuplet

abstract:
  We compute the leading contributions to the magnetic dipole and electric
quadrupole moments of the baryon decuplet in chiral perturbation theory. The
measured value for the magnetic moment of the $\Omega^-$ is used to determine
the local counterterm for the magnetic moments. We compare the chiral
perturbation theory predictions for the magnetic moments of the decuplet with
those of the baryon octet and find reasonable agreement with the predictions of
the large--$N_c$ limit of QCD. The leading contribution to the quadrupole
moment of the $\Delta$ and other members of the decuplet comes from one--loop
graphs. The pionic contribution is shown to be proportional to $I_z$ (and so
will not contribute to the quadrupole moment of $I=0$ nuclei), while the
contribution from kaons has both isovector and isoscalar components. The chiral
logarithmic enhancement of both pion and kaon loops has a coefficient that
vanishes in the $SU(6)$ limit. The third allowed moment, the magnetic octupole,
is shown to be dominated by a local counterterm with corrections arising at two
loops. We briefly mention the strange counterparts of these moments.


title:
CP Violation Induced by Heavy Majorana Neutrinos in the Decays of Higgs
  Scalars into Top-Quark, W- and Z-Boson Pairs

abstract:
  We analyze the possibility of $CP$ violation induced by heavy Majorana
neutrinos in the decays of the Higgs particle into top-quark, $W$- and
$Z$-boson pairs. In the framework of various ``see-saw" models with interfamily
mixings, we find that Majorana neutrinos may give rise to sizable $CP$-odd
observables at the one-loop electroweak order. Numerical estimates of these
$CP$-violating effects that may be detected in high-energy colliders are
presented.


title: Electromagnetic Signals and Backgrounds in Heavy-Ion Collisions:

abstract:
  Aspects of the dilepton spectrum in heavy-ion collisions are discussed, with
special emphasis on using lattice computations to guide the phenomenology of
finite temperature hadronic matter. The background rates for continuum
dileptons expected in forthcoming experiments are summarised. Properly
augmented by data from ongoing measurements at HERA, these rates will serve as
a calibrating background for QGP searches. Recent results on the temperature
dependence of the hadronic spectrum obtained in lattice computations below the
deconfinement transition are summarised. Light vector meson masses are strongly
temperature dependent. Accurate measurements of a resolved $\rho$-peak in
dimuon spectra in present experiments are thus of fundamental importance.
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title:
The matrix element for radiative Bhabha scattering in the forward
  direction

abstract:
  We present an approximation to the matrix element for the process e+e- -->
e+e-gamma, appropriate to the situation where one or both of the fermions are
scattered over very small angles. The leading terms in the situation where all
scattering angles are small contains not only terms quadratic in the electron
mass, but also quartic and even sextic terms must be included. Special
attention is devoted to the numerical stability of the resultant expression.
Its relation to several existing formulae is discussed.


title: Extended Gauge Sectors at Linear Colliders

abstract:
  Signatures of extended gauge models at high energy \epem\ linear colliders
are summarized. Talk presented at the Workshop on Physics and Experiments with
Linear \epem\ Colliders, Waikoloa, Hawaii, April 1993.


title: Anomalous Evolution of the Gottfried Sum

abstract:
  We discuss nonperturbative QCD evolution of nonsinglet nucleon structure
functions, with particular application to the Gottfried sum. We show that the
coupling of the quark partons to bound state mesons leads to nonperturbative
contributions to the Altarelli--Parisi equations which, due to the axial
anomaly, result in a strong scale dependence of nonsinglet structure functions
for values of $Q^2$ around the nucleon mass scale. We compute specifically the
evolution of the first moment of the quark distribution, and find that it is
sufficient to explain recent experimental data which indicate a violation of
the Gottfried sum rule.


title: SUSY GUTs: A practical introduction

abstract:
  An introduction to the most important concepts in the subject of
supersymmetric unified theories is presented. The emphasis is on the practical
aspects leading to state-of-the-art calculations in this renascent subject. The
topics covered include: generalities of supersymmetric unified theories, gauge
and Yukawa coupling unification including the most up-to-date numerical
analyses, soft supersymmetry breaking, and radiative electroweak symmetry
breaking enforced using the tree-level and one-loop effective potentials. This
class of supersymmetric models can be described in terms of five parameters:
the top-quark mass ($m_t$), the ratio of Higgs vacuum expectation values
($\tan\beta$), and three universal soft-supersymmetry-breaking parameters
($m_{1/2},m_0,A$). Thus, highly correlated predictions can be expected for all
conceivable experimental observables. In effect, these general models provide a
basic framework upon which more constrained models can be built.


title: Corrections to Bino Annihilation I: Sfermion Mixing

abstract: We consider corrections to bino annihilation due to sfermion mixing.


title:
Model Independent Properties and Cosmological Implications of the
  Dilaton and Moduli Sectors of 4-d Strings

abstract:
  We show that if there is a realistic 4-d string, the dilaton and moduli
supermultiplets will generically acquire a small mass O(m_{3/2}), providing the
only vacuum-independent evidence of low-energy physics in string theory beyond
the supersymmetric standard model. The only assumptions behind this result are
(i) softly broken supersymmetry at low energies with zero cosmological
constant, (ii) these particles interact with gravitational strength and the
scalar components have a flat potential in perturbation theory, which are
well-known properties of string theories. (iii) They acquire a $vev$ of the
order of the Planck scale (as required for the correct value of the gauge
coupling constants and the expected compactification scale) after supersymmetry
gets broken. We explore the cosmological implications of these particles.
Similar to the gravitino, the fermionic states may overclose the Universe if
they are stable or destroy nucleosynthesis if they decay unless their masses
belong to a certain range or inflation dilutes them. For the scalar states it
is known that the problem cannot be entirely solved by inflation, since
oscillations around the minimum of the potential can lead to a huge entropy
generation at late times. We discus some possible ways to alleviate this
entropy problem, that favour low-temperature baryogenesis, and also comment on
the possible role of these particles as dark matter candidates or as sources of
the baryon asymmetry through their decay.


