title: Review on CP Violation

abstract:
  A phenomenological description of the neutral K and B meson systems is
presented. The situation of the current CP violation experiments is described
and a detailed discussion of their results is given, followed by some future
prospects.


title: Model-Independent Global Constraints on New Physics

abstract:
  Using effective-lagrangian techniques we perform a systematic survey of the
lowest-dimension effective interactions through which heavy physics might
manifest itself in present experiments. We do not restrict ourselves to special
classes of effective interactions (such as `oblique' corrections). We compute
the effects of these operators on all currently well-measured electroweak
observables, both at low energies and at the $Z$ resonance, and perform a
global fit to their coefficients. Despite the fact that a great many operators
arise in our survey, we find that most are quite strongly bounded by the
current data. We use our survey to systematically identify those effective
interactions which are {\it not} well-bounded by the data -- these could very
well include large new-physics contributions. Our results may also be used to
efficiently confront specific models for new physics with the data, as we
illustrate with an example.


title: Mesons in the quenched approximation at low temperature

abstract:
  We use an effective low energy field theory to describe the coupling between
glueballs and mesons as an analog of the quenched approximation in lattice QCD.
This allows us to study the temperature dependence of mesonic screening masses
at temperatures below the deconfinement phase transition.


title: Cosmological Phase Transitions

abstract:
  Physical processes related to cosmological first-order phase transitions are
discussed and reviewed in this introductory part of dissertation. I first
describe cosmological phase transitions on a general level, concentrating on
bubble nucleation, phase change, and related phenomena. I point out that
especially the onset of a cosmological phase transition shows a universal
behavior. Then I discuss the electroweak and quark-hadron phase transitions
from a more phenomenological point of view, and present a partially
quantitative description of the different events that is believed to have taken
place during these two cosmological transitions.


title: Area Decay Law Implementation for Quark String Fragmentation

abstract:
  We apply the Area Decay Law (ADL) straightforwardly to simulate a quark
string hadronization and compare the results with the explicit analytic
calculations. We show that the usual "inclusive" Monte--Carlo simulations do
not correspond to the ADL because of two mistakes: not proper simulation of
two--dimensional probability density and lack of an important combinatorial
factor in a binary tree simulation. We also show how to simulate area decay law
"inclusively" avoiding the above--mentioned mistakes.


title: Galilean Limit of Equilibrium Relativistic Mass Distribution

abstract:
  The low-temperature form of the equilibrium relativistic mass distribution is
subject to the Galilean limit by taking $c\rightarrow \infty .$ In this limit
the relativistic Maxwell-Boltzmann distribution passes to the usual
nonrelativistic form and the Dulong-Petit law is recovered.


title:
Aspects of the electroweak phase transition in the Minimal
  Supersymmetric Standard Model

abstract:
  We study the finite-temperature effective potential of the Minimal
Supersymmetric Standard Model in the full (mA, tan(beta)) parameter space. As
for the features of the electroweak phase transition, we identify two possible
sources of significant differences with respect to the Standard Model: a stop
sector with little supersymmetry breaking makes the phase transition more
strongly first-order, whereas a light CP-odd neutral boson weakens its
first-order nature. After including the leading plasma effects, T=0 radiative
corrections due to top and stop loops, and the most important experimental
constraints, we find that the danger of washing out any baryon asymmetry
created at the electroweak scale is in general no less than in the Standard
Model.


title: CP Violation

abstract:
  An overview of the phenomenology of CP violation is presented. The Standard
Model mechanism of CP violation and its main experimental tests, both in the
kaon and bottom systems, are discussed. (Lectures given at the 1993 Trieste
Summer School and at the Escuela Latinoamericana de Fisica, ELAF'93,
Argentina).


title: Quark Structure and Weak Decays of Heavy Mesons

abstract:
  We investigate the quark structure of D and B mesons in the framework of a
constituent quark model. To this end, we assume a scalar confining and a one
gluon exchange (OGE) potential. The parameters of the model are adopted to
reproduce the meson mass spectrum. From a fit to ARGUS and CLEO data on B->D*lv
semileptonic decay we find for the Cabbibo Kobayashi Maskawa matrix element
Vcb=0.036+-0.003. We compare our form factors to the pole dominance hypothesis
and the heavy quark limit. For non-leptonic decays we utilize factorization and
for B->D*X decays we find a1 = 0.96+-0.05, and a2=0.31+-0.03.


title: Cumulant to Factorial Moment Ratio and Multiplicity Distributions

abstract:
  The ratio of cumulant to factorial moments of multiplicity distribu- tions
has been calculated for e+e- and hh data in a wide range of energies. As a
function of the rank it exhibits a regular behaviour with a steep descent and
two negative minima. This behaviour is not accounted for by NBD, that leads to
a monotonically decreasing positive-defined ratio. A rough comparison with QCD
predictions is done: data cannot be accounted for by LLA nor by DLA; only some
next-to-next to leading predictions are in qualitative agreement with them.
Such features being appropriate for hard processes and high energies, it is a
surpri- se to find them not only in e+e- annihilation, but also in soft hh
collisions.


title:
Contribution of Quark-Mass-Dependent Operators to Higher Twist Effects
  in DIS

abstract:
  We look at the contribution of Quark-Mass-dependent twist-4 operators to the
second moments of spin averaged structure functions and the Bjorken sum rule.
Its contribution is non-negligible in the former case due to large Wilson
coefficients. We also discuss the values of the twist- 4 spin-2 nucleon matrix
element within present experimental constraints.


title:
Effects of non-standard couplings, radiative corrections and neutrino
  masses on the lepton spectrum in $\mu$ and $\tau$ decays

abstract:
  We investigate the combined effect of neutrino masses and non-standard
couplings on the various lepton spectra in $\mu$ and $\tau$ decays. We
emphasize the energy spectra of the neutrinos, which can be measured in the new
KARMEN experiment and hence will yield novel information on deviations from the
$V-A$ structure. To constrain these couplings, QED radiative corrections have
to be taken into account. We evaluated them and found small corrections to the
neutrino spectra.


title: $B_c$ Meson Productions Via Induced Gluon Fragmentation

abstract:
  Gluons cannot directly fragment into $B_c$ mesons until at order
$\alpha_s^3$. However, the Altarelli-Parisi evolution of the $\bar b$-quark
fragmentation functions $D_{\bar b \to B_c}(z)$ and $D_{\bar b \to B_c^*}(z)$
from the heavy quark mass scales up to the collider energy scale $Q$ can induce
the gluon fragmentation functions $D_{g \to B_c}(z)$ and $D_{g \to B_c^*}(z)$,
respectively, through the gluon splitting $g\to \bar b$ at the order
$\alpha_s^3 \, {\rm log} (Q/m_{b,c})$. We will determine these induced gluon
fragmentation functions. The $B_c$ meson productions due to the induced gluon
fragmentation will be evaluated and compared to the productions by the direct
$\bar b$-quark fragmentation. The contribution from the induced gluon
fragmentation is found to be a significant portion of the total $B_c$ and
$B_c^*$ meson productions, and therefore cannot be ignored.


title: Detecting the Technirho in Technicolor Models with Scalars

abstract:
  We consider the detection of the technirho in technicolor models that include
a weak scalar doublet. In these models, the scalar develops a vacuum
expectation value when the technifermions condense, and fermion masses are
generated through Yukawa couplings, as in the standard model. Unlike ordinary
technicolor models, the technicolor scale is generally smaller than the
electroweak scale, and the entire technicolor spectrum is shifted to lower
energies. In addition, the technifermions can develop large `current' masses
from the scalar's vev, so that the technicolor spectrum does not necessarily
look like a scaled-up version of ordinary QCD. We discuss the collider
signatures for the technirho in these models in the limit that the technirho is
light. Although we focus mostly on the production and detection of the
technirho in hadron colliders, we also discuss a peculiar limit in which the
technirho may be light enough to be seen at LEP II.


title:
Corrections to Chiral Dynamics of Heavy Hadrons: SU(3) Symmetry
  Breaking, (with some minor corrections)

abstract:
  In previous publications we have analyzed the strong and electromagnetic
decays of heavy mesons and heavy baryons in a formalism which incorporates
heavy-quark and chiral symmetries. There are two possible symmetry-breaking
effects on the chiral dynamics of heavy hadrons: the finite-mass effects from
light quarks and the $1/ m_Q$ corrections from heavy quarks. In the present
paper, chiral-symmetry-breaking effects are studied and applications to various
strong and radiative decays of heavy hadrons are illustrated. SU(3) violations
induced by chiral loops in the radiative decays of charmed mesons and charmed
baryons are compared with those predicted by the constituent quark model. In
particular, available data for $D^*$ decays favor values of the parameters in
chiral perturbation theory which give predictions for $D^*$ decays close to the
quark model results except for the $D^{*+}_s$. Implications are discussed.


title: What Can be Learnt from the New Ua4/2 Data

abstract:
  A careful analysis of the new data of the UA4/2 collaboration reveals that
these data give an essentially large value of the $\rho = Re T(s,t)/Im(s,t)$
that does not contradict the early UA4 experiment. There is the reason to think
also that this experiment reveals for the first time a real possibility of the
existence of the spin-flip amplitude at superhigh energies in the range of
small transfer momenta.


title:
QCD Corrections and the Endpoint of the Lepton Spectrum in Semileptonic
  B Decays

abstract:
  Recently, Neubert has suggested that a certain class of nonperturbative
corrections dominates the shape of the electron spectrum in the endpoint region
of semileptonic $B$ decay. Perturbative QCD corrections are important in the
endpoint region. We study the effects of these corrections on Neubert's
proposal. The connection between the endpoint of the electron spectrum in
semileptonic $B$ decay and the photon spectrum in $b\rightarrow s\gamma$ is
outlined.


title: Low--Energy Theorems for Weak Pion Production

abstract:
  We derive novel low--energy theorems for single pion production off nucleons
through the isovector axial current. We find that the $k^2$-dependence of the
multipole $L_{0+}^{(+)}$ at threshold is given by the nucleon scalar form
factor, namely $\sigma(k^2-M_\pi^2 ) /(3 \pi M_\pi F_\pi )$. The relation to
PCAC results for soft pions including electroweak form factors is also
clarified.


title: Testing Anomalous $W$ Couplings in $e^- e^-$ Collisions

abstract:
  We analyze the influence of anomalous gauge couplings in the reaction $e^- \:
e^- \longrightarrow e^- \: W^- \: \nu_e$ at a 500 GeV linear collider. The
limits imposed by this process on deviations from the standard model of
electro-weak interaction, are competitive with those inferred from other high
energy experiments. Furthermore, the allowed domain in the parameter space is
quite different, and hence such an experiment would more than complement the
other direct searches.


title: Quantum theory for the Standard Model

abstract:
  These lectures present some basic facts in field theory necessary to
understand the quantum theory of the Standard Model of weak and electromagnetic
interactions.


title: Hard diffraction and proton spin problem

abstract:
  It is shown, that the hard component of quarks distribution functions induced
by instantons gives the essential contribution to hard diffractive processes.
We predict large polarization effects in these processes.


