title: Towards a Model Independent Treatment of Future Solar Neutrino Data

abstract:
  Possibilities of a model independent treatment of the data from future
real-time solar neutrino experiments (SNO, Super-Kamiokande and others) are
discussed. It is shown that in the general case of transitions of the initial
solar $\nu_e$'s into $\nu_\mu$ and/or $\nu_\tau$ the total flux of initial
$^8\mathrm{B}$ neutrinos and the $\nu_e$ survival probability can be determined
directly from the experimental data. Relations between observable quantities
are derived, which, if confronted with the experimental data, would allow to
reveal the presence of sterile neutrinos in the solar neutrino flux on the
earth. Neutrino transitions due to spin and resonant spin-flavour precession in
the magnetic field of the sun are shortly discussed.


title: Revenge of the One-Family Technicolor Models

abstract:
  We describe how isospin splitting and techniquark-technilepton splitting in
one-family technicolor models can reduce the predicted value of the electroweak
radiative correction parameter S, without making a large contribution to the T
parameter.


title: Effect of CP-Odd Planck Scale Induced Operators on the Majoron Scale

abstract: Definitions of the control sequences included, but no other changes.


title: Heavy Quark Fragmentation to Polarised Quarkonium

abstract:
  We calculate the polarisation of $\psi$'s and $\Upsilon$'s produced by the
fragmentation of heavy quarks. We find that fragmentation to transversely
aligned quarkonium is slightly enhanced relative to longitudinally polarised.
This net alignment corresponds to a $\sim 5\%$ asymmetry in the angular
distribution of leptons produced in the subsequent decay of the quarkonium. We
point out that the leading gluon contribution to $\psi$ and $\Upsilon$
production arises from the evolution of the charm quark fragmentation function,
rather than from direct gluon fragmentation.


title:
Degree Scale Microwave Anisotropies in NonGaussian Theories of Cosmic
  Structure Formation

abstract:
  The COBE satellite's maps of the cosmic microwave background (CMB) anisotropy
do not have the resolution to discriminate between theories of cosmic structure
formation based on inflation, and those based on field ordering following a
symmetry breaking phase transition. For this purpose it is critical to resolve
the CMB anisotropy on degree scales. In this paper we report on detailed
calculations of the degree scale anisotropies predicted in the global string,
monopole, texture and nontopological texture scenarios of structure formation,
emphasising their distinct character from those predicted by inflation, and
commenting on the prospects of their detection in the near future.


title: Phenomenological Implications of Supersymmetry Breaking by the Dilaton

abstract:
  We investigate the low energy properties of string vacua with spontaneously
broken $N=1$ supersymmetry by a dilaton $F$-term. As a consequence of the
universal couplings of the dilaton, the supersymmetric mass spectrum is
determined in terms of only three independent parameters and more constrained
than in the minimal supersymmetric Standard Model. For a $\mu$-term induced by
the \K\ potential the parameter space becomes two-dimensional; in the allowed
regions of this parameter space we find that most supersymmetric particles are
determined solely by the gluino mass. The Higgs is rather light and the
top-quark mass always lower than 180 GeV.


title: Semiclassical Scattering in Yang-Mills Theory

abstract:
  A classical solution to the Yang-Mills theory is given a new semiclassical
interpretation. The boundary value problem on a complex time contour which
arises from the semiclassical approximation to multiparticle scattering
amplitudes is reviewed and applied to the case of Yang- Mills theory. The
solution describes a classically for- bidden transition between states with a
large average number of particles in the limit $g\rightarrow 0$. It dominates a
transition probability with a semiclassical suppression factor equal to twice
the action of the well- known BPST instanton. Hence, it is relevant to the pro-
blem of high energy tunnelling. It describes transitions of unit topological
charge for an appropriate time contour. Therefore, it may have a direct
interpretation in terms of fermion number violating processes in electroweak
theory. The solution describes a transition between an initial state with
parametrically fewer particles than the final state. Thus, it may be relevant
to the study of semiclassical initial state corrections in the limit of a small
number of initial particles. The implications of these results for
multiparticle production in electroweak theory are also discussed.


title: Axion detection in the milli-eV mass range

abstract:
  We propose an experimental scheme to search for galactic halo axions with
mass $m_a \sim 10^{-3}$eV, which is above the range accessible with cavity
techniques. The detector consists of a large number of parallel superconducting
wires embedded in a material transparent to microwave radiation. The wires
carry a current configuration which produces a static, inhomogeneous magnetic
field $\vec{B}_0(\vec{x})$ within the detector volume. Axions which enter this
volume may convert to photons. We discuss the feasibility of the detector and
its sensitivity.


title: Neutrino Cosmology and Limits on Extended Technicolor

abstract:
  Using Big Bang Nucleosynthesis limits on the number of light neutrinos we
derive a cosmological lower bound of $\approx 2$ TeV on the scale of extended
technicolor interactions (or any other new interactions) for the third family
in models where heavy gauge bosons couple to both left and right-handed
neutrinos.


title: Successive Combination Jet Algorithm For Hadron Collisions

abstract:
  Jet finding algorithms, as they are used in $e^+ e^-$ and hadron collisions,
are reviewed and compared. It is suggested that a successive combination style
algorithm, similar to that used in $e^+ e^-$ physics, might be useful also in
hadron collisions, where cone style algorithms have been used previously.


title:
The Semileptonic Decays $D\to \pi(\rho) e \nu$ and $B\to \pi (\rho) e
  \nu$ from QCD Sum Rules

abstract:
  We investigate the semileptonic decays of B and D mesons into $\pi$ and
$\rho$ mesons, respectively, by means of QCD sum rules. We find that for the
vector formfactors involved the pole dominance hypothesis is valid to good
accuracy with pole masses in the expected range. Pole dominance, however, does
not apply to the axial formfactors which results in specific predictions for
the predominant polarization of the $\rho$ meson and the shape of the lepton
spectrum. For the total decay rates we find $\Gamma (\bar B^0 \to \pi^+ e^-
\bar\nu) = (5.1\pm 1.1)\,|V_{ub}|^2\, 10^{12}\,{\rm s^{-1}}$, $\Gamma ( D^0 \to
\pi^- e^+ \nu) = (8.0\pm 1.7)\,|V_{cd}|^2\, 10^{10}\,{\rm s^{-1}}$, $\Gamma
(\bar B^0 \to \rho^+ e^- \bar\nu) = (1.2\pm 0.4\,)\,|V_{ub}|^2\, 10^{13}\,{\rm
s^{-1}}$ and $\Gamma (D^0 \to \rho^- e^+\nu) = (2.4\pm 0.7)\,|V_{cd}|^2\,
10^{9}\,{\rm s^{-1}}$.


title: A Fermion Mass Matrix Ansatz for the Fipped SU(5) Model

abstract:
  A fermion mass matrix ansatz is proposed in the context of Grand Unified
Supersymmetric Theories (GUTs). The fermion mass matrices are evolved down to
the electroweak scale by solving the renormalization group equations for the
gauge and Yukawa couplings. Eight inputs are introduced at the GUT scale to
predict the 13 arbitrary parameters of the Standard model. The constraints
imposed by the charged fermion data are used to make predictions in the
neutrino sector. In particular, the neutrino mass matrix is worked out in the
case of the flipped SU(5) model and it is found that the
  {\it generalized } see-saw mechanism which occurs naturally in this model can
provide a solution to the solar neutrino puzzle and give a sufficiently large
$\nu_{\tau}$ mass to contribute as a hot dark matter component as indicated by
the recent COBE data.


title:
Instanton-induced contributions to structure functions of deep inelastic
  scattering

abstract:
  We identify and calculate the instanton-induced contributions to deep
inelastic scattering which correspond to nonperturbative exponential
corrections to the coefficient functions in front of parton distributions of
the leading twist.


title:
Leading Electroweak Corrections to the Production of Heavy Top Quarks at
  Hadron Colliders

abstract:
  We calculate the electroweak corrections of the order $O({m_t^2\over v^2})$
to the QCD production of $t\bar{t}$ pairs via $q+qbar->t+tbar$ at hadron
colliders and show that these corrections to the total production rate are
small. This correction can be characterized as increasing the cross section
most near the threshold region, where top quark signals are important, while
the corrections become negative at higher $t\bar{t}$ energies where the top
quark is a background for heavy Higgs boson searches or investigations
involving the strongly interacting longitudinal $W$ system. The polarization of
the $t\bar t$ pair is also discussed, including the effect that this has on
proposed techniques for measuring the the top quark mass.


title: Can Electro-Weak $\h$-Term be Observable ?

abstract:
  We rederive and discuss the result of the previous paper that in the standard
model $\theta$-term related to $W$-boson field can not be induced by weak
instantons. This follows from the existence of the fermion zero mode in the
instanton field even when Yukawa couplings are switched on and there are no
massless particles. We consider the new index theorem connecting the
topological charge of the weak gauge field with the number of fermion zero
modes of a certain differential operator which depends not only on gauge but
also on Higgs fields. The possible generalizations of the standard model are
discussed which lead to nonvanishing weak $\theta$-term. In $SU(2)_L \times
SU(2)_R$ model the $\theta$ dependence of the vacuum energy is computed.


title:
Constraints on CP violation in the Higgs sector from the $\rho$
  parameter

abstract:
  We discuss the relation between the CP symmetry and the custodial $SU(2)$
symmetry in the Higgs sector. In particular, we show that CP violation in the
Higgs-gauge sector is allowed only if the custodial $SU(2)$ symmetry is broken.
We exploit these facts to constrain CP violation using the experimental bounds
on $\rho-1$. CP nonconservation in the Higgs-fermion interactions can also be
constrained in a similar way although a possible exception is pointed out.


title:
$\O(\GF^2\Mt^4)$ Electroweak Radiative Corrections to the $\PZ\Pb\Pbbar$
  Vertex

abstract:
  The leading heavy-top two-loop corrections to the \Zbb~vertex are determined
from a direct evaluation of the corresponding Feynman diagrams in the large
\Mt~limit. %The calculation is done in the naive %dimensional regularization
scheme with anticommuting $\ga_5$. The leading one-loop top-mass effect is
enhanced by $[1+\GF\Mt^2(9-\pi^2/3)/(8\pi^2\sqrt{2})]$. Our calculation
confirms a recent result of Barbieri et al.


title: Baryon Asymmetry of the Universe in the Minimal Standard Model

abstract:
  We calculate the baryon asymmetry of the Universe which would arise during a
first order electroweak phase transition due to minimal standard model
processes. It agrees in sign and magnitude with the observed baryonic excess,
for resonable KM parameters and m$_t$ in the expected range, and plausible
values of bubble velocity and other high temperature effects. A detailed
version of this work (77pp) is being simultaneously submitted to the net. A
shortened version of this recently appeared in Phys. Rev. Lett. {\bf 70}, 2833,
1993.


title: Baryon Asymmetry of the Universe in the Standard Model

abstract:
  We study the interactions of quarks and antiquarks with the changing Higgs
field during the electroweak phase transition, including quantum mechanical and
some thermal effects, with the only source of CP violation being the known CKM
phase. The magnitude and sign of the predicted BAU agrees with the observed
value, with moderately optimistic assumptions about the dynamics of the phase
transition. At present uncertainties related to the dynamics of the ew phase
transition and the oversimplifications of our treatment are too great to decide
whether or not this is the correct explanation for the presence of remnant
matter in our universe, however the present work makes it clear that the
minimal standard model cannot be discounted as a contender for explaining this
phenomenon.