title:
Prospects for Multiple Weak Gauge Boson Production at Supercollider
  Energies

abstract:
  We discuss the prospects for observing multiple weak gauge boson production
at the SSC and LHC. We summarize conventional perturbative cross sections for
processes involving 1-6 final state weak gauge bosons and compare them with
more speculative scenarios including 1) a toy model of a strongly interacting
Higgs sector patterned after hadronic multipion production and 2) the
nonperturbative production of O(30) weak gauge bosons in a weakly coupled gauge
sector.


title: $1/N_C$ Corrections to $g_A$ in the Light of PCAC$

abstract:
  We comment on recently discovered $1/N_C$ corrections to the ` nucleon axial
current in the framework of the Nambu--Jona-Lasinio soliton. This kind of
corrections arises only for a special treatment of ordering ambiguities of
collective coordinates and operators in the semiclassical quantization. In
addition to the missing derivation of this special quantization scheme from
first principles its na\"\i ve application violates partial conservation of the
axial current (PCAC). We show how within this scheme PCAC can be restored and
determine the corresponding $1/N_C$ corrections to the equation of motion for
the chiral soliton. The resulting self-consistent solution allows to evaluate
the nucleon axial coupling constant $g_A$ directly as a matrix element of the
axial current as well as indirectly from the pion profile function. Enhancement
is found for those baryon properties which are sensitive to the long range
behavior of the pion profile.


title:
Vector Meson Exchanges and CP Asymmetry in
  $K^{\pm}\rightarrow\pi^{\pm}\pi^0$

abstract:
  Using a current algebra framework, we discuss the contribution of vector
meson exchanges to the CP violating asymmetry in the decay
$K^{\pm}\rightarrow\pi^{\pm}\pi^0$, resulting from the interference of the
$K\rightarrow\pi\pi$ amplitude with the radiative correction
$K\rightarrow\pi\pi\gamma$.


title: Light Threshold Effects in Supersymmetric Grand Unified Theories

abstract:
  Supersymmetric Grand Unified Theories have a rich spectrum of particles
barely heavier than the intermediate vector bosons. As their non-supersymmetric
counterparts, they lead to many relations among low energy observables. But the
precise form of the predictions is modified by the extended spectrum. If the
masses of these new particles are comparable to $M_Z$, the standard computation
of their effect becomes inaccurate. We present a detail discussion of the
correct procedure, and carry out the relevant computations to one loop order.
The procedure we propose has the advantage over other existing methods that
two-loop running of gauge couplings can be incorporated readily and
consistently. Attention is paid to the special treatment that the top and Higgs
particles must receive. The size of the effect is explored for a range of
parameters in the minimal supersymmetric $SU(5)$ grand-unified theory with
radiative breaking. It is found that the naive (leading-log) computation can be
fairly inaccurate.


title: Production of $Z$ Boson Pairs at Photon Linear Colliders

abstract:
  The $ZZ$ pair production rate in high energy $\gamma \gamma$ collisions is
evaluated with photons from laser backscattering. We find that searching for
the Standard Model Higgs boson with a mass up to, or slightly larger than, 400
GeV via the $ZZ$ final state is possible via photon fusion with backscattered
laser photons at a linear $e^+e^-$ collider with energies in the range 600 GeV
$< \sqrt{s_{e^+e^-}} <$ 1000 GeV.


title: Theory of Gauge Boson Structure

abstract:
  Based on an Invited Plenary Talk given at ``Workshop on Physics and
Experiments with Linear $e^+e^-$ Colliders,'' Waikoloa, Hawaii, April 26--30,
1993. This paper reviews theoretical issues concerning the structure of vector
bosons, with emphasis on deviations of triple-vector-boson interactions from
the predictions of the Standard Model. Particular emphasis is on the role of
gauge invariance in understanding the behavior of vector particles over energy
scales large compared to their masses.


title: Effective Field Theory for Diffractive QCD Processes

abstract:
  An effective field theory describing the QCD diffraction scattering is
constructed. The constituent quarks interacting with multiperi- pheral gluons
and Goldstone bosons are described by impact- parameter two-dimensional sigma
models for the color and the flavor degrees of freedom. The elastic scattering
amplitude is then shown to factorize into the hard and the soft pomeron
contributions (talk at 5th Blois Workshop on Elastic and Diffractive Scattering
Workshop, June 8 - 12, 1993, Providence RI USA)


title: A Systematic SO(10) Operator Analysis for Fermion Masses

abstract:
  A new approach for deducing the theory of fermion masses at the scale of
grand unification is proposed. Combining SO(10) grand unification, family
symmetries and supersymmetry with a systematic operator analysis, the minimal
set of fermion mass operators consistent with low energy data is determined.
Exploiting the full power of SO(10) to relate up, down and charged lepton mass
matrices, we obtain predictions for 7 of the mass and mixing parameters. The
assumptions upon which the operator search and resulting predictions are based
are stressed, together with a discussion of how the predictions are affected by
a relaxation of some of the assumptions.The masses of the heaviest generation,
$m_t,m_b$ and $m_\tau$, are generated from a single renormalizable Yukawa
interaction, while the lighter masses and the mixing angles are generated by
non-renormalizable operators of the grand unified theory. The hierarchy of
masses and mixing angles is thereby related to the ratio of grand to Planck
scales, $M_G / M_P$. An explicit realization of the origin of such an
economical pattern of operators is given in terms of a set of spontaneously
broken family symmetries. In the preferred models the top quark is found to be
heavy: $M_t = 180 \pm 15$ GeV, and $\tan \beta$ is predicted to be very large.
Predictions are also given for $m_s, m_s/m_d , m_u/m_d, V_{cb}, V_{ub}/V_{cb}$
and the amount of CP violation. Stringent tests of these theories will be
achieved by more precise measurements of $M_t, V_{cb}, \alpha_s$ and $
V_{ub}/V_{cb}$ and by measurements of CP violation in neutral B meson decays.


