title:
Linear Wave Equations and Effective Lagrangians for Wigner
  Supermultiplets

abstract:
  The relevance of the contracted SU(4) group as a symmetry group of the pion
nucleon scattering amplitudes in the large $N_c$ limit of QCD raises the
problem on the construction of effective Lagrangians for SU(4) supermultiplets.
In the present study we suggest effective Lagrangians for selfconjugate
representations of SU(4) in exploiting isomorphism between so(6) and ist
universal covering su(4). The model can be viewed as an extension of the linear
$\sigma$ model with SO(6) symmetry in place of SO(4) and generalizes the
concept of the linear wave equations for particles with arbitrary spin. We show
that the vector representation of SU(4) reduces on the SO(4) level to a
complexified quaternion. Its real part gives rise to the standard linear
$\sigma$ model with a hedgehog configuration for the pion field, whereas the
imaginary part describes vector meson degrees of freedom via purely transversal
$\rho$ mesons for which a helical field configuration is predicted. As a
minimal model, baryonic states are suggested to appear as solitons of that
quaternion.


title: A model for the $Q^2$ dependence of polarized structure functions

abstract:
  We present an update of a phenomenological model for the spin dependent
structure functions $g_1(x,Q^2)$ of the proton and neutron. This model is based
on a broken SU(6) wavefunction parametrized by the unpolarized structure
functions. The two free parameters of the model are choosen to fulfill the
Bjorken and Ellis--Jaffe sum rules. The model respects isospin symmetry and has
zero strange sea polarization. Using new values for $F/D$ from hyperon beta
decay the resulting $Q^2$ dependent asymmetries $A_1$ are in perfect agreement
with the existing data. Therefore we do not see any evidence for a ``spin
crisis''. With two choices for $g_2$ the $Q^2$ dependence of $A_1(x,Q^2)$ and
$A_2(x,Q^2)\sqrt{Q^2}/M$ is predicted and shown to be small for both cases.


title: HOT SCALAR ELECTRODYNAMICS AS A TOY MODEL FOR HOT QCD

abstract:
  Hot scalar electrodynamics is adopted as a toy model for a hot gluon plasma
to display some aspects of the compulsory resummation of hard thermal loops
when next-to-leading order quantities at soft momentum scales are to be
calculated. [Talk given by A.K.R. at a one-day meeting dedicated to the memory
of Tanguy ALTHERR, held on November 4, 1994 at CERN, Geneva. To appear in a
Gedenkschrift published by World Scientific.]


title: Precision Tests of the MSSM

abstract:
  The LEP data and the measurement of $M_W$ confirm the electro weak symmetry
breaking by the Higgs mechanism with (2--3)\% accuracy. For the Higgs boson
mass, fits to the present data (without the SLD result) give
$M_h=121^{+207}_{-118}$ GeV and $M_h<800$ GeV at 95\% C.L. We analyze those
fits from the point of view of the impact of different measurements on the
final result for $M_h$. All the relevant observables can be grouped into two
categories: those which correlate $M_h$ with $m_t$ and those which constrain
the range of $m_t$. Using this classification we discuss potential improvements
in the limits on $M_h$, anticipating improvements in the precision of the data.
Also the sensitivity of the limits on $M_h$ to the value of $\alpha_s(M_Z)$ is
discussed in a toy model which reproduces all the results of the SM but the
$Z^0\rightarrow\bar bb$ width is increased by hand so that $R_b=0.22$ and, in
consequence, the fitted value of $\alpha_s(M_Z)\approx0.11$ (qualitatively
similar situation occurs in the Minimal Supersymmetric Standard Model with
light chargino and right--handed top squark).


title: Renormalized Soft-Higgs Theorems

abstract:
  The Higgs couplings to matter fields are proportional to their masses. Thus
Higgs amplitudes can be obtained by differentiating amplitudes without Higgs
with respect to masses. We show how this well-known statement can be extended
to higher order when renormalization effects are taken into account. We
establish the connection with the Callan-Symanzik and renormalization group
equations and consider also pseudoscalar Higgs couplings to fermions.
Furthermore, we address the case where the Higgs couples to a heavy particle
that is integrated out from the low-energy effective Lagrangian. We derive
effective interactions where mass logarithms are resummed by
renormalization-group methods, and give expansions of the results up to
next-to-leading order.


title: THE STRUCTURE OF THE POMERON

abstract:
  Results of experiments probing the structure of the pomeron at hadron
colliders and at HERA are reviewed. By renormalizing the pomeron flux factor in
diffraction dissociation as dictated by unitarity, a picture emerges from the
data in which the pomeron appears to be made of valence quark and gluon
color-singlets in a combination suggested by asymptopia.


title: Higher twist corrections to Bjorken sum rule

abstract:
  Some higher twist corrections to the Bjorken sum rule are estimated in the
framework of a quark-diquark model of the nucleon. The parameters of the model
have been previously fixed by fitting the measured higher twist corrections to
the unpolarized structure function $F_2(x, Q^2)$. The resulting corrections to
the Bjorken sum rule turn out to be negligible.


title: Goldstone Bosons in the Appelquist-Terning ETC Model

abstract:
  It is demonstrated that the extended technicolor model proposed recently by
Appelquist and Terning has pair of potentially light $U(1)$ Goldstone bosons
coupling to ordinary matter with strength $2m_f\over F_{\pi}$, where $m_f$ is
the mass of the fermion and $F_{\pi} \approx 125\,\GeV$. These Goldstone bosons
could get a mass if the spontaneously broken $U(1)$ symmetries are also
explicitly broken, by physics beyond that specified in the model. An attempt to
break these symmetries by embedding the model into a larger gauge group seems
to be inadequate. The problem is because there are too many representations and
there is a mismatch between the number of condensates and the number of gauge
symmetries broken.


title: Technipion contribution to $ b\to s\gamma$

abstract:
  We show that the present limit on the inclusive decay $b\rightarrow s\gamma$
provides strong constraints on Technicolor models. In particular, small values
of $F_\pi$ and the mass of charged octet and singlet technipions are excluded,
assuming the most natural form of the technipion coupling to the ordinary
quarks.


title: Analysis of Charge Asymmetry in Rare Dilepton $B$ Decays

abstract:
  We analyze forward-backward charge asymmetry of the lepton production in rare
decays $B\rightarrow X_s l^+l^-$ and $B\rightarrow K^* l^+l^-$, including
vector-resonance effects. Certain regions of phase space, in which the
asymmetry is sensitive to individual short-distance coefficients, are pointed
out. In particular, we suggest a method to test the coupling of the leptonic
axial vector current to the left-handed quark current experimentally.


title:
Reanalysis of the mass difference $B_d^0-\overline B_d^0$\ within the
  Minimal Supersymmetric Standard Model

abstract:
  We present a detailed and complete calculation of the loop corrections to the
mass difference $\Delta m_{B_d^0}/m_{B_d^0}$. We include charginos and scalar
up quarks as well as gluinos and scalar down quarks on the relevant loop
diagrams. We include the mixings of the charginos and of the scalar partners of
the left and right handed quarks. We find that the gluino contribution to this
quantity is important with respect to the chargino contribution only in a small
part of phase space: mainly when the gluino mass is small ($\sim$ 100 GeV) and
the symmetry-breaking parameter $m_S$ is below 300 GeV. This contribution is
also important for very large values of $\tan\beta$ ($\sim$ 50) irrespective of
the other parameters. Otherwise, the chargino contribution dominates vastly and
can be roughly as large as that of the Standard Model. We also present the
contribution of the charged Higgs to the mass difference $\Delta
m_{B_d^0}/m_{B_d^0}$\ in the case $m_b\tan\beta\ll m_t\cot\beta$. This last
contribution can be larger than the Standard Model contribution for small
values of the Higgs mass and small values of $\tan\beta$.


title:
COMPUTATION OF COEFFICIENT FUNCTIONS FOR AN EXPANSION OF PARAPOSITRONIUM
  DECAY WIDTH USING REDUCE

abstract:
  A kind of asymptotic expansion for calculation of the (para)positronium decay
rate is formulated. The method is completely relativistic and gauge invariant.
The expansion goes over the inverse square of relative momentum $k$ of two
photons in Euclidean region and the actual width is determined at $k^2=-m^2$,
$m$ being the electron mass.


title: QCD Renormalons and Higher Twist Effects

abstract:
  I give a short review of the relation of infrared renormalons in QCD and
higher twist effects, with the emphasis on possible applications. In
particular, I present estimates of renormalon-induced uncertainties in deep
inelastic sum rules and explain how the renormalons can potentially be used to
unravel the structure of nonperturbative effects in complicated situations and
to indicate possible systematic sources of large perturbative corrections.


title:
Non-Abelian Gauge Family Symmetry in Rank 8 and 16 Grand Unified String
  Theories

abstract:
  The one of the main points of the investigations in high energy physics is to
study the next chain: a law of the quark and lepton mass spectra $\rightarrow $
the puzzles of the quark and lepton family mixing $\rightarrow $ a possible new
family dynamics. The new family symmetry dynamics might be connected to the
existence of some exotic gauge or matter fields or something yet. For this it
will better to study the possibilities of the appearence this gauge symmetry in
the framework of the Grand Unified String Theories. In the framework of four
dimensional heterotic superstring with free fermions we investigate the rank
eight Grand Unified String Theories (GUST) which contain the $SU(3)_H$-gauge
family symmetry. We explicitly construct GUST with gauge symmetry $G = SU(5)
\times U(1)\times (SU(3) \times U(1))_H$ and $G = SO(10)\times (SU(3) \times
U(1))_H$ $\subset SO(16)$ or $E(6)\times SU(3)_H$ $\subset E(8)$ in free
complex fermion formulation. As the GUSTs originating from Kac-Moody algebras
(KMA) contain only low-dimensional representations it is usually difficult to
break the gauge symmetry. We solve this problem taking for the observable gauge
symmetry the diagonal subgroup $G^{sym}$ of rank $16$ group $G\times G\subset
SO(16)\times SO(16)$ or $(E(6) \times SU(3)_H)^2 $ $\subset E(8)\times E(8)$.
We discuss the possible fermion matter and Higgs sectors in these models. In
these GUST there has to exist "superweak" light chiral matter($m_H^f < M_W$).
The understanding of quark and lepton mass spectra and family mixing leave a
possibility for the existence of an unusually low mass breaking scale of the
$SU(3)_H$ family gauge symmetry


title: Big Bang Nucleosynthesis in Crisis?

abstract:
  A new evaluation of the constraint on the number of light neutrino species
(N_nu) from big bang nucleosynthesis suggests a discrepancy between the
predicted light element abundances and those inferred from observations, unless
the inferred primordial 4He abundance has been underestimated by 0.014 +/-
0.004 (1 sigma) or less than 10% (95%C.L.) of 3He survives stellar processing.
With the quoted systematic errors in the observed abundances and a conservative
chemical evolution parameterization, the best fit to the combined data is N_nu
= 2.1 +/- 0.3 (1 sigma) and the upper limit is N_nu < 2.6 (95% C.L.). The data
are inconsistent with the Standard Model (N_nu = 3) at the 98.6% C.L.