title:
On the Treatment of Neutrino Oscillations Without Resort to Weak
  Eigenstates

abstract:
  We discuss neutrino oscillations in the framework of the quantum field theory
without introducing the concept of neutrino weak eigenstates. The external
particles are described by wave packets and the different mass eigenstate
neutrinos propagate between the production and detection interactions, which
are macroscopically localized in space-time. The time-averaged cross section,
which is the measurable quantity in the usual experimental setting, is
calculated. It is shown that only in the extremely relativistic limit the usual
quantum mechanical oscillation probability can be factored out of the cross
section.


title: Finding the Leptonic $WW$ Decay Mode of a Heavy Higgs Boson

abstract:
  We reanalyze the extraction of the heavy Higgs boson signal $H\rightarrow
W^+W^-\rightarrow \bar\ell\nu,\ell\bar\nu$ $(\ell=e\hbox{ or }\mu)$ from the
Standard Model background at hadron supercolliders, taking into account revised
estimates of the top quark background. With new acceptance criteria the
detection of the signal remains viable. Requiring a forward jet-tag, a central
jet-veto, and a large relative transverse momentum of the two charged leptons
yields $S/\sqrt B>6$ for one year of running at the SSC or LHC.


title: Topologically Stable Electroweak Flux Tube

abstract:
  We show that for a large range of parameters in a $SU(2)_L\times U(1)$
electroweak theory with two Higgs doublets there may exist classically stable
flux tubes of Z boson magnetic field. In a limit of an extra global $\tilde
U(1)$ symmetry, these flux-tubes become topologically stable. These results are
automatically valid even if $\tilde U(1)$ is gauged.


title: QCD Corrections to Production of Higgs Pseudoscalars

abstract:
  Models of electroweak symmetry breaking with more than a single doublet of
Higgs scalars contain a neutral pseudoscalar boson. The production of such a
pseudoscalar in hadron collisions proceeds primarily via gluon fusion through a
top-quark loop (except for those models in which the pseudoscalar coupling to
bottom quarks is strongly enhanced). We compute the QCD corrections to this
process in the heavy-quark limit, using an effective Lagrangian derived from
the axial anomaly.


title: Multi-W(Z) Production in High-Energy Collisions?

abstract:
  There exists the possibility that the cross-section for the nonperturbative
production of many, ${\cal O}(\alpha_W^{-1} \simeq 30 )$, weak gauge bosons may
be as large as ${\cal O}(100\ {\rm pb}\ -\ 10\ \mu$b$)$ above a parton-parton
center-of-mass threshold in the range $2.4\ -\ 30$ TeV. We review the
theoretical considerations which lead to this suggestion and outline its
phenomenological implications, both for present cosmic ray as well as for
future collider experiments. (Lecture presented at the 4th Hellenic School on
Elementary Particle Physics, September 2-20, 1992, Corfu, Greece) (Figures not
included, available by ordinary mail)


title: Hyperons as Solitons in Chiral Quark Model

abstract:
  The paper describes the quantization of the SU(3) smibosonized
Nambu-Jona-Lasinio model and results for mass splittings, including isospin
splittings, and axial couplings. The agreement with the data is surprisingly
good.


title:
Squark Contributions to Higgs Boson Masses in the Next--to--Minimal
  Supersymmetric Standard Model

abstract:
  Within the context of an effective potential formalism we calculate the
contribution to Higgs boson masses in the next--to--minimal supersymmetric
standard model from squark loops. We then supplement a previously performed
renormalisation group analysis of the Higgs sector of this model with these
results in order to determine the shift in the bound on the lightest CP-even
Higgs boson mass as a result of squark effects. The improved bound on the
lightest neutral CP-even Higgs boson mass, including squark contributions, is
$m_h \leq 146 \ \ (139, 149)$ GeV for $m_t = 90 \ \ (140, 190)$ GeV. For $m_t =
190$ GeV squark effects contribute 23 GeV to the bound, with smaller
contributions for small $m_t$ values.


title: Spin Structure of the Pion in a Light-Cone Representation

abstract:
  The spin structure of the pion is discussed by transforming the wave function
for the pion in the naive quark model into a light-cone representation. It is
shown that there are higher helicity ($\lambda_{1}+\lambda_{2}=\pm1$) states in
the full light-cone wave function for the pion besides the ordinary helicity
($\lambda_{1}+\lambda_{2}=0$) component wave functions as a consequence from
the Melosh rotation relating spin states in light-front dynamics and those in
instant-form dynamics. Some low energy properties of the pion, such as the
electromagnetic form factor, the charged mean square radius, and the weak decay
constant, could be interrelated in this representation with reasonable
parameters.


title: Photon neutrino scattering

abstract:
  The cross section for photon neutrino scattering is calculated in the
standard model assuming that the neutrino is massless and that the center of
mass energy is small compared to any charged lepton mass. Although the
scattered photons can acquire a (parity violating) circular polarization of
order unity, the cross section in this limit is highly suppressed.


title: Electrweak Z-string And $\tan\beta$

abstract:
  In the standard model with two Higgs doublets it is shown that the existence
of the electroweak Z-string in general requires the same characteristic length
for the two Higgs fields as well as a specific ratio of the two Higgs vacuum
expectation values, i.e. $\tan\beta$. This ratio can be determined in terms of
the couplings in the Higgs potential. Some remarks on the supersymmetric case
are given. \noindent (Talk presented at SUSY '93, March 29-April 1st,
Northeastern University, Boston, MA 02115, USA.)


title: In Search for (QUANTUM) Color Transparency

abstract:
  Color transparency (CT) is an effect of suppression of nuclear shadowing of
hard reactions, closely related to the color screening. A brief review of
theoretical development and experimental search for CT, failed and successful,
are presented. A special emphasis is made on a quantum-mechanical nature of CT,
as opposed to a wide spread erroneousclassical treatment of this phenomenon.
The typical predictions of the classical approach, all contradicting quantum
mechanics are:
  - factorization of cross section of hard reactions on a nucleus;\\
  - "nuclear transparency", a normalized ratio of nuclear to nucleon cross
sections, cannot exceed one;\\
  - the larger is a radius of a hadron, the stronger it attenuates in a
nucleus;\\
  - the higher is the energy of hadrons participating in a hard reaction, the
less is the nuclear attenuation;\\
  - due to CT hard processes provide a better opportunity to study
Fermi-momentum distribution, than soft reactions; etc. (Talk presented at
XXVIII Rencontres de Moriond, March 1993)


title: Supersymmetric Signals in $e^-e^-$ Collisions

abstract:
  We consider the production and decay of selectrons and charginos in $e^-e^-$
collisions. The advantage over usual $e^+e^-$ collisions is the very low level
of standard model backgrounds which should make the discovery of selectrons or
charginos relatively straightforward. The use of polarized beams provides an
additional powerful tool to determine the supersymmetry parameters.


title:
Phenomenological Implications of the m_t RGE Fixed Point for SUSY Higgs
  Boson Searches

abstract:
  In minimal SUSY-GUT models with $M_{SUSY}\alt 1$ TeV, the renormalization
group equations have a solution dominated by the infrared fixed point of the
top Yukawa coupling. This fixed point predicts $m_t\simeq (200\; {\rm GeV})\sin
\beta $; combined with the LEP results it excludes $m_t\alt 130$ GeV. For $m_t$
in the range 130--160 GeV, it predicts that the lightest scalar $h$ has mass
60--85 GeV (detectable at LEP\,II). At SSC/LHC, each of the five scalars $h$,
$H$, $A$, $H^{\pm }$ may be detectable, but not all of them together; in one
parameter region none would be detectable.


title:
$b \rightarrow s \gamma$ and $B_s \rightarrow \mu^+ \mu^-$ in Extended
  Technicolor Models

abstract:
  The rates of the rare flavor-changing processes, $b \rightarrow s \gamma$ and
$B_s \rightarrow \mu^+ \mu^-$ are estimated in extended technicolor models with
and without a GIM mechanism. We find the $b \rightarrow s \gamma$ rate in ETC
models with a GIM mechanism to be at most slightly larger than the standard
model rate, whereas there is no significant extra model-independent
contribution in other ETC scenarios.
  In the case of $B_s \rightarrow \mu^+ \mu^-$, ETC models with a GIM mechanism
can yield a rate up to two orders of magnitude bigger than that of the standard
model, whereas generic ETC scenarios are likely to give a rate which is about
an order of magnitude bigger than that of the standard model.


title: CP Violation and Leptogenesis

abstract:
  Recently a model of chaotic inflation was proposed, where the right handed
sneutrinos drive the baryogenesis. We study some of the details of the model,
particularly the aspect of CP violation, and determine the number of right
handed sneutrinos required for the viability of such models.


title:
Two Dimensional Field Theory Description of Disoriented Chiral
  Condensate

abstract:
  We consider the effective $1+1$-dimensional chiral theory describing
fluctuations of the order parameter of the Disoriented Chiral Condensate (DCC)
which can be formed in the central rapidity region in a relativistic
nucleus-nucleus or nucleon-nucleon collisions at high energy. Using
$1+1$-dimensional reduction of QCD at high energies and assuming spin
polarization of DDC one can find the Wess-Zumino-Novikov-Witten (WZNW) model at
level $k=3$ as the effective chiral theory for the one-dimensional DDC. Some
possible phenomenological consequences are briefly discussed.


title: Effective Lagrangians and Triple Boson Couplings

abstract:
  I review the use of effective lagrangians in describing the physics beyond
the standard model, several theoretical and practical aspects are discussed. It
is argued that the only situations where new physics can be observed
corresponds to cases where the standard model cntributions are extremely
suppressed and where high quality data is avaliable.


title: Magnetic Moments of the Baryon Decuplet in a Relativistic Quark Model

abstract:
  The magnetic moments of the baryon decuplet are calculated in a relativistic
constituent quark model using the light-front formalism. Of particular interest
are the magnetic moments of the $\Omega^-$ and $\Delta^{++}$ for which new
recent experimental measurements are available. Our calculation for the
magnetic moment ratio $\mu(\Delta^{++})/\mu(p)$ is in excellent agreement with
the experimental ratio, while our ratio $\mu(\Omega^-)/\mu(\Lambda^0)$ is
slightly higher than the experimental ratio.


title:
A Possible Way of Connecting the Grassmann Variables and the Number of
  Generation

abstract:
  We construct a Left-Right symmetric model in which the number of generation
is related to Grassmann variables. We introduce two sets of complex Grassmann
variables ($\theta^1_q$,$\theta^2_q$), ($\theta^1_l$, $\theta ^2_l$) and
associate each variable with left- and right-handed quark and lepton fields,
respectively. Expanding quark and lepton fields in powers of the Grassmann
variables, we find that there are exactly three generations of quarks and
leptons. Integrating out the Grassmann variables, we obtain phenomenologically
acceptable fermion mass matrices.


title: On "Electromagnetic Potential Vectors and Spontaneous Symmetry Breaking"

abstract:
  The appearance of terms, which are analogous to ones required for symmetry
breaking, in Lagrangian of Ref. [1] is shown to be caused by gauge invariance
of quantum electrodynamics (QED) and by inaccuracy of the cited author in the
choice of canonical variables. These terms do not have physical significance
within modern quantum electrodynamics. PACS: 03.50.De, 04.20.Cv, 04.20.Fy,
11.10.Ef.