title:
Infinite Renormalization of Theta-Term and Jarlskog Invariant for
  CP-Violation

abstract:
  The logarithmic ultraviolet divergence in the theta-term induced by
electroweak interactions in the Kobayashi-Maskawa model of CP-violation, found
by Ellis and Gaillard, is discussed. We relate it to the Jarlskog CP-odd
invariant of quark mass matrix. The divergence arises in 14th order in Higgs
coupling as well as in 12th order plus 2nd order in U(1) gauge boson coupling.


title:
Renormalization Group Study of the Standard Model and its Extensions:
  II. the Minimal Supersymmetric Standard Model

abstract:
  In this paper we summarize the minimal supersymmetric standard model as well
as the renormalization group equations of its parameters. We proceed to examine
the feasability of the model when the breaking of supersymmetry is parametrized
by the soft terms suggested by supergravity theories. In such models, the
electroweak symmetry is exact at tree level and is broken spontaneously at one
loop order. We make the additional assumption that the GUT-inspired relation
$m_b=m_\tau$ be valid at the scale where the gauge coupling constants unify,
which constrains the value of the top quark mass. For all types of soft
breaking terms expected in supergravity theories, we present the results of
numerical runs which yield electroweak breaking at the required scale. These
yield not only the allowed ranges for the soft supersymmetry breaking
parameters, but also the value of the supersymmetric partner' masses. For
example in the strict no-scale model, in which global supersymmetry breaking
arises solely from soft supersymmetry breaking parameters, but also the value
of the supersymmetric partner' masses. For example in the strict no-scale
model, in which global supersymmetry breaking arises solely from soft gaugino
masses, we find that $M_t$ can be no heavier than $\sim 127$ GeV.


title: "Large $(g-2)_\mu$ in SU(5)xU(1) supergravity models"

abstract:
  We compute the supersymmetric contribution to the anomalous magnetic moment
of the muon within the context of $SU(5)\times U(1)$ supergravity models. The
largest possible contributions to $a^{susy}_\mu$ occur for the largest allowed
values of $\tan\beta$ and can easily exceed the present experimentally allowed
range, even after the LEP lower bounds on the sparticle masses are imposed.
Such $\tan\beta$ enhancement implies that $a^{susy}_\mu$ can greatly exceed
both the electroweak contribution ($\approx1.95\times10^{-9}$) and the present
hadronic uncertainty ($\approx\pm1.75\times10^{-9}$). Therefore, the new E821
Brookhaven experiment (with an expected accuracy of $0.4\times10^{-9}$) should
explore a large fraction (if not all) of the parameter space of these models,
corresponding to slepton, chargino, and squarks masses as high as 200, 300, and
1000 GeV respectively. Moreover, contrary to popular belief, the $a^{susy}_\mu$
contribution can have either sign, depending on the sign of the Higgs mixing
parameter $\mu$: $a^{susy}_\mu>0\,(<0)$ for $\mu>0$ ($\mu<0$). The present
$a_\mu$ constraint excludes chargino masses in the range $45-120\GeV$ depending
on the value of $\tan\beta$, although there are no constraints for
$\tan\beta\lsim8$. We also compute $a^{susy}_\tau$ and find
$|a^{susy}_\tau|\approx(m_\tau/m_\mu)^2\,|a^{susy}_\mu|\lsim10^{-5}$ and
briefly comment on its possible observability.


title: Properties of Orbitally Excited Heavy-Light Mesons

abstract:
  Orbitally excited heavy-light mesons are potentially important as tools for
tagging the flavors and momenta of ground-state pseudoscalars detected through
weak decays. We use heavy-quark symmetry supplemented by insights gleaned from
potential models to estimate masses and widths of $p$-wave $B$, $B_s$, and
$D_s$ mesons. We generalize these results to higher excitations.


title:
On the asymptotic ${\cal O}(\alpha \alpha_S)$ behavior of the
  electroweak gauge bosons vacuum polarization functions for arbitrary quark
  masses

abstract:
  We derive the QCD corrections to the electroweak gauge bosons vacuum
polarization functions at high and zero--momentum transfer in the case of
arbitrary internal quark masses. We then discuss in this general case (i) the
connection between the $O(\alpha \alpha_S)$ calculations of the vector bosons
self--energies using dimensional regularization and the one performed via a
dispersive approach and (ii) the QCD corrections to the $\rho$ parameter for a
heavy quark isodoublet.


title: New Fermions at e$^+$e$^-$ Colliders: I. Production and Decay

abstract:
  We analyze the production in $e^+e^-$ collisions of new heavy fermions
stemming from extensions of the Standard Model. We write down the most general
expression for the production of two heavy fermions and their subsequent
decays, allowing for the polarization of the e$^+$e$^-$ initial state and
taking into account the final polarization of the fermions. We then discuss the
various decay modes including cascade and three body decays, and the production
mechanisms, both pair production and single production in association with
ordinary fermions.


title: New Fermions at e$^+$e$^-$ Colliders: II.~Signals and Backgrounds

abstract:
  We discuss the production, at high--energy e$^+$e$^-$ linear colliders, of
new heavy fermions predicted by extensions of the Standard Model. We analyze in
great details the various signals and the corresponding backgrounds for both
pair production and single production in association with ordinary fermions.
Concentrating on new leptons, we use a model detector for e$^+$e$^-$ collisions
at a center of mass energy of 500 GeV, to illustrate the discovery potential of
the Next Linear Colliders.