title: Analysis of the Photon Spectrum in Inclusive $B\to X_s\,\gamma$ Decays

abstract:
  Using a combination of the operator product and heavy quark expansions, we
resum the leading nonperturbative contributions to the inclusive photon
spectrum in $B\to X_s\,\gamma$ decays. The shape of the spectrum is determined
by a universal structure function, which describes the distribution of the
light-cone momentum of the $b$-quark inside the $B$-meson. The moments of this
function are proportional to forward matrix elements of higher-dimension
operators. As a by-product, we obtain the bound $\lambda_1<0$ for one of the
parameters of the heavy quark effective theory. The integral over the $B\to
X_s\,\gamma$ structure function is related to the shape function that governs
the fall-off of the lepton spectrum close to the endpoint in $B\to
X_u\,\ell\,\bar\nu$ decays. A measurement of the photon spectrum in rare
$B$-decays can therefore help to obtain a model-independent determination of
$V_{ub}$.


title:
Generation non-universality and flavor changing neutral currents in the
  331 model

abstract:
  The 331 model, an extension of the standard electroweak theory to
$SU(3)_L\times U(1)_X$, naturally predicts three families of quarks and leptons
via the requirement of anomaly cancellation. This is accomplished by making one
of the quark families transform differently from the other two, thus leading to
flavor changing neutral currents. Using experimental input on neutral meson
mixing, we show that the third family must be the one that is singled out, at
least up to small family mixing. We additionally describe a convenient way to
parametrize the new mixing matrix that plays a role in the gauge interactions
of the ordinary quarks with the new 331 quarks.


title:
On validity of perturbative quantization of the breathing mode in the
  Skyrme model

abstract:
  We present a detailed discussion of the breathing mode quantization in the
Skyrme model and demonstrate that the chiral angle of the hedgehog soliton is
strongly affected by the breathing motion.


title: Single-Lepton Top Signals with a b-Tag at the Tevatron

abstract:
  Events with a leptonic W-decay plus jets should contain top-quark signals,
but a QCD W+jets background must be separated. We compare transverse
W-momentum, jet multiplicity, and b-tagging separation criteria, and find that
the main background after tagging comes from mistagging. We illustrate how to
extract the mass m_t via event reconstructions and how to confirm signal purity
by lepton angular distributions.


title:
Constraints on left-right symmetric models from the process $b
  \rightarrow s \gamma$

abstract:
  In left-right symmetric models, large contributions to the decay amplitude $b
\rightarrow s+ \gamma$ can arise from the mixing of the $W_L$ and $W_R$ gauge
bosons as well as from the charged Higgs boson. These amplitudes are enhanced
by the factor $\mt/\mb$ compared to the contributions in the standard model. We
use the recent CLEO results on the radiative $B$ decay to place constraints on
the $W_L-W_R$ mixing angle $\zeta$ and the mass of the charged Higgs boson
$m_{H^\pm}$. Significant departures from the standard model predictions occur
when $|\zeta| > 0.003$ and/or when $m_{H^\pm} < $ a few TeV.


title: Top and Higgs Masses in Dynamical Symmetry Breaking

abstract:
  A model for composite electroweak bosons is re-examined to establish
approximate ranges for the initial predictions of the top and Higgs masses.
Higher order corrections to this $4$-fermion theory at a high mass scale where
the theory is matched to the Standard Model have little effect, as do wide
variations in this scale. However, including all one loop evolution and
defining the masses self-consistently, at their respective poles, moves the top
mass upward by some $10$ GeV to near $175$ GeV and the Higgs mass down by a
similar amount to near $125$ GeV.


title:
The Phenomenology of a Non-Standard Higgs Boson IN $W_{L}W_{L}$
  Scattering

abstract:
  In this paper we consider the phenomenology of a ``non-standard'' Higgs Boson
in longitudinal gauge-Boson scattering. First, we present a composite Higgs
model (based on an $SU(4)/Sp\,(4)$ chiral-symmetry breaking pattern) in which
there is a non-standard Higgs Boson. Then we explore, in a model-independent
way, the phenomenology of such a non-standard Higgs by calculating the chiral
logarithmic corrections to longitudinal gauge scattering. This calculation is
done using the Equivalence theorem and the Higgs is treated as a
scalar-isoscalar resonance coupled to the Goldstone Bosons of the
\mbox{$SU(2)_{L} \times SU(2)_{R}/SU(2)_{V}$} chiral symmetry breaking. We show
that the most important deviation from the one Higgs-doublet standard model is
parameterized by one unknown coefficient which is related to the Higgs width.
The implications for future hadron colliders are discussed.


title:
Leptoproduction of Heavy Quarks I-- General Formalism and Kinematics of
  Charged Current and Neutral Current Production Processes

abstract:
  Existing calculations of heavy quark production in charged-current and
neutral current lepton-hadron scattering are formulated differently because of
the artificial distinction of ``light'' and ``heavy'' quarks made in the
traditional approach. A proper QCD formalism valid for a wide kinematic range
from near threshold to energies much higher then the quark mass should treat
these processes in a uniform way. We formulate a unified approach to both types
of leptoproduction processes based on the conventional factorization theorem.
In this paper, we present the general framework with complete kinematics
appropriate for arbitrary masses, emphasizing the simplifications provided by
the helicity formalism. We illustrate this approach with an explicit
calculation of the leading order contribution to the quark structure functions
with general masses. This provides the basis for a complete QCD analysis of
charged current and neutral current leptoproduction of charm and bottom quarks
to be presented in subsequent papers.


title:
Leptoproduction of Heavy Quarks II -- A Unified QCD Formulation of
  Charged and Neutral Current Processes from Fixed-target to Collider Energies

abstract:
  A unified QCD formulation of leptoproduction of massive quarks in charged
current and neutral current processes is described. This involves adopting
consistent factorization and renormalization schemes which encompass both
vector-boson-gluon-fusion (flavor creation) and
vector-boson-massive-quark-scattering (flavor excitation) production
mechanisms. It provides a framework which is valid from the threshold for
producing the massive quark (where gluon-fusion is dominant) to the very high
energy regime when the typical energy scale \mu is much larger than the quark
mass m_Q (where the quark-scattering should be prevalent). This approach
effectively resums all large logarithms of the type (alpha_s(mu)
log(mu^2/m_Q^2)^n which limit the validity of existing fixed-order calculations
to the region mu ~ O(m_Q). We show that the (massive) quark-scattering
contribution (after subtraction of overlaps) is important in most parts of the
(x, Q) plane except near the threshold region. We demonstrate that the
factorization scale dependence of the structure functions calculated in this
approach is substantially less than those obtained in the fixed-order
calculations, as one would expect from a more consistent formulation.


title: New contribution to anomalous radiative $K^0$-decays

abstract:
  We present a new contribution to the $K_L\rightarrow \gamma \gamma$
amplitude, which is ${\cal{O}}(p^4)$ within the counting rules of chiral
perturbation theory. This direct (non-pole) amplitude, obtained from
short-distance $s \rightarrow d \gamma$ quark diagrams of order $e G_F
\alpha_s/\pi$, and similar $s \rightarrow d \gamma \gamma$ diagrams, can
account for about half of the experimental amplitude. Closely following the
description of the $\pi ^0\rightarrow \gamma \gamma$ and $K_L\rightarrow \gamma
\gamma$ processes in the variants of the same low-energy QCD, we find that both
of these processes are anomalous in the same sense. Then, by the
anomaly-matching principle, we arrive from the chiral-quark to the bosonic
counterparts for both of these processes. In this way we add the
$K_L\rightarrow \gamma \gamma$ decay to the existing list of anomalous
radiative prosesses.


title:
The Oblique Parameters In Electroweak Theory with Two Massless Higgs
  Doublets

abstract:
  The oblique parameters $S$ and $T$ are studied in electroweak theory with two
massless Higgs doublets. The effect of quadratic dependence on the charged
Higgs mass in the parameter $T$ could be cancelled. %when mass differences
between the charged and neutral scalars %become large. The constraint on the
charged Higgs mass from the parameter $T$ is not so stringent as it was
expected. The parameter $S$ can be both positive and negative but it can't take
large negative value. We search allowed scalar mass regions for both $S$ and
$T$ in the case of two different reference points.


title: Phase Structure of the Gauged Yukawa Model

abstract:
  Based on the ladder Schwinger-Dyson equation, we investigate phase struc-
ture of the gauged Yukawa model possessing a global $SU(2)_L \times SU(2)_R$
symmetry and an unbroken (vector-like) gauge symmetry. We show that even when
we tune the squared mass of the scalar boson in the Lagrangian to be positive,
there still exists the dynamical chiral symmetry breaking due to fermion pair
condensate (VEV of the composite scalar) triggered by the strong Yukawa
coupling larger than a certain critical value. We find a "nontrivial
ultraviolet fixed line" and "renormalized trajectories" in the
three-dimensional coupling space of the Yukawa coupling, the gauge cou- pling
and the "hopping parameter" of the elementary scalar field. Presence of the
gauge coupling is crucial to existence of the fixed line. Implications of the
result for the lattice calculation and the top quark condensate model are also
discussed.


title:
The $\alpha_s^3$ Corrections to the Effective Neutral Current and to the
  Z Decay Rate in the Heavy Top Quark Limit

abstract:
  We find the effective neutral current in the heavy top quark limit up to and
including the terms of order $\alpha_s^3$. The result is then employed to
compute the correction of the same order to the axial part of the Z decay rate
into hadrons ($\G^h_Z$) induced by the top-bottom quark mass splitting. The
calculations confirm the prediction made in a previous work of K.G.Ch. and
J.H.K\"uhn (Phys. Lett. B 308 (1993) 127), namely, the effect of the singlet
corrections of order $\alpha^3_s$ to the axial part of the $\G^h_Z$ should not
exceed 25\% - 30\% (depending on the values chosen for $\alpha_s(M_Z)$ and
$m_t$) of the magnitude of the leading (singlet) $\alpha_s^2$ term.


title: Top Production: Sensitivity to New Physics

abstract:
  The production cross--section and distributions of the top quark are
sensitive to new physics, e.g., the $t\overline{t}$ system can be a probe of
new resonances or gauge bosons that are strongly coupled to the top quark, in
analogy to Drell--Yan production. The existence of such new physics is expected
in dynamical electroweak symmetry breaking schemes, and associated with the
large mass of the top quark. The total top production cross--section can be
more than doubled, and distributions significantly distorted with a chosen
scale of new physics of $\sim 1 $ TeV in the vector color singlet or octet
$s$--channel. New resonance physics is most readily discernible in the
high--$p_T$ distributions of the single top quark and of the $W$ boson.


title:
Finite Mass Corrections to Leptonic Decay Constants in the Heavy Quark
  Effective Theory

abstract:
  We calculate finite mass corrections to leptonic decay constants in HQET
using QCD sum rules. The results are given to two--loop accuracy including
renormalization group analysis. The contribution of unknown two--loop anomalous
dimension matrix--elements is estimated. We find that the $1/m_Q$ corrections
to $f_P$, the decay constant of a pseudoscalar meson, amount $-(23\pm4\pm2)\%$
for the B meson. The first error comes from the sum rule uncertainty, the
second one from unknown or not accurately known matrix elements in HQET. We
obtain a ratio of vector to pseudoscalar decay constant of
$1.00\pm0.07+O(1/m_Q^2)$ for B mesons.


title: Can Stop be Light Enough for TRISTAN ?