title: QED-Induced Rapidity-Gap Events at the Z Peak

abstract:
  We study rapidity-gap events in $e^+e^-$ annihilation at the Z boson peak
initiated by the emission of a virtual photon. This mechanism is suppressed by
the QED coupling constant, but it is enhanced due to a large propagator term
from the virtual photon. For typical kinematics, we find a smaller event rate
than analogous QCD type gap events. In the small jet-pair invariant mass limit,
the QED type events follow a $1+\cos^2\theta$ distribution in the jet-pair
scattering angle, instead of the $\sin^2\theta$ distribution of the QCD case.


title: Renormalizabilty of TH Heavy Quark Effective Theory

abstract:
  We show that the Heavy Quark Effective Theory is renormalizable
perturbatively. We also show that there exist renormalization schemes in which
the infinite quark mass limit of any QCD Green function is exactly given by the
corresponding Green function of the Heavy Quark Effective Theory. All this is
accomplished while preserving BRS invariance.


title: Chiral Perturbation Theory

abstract:
  The basic ideas and power counting rules of chiral perturbation theory are
discussed. The formalism of velocity dependent fields for baryons, and for
hadrons containing a heavy quark, is explained. (Invited Talk, 1993 QCD
Rencontres de Moriond)


title:
Observation of High Energy Quark-Antiquark Elastic Scattering with
  Mesonic Exchange

abstract:
  We studied the high energy quark anti-quark elastic scattering with an
exchange of a mesonic state in the $t$ channel with $-t/\Lambda_{QCD}^{2} \gg
1$. Two methods are proposed to eliminate the strong background from bare
pomeron, reggized gluon and odderon exchange. The feasibility of measuring
mesonic reggeon exchange is discussed.


title:
Quasipotential in the Fourth Order of Perturbation Theory. Unequal mass
  case

abstract:
  The quasipotential in the fourth order of perturbation theory is calculated
in the Coulomb gauge for the unequal mass particles. It could be used for the
future calculations of energy spectra in two-body systems.


title: Semiclassical transition in \phi^4 theory

abstract:
  We have shown an example of semiclassical transition in $\phi^{4}$ theory
with positive coupling constant. This process can be described by the classical
$O(4)$-invariant solution, considered on a contour in the complex time plane.
The transition is technically analogous to the one-instanton transition in the
electroweak model. It is suppressed by the factor $\exp(-2S_{0})$, where
$S_{0}$ is Lipatov instanton action. This process describes a semiclassical
transition between two coherent states with much smaller number of particles in
the initial state than in the final state. Therefore, it could be relevant to
the problem of calculation of amplitudes for multiparticle production in
$\phi^4$-type models.


title:
The Energy Density of a Gas of Photons Surrounding a Spherical Mass $M$
  at a Non-Zero Temperature

abstract:
  The equations determining the energy density $\rho$ of a gas of photons in
thermodynamic equilibrium with a spherical mass $M$ at a non-zero temperature
$T_s>0$ is derived from Einstein's equations.
  It is found that for large $r$, $\rho \sim 1/r^2$ where the proportionality
constant is a {\it fundamental constant\/} and is the same for all spherical
masses at all temperatures.


title:
The Asymptotic Form of the Energy Density of Weakly Interacting
  Particles in a Static, Spherical Geometry

abstract:
  The asymptotic form of the energy density for a gas of particles surrounding
a sphere of mass $M$ and radius $R$ is studied using Einstein's equations. It
is shown that if the pressure of the gas $p$ varies linearly with the energy
density $\rho$ for small $\rho$, then $\rho\sim 1/r^2$ for large $r$.


title:
The Subleading Isgur-Wise Form Factor $\xi_3(v\cdot v')$ and its
  Implications for the Decays $\bar B\to D^{(*)}\ell\,\bar\nu$

abstract:
  We calculate, in the framework of QCD sum rules and to next-to-leading order
in perturbation theory, the universal function $\xi_3(v\cdot v')$ which appears
at order $1/m_Q$ in the heavy quark expansion of meson weak decay form factors.
We find that radiative corrections of order $\alpha_s$ are very important. Over
the kinematic range accessible in semileptonic decays, $\xi_3(v\cdot v')$ is
proportional to the leading-order Isgur-Wise function $\xi(v\cdot v')$ to very
good accuracy. Taking into account all sources of uncertainty, we estimate
$\xi_3/\xi=(0.6\pm 0.2)$. This reduces the theoretical uncertainty in the
extraction of $|\,V_{cb}|$ from $\bar B\to D\,\ell\, \bar\nu$ transitions. A
measurement of the form factor ratio $A_2/A_1$ in $\bar B\to D^*\ell\,\bar\nu$
decays can be used to test our prediction.


title: QCD Matching Conditions at Thresholds

abstract:
  The use of MS-like renormalization schemes in QCD requires an implementation
of nontrivial matching conditions across thresholds, a fact often overlooked in
the literature. We shortly review the use of these matching conditions in QCD
and check explicitly that the prediction for $\alpha_s(M_Z)$, obtained by
running the strong coupling constant from the $M_\tau$ scale, does not
substantially depend on the exact value of the matching point chosen in
crossing the $b$-quark threshold when the appropriate matching conditions are
taken into account.


title: Analysis of Data on Polarized Lepton-Nucleon Scattering

abstract:
  We re-analyze data on deep inelastic polarized lepton-nucleon scattering,
with particular attention to testing the Bjorken sum rule and estimating the
quark contributions to the nucleon spin. Since only structure function data at
fixed $Q^2$ can be used to test sum rules, we use E142 asymmetry measurements
and unpolarized structure function data to extract $g_1^n$ at fixed $Q^2$ = 2
GeV$^2$. When higher-twist effects, which are important at low $Q^2$, are
included, both the E142 and SMC data are compatible with the Bjorken sum rule
within one standard deviation. Assuming validity of the Bjorken sum rule, we
estimate the quark contributions to the nucleon spin, finding that their total
net contribution is small, with the strange quark contribution non-zero and
negative. The quark spin content of the nucleon spin is in agreement with
Skyrme model.


title: Axions, Monopoles and Cosmic String

abstract:
  We are discussing some aspects of the magnetic monopoles and cosmic strings
interactions with axion domain walss and membranes. The monopole moving through
an axion domain wall is transformed into a monopole bag - the state with a dyon
quantum number, but smaller mass. In the case of an axion membrane the passing
monopole excites the chiral charged state at the membrane boundary. It will be
shown that if cosmic string intersects an axion domain wall there will be
$\theta = \pi$, i.e. maximal $CP$-violation inside the string. Strings carrying
the flux of the $Z$-boson field become the sources of the baryon charge
nonconservation. The symbiosis of the two pictures - monopole passing through
an axion domain wall and string intersecting it - is the case of the
interaction between an axion domain wall and a Nambu electroweak string
carrying $SU(2)_{L}$ monopoles at the ends.


title: Induced Charge of Neutrinos in a Medium

abstract:
  Neutrinos can polarize a medium due to their weak interaction. This can
manifest itself as an effective induced charge of the neutrino. We show how it
is related to the Debye screening length in a plasma, first using the results
of the 1-loop calculation of the neutrino electromagnetic vertex and then in
general to all orders in $e$ and to leading order in the Fermi coupling. We
also discuss how the results are modified if the neutrinos have mass -- either
Dirac or Majorana type.


title:
Measuring transversity densities in singly polarized hadron-hadron and
  lepton-hadron collisions

abstract:
  We show how the transverse polarization of a quark initiating a jet can be
probed by the azimuthal distribution of two hadrons (of large $z$) in the jet.
This permits a twist 2 asymmetry in hard processes when only one of the initial
particles is polarized transversely. Applications to hadron-hadron and
lepton-hadron scattering are discussed.


title:
Supersymmetric QCD corrections to quark pair production in e+ e-
  annihilation

abstract:
  We calculate supersymmetric QCD corrections (squark/gluino loops) to quark
pair production in e+ e- annihilation, allowing for mixing between left- and
right-handed squarks and taking into account the effects of nonzero quark
masses. Corrections to the Z boson partial widths are generally small and
positive, except in the case of large b-squark mixing, where they become
negative. At high-energy e+ e- colliders, larger corrections to the total cross
sections are possible. Corrections to forward-backward asymmetries are
negligible except possibly for top quarks, where they are sensitive to t-squark
mixing. We also comment on the possibility that the gluino mass is only a few
GeV.


title:
Nucleon Mass Corrections to the $p \leftrightarrow n$ Rates During Big
  Bang Nucleosynthesis

abstract:
  The thermal rates for converting neutrons to protons, and vice versa, are
calculated, including corrections of order 1 MeV divided by a nucleon mass. The
results imply that the primodial helium abundance predicted for big bang
nucleosynthesis has been systematically underestimated by about $\delta Y_4 =
0.0012$, i.e., $\delta Y_4 / Y_4 \approx .005$.


title: Symmetric Textures

abstract:
  I present an algorithm in the search for symmetric textures in the quark
Yukawa matrices. This is based on a talk at the Coral Gables conference in
January 1993. I include the macro tables2.tex for making tables, and use the
Santa Barbara jnl and reforder macros.


title: Total and Jet Photoproduction Cross Sections at HERA

abstract:
  We show that the recent measurements of the total photoproduction cross
section at HERA energies [1] are in agreement with our earlier prediction based
on high-energy hadronic structure of the photon in the QCD minijet-type model
[2]. We discuss an improved calculation of the photoproduction cross section,
in which the soft part, motivated by the Regge theory, is taken to be
energy-dependent and the semi-hard hadronic part is carefully eikonalized to
take into account for the multiple scatterings and to include the appropriate
hadronic probability of the photon [3]. We show that the extrapolation of our
cross section to ultra-high energies, of relevance to the cosmic ray physics,
gives significant contribution to the ``conventional'' value, but cannot
account for the anomalous muon content observed in the cosmic ray air-showers
associated with astrophysical point sources [4]. (invited talk presented at QCD
Recontres de Moriond 1993)


title:
QCD Corrections to Hadronic $W\gamma$ Production with Non-standard
  $WW\gamma$ Couplings

abstract:
  The process $p \pbar \rightarrow W^{\pm}\gamma + X \rightarrow \ell^\pm \nu
\gamma + X$ is calculated to ${\cal O}(\alpha_s)$ for general $CP$ conserving
$WW\gamma$ couplings. At the Tevatron center of mass energy, the QCD
corrections to $W\gamma$ production are modest, and the Born and inclusive
${\cal O}(\alpha_s)$ cross sections have similar sensitivities to the effects
of anomalous couplings. At supercollider energies, the inclusive QCD
corrections are large at high photon transverse momenta, reducing the
sensitivity to non-standard $WW\gamma$ couplings by up to a factor~2. The size
of the QCD corrections can be reduced significantly, and a large fraction of
the sensitivity lost can be regained, if a jet veto is imposed.


title: Heavy Quark Fragmentation to Baryons Containing Two Heavy Quarks

abstract:
  We discuss the fragmentation of a heavy quark to a baryon containing two
heavy quarks of mass $m_Q\gg\Lambda_{\rm QCD}$. In this limit the heavy quarks
first combine perturbatively into a compact diquark with a radius small
compared to $1/\Lambda_{\rm QCD}$, which interacts with the light hadronic
degrees of freedom exactly as does a heavy antiquark. The subsequent evolution
of this $QQ$ diquark to a $QQq$ baryon is identical to the fragmentation of a
heavy antiquark to a meson. We apply this analysis to the production of baryons
of the form $ccq$, $bbq$, and $bcq$.