title: Remarks on Hot QCD

abstract:
  After briefly reviewing work I've done recently with Krishna Rajagopal on the
nature of the equilibrium phase transition in QCD at finite temperature and
zero baryon number and on the possibility of forming misaligned vacuum by a
quench, I discuss -- also briefly -- two new items. These are extension of the
arguments concerning the order of the transition to to 2+1 dimensions, relating
in this case gauge to conformal field theories, that could be explored in
numerical experiments; and the energy budget at the chiral transition and its
relevance to the nature of the transition and to quenching.


title:
{\Large{\bf Higgs or Neutral Vector Boson Production with a $W$ Pair in
  {\LARGE $\gamma \gamma$} Collisions}}

abstract:
  Exploiting the fact that $W$ pair production in high-energy $\gamma \gamma$
collisions is very large, we use this process to trigger Higgs, $Z$ or photon
radiation. We find that there are sizeable rising cross-sections for triple
bosons production. At energies about $1TeV$ the new mechanism for Higgs
production becomes very competitive with the dominant Higgs production
processes in $e^+e^-$ and $e \gamma$ reactions. The effect of different
polarized photon spectra obtained through back-scattered laser light on the
electron beam of a linear collider is investigated . We give a special
attention to the search of the intermediate mass Higgs in $WWH$ production and
discuss how to effectively suppress the backgrounds.


title:
Tests on the Hierarchy of Trilinear and Quadrilinear Weak Bosons
  Couplings at the NLC and Comparison with the LHC/SSC

abstract:
  I first review a few basic guiding principles that lead to the notion of a
hierarchy of couplings in searches of New Physics involving weak bosons
processes. The hierarchies within a linear and a non-linear realization of
symmetry breaking are compared to the usual {\em phenomenological}
parameterization of the $WWV$ vertex. Limits that one expects to obtain at the
NLC(500GeV) and LHC/SSC on the tri-linear and quadri-linear anomalous $W$
couplings are compared. The cleanness of an \epm gives the NLC a clear
advantage in constraining the tri-linear couplings. However, with ``only"
$500$GeV, the \epm is not competitive with $pp$ colliders in probing the
quadri-linear couplings. An interpretation in terms of scalar-like and
vector-like models is given and I argue that in the presence of a light (or
``not-so-heavy") Higgs, the New Physics affecting the $W$ sector would be
easier to pin-down with a moderate energy \epm machine.


title: Observation of D+ -> rho0(770) mu+ nu

abstract:
  We report the first observation of the Cabibbo disfavored semileptonic decay
mode D+ -> rho0(770) mu+ nu, and measure its decay rate relative to the Cabibbo
favored mode D+ -> K*0(892) mu+ nu to be Gamma(D+ -> rho0(770) mu+ nu) /
Gamma(D+ -> K*0(892) mu+ nu) = 0.044 +0.031 -0.025 (stat.) +/- 0.014 (sys). The
results are compared to theoretical predictions and to previous experimental
upper limits.


title: Where is Top?

abstract:
  Possibilities are discussed for determining the top quark mass $m_t$ from
observations on the decay processes for top-antitop pairs produced in
antiproton-proton collisions, assuming that the $t \to bW^+$ decay channel is
dominant and much faster than hadronization. The final states $t \bar{t} \to
\bar{b} b \mu^\pm e^\mp$ provide the most striking signal, with little
background, but they are rare ($\approx 2/81$). If all candidate events prove
to be from $t \bar{t}$, an estimate follows for $P(m_t|rate)$, the probability
distribution for $m_t$. The one reported configuration allows an independent
estimate for $P(m_t|\mu^\pm e^\mp \,2jets)$. These two distributions are
compatible,yielding an estimate of about 122 GeV. Decay events ``1 energetic
lepton($l$) + 4jets'' should appear twelve times as often as ``$\mu^\pm e^\mp
\,2jets$'' events and can be analysed to give estimates for $P(m_t|l\, 4jets)$.
There may be background from non-top events but suitable cuts on the data and
our analysis procedure together reduce this to a low level. The rate observed
for these events does not appear to be as large as this factor 12.
Identification of either or both of the $(b \bar{b})$ jets would be a great
step forward. We advocate an energetic approach to the analysis of individual
events on an event by event basis, with the hope of finding a subgroup of
events with a common mass estimate.


title:
Experimental Constraints on the Scale of New Physics in Top Condensate
  Models

abstract:
  We obtain mass limits on the extra neutral gauge boson which is predicted in
a model with hidden gauge symmetry and dynamical breaking of the electroweak
symmetry by a top quark condensate. For typical model assumptions, present LEP
data exclude masses below 3\,TeV. With LEP200 or an electron-positron collider
of a c.m. energy of 500 GeV masses below 15\,TeV or 50\,TeV could be excluded,
respectively. Such high mass limits allow the calculation of the observables
used in the analysis in the context of the Nambu-Jona-Lasinio model.


title: Anomalous Higgs Boson Production and Decay

abstract:
  A non-standard symmetry breaking sector may lead to derivative couplings of
the Higgs boson and thereby to anomalous interactions with the electroweak
gauge bosons. In the framework of gauge-invariant effective Lagrangians the
resulting changes in Higgs boson production and decay mechanisms are related to
anomalous triple vector boson couplings. Using low energy constraints on the
dimension-six operators in the effective Lagrangian, we discuss the size of
deviations from SM predictions which may be expected in Higgs boson production
and decay rates. Large enhancements are allowed {\it e.g.} in the $Z \to H
\gamma$ and $H\to \gamma \gamma$ partial decay widths, leading to $Z\to
\gamma\gamma\gamma$ events at LEP.


title: Common Origin for the Solar and Atmospheric Neutrino Deficits

abstract:
  Some typos corrected, slightly different abstract, same plots, results and
conclusions.