title:
Gluon Production at High Transverse Momentum in the McLerran-Venugopalan
  Model of Nuclear Structure Functions

abstract:
  We consider the production of high transverse momentum gluons in the
McLerran-Venugopalan model of nuclear structure functions. We explicitly
compute the high momentum component in this model. We compute the nuclear
target size $A$ dependence of the distribution of produced gluons.


title:
Exclusive semileptonic decays of B mesons into light mesons in the
  relativistic quark model

abstract:
  The exclusive semileptonic $B\to \pi(\rho) e\nu$ decays are studied in the
framework of the relativistic quark model based on the quasipotential approach
in quantum field theory. The large recoil momentum of the final $\pi(\rho)$
meson allows for the expansion of the decay form factors at $q^2=0$ in the
inverse powers of $b$-quark mass. This considerably simplifies the analysis of
these decays. The $1/m_b$ expansion is carried out up to the first order. It is
found that the $q^2$-dependence of the axial form factor $A_1$ is different
from the $q^2$-behaviour of other form factors. We find $\Gamma(B\to \pi
e\nu)=(3.1\pm 0.6)\times \vert V_{ub}\vert ^2\times 10^{12}$s${}^{-1}$ and
$\Gamma(B\to \rho e\nu)=(5.7\pm 1.2)\times \vert V_{ub}\vert ^2\times
10^{12}$s${}^{-1}$. The relation between semileptonic and rare radiative
$B$-decays is discussed.


title:
Constraints on New Physics in the Electroweak Bosonic Sector from
  Current Data and Future Experiments

abstract:
  Extensions of the Standard Model which involve a new scale, $\Lambda$, may,
for energies sufficiently small compared to this new scale, be expressed in
terms of operators with energy dimension greater than four. The coefficients of
just four SU(2)$\times$U(1)-gauge-invariant energy-dimension-six operators are
sufficient to parameterize the contributions of new physics in the electroweak
bosonic sector to electroweak precision measurements. In this letter we update
constraints on the coefficients of these four operators due to recent precision
measurements of electroweak observables. We further demonstrate how such
constraints may be improved by experiments at TRISTAN, LEP2 and at a future
linear $e^+e^-$ collider. The relationship of these operators to the oblique
parameters $S$, $T$ and $U$ is examined. Two of the operators contribute to a
non-standard running of the electroweak charge form-factors
$\overline{\alpha}(q^2)$, $\overline{s}^2(q^2)$, $\overline{g}_Z^2(q^2)$ and
$\overline{g}_W^2(q^2)$; in the special case where the coefficients of these
two vanish the operator analysis reduces to an analysis in terms of $S$, $T$
and $U$ with $U = 0$.


title:
Remarks on the Cosmological Constant and the $\lambda\Phi^4$ Phase
  Transition

abstract:
  We reanalyze the problem of the cosmological constant associated with the
phase transition in a self-interacting scalar theory. It is pointed out that
the generally accepted ``triviality'' of $(\lambda\Phi^4)_4$ implies a
first-order phase transition. As a consequence, Spontaneous Symmetry Breaking
can be consistent with zero cosmological constant if one assumes that it
vanishes in the symmetric phase $<\Phi>=0$.


title: On a Method of Identification of Leptoquarks Produced in ep Collisions

abstract:
  We analyse numerically manifestations of the radiative amplitude zero (RAZ)
effect in single leptoquark production associated with hard photon emission. We
present some quantitative conclusions on the possibility to distinguish
leptoquark charges produced in ep collisions taking account of three-body final
state subprocesses and of proton structure functions. Applying this method to
HERA and possible LEP+LHC experiments we show that the RAZ analysis can serve
as a tool to determine the leptoquark electric charge up to large leptoquark
masses.


title: Pion structure function in nuclear medium

abstract:
  We study the pion structure function in nuclear medium using the Nambu and
Jona-Lasinio model, and its implication for the nuclear pion enhancement of the
sea quark distribution in nuclei. By using the operator product expansion,
medium effect of the nuclear matter is incorporated in calculations of the
twist-2 operators. We find density dependence of the pion structure function is
rather weak around the nuclear matter density. We also discuss how the medium
modification of the pion structure affects the sea quark enhancement in the
nucleus.


title:
Resolving the Constrained Minimal and Next-to-Minimal Supersymmetric
  Standard Models

abstract:
  We perform a detailed analysis of the next-to-minimal supersymmetric standard
model (NMSSM), imposing the constraints of two-loop gauge coupling unification,
universal soft supersymmetry breaking and the correct pattern of electroweak
symmetry breaking. We compare our results with those for the minimal
supersymmetric standard model (MSSM) using closely related techniques and, as
far as possible, a common set of input and output variables. In general, in the
constrained NMSSM, there are much stronger correlations between parameters than
in the constrained MSSM, and we map out the allowed parameter space. We also
give a detailed discussion of how to resolve the two models experimentally,
concentrating primarily on the prospects at LEPII.


title: Constraining new interactions with leptonic tau decays

abstract:
  The recent measurements of the Michel parameters in tau decays enable, for
the first time, a thorough analysis of the leptonic sector. In general, in
models beyond the Standard Model, these parameters will be altered through
changes in the W and Z couplings, and/or through interactions mediated by new
gauge bosons. We perform a complete, model independent analysis of the
constraints imposed by the present data on such boson-mediated interactions,
and point out the existence of useful relations among the couplings.


title:
The Constituent Quark Limit and the Skyrmion Limit of the Chiral Quark
  Soliton Model

abstract:
  We calculate $g_A^3$ and $g_A^0$ in the Chiral Quark-Soliton Model (or
equivalently in semibosonized Nambu--Jona-Lasinio model) in the limit of small
and large soliton size. In small soliton limit we recover the results of the
Constituent Quark Model. The agreement between the two models is achieved due
to the recently calculated $1/\Nc$ contributions to $g_A^3$ and to $g_A^0$. In
the case of $g_A^3$ these terms arise from the {\it time-ordering} of the
collective operators. For large solitons simple scaling arguments show that the
$1/\Nc$ contributions vanish with the inverse power of the soliton size.


title: Color-octet quarkonia production

abstract:
  Gluon fragmentation represents the dominant source of high energy prompt
quarkonia at hadron colliders. Fragmentation approximations break down,
however, when a quarkonium's transverse momentum becomes comparable to its
mass. In this paper, we identify a large class of color-octet diagrams that
mediate quarkonia production at all energies and reduce to the dominant set of
gluon fragmentation graphs in the high $p_\perp$ limit. They contribute to
quarkonia differential cross sections at the same order as color-singlet
diagrams and bring theoretical predictions for Upsilon and Psi production at
the Tevatron into agreement with experimental measurements. Using recent CDF
data, we extract numerical values for bottomonia and charmonia color-octet
matrix elements which are consistent with NRQCD scaling rules. We also find
that quarkonia generated via the color-octet mechanism are strongly polarized
at low as well as high energies. Spin alignment measurements can thus test the
color-octet quarkonia production picture.


title: Master Formula Approach to Chiral Symmetry Breaking: Pi-Pi scattering

abstract:
  The master formula approach to chiral symmetry breaking is used to analyze
the phase shifts for $\pi\pi$ scattering in the elastic region. The results are
in excellent agreement with the data for the phase shifts up to the K-K bar
threshold. Our analysis shows that the pi-pi data near threshold in the scalar
channel favors a large quark condensate in the vacuum, i.e. <q bar q> \sim
-(240 MeV)^3.


title: New and improved quark-lepton symmetric models

abstract:
  We show how the use of a see-saw mechanism based on a $3 \times 3$ neutrino
mass matrix texture can considerably simplify Higgs sectors for quark-lepton
symmetric models (and for Standard Model extensions generally). The main theory
we discuss also incorporates a previously considered scenario whereby the
charged lepton of a particular generation is necessarily less massive than the
corresponding charge $+2/3$ quark, provided intergenerational mixing is small.


title: Phenomenology of ``Onium'' Production

abstract:
  The phenomenology of heavy quarkonia production in hadron collisions is
reviewed. The theoretical predictions are compared to data. Commonly used
production models are shown to fail in explaining all the experimental
findings. The shortcomings of these models are analysed and possible
improvements are discussed.


title: U(3)-Family Nonet Higgs Boson and its Phenomenology

abstract:
  In a model where quark and lepton masses and family-mixings are caused not by
a variety of Yukawa couplings $y_{ij}$ ($i,j=1,2,3$: family indices) with one
vacuum expectation value (VEV) $v=\langle\phi_L^0\rangle_0$, but by a variety
of VEV's of a U(3)-family nonet Higgs boson $\phi_L$, $v_{i}^j=\langle\phi_{L
i}^{0j}\rangle_0$, with a single coupling constant, the following problems are
investigated: what constraints on the Higgs potential are imposed in order to
provide realistic quark and lepton mass spectra and mixings and what
constraints on the Higgs boson masses are required in order to suppress
unwelcome flavor-changing neutral current effects. Lower bounds of the physical
Higgs boson masses of $\phi_L$ are deduced from the present experimental data
and new physics from the present scenario is speculated.


title: Indirect Neutrino Oscillations

abstract:
  We show how two different scales for oscillations between $e$ and $\mu$
neutrinos, characterized by different mixing angles and effective mass scales,
can arise in a simple and theoretically attractive framework. One scale
characterizes direct oscillations, which can accommodate the MSW approach to
the solar neutrino problem, whereas the other can be considered as arising
indirectly, through virtual transitions involving the $\tau$ neutrino with a
mass $\sim$ 1 eV. This indirect transition allows the possibility of observable
$\bar \nu_\mu \leftrightarrow \bar \nu_e$ oscillations at accelerator and
reactor energies. We discuss specifically the parameters suggested by a recent
experiment at Los Alamos within this framework.


title:
$SU(2N_{f})\otimes O(3)$ light diquark symmetry and current-induced
  heavy baryon transition form factors

abstract:
  We study the current-induced bottom baryon to charm baryon transitions in the
Heavy Quark Symmetry limit as $m_{q}\rightarrow \infty$. Our discussion
involves $s$-wave to $s$-wave as well as $s$-wave to $p$-wave transitions.
Using a constituent quark model picture for the light diquark system with an
underlying $SU(2N_{f})\otimes O(3)$ symmetry and the heavy quark symmetry we
arrive at a number of new predictions for the reduced form factors that
describe these transitions.


title:
Production of neutral pseudo-Goldstone bosons at LEP II and NLC in
  multiscale walking technicolor models

abstract:
  Walking technicolor (WTC) models predict the existence of heavy neutral
pseudo-Goldstone bosons (PGBs), whose masses are typically expected to be
larger than 100 GeV. In this paper, we investigate the production and decay of
these particles at the high energy e^+ e^- experiments, LEP II and NLC. We find
that, in WTC models, the production of neutral PGBs can be significantly
enhanced, by one or two orders of magnitude, with respect to the predictions of
traditional (QCD-like) TC models. The origin of such an enhancement is the
existence of several low energy TC scales, that are likely to appear in WTC
theories. This could allow the PGBs to be observed even at the energy and
luminosity of the LEP II experiment. At LEP II, the PGBs are expected to be
produced in the e^+ e^- ==> P \gamma channel, and, possibly, in the e^+ e^- ==>
P e^+ e^- channel, with a total rate that can be of the order of several tenths
per year. Due to the typical large values of PGB masses, the relative branching
ratios of PGB decays, in WTC theories, are different from those predicted in
traditional TC models. In particular, a large fraction of these decays can
occur in the P ==> \gamma \gamma channel. In considering the PGB production, at
LEP II, we find that, in most of the final states, the distinctive signatures
of WTC events should allow the Standard Model background to be reduced to a
negligible level. We also find that, at a 500 GeV NLC experiment, the
production of neutral PGBs can occur in several channels, and can be of the
order of 10^3 events per year. Instead, when we consider traditional TC models,
we find that no PGB are typically predicted to be observed, both at LEP II and
the NLC experiment.