title: Search for Physics Beyond the Standard Model

abstract:
  We survey some recent ideas and progress in looking for particle physics
beyond the Standard Model, connected by the theme of Supersymmetry (SUSY). We
review the success of SUSY-GUT models, the expected experimental signatures and
present limits on SUSY partner particles, and Higgs phenomenology in the
minimal SUSY model.


title: Natural Color Transparency in High Energy (p,pp) Reactions

abstract:
  New parameter free calculations including a variety of necessary kinematic
and dynamic effects show that the results of BNL $(p,2p)$ measurements are
consistent with the expectations of color transparency.


title: Rigid String From QCD Lagrangian

abstract:
  Starting from the 4-dimensional gluodynamics, we discuss the statistical
ensemble of torons ( the toron is a self-dual solution with fractional
topological number; it can be understood as a point defect) which interact
strongly. It is shown that the effective Lagrangian describing this statistical
ensemble possesses the fourth derivative kinetic term and leads to the area law
for the Wilson loop. Besides that we derive the effective string action
containing the rigid (extrinsic curvature) term as a consequence of the fourth
derivative action.


title: Proton structure function at small Q^2

abstract:
  A fit is made to the data for the proton structure function up to Q^2=10
GeV^2, including the real gamma p total cross-section. It is economical and
simple, and its form is motivated by physical principles. It is extrapolated
down to very small values of x. Data for the ratio (nu W_2^n/nu W_2^p) are also
fitted. A FORTRAN program for the fit to (nu W_2^p) is available by email on
request Figure 5 from the original version has been deleted.


title: A Dynamical Resolution of the Sigma Term Puzzle

abstract:
  We propose a resolution of the puzzle posed by the discrepancy between the
pion-nucleon sigma term inferred from pion-nucleon scattering, and that deduced
from baryon mass splittings using the Zweig rule. We show that there is a
significant hypercharge-dependent dynamical contribution to baryon masses, not
hitherto included in the analysis, which may be estimated using the scale Ward
identity, and computed by solution of the Schwinger-Dyson equation for the
quark self-energy. We find that the discrepancy is completely resolved without
the need for any Zweig rule violation.


title: On Gauge Invariance of Breit-Wigner Propagators

abstract:
  We present an approach to bosonic ($Z^0, W^{\pm}$) as well as fermionic
(top-quark) Breit-Wigner propagators which is consistent with gauge invariance
arguments. In particular, for the $Z^0$-boson propagator we extend previous
analyses and show that the part proportional to $k_{\mu} k_{\nu}/M^2$ must be
modified near the resonance. We derive a mass shift which agrees with results
obtained elsewhere by different methods. The modified form of a resonant heavy
fermion propagator is also given.


title:
Mapping the x dependence of the axial anomaly in polarised deep
  inelastic scattering

abstract:
  We discuss the role of the U(1) axial anomaly in the spin structure functions
of the nucleon, with particular emphasis on how one might determine its x
dependence in present and future deep inelastic scattering experiments. We
focus on the C-odd spin structure function g3 and also the deuteron structure
function g1^d.


title: Gauge symmetry and the EMC spin effect

abstract:
  We emphasise the EMC spin effect as a problem of symmetry and discuss the
renormalisation of the $C=+1$ axial tensor operators. This involves the
generalisation of the Adler-Bell-Jackiw anomaly to each of these operators. We
find that the contribution of the axial anomaly to the spin dependent structure
function $g_1 (x, Q^2)$ scales at $O(\alpha_s)$. This means that the anomaly
can be a large $x$ effect in $g_1$. Finally we discuss the jet signature of the
anomaly.


title: Direct CP Violation in $K_L\to\pi^+\pi^-\gamma$

abstract:
  CP violation due to interference between $K_L$ and $K_S$ decays into $\pi
^+\pi^-\gamma$ is analyzed in the Standard Model. The CP-violating parameter
$\epsilon'_{+- \gamma}$, which is the difference between $\eta_{+-\gamma}$ and
$\eta_{+-}$, receives dominant contributions from $K^0-\bar{K}^0$ mixing and
the gluon penguin diagram; its magnitude is calculated to be $10^{-2}\epsilon$
at a typical region of the Dalitz plot. Genuine direct CP violation in
$K_L\to\pi^+ \pi^-\gamma$ decay originating from the electromagnetic penguin
diagram is of order $10^{-4}\epsilon$.


title:
Evidence for Observation of Color Transparency in Proton Nucleus
  Collisions

abstract:
  We introduce a data analysis procedure for color transparency experiments
which is considerably less model dependent than the transparency ratio method.
The new method is based on fitting the shape of the A dependence of the nuclear
cross section at fixed momentum transfer to determine the effective attenuation
cross section for hadrons propagating through the nucleus. The hard scattering
cross section is then determined directly from the data. We apply this
procedure to the Brookhaven experiment of Carroll et al and find that it
clearly shows color transparency: the effective attenuation cross section in
events with momentum transfer $Q^2$ is approximately $40\ mb\ (2.2\
GeV^2/Q^2)$. The fit to the data also supports the idea that the hard
scattering inside the nuclear medium is closer to perturbative QCD predictions
than is the scattering of isolated protons in free space. We discuss the
application of our approach to electroproduction experiments.


title:
Evidence for Observation of Color Transparency in pa Collisions Using
  Global Fit and Scaling Law Analysis

abstract:
  We review a new systematic data analysis procedure for color transparency
experiments and its application to the proton nucleus scattering experiment.
The method extracts the hard scattering rate as well as the survival
probability for the protons travelling through the nucleus directly from the
data. The method requires modelling of the nuclear attenuation in terms of an
effective nucleon-nucleon cross section. We can minimize this model dependence
by introducing a new scaling law analysis procedure which can yield
considerable information with very little theoretical input. With sufficient
data the functional forms of the survival probability as well as the hard
scattering can be extracted without any theoretical modelling. An analysis of
the BNL data of Carroll {\it et al} shows clear evidence for observation of
color transparency.


title: Soft Photons in $W^+W^-$ Production at LEP200

abstract:
  The pattern of soft photon radiation in $\ee\to\ww$ has a rich structure,
with contributions from photon emission off the initial state and off the final
state particles both before and after decay. In particular, the interference
between the contributions involving the decaying $W$'s depends on the decay
width. We review the theoretical result for the radiation pattern, and present
predictions for LEP200, {\it i.e.} in $\ee$ annihilation just above $\ww$
threshold.


title: Constraints on a Massive Dirac Neutrino Model

abstract:
  We examine constraints on a simple neutrino model in which there are three
massless and three massive Dirac neutrinos and in which the left handed
neutrinos are linear combinations of doublet and singlet neutrinos. We examine
constraints from direct decays into heavy neutrinos, indirect effects on
electroweak parameters, and flavor changing processes. We combine these
constraints to examine the allowed mass range for the heavy neutrinos of each
of the three generations.


title: Heat-Kernel Calculation of Quark Determinant and Computer Algebra

abstract:
  In this paper there we describe the calculational background of deriving a
strong meson Lagrangian from the Nambu--Jona-Lasinio quark model using the
computer algebra systems FORM and REDUCE in recursive algorithms, based on the
heat-kernel method for the calculation of the quark determinant.


title: Radiative Kaon Decays and $CP$ Violation

abstract:
  The amplitudes of $K \rightarrow \pi \gamma^* \rightarrow \pi e^+e^-$ and $K
\rightarrow \pi \pi \gamma$ decays have been calculated within chiral
Lagrangian approach including higher-order derivative terms and meson loops.
The selfconsistency of the simultaneous description of the experimental data on
the nonleptonic and radiative kaon decays have been demonstrated. We estimate
the effects of ``indirect'' and ``direct'' $CP$-violation in $K^0_L \rightarrow
\pi^0 e^+e^-$ decays and discuss $CP$-violating charge asymmetries in $K^{\pm}
\rightarrow \pi^{\pm} \pi^0 \gamma$ decays.


title: Experimental determination of Chiral Symmetry Breaking Parameters

abstract:
  In the low energy domain, Chiral Perturbation Theory parametrizes the small
chiral symmetry breaking effects, produced by the quark masses $m_u$, $m_d$ and
$m_s$, in terms of order parameters of massless QCD. The latter can then, in
principle, be measured in high precision, low energy experiments. We discuss
several relevant processes and possible improvements at future high luminosity
tau/charm or K factories. (talk given at the XXVIIIth Rencontres de Moriond on
QCD and High Energy Hadronic Interactions, Les Arcs (France), March 20-27
1993.)


title:
A possible experimental determination of $m_s/{\hat m}$ from $K_{\mu 4}$
  decays

abstract:
  $K\pi$ scattering and $K_{\mu 4}$ decays are studied at leading order of
improved chiral perturbation theory. It is shown that high precision $K_{\mu
4}$ experiments at, e.g., DA$\Phi$NE should allow for a direct measurement of
the quark mass ratio $m_s$/${\hat m}$.


title:
On the Origin of the Enhancementof CP-violating Charge Asymmetries in $K
  \rightarrow 3\pi$ Decays Predicted from Chiral Theory

abstract:
  We present an analysis of the enhancement of CP-violating charge asymmetries
in $K \rightarrow 3\pi$ decays. Calculations of decay amplitudes are performed
on the basis of bosonized strong and weak Lagrangians derived from
QCD-motivated quark Lagrangians. We show that the interplay of fourth-order
contributions of chiral Lagrangians for strong interactions and penguin
operators in weak interactions significantly enhances the charge asymmetries.


title: Electromagnetic properties of the neutrinos and the pion radiative decay

abstract:
  We investigate the implications of neutrino electromagnetic dipole moments
for the radiative decay $\pi \rightarrow e \nu \gamma$. We show that the
dominant new effect comes from the interference between the amplitude of the
process with the photon emitted by the neutrino and the structure dependent
standard amplitude. Such interference takes place only if the massive neutrino
is a Majorana fermion. Moreover, since electric and magnetic dipole moments
give rise to contributions with opposite signs, future experiments might be
able to distinguish between them.


title: Two-Photon Decay Widths of Higgs Particles

abstract:
  Two--photon decays of Higgs bosons are important channels for the search of
these particles in the intermediate mass range at the $pp$ colliders LHC and
SSC. Dynamical aspects of the Higgs coupling to two photons can also be studied
by means of the $\gamma \gamma$ fusion of Higgs particles at high--energy
e$^+$e$^-$ linear colliders. Extending earlier analyses which had been
restricted to the Standard Model, we present in this note the QCD radiative
corrections to the $\gamma \gamma$ decay widths of scalar and pseudoscalar
Higgs particles in multi--doublet extensions of the Higgs sector, as realized
for instance in supersymmetric theories.


title: Bound States in the Continuum from Supersymmetric Quantum Mechanics

abstract:
  Starting from a potential with a continuum of energy eigenstates, we show how
the methods of supersymmetric quantum mechanics can be used to generate
families of potentials with bound states in the continuum [BICs]. We also find
the corresponding wave functions. Our method preserves the spectrum of the
original potential except it adds these discrete BICs at selected energies.
Specifically, we compute and graph potentials which have bound states in the
continuum starting from a null potential representing a free particle and from
both the attractive and the repulsive Coulomb potentials.