title:
Exact $\alpha _s$ Calculation of $b\rightarrow s + \gamma $, \
  $b\rightarrow s + g$

abstract:
  We present an exact $\alpha_s$ calculation of the Wilson coefficients
associated with the dipole moment operators. We also give an estimate of the
branching ratio for $b\rightarrow s \gamma$. We find that higher dimensional
effects are under control within $9\%$ for $BR(b\rightarrow s \gamma)=(4.3\pm
0.37 )\times 10^{-4}$.


title:
Hadronic Molecules and Scattering Amplitudes from the Nonrelativistic
  Quark Model

abstract:
  This report summarizes recent calculations of low-energy hadron-hadron
scattering amplitudes in the nonrelativistic quark potential model, which
assume that the scattering mechanism is a single interaction (usually OGE)
followed by constituent interchange. We refer to the scattering diagrams as
``quark Born diagrams". For the cases chosen to isolate this mechanism, I=2
$\pi\pi$, I=3/2 K$\pi$, KN and NN, the results are usually in good agreement
with experimental S-wave scattering amplitudes given standard potential-model
parameters. These calculations also lead to predictions of vector-vector bound
states, one of which may be the $\theta(1710)$. This assignment can be tested
by searches for K$\bar{\rm K}\pi\pi$ and $\phi\pi^0\gamma$ decay modes of the
$\theta(1710)$.


title: Introduction to Chiral Perturbation Theory

abstract:
  An introduction to the basic ideas and methods of Chiral Perturbation Theory
is presented. Several phenomenological applications of the effective Lagrangian
technique to strong, electromagnetic and weak interactions are discussed.


title:
Can $\mu$--$e$ Conversion in Nuclei be a Good Probe for Lepton-Number
  Violating Higgs Couplings ?

abstract:
  Motivated by the improving sensitivity, $R$, of experiments on $\mu~Ti
\rightarrow e~Ti$ and the enhanced Higgs nucleon interaction, we study this
lepton number violating process induced by Higgs exchange. Taking the possible
sensitivity, $R \simeq 10^{-16}$, we obtain the constraint on the
Higgs-muon-electron vertex, $\kappa_{\mu e}$, to be less than
$2.4\times10^{-7}$ if the masses of the Higgs scalar and $W$ gauge boson are
the same. $\kappa_{\mu e}$ is also calculated for some models.


title: Triple Vector Boson Processes in $\gamma\gamma$ Colliders

abstract:
  We study the production of three gauge bosons at the next generation of
linear $e^+e^-$ colliders operating in the $\gamma\gamma$ mode. The processes
$\gamma\gamma \rightarrow W^+W^-V$ ($V=Z^0$, or $\gamma$) can provide direct
information about the quartic gauge-boson couplings. We analyze the total cross
section as well as several dynamical distributions of the final state particles
including the effect of kinematical cuts. We find out that a linear $e^+e^-$
machine operating in the $\gamma\gamma$ mode will produce 5--10 times more
three-gauge-boson states compared to the standard $e^+e^-$ mode at high
energies.


title: Rare Supersymmetric Top Quark Decays

abstract:
  {Two supersymmetric decays of the top quark, $\thb$ and $\tstopneu$, are
discussed within the framework of the Minimal Supersymmetric Standard Model
with radiatively induced breaking of $SU(2)\times U(1)$. The present
possibility of detecting these decays, given the available bounds on
supersymmetric parameters, is compared with the situation a Next $e^+e^-$
Linear Collider would face if supersymmetric particles were still undiscovered
after LEP~II. The indirect implications for $\thb$ and $\tstopneu$ of a
possible detection of the bottom quark decay $\bsgamma$ at the Standard Model
level are taken into account. } % Invited talk presented to the {\it Workshop
on Physics and
  Experiments with Linear $e^+e^-$ Colliders}, Waikoloa, Hawaii, April 1993


title:
Emergence of long wavelength pion oscillations following a rapid QCD
  phase transition

abstract:
  To model the dynamics of the chiral order parameter in a far from equilibrium
QCD phase transition, we consider quenching in the O(4) linear sigma model. We
summarize arguments and numerical evidence which show that in the period
immediately following the quench arbitrarily long wavelength modes of the pion
field are amplified. This results in large regions of coherent pion
oscillations, and could lead to dramatic phenomenological consequences in
ultra-relativistic heavy ion collisions. My talk was a description of work done
with Frank Wilczek. In these proceedings, I sketch our central results,
emphasizing several points that were raised in discussions at the conference.


title: Chiral symmetry and many-body nonleptonic decays of bottom hadrons

abstract:
  Chiral symmetry can be applied to many-body nonleptonic decays of heavy
hadrons. We establish the chiral effective Hamiltonian for some typical
many-body nonleptonic decays of bottom hadrons. We discuss the lowest-order
contributions coming from such a Hamiltonian and present, as an example, a
calculation of decay distributions of $B^-\to D^+ D^-_s \pi^-$ and $B^-\to
D^{\ast +} D^-_s \pi^-$. We emphasize that wide applications of this method are
possible.


title:
Unification of Couplings and the Top Quark Sector in the Minimal
  Supersymmetric Standard Model

abstract:
  I analyze the predictions for the strong gauge coupling, $\alpha_3(M_Z) $,
and the top quark and light Higgs masses in the framework of gauge and
bottom-tau Yukawa coupling unification in the minimal supersymmetric standard
model. These predictions depend on the effective supersymmetric threshold scale
$T_{SUSY}$, which is only very slightly dependent on the squark and slepton
masses, and strongly dependent on the Higgsino masses as well as on the mass
ratio of the gauginos of the strong and weak interactions. Within the minimal
supersymmetry breaking scheme and for supersymmetric masses below or of the
order of 1 TeV, I obtain $\alpha_3(M_Z) \geq 0.116$, while, if the running
bottom quark mass at the physical mass is constrained to be $ m_b(M_b) \leq 4.1
$GeV, then, for moderate values of $\tan \beta$, perturbative unification is
achieved only if $\alpha_3(M_Z) \leq 0.124$. Unification of gauge and
bottom-tau Yukawa couplings yield predictions for the top quark mass, 140 GeV
$\leq M_t \leq 210 $ GeV for $1 \leq \tan \beta \leq 30$, which are remarkably
close to the infrared quasi fixed point values for this quantity. For the light
Higgs mass I obtain $m_h \leq 130(165)$ GeV if the characteristic squark mass
is below 1 (10) TeV.