title: Energy Distribution of $\phi$ in Pure Penguin Induced $B$ Decays

abstract:
  We study the energy distribution of $\phi$ in pure penguin induced
$B\rightarrow X_s \phi$ taking into account the fermi motion of b inside $B$
meson for $b\rightarrow s\phi$ and also modification due to gluon
bremsstrahlung process $b\rightarrow s\phi g$. We find that the contribution to
$B\rightarrow X_s\phi$ from $b\rightarrow s\phi g$ is less than 3\%. This study
provides a criterion for including most of the $\phi$'s produced in a penguin
process.


title: Semiclassical approach for multiparticle production in scalar theories

abstract:
  We propose a semiclassical approach to calculate multiparticle cross sections
in scalar theories, which have been strongly argued to have the exponential
form $\exp(\lambda^{-1}F(\lambda n,\epsilon))$ in the regime $\lambda\to0$,
$\lambda n$, $\epsilon=$ fixed, where $\lambda$ is the scalar coupling, $n$ is
the number of produced particles, and $\epsilon$ is the kinetic energy per
final particle. The formalism is based on singular solutions to the field
equation, which satisfy certain boundary and extremizing conditions. At low
multiplicities and small kinetic energies per final particle we reproduce in
the framework of this formalism the main perturbative results. We also obtain a
lower bound on the tree--level cross section in the ultra--relativistic regime.


title: NEW PHYSICS AND RECENT HIGH PRECISION ELECTROWEAK MEASUREMENTS

abstract:
  We analyze LEP and SLC data from the 1995 Winter Conferences for signals of
new physics. We compare the data with the Standard Model (SM) as well as a
number of test hypotheses concerning the nature of new physics: (i) nonstandard
Zbb couplings, (ii) nonstandard Zff couplings for the entire third generation,
(iii) nonstandard oblique corrections, (iv) nonstandard lepton couplings, (v)
general nonstandard W and Z couplings to all fermions, as well as combinations
of the above. In most of our analyses, we leave the SM variables $\alpha_s$ and
$m_t$ as free parameters to see how the various types of new physics can affect
their inferred values. We find that the best fit ($\chi^2/d.o.f. = 8.4/10$) is
obtained for the nonstandard Zbb couplings, which also give a `low' value
(0.112) for $\alpha_s$. The SM also gives a good description of the Z data,
having $\chi^2/d.o.f. = 12.4/12$. If $\alpha_s$ is held fixed to the low-energy
value 0.112, then we find that a combination of the nonstandard Zbb couplings
is fit to lie more than four standard deviations away from zero.


title:
Precision Tests of CPT Symmetry and Quantum Mechanics in the Neutral
  Kaon System

abstract:
  We present a systematic phenomenological analysis of the tests of CPT
symmetry that are possible within an {\em open} quantum-mechanical description
of the neutral kaon system that is motivated by arguments based on quantum
gravity and string theory. We develop a perturbative expansion in terms of the
three small CPT-violating parameters admitted in this description, and provide
expressions for a complete set of $K \rightarrow 2\pi, 3\pi$ and $\pi\ell\nu$
decay observables to second order in these small parameters. We also illustrate
the new tests of CPT symmetry and quantum mechanics that are possible in this
formalism using a regenerator. Indications are that experimental data from the
CPLEAR and previous experiments could be used to establish upper bounds on the
CPT-violating parameters that are of order $10^{-19}$ GeV, approaching the
order of magnitude that may be attainable in quantum theories of gravity.


title: Do subcritical bubbles hinder first order phase transition?

abstract:
  We consider the role played by subcritical bubbles during the electroweak
phase transition, estimate their average size, amplitude and formation rate
taking into account the crucial role played by thermalization. We also study
the influence of subcritical bubbles on the formation of critical bubbles in
the thin wall regime and show that, contrary to some recent claims, subcritical
bubbles do not affect the nucleation of critical bubbles in an appreciable way.
  From this fact we conclude that the electroweak baryogenesis scenarios
associated with a first order electroweak phase transition still remain an
attractive possibility.


title:
Baryon Asymmetry: Evidence of CP Violation and Phase Transition in the
  Early Universe ?

abstract:
  A talk was given on the baryon asymmetry of our universe within the
electroweak energy scale which was the theme for the 23rd INS Symposium. It was
intended for non-experts by a non-expert speaker. A model is analized
explicitly in which the lepton number produced from the bubble walls is
converted afterwards to the baryon asymmetry.Phase transition dynamics is
simulated, including the temporal develpment and the fusion effect of the
nucleated bubbles.


title: The Strange Quark Distribution

abstract:
  We discuss the latest CCFR determination of the strange sea density of the
proton. We comment on the differences with a previous, leading--order, result
and point out the relevance of quark mass effects and current non--conservation
effects. By taking them into account it is possible to solve the residual
discrepancy with another determination of the strange quark distribution. Two
important sources of uncertainties are also analyzed.


title: MULTIGLUON AMPLITUDES IN THE HIGH-ENERGY LIMIT

abstract:
  We give a unified description of tree-level multigluon amplitudes in the
high-energy limit. We represent the Parke-Taylor amplitudes and the
Fadin-Kuraev-Lipatov amplitudes in terms of color configurations that are
ordered in rapidity on a two-sided plot. We show that for the helicity
configurations they have in common the Parke-Taylor amplitudes and the
Fadin-Kuraev-Lipatov amplitudes coincide.


title: Colour Deconfinement and Quarkonium Dissociation

abstract:
  We survey how quarkonia can be used to probe colour deconfinement in
relativistic nuclear collisions.


title:
The Dual Description of Long Distance QCD and the Effective Lagrangian
  for Constituent Quarks

abstract:
  We describe long distance QCD by a dual theory in which the fundamental
variables are dual potentials coupled to monopole fields and use this dual
theory to determine the effective Lagrangian for constituent quarks. We find
the color field distribution surrounding a quark anti-quark pair to first order
in their velocities. Using these distributions we eliminate the dual potentials
and obtain an effective interaction Lagrangian $L_I ( \vec x_1 \, , \vec x_2 \,
; \vec v_1 \, , \vec v_2 )$ depending only upon the quark and anti-quark
coordinates and velocities, valid to second order in their velocities. We
propose $ L_I $ as the Lagrangian describing the long distance interaction of
constituent quarks.


title:
Low $\alpha_{strong}(M_Z)$, Intermediate Scale SUSY SO(10) GUT and Its
  Implications

abstract:
  We show that one of the ways of obtaining consistency between the idea of
supersymmetric grand unification and an apparent low value of
$\alpha_{strong}(M_Z)\simeq .11$ indicated by several low energy experiments is
to have an intermediate scale corresponding to a local $B-L$ symmetry breaking
around the mass scale of $10^{10}$ to $10^{12}$ GeV. We discuss the realization
of this idea within the framework of supersymmetric $SO(10)$ grand unified
theories with spectra of particles derivable from simple superstring-inspired
versions of this model. We then study the $b-\tau$ mass unification within this
class of models and show that due to the influence of new gauge and Yukawa
interactions beyond the intermediate scale, the prediction of the $b$-quark
mass comes out well within the presently accepted values. We also discuss an
un-orthodox class of SUSY models inspired by some theoretical considerations
having two pairs of Higgs doublets at low energy and show that they also can
lead to unification with intermediate scales and low $\alpha_{s}(M_Z)$ as
desired.


title: Mass of scalar resonances beyond the large-$N_c$ limit

abstract:
  Within the Extended Nambu Jona-Lasinio model we analyse the
$1/N_c$-corrections to the leading order result $M_S=2M_Q$ where $M_Q$ is the
constituent quark mass.


title: SCALAR-EMITTING MODES IN DOUBLE-BETA DECAY

abstract:
  The sum-energy spectrum of electrons emitted in double-beta decay is a
well-known diagnostic for the nature of the physics which is responsible for
the decay. Three types of spectra are usually considered when these experiments
are analysed: one each for the standard two-neutrino decay, the neutrinoless
process and a scalar-emitting decay. It has recently been shown that two other
electron spectra can be possible for scalar-emitting modes, in addition to
these traditional three. One of these is softer than the Standard-Model
two-neutrino decay, while the other is intermediate between this and the usual
majoron-emitting spectrum. The models which predict these new spectra are
generically more natural than those which predict the traditional
majoron-emitting spectrum, in that they can accomodate the constraints
following from the steadily improving limits on neutrinoless decay without
requiring the fine-tuning that is endemic to the usual models. This article
reviews the properties of the physics which can produce the new kinds of
electron spectra. (Invited Talk presented to the Workshop on Double Beta Decay
and Related Topics, Trento Italy, April 1995.)


title:
Matching the Low and High Energy Determinations of $\alpha_s(M_z)$ in
  the MSSM

abstract:
  Recent calculations of supersymmetric corrections to the conflicting ratios
$R_b$ and $R_c$ have shown that an alleged discrepancy between the SM
predictions of these observables and the corresponding experimental values can
be cured in the MSSM within a certain region of the parameter space. Here we
show that, in this very same region, also a well-known discrepancy between the
low and high energy determinations of $\alpha_s(M_Z)$ can be disposed of.
Specifically, we find that the lineshape determination of the strong coupling
constant, which in the SM points towards the large central value $\alpha_s(M_Z)
\stackrel{\scriptstyle >}{{ }_{\sim}} 0.125$, can be matched up with the value
suggested by the wealth of low-energy data, namely $\alpha_s(M_Z) \simeq 0.11$,
which is smaller and more in line with the traditional QCD expectations at low
energy. Our approach differs from previous analyses in that we argue that the
desired matching could originate to a large extent from a purely electroweak
supersymmetric quantum effect.


title: Drawing Feynman Diagrams with LaTeX and Metafont

abstract:
  Feynmf is a LaTeX package for easy drawing of professional quality Feynman
diagrams with Metafont (or Metapost). Feynmf lays out most diagrams
satisfactorily from the structure of the graph without any need for manual
intervention. Nevertheless all the power of Metafont (or Metapost) is available
for the most complicated cases.


title: Testing the Standard Model in $B\to K^{(*)} \ell^+\ell^-$

abstract:
  We study the potential of $B\to K^{(*)} \ell^+\ell^-$ decays as tests of the
standard model. After discussing the reliability of theoretical predictions for
the hadronic matrix elements involved, we examine the impact of different new
physics scenarios on various observables. We show that the angular information
in \bks together with the dilepton mass distribution can highly constrain new
physics. This is particularly true in the large dilepton mass region, where
reliable predictions for the hadronic matrix elements can be made with
presently available data. We compare the Standard Model predictions with those
of a Two-Higgs doublet model as well as TopColor models, all of which give
distinct signals in this region.