title: Metacolor

abstract:
  A new mechanism is presented for the generation of quark and lepton masses,
based on a heavy fourth family and a new sector of massless fermions. The
massless fermions have only discrete chiral symmetries and they are confined by
the metacolor force. The resulting electroweak corrections may be smaller than
in technicolor theories.


title: Neutrinoless Double Beta Decay and CP Violation

abstract:
  We study the relation between the Majorana neutrino mass matrices and the
neutrinoless double beta decay when CP is not conserved. We give an explicit
form of the decay rate in terms of a rephasing invariant quantity and
demonstrate that in the presence of CP violation it is impossible to have
vanishing neutrinoless double beta decay in the case of two neutrino
generations (or when the third generation leptons do not mix with other leptons
and hence decouple).


title: Closing in on Supersymmetry

abstract:
  A survey is made of some recent ideas and progress in the phenomenological
applications of Supersymmetry (SUSY). We describe the success of SUSY-GUT
models, the expected experimental signatures and present limits on SUSY partner
particles, and the phenomenology of Higgs bosons in the minimal SUSY model.}


title:
Heavy Quark and Chiral Symmetry Predictions for Semileptonic Decays
  B->D(D*),pi,l,nu

abstract:
  We study in detail the prediction for the semileptonic decays $\bar{B} \to D
(D^*) \pi \ell \bar{\nu}$ by heavy quark and chiral symmetry. The branching
ratio for $\bar{B} \to D \pi \ell \bar{\nu}$ is quite significant, as big as
$(0.5-1)\%$. The branching ratio for $\bar{B} \to D^* \pi \ell \bar{\nu}$ is
only of order $10^{-4}-10^{-5}$. Numerical results for various single particle
spectra and their dependence on the pion momentum cutoff schemes are presented
in a series of figures, as are the model independent ratios for differential
rates of $D$ and $D^*$. We also study the parity-violation effects on the decay
rates for different polarization states of the $D^*$. Figures may be obtained
by anonymous FTP from strange.tn.cornell.edu in the directory pub/CLNS931204,
or by email from the author.


title: A Note on `Hot Spot' Hunting in Deep-Inelastic Scattering

abstract:
  We consider the inclusive cross section for jet production with large
transverse momentum in deep-inelastic scattering. This process has been
proposed as a probe of small-x physics, particularly the measurement of `hot
spots' inside the proton. We present a numerical calculation of this process,
taking into account a larger phase space. The theoretical reliability as well
as phenomenological uncertainties of the calculation are discussed.


title: Simulating Supersymmetry with ISAJET 7.0/ ISASUSY 1.0

abstract:
  We review the physics assumptions and input used in ISAJET~7.0 /
ISA\-SUSY~1.0 that are relevant for simulating fundamental processes within the
framework of the Minimal Supersymmetric Standard Model (MSSM) at $p\bar p$ and
$pp$ colliders. After a brief discussion of the underlying MSSM framework, we
discuss event simulation and list the sparticle production processes and decay
modes that have been incorporated into our calculations. We then describe how
to set up and run an ISAJET / ISASUSY job and the user input and output
formats. The ISAJET program is sufficiently flexible that some non-minimal
supersymmetry scenarios may be simulated as well. Finally, plans for future
upgrades which include the extension to $e^+ e^-$ collisions, are listed.


title: The Rate for $B\bbar$ Production Accompanied by a Single Pion

abstract:
  We study the rate for the production of ${B B^\pm \pi^\mp}$, where the sign
of the charged pion tags the flavor content of the neutral $B$ meson. We
estimate this branching ratio, employing the heavy meson chiral effective
theory. We find that at center of mass energy of approximately 12 GeV, a $B$
meson pair should be produced as often with and without an accompanying charged
pion. We also calculate two pion production at this center of mass energy, and
find that it is negligible, as is the rate for rho production. We consider the
implications for CP violation studies. (Invited Talk, 1993 Electroweak
Rencontres de Moriond)


title:
An Effective $p_T$ Cutoff for the Isolalated Lepton Background from
  Bottom Decay --

abstract:
  There is a strong correlation between the $p_T$ and isolation of the lepton
coming from $B$ decay. Consequently the isolated lepton background from $B$
decay goes down rapidly with increasing lepton $p_T$; and there is a $p_T$
cutoff beyond which it effectively vanishes. For the isolation cut of $E^{AC}_T
< 10$ GeV, appropriate for LHC, the lepton $p_T$ cutoff is 80 GeV. This can be
exploited to effectively eliminate the $B$ background from the like sign
dilepton channel apropriate for Majorana particle searches, as well as the
unlike sign dilepton and the single lepton channels appropriate for the top
quark search. We illustrate this with a detailed analysis of the $B$ background
in these channels along with the signals at LHC energy using both parton level
MC and ISAJET programs.


title: A Lattice Monte Carlo Study of the Hot Electroweak Phase Transition

abstract:
  We study the finite temperature electroweak phase transition with lattice
perturbation theory and Monte Carlo techniques. Dimensional reduction is used
to approximate the full four-dimensional SU(2) + a fundamental doublet Higgs
theory by an effective three-dimensional SU(2) + adjoint Higgs + fundamental
Higgs theory with coefficients depending on temperature via screening masses
and mass counterterms. Fermions contribute to the effective theory only via the
$N_F$ and $m_{\rm top}$ dependence of the coefficients. For sufficiently small
lattices ($N^3 < 30^3$ for $m_H$ = 35 GeV) the study of the one-loop lattice
effective potential shows the existence of the {\em second} order phase
transition even for the small Higgs masses. At the same time, a clear signal of
a {\em first order} phase transition is seen on the lattice simulations with a
transition temperature close to but less than the value determined from the
perturbative calculations. This indicates that the dynamics of the first order
electroweak phase transition depends strongly on non-perturbative effects and
is not exclusively related to the so-called $\phi^3$ term in the effective
potential.


title: Minijet corrections to Higgs production

abstract:
  We study higher order corrections to Higgs production with an associated jet
at SSC energies, using the resummation of the leading logarithmic contributions
to multiple gluon emissions due to Lipatov and collaborators. We find a
considerable enhancement of Higgs production at large transverse momenta.


title:
Heavy Fermion Production and the Symmetry Breaking Sector of the
  Electroweak Interactions

abstract:
  We point out that heavy fermion production through the fusion of the
longitudinal gauge bosons might be relevant in probing the strongly interacting
symmetry breaking sector of the electroweak interactions, by showing the
dependence of the one loop amplititude for ($ w^{+} w^{-} \rightarrow
\overline{t} t $) on the symmetry breaking mechanism. The one loop amplitude
for ($ w^{+} w^{-} \rightarrow \overline{t} t $) is calculated for the standard
model and extended technicolour theory. Techni-rho meson exchange is also
briefly discussed.
  We find at $m_{t} = 150 ~GeV$ the cross section of top pair production in $
e^{+} e^{-}$ collisions is comparable in order of magnitude to that of the
longitudinal gauge boson scattering.


title: QCD Calculation of the $B \rightarrow \pi,K$ Form Factors

abstract:
  We calculate the form factors for the heavy-to-light transitions
$B\rightarrow \pi,K $ by means of QCD sum rules using $\pi$ and $K$ light-cone
wave functions. Higher twist contributions as well as gluonic corrections are
taken into account. The sensitivity to the shape of the leading-twist wave
functions and effects of SU(3)-breaking are discussed. The results are compared
with quark model predictions and with the results from QCD sum rules for
three-point correlators.


title:
A Bjorken sum rule for semileptonic $\Omega_b$ decays to ground and
  excited charmed baryon states

abstract:
  We derive a Bjorken sum rule for semileptonic $\Omega_b$ decays to ground and
low-lying negative-parity excited charmed baryon states, in the heavy quark
limit. We discuss the restriction from this sum rule on form factors and
compare it with some models.


title: Heavy Quark Fragmentation into Heavy Mesons

abstract:
  We present a QCD based interpretation of heavy quark fragmentation which
utilizes the heavy quark mass expansion. By distinguishing between perturbative
and non-perturbative QCD effects, we show how to reliably extract mass
independent parameters characterizing the fragmentation function. Because these
parameters are quark mass independent, this procedure should permit tests of
heavy quark symmetry. Furthermore, we show that heavy quark mass corrections
vanish at order $m^2/Q^2$ in QCD. There also exist higher twist corrections of
order $\Lambda m/Q^2$ and ${\alpha_{QCD}\over\pi} {m^2\over Q^2} \ln (Q^2/m^2)$
which we relate to the leading twist fragmentation function.


title: Multi Particle Semiclassical Process in \PHI^4 Theory

abstract:
  We have shown an example of semiclassical transition in \phi^4 model with
positive coupling constant. This process describes a semiclassical transition
between two coherent states with much smaller average number of particles in
the initial state than in the final state. This transition is technically
analogous to the one-instanton transition in the electroweak model. It is
suppressed by the factor exp(-2S), where S is Lipatov instanton action. It
could be important to the problem of calculation of amplitudes for
multiparticle production in \phi^4-type models.


title: Heavy Top Quark Searches in the Di-Lepton Mode at the Tevatron

abstract:
  We present the results of a detailed study of the effects of $b$-tagging on
the heavy top-quark signal and backgrounds for the modes of the di-lepton plus
two high transverse energy jets at the Fermilab Tevatron. The general
characteristics of the heavy top-quark signal events are also discussed so that
a comparison can be made between $b$-tagging and imposing stringent kinematical
cuts to eliminate backgrounds.


title: Discovering Supersymmetry with Like-sign Dileptons

abstract:
  Supersymmetry may be discovered at hadron colliders by searching for events
similar to the top quark signal of two isolated leptons. In the case of gluino
production, the most distinguishing feature is that in half the events the two
leading leptons have the same sign. We demonstrate the remarkable sensitivity
of this gluino signature at both the Fermilab Tevatron Collider and at the
Superconducting Super Collider. Techniques for approximately determining the
gluino mass are discussed.


title:
The Bottom Mass Prediction in Supersymmetric Grand Unification;
  Uncertainties and Constraints

abstract:
  Grand unified theories often predict unification of Yukawa couplings (e.g.,
$h_{b} = h_{\tau}$), and thus certain relations among fermion masses. The
latter can distinguish these from models that predict only coupling constant
unification. The implications of Yukawa couplings of the heavy-family in the
supersymmetric extension of the standard model (when embedded in a GUT) are
discussed. In particular, uncertainties associated with $m_{t}$ and $m_{b}$,
threshold corrections at the low-scale, and threshold and
nonrenormalizable-operator corrections associated with a grand-unified sector
at the high-scale are parametrized and estimated. The implication of these and
of the correlation between $m_{t}$ and the prediction for $\alpha_{s}$ are
discussed. Constraints on the $\tan\beta$ range in such models and an upper
bound on the $t$-quark pole mass are given and are shown to be affected by the
$\alpha_{s}-m_{t}$ correlation. Constraints on the low-scale thresholds are
found to be weakened by uncertainties associated with the high-scale.


title: Contribution of Scalar Loops to the Three-Photon Decay of the Z

abstract:
  I corrected 3 mistakes from the first version: that were an omitted Feynman
integration in the function f^3_{ij}, a factor of 2 in front of log f^3_{ij} in
eq.2 and an overall factor of 2 in Fig.1 c). The final result is changed
drastically. Doing an expansion in the Higgs mass I show that the matrix
element is identically 0 in the order (MZ/MH)^2, which is due to gauge
invariance. Left with an amplitude of the order (MZ/MH)^4 the final result is
that the scalar contribution to this decay rate is several orders of magnitude
smaller than those of the W boson and fermions.