abstract:
  \def\nle{{\stackrel{<}{\sim}}} We examine a possibility for existence of a
light supersymmetric partner of the top quark (stop) with mass 15 $\sim$ 16 GeV
in the framework of the minimal supergravity GUT model. Such light stop could
explain the slight excess of the high $p_{T}$ cross section of the
$D^{*\pm}$-meson production in two-photon process at TRISTAN. We point out that
the existence of such stop could change the dominant decay mode of gluino and
could weaken substantially present experimental bounds on the mass of gluino.
It seems that there is a finite parameter region allowing existence of such
light stop even if we consider the present experimental data. Inversely, if
such light stop was discovered at TRISTAN, masses and mixing parameters of the
other SUSY partners as well as masses of the Higgs and the top will be severely
constrained, for example, $m_{\tilde{g}}\simeq$85GeV,
$m_{\tilde{W_{1}}}\nle$50GeV, 110GeV$\nle m_{\tilde{\ell}}\nle$140GeV,
120GeV$\nle m_{\tilde{q}}\nle$160GeV, $\theta_{t}\simeq0.9$, $m_{h}\nle$ 65GeV
and 130GeV$\nle m_{t}\nle$140GeV. We also discuss briefly the proton decay and
the dark matter constraints.


title: Chiral Perturbation Theory

abstract:
  The basic ideas and some recent developments of the chiral perturbation
theory approach to hadron dynamics at low-energies are reviewed. (Invited talk
at the HADRON'93 Conference Como, Italy June 1993.)


title: SU(3) String-Flip Potential Models and Nuclear Matter

abstract:
  A Monte Carlo model for nuclear matter using a many body $SU_c(3)$ string
flip potential, with fixed colour, is investigated. The potential is
approximated by considering colour singlet flux tube formations that connect
only three quarks at a time. The model is compared with a similar string flip
model, proposed by Horowitz and Piekarewicz \cite{kn:HorowitzI}, that
approximates higher order flux tube formations by connecting quarks in colour
singlet chains. The former model gives an EMC nucleon ``swelling'' effect,
whereas the latter gives an opposite effect. Possible discrepancies between the
two models are discussed.


title:
Diagnostic Power of Future Colliders for Z'Couplings to Quarks and
  Leptons: e+e- versus pp Colliders

abstract:
  We study the diagnostic power of future $e^+e^-$ colliders with ${\sqrt {s}}
= 500$ GeV (the New Large Collider ($NLC$)) for a model independent
determination of the $Z'$ gauge couplings to quarks and leptons. The
interference of the $Z'$ propagator with the photon and the $Z$ propagator in
the two-fermion final state probes are sensitive to the magnitude as well as
relative signs of quark and lepton charges. For $Z'$ with $M_{Z'} \sim 1 $ TeV
{\it all } the quark and lepton charges can be determined to around $10-20 \%$,
provided heavy flavor tagging and longitudinal polarization of the electron
beam is available. The errors are $2-10$ times larger without polarization, and
very little information can be obtained about quark charges without heavy
flavor tagging. We point out the complementarity of future hadron colliders. At
the CERN Large Hadron Collider ($LHC$) primarily the magnitude of three out of
four corresponding couplings can be measured; however, their error-bars are
typically by a factor of $\sim 2$ smaller than those at the $NLC$.


title: Quark-Gluon Plasma Freeze-out from a Supercooled State?

abstract:
  We consider time-scales of first-order deconfinement or chiral-symmetry
restoring phase transition in high energy heavy ion collisions at RHIC and LHC
energies. Recently it was shown that the system must supercool below $T_c$
before the nucleation of hadronic bubbles is sufficiently rapid to overcome the
expansion rate. It is shown here that the expected time-scales of high energy
heavy ion reactions are sufficiently short to prevent the reheating of the
system to near $T_c$. If quark-gluon plasma is produced in these collisions, it
may have to hadronize from a supercooled state and the hadrons produced during
rehadronization may freeze-out almost immediately.


title: Neutrino Lasing in the Sun

abstract:
  Applying the phenomenon of neutrino lasing in the solar interior, we show how
the rate for the generic neutrino decay process `\nu -> fermion + boson', can
in principal be enhanced by many orders of magnitude over its normal decay
rate. Such a large enhancement could be of import to neutrino-decay models
invoked in response to the apparent deficit of electron neutrinos observed from
the sun. The significance of this result to such models depends on the specific
form of the neutrino decay, and the particle model within which it is embedded.


title: Comparison of Diagnostic Z' Physics at Future pp and e+e- Colliders

abstract:
  We present recent developments in the diagnostic study of heavy gauge bosons
at future $pp$ (CERN LHC) and $e^+e^-$ (NLC) colliders with the emphasis on the
model independent determination of gauge couplings of $Z'$ to quarks and
leptons. The analysis reflects a complementary diagnostic power of the LHC and
the NLC (c.m. energy 500 GeV, integrated luminosity 20 fb$^{-1} $). At the NLC
for $M_{Z'} \sim 1 $ TeV {\it all } the quark and lepton charges can be
determined to around $10-20 \%$, provided heavy flavor tagging and longitudinal
polarization of the electron beam is available. At the LHC primarily the
magnitude of three (out of four) normalized couplings can be determined,
however typical uncertainties are by a factor $\sim 2$ smaller than at the NLC.


title:
One-Loop N Gluon Amplitudes with Maximal Helicity Violation via
  Collinear Limits

abstract:
  We present a conjecture for the $n$-gluon one-loop amplitudes with maximal
helicity violation. The conjecture emerges from the powerful requirement that
the amplitudes have the correct behavior in the collinear limits of external
momenta. One implication is that the corresponding amplitudes where three or
more gluon legs are replaced by photons vanish for $n>4$.


title: Quadratic Divergences in GUTs with Vanishing One-Loop Beta Functions

abstract:
  All members of a recently proposed new set of (non-supersymmetric) grand
unified theories with at the one-loop level vanishing beta functions for the
gauge, Yukawa, and scalar-boson self-interaction coupling constants are shown
to involve, already at the one-loop level, quadratically divergent
contributions to both the vector-boson and scalar-boson masses.


title: Complete Classes of GUTs with Vanishing One-Loop Beta Functions

abstract:
  By explicit solution of the one-loop finiteness conditions for all
dimensionless coupling constants (i.~e., gauge coupling constant as well as
Yukawa and quartic scalar-boson self-interaction coupling constants), two
classes of grand unified theories characterized by renormalization-group beta
functions which all vanish at least at the one-loop level are constructed and
analyzed with respect to the (suspected) appearance of quadratic divergences,
with the result that without exception in all of these models the masses of
both vector and scalar bosons receive quadratically divergent one-loop
contributions.


title: Anomalous Neutrino Reactions at HERA

abstract:
  We study the sensitivity of HERA to new physics using the helicity suppressed
reaction $e_R p \rightarrow \nu X $, where the final neutrino can be a standard
model one or a heavy neutrino. The approach is model independent and is based
on an effective lagrangian parametrization. It is shown that HERA will put
significant bounds on the scale of new physics, though, in general, these are
more modest than previously thought. If deviations from the standard model are
observed in the above processes, future colliders such as the SSC and LHC will
be able to directly probe the physics responsible for these discrepancies}


title:
Corrections to Hyperfine Splitting and Lamb Shift Induced by the
  Overlapping Two-Loop Electron Self-Energy Insertion in the Electron Line

abstract:
  Contributions to HFS and to the Lamb shift intervals of order
$\alpha^2(Z\alpha)^5$ induced by the graph with the two-loop overlapping
electron self-energy diagram inserted in the electron line are considered.
Explicit expression for the overlapping two-loop self-energy diagram in the
Fried-Yennie gauge is obtained. Contributions both to HFS and Lamb shift
induced by the diagram containing such subgraph are calculated.


title: In Pursuit of Gamma

abstract:
  After reviewing techniques for extracting clean information on CP-violating
phase angles from $B$ decays, we explain the rules for finding decay modes that
can probe the phase angle $\gamma$ of the unitarity triangle. We identify the
more promising of these ``$\gamma$ modes,'' estimate their branching ratios,
and examine the degree to which they are theoretically clean. We then show that
when the quark mixing matrix is not approximated as usual, but is treated
exactly, none of the ``$\gamma$ modes'' actually measures $\gamma$. Rather,
each of them measures $\gamma$ plus some correction. In all modes, the
correction is small enough to be disregarded in first-generation experiments,
but in some of them, it may be large enough to be observed in second-generation
experiments. Our treatment of the $\gamma$ modes calls attention to the fact
that when the quark mixing matrix is treated exactly, there are six unitarity
triangles, rather than just one triangle. However, only four of the angles in
these six triangles are independent. Examining the role played by these four
angles, we discover that, in principle at least, measurements of nothing but
CP-violating asymmetries in $B$ decays are sufficient to determine the entire
quark mixing matrix.


title: Topological Classification of Odd-Parity Sphaleron Deformations

abstract:
  We discuss topological aspects of the electroweak sphaleron and its
odd-parity deformations. We demonstrate that they are uniquely classified in
terms of their odd and even-parity pure gauge field behaviour at spatial
infinity. Fermion level crossing occurs only for odd-parity configurations
which are topologically disconnected from the vacuum. They contribute to the
high temperature unsuppressed baryon violating thermal transitions.
Deformations with even-parity pure gauge behaviour at spatial infinity are
topologically trivial and do not mediate baryon number violation in the early
Universe.


title: On sphaleron deformations induced by Yukawa interactions

abstract:
  Due to the presence of the chiral anomaly sphalerons with Chern-Simons number
a half (CS=1/2) are the only static configurations that allow for a fermion
level crossing in the two-dimensional Abelian-Higgs model with massless
fermions, i.e. in the absence of Yukawa interactions. In the presence of
fermion-Higgs interactions we demonstrate the existence of zero energy
solutions to the one-dimensional Dirac equation at deformed sphalerons with
CS$\neq 1/2 .$ Induced level crossing due to Yukawa interactions illustrates a
non-trivial generalization of the Atiyah-Patodi-Singer index theorem and of the
equivalence between parity anomaly in odd and the chiral anomaly in even
dimensions. We discuss a subtle manifestation of this effect in the standard
electroweak theory at finite temperatures.


title: Bounds on Vector Leptoquarks

abstract:
  We derive bounds on vector leptoquarks coupling to the first generation,
using data from low energy experiments as well as from high energy
accelerators. Similarly to the case of scalar leptoquarks, we find that the
strongest indirect bounds arise from atomic parity violation and universality
in leptonic pi decays. These bounds are considerably stronger than the first
direct bounds of HERA, restricting vector leptoquarks that couple with
electromagnetic strength to right-handed quarks to lie above 430 GeV or 460
GeV, and leptoquarks that couple with electromagnetic strength to left-handed
quarks to lie above 1.3 TeV, 1.2 TeV and 1.5 TeV for the SU(2)_W singlet,
doublet and triplet respectively.


title: Radiative Corrections in the Presence of Majorana Neutrinos

abstract:
  We have studied the radiative corrections from the fourth generation leptons
in the context of the see-saw mechanism. We have estimated numerically the
differential cross section for the process (${\rm e}^{+}{\rm e}^{-}\!
\rightarrow {\rm W}^{+}{\rm W}^{-}$) at one-loop level, and found in the cross
section the threshold behaviors for Majorana neutrino productions.