title: Test of the Equivalence Principle from Neutrino Oscillation Experiments

abstract:
  We consider the hypothesis that neutrino oscillation data can be explained if
the gravitational couplings of (massless or degenerate mass) neutrinos are
flavour non--diagonal, in violation of the equivalence principle. We analyze
the various neutrino oscillation laboratory experimental data including the
recent LSND observations to constrain the relevant parameter space. We find
that there is no allowed region of parameter space which can explain the
existing data, implying that the LSND result cannot be explained by
oscillations of degenerate-mass neutrinos due to equivalence principle
violations.


title:
Angular Distribution and Polarization of Photons in the Inclusive Decay
  $\Lambda_b\to X_s\,\gamma$

abstract:
  We study the angular distribution of photons produced in the inclusive decay
of a polarized $\Lambda_b$, $\Lambda_b\to X_s\,\gamma$, using the technique of
Heavy Quark Effective Theory. Finite non-perturbative corrections are obtained
relative to the free quark decay $b\to s\gamma$. These corrections affect
significantly the intensity and polarization of photons emitted at small angles
relative to the $\Lambda_b$ spin direction.


title: Event Handedness in $e^+e^-$ Annihilation to Three Jets

abstract:
  We discuss rescattering effects that can be measured in $e^+e^-$ annihilation
to three jets through a single gauge boson, by using triple product (``event
handedness'') correlations of the $Z$ ($\gamma^*$) polarization with jet
momenta. The gauge boson polarization may be produced either by polarized beams
or through the natural polarization (left-right asymmetry) of the $Z$. QCD
rescattering does not generate triple product correlations at one loop for
massless quarks. We therefore calculate the QCD contribution for massive
quarks, as well as the contribution of $W$ and $Z$ exchange loops for massless
quarks. Due to various cancellations, the standard model predictions for
triple-product correlations at the $Z$ are very small, making such measurements
potentially sensitive to physics beyond the standard model. For example, the
effects of a new gauge boson that couples only to baryon number may be larger
than the standard model contributions; however the effects would probably still
be too small to effectively constrain it.


title:
Constraining the charged Higgs mass in the left--right symmetric model
  from $b \to s \gamma$

abstract:
  In the context of the left--right symmetric model, the decay $b \rightarrow s
\gamma$ receives contributions from the gauge interactions mediated mainly by
the $W_L$, through $W_L$--$W_R$ mixing and also from the Yukawa interactions of
the charged and the neutral (flavour-changing) scalars (the latter type of
Yukawa interaction has been overlooked in the previous literature). Following
the recent CLEO measurement of the inclusive $b \rightarrow s \gamma$ process
and the measurement of the top-quark mass by the CDF and D0 collaborations, the
parameter space of the left--right symmetric model is more squeezed than
before.


title: Instabilities of Electroweak Strings

abstract:
  We investigate the instabilities of low winding number electroweak strings
using standard numerical techniques of linear algebra. For strings of unit
winding we are able to confirm and extend existing calculations of the unstable
region in the ($m_H/m_W,\sin^2\theta_W$) plane. For strings of higher winding
number we map the unstable regions for the various decay modes.


title:
Second Order QCD Corrections to Scalar and Pseudoscalar Higgs Decays
  into Massive Bottom Quarks

abstract:
  Quark mass effects in ${\cal O}(\alpha_s^2)$ QCD corrections to the decay
rates of intermediate Higgs bosons are studied. The total hadronic rate and the
partial decay rate into bottom quarks are analyzed for the Standard (scalar)
Higgs boson as well as for pseudoscalar Higgs bosons. The calculations of three
different contributions are presented. First, the flavour singlet diagrams
containing two closed fermion loops are calculated for a nonvanishing bottom
mass in the heavy top limit. Their leading contribution, which is of the same
order as the quasi-massless nonsinglet corrections, and the subleading terms
are found. Large logarithms arise due to the separation of the pure gluon final
state from the bottom final states. Second, quadratic bottom mass corrections
originating from nonsinglet diagrams are presented.Third, nonsinglet
corrections induced by virtual heavy top quarks are calculated in leading and
subleading orders. It is demonstrated that, in order $\alpha_s^2$, the first
contribution numerically dominates over the second and the third ones.


title:
Neutrino physics and the mirror world: how exact parity symmetry
  explains the solar neutrino deficit, the atmospheric neutrino anomaly and the
  LSND experiment

abstract:
  Evidence for $\bar \nu_{\mu} \rightarrow \bar \nu_e$ oscillations has been
reported at LAMPF using the LSND detector. Further evidence for neutrino mixing
comes from the solar neutrino deficit and the atmospheric neutrino anomaly. All
of these anomalies require new physics. We show that all of these anomalies can
be explained if the standard model is enlarged so that an unbroken parity
symmetry can be defined. This explanation holds independently of the actual
model for neutrino masses. Thus, we argue that parity symmetry is not only a
beautiful candidate for a symmetry beyond the standard model, but it can also
explain the known neutrino physics anomalies.


title:
The average number of partons per clan in rapidity intervals in parton
  showers

abstract:
  The dependence of the average number of partons per clan on virtuality and
rapidity variables is analytically predicted in the framework of the
Generalized Simplified Parton Shower model, based on the idea that clans are
genuine elementary subprocesses. The results obtained are found to be
qualitatively consistent with experimental trends. This study extends previous
results on the behavior of the average number of clans in virtuality and
rapidity and shows how important physical quantities can be calculated
analytically in a model based on essentials of QCD allowing local violations of
the energy-momentum conservation law, still requiring its global validity.


title:
Novel Structure Function for Photon Fragmentation into a $\Lambda$
  Hyperon and Transverse $\Lambda$ Polarization in Unpolarized
  Electron-Positron Annihilation

abstract:
  The possibility is examined for the inclusive $\Lambda$ in unpolarized
electron-positron annihilation to be transversely polarized. Due to final-state
interactions, there exists a novel structure function $\hat F(z,Q^2)$ for the
inclusive $\Lambda$ hyperon (or any other baryons) production from the
unpolarized time-like photon fragmentation, which makes contribution to the
transverse $\Lambda$ polarization in the unpolarized electron-positron
annihilation.


title: A New Standard Parametrisation of the Cabibbo-Kobayashi-Maskawa Matrix

abstract:
  We propose a new parametrisation of the Cabibbo-Kobayashi-Maskawa Matrix in
which the approximations of the standard parametrisation, $|V_{cb}|\approx
s_{23}$, $|V_{us}|\approx s_{12}$, are promoted to exact results.


title: Heavy meson hyperfine splitting: a complete $1/m_Q$ calculation

abstract:
  We compute the chiral corrections to the hyperfine splittings
$\Delta_D=(m_{D^*_s}-m_{D_s})-(m_{D^{*+}}-m_{D^+})$ and
$\Delta_B=(m_{B^*_s}-m_{B_s})-(m_{B^{*0}}-m_{B^0})$ arising from one-loop
chiral corrections, working in a framework of an effective chiral lagrangian
incorporating chiral, heavy flavour and spin symmetric terms and first order
breaking terms. Among these terms, those responsible for the spin-breaking
difference between the couplings $g_{P^* P^* \pi}$ and $g_{P^* P \pi}$ are
evaluated in the QCD sum rules approach. Their contribution to $\Delta_D$ and
to $\Delta_B$ appears to cancel previously estimated large chiral effects,
giving an estimate in agreement with the experimental data.


title: Chiral Symmetry Breaking via Multi-fermion Green Functions

abstract:
  Previous results on fermion chirality-flipping four-point functions are
extended to $SU(N)$ gauge theories. The problem is purely non-perturbative, and
it is approached by truncating the Schwinger-Dyson hierarchy. The large-$N$
limit also simplifies the problem substantially. The resulting equation is
solved numerically by relaxation techniques and an estimate of the critical
coupling and momentum behavior is obtained. We also comment on the behavior of
chirality-flipping $2n$-point functions for general $n$.


title: Recent Progress on Perturbative QCD Fragmentation Functions

abstract:
  The recent development of perturbative QCD (PQCD) fragmentation functions has
strong impact on quarkonium production. I shall summarize $B_c$ meson
production based on these PQCD fragmentation functions, as well as, the
highlights of some recent activities on applying these PQCD fragmentation
functions to explain anomalous $J/\psi$ and $\psi'$ production at the Tevatron.
Finally, I discuss a fragmentation model based on the PQCD fragmentation
functions for heavy quarks fragmenting into heavy-light mesons.


title:
Precision tests of the Standard Model: evidence for radiative
  corrections and higher order effects

abstract:
  Recent developments in the field of high precision calculations in the
Standard Model are illustrated with particular emphasis on the evidence for
radiative corrections and on the estimate of the theoretical error in
perturbative calculations.


title:
Isovector response function of hot nuclear matter with Skyrme
  interactions

abstract:
  We investigate the role of the effective nucleon-nucleon interaction in the
description of giant dipole resonances in hot nuclei. For this purpose we
calculate the response function of hot nuclear matter to a small isovector
external perturbation using various effective Skyrme interactions. We find that
for Skyrme forces with an effective mass close to unity an undamped zero sound
mode occurs at zero temperature. This mode gives rise in finite nuclei
(calculated via the Steinwedel-Jenssen model) to a resonance whose energy
agrees with the observed value. We find that zero sound disappears at a
temperature of a few MeV, leaving only a broad peak in the dipole strength. For
Skyrme forces with a small value of the effective mass (0.4- 0.5), there is no
zero sound at zero temperature but only a weak peak located too high in energy.
The strength distribution in this case is nearly independent of temperature and
shows small collective effects. The relevance of these results for the
saturation of photon multiplicities observed in recent experiments is pointed
out.


title:
A New Formulation and Regularization of Gauge Theories Using a
  Non-Linear Wavelet Expansion

abstract:
  The Euclidean version of the Yang-Mills theory is studied in four dimensions.
The field is expressed non-linearly in terms of the basic variables. The field
is developed inductively, adding one excitation at a time. A given excitation
is added into the ``background field'' of the excitations already added, the
background field expressed in a radially axial gauge about the point where the
excitation is centered. The linearization of the resultant expression for the
field is an expansion $$ A_\mu(x) \ \cong \ \sum_\alpha \; c_\alpha \;
\psi_\mu^\alpha(x) $$ where $\psi^\alpha_\mu(x)$ is a divergence-free wavelet
and $c_\alpha$ is the associated basic variable, a Lie Algebra element of the
gauge group. One is working in a particular gauge, regularization is simply
cutoff regularization realized by omitting wavelet excitations below a certain
length scale. We will prove in a later paper that only the usual
gauge-invariant counterterms are required to renormalize perturbation theory.
  Using related ideas, but essentially independent of the rest of paper, we
find an expression for the determinant of a gauged boson or fermion field in a
fixed ``small'' external gauge field. This determinant is expressed in terms of
explicitly gauge invariant quantities, and again may be regularized by a cutoff
regularization.
  We leave to later work relating these regularizations to the usual
dimensional regularization.


title: A method for determining CP violating phase $\gamma$

abstract:
  A new way of determining the phases of weak amplitudes in charged $B$ decays
based on SU(3) symmetry is proposed. The CP violating phase $\gamma$ can now be
determined without the previous difficulty associated with electroweak
penguins.