title: Multiple Muons From Neutrino-Initiated Multi-W(Z) Production

abstract:
  Current underground detectors can search for multiple muons from multi-W(Z)
production initiated by ultrahigh energy neutrinos from active galactic nuclei.
O($\mu$b) cross sections give rise to downward going muon bundles whose
features differ from those of atmospheric muon bundles.


title: Soft Gluon Radiation in Hadronic $t\bar t$ Production

abstract:
  We investigate soft gluon radiation in hadronic $t\bar t$ production. By
taking the top quark decay properly into account, we are able to study the
interplay of radiation both before and after the decay of the top quarks. The
production--decay and decay--decay radiative interferences depend sensitively
on the relative size of the gluon energy and the decay width. Radiation
patterns for various production mechanisms are compared.


title: Gauge-Boson Production in Electron-Photon Collisions

abstract:
  We summarize results for the processes $e^-\gamma \to \nu W^-, e^-Z,
e^-\gamma$ within the electroweak Standard Model. We discuss the essential
features of the corresponding lowest-order cross-sections and present numerical
results for the unpolarized cross-sections including the complete $O(\alpha)$
virtual, soft-photonic, and hard-photonic corrections. While at low energies
the weak corrections are dominated by the leading universal corrections, at
high energies we find large, non-universal corrections, which arise from vertex
and box diagrams involving non-Abelian gauge couplings.


title:
Large N Relations Between Mass Matrix And Gauge Group In Electroweak
  Gauge Extensions With Strong Coupling

abstract:
  The Large N expansion in gauge models with an NJL mechanism is discussed in
view of the resulting fermionic mass matrix. A hidden symmetry model is
introduced.


title: Nucleon Solution of the Faddeev Equation in the Nambu-Jona-Lasinio Model

abstract:
  Given the phenomenological success of the Nambu-Jona-Lasinio model in
describing the meson physics in the low energy limit, it is tempting to find
the fully relativistically structured nucleon solution in the same model under
the similar approximation employed in the mesonic sector. To achieve this goal
we need to solve a relativistic Faddeev equation. The factorizability of the
two-body T-matrix reduces the three-body Faddeev equation to a tractable
two-body Bethe-Salpeter equation. The reduced equation is then solved
numerically. Our result indicates that the nucleon consists of three loosely
bound constituent quarks.


title: (S)quark Masses and Non-Abelian Horizontal Symmetries

abstract:
  We present a model of quark and squark masses which is based on a non-Abelian
horizontal symmetry. It leads to order of magnitude relations between quark
mass ratios and mixing angles and to the successful exact relation $\sin
\theta_C=\sqrt {m_d\over m_s}$ to better than $20\%$ accuracy. The non-Abelian
symmetry also ensures the necessary squark degeneracy to suppress FCNC mediated
by loops with squarks and gluinos, in the neutral meson systems.


title:
Radiatively-Induced First-Order Phase Transitions: The Necessity of the
  Renormalization Group

abstract:
  We advocate a (Wilson) renormalization-group (RG) treatment of
finite-temperature first-order phase transitions, in particular those driven by
radiative corrections such as occur in the standard model, and other
spontaneously-broken gauge theories. We introduce the scale-dependent
coarse-grained free energy $S_\La[\phi]$ which we explicitly calculate, using
the Wilson RG and a $(4-\ep)$-expansion, for a scalar toy model that shares
many features of the gauged case. As argued by Langer and others, the dynamics
of the phase transition are described by $S_\La[\phi]$ with $\La$ of order the
bubble wall thickness, and {\it not} by the usual (RG-improved)
finite-temperature effective action which is reproduced by $S_\La[\phi]$ for
$\La\to 0$. We argue that for weakly first-order transitions (such as that in
the standard model) the $(4-\ep)$-expansion is necessary to control an
inevitable growth of the effective scale-dependent coupling towards the
strong-coupling regime, and that diagrammatic resummation techniques are
unlikely to be appropriate.


title: Gauge Coupling Unification: Strings versus SUSY-GUTs

abstract:
  Standard (level one) heterotic string models with standard model gauge group
predict the unification of $SU(3)$ and $SU(2)$ gauge couplings whereas the
$U(1)$ factor is unified modulo an unknown normalization factor $k_1$. On the
other hand the unification mass is known. I argue that this situation is quite
analogous (though opposite) to that in SUSY-GUTs in which the $U(1)$
normalization is known ($k_1=5/3$) but the unification mass $M_X$ is unknown. I
emphasize that $k_1$ should be taken as a free parameter in the string approach
(quite in the same way as $M_X$ is taken as a free parameter in SUSY-GUTs). If
this is done, the success of the string approach concerning gauge coupling
unification is comparable to that in SUSY-GUTs


title:
One Loop Calculation of the $\epsilon_3$ Parameter within the Extended
  Bess Model

abstract:
  The existence of a strongly interacting sector responsible for the
electroweak symmetry breaking is assumed. As a consequence vector and
axial-vector bound states may be formed. These resonances mix with the Standard
Model gauge bosons and are of primary phenomenological importance for the LEP
physics. The extended BESS model is an effective scheme based on the symmetry
group $SU(8)_L\otimes SU(8)_R$, describing in a consistent way the interactions
among the pseudo-Goldstone bosons, vector and axial-vector resonances and the
standard gauge bosons. In a previous paper, the contribution from extended BESS
to the electroweak oblique corrections was evaluated. However, only an estimate
of the effects coming from mass and wave function renormalization of the new
resonances, was given. Here we complete the evaluation by computing explicitly
these effects. We confirm the previous result, that is, in spite of the great
precision of the present LEP measurements, the extended BESS parameter space is
not very much constrained.