title: External Gauge Invariance and Anomaly in BS Vertices and Boundstates

abstract:
  A systematic method is given for obtaining consistent approximations to the
Schwinger-Dyson(SD) and Bethe-Salpeter(BS) equations which maintain the
external gauge invariance. We show that for any order of approximation to the
SD equation there is a corresponding approximation to the BS equations such
that the solutions to those equations satisfy the Ward-Takahashi identities of
the external gauge symmetry. This formulation also clarifies the way how we can
calculate the Green functions of current operators in a consistent manner with
the gauge invariance and the axial anomaly. We show which type of diagrams for
the $\pi^0\rightarrow\gamma\gamma$ amplitude using the pion BS amplitude give
result consistent with the low-energy theorem. An interesting phenomenon is
observed in the ladder approximation that the low energy theorem is saturated
by the zeroth order terms in the external momenta of the pseudoscalar BS
amplitude and the vector vertex functions.


title: Instantons And Baryon Mass Splittings in the MIT Bag Model

abstract:
  The contribution of instanton-induced effective inter-quark interactions to
the baryon mass splittings was considered in the bag model. It is found that
results are different from those obtained in the constituent quark model where
the instanton effects are like those from one-gluon exchange. This is because
in the context of the bag model calculation the one-body instanton-induced
interaction has to be included.


title: Electroweak Sphaleron in Large Higgs Boson Mass Limit

abstract:
  Since the TRIVIALITY argument of the Higgs sector requires the existence of
new physics beyond the standard model, there should exist a cutoff $\Lambda$
beyond which the standard model will breakdown. The cutoff can be determined
from the position of the Landau pole. We study the effects of this cutoff on
the energy of the electroweak sphaleron, $E^{spha}$, in the large Higgs boson
mass limit. We found that $E^{spha}$ becomes arbitrarily large as the Higgs
boson mass increases. This is in contrast to the well-known result, which is
held in the standard model and a wide class of its extensions, that $E^{spha}$
is stable against the variation of the {\it bare} Higgs boson mass. The
physical meaning of this result is discussed.


title: Multiplicity with a Thrust Cut

abstract:
  We evaluate the multiplicity of hadrons in the $e^+e^-$-annihilation at a
given thrust $T$ in the modified leading-log approximation, including
$O(\sqrt{\alpha_s})$ corrections. The calculation is done at a large value of
$\tau =1-T$ by the use of the factorisation which takes place in the
one-particle-inclusive cross section at a given $\tau$. At a small $\tau$, a
different type of factorisation takes place, which also enable us to evaluate
the multiplicity. Two approaches are compared numerically. Measuring this
quantity near $\tau =1/3$, we can determine the multiplicity ratio between a
gluon-jet and a quark-jet.


title: Signatures of an invisibly decaying Higgs particles at LHC

abstract:
  The Higgs particle can decay dominantly into an invisible channel in the
Majoron models. We have explored the prospect of detecting such a Higgs
particle at LHC via its associated production with a gluon, Z or W boson. While
the signal/background ratio is too small for the first process, the latter two
provide viable signatures for detecting such a Higgs particle.


title:
The Origin and Mechanisms of CP Violation In the Two-Higgs Doublet Model
  and Masses of the Exotic Scalars

abstract:
  I rebuild a conventional two-Higgs doublet model by relaxing the spontaneous
CP violation and considering approximate global U(1) family symmetries. So that
the domain-wall problem does not explicitly arise at the weak scale, but CP
violation still solely originates from a single CP-phase in the vacuum after
spontaneous symmetry breaking. With this phase four types of CP-violating
mechanism are induced in the model. In particular, by a new type of the
mechanism, both the indirect- and direct- CP violation (i.e. $\epsilon$ and
$\epsilon'/\epsilon$) in kaon decay and the neutron electric dipole moment can
be consistently accommodated. The masses of the exotic scalars are weakly
constrained in the model and searching for these particles is worthwhile in the
presently accessible energy range. Substantial CP violation may occur in the
heavy quark and lepton sectors and probing their effects provides a challenge
at B-factory and colliders.


title: Larger Domains of Disoriented Chiral Condensate Through Annealing

abstract:
  Relativistic heavy ion collisions can generate metastable domains in which
the chiral condensate is disoriented. Nucleus-sized domains can yield
measurable fluctuations in the number of neutral and charged pions. We propose
a scenario in which domains are `annealed' by a dynamically evolving effective
potential in the heavy ion system. Domains of sizes exceeding 3~fm are possible
in this scenario.


title:
Color Confinement, Quark Pair Creation and Dynamical Chiral-Symmetry
  Breaking in the Dual Ginzburg-Landau Theory

abstract:
  We study the color confinement, the $q$-$\bar q$ pair creation and the
dynamical chiral-symmetry breaking of nonperturbative QCD by using the dual
Ginzburg-Landau theory, where QCD-monopole condensation plays an essential role
on the nonperturbative dynamics in the infrared region. As a result of the dual
Meissner effect, the linear static quark potential, which characterizes the
quark confinement, is obtained in the long distance within the quenched
approximation. We obtain a simple expression for the string tension similar to
the energy per unit length of a vortex in the superconductivity physics. The
dynamical effect of light quarks on the quark confining potential is
investigated in terms of the infrared screening effect due to the $q$-$\bar q$
pair creation or the cut of the hadronic string. The screening length of the
potential is estimated by using the Schwinger formula for the $q$-$\bar q$ pair
creation. We introduce the corresponding infrared cutoff to the strong
long-range correlation factor in the gluon propagator as a dynamical effect of
light quarks, and obtain a compact formula of the quark potential including the
screening effect in the infrared region. We investigate the dynamical
chiral-symmetry breaking by using the Schwinger-Dyson equation, where the gluon
propagator includes the nonperturbative effect related to


title:
Electromagnetic nucleon properties and quark sea polarization in the
  Nambu-Jona-Lasinio model

abstract:
  In this paper we present the derivation as well as the numerical results for
all electromagnetic form factors of the nucleon within the semibosonized
Nambu--Jona-Lasinio (chiral quark soliton) model. Other observables, namely the
nucleon mean squared radii, the magnetic moments and the nucleon--$\Delta$
splitting are also computed. The calculation has been done taking into account
the quark sea polarization effects. The final results, including rotational
$1/N_c$ corrections, are compared with the existent experimental data and they
are found to be in a good agreement for the constituent quark mass of
$400$--$420\ MeV$.


title: Standard Model Expectations for CP Violation

abstract:
  I review the predictions and expectations of the CKM model for CP violation
in both the $K^0-\bar K^0$ and $B^0-\bar B^0$ systems. A brief discussion of CP
violation in charged $K$- and $B$-decays is also included, as well as some
remarks on the electric dipole moments of the neutron and the electron.


title:
Exact Heavy to Light Meson Form Factors in the Combined Heavy Quark,
  Large $N_c$ and Chiral Limits

abstract:
  We demonstrate that the form factors of local operators between a heavy meson
state (like the~$B$) and a light pseudoscalar state (like the pion) are given
exactly by a single pole form in the combined heavy quark, large $N_c$ (number
of colors) and chiral limits. We discuss the deviations from this exact result
from finite heavy quark masses, non-zero light quark masses and finite $N_c$.
We comment on some implications of this result.


title: QCD, the Parton Model, and the Nucleon Polarised Structure Functions}

abstract:
  The present talk summarises the 1993 situation in understanding the spin
structure of the nucleon via electron and muon polarised deep--inelastic
scattering (PDIS). The central question I shall address here is if the data can
be interpreted as evidence for polarisation in the ``strange'' nucleon ``sea'',
and I conclude that they can not: incidentally, I also find that they can not
be constructed as evidence for violation of perturbative QCD (PQCD), either.
  Talk presented at ``Quinto Convegno su Problemi di Fisica Nucleare Teorica'',
Cortona (Arezzo, Italy), October 1993.
  To be published in the proceedings: ``Perspectives on Theoretical Nuclear
Physics (V)'', L. Bracci, et al., eds. (ETS Ed., Pisa 1994)


title: A Hierarchy of Effective Field Theories of Hot Electroweak Matter

abstract:
  Abst\-ract: A hierarchy of effective three-dimensional theories of finite
temperature electroweak matter is studied. First an integration over non-static
modes leads to an effective theory containing a gauge field $A_{i}^{a}$, an
adjoint Higgs field $A_{0}^a$ and the fundamental Higgs field $\phi_{\alpha}$.
We carry out the integration in the 1-loop approximation, study renormalisation
effects and estimate quantitatively those terms of the effective action which
are suppressed by inverse powers of the temperature. Secondly, because of the
existence of well-separated thermal mass scales, $A_{0}^a$ can be integrated
over, and finally also $\phi_{\alpha}$, leaving an effective theory of the
$A_{i}^{a}$.In the analysis of the subsequent models particular attention is
paid to the screening of the magnetic fluctuations due to the integrated-out
degrees of freedom. Files of 2 Tables and 4 Figures are available in
(la)tex-format upon request


title: Finite $3\pi$ Cut Approximation for the $\pi N\bar{N}$ Form Factor

abstract:
  Assuming the length of the $3\pi$ cut to be finite and approximating the
integrated amplitude by a constant, we derive an expression for the $\pi
N\bar{N}$ form factor which is very close to that given by a simple pole. The
specific predictions of the obtained form factor for the region of small
momentum transfer are discussed along the lines of the Goldberger-Treiman
relation.


title:
Heavy Higgs Boson Production in Association with Three Jets at Hadron
  Supercolliders

abstract:
  We consider the real emission QCD correction to heavy Higgs boson production
via weak boson fusion in high energy $pp$ collisions. The ${\cal O}(\alpha_s)$
corrections are determined for the complete electroweak $q q \rightarrow q q
W^+ W^-$ process. The presence of a third parton in the final state affects the
formation of rapidity gaps only slightly. In particular, soft emission into the
gap region is severely suppressed. Also, we investigate how the additional hard
emission affects forward-jet-tagging and central-jet-vetoing efficiencies in
the search for $H \rightarrow W^+ W^- \rightarrow \ell^+ \nu \ell^- \bar{\nu}$
decays.


title: E+ E- -> Tau+ Tau- at the Threshold and Beyond

abstract:
  The excitation curve for the $\tau^+ \, \tau^-$ production in electron
positron annihilation near the threshold is revisited with the aim of updating
and extending a previous work. We find that the corrections of the relative
magnitude $O(\alpha)$ near the threshold are significantly contributed by the
radiative modification of the Coulomb interaction between the $\tau$ leptons.
The interpolation between the Coulomb effects at the threshold and the
relativistic effects at higher energies is considered and the resulting formula
is argued to have relative accuracy up to, but not including, terms of the
order of $\alpha^2$ at any velocity of the $\tau$ leptons.


title:
On the Motion of Heavy Quarks inside Hadrons: Universal Distributions
  and Inclusive Decays

abstract:
  In previous papers we have pointed out that there exists a QCD analog of the
phenomenological concept of the so called Fermi motion for the heavy quark
inside a hadron. Here we show in a more detailed way how this comes about and
we analyze the limitations of this concept. Non-perturbative as well as
perturbative aspects are included. We emphasize both the similarities and the
differences to the well-known treatment of deep inelastic lepton-nucleon
scattering. We derive a model-independent {\em lower} bound on the kinetic
energy of the heavy quark inside the hadron.


title: Is the Top Quark Really Heavier than the $W$ Boson?