title: Fermion Green functions in non-abelian gauge theories in four dimensions

abstract:
  In this work we study the critical behavior and momentum dependence of
chirality-flipping fermion 4-point functions in non-abelian gauge theories. Our
formalism is based on the Schwinger-Dyson system of equations. Considering the
large-N limit of an SU(N) theory simplifies the problem considerably, showing
us clearly which Green functions can be non-zero and which not. It also allows
us to draw conclusions on chirality-flipping n-point functions for n larger
than four.


title: Search for Dynamical Symmetry Breaking Physics by Using Top Quark

abstract:
  We report first results from the investigation on probing dynamical mechanism
of the electroweak symmetry breaking using top quark. We consider the case
where the top mass originates from a fermion-antifermion pair condensate, which
necessitates (i)strong interaction to cause condensation, and (ii)4-fermi
interaction to give top mass. From the observed top mass and the unitarity
constraint, we obtain, for the 4-fermi interaction (ii), lower bounds for its
strength and upper bounds for its intrinsic new mass scale as we vary the type
of the strong interaction (i). Bethe-Salpeter and Schwinger-Dyson equations are
solved numerically to study the dynamical symmetry breaking effect
semi-quantitatively.


title: Soft Photons from Off-shell Particles in a Hot Plasma

abstract:
  Considering the propagation of off-shell particles in the framework of
thermal field theory, we present the general formalism for the calculation of
the production rate of soft photons and dileptons from a hot plasma. This
approach is illustrated with an electrodynamic plasma. The photon production
rate from strongly interacting quarks in the quark-gluon plasma, which might be
formed in ultrarelativistic heavy ion collisions, is calculated in the
previously unaccessible regime of photon energies of the order of the plasma
temperature within an effective field theory incorporating dynamical chiral
symmetry breaking.


title:
Forms of Relativistic Dynamics, Current Operators and Deep Inelastic
  Lepton-Nucleon Scattering

abstract:
  The three well-known forms of relativistic dynamics are unitarily equivalent
and the problem of constructing the current operators can be solved in any
form. However the notion of the impulse approximation is reasonable only in the
point form. In particular, the parton model which is the consequence of the
impulse approximation in the front form is incompatible with Lorentz
invariance, P invariance and T invariance. The results for deep inelastic
scattering based on the impulse approximation in the point form give natural
qualitative explanation of the fact that the values given by the parton model
sum rules exceed the corresponding experimental quantities.


title: Theory of Brain Function, Quantum Mechanics and Superstrings

abstract:
  Recent developments/efforts to understand aspects of the brain function at
the {\em sub-neural} level are discussed. MicroTubules (MTs) participate in a
wide variety of dynamical processes in the cell, especially in bioinformation
processes such as learning and memory, by possessing a well-known binary
error-correcting code with 64 words. In fact, MTs and DNA/RNA are unique cell
structures that possess a code system. It seems that the MTs' code system is
strongly related to a kind of ``Mental Code" in the following sense. The MTs'
periodic paracrystalline structure make them able to support a superposition of
coherent quantum states, as it has been recently conjectured by Hameroff and
Penrose, representing an external or mental order, for sufficient time needed
for efficient quantum computing. Then the quantum superposition collapses
spontaneously/dynamically through a new, string-derived mechanism for collapse
proposed recently by Ellis, Mavromatos, and myself. At the moment of collapse,
organized quantum exocytosis occurs, and this is how a ``{\em mental order}"
may be translated into a ``{\em physiological action}". Our equation for
quantum collapse, tailored to the MT system, predicts that it takes 10,000
neurons ${\cal O}(1\,{\rm sec})$ to dynamically collapse (process and imprint
information). Different observations/experiments and various schools of thought
are in agreement with the above numbers concerning ``{\em conscious events}".
If indeed MTs, may be considered as the {\em microsites of consciousness}, then
several unexplained properties of consciousness/awareness, get easily
explained, including ``{\em backward masking}", ``{\em referal backwards in
time}". The {\em non-locality} in the cerebral cortex of neurons related to
particular missions, and the related {\em unitary sense of self} as well as


title: Cluster Production with Coalescence and Breakup

abstract:
  The problem of hadronic cluster production in quark-hadron phase transition
in heavy-ion collisions is studied by cellular automata. Previous result on the
scaling behavior is extended to include variation in the drift speed. It is
also shown that coalescence is more important than growth in generating
scaling. A new set of rules is adopted to free the clusters from being rigid.
It is found that the scaling exponent is independent of not only the shapes of
the clusters, but also the probability of breakup of the clusters. The
universality of the scaling behavior is now extended to a wide range of
physical properties characterizing the geometry and dynamics of the phase
transition process.


title: Self-Organized Criticality in Quark-Hadron Phase Transition

abstract:
  The problem of clusters growth in quark-hadron phase transition in heavy-ion
collision is investigated by cellular automata. The system is found to exhibit
self-organized criticality with the distribution of cluster sizes having
universal scaling behavior.


title: Scale Dependence of Polarized DIS Asymmetries

abstract:
  We compare the $Q^{2}$ dependence of the polarized deep inelastic scattering
proton asymmetry, driven by the leading order Altarelli Parisi evolution
equations, to those arising from fixed order $\alpha_{s}$ and $\alpha_{s}^{2}$
approximations. It is shown that the evolution effects associated with gluons,
which are not properly taken into account by the leading order approximation,
cannot be neglected in the analysis of the most recent experimental data.


title: Exclusive Semi-Leptonic Decays of b-Baryons into Protons

abstract:
  We present a QCD-based calculation of the exclusive semileptonic decay
Lambda_b -> p l nu-bar. Using the ideas of Heavy Quark Effective Theory, we
discuss the factorization of the amplitude. Further, resummed Sudakov effects
are put in to ensure a consistent perturbative expansion.


title: Charmonium Production at the Tevatron

abstract:
  We present in this work a study of large-\pt\ charmonium production in
hadronic collisions. We work in the framework of the factorization model of
Bodwin Braaten and Lepage, thereby including the color octet production
mechanism, and extract the values of the necessary nonperturbative parameters
from a comparison with the most recent data from the Fermilab 1.8 TeV $p\bar p$
hadron collider. We extend the calculation to 630 \gev, and compare the results
with data published by the UA1 Collaboration. The global agreement is
satisfactory, indicating that the largest components of the production
mechanisms for charmonium production at high \pt\ have been isolated.


title: Photoproduction of Heavy Quarks

abstract:
  Heavy quarks are copiously produced in two-photon collisions at $e^+e^-$
colliders. The theoretical predictions including QCD radiative corrections are
compared to recent experimental data on $\gamma\gamma$ production of charm
quarks at PETRA, PEP, TRISTAN and LEP. Photoproduction of heavy quarks at HERA
is an important tool to measure the gluon distribution in the proton. New
theoretical results on heavy quark photoproduction at large transverse momenta
are discussed and NLO predictions for inelastic $J/\psi$ photoproduction in the
HERA energy range are given. The sensitivity of the results to the
parametrization of the gluon distribution in the small-$x$ region is
demonstrated.


title: Two Comparative Case Studies of $b$-quark and $c$-quark Physics

abstract:
  We discuss prospects for detecting the two charm-related phenomena of
$D^0$-${\bar D}^0$ mixing and weak radiative decays of $D$ mesons ({\it e.g.}
$D\to K^* + \gamma$). A general update of particle-antiparticle mixing for the
pseudoscalar mesons is presented and the dynamics of mixing is reviewed, with
application especially to the $D^0$-${\bar D}^0$ system. The radiative weak
decays of $B$ mesons is then considered, and the problem of hadronic
uncertainties is reviewed. Finally, the technique of calculating radiative weak
decays for charm mesons is explained.


title: Fragmentation production of heavy quark states

abstract:
  It has recently been noticed that heavy quark ($Q$) and gluon ($g$)
fragmentation to heavy quarkonium states ($Q\bar{Q}$) can be calculated in
perturbative QCD. This technique allows for the inclusion of a subset of higher
order corrections to quarkonium production which dominates at large transverse
momentum. A comparison will be presented between the new calculation of
quarkonium production to the existing data from the Tevatron. In addition some
new results on predictions for double heavy quark baryons at various colliders
will be presented.


title: An Explicit SO(10) x U(1)_F Model of the Yukawa Interactions

abstract:
  We construct an explicit $SO(10) \times U(1)_F$ model of the Yukawa
interactions by using as a guide previous phenomenological results obtained
from a bottom-up approach to quark and lepton mass matrices. The global
$U(1)_F$ family symmetry group sets the textures for the Majorana and generic
Dirac mass matrices by restricting the type and number of Higgs diagrams which
can contribute to each matrix element, while the $SO(10)$ group relates each
particular element of the up, down, neutrino and charged lepton Dirac matrices.
The Yukawa couplings and vacuum expectation values associated with pairs of
{\bf 1,~45, 10,} and {\bf 126} Higgs representations successfully correlate all
the quark and lepton masses and mixings in the scenario incorporating the
nonadiabatic solar neutrino and atmospheric neutrino depletion effects.


title: Predictive SUSY SO(10) model with very low $\tan\beta$

abstract:
  The first fermion family might play a key role in understanding the structure
of flavour: a role of the mass unification point. The GUT scale running masses
$\bar{m}_{e,u,d}$ are rather close, which may indicate an approximate symmetry
limit. Following this observation, we present a new predictive approach based
on the SUSY $SO(10)$ theory with $\tan\beta\sim 1$. The inter-family hierarchy
is first generated in a sector of hypothetical superheavy fermions and then
transfered inversely to ordinary quarks and leptons by means of the universal
seesaw mechanism. The Yukawa matrices are simply parametrized by the small
complex coefficients $\eps_{u,d,e}$ which are related by the $SO(10)$ symmetry
properties. Their values are determined by the ratio of the GUT scale
$M_X\simeq 10^{16}$ GeV to a higher (possibly string) scale $M\simeq
10^{17}-10^{18}$ GeV. The suggested ansatz correctly reproduces the fermion
mass and mixing pattern. By taking as input the masses of leptons and $c$ and
$b$ quarks, the ratio $m_s/m_d$ and the value of the Cabibbo angle, we compute
the $u,d,s$ quark masses, top mass and $\tan\beta$. The top quark is naturally
in the 100 GeV range, but with upper limit $M_t<165$ GeV, while the lower bound
$M_t>160$ GeV implies $m_s/m_d>22$. $\tan\beta$ can vary from 1.4 to 1.7. The
proton decaying $d=5$ operators $qqql$ are naturally suppressed.


title:
Reconciling Present Neutrino Puzzles: Sterile Neutrinos as Mirror
  Neutrinos

abstract:
  We suggest that recent neutrino puzzles that are the solar and atmospheric
neutrino deficits as well as the possible neutrino oscillations reported by the
LSND experiment and the possibility of massive neutrinos providing the hot
component of the cosmological dark matter, can all be naturally explained by
assuming existence of a mirror world described by an ``electroweak'' gauge
symmetry $[SU(2)\times U(1)]'$, with the breaking scale larger by about factor
of 30 than the scale of the standard $SU(2)\times U(1)$ model. An interesting
aspect of this model is that the sterile neutrinos arise from the hidden mirror
sector of the theory and thus their lightness is more natural than in the usual
neutrino mass scenarios. The needed pattern of the neutrino mass matrix in this
model is obtained by assuming a conserved ZKM-type global lepton number $\bar
L=L_e+L_\mu-L_\tau$, which is violated by Planck scale effects. One implication
of our proposal is that bulk of the dark matter in the universe is a warm dark
matter consisting of few KeV mass particles rather than the 100 GeV range
particles of the currently popular cold dark matter scenarios.