title:
Dynamical Symmetry Breaking In A Nambu-Jona-Lasinio Model And The Vacuum
  Structure

abstract:
  The vacuum structure for a Nambu-Jona -Lasinio type model is studied using
the effective potential approach. The relevant degrees of freedom are taken to
be two different sets of static, auxiliary fields with different symmetry
properties, related by Fierz transformations in the action. The results are
compared with the analysis of the Dyson-Schwinger equations in the one-loop
approximation.


title: Charmonium Physics at a Tau-Charm Factory

abstract:
  This talk summarizes the status of the charmonium system, with particular
emphasis on outstanding problems in QCD spectroscopy which a tau-charm factory
can address.


title: Short-Distance Expansion of Heavy-Light Currents at Order 1/m

abstract:
  The short-distance expansion of the heavy-light currents $\bar q\,\gamma^\mu
Q$ and $\bar q\,\gamma^\mu\gamma_5\,Q$ is constructed to order $1/m_Q$, and to
next-to-leading order in renormalization-group improved perturbation theory. It
is shown that the $10\times 10$ anomalous dimension matrix, which describes the
scale dependence of the dimension-four effective current operators in the heavy
quark effective theory, is to a large extent determined by the equations of
motion, heavy quark symmetry, and reparameterization invariance. The
next-to-leading order expressions for the Wilson coefficients at order $1/m_Q$
depend on only five unknown two-loop anomalous dimensions, among them that of
the chromo-magnetic operator.


title:
The Charm Content of W+1 Jet Events as a Probe of the Strange Quark
  Distribution Function

abstract:
  We investigate the prospects for measuring the strange quark distribution
function of the proton in associated $W$ plus charm quark production at the
Tevatron. The $W+c$ quark signal produced by strange quark -- gluon fusion,
$sg\rightarrow W^-c$ and $\bar sg\rightarrow W^+\bar c$, is approximately 5\%
of the inclusive $W+1$ jet cross section for jets with a transverse momentum
$p_T(j)>10$~GeV. We study the sensitivity of the $W$ plus charm quark cross
section to the parametrization of the strange quark distribution function, and
evaluate the various background processes. Strategies to identify charm quarks
in CDF and D\O \ are discussed. For a charm tagging efficiency of about 10\%
and an integrated luminosity of 30~pb$^{-1}$ or more, it should be possible to
constrain the strange quark distribution function from $W+c$ production at the
Tevatron.


title: Identification of Neutral B Mesons Using Correlated Hadrons

abstract:
  The identification of the flavor of a neutral $B$ meson can make use of
hadrons produced nearby in phase space. Examples include the decay of
``$B^{**}$'' resonances or the production of hadrons as a result of the
fragmentation process. Some aspects of this method are discussed, including
time-dependent effects in neutral $B$ decays to flavor states, to eigenstates
of CP and to other states, and the effects of possible coherence between $B^0$
and $\overline{B}^0$ in the initial state. We study the behavior of the leading
hadrons in $b$-quark jets and the expected properties of $B^{**}$ resonances.
These are extrapolated from the corresponding $D^{**}$ resonances, of whose
properties we suggest further studies.


title:
Bottom Quark Cross Sections at Collider and Fixed-Target Energies at the
  SSC and LHC

abstract:
  Calculations of inclusive cross sections for the production of bottom quarks
in proton-proton collisions are presented as a function of energy, transverse
momentum, and Feynman $x_F$ for values of $\sqrt{s}$ from $100~$GeV to
$40~$TeV. In addition, we provide simple parametrizations of our theoretical
results that should facilitate estimates of rates, acceptances, and
efficiencies of proposed new detectors.


title: Astroparticle Physics with High Energy Neutrino Telescopes

abstract:
  The first optical modules of the Baikal high energy neutrino telescope have
recently been deployed. Commissioning of the AMANDA, DUMAND and NESTOR
detectors will follow soon. Before discussing the detectors we review the
arguments that pinpoint $0.1\rm~km^2$ as the natural scale of a neutrino
telescope. Though present detectors do not quite reach this goal, their
techniques, if successful, can be exploited to build km$^2$ detectors for a
cost not exceeding one hundred million dollars. Motivations for the
construction of km$^2$ deep underground detectors include i) neutrino astronomy
and the search for cosmic accelerators, ii) neutrino oscillations using the
atmospheric neutrino beam, iii) the search for neutrinos from the annihilation
of dark matter particles in our galaxy, iv) the possibility to observe thermal
neutrino emission from supernovae, and v) to make the serendipitous discovery.
No astronomical telescope, detecting photons of any wavelength, has ever viewed
sites in the Universe shielded by more than a few hundred grams of matter.


title: Just How Strange? Loops, Poles and the Strangeness Radius of the Nucleon

abstract:
  We consider a simple model for the strangeness radius of the nucleon. The
model is based on vector meson dominance (VMD) and $\omega - \phi$ mixing in
addition to a kaon cloud contribution. We find that the VMD contribution is
similar in magnitude and of the same sign as the kaon contribution to the Sachs
strangeness radius and is significantly larger than the kaon contribution to
the Dirac radius. Two figures (not included) can be obtained through the
authors (marina@quark.umd.edu).


title: 14th International Workshop on Weak Interactions: Concluding Remarks

abstract:
  This superbly organized workshop invited the participants to focus on four
outstanding questions in weak interactions: i) is the electroweak model correct
at the quantum level? ii)supersymmetry? iii) neutrino mass? iv) what is the
nature of CP-violation? The meeting demonstrated how weak-interaction physics
has become a terrain successfully covered by accelerator and non-accelerator
experiments in a very complimentary way.