title: Introductory Low-Energy Supersymmetry

abstract:
  Low-energy supersymmetry is a theoretical extension of the Standard Model of
particle physics in which supersymmetry is invoked to explain the origin of the
electroweak scale. In this approach, the energy scale of supersymmetry breaking
can be no larger than about 1 TeV. In these lectures, a pedagogical account of
softly broken supersymmetric gauge theories is presented. The minimal
supersymmetric extension of the Standard Model (MSSM) is defined and
constraints on its parameters are explored. The implications of supersymmetric
tree-level interactions and its one-loop corrections are discussed. Low-energy
supersymmetric model alternatives to the MSSM are briefly mentioned.


title: Existence of a New Instanton in Constrained Yang-Mills-Higgs Theory

abstract:
  Our goal is to discover possible new 4-dimensional euclidean solutions
(instantons) in fundamental SU(2) Yang-Mills-Higgs theory, with a constraint
added to prevent collapse of the scale. We show that, most likely, there exists
one particular new constrained instanton (\Istar) with vanishing Pontryagin
index. This is based on a topological argument that involves the construction
of a non-contractible loop of 4-dimensional configurations with a certain
upperbound on the action, which we establish numerically. We expect \Istar to
be the lowest action non-trivial solution in the vacuum sector of the theory.
There also exists a related static, but unstable, solution, the new sphaleron
\Sstar. Possible applications of \Istar to the electroweak interactions include
the asymptotics of perturbation theory and the high-energy behaviour of the
total cross-section.


title: Mass Limits of Invisibly Decaying Higgs Particles from the LEP Data

abstract:
  In the Majoron models the $SU(2)$ doublet Higgs can decay invisibly into a
Majoron pair via its mixing with a singlet. An analysis of the LEP data shows
the invisible decay mode to be more visible than the SM decay. For these
models, the dominantly doublet Higgs $H$ is shown to have a mass limit within
$\pm 6$ GeV of the SM limit irrespective of the model parameters. But the
dominantly singlet one $S$ can be arbitrarily light for sufficiently small
mixing angle.


title: Retarded-Advanced N-point Green Functions in thermal field theories

abstract:
  The general relationship between a Retarded-Advanced Green function of the
Real Time formalism and analytical continuations of the Imaginary Time
Amplitude is obtained via perturbation theory. A 4-point R-A function is, at
most, a linear combination of three analytical continuations, and a 5-point R-A
function of seven continuations. The R-A functions are written as the sum of
one analytical continuation plus discontinuities across single momentum
transfer variables. These discontinuities


title:
Screening Mass from Chiral Perturbation Theory, Virial Expansion, and
  the Lattice

abstract:
  We calculate the electric screening mass in hot hadronic matter using two
different approaches, chiral perturbation theory and the relativistic virial
expansion with empirical phase shifts, and compare the results to each other
and to a gas of free pions and $\rho$ mesons. We also compute the electric
screening mass for noninteracting, charged bosons with mass $m$ on a lattice to
study likely finite size effects in lattice gauge theory simulations of
continuum QCD. For a lattice of given size, the continuum can be properly
represented only for a window in the ratio $T/m$.


title: Astrophysical Solutions are Incompatible with the Solar Neutrino Data

abstract:
  We consider the most general solar model, using the neutrino fluxes as free
parameters constrained only by the solar luminosity, and show that the combined
solar neutrino data exclude any astrophysical solution at 98\% C.L.\ Our best
fit to the $^7$Be and $^8$B fluxes is respectively $<$7\% and 37$\pm$4\% of the
standard solar model prediction, but only with a large $\chi^2$ (5.6 for 1
d.f.). This best fit to the fluxes contradicts explicit nonstandard solar
models, which generally reduce the $^8$B flux more than the $^7$Be. Those
models are well parameterized by a single parameter, the central temperature.


title:
Coupling Constant and Yukawa Coupling Unifications: Uncertainties and
  Constraints

abstract:
  The status of coupling constant unification (with and without a unification
of Yukawa couplings) is discussed. Uncertainties associated with the input
coupling constants, $m_{b}$ and $m_{t}$, threshold corrections at the low and
high scale, and possible nonrenormalizable operators are described and a
discrepancy between effective and physical scales is pointed out. Theoretical
uncertainties in the predictions of $\alpha_{s}(M_{Z})$, $m_{b}$, and the
unification scale, $M_{G}$, are discussed and estimated. Constraints on the
super-partner spectrum are found to be weak if uncertainties associated with
the high-scale are included. However, requiring $h_{b} = h_{\tau}$ at $M_{G}$
excludes $3 < \tan \beta < 40$ (for $m_{t} < 200$ GeV).


title:
Analyticity Properties and Unitarity Constraints of Heavy Meson Form
  Factors

abstract:
  We derive new bounds on the b-number form factor $F(q^2)$ of the B meson.
(Revised version of hep-ph/9306214).


title:
Studying minijets via the $p_T$ dependence of two-particle correlation
  in azimuthal angle $\phi$

abstract:
  Following my previous proposal that two-particle correlation functions can be
used to resolve the minijet contribution to particle production in minimum
biased events of high energy hadronic interactions, I study the $p_T$ and
energy dependence of the correlation. Using HIJING Monte Carlo model, it is
found that the correlation $c(\phi_1,\phi_2)$ in azimuthal angle $\phi$ between
two particles with $p_T>p_T^{cut}$ resembles much like two back-to-back jets as
$p_T^{cut}$ increases at high colliding energies due to minijet production. It
is shown that $c(0,0)-c(0,\pi)$, which is related to the relative fraction of
particles from minijets, increases with energy. The background of the
correlation for fixed $p_T^{cut}$ also grows with energy due to the increase of
multiple minijet production. Application of this analysis to the study of jet
quenching in ultrarelativistic heavy ion collisions is also discussed.


title: Hadronic axion window and the big-bang nucleosynthesis

abstract:
  Hadronic axions with the decay constant $f_a\simeq 10^{6}$ GeV may fulfill
all astrophysical and laboratory constraints discussed so far. In this paper,
we reexamine the possibility of the hadronic axion window while taking into
account the uncertainties of some parameters describing low energy axion
dynamics. It is found that $f_a$ in the range from $3\times 10^5$ GeV to
$3\times 10^6$ can not be excluded by existing arguments. We then examine the
implication of this hadronic axion window for the big-bang nucleosynthesis (NS)
by evaluating the energy density of thermal axions at the nucleosynthesis
epoch. Our analysis yields $(\rho_a/\rho_{\nu})_{NS}=0.4\sim 0.5$ which exceeds
slightly the current best bound $(\rho_a/\rho_{\nu})_{NS}\leq 0.3$.


title: Coherence effects in the current fragmentation region at HERA

abstract:
  The structure of the hadronic final state in deep inelastic scattering at
HERA is studied on the level of the Monte Carlo event generator. Special
emphasis is given to the colour coherence phenomenon in the current
fragmentation region. It is shown that results of perturbative QCD recently
tested in $e^+e^-$ annihilation at LEP also describe production of hadrons in
current fragmentation region of deep inelastic scattering.


title: Astrophysical Limit on the Deformation of the Poincare Group

abstract:
  The deformed Poincar\'{e} group contains a characteristic mass, $\kappa$. At
energies exceeding $\kappa$, deviations from the special theory of relativity
become significant. However, small deviations from ordinary relativistic
kinematics are observable even at energies substantially lower than $\kappa$.
The observation of distant events producing ultra high energy (UHE) particles
leads to a lower limit on $\kappa$. From an analysis of the UHE data on the
burst in the binary system HER X1 in 1986, we deduce $\kappa > 1.3
10^{12}$~GeV.


title: The heavy fermion damping rate puzzle

abstract:
  : We examine again the problem of the damping rate of a moving heavy fermion
in a hot plasma within the resummed perturbative theory of Pisarski and
Braaten. The ansatz for its evaluation which relates it to the imaginary part
of the fermion propagator pole in the framework of a self-consistent approach
is critically analyzed. As already pointed out by various authors, the only way
to define the rate is through additional implementation of magnetic screening.
We show in detail how the ansatz works in this case and where we disagree with
other authors. We conclude that the self-consistent approach is not
satisfactory.


title: Baryonic Correlation Functions in the Random Instanton Vacuum

abstract:
  We study baryon and diquark correlation functions in the framework of an
instanton model for the QCD vacuum. The model naturally accomodates a light
scalar diquark. As a consequence, the correlation functions for the nucleon and
delta are found to be qualitatively different. Using a complete set of all
available correlation functions we determine masses and coupling constants for
these particles. We compare our results with predictions from QCD sum rules and
recent lattice measurement of point-to-point correlators.


title:
Constraints on Cosmic Strings due to Black Holes Formed from Collapsed
  Cosmic String Loops

abstract:
  The cosmological features of primordial black holes formed from collapsed
cosmic string loops are studied. Observational restrictions on a population of
primordial black holes are used to restrict $f$, the fraction of cosmic string
loops which collapse to form black holes, and $\mu$, the cosmic string
mass-per-unit-length. Using a realistic model of cosmic strings, we find the
strongest restriction on the parameters $f$ and $\mu$ is due to the energy
density in $100 MeV$ photons radiated by the black holes. We also find that
inert black hole remnants cannot serve as the dark matter. If earlier, crude
estimates of $f$ are reliable, our results severely restrict $\mu$, and
therefore limit the viability of the cosmic string large-scale structure
scenario.


title: Long Range Forces from the Cosmological Neutrino Background

abstract:
  The cosmological neutrino background will mediate long range forces between
objects. For a background of temperature T, the potential decreases as 1/r^5
for r >> 1/T and as 1/r for r << 1/T. These forces have large spin-dependent
components. If the neutrino background is nonrelativistic, the long range
forces are enhanced by a factor of the inverse neutrino velocity. These long
range forces may provide a method for observing the cosmological neutrino
background.


title:
New Supersymmetric Two-Higgs-Doublet Structure at the Electroweak Energy
  Scale

abstract:
  Contrary to common belief, the requirement that supersymmetry exists and that
there are two Higgs doublets and no singlet at the electroweak energy scale
does not necessarily result in the minimal supersymmetric standard model
(MSSM). An interesting alternative is presented.


title:
$\pi^+$ and $\pi^0$ Polarizabilities from
  {$\gamma\gamma\rightarrow\pi\pi$} Data on the Base of S-Matrix Approach

abstract:
  We suggest the most model-independent and simple description of the
$\gamma\gamma\rightarrow\pi\pi$ process near threshold in framework of S-matrix
approach. The amplitudes contain the pion polarizabilities and rather
restricted information about $\pi \pi$ interaction. Application of these
formulae for description of MARK-II \cite{M2} and Crystal Ball \cite{CB} data
gives: $(\alpha-\beta)^{C}=(6.0\pm 1.2)\cdot 10^{-42} {\rm cm}^{3}$,
$(\alpha-\beta)^{N}=(-1.4\pm 2.1)\cdot 10^{-42} cm^3$ (in units system $e^2 = 4
\pi \alpha$) at the experimental values of $\pi \pi$ scattering lengths. Both
values are compartible with current algebra predictions.


title:
(Para)bosons, (para)fermions, quons and other beasts in the menagerie of
  particle statistics

abstract:
  After some general comments about statistics and the TCP theorem, I discuss
experimental searches for violations of the exclusion principle and theories
which allow for such violations.