abstract:
  Scalar induced top decays may drastically suppress $B(t\to \ell\nu + jet)$
and still hide the top below $M_W$. The $p\bar p$ collider experiments should
enlarge the scope and study the $m_t - B(t\to\ell\nu j)$ plane. Specific model
signatures such as $t\to ch^0\to cb\bar b$ (multiple high $p_T$ $b$-jets) and
$t\to bH^+\to bc\bar s$, $b\tau^+\nu$ (with $B(t\to b\tau\nu) \
\raisebox{-.5ex}{\rlap{$\sim$}} \raisebox{.4ex}{$<$}\ 1/3$) should be explored.
Without ruling out these possibilities, isolated lepton signals in the future
might actually be due to the 4th generation $t^\prime$ or $b^\prime$ quark,
while top quark and toponium physics could still turn up at LEP-II.


title:
Radiative Corrections to $\zbb$ from Colored Scalars in a Model with
  Dynamical Symmetry Breaking

abstract:
  Isodoublet color-octet scalar bosons appear in the low-energy limit of a
natural extension of the Standard Model in which the electroweak symmetry is
broken by a $t\bar t$ condensate. We briefly discuss the model and show that
radiative corrections (involving these scalars) to the branching ratio
$R_b=\Gamma (Z\rightarrow b\bar b)/\Gamma (Z\rightarrow {\rm hadrons})$ are
negative and thus place a stringent lower bound on the masses of the colored
scalars. This turns out to be $\sim 400$ GeV with $m_t=150$ GeV and increases
quadratically with $m_t$. It is emphasized that $R_b$ is a parameter that is
well-determined experimentally and that theoretical estimates are relatively
free from uncertainties emanating from hadronic corrections and are
comparatively insensitive to the value of the top mass.


title: Finite Temperature Correlators in the Schwinger Model

abstract:
  We discuss the correlation function of hadronic currents in the Schwinger
model at finite temperature $T$. We explicitly construct the retarded
correlator in real time and obtain analytical results for the Euclidean
correlator on a torus. Both constructions lead to the same finite temperature
spectral function. The spatial screening lengths in the mesonic channels are
related to the dynamical meson mass $m=e/\sqrt{\pi}$ and not $2\pi T$ even in
the infinite temperature limit. The relevance of our results for the finite
temperature problem in four dimensions is discussed.


title: Testing Gluon Self-Interactions in Three Jet Events at Hadron Colliders

abstract:
  The effective operator tr(G^3) is the only dimension-6 gluonic operator that
cannot be related to four-quark operators. A peculiar property of this operator
is that it does not contribute to two-jet production at hadron colliders, at
the level of one operator insertion and leading-order in alpha_s; therefore we
study its effects on three jet events. To calculate the helicity amplitudes
induced by this operator we make extensive use of collinear factorization. We
propose several ways of detecting the tr(G^3) signal, one of which exploits its
non-trivial behavior under azimuthal rotations of two almost collinear jets.


title:
Nonstandard Quartic Self Interactions of Electroweak Vector Bosons
  within a Gauge Invariant Higher-Derivative Term

abstract:
  A locally SU(2)xU(1)-invariant term of dimension six with effective
interactions of the electroweak gauge and Higgs fields is examined. This term
also contains higher derivatives of the fields. It yields nonstandard quartic
gauge-boson self-interactions but neither nonstandard cubic self-interactions
nor tree-level effects on presently measurable quantities.


title:
On the Equivalence Theorem in the $\chi PT$ Description of the Symmetry
  Breaking Sector of the Standard Model

abstract:
  We develop an alternative formulation of the symmetry breaking sector of the
Standard Model as a gauged non-linear sigma model (NLSM) following the
philosophy of the Chiral lagrangian approach, which is the only compatible with
all the experimental and theoretical constraints. We derive the BRS symmetry of
the model and the corresponding quantum lagrangian, which is a generalization
of the standard Faddeev-Popov method, in a way which is covariant with respect
to the reparametrizations of the coset space of the NLSM. Then we use the BRS
invariance of the quantum lagrangian to state the Equivalence Theorem for the
renormalized $S$-matrix elements calculated as a chiral expansion.


title:
Description of Relativistic Heavy--Light Quark--Antiquark Systems via
  Dirac Equations

abstract:
  Starting from the QCD Lagrangian and taking into account both perturbative
and nonperturbative effects, we use the method of vacuum correlators to derive
the Dirac equation (rigorously for the Coulomb interaction and heuristically
for the confining potential) for a system consisting of a light quark and heavy
antiquark. As a result the confining potential is a Lorentz scalar, and the
Coulomb part the fourth component of a 4-vector. The energy spectrum of the
Dirac equation is considered for these potentials. Numerical calculations of
energy eigenvalues $E=E_{n\kappa}$ are performed, and some exact solutions of
the Dirac equation in the case $E=0$ are found. An effective-potential method
convenient for qualitative study of the solutions of the Dirac equation is
developed. The connection with experimental spectra of $D$- and $B$-mesons is
briefly discussed.


title: Long Distance Contribution to $K^+ \rightarrow \pi^+ \nu \bar\nu$

abstract:
  We estimate the long distance contribution to the $K^+ \rightarrow \pi^+ \nu
\bar\nu$ decay amplitude using chiral perturbation theory. We find that it is
likely to be less than a few percent of the part of the short distance
contribution proportional to the square of the charm quark mass. In the large
$N_c$ limit the leading (in chiral perturbation theory) long distance
contribution to $K^+ \rightarrow \pi^+ \nu \bar\nu$ from Feynman diagrams with
a $W$ and $Z^0$ vanishes.


title:
Finite-element quantum electrodynamics. II. Lattice propagators, current
  commutators, and axial-vector anomalies

abstract:
  We apply the finite-element lattice equations of motion for quantum
electrodynamics given in the first paper in this series to examine anomalies in
the current operators. By taking explicit lattice divergences of the vector and
axial-vector currents we compute the vector and axial-vector anomalies in two
and four dimensions. We examine anomalous commutators of the currents to
compute divergent and finite Schwinger terms. And, using free lattice
propagators, we compute the vacuum polarization in two dimensions and hence the
anomaly in the Schwinger model. A discussion of our choice of gauge-invariant
current is provided.


title: Low-Energy Photon-Photon Collisions to Two-Loop Order

abstract:
  We evaluate the amplitude for $\gamma \gamma \rightarrow \pi^0 \pi^0$ to two
loops in chiral perturbation theory. The three new counterterms which enter at
this order in the low-energy expansion are estimated with resonance saturation.
We find that the cross section agrees rather well with the available data and
with dispersion theoretic calculations even substantially above threshold.
Numerical results for the Compton cross section and for the neutral pion
polarizabilities are also given to two-loop accuracy.


title: Hyperons in the bound state approach with vector mesons

abstract:
  We investigate a model for hyperons based on the bound state approach in
which vector mesons are explicitly incorporated. We show that for empirical
values of the mesonic parameters the strange hyperon spectrum is well
reproduced. We also discuss the extension of the model to heavier flavors. We
show that the explicit presence of the heavy vectors leads to good predictions
for the heavy baryon masses.


title: Protecting the Primordial Baryon Asymmetry From Erasure by Sphalerons

abstract:
  If the baryon asymmetry of the universe was created at the GUT scale,
sphalerons together with exotic sources of $(B-L)$-violation could have erased
it, unless the latter satisfy stringent bounds. We elaborate on how the small
Yukawa coupling of the electron drastically weakens previous estimates of these
bounds.


title: Heavy Quark Solitons: Strangeness and Symmetry Breaking

abstract:
  We discuss the generalization of the Callan-Klebanov model to the case of
heavy quark baryons. The light flavor group is considered to be $SU(3)$ and the
limit of heavy spin symmetry is taken. The presence of the Wess-Zumino-Witten
term permits the neat development of a picture , at the collective level, of a
light diquark bound to a ``heavy" quark with decoupled spin degree of freedom.
The consequences of $SU(3)$ symmetry breaking are discussed in detail. We point
out that the $SU(3)$ mass splittings of the heavy baryons essentially measure
the ``low energy" physics once more and that the comparison with experiment is
satisfactory.


title: Non-Abelian Excitations of the Quark-Gluon Plasma

abstract:
  We present new, non-abelian, solutions to the equations of motion which
describe the collective excitations of a quark-gluon plasma at high
temperature. These solutions correspond to spatially uniform color
oscillations.


title: Energy-Momentum Tensors for the Quark-Gluon Plasma

abstract:
  We construct the energy-momentum tensor for the gauge fields which describe
the collective excitations of the quark-gluon plasma. We rely on the
description of the collective modes that we have derived in previous works. By
using the conservation laws for energy and momentum, we obtain three different
versions for the tensor $T^{\mu\nu}$, which are physically equivalent. We show
that the total energy constructed from $T^{00}$ is positive for any non-trivial
field configuration. Finally, we present a new non-abelian solution of the
equations of motion for the gauge fields. This solution corresponds to
spatially uniform color oscillations of the plasma.


title:
$\rho$ Parameter in the Vector Condensate Model of Electroweak
  Interactions

abstract:
  In the standard model of electroweak interactions the Higgs doublet is
replaced by a doublet of vector bosons and the gauge symmetry is broken
dynamically. This generates masses for the gauge bosons and fermions, as well
as it fixes the interactions in the model. The model has a low momentum scale.
In this note we show that the model survives the test of the $ \rho $
parameter, and to each momentum scale $ \rho $ chooses a possible range of
vector boson masses.


title: A New Method to Predict Meson Masses

abstract:
  The Feynman--Hellmann theorem is used to show that vector meson energy
eigenvalues are monotonically decreasing functions of the reduced masses of
their constituent quarks. The experimental meson masses are used to put
constraints on the values of quark masses and to predict the masses of some as
yet undiscovered mesons. The mass of the $B_c^*$ meson is predicted to be
$6320\pm 10$ MeV, and, with less precision, the masses of a number of excited
vector mesons are also predicted.


title:
Anomalous Dimension of Non-Singlet Wilson Operators at O(1/N_f) in Deep
  Inelastic Scattering

abstract:
  We use the large N_f self consistency formalism to compute the $O(1/N_f)$
critical exponent corresponding to the renormalization of the flavour
non-singlet twist two Wilson operators which arise in the operator product
expansion of currents in deep inelastic processes. Expanding the
$d$-dimensional expression in powers of $\epsilon$ $=$ $(4-d)/2$ the
coefficients of $\epsilon$ agree with the known two loop structure of the
corresponding renormalization group function and we deduce analytic expressions
for all moments, $n$, at three and higher orders in perturbation theory in the
$\overline{\mbox{MS}}$ scheme at $O(1/N_f)$.


title: Decisive Search for a Diquark-Antidiquark Meson with Hidden Strangeness

abstract:
  Diquark-antidiquark states are expected to exist as a natural complement of
mesons and baryons. Although they were predicted long ago, and some candidates
were found experimentally, none has, as yet, been reliably identified. We
suggest that the search for the so-called $C(1480)$-meson in reactions such as
photoproduction $\gamma N\rightarrow\phi\pi N$ and $K N \rightarrow \phi \pi
\Lambda$ should provide a decisive way to settle this issue. Estimates of the
cross sections are given using present experimental information on the C-meson
and assuming its diquark-antidiquark structure. Sizable cross sections are
predicted (of the order of 0.1 $\mu$b for photoproduction and of the order of
0.1 mb for $KN$ at the maximum with an insignificant background). Failure to
find this kind of signal would imply that the C-meson is {\it not} a
diquark-antidiquark state.