title: Sphalerons and Electroweak Strings

abstract:
  We show that the sphaleron energy which identifies with the (instanton)
potential barrier for B-violation is reduced in the presence (background) of an
electroweak Z-string. We also show that for large enough Higgs coupling,
$\lambda$, the sphaleron energy can go negative. For such $\lambda$,
electroweak Z-strings can reduce their energy by accumulating sphaleron bound
states. This further endows them with baryon number. Given our approximation,
the value of $\lambda$ at which this occurs is rather large to be realistic for
the standard electroweak model.


title:
RELATIVISTIC DESCRIPTION OF THE EXCLUSIVE RARE RADIATIVE DECAYS OF B
  MESONS

abstract:
  The exclusive rare radiative $B$-decays are studied in the framework of the
relativistic quark model based on the quasipotential approach in quantum field
theory. The large recoil momentum of the final vector meson allows for the
expansion of the decay form factor in inverse powers of the b-quark mass. This
considerably simplifies the analysis of these decays. The $1/m_b$ expansion is
carried out up to the second order. The form factor of \btok decay is found to
be $F_1^{B\to K^* \gamma}(0)=0.32\pm 0.03 $ and it leads to $BR(B\to K^*\gamma
)= (4.5\pm 1.5) \times 10^{-5}$, which is in agreement with the recent CLEO
data. The form factors of the decays \btorho, \bstophi and \bstok are also
considered. The relation between rare radiative and semileptonic $B$-decays
into light vector meson is discussed.


title:
Next-to-Leading Order Structure Function Evolution at Small x and Large
  Q^2

abstract:
  We show that a unified approach to the perturbative evolution of structure
functions which sums all logarithms of Q^2 and 1/x at leading and
next-to-leading order yields results in full agreement with the 1993 HERA data
for F_2. This makes it possible to determine alpha_s surprisingly accurately
from these data alone.


title: Probing Anomalous Triple Boson Vertices at Future $e^+e^-$ Colliders

abstract:
  We explore the detection potential of the four lepton production processes
$e^{+}e^{-} \rightarrow l^{+} \nu l^{\prime -}\overline{\nu}$ for anomalous
contributions to the triple boson vertices at proposed future high energy
colliders with center-of-mass energies of 500 GeV and 1 TeV. The predicted
bounds are of the order of a few percent for the $CP$-even couplings
$\kappa_{V}$ (V=$\gamma$,Z) at the higher energy; we show that these limits can
be improved by as much as a factor of two through suitable phase space cuts. A
polarized beam facility, with its ability to access helicity information, could
provide constraints on the vertices significantly tighter than those achievable
from an analysis of total cross-section alone. The asymmetries in experimental
observables produced by an explicitly $CP$ violating triple vertex contribution
are seen to be below the expected level of statistical precision of
approximately $1.5 \%$; asymmetries in the individual contributing helicity
amplitudes might however be detectable.


title: FEATURES OF SINGLE LEPTON PRODUCTION AT HADRON COLLIDER

abstract:
  In the Born approximation, as in the next-to-leading order approximation,
Single lepton production $p\bar{p}\rightarrow l^{\pm}\nu X$ at Fermilab
Tevatron is discussed. The effects of non standard model physics ($W'$ -
production) are also considered. It was shown that $2\rightarrow 3$
subprocesses play important role when a high transverse momentum cut on the
lepton is imposed. On the other hand the NLO corrections do not cause
qualitative changes of Born approximation results. The contributions of $W'$
bosons for this signature become more important for large values of
$P_{T}^{cut}$.


title: Universality of infrared renormalons in hadronic cross sections

abstract:
  We discuss the role of infrared renormalons in power corrections to hadronic
cross sections, including their universality. We show how perturbative
renormalon structure arises near kinematic boundaries in the thrust
distribution, the Drell-Yan cross section and radiative B decays. The leading
infrared renormalon in each case is associated with jet evolution. Demanding
that the combination of perturbative and nonperturbative contributions be
well-defined, we infer the form of the leading power corrections to each cross
section. This is at the level $1/Q$ for the thrust distribution and Drell-Yan
process, and $1/m^2$ for B decay. We discuss the universality of $1/Q$
corrections between Drell-Yan and thrust, and conclude that it is approximate,
due to contributions from multijet configurations that may differ in the two
cases.


title: Rare b Decays

abstract:
  Rare b decays provide a unique opportunity to measure Standard Model
parameters and probe beyond the Standard Model. We review here the
experimentalprogress made in measuring these decays, and the importance of
future measurements, including the possible observation of CP violation.


title: D-Meson Mixing in Broken SU(3)

abstract:
  A fit of amplitudes to the experimental branching ratios to two mesons is
used to construct a new estimate of neutral $D$ mixing which includes $SU(3)$
breaking. The result is dominated by the experimental uncertainties. This
suggests that the charm sector may not be as sensitive to new physics as
previously thought and that long-distance calculations may not be useful.


title: Limits on the Neutrino Mass and Mixing Angle from Pion and Lepton Decays

abstract:
  Motivated by a recent rather surprising conclusion based on the 1992 PDG data
on the pion, kaon and lepton decays that if three generations of neutrinos are
assumed to be massive and mixed, the heaviest neutrino, $\nu_3$, could have a
mass in the range, $155~\mbox{MeV} \lsim m_3 \lsim 225~\mbox{MeV}$, we have
analyzed the latest 1995 data on the leptonic decays of pion, $\mu$ and $\tau$
with the assumption that three generations of neutrinos are massive and mixed.
It is shown that when the radiative corrections are included and the constraint
{}from partial decay widths is imposed, the 1995 data are consistent with three
massless neutrinos with no mixing. Various limits on the neutrino mass and
mixing angle implied by the 1995 data are presented together with a critique of
the previous analysis.


title:
Accelerator, reactor and atmospheric neutrino data: a three flavour
  oscillation analysis

abstract:
  We perform a three flavour analysis of the atmospheric, accelerator and
reactor neutrino data from the Kamiokande, LSND and Bugey experiments
respectively. Choosing the values of ${\Delta{m}}^2$ obtained from two flavour
fits of the first two experiments, the allowed ranges of the three generation
mixing angles are determined. The accelerator experiments CHORUS and NOMAD are
found to be most sensitive to regions of the allowed parameter space which
correspond to genuine three generation solutions for the atmospheric neutrino
anomaly.


title: \gamma p \to Vp and \gamma^* p \to Vp

abstract:
  Exclusive vector meson production from real and virtual photons is a good
probe of pomeron physics. In particular, it sheds light on how the soft pomeron
is related to nonperturbative QCD, and how it couples to heavy flavours. It
also raises the question whether there are two pomerons, a soft one and a hard
one.


title:
b -> s +\gamma : A QCD Consistent Analysis of the Photon Energy
  Distribution

abstract:
  The photon energy distribution in the inclusive b -> s+\gamma transitions is
a combination of two components: the first component, soft physics, is
determined by the so called primordial distribution function, while the second
component, perturbative physics, is governed by the hard gluon emission. A
simple ansatz is suggested for the primordial distribution function which obeys
the QCD constraints known so far. We then discuss in detail how the hard gluon
emission affects the energy distribution. An extension of the Sudakov
approximation is worked out incorporating the Brodsky-Lepage-Mackenzie
prescription and its generalizations. We explicitly calculate the marriage of
nonperturbative with perturbative effects in the way required by OPE,
introducing separation scale \mu. A few parameters, such as m_b and \mu_\pi^2
affect the shape of the distribution and, thus, can be determined by matching
to the experimental data. The data, still scarce, while not giving precise
values for these parameters, yield consistency with theory: the current values
of the above parameters lie within experimental uncertainty. On the theoretical
side we outline a method allowing one to go beyond the practical version of
OPE.


title: Splitting Functions in the Light Front Hamiltonian Formalism

abstract:
  In this paper, we have calculated the lowest order splitting functions
occurring in the Altarelli-Parisi equation in the light front hamiltonian
formalism. Two component perturbative LFQCD in light cone gauge is our
guideline and we have used LFTD-approximation for dressed quark and gluon
states.


title: Non-Perturbative Scales in Soft Hadronic Collisions at High Energies

abstract:
  We investigate the role of nonperturbative quark-gluon dynamics in soft high
energy processes. In order to reproduce differential and total cross sections
for elastic proton-proton and proton-antiproton-scattering at high energy and
small momentum transfer it turns out that we need two scales, the gluonic
correlation length and a confinement scale. We find a small gluonic correlation
length, a = 0.2 fm, in accordance with recent lattice QCD results.


title:
Normalization of the Perturbative QCD Corrections for $B\to X_s \,
  \gamma$ Decay

abstract:
  We study the normalization of perturbative QCD corrections to the inclusive
$B \rightarrow X_s \gamma$ decay. We propose to set the renormalization scale
using the Brodsky-Lepage-Mackenzie (BLM) method. In the proposed method the
scale is determined by absorbing the vacuum polarization correction from light
fermions to renormalization scale but not including the anomalous dimensions.
The BLM scale depends in general on the renormalization scheme and the
factorization scale. We find that the BLM scale is insensitive to the
factorization scale. In the heavy-quark potential scheme, we find that the BLM
scale is $\mu_{BLM} \approx (0.315 - 0.334) m_b$ when the factorization scale
varies from $m_b/2$ to $2 m_b$.


title:
Non-Critical String Theory Formulation of Microtubule Dynamics and
  Quantum Aspects of Brain Function

abstract:
  Microtubule (MT) networks, subneural paracrystalline cytosceletal structures,
seem to play a fundamental role in the neurons. We cast here the complicated MT
dynamics in the form of a $1+1$-dimensional non-critical string theory, thus
enabling us to provide a consistent quantum treatment of MTs, including
enviromental {\em friction} effects. We suggest, thus, that the MTs are the
microsites, in the brain, for the emergence of stable, macroscopic quantum
coherent states, identifiable with the {\em preconscious states}. Quantum
space-time effects, as described by non-critical string theory, trigger then an
{\em organized collapse} of the coherent states down to a specific or {\em
conscious state}. The whole process we estimate to take ${\cal O}(1\,{\rm
sec})$, in excellent agreement with a plethora of experimental/observational
findings. The {\em microscopic arrow of time}, endemic in non-critical string
theory, and apparent here in the self-collapse process, provides a satisfactory
and simple resolution to the age-old problem of how the, central to our
feelings of awareness, sensation of the progression of time is generated.


title: Heavy neutrino threshold effects in low energy phenomenology

abstract:
  Right handed neutrinos with mass of ${\cal O} \; (10^{12}-10^{13})$ GeV are
required to implement the see-saw mechanism and generate neutrino masses
capable of playing a role in structure formation.
  Moreover models of fermion masses often relate the Yukawa couplings involving
these neutrinos to the up-quark Yukawa couplings. Here we study the effects of
such couplings on the radiative corrections to quark masses. We find that
$b-\tau$ equality at $M_{GUT}$ may still give the correct $m_b/m_{\tau}$--
ratio at low energies, but only if there is large $\mu-\tau$ mixing in the
charged leptonic sector. We propose specific mass matrix ``textures'' dictated
by a $U(1)$ family symmetry whose structure preserves $m_b=m_{\tau}$ at
$M_{GUT}$. In these schemes, due to the large $\nu_{\mu} - \nu_{\tau}$ mixing,
it is possible to give a simultaneous solution to the solar neutrino deficit
and the atmospheric neutrino problem.