title: Detecting Top Squarks at the Tevatron Collider

abstract:
  We study the signal from the pair production of $t$-squarks at the Tevatron
under the assumption that their two-body decay to charginos as well as their
three-body decay to $W$ bosons is kinematically forbidden. In this case, the
stop dominantly decays via $\widetilde{t_1}\rightarrow c\tz_1$, so that the
signal consists of two charm jets together with $\eslt$. We reevaluate this
signal using ISAJET~7.01, and show that if the stop mass is below about 100
GeV, there should be as many as 50-70 events in the accumulated data sample of
the CDF and D0 experiments even if the LSP is as heavy as 50 GeV. We have also
studied the possibility of tagging the $c$-jet by its semileptonic $\mu$ decay,
but find that the event rates are too small for this to be viable except for
values of stop and LSP masses that yield a robust signal via the conventional
$\eslt$ search.


title: Aspects of Neutralino Dark Matter

abstract:
  The possible solution of dark matter problem with neutralinos of
supersymmetric models within the supergravity framework is reviewed. A novel
correlation between the neutralino relic abundance $\Omega_\chi$ and the soft
supersymmetry breaking patterns is demonstrated. It is explained that, this
generic result together with the proton-decay constraint could significantly
reduce the allowed parameter space of the minimal $SU(5)$ supergravity model,
and therefore makes this model more easily testable. The prospect of obtaining
further cosmological constraints from underground experiments for the minimal
$SU(5)$ supergravity model is also briefly discussed.


title: Beyond the Standard Model in Tau Decays

abstract:
  Invited talk at Second Workshop on JINR CTau Factory, Dubna, April 1993,
updated version of earlier review given at Second Workshop on Tau Lepton
Physics, Ohio, september 1992


title: Recent Progress in the Physics of Neutrino Mass

abstract:
  Invited lecture at Int. School on Particles and Cosmology, Baksan Valley,
1993


title: CP-Violation in Bosonic Sector of SM with two Higgs Doublets

abstract:
  We investigate CP-violation effects in the bosonic sector of the Standard
Model (SM) with two Higgs doublets. First we calculate the mass eigenstates of
the physical neutral Higgses for small but nonzero CP-violation parameter
$\xi_{\ast}$, and then a ``forward-backward'' asymmetry ${\cal A}_{fb}$ for the
decay $H \to W^+W^-Z$ that would be a signal of CP-violation. Although the
effects are in general small (${\cal A}_{fb} = \Gamma_{fb}/\Gamma \sim {\cal
O}(10^{-3})$), ${\cal A}_{fb}$ turns out to be a rather clean signal of
CP-violation, since neither the CP-conserving final state interactions nor the
direct production background events contribute to $\Gamma_{fb}$. The process is
a counterexample to the widespread belief that CP-violation processes must
involve fermions. The CKM-type CP-violation effects that could in principle
also contribute to ${\cal A}_{fb}$ are negligible. The nonzero ${\cal A}_{fb}$
could possibly be detected at some later stage in future colliders such as LHC
or SSC.


title:
An Analytic Formula and an Upper Bound for epsilon'/epsilon in the
  Standard Model

abstract:
  Using the idea of the penguin box expansion we find an analytic expression
for epsilon'/epsilon in the Standard Model as a function of m_t, m_s(m_c) and
two non-perturbative parameters B_6 and B_8. This formula includes
next-to-leading QCD/QED short distance effects calculated recently by means of
the operator product expansion and renormalization group techniques. We also
derive an analytic expression for the upper bound on epsilon'/epsilon as a
function of |V_cb|, |V_ub/V_cb|, B_K and other relevant parameters. Numerical
examples of the bound are given.


title: Two-Jet Hadroproduction as a Measure of the Gluon at Small X

abstract:
  We investigate the proposal of the CDF collaboration that same-side two-jet
production in $p\bar{p}$ collisions may be used to determine the gluon
distribution at small $x$.


title: Partial wave amplitudes and multiparticle production

abstract:
  Recursion relations for integrals of amplitudes over the phase space, i.e.
for partial wave amplitudes, are introduced. In their simplest form these
integrals are proportional to the s-wave amplitudes and represent rigorous
lower bounds on the total cross sections. The connection with classical field
equations in $D$ dimensions is established. Previous results on multiparticle
amplitudes are easily reproduced.


title: The $SU(2)$ Global Anomaly Through Level Circling

abstract:
  We discuss a novel manifestation of the $SU(2)$ global anomaly in an $SU(2)$
gauge theory with an odd number of chiral quark doublets and arbitrary Yukawa
couplings. We argue that the massive 4-dim.($D=4$) Euclidean Dirac operator is
nonhermitean with its spectrum of eigenvalues $(\lambda,-\lambda)$ lying in
pairs in the complex plane. Consequently the existence of an odd number of
normalizable zero modes of the 5-dim.($D=5$) massive Dirac operator is
equivalent to a fermionic level exchange phenomenon, level ``circling'', under
continuous topologically nontrivial deformations of the external gauge field.
More generally global anomalies are a manifestation of fermionic level
``circling'' in any $SP(2n)$ gauge theory with an odd number of massive
fermions in the spinor representation and arbitrary Yukawa couplings.


title: Using `Invisible' Decay Modes as Probes of Z' Couplings

abstract:
  We explore the possibility that $Z'$ couplings can be probed using decay
modes which involve neutrinos once Standard Model backgrounds are directly
determined by the data itself. For some models, sufficient statistics are
available at either the SSC or LHC to render these modes useful for coupling
determinations, provided the mass of the $Z'$ is not much larger than 1 TeV, if
we assume other new physics background sources are absent.


title: On R-Parity Violation at $e^+ e^-$ Colliders

abstract:
  I discuss several promising $R$-parity violating processes at $e^+e^-$
colliders.