title: Baryons in Effective Chiral Quark Models with Polarized Dirac Sea

abstract:
  We give a comprehensive review of concepts and numerical calculations for
SU(2) and SU(3) baryonic systems which are considered as many body systems
composed of three quarks coupled to a polarized Dirac sea by a
Nambu--Jona-Lasinio like interaction. The general formalism as well as the
construction and numerical solution of non-topological mean field solitons are
exhibited. Systems with good spin/flavour/isospin/momentum quantum numbers are
obtained by using the SU(2)/SU(3)-cranking and the pushing approach. The
article contains also recent results for various extensions of the model, e.g.
vector and axialvector couplings or the inclusion of scale invariance.
Furthermore the relationship of this approach to topological models (Skyrme
type) as well as to (valence-)quark-meson models (Gell-Mann--Levi chiral sigma
model) is explained. (to be publ. in Rep.Prog.Phys.)


title: Photoproduction of Very Light Gluinos

abstract:
  Current experiments allow the possibility of gluino masses below about 600
MeV if the lifetime of the gluino is longer than 100 picoseconds. If the mass
and lifetime are in this window, then photoproduction of pairs of gluino-gluon
bound states can provide a means to observe them. The cross section is large
enough that the window can be fully explored, up to lifetimes exceeding a
microsecond, at high luminosity electron accelerators.


title: The Dilated Chiral Quark Model

abstract:
  It is argued that constituent quarks live in an effective theory that
possesses an approximate conformal invariance. An effective lagrangian is
constructed which in the large-$\nc$ approximation incorporates Regge
asymptotic constraints. The resulting picture explains why linear-sigma models
provide successful constituent quark descriptions, both at zero and finite
temperature. Our analysis suggests an interesting relation between non-linearly
realized conformal invariance and the completion of chiral multiplets in the
broken symmetry phase.


title:
Two-Loop Radiative Corrections to the Lightest Higgs Boson Mass in the
  Minimal Supersymmetric Model

abstract:
  In the minimal supersymmetric model (MSSM), the upper limit of the lightest
Higgs boson mass, $\mhl$, depends strongly on the top quark mass, $m_t$. We
have computed the dominant two-loop radiative corrections to this upper limit
of $\mhl$ in order to eliminate large uncertainties due to QCD and $m_t^6$
corrections. It is shown that the QCD corrections significantly reduce the
one-loop corrections. As a result, the SUSY parameter space accessible to LEP
experiments is significantly increased.


title: Electroweak String Configurations with Baryon Number

abstract:
  In the context of electroweak strings, the baryon number anomaly equation may
be reinterpreted as a conservation law for baryon number minus helicity. Since
the helicity is a sum of the link and twist numbers, linked or twisted loops of
electroweak string carry baryon number. We evaluate the change in the baryon
number obtained by delinking loops of electroweak $Z-$string and show that
twisted electroweak string segments may be regarded as extended sphalerons. We
also suggest an alternative scenario for electroweak baryogenesis.


title:
The Higher Derivative Expansion of the Effective Action by the
  String-Inspired Method, Part I

abstract:
  The higher derivative expansion of the one-loop effective action for an
external scalar potential is calculated to order O(T**7), using the
string-inspired Bern-Kosower method in the first quantized path integral
formulation. Comparisons are made with standard heat kernel calculations and
with the corresponding Feynman diagrammatic calculation in order to show the
efficiency of the present method.


title: Intermittency in soft hadronic processes and Zip-model

abstract:
  A low constituent number scheme based on the nontrivial gluon string
splitting (the Zip--model) is shown to yield a substantial intermittency for
soft hadronic processes. With a simplest addition of the Bose--Einstein
correlations the remarkable agreement with the NA22 experimental data on
rapidity factorial moments is reached.


title: The Vacuum Theta-Angle is Zero in Non-Abelian Gauge Theories

abstract:
  We argue that gauge transformations with arbitrary fractional winding numbers
should be allowed in a non-Abelian gauge theory. This eliminates the
topological distinction between large and small gauge transformations. We prove
that the states which satisfy the Gauss's law constraint are strictly invariant
under gauge transformations, i.e. no phase shift occurs. In other words, the
vacuum theta-angle is zero. Our observation does not resolve the strong CP
problem.


title:
Aspects of $\chi$ and $\psi$ Production in Polarized Proton-Proton
  Collisions

abstract:
  Several topics of relevance to low transverse momentum $\psi$ and
$\chi_{1,2}(c\overline{c})$ production in polarized proton-proton collisions
are discussed. The leading ${\cal O}(\alpha_S^3)$ contributions to the low
$p_T$ $\chi_1$ production cross-sections via $gg$, $qg$, and $q\overline{q}$
initial states are calculated as well as the corresponding spin-spin
asymmetries. We find that $\chi_1$ production increases relative to direct
$\psi$ and $\chi_2$ production, providing up to $25\%$ of the observable
$e^+e^-$ pairs arising from $\psi$ decays in $pp$ collisions at $\sqrt{s} =
500\,GeV$. The spin-dependence of $\chi_1$ production, however, is much smaller
than for either direct $\psi$ or $\chi_2$ production and so will likely be far
less useful than either process in probing the polarized gluon structure
function of the proton. A subset of the ${\cal O}(\alpha_S^3)$ radiative
corrections to $\chi_2$ production involving initial state quarks are also
performed and compared to leading order $gg \rightarrow \chi_2$ predictions.


title:
The Instantaneous Approximation to the Transition Matrix Elements
  between Two Bound States

abstract:
  Under the framework of the Bethe-Salpeter (B.S.) wave functions and the
Mandelstam formalism as well, to make ``instantaneous approximation'' to a
transition matrix element (a current operator sandwiched between two
bound-states of double heavy quarks) is described. By taking the typical
concerned decays as examples, such as $B_c$ meson decaying to $J/\psi + (\bar l
\nu)$, the advantages of the approach and its limitations are illustrated.
Finally, potential applications to various processes for possible double heavy
flavoured systems, such as those of $(Q' \bar Q)$ and $(Q' Q)$ ($m_Q, m_{Q'}\gg
\Lambda_{QCD}$), are discussed.


title:
Heavy Quark Expansion for the Inclusive Decay $\bar
  B\to\tau\,\bar\nu\,X$

abstract:
  We calculate the differential decay rate for inclusive $\bar
B\to\tau\,\bar\nu\,X$ transitions to order $1/m_b^2$ in the heavy quark
expansion, for both polarized and unpolarized tau leptons. We show that using a
systematic $1/m_b$ expansion significantly reduces the theoretical
uncertainties in the calculation. We obtain for the total branching ratio ${\rm
BR}(\bar B\to\tau\,\bar\nu\,X)=2.30\pm 0.25\%$, and for the tau polarization
$A_{\rm pol}=-0.706\pm0.006$. {}From the experimental measurement of the
branching ratio at LEP, we derive the upper bound $\lo\leq 0.8\gev^2$ for one
of the parameters of the heavy quark effective theory.


title: The Top Mass Upper Bound and Electroweak Radiative Corrections

abstract:
  We investigated the possibility of introducing sizeable negative corrections
to the $\varepsilon_{N1}$ ($\delta \rho$) parameter without affecting
$\varepsilon_{N3}$. We have found that a proper vector-like family of fermions
can imply such corrections. Differently from supersymmetry \cite{bcf}, this can
be realized without introducing light particles easily observable at LEP II.
Our example can be of particular interest if no new particle is found at LEP II
and the $\varepsilon_{N1}$ value is found to be small compared to the one
expected in the case of a large top mass.


title: Lepton flavor changing processes and CP violation in the 331 model

abstract:
  By extending the electroweak gauge group to $SU(3)_L\times U(1)_Y$, the 331
model incorporates dilepton gauge bosons $Y$ which do not respect individual
lepton family number. We point out that, in addition to family diagonal
couplings such as $Y$--$e$--$e$ that change lepton family number by two units,
dileptons may also have family non-diagonal couplings such as $Y$--$\mu$--$e$.
The latter coupling violates lepton family number by a single unit and
manifests itself via lepton flavor changing decays such as $\mu\to3e$ and
$\mu\to e\gamma$. The family non-diagonal interaction can be CP violating and
typically generates extremely large leptonic electric dipole moments. We
demonstrate a natural mechanism for eliminating both single unit lepton flavor
violation and large leptonic CP violation. Although we focus on the 331 model,
our results are applicable to other dilepton models as well, including $SU(15)$
grand unification.


title: Rare Decays of Z-boson

abstract:
  We study radiative decay modes of the Z-boson into heavy quark bound states.
We find that the widths for these decays are extremely small. We conclude that
these decays will not be detectable for the time being unless there is a
significant increase in the number of Z-bosons produced at the electron-
positron colliders.


title: Pion scattering and the skyrmion in ChPT with many pions

abstract:
  The large N effective action of the non-linear sigma model based in the coset
O(N+1)/O(N) is obtained. The renormalization of this effective action requires
the introduction of an infinite set of counterterms. However, there exit
particular cases where, at some scale, only a finite number of non-zero
coupling constants are present. This fact makes possible a one parameter fit of
the I=J=0 low-energy pion scattering. The corresponding non-local effective
action is used to study the properties of the skyrmion which is shown to be
unstable in this approximation.


title: Tumbling and Technicolor Theory

abstract:
  The extended technicolor theory is a candidate of the physics beyond the
standard model. To explain the mass hierarchy of the quarks and leptons, the
extended technicolor gauge symmetry must hierarchically break to the
technicolor gauge symmetry. Tumbling gauge theory is considered as a candidate
of the dynamics of such hierarchical symmetry breaking, since the sequential
self-breaking of the gauge symmetry (``tumbling'') can be expected in that
theory. It is well known that the extended technicolor theory induces too
strong flavor-changing neutral current interactions to be consistent with the
experiments. This problem can be solved if the technicolor dynamics is the
special one with very large anomalous dimension of the composite operator
${\bar T}T$ composed by the technifermion field $T$. Two types of the models
with large anomalous dimension have been proposed. One is the gauge theory with
slowly running coupling, another is the gauge theory with strong four fermion
interaction. It is expected that the large anomalous dimension is realized in
the tumbling gauge theory. In this thesis we systematically estimate the
strength of the effective four fermion interactions induced in the tumbling
gauge theory


title: Baryon Masses at Second Order in Chiral Perturbation Theory

abstract:
  We analyze the baryon mass differences up to second order in chiral
perturbation theory, including the effects of decuplet intermediate states. We
show that the Coleman--Glashow relation has computable corrections of order
$(m_d - m_u) m_s$. These corrections are numerically small, and in agreement
with the data. We also show that corrections to the $\Sigma$ equal-spacing rule
are dominated by electromagnetic contributions, and that the Gell-Mann--Okubo
formula has non-analytic corrections of order $m_s^2 \ln m_s$ which cannot be
computed from known matrix elements. We also show that the baryon masses cannot
be used to extract model-independent information about the current quark
masses.