title: Towards a unified string supergravity model

abstract:
  We present a unified string supergravity model based on a string-derived
$SU(5)\times U(1)$ model and a string-inspired supersymmetry breaking scenario
triggered by the $F$-term of the universally present dilaton field. This model
can be described by three parameters: $m_t$, $\tan\beta$, and $m_{\tilde g}$.
We work out the predictions for all sparticle and Higgs masses and discuss the
prospects for their detection at the Tevatron, LEPI,II, and HERA. We find that
the cosmological neutralino relic density is always within current expectations
(\ie, $\Omega_\chi h^2_0\lsim0.9$). We also consider a more constrained version
of this supersymmetry breaking scenario where the $B$-term is specified. In
this case $\tan\beta$ can be determined ($\tan\beta\approx1.4-1.6$) and implies
$m_t\lsim155\GeV$ and $m_h\lsim91\GeV$. Thus, continuing Tevatron top-quark
searches and LEPI,II Higgs searches could probe this restricted scenario
completely.


title: Decay Rate of a Positronium. Review of Theory and Experiment

abstract:
  The present status of theoretical and experimental investigations of the
decay rate of a positronium is considered. The increasing interest to this
problem has been caused by the disagreement of the calculated value of
$\Gamma_3 (o-Ps)$ and the recent series of precise experiments. The necessity
of new calculations on the basis of the quantum field methods in bound state
theory is pointed out with taking into account the dependence of the
interaction kernel on relative energies.


title: Schoonschip '91

abstract:
  The symbolic manipulation program Schoonschip is being made freely available
for a number of computers with Motorola 680x0 cpu's. It can run on machines
with relatively modest memory and disk resources, and is designed to run as
fast as possible given the host constraints. Memory and disk utilization can be
adapted to tune performance. Recently added capabilities include a system for
efficient generation of diagrams, gamma algebra for continuous dimensions,
algorithmic improvements for handling large problems, and an increase in the
allowed number of {\tt X} expressions.


title: Searching for Leptoquarks in electron-photon Collisions

abstract:
  We study the production of composite scalar leptoquarks in $e\gamma$
colliders, and we show that an $e^+e^-$ machine operating in its $e\gamma$ mode
is the best way to look for these particles in $e^+e^-$ collisions, due to the
hadronic content of the photon.


title:
The triple-pomeron regime and the structure function of the pomeron in
  the diffractive deep inelastic scattering at very small x

abstract:
  Misprints and numerical coefficients corrected, a bit of phenomenology and
one figure added. The case for the linear evolution of the unitarized structure
functions made stronger.


title: Octet Baryons at Finite Temperature: QCD Sum Rules vs. Chiral Symmetry

abstract:
  Correlators of the octet baryons in the hot pion gas are studied in the
framework of the QCD sum rule. The condensates appearing in the OPE side of the
correlators become T-dependent through the interaction with thermal pions. We
present an explicit demonstration that the $O(T^2)$-dependence of the
condensates is completely compensated by the change of the pole residue and the
$\pi + B \rightarrow B'$ scattering effect in the spectral functions. Therefore
the baryon masses are constant to this order, although
$\langle\bar{u}u\rangle_T\simeq\langle\bar{u}u\rangle_0(1-T^2/8f_\pi^2)$, which
is consistent with the chiral symmetry constraint by Leutwyler and Smilga.


title: Chiral Symmetry Breaking and Pion Wave Function

abstract:
  We consider here chiral symmetry breaking through nontrivial vacuum structure
with quark antiquark condensates. We then relate the condensate function to the
wave function of pion as a Goldstone mode. This simultaneously yields the pion
also as a quark antiquark bound state as a localised zero mode in vacuum. We
illustrate the above with Nambu Jona-Lasinio model to calculate different
pionic properties in terms of the vacuum structure for breaking of exact or
approximate chiral symmetry, as well as the condensate fluctuations giving rise
to $\sigma$ mesons.


title: A Variational Approach to Bound States in Quantum Field Theory

abstract:
  We consider here in a toy model an approach to bound state problem in a
nonperturbative manner using equal time algebra for the interacting field
operators. Potential is replaced by offshell bosonic quanta inside the bound
state of nonrelativistic particles. The bosonic dressing is determined through
energy minimisation, and mass renormalisation is carried out in a
nonperturbative manner. Since the interaction is through a scalar field, it
does not include spin effects. The model however nicely incorporates an
intuitive picture of hadronic bound states in which the gluon fields dress the
quarks providing the binding between them and also simulate the gluonic content
of hadrons in deep inelastic collisions.


title: Scattering of very light charged particles

abstract:
  I advance arguments against the view that the Lee-Nauenberg-Kinoshita theorem
is relevant in practice to the scattering of charged particles as their mass
tends to zero. I also discuss the case of massive coloured particle scattering.


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

abstract:
  We examine the problem of three generation quark flavor mixing in realistic,
superstring derived standard--like models, constructed in the free fermionic
formulation. We study the sources of family mixing in these models and discuss
the necessary conditions to obtain a realistic Cabibbo--Kobayashi--Maskawa
(CKM) mixing matrix. In a specific model, we estimate the mixing angles and
discuss the weak CP violating phase. We argue that the superstring
standard--like models can produce a realistic CKM mixing matrix. We discuss the
possible textures of quark mass matrices that may be obtained in these models.


title: Low Scale Technicolour at LEP

abstract:
  We discuss the phenomenology of an $SU(2)_{TC}$ technicolour model with a low
technicolour confinement scale ${\Lambda}_{TC} \sim 50-100 GeV$. Such a low
technicolour scale may give rise to the first hints of technicolour being seen
at LEPI and spectacular technicolour signals at LEPII.


title: Chiral Perturbation to One Loop Including the $\rho$ Meson

abstract:
  We formulate the chiral perturbation theory at the one loop level in the
effective lagrangian including the $\rho$ meson as a dynamical gauge boson of a
hidden local symmetry(HLS). The size of radiative correction to the
phenomenological parameter $a$ of HLS is estimated to be about $10$\%. The
complete list of ${\cal O}(E^4)$ terms is given and the one loop counter terms
are determined explicitly in the $N$ flavor model. We also obtain matching
conditions to the conventional chiral perturbation of Gasser and Leutwyler in
the chiral limit in a renormalization scale independent manner. We find that
Gasser--Leutwyler's estimates for $L_{9,10}$ are saturated by $\rho$ and its
one loop contributions without introducing non-minimal couplings of
$\pi$-$\rho$ system, suggesting the absence of the tree level $a_1$ meson
contributions.


title: Real Time Analysis of Thermal Activation via Sphaleron Transitions

abstract:
  We study the process of thermal activation mediated by sphaleron transitions
by analyzing the real-time dynamics of the decay out of equilibrium in a $1+1$
dimensional field theory with a metastable state. The situation considered is
that of a rapid supercooling in which the system is trapped in a metastable
state at a temperature larger than the mass of the quanta, but smaller than the
energy to create a critical droplet. The initial density matrix is evolved in
time and the nucleation rate (probability current at the saddle point) is
computed. The nucleation rate is {\it time dependent}, vanishing at early
times, reaching a maximum at a time $t \approx 1/m$ with $m$ the mass of quanta
in the metastable state, and decreasing at long times as a consequence of
unitarity. An estimate for the average number of particles of ``true vacuum''
produced as a function of time during the nucleation process is obtained.


title: Eigenmoments for Multifragmentation

abstract:
  Linear rate equations are used to describe the cascading decay of an initial
heavy cluster into fragments. Using a procedure inspired by the similar, but
continuous case of jet fragmentation in QCD, this discretized process may be
analyzed into eigenmodes, corresponding to moments of the distribution of
multiplicities. The orders of these moments are usually noninteger numbers. The
resulting analysis can be made time independent and is applicable to various
phenomenological multifragmentation processes, in which case it leads to new
approximate finite-size scaling relations for the spectrum of fragments.


title: Dimensionally Regulated Pentagon Integrals

abstract:
  We present methods for evaluating the Feynman parameter integrals associated
with the pentagon diagram in 4-2 epsilon dimensions, along with explicit
results for the integrals with all masses vanishing or with one non-vanishing
external mass. The scalar pentagon integral can be expressed as a linear
combination of box integrals, up to O(epsilon) corrections, a result which is
the dimensionally-regulated version of a D=4 result of Melrose, and of van
Neerven and Vermaseren. We obtain and solve differential equations for various
dimensionally-regulated box integrals with massless internal lines, which
appear in one-loop n-point calculations in QCD. We give a procedure for
constructing the tensor pentagon integrals needed in gauge theory, again
through O(epsilon^0).


title: The Proton Spin and the Wigner Rotation

abstract:
  It is shown that in both the gluonic and strange sea explanations of the
Ellis-Jaffe sum rule violation discovered by the European Muon Collaboration
(EMC), the spin of the proton, when viewed in in its rest reference frame,
could by fully provided by quarks and antiquarks within a simple quark model
picture, taken into account the relativistic effect from the Wigner rotation.


title:
Natural Suppression of Higgsino-Mediated Proton Decay in Supersymmetric
  SO(10)

abstract:
  In supersymmetric Grand Unified Theories, proton decay mediated by the
color--triplet higgsino is generally problematic and requires some fine--tuning
of parameters. We present a mechanism which naturally suppresses such dimension
5 operators in the context of SUSY $SO(10)$. The mechanism, which implements
natural doublet--triplet splitting using the adjoint higgs, converts these
dimension 5 operators effectively into dimension 6. By explicitly computing the
higgs spectrum and the resulting threshold uncertainties we show that the
successful prediction of $\sin^2\theta_W$ is maintained {\it as a prediction}
in this scheme. It is argued that only a weak suppression of the higgsino
mediated proton decay is achievable within SUSY $SU(5)$ without fine--tuning,
in contrast to a strong suppression in SUSY $SO(10)$.


title: Spontaneous Breaking of Chiral Symmetry as a Consequence of Confinement

abstract:
  We show that at the leading order in the large-$N$ expansion a lattice QCD
motivated linear rising confinement potential at large distances leads to a
non-local four-quark interaction that realizes spontaneous breaking of chiral
symmetry (SBCS) in the same way the Nambu-Jona-Lasinio model does. The
dynamical quark mass $m$, which represents the solution of the gap-equation, is
proportional to the square root of the string tension $\sigma$ and takes the
form at the leading order in the large-$N$ expansion $m=2 \sqrt{\sigma}/\pi$
with $\sigma=0.27$ GeV$^2$. The Nambu-Jona-Lasinio phenomenological constant
$G_1$, which is responsible for SBCS, is expressed in terms of the string
tension and the confinement radius.


title: Light gluinos in high-Q2 deep inelastic scattering

abstract:
  A slight incompatibility in recent low-energy and high-energy \alpha_s
measurements can be interpreted as evidence for new light colour degrees of
freedom. Assuming that these are the gluinos of a supersymmetric extension of
the Standard Model, we investigate to what extent they change the standard QCD
predictions for deep inelastic structure functions, and in particular whether
thay can be detected in such measurements at HERA. We present a modified set of
parton distributions which includes a light gluino distribution and which can
be used for further phenomenological investigations.