title: A New Physics Source of Hard Gluons in Top Quark Production

abstract:
  We consider the contribution of new strongly interacting sector, with a
characteristic scale of half a TeV, to top quark production at the Tevatron.
The color-octet, isosinglet analog of the $\rho$ meson in this theory is
produced copiously in hadron colliders. If the mass of this resonance is less
than twice the mass of the lightest pseudo-Goldstone bosons, then an important
decay mode could be to the color-octet analog of the $\eta$ and a gluon. The
subsequent decay of this $\eta$ into $\ttbar$ gives rise to top quark events
with a hard gluon.


title:
Constraints on the Proton's Gluon Distribution from Prompt Photon
  Production

abstract:
  We analyze the capability of prompt photon production in pp and pp(bar)
collisions to constrain the gluon distribution of the proton, considering data
from fixed-target experiments as well as collider measurements. Combined fits
are performed to these large-p_T direct gamma cross sections and lepton-proton
deep-inelastic scattering data in the framework of next-to-leading order
perturbative QCD. Special attention is paid to theoretical uncertainties
originating from the scale dependence of the results and from the fragmentation
contribution to the prompt photon cross section.


title:
Two--Loop Electroweak Corrections to the Muon g-2: a new class of
  Hadronic Contributions

abstract:
  We discuss, within the framework of the Standard Model, the calculation of
the two-loop electroweak contributions to the anomalous magnetic moment of the
muon involving triangle fermionic loops of leptons and quarks. Because of the
large ratios of masses involved, these contributions are rather large. The
result we obtain differs from a previous estimate reported in the literature.
The discrepancy originates in the cancellation of anomalies in $SU(3)_c\times
SU(2)_L\times U(1)_Y$, a cancellation that requires the consideration of both
leptons {\it and} quarks within each generation and that had been previously
overlooked.


title: Momentum Sum Rules in QCD for a Photon Target

abstract:
  We deduce momentum sum rules for the parton structure functions of a photon
target. Non-perturbative QCD contribution to the momentum sum rules follows
from conservation of the energy--momentum tensor and it is calculated through
the hadronic part of the photon vacuum polarization operator. The contribution
of the unresolved photon unambiguously follows from gauge invariance,
renormalizability and asymptotic freedom in QCD. We also compare available
parametrizations of parton distribution in a photon with the deduced sum rules.


title: CHIRALLY INVARIANT TRANSPORT EQUATIONS FOR QUARK MATTER

abstract:
  Transport equations for quark matter are derived in the mean field
approximation for the Nambu -- Jona-Lasinio Lagrangian. Emphasis is put on the
chiral limit (zero current quark masses) and the consequences of the chiral
symmetry are investigated in detail. Our approach is based on the spinor
decomposition of the Wigner function. Kinetic equations for the quark densities
and for the spin are derived. We find that the latter is constrained by the
requirement of the axial current conservation.


title:
On the BLM scale-fixing procedure, its generalizations and "genuine"
  higher order corrections

abstract:
  The question of the uniqueness of the Brodsky--Lepage--Mackenzie procedure
for fixing the renormalization scale in perturbative QCD is discussed. It is
shown that the resulting finite order approximants are as ambiguous as the
original truncated perturbative expansions. This inherent ambiguity of the BLM
procedure undermines the recent attempts to define ``genuine'' higher order
perturbative corrections.


title:
Top Production in Hadron-Hadron Collisions and Anomalous Top-Gluon
  Couplings

abstract:
  We discuss the influence of anomalous tbar-t-G couplings on total and
differential tbar-t production cross sections in hadron-hadron collisions. We
study in detail the effects of a chromoelectric and a chromomagnetic dipole
moment, d' and \mu', of the top quark. In the d'-\mu' plane, we find a whole
region where the anomalous couplings give a zero net contribution to the total
top production rate. In differential cross sections, the anomalous moments have
to be quite sizable to give measurable effects. We estimate the values of d'
and \mu' which are allowed by the present Tevatron experimental results on top
production. A chromoelectric dipole moment of the top violates CP invariance.
We discuss a simple CP-odd observable which allows for a direct search for CP
violation in top production.


title:
Cross Sections for Charm Production in $ep$ Collisions: Massive versus
  Massless Scheme

abstract:
  The next--to--leading order inclusive cross section for large-$p_\perp$
photoproduction of charm quarks at HERA is calculated in two different
approaches. In the first approach the charm quarks are treated as massive
objects which are strictly external to the proton and the photon while in the
second approach the charm mass is neglected and the $c$ quark is assumed to be
one of the active flavours in the proton and photon structure functions. We
present single-inclusive distributions in transverse momentum and rapidity
including direct and resolved photons. The cross section in the massless
approach is found to be significantly larger than in the massive scheme. The
deviation originates from several contributions which are disentangled. We
argue that large-$p_\perp$ photoproduction of charm quarks at HERA will be
sensitive to the charm content of the photon structure function.


title:
A comment on the anomalous $Zt\bar t$ couplings and the $Z\to b\bar b$
  decay

abstract:
  By reanalyzing the influence of the anomalous $Z\bar t t$ couplings on the
$Z\rightarrow b\bar b$ decay process, we pointed out the ambiguity in the
conventional treatment of the effective Lagrangian approach, because of the
possible existence of large contributions given by constant terms beyond the
leading cutoff dependent term.


title: ANTIGRAVITATING BUBBLES

abstract:
  We investigate the gravitational behavior of spherical domain walls (bubbles)
arising during the phase transitions in the early Universe. In the thin-wall
approximation we show the existence of the new solution of Einstein equations
with negative gravitational mass of bubbles and the reversed direction of time
flow on the shell. This walls exhibit gravitational repulsion just as the
planar walls are assumed to do. The equilibrium radius and critical mass of
such objects are found for realistic models.


title: BARYON AND TIME ASYMMETRIES OF THE UNIVERSE

abstract:
  This paper is devoted to the investigation of connection between two apparent
asymmetries of the nature --- time-asymmetry and Baryon Asymmetry of the
Universe (BAU). The brief review of this subjects is given. We consider the
particle behavior in curved space-time and the possibility of $T$- and
$CPT$-violation by the universe expansion. If these symmetries are violated we
can dispens with the nonequilibrium condition which is usualy considered as the
one of necessary ingredients for BAU-generation. Such mechanism of GUT-scale
baryogenesis can provide the observed value of baryon asymmetry. We show this
on the example of minimal $SU(5)$ model which usually fails to explain the
observed BAU withought taking into account gravitational effects. Predominance
of matter over antimatter and the cosmological arrow of time (the
time-direction in which the Universe expands) seem to be connected facts and,
possibly, BAU is the one of observable facts of $CPT$-violation in nature.


title: ESTIMATION OF THE MEAN ENERGY OF MUONS IN MULTILAYER DETECTORS

abstract:
  The technique of muon mean energy determination in multilayer detectors is
developed. The mean energy is measured by means of average small bursts $m$
i.e. the number of electrons and positrons generated by muons in the detecting
layers of device via three basic processes --- creation of $e^+e^-$ pairs,
$\delta$-electrons and bremsestrahlung. The accuracy of the method is
considered.
  Key words: muon energy, multilayer detectors.


title:
NEW MECHANISM OF $CP$-VIOLATION IN THE MODELS OF ELECTROWEAK
  BARYOGENESIS

abstract:
  The new source of $CP$-violation in the frames of "charge transport"
mechanism of electroweak baryogenesis is investigated. The consideration is
based on the assumption that $C$ and $CP$ need not be violated at the same
place, and on the fact that in the case of nonpolarized flux of fermions
falling nonperpendicularily on the phase-separating domain wall the transmitted
flux will be polarized (i.e. $P$ and $CP$ are violated). Sphaleron processes
can convert the ($P$ and $CP$)-asymmetric state into ($C$ and $CP$)-asymmetric
one. We argue that the value of $CP$-violation in such mechanism can explain
the observed value of Baryon Asymmetry of the Universe even in the frames of
the Minimal Standard Model.


title: Gluino-Pair Production at the Tevatron

abstract:
  The next-to-leading order QCD corrections to the production of gluino pairs
at the Tevatron are presented in this paper. Similar to the production of
squark-antisquark pairs, the dependence of the cross section on the
renormalization/factorization scale is reduced considerably by including the
higher-order corrections. The cross section increases with respect to the
lowest-order calculation which, in previous experimental analyses, had been
evaluated at the scale of the invariant energy of the partonic subprocesses.


title: Charm Production and High Energy Atmospheric Muon and Neutrino Fluxes

abstract:
  Production of muons and neutrinos in cosmic ray interactions with the
atmosphere has been investigated with Monte Carlo models for hadronic
interactions. The resulting conventional muon and neutrino fluxes (from $\pi$
and $K$ decays) agree well with earlier calculations, whereas our prompt fluxes
from charm decays are significantly lower than earlier estimates. Charm
production is mainly considered as a well defined perturbative QCD process, but
we also investigate a hypothetical non-perturbative intrinsic charm component
in the proton. The lower charm rate implies better prospects for detecting very
high energy neutrinos from cosmic sources.


title: On $Z$ and $Z + jet$ Production in Heavy Ion Collisions

abstract:
  Z+jet production in heavy ion collisions at the LHC is proposed as a possible
probe of the properties of the dense hadronic matter. It is shown that the
accuracy of this measurement with general purpose LHC detectors and under
realistic experimental conditions can be high enough. It is argued also that
$Z$-boson production and subsequent leptonic decay is a good reference process
for this measurement, as well as for the QCD process of high $P_T$ jet pair
production.


title: Charm Production via Fragmentation

abstract:
  The next-to-leading open charm production in $\gamma p$ collisions is
calculated within the Perturbative Fragmentation Functions formalism, to allow
resummation of $\as\log(\pt^2/m^2)$ terms. In the large $\pt$ region $(\pt >
m)$ the result is consistent with the fixed order NLO calculation, small
discrepancies being found for very large $\pt$ and at the edge of phase space.
The two approaches differ in the definition and the relative contribution of
the direct and resolved terms, but essentially agree on their sum. The
resummation is found to lead to a reduced sensitivity to the choice of the
renormalization/factorization scale.


title: Light-Front View of The Axial Anomaly

abstract:
  Motivated by an apparent puzzle of the light-front vacua incompatible with
the axial anomaly, we have considered the two-dimensional massless Schwinger
model for an arbitrary interpolating angle of the quantization surface. By
examining spectral deformation of the Dirac sea under an external electric
field semiclassically, we have found that the axial anomaly is quantization
angle independent. This indicates an intricate nontrivial vacuum structure
present even in the light-front limit.


title: t-channel Approach to Reggeon Interactions in QCD

abstract:
  Starting from the multi-Regge effective action for high-energy scattering in
QCD a $t$-channel approach can be developed which is similar to the approach by
White based on general Regge arguments. The BFKL kernel of reggeized gluon
interaction, contributions to the $2 \rightarrow 4 $ reggeized gluon vertex
function and the one-loop correction to the BFKL kernel are considered. The
conditions are discussed under which this approach can provide a simple
estimante of the next-to-leading logarithmic corrections to the BFKL
perturbative pomeron intercept.