title:
Finite size vertex corrections to the three-gluon decay widths of
  $J/\psi$ and $\Upsilon$ and a redetermination of $\alpha_s(\mu)$ at $\mu=m_c$
  and $m_b$

abstract:
  We calculate the corrections to the three-gluon decay widths $\Gamma_{3g}$ of
$c\bar c$ and $b \bar b$ quarkonia due to the finite extension of the $Q\bar
Q\to 3g$ vertex function. The widths computed with zero range vertex are
reduced by a factor $\gamma$ where $\gamma=0.31$ for the $J/\psi$ and
$\gamma=0.69$ for the $\Upsilon$. These large corrections necessitate a
redetermination of the values $\alpha_s(\mu)$ extracted from $\Gamma_{3g}$. We
find $\alpha_s(m_c)=0.28\pm.01$ and $\alpha_s(m_b)=0.20\pm.01$.


title: Baryogenesis from a Primordial Lepton Asymmetry

abstract:
  We examine the generation of baryon asymmetry at the weak scale from a
primordial lepton asymmetry. If the electroweak phase transition is first
order, partial reflection of tau leptons off the bubble walls and the resulting
hypercharge transport into the symmetric phase, gives rise to a baryon number
consistent with observation.


title: Effective Field Theory of Multiparticle Correlations

abstract:
  We present an effective field theory of multiparticle correlations based on
analogy with Ginzburg-Landau theory of superconductivity. We assume that the
field represents particle density fluctuations, and show that in the case of
gaussian-type effective action there are no higher-order correlations, in
agreement with the recent data. We predict that two-particle correlations have
Yukawa form. We also present our results for the two-dimensional and
one-dimensional two-particle correlations (i.e. cumulants) as projections of
our theory to lower dimensions.


title: Multiscale Technicolor and Top Production

abstract:
  Pair-production of heavy top quarks at the Tevatron Collider is significantly
enhanced by the color--octet technipion, $\eta_T$, occurring in multiscale
models of walking technicolor. We discuss $\bar tt$ rates for $m_t = 170$ GeV
and $M_{\eta_T} = 400-500$ GeV. Multiscale models also have color--octet
technirho states in the mass range 200-600 GeV that appear as resonances in
dijet production and technipion pair--production.


title: Proton-Proton Near-Forward Hard Elastic Scattering

abstract:
  We calculate the leading twist contribution to near-forward proton-proton
(and proton-antiproton) elastic scattering with large momentum transfer, in the
multiple scattering (Landshoff) mechanism. The amplitude in the near-forward
region is dominated by singlet exchange for all three valence quark-quark
scatterings. We assume the existence of a hard singlet quark-quark amplitude,
which we estimate to be ${\cal O}(\alpha_s^2/t)$. For a three-quark state whose
transverse size is less than $1/\Lambda_{\rm QCD}$, Sudakov resummation
accounts for both approximate $\d \sigma^{pp}/ \d t \sim t^{-8}$ at moderate
$t$, and $\d \sigma^{pp}/ \d t \sim t^{-10}$ at larger $t$. The transition from
approximate $t^{-8}$ to $t^{-10}$ behavior is strongly correlated with the
transverse size of the valence three-quark state in the proton.


title:
Unification of couplings and soft supersymmetry breaking terms in 4D
  superstring models

abstract:
  We consider the predictions for the hierarchy of mass scales, the fine
structure constant, the radii of compactification and the soft SUSY breaking
terms which follow if SUSY breaking is triggered by a gaugino condensate.


title: Unification Scale in String Theory

abstract:
  We study the unification scale and gauge coupling constant in 4D string
theory. We show that the fine structure constant is determined by the dimension
of the hidden gauge group and only $SU(6)$ and $SO(9)$ are consistent with
minimal string unification while the unification scale can be of order of
$10^{16}\,GeV$.


title: Phenomenological implications from moduli fields in strings

abstract:
  We study some phenomenological consequences of having moduli fields with
large vacuum expectation values (v.e.v.). The v.e.vs of the moduli are
dynamically determined once supersymmetry is broken in 4D string theories. The
study constraints the possible Yukawa interactions and modular weights for
matter fields.


title:
Two-loop renormalization group equations for soft SUSY breaking scalar
  interactions: supergraph method

abstract:
  We obtain the one- and two-loop renormalization group equations for soft SUSY
breaking scalar interactions in general, semi-simple SUSY gauge model, by using
the supergraph method. We find that the method simplifies the calculation
significantly because of the non-renormalization theorem and also because of
the property that the relevant divergences are derived by simple algebra from
those in exact SUSY case. A disagreement with the existing result is found in
$\beta^{(2)}(m^2)$ and its cause is briefly discussed.


title: Searching a doubly charged Higgs boson at Hera

abstract:
  The production of a single exotic Higgs particle is studied at Hera. Within
the present limits on the Yukawa couplings this doubly charged particle,
suggested by the left-right symmetric models, can be observed at Hera up to
values of its mass of about 150 GeV.


title:
Observations Concerning the Magnitude of t \bar{t} Threshold Effects on
  Electroweak Parameters

abstract:
  We discuss a recent analysis of $t\bar{t}$ threshold effects and its
implications for the determination of electroweak parameters. We show that the
new formulation, when applied to the $\rho$ parameter for $m_t\approx158$~GeV,
gives a result of similar magnitude to those previously obtained. In fact, it
is quite close to our ``resonance'' calculation. We also present a simple
estimate of the size of the threshold effects based on an elementary Bohr-atom
model of $t\bar{t}$ resonances.


title: Evidence for a Hard Pomeron in Perturbative QCD

abstract:
  The $t$-channel exchange of two gluons in a color singlet state represents
the lowest order approximation to the Pomeron. This exchange mechanism is
thought to also explain the formation of rapidity gaps in dijet events at the
Tevatron. At the perturbative level this requires suppressed gluon emission in
the rapidity interval between widely separated jets, analogous to color
coherence effects in $t$-channel photon exchange. By calculating the imaginary
part of the two gluon, color singlet exchange amplitude we show how this
pattern does emerge for gluon emission at small transverse momenta. At large
$p_T$ the radiation pattern characteristic for color octet single gluon
exchange is reproduced.


title: Kaon-Nucleon Scattering from Chiral Lagrangians

abstract:
  The s-wave $K^{\pm}N$ scattering amplitude is computed up to one-loop order
corresponding to next-to-next-to-leading order (or N$^2$LO in short) with a
heavy-baryon effective chiral Lagrangian. Constraining the low-energy constants
by on-shell scattering lengths, we obtain contributions of each chiral order up
to N$^2$LO and find that the chiral corrections are ``natural" in the sense of
viable effective field theories. We have also calculated off-shell $s$-wave
$K^-N$ scattering amplitudes relevant to kaonic atoms and $K^-$ condensation in
``nuclear star" matter including the effect of $\Lambda (1405)$. The $K^-p$
amplitude is found to be quite sensitive to the intermediate $\Lambda (1405)$
contribution, while the $K^-n$ amplitude varies smoothly with the C.M. energy.
The crossing-even one-loop corrections are found to play an important role in
determining the higher-order chiral corrections.


title: Phenomenological Constraints on $\bar\Lambda$ and $\lambda_1$

abstract:
  Combining the experimental data on the inclusive decays $D\to X\,e\,\nu$,
$B\to X\,e\,\nu$ and $B\to X\,\tau\,\nu$, we find severe constraints on the
$\bar\Lambda$ and $\lambda_1$ parameters of the Heavy Quark Effective Theory.
In particular, we get $\bar\Lambda<0.7\,$GeV. Our constraints further imply
$m_c\geq1.43\,$GeV and $m_b\geq4.66\,$GeV. We discuss future prospects of
improving these bounds and their phenomenological implications.


title: Cosmic Strings at the Electroweak Phase Transition

abstract:
  If cosmic strings are present at the electroweak phase transition, they can
act as seeds on which bubbles of true vacuum nucleate. We explore the nature of
such a phase transition, in particular the wall velocity and thickness of the
bubbles. {}From the viewpoint of electroweak baryogenesis, adiabatic conditions
exist in the expanding bubble walls, and such models of baryogenesis can be
successfully applied. In the present mechanism, the nature of the electroweak
phase transition is insensitive to the other details of the model, thus
reducing the uncertainties in the estimate of net baryon asymmetry.


title: LEP Electroweak Physics

abstract:
  This is an overview of the electroweak physics achieved at LEP. After a brief
review of the standard model and the calculation of the radiative corrections
both in the MS and on-shell schemes, we introduce the Z decay parameters around
the resonance energy and discuss the status of the standard model fits for
them, along with some selected highlights of the measurements as well as new
particle searches.


title: Calculating Fragmentation Functions from Definitions

abstract:
  Fragmentation functions for hadrons composed of heavy quarks are calculated
directly from the definitions given by Collins and Soper and are compared with
those calculated in another way. A new fragmentaion function for a P-wave meson
is also obtained and the singularity arising at the leading order is discussed.


title: Model for a Light Z' Boson

abstract:
  A model of a light $Z'$ boson is constructed and phenomenological bounds are
derived. This $Z'$ boson arises from a very simple extension to the Standard
Model, and it is constrained to be light because the vacuum expectation values
which generate its mass also break the electroweak gauge group. It is difficult
to detect experimentally because it couples exclusively or primarily (depending
on symmetry breaking details) to second and third generation leptons. However,
if the $Z'$ boson is sufficiently light, then there exists the possibility of
the two-body decay $\tau \rightarrow \mu Z'$ occuring. This will provide a
striking signature to test the model.


title: Radiative Lepton Masses with Heavy Lepton Seed

abstract:
  We construct a $Z_8$ model for leptons where all Yukawa couplings are of
order unity, but known lepton masses are generated radiatively, {\it order by
order}. The seed is provided by fourth generation leptons $E$ and $N$, which
receive (Dirac) mass in usual way. Two additional Higgs doublets with
nontrivial $Z_8$ charge are introduced to give nearest neighbor Yukawa
couplings. Hence, nonstandard Higgs bosons are flavor changing in an unusual
way. Loop masses are generated when $Z_8$ is {\it softly} broken down to $Z_2$.
However, $e$ and $\mu$ mass generation require new Higgs bosons to be at weak
scale. Neutral scalar mixing underlies $m_\mu/m_\tau \gg m_e/m_\mu$,
$m_\tau/m_E$. The $Z_2$ symmetry forbids $\mu\to e\gamma$ and $\tau\to
\mu\gamma$. The most stringent bound comes from $\tau\to \mu\mu^\pm e^\mp$. The
model has interesting implications for $\tau\to e\gamma$, $\mu \bar e \to
\bar\mu e$ conversion, $\mu\to e\nu_e\bar\nu_\mu$, and FCNC decays of $E$ and
$N$ (such as $E\to \tau e^\pm\mu^\mp$).


title: A new Method for Computing One-Loop Integrals

abstract:
  We present a new program package for calculating one-loop Feynman integrals,
based on a new method avoiding Feynman parametrization and the contraction due
to Passarino and Veltman. The package is calculating one-, two- and three-point
functions both algebraically and numerically to all tensor cases. This program
is written as a package for Maple. An additional Mathematica version is planned
later.


title: A phenomenological Theory of Fermion Masses and Mixings

abstract:
  A phenomenological theory of fermion masses and mixings is constructed within
the framework of a four- family symmetry. It is found that the most favored set
of relevant CKM elements are $|V_{us}|\approx 0.222$, $|V_{cb}|\approx 0.044$,
$|V_{ub}/V_{cb}|\approx 0.082$, $|V_{ud}|\approx 0.974$, $|V_{cs}|\approx
0.9736$, $|V_{cd}|\approx 0.224$ with $\hat{B}_K \approx 0.8$. The top quark
mass is predicted to be 258 GeV at 1 GeV with its physical mass approximately
equal to 153 GeV. The Majorana scale associated with the fourth neutrino is
bound from above to be 6.4 TeV.