title: Mass Scales and Stability of the Proton in [SU(6)]$^{3}\times$Z$_{3}$

abstract:
  We proof that the proton is stable in the left-right symmetric gauge model
[SU(6)]$^3\times$Z$_3$, which unifies nongravitational forces with flavors,
broken spontaneously by a minimal set of Higgs Fields and Vacuum Expectation
Values down to SU(3)$_{c}\otimes$U(1)$_{EM}$\hspace{0.2cm} . We also compute
the evolution of the gauge coupling constants and show how agreement with
precision data can be obtained.


title: Vector Particle Interactions In the Quasipotential Approach

abstract:
  The composite system, formed by two $S=1$ particles, is considered. The field
operators of constituents are transformed on the $(1,0)\oplus (0,1)$
representation of the Lorentz group. The problem of interaction of $S=1$
particle with the electromagnetic field is also discussed.


title:
The Impact of COBE on Inflation, Dark Matter, and Structure Formation: a
  Brief Review

abstract:
  The COBE results, to be followed in the near future by other Cosmic Microwave
Background measurements, are providing us with a new fundamental tool to probe
the formation of large scale structure in the Universe, and in so doing to
constrain our models of the early universe and the nature of dark matter. I
describe briefly here how to interpret the COBE results data with these in
mind, and conclude with a discussion of implications for the future.


title:
New Signals for Gluinos and Squarks of Supergravity at the Tevatron
  Collider

abstract:
  Within the supergravity framework, sleptons are expected to be considerably
lighter than squarks if gluinos and squarks are approximately degenerate. This
can lead to a significant enhancement in leptonic branching ratio for
neutralinos, and sometimes, charginos. Using ISAJET 7.0/ISASUSY 1.0, we
evaluate the multilepton signals from cascade decays of gluinos and squarks
produced at the Fermilab Tevatron $p\bar p$ collider assuming squark and
slepton masses are related as in supergravity models. We find observable cross
sections for spectacular event topologies: $m$-lepton + $n$-jet + $\eslt$
events ($m \leq 4$, $n \geq 2$) and same-sign dilepton + $\eslt$ events and
show that the SM backgrounds to the isolated trilepton, four lepton and
same-sign dilepton signals are very small. These signals can extend the mass
reach of the Tevatron experiments to $m_{\tg}\sim 300$~GeV if $m_{\tg}\sim
m_{\tq}$ and ${\cal O}(1000)$ pb$^{-1}$ of data are collected.


title:
Is the scalar meson seen in CELLO data on
  $\gamma\gamma\rightarrow\pi^+\pi^-$ ?

abstract:
  We analyze the CELLO angular distributions
$\gamma\gamma\rightarrow\pi^+\pi^-$ with the unitary model \cite{KS-86} for
helicity 2 amplitude. In contrast to previous analysis \cite{CELLO} we do not
see any QED damping. The obtained S--wave does not contradict to low--energy
theorem and demonstrates more clealy the resonance--like behaviour near 1.3
Gev.


title:
Factorization of gravitational Compton scattering amplitude in the
  linearized version of general relativity

abstract:
  Gravitational Compton scattering process with a massive fermion is studied in
the context of the linearized gravity. Gravitational gauge invariance and
graviton transversality cause the transition amplitude to be factorized into
that of scalar QED Compton scattering and that of fermion QED Compton
scattering with an overall kinematical factor. The factorization is shown
explicitly and its physical implications are discussed.


title: $\mu$-$e$ conversion in nuclei and Z$^\prime$ physics

abstract:
  Together with the existence of new neutral gauge bosons, models based on
extended gauge groups (rank $> 4$) often predict also new charged fermions. A
mixing of the known fermions with new states with {\it exotic} weak-isospin
assignments (left-handed singlets and right-handed doublets) will induce tree
level flavour changing neutral interactions mediated by $Z$ exchange, while if
the mixing is only with new states with {\it ordinary} weak-isospin
assignments, the flavour changing neutral currents are mainly due to the
exchange of the lightest new neutral gauge boson $Z^\prime$. We show that the
present experimental limits on $\mu-e$ conversion in nuclei give a
nuclear-model-independent bound on the $Z$-$e$-$\mu$ vertex which is twice as
strong as that obtained from $\mu\to e e e$. In the case of E$_6$ models these
limits provide quite stringent constraints on the $Z^\prime$ mass and on the
$Z-Z^\prime$ mixing angle. We point out that the proposed experiments to search
for $\mu-e$ conversion in nuclei have good chances to find evidence of lepton
flavour violation, either in the case that new exotic fermions are present at
the electroweak scale, or if a new neutral gauge boson $Z^\prime$ of E$_6$
origin lighter than a few TeV exists.


title:
A Common Explanation for the Atmospheric, Solar-Neutrino and Double Beta
  Decay Anomalies

abstract:
  We make a number of small changes, including correcting an error in our
heavy-neutrino decay rate. None of our analysis is changed, either in substance
or detail.


title: Rapidity gap signals in Higgs production at the SSC

abstract:
  We examine the structure of the underlying event in neutral Higgs production
at the Superconducting-Supercollider (SSC). Gaps, regions of rapidity
containing no soft particle production, can provide a clean signature for $W$
boson fusion to the heavy Higgs. We first examine the physical basis of gap
production and estimate the survival probability of gaps in the minijet model.
Then, using PYTHIA, and HERWIG we compare gap events to $W$ pair production
from top decay and $q\bar{q}$ fusion. We find that, if experimental problems
can be overcome, gaps should provide a small, but clean, signal for heavy Higgs
production at the SSC.


title: Anomalous $WWZ$ couplings and $K_L\rightarrow \mu^+ \mu^-$

abstract:
  We study contributions to $K_L \rightarrow \mu^+\mu^-$ from anomalous $WWZ$
interactions. There are, in general, seven anomalous couplings. Among the seven
anomalous couplings, only two of them contribute significantly. The others are
suppressed by factors like $m_s^2/M_W^2$, $m_d^2$, or $m_K^2/M_W^2$. Using the
experimental data on $K_L\rightarrow \mu^+\mu^-$, we obtain strong bounds on
the two anomalous couplings.


title:
Supersymmetry Breaking Threshold Corrections in the $SU(4)\times
  SU(2)_L\times SU(2)_R$ Model

abstract:
  We evaluate the SUSY and top threshold effects in the context of the MSSM and
the string derived model based on SU(4)$\times$SU(2)$_L\times$SU(2)$_R$. In
both cases we run the two loop RGEs and determine the lower bounds of the
supersymmetric particle masses, dictated by the experimentally accepted regions
of the values of the low energy parameters.


title: The Strongly Interacting $WW$ System: Gold--Plated Modes

abstract:
  In this paper we survey the signals and backgrounds for a
strongly-interacting electroweak symmetry breaking sector at hadron
supercolliders in the TeV region. We study the process pp->WWX, and compute the
rates for the ``gold-plated'' channels, where W^{+/-}->l^{+/-}\nu and Z ->
l^+l^- (l = e,\mu), for a wide variety of models. Using a forward jet-tag, a
central jet-veto and a back-to-back lepton cut to suppress the Standard Model
backgrounds, we demonstrate that the SSC and LHC have substantial sensitivity
to strong interactions in the electroweak symmetry breaking sector.


title: Higher Dimensional Operators and Low Energy Left-Right Symmetry

abstract:
  We consider higher dimensional operators due to quantum gravity or
spontaneous compactification of extra dimensions in Kaluza-Klein type theory
and their effect in the $SO(10)$ Lagrangian. These operators change the
boundary conditions at the unification scale. As a result one can allow
left-right symmetry to survive till very low energy (as low as $\sim$ TeV) for
a wide range of values for the coupling of these higher dimensional operators
and still make the theory compatible with the latest values of $\sin^2
\theta_W$ and $\alpha_s$ derived from LEP. We consider both non-supersymmetric
and supersymmetric cases with standard higgses. Proton lifetime is very large
in these theories.


title: SUSY at High Energy $e\gamma$ and $\gamma\gamma$ Colliders

abstract:
  We investigate the sparticle production processes $e\gamma\goto \sele\sz1$
and $\gamma\gamma\goto \sfermion\overline{\sfermion}$ at high energy $e\gamma$
and $\gamma\gamma$ colliders in the framework of the minimal supersymmetric
standard model (MSSM). It will be shown that the $e\gamma$ colliders would be
more suitable in searching for the heavy selectrons than $ee$ colliders because
of the low mass threshold of the process $e\gamma\goto \sele\sz1$. We show that
the standard background processes $e\gamma\goto \nu W$ and $eZ$ can be
suppressed in terms of initial beam polarization as well as the kinematical
cuts on the energy and angle of the final electron. Moreover, it will be argued
that the experimental measurements of the cross sections for the processes
$e\gamma\goto \sele\sz1$ and $\gamma\gamma\goto \sfb\sf$ could enable us to
constrain the basic parameters in the MSSM. This is originated from the
simplicity of SUSY parameter dependence of these processes. We also give
comments on the stop production at $e^{+}e^{-}$ colliders with the
longitudinally polarized electron beams.


title:
The pion form factor: Sudakov suppressions and intrinsic transverse
  momentum

abstract:
  It is demonstrated that any attempt to calculate the perturbative QCD
contribution to the pion form factor requires the inclusion of intrinsic
transverse momentum besides Sudakov form factors. For momentum transfers of the
order of a few GeV the intrinsic transverse momentum leads to a substantial
suppression of the perturbative QCD contribution.


title: Coherence and Decoherence in Radiation off Colliding Heavy Ions

abstract:
  We discuss the kinetics of a disoriented chiral condensate, treated as an
open quantum system. We suggest that the problem is analogous to that of a
damped harmonic oscillator. Master equations are used to establish a hierarchy
of relevant time scales. Some phenomenological consequences are briefly
outlined.


title:
The Anatomy of eps'/eps Beyond Leading Logarithms with Improved Hadronic
  Matrix Elements

abstract:
  Results of a recent calculation of the effective $\dS$ Hamiltonian at the
next-to-leading order will be presented\footnote{Work done in collaboration
with A. J. Buras and M. E. Lautenbacher.}. These, together with an improved
treatment of hadronic matrix elements, are used to evaluate the measure for
direct CP-violation, $\epe$, at the next-to-leading order. Taking
$\mt=130\,GeV$, $\Lms=300\,MeV$ and calculating $\langle Q_6 \rangle$ and
$\langle Q_8 \rangle$ in the $1/N$ approach, we find in the NDR scheme $\epe =
(6.7 \pm 2.6)\times 10^{-4}$ in agreement with the experimental findings of
E731. We point out however that the increase of $\langle Q_6 \rangle$ by only a
factor of two gives $\epe = (20.0 \pm 6.5)\times 10^{-4}$ in agreement with the
result of NA31. The dependencies of $\epe$ on $\Lms$, $\mt$, and some
$B$-parameters, parameterizing hadronic matrix elements, are briefly discussed.


title: Limits on the Bess Model at NLC

abstract:
  Invited talk at the ``Workshop on Physics and Experiments at Linear e+e-
Colliders'', Waikoloa, Hawaii, April 26-30, 1993 (presented by D. Dominici)


title: The Search for Large Rapidity Gaps Between Jets by DZERO

abstract:
  We have searched for high Pt (>40 GeV/c) jet events in ppbar collisions at
the Fermilab TEVATRON (S**1/2 = 1800 GeV/c2) which have large pseudo-rapidity
differences between the jets and are consistent with zero particle production
from the underlying event. Preliminary analysis indicates that a significant
fraction of these events with "voids" are present. (3 pages of plain text, 7
Figures available on request from the author)