title:
The Spectrum of the Nucleons and the Strange Hyperons and Chiral
  Dynamics

abstract:
  The spectra of the nucleons, $\Delta$ resonances and the strange hyperons are
well described by the constituent quark model if in addition to the harmonic
confinement potential the quarks are assumed to interact by exchange of the
$SU(3)_F$ octet of pseudoscalar mesons, which are the Goldstone bosons
associated with the hidden approximate chiral symmetry of QCD. In its $SU(3)_F$
invariant approximation the pseudoscalar exchange interaction splits the
multiplets of $SU(6)_{FS}\times U(6)_{conf}$ in the spectrum to multiplets of
$SU(3)_F\times SU(2)_S\times U(6)_{conf}$. The position of these multiplets
differ in the baryon sectors with different strangeness because of the mass
splitting of the pseudoscalar octet and the different constituent masses of the
u,d and s quarks that breaks $SU(3)_F$ flavor symmetry. A description of the
whole spectrum, to an accuracy of $\simeq$ 4\% or better, is achieved if one
matrix element of the boson interaction for each oscillator shell is extracted
from the empirical mass splittings. The ordering of the positive and negative
parity states moreover agrees with the empirical one in all sectors of the
spectrum. A discussion of the conceptual basis of the model and its various
phenomenological ramifications is presented.


title: Semileptonic $B\to D$ and $B\to D^*$ Decays from the Lattice

abstract:
  We obtain form factors relevant for semileptonic $B\to D$ and $B\to D^*$
decays from a quenched lattice QCD calculation. Our results enable us to test
Heavy-Quark Symmetry, determine the Isgur-Wise function as well as obtain the
Cabibbo-Kobayashi-Maskawa (CKM) matrix element $V_{cb}$ from a measurement, by
the CLEO collaboration, of the differential decay rate for semileptonic $B\to
D^*$ decays. We find that the Isgur-Wise function has a slope of
$-(0.9\er{4}{4})$ at zero recoil and that
$|V_{cb}|K(1)=0.037\er{1}{1}\er{4}{2}\; (0.99/(1+\b_{A_1}(1)))$, where the
first set of errors is due to experimental uncertainties and the second to our
errors on $\rho^2$. Here $K(1)$ and $\b_{A_1}(1)$ denote respectively power and
radiative corrections at zero recoil.


title: STABILITY OF Z-STRINGS IN STRONG MAGNETIC FIELDS

abstract:
  We show that the Z-strings of the standard electroweak theory can be
stabilized by strong external magnetic fields, provided that $\beta^{1/2}
\equiv M_H/M_Z\leq 1$, where $M_H$ and $M_Z$ are the Higgs and Z masses. The
magnetic fields needed are larger than $\beta^{1/2} B_c$ and smaller than
$B_c$, where $B_c\equiv M^2_W/e$ is the critical magnetic field which causes
W-condensation in the usual broken phase vacuum. If such magnetic fields were
present after the electroweak transition, they would stabilize strings for a
period comparable to the inverse Hubble rate at that time. Pair creation of
monopoles and antimonopoles linked by segments of string is briefly considered.


title: Solar Models with Helium and Heavy Element Diffusion

abstract:
  Heavy element and helium diffusion are both included for the first time in
this series of papers on precise solar models, along with improvements in the
input data for nuclear reaction rates, the solar luminosity, the solar age,
heavy element abundances, radiative opacities, helium and metal diffusion
rates, and neutrino interaction cross sections. The calculated neutrino event
rates, including all of the improvements, are $9.3_{-1.4}^{+1.2}$ SNU for the
\hbox{$^{37}$Cl} experimentand $137_{-7}^{+8} $ SNU for the \hbox{$^{71}$Ga}
experiments. The calculated flux of \hbox{$^{7}$Be} neutrinos is
$5.1(1.00_{-0.07}^{+0.06}) \times 10^{9}~{\rm cm^{-2}s^{-1}}$ and the flux of
${\rm ^8B}$ neutrinos is $6.5 (1.00_{-0.17}^{+0.14})\times 10^{6}~{\rm
cm^{-2}s^{-1}}$. The present-day surface helium abundance of the model is $Y_s
= 0.247$, in agreement with the helioseismological measurement of $Y_s = 0.242
\pm 0.003$ determined by Hernandez and Christensen-Dalsgaard (1994). The
computed depth of the convective zone is \hbox{$R = 0.712~ R_{\odot}$} in
agreement with the observed value determined from $p$-mode oscillation data of
\hbox{$R = 0.713 \pm 0.003~ R_{\odot}$} found by Christensen-Dalsgaard {\it et
al.}~(1991). Solar models that do not include diffusion disagree with the
helioseismology measurements. Although the present results increase the
predicted event rate in the four operating solar neutrino experiments by almost
$1\sigma$ (theoretical uncertainty), they only slightly increase the difficulty
of explaining the existing experiments with standard physics (i.e., by assuming
that nothing happens to the neutrinos after they are created in the center of
the sun).


title: Renormalon contributions to \delta\rho

abstract:
  Leading QCD vacuum polarization contributions to the electroweak parameter
$\delta\rho$ are evaluated numerically using several different prescriptions
for the gluon self-energy. Simple theoretical estimates of the asymptotic
behavior are given. The results show a significant contribution from the
leading infrared renormalons when $\delta\rho$ is expressed in terms of the
top-quark pole mass and its absence when the $\msbar$ running mass is employed.
The calculations are applied to estimate higher order QCD contributions to
$\delta\rho$.


title: Baryon Isovector Electric Properties and the Large N_c and Chiral Limits

abstract:
  A model independent calculation is given for the nucleon isovector electric
charge radius which is valid in the limit $N_c \rightarrow \infty$, $m_\pi
\rightarrow 0$, $N_c m_\pi$ fixed. This expression reduces to that of the
Skyrme model in the limit $N_c m_{\pi} \rightarrow \infty$.


title: The Unified Minimal Supersymmetric Model with Large Yukawa Couplings

abstract:
  The consequences of assuming the third-generation Yukawa couplings are all
large and comparable are studied in the context of the minimal supersymmetric
extension of the standard model. General aspects of the RG evolution of the
parameters, theoretical constraints needed to ensure proper electroweak
symmetry breaking, and experimental and cosmological bounds on low-energy
parameters are presented. We also present complete and exact semi-analytic
solutions to the 1-loop RG equations. Focusing on SU(5) or SO(10) unification,
we analyze the relationship between the top and bottom masses and the
superspectrum, and the phenomenological implications of the GUT conditions on
scalar masses. Future experimental measurements of the superspectrum and of the
strong coupling will distinguish between various GUT-scale scenarios. And if
present experimental knowledge is to be accounted for most naturally, a
particular set of predictions is singled out.


title:
Anomalous Couplings in Single Higgs Production through $\gamma\gamma$
  Collisions

abstract:
  We show that single Higgs production in $\gamma\gamma$ collisions through
laser backscattering provides the best way to look for New Physics (NP) effects
inducing anomalous Higgs couplings. Our analysis is based on the four $dim=6$
operators $\O_{UB}$, $\O_{UW}$, $\ol{\O}_{UB}$ and $\ol{\O}_{UW}$ which
describe New Physics effects in this sector. Using the Higgs production rate we
establish observability limits for the couplings of the aforementioned
operators at a level of $10^{-3}$, which means establishing lower bounds on the
scale of NP of the order 30 to 200 TeV. Higgs branching ratios, especially the
ratio $\Gamma(H\to\gamma\gamma)/\Gamma (H\to\gamma Z)$, are shown to provide
powerful ways to disentangle the effects of the various operators.


title:
Signatures of anomalous coupling in boson pair production through \gamma
  \gamma collisions

abstract:
  We discuss possible New Physics (NP) effects on the processes $\gamma\gamma
\to W^+W^-$, $ZZ$, $Z\gamma$, $\gamma\gamma$, $HH$ which are observable in
$\gamma\gamma$ collisions. Such collisions may be achieved through laser
backscattering at a high energy $e^+e^-$ linear collider. To the extent that no
new particles will be directly produced in the future colliders, it has already
been emphasized that the new physics possibly hidden in the bosonic
interactions, may be represented by the seven $dim=6$ operators $\O_W$,
$\O_{B\Phi}$, $\O_{W\Phi}$, $\O_{UB}$, $\O_{UW}$, $\ol{\O}_{UB}$ and
$\ol{\O}_{UW}$ (the last two ones being CP-violating). In this paper, we show
that the above processes are sensitive to NP scales at the several TeV range,
and we subsequently discuss the possibility to disentangle the effects of the
various operators.


title: NEW FORMULAS RELATING THE MASSES OF SOME BARYONS AND MESONS

abstract:
  Sum rules relating the masses of ground-state baryons and mesons are obtained
in a constituent quark model. The interaction is assumed to be independent of
quark spins except for a spin-dependent part that can be treated as a
perturbation. Where data are available, the sum rules agree with experiment to
better than 1\%.


title: Perturbative evaluation of the eigenvalues of the Herbst Hamiltonian

abstract:
  We reconsider the well-known and long-debated problem of the calculation of
the eigenvalues of the Herbst Hamiltonian 2\sqrt{p^2 +m^2} - \kappa/r. We give
a formulation of the problem that allows, for the first time, a perturbative
evaluation of the eigenvalues for any n and l, and in principle up to any order
in \kappa via standard Kato perturbation theory. We present the evaluation of
the energy of the n=1 and n=2 states up to \kappa^6, confirming the result
previously obtained by Le Yaouanc et al. with a completely different technique.
Moreover we give the n=2, l=1 level, which is new. Discussion of the results
and comparison with previous findings are given at the end.


title: Single-top-quark production via q qbar -> t bbar

abstract:
  We consider single-top-quark production via the weak process $q\bar q to
t\bar b$ at hadron colliders. This process may provide the best measurement of
the magnitude of the Cabbibo-Kobayashi-Maskawa matrix element $V_{tb}$. We show
that a signal can potentially be observed at the Fermilab Tevatron with 3
$fb^{-1}$ of integrated luminosity. In contrast, the signal is masked at the
CERN Large Hadron Collider by top-quark pair production and single-top-quark
production via $W$-gluon fusion.


title: Radiative Corrections to pi_{l2} and K_{l2} Decays

abstract:
  We report on our reexamination of the radiative corrections to $\pi_{l2}$ and
$K_{l2}$ decays. We perform a matching calculation, using a specific model with
vector meson dominance in the long distance part and the parton model in the
short distance part. By considering the dependence on the matching scale and on
the hadronic parameters, and by comparing with model independent estimates, we
scrutinize the model dependence of the results. For the pseudoscalar meson
decay constants, we extract the values $f_\pi = (92.1 \pm 0.3)\,\mbox{MeV}$ and
$f_K = (112.4 \pm 0.9) \, \mbox{MeV}$. For the ratios $R_\pi$ and $R_K$ of the
electronic and muonic decay modes, we predict $R_\pi = (1.2354 \pm 0.0002)
\cdot 10^{-4}$ and $R_K = (2.472 \pm 0.001) \cdot 10^{-5}$.