title: The b -> s gamma decay revisited

abstract:
  In this work we compute the leading logarithmic corrections to the b -> s
gamma decay in a dimensional scheme which does not require any definition of
the gamma5 matrix. The scheme does not exhibit unconsistencies and it is
therefore a viable alternative to the t'Hooft Veltman scheme, particularly in
view of the next-to-leading computation. We confirm the recent results of
Ciuchini et al.


title: A Parton Model for Inclusive Semileptonic B Meson Decays

abstract:
  The parton model for semileptonic B meson decays is studied with special
attention to the decay distributions. We find that the spectra show dramatic
variations when we introduce cuts on the hadronic energy or invariant mass of
hadrons. Results for both $b\rightarrow u$ and $b\rightarrow c$ decays are
presented. The detailed spectra may help to separate the two types of decays.


title: Systematics of Exclusive B-decays

abstract:
  Systematic analysis of the high recoil decay channels of the B-meson, two
body mesonic decay channels in particular. For decays involving D-mesons, all
experimentally observed rates are in reasonable accord with our calculations.
Noticeable corrections to heavy quark symmetry are found, appearing most
prominently when comparing D and D* decay modes. Calculated branching ratios
involving the CKM matrix element V_{ub} are all below experimental upper
bounds, but not markedly so. Calculated decay rates into charmonium lie a bit
on the low side. Where color-suppressed diagrams contribute, they are found to
be also suppressed dynamically and explicit calculation shows that the
color-suppressed diagrams are ignorable in B to D pi decays.


title:
Instanton - like transitions at high energies in (1+1) dimensional
  scalar models. II.Classically allowed induced vacuum decay

abstract:
  We consider classical Minkowskian solutions to the field equation in the
(1+1) dimensional scalar model with the exponential interaction that describe
the unsuppressed false vacuum decay induced by $n$ initial particles. We find
that there is a critical value of $n$ below which there are no such solutions,
i.e., the vacuum decay is always suppressed. For the number of initial
particles larger than this value the vacuum decay is unsuppressed at high
enough energies.


title: Automatic Generation of Tree Level Helicity Amplitudes

abstract:
  The program MadGraph is presented which automatically generates postscript
Feynman diagrams and Fortran code to calculate arbitrary tree level helicity
amplitudes by calling HELAS[1] subroutines. The program is written in Fortran
and is available in Unix and VMS versions. MadGraph currently includes standard
model interactions of QCD and QFD, but is easily modified to include additional
models such as supersymmetry.


title: Decays of a fermiophobic Higgs

abstract:
  We explore the phenomenology of a fermiophobic Higgs: a Higgs whose couplings
to fermions are suppressed. We calculate the branching ratios of a Higgs
decaying to $\gamma\gamma$, $W^*W^*$, $Z^*Z^*$, $Zb\bar b$, $Z\gamma$, $\gamma
b\bar b$, and final states involving vector mesons like $\Upsilon$, $J/\Psi$
and $\rho$. In order to calculate these branching ratios we perform a complete
one-loop renormalization of the vertices $HZ\gamma$ and $H\gamma\gamma$. The
decay mode $H\rightarrow \gamma\gamma$ is near unity for a Higgs below the $W$
mass, which provides a clean way of discovering a light fermiophobic Higgs.
Interesting modes involving the vector mesons $Z$, $\gamma$, $\rho$, $J/\Psi$,
and $\Upsilon$ are carefully analyzed.


title: Identifying Unconventional E$_{\bf 6}$ Models at $e^+ e^-$ Colliders

abstract:
  Recently it was shown that, in the framework of superstring inspired $\E$
models, the presence of generation dependent discrete symmetries allows us to
construct a phenomenologically viable class of models in which the three
generations of fermions do not have the same embedding within the fundamental
{\bf 27} dimensional representation of E$_6$. In this scenario, these different
embeddings of the conventional fermions imply that the left-handed charged
leptons and the right-handed $d$-type quarks are coupled in a non--universal
way to the new neutral gauge bosons $(Z_\theta)$ present in these models. It
was also shown that a unique signature for this scenario, would be a deviation
from unity for the ratio of cross sections for the production of two different
lepton species in $e^+e^-$ annihilation. However, several different scenarios
are possible, depending on the particular assignment chosen for $e_L$, $\mu_L$
and $\tau_L$ and for the right-handed $d$-type quarks, as well as on the type
of $Z_\theta$ boson. Such scenarios can not be disentangled from one another by
means of cross section measurements alone. In this paper we examine the
possibility of identifying the pattern of embeddings through measurements of
polarized and unpolarized asymmetries for fermion pair-production at the 500
GeV $e^+e^-$ Next Linear Collider (NLC). We show that it will be possible to
identify the different patterns of unconventional assignments for the
left-handed leptons and for the $b_R$ quark, for $Z_\theta$ masses as large as
$\sim 1.5$ TeV.


title:
Ground State Properties and Glueball Spectrum in SU(2) Yang-Mills Theory
  using Gauge Invariant Variables

abstract:
  We describe a nonperturbative calculation of the spectrum of SU(2) Yang-Mills
theory based on a Hamiltonian formulation. Our approach exploits gauge
invariant variables similar to those used in nuclear physics to describe
collective motion in nuclei.


title: On SUSY Dark Matter Detection with Spinless Nuclei

abstract:
  We investigate the role of nuclear spin in elastic scattering of Dark Matter
(DM) neutralinos from nuclei in the framework of the Minimal SUSY standard
model (MSSM). The relative contribution of spin-dependent axial-vector and
spin-independent scalar interactions to the event rate in a DM detector has
been analyzed for various nuclei. Within general assumptions about the nuclear
and nucleon structure we find that for nuclei with atomic weights $A > 50$ the
spin-independent part of the event rate $R_{si}$ is larger than the
spin-dependent one $R_{sd}$ in the domain of the MSSM parameter space allowed
by the known experimental data and where the additional constraint for the
total event rate $R =R_{sd} + R_{si} > 0.01$ is satisfied. The latter reflects
realistic sensitivities of present and near future DM detectors. Therefore we
expect equal chances for discovering the DM event either with spin-zero or with
spin-non-zero isotopes if their atomic weights are $A_{1} \sim A_{2} > 50$.


title: Tests of isospin symmetry breaking at $\phi (1020)$ meson factories

abstract:
  In a model of isospin symmetry breaking we obtain the ($e^{-} e^{+}
\rightarrow \pi^{-} \pi^{+}$) amplitude $Q$ and the isospin $I=0$ and $I=1$
relative phase $\psi$ at the $\phi (1020)$ resonance in aproximate agreement
with experiment. The model predicts $\Gamma(\phi \rightarrow \omega \pi^{0})
\approx 4 \cdot 10^{-4} \;\mbox{MeV}$. We have also obtained $\Gamma (\phi
\rightarrow \eta' \gamma)=5.2 \cdot 10^{-4} \;\mbox{MeV}$. Measuring this
partial width would strongly constrain $\eta$-$\eta'$ mixing. The branching
ratios $BR$ of the isospin violating decays $\rho^{+} \rightarrow \pi^{+} \eta$
and $\eta' \rightarrow \rho^{\pm} \pi^{\mp}$ are predicted to be $BR(\rho^{+}
\rightarrow \pi^{+} \eta)=3 \cdot 10^{-5}$ and $BR(\eta' \rightarrow \rho^{\pm}
\pi^{\mp})=4 \cdot 10^{-3}$, respectively, leading to $BR[\phi \rightarrow
\rho^{\pm} \pi^{\mp} \rightarrow (\pi^{\pm} \eta)\pi^{\mp} \rightarrow
(\pi^{\pm} \gamma \gamma)\pi^{\mp}]=10^{-6}$ and $BR[\phi \rightarrow \eta'
\gamma \rightarrow (\rho^{\pm} \pi^{\mp})\gamma]=2\cdot 10^{-6}$.


title:
Polarized deep inelastic scattering at high energies and parity
  violating structure functions

abstract:
  A comprehensive analysis of deep inelastic scattering of polarized charged
leptons on polarized nucleons is presented; weak interaction contributions,
both in neutral and charged current processes, are taken into account and the
parity violating polarized nucleon structure functions are studied. Possible
ways of their measurements and their interpretations in the parton model are
discussed.


title: Electroweak Baryogenesis in the Adiabatic Limit

abstract:
  Electroweak baryogenesis can occur in the ``adiabatic limit,'' in which
expanding bubbles of true vacuum are assumed to have rather thick walls and be
slowly moving. Here the problem of calculating the baryon asymmetry in this
limit is reconsidered.
  A simple prescription for obtaining the relevant kinetic equations is given.
An additional suppression beyond that usually assumed is found.
  This arises because the generation of an asymmetry requires violation of
approximately conserved currents by Higgs expectation values, which are small
near the front of the walls.
  As applications, the asymmetries in multi-Higgs models and the minimal
supersymmetric standard model are estimated to be proportional to $\alpha_w^8$
and $\alpha_w^6$ respectively.
  Also, in this limit the baryon asymmetry in the Minimal Standard Model is
extraordinarily small.


title:
Production of Jet Pairs at Large Relative Rapidity in Hadron-Hadron
  Collisions as a Probe of the Perturbative Pomeron

abstract:
  The production of jet pairs with small transverse momentum and large relative
rapidity in high energy hadron-hadron collisions is studied. The rise of the
parton-level cross section with increasing rapidity gap is a fundamental
prediction of the BFKL `perturbative pomeron' equation of Quantum
Chromodynamics. However, at fixed collider energy it is difficult to
disentangle this effect from variations in the cross section due to the parton
distributions. It is proposed to study instead the distribution in the
azimuthal angle difference of the jets as a function of the rapidity gap. The
flattening of this distribution with increasing dijet rapidity gap is shown to
be a characteristic feature of the BFKL behaviour. Predictions for the Fermilab
proton-antiproton collider are presented.


title: Couplings of heavy hadrons with soft pions from QCD sum rules

abstract:
  We estimate the couplings in the Heavy Hadron Chiral Theory (HHCT) lagrangian
from the QCD sum rules in an external axial field. Stability of the sum rules
at moderate values of the Borel parameter is poor that probably signals a slow
convergence of the OPE series. At large values of the Borel parameter they
stabilize, and yield the couplings much lower than the constituent quark model
expectations. This region is not trustworthy for baryons, but in the meson case
only unexpectedly large contributions of a few lowest excitations could
invalidate the prediction $g_1\approx0.2$.


title: Effectively Semi-Relativistic Hamiltonians of Nonrelativistic Form

abstract:
  We construct effective Hamiltonians which despite their apparently
nonrelativistic form incorporate relativistic effects by involving parameters
which depend on the relevant momentum. For some potentials the corresponding
energy eigenvalues may be determined analytically. Applied to two-particle
bound states, it turns out that in this way a nonrelativistic treatment may
indeed be able to simulate relativistic effects. Within the framework of hadron
spectroscopy, this lucky circumstance may be an explanation for the sometimes
extremely good predictions of nonrelativistic potential models even in
relativistic regions.