title: Large Scale Structure and Supersymmetric Inflation without Fine Tuning

abstract:
  We explore constraints on the spectral index $n$ of density fluctuations and
the neutrino energy density fraction $\Omega_{HDM}$, employing data from a
variety of large scale observations. The best fits occur for $n\approx 1$ and
$\Omega_{HDM} \approx 0.15 - 0.30$, over a range of Hubble constants $40-60$ km
s$^{-1}$ Mpc$^{-1}$. We present a new class of inflationary models based on
realistic supersymmetric grand unified theories which do not have the usual
`fine tuning' problems. The amplitude of primordial density fluctuations, in
particular, is found to be proportional to $(M_X /M_P)^2$, where $M_X (M_P)$
denote the GUT (Planck) scale, which is reminiscent of cosmic strings! The
spectral index $n = 0.98$, in excellent agreement with the observations
provided the dark matter is a mixture of `cold' and `hot' components.


title:
$D^*$ Radiative Decays and Strong Coupling of Heavy Mesons with Soft
  Pions in a QCD Relativistic Potential Model

abstract:
  In the framework of a QCD inspired relativistic potential model, we evaluate
radiative decay rates of heavy mesons and their coupling with soft pions. The
agreement with the existing experimental data is satisfactory. In the limit
$m_Q \to \infty$ one obtains results in agreement with the Heavy Quark
Effective Theory and is able to predict the values of the relevant couplings;
in particular, for the scaled $B^*B \pi$ strong coupling constant $g$, we find
that the non relativistic constituent quark model prediction $g=1$ is modified,
by the inclusion of the relativistic effects due to the light quarks, to the
value $g=1/3$, in agreement with recent QCD sum rules determination.


title: Production of Pairs of Sleptoquarks in Hadron Colliders

abstract:
  We calculate the cross section for the production of pairs of scalar
leptoquarks (sleptoquarks) in a supersymmetric $E_6$ model, at hadron
colliders. We estimate higher order corrections by including $\pi^2$ terms
induced by soft-gluon corrections. Discovery bounds on the sleptoquark mass are
estimated at collider energies of 1.8, 2, and 4 TeV (Tevatron), and 16 TeV
(LHC).


title:
Electroweak Sphaleron For Effective Theory In The Limit Of Large Higgs
  Boson Mass

abstract:
  Theoretical arguments suggest that the Higgs sector of the standard model is
an effective theory. We parametrize the new physics by means of an effective
Lagrangian technique and study its effect on the energy of the electroweak
sphaleron. We found that in the presence of a certain class of higher dimension
operators the sphaleron energy becomes arbitrarily large as the Higgs boson
mass increases. The physical meaning of this result and its implications to the
electroweak baryogenesis in the dynamical models are discussed.


title: In Search of Classical Trajectories

abstract:
  This short talk summarizes some important issues relevant to a new Minkowski
space formulation of nonperturbative contributions to quantum scattering.
Details may be found in hep-ph/9403353. (To appear in Proceedings of 1994 NATO
Advanced Research Workshop)


title: Bounds on $g_5^Z$ from Precision LEP Measurements

abstract:
  The parity violating but CP conserving anomalous three-gauge-boson coupling
$g_5^Z$ induces a universal contribution to the left-handed coupling of the $Z$
boson to fermions. We find that the LEP measurements of the partial $Z$ widths
and lepton forward-backward asymmetries are sufficiently precise to place a
bound of order $|g_5^Z|$ less than $\sim~10\%$. This bound is significantly
better than what can be obtained at present from rare $K$ and $B$ meson decays.


title: Low-x Structure Functions

abstract:
  QCD predictions on the low-$x$ behaviour of the structure functions are
reviewed and compared with the recent measurements of $F_2(x,Q^2)$ at HERA. The
present theoretical accuracy of these predictions is discussed.


title: Low Energy Parameters of the KK and Pipi Scalar-Isoscalar Interactions

abstract:
  Threshold expansions of the $\pi\pi$ and $K\overline{K}$ spin 0 and isospin 0
scattering amplitudes are performed. Scattering lengths, effective ranges and
so--called volume parameters are evaluated. Good agreement with the existing
experimental data for the $\pi\pi$ scalar--isoscalar amplitude is found. An
importance of future accurate measurements of the $K\overline{K}$ threshold
parameters is stressed. New data are needed to understand the basic features of
the scalar mesons.


title: A New Solution of the Solar Neutrino Flux

abstract:
  We report a new solution to explain the observed deficit of the solar
neutrino flux by Homestake, Kamiokande II and III, GALLEX and SAGE experiments.
We use the matter mixing and the helicity oscillation in the twisting magnetic
fields in the sun. Our model predicts the short (seasonal) and long (11 years)
time variations of the solar neutrino flux. Three kinds of data observed by
Homestake, Kamiokande, GALLEX and SAGE detectors are reproduced well if the
mixing angle and the squared mass difference are in the small area around
$\sin^2 2\theta \simeq 0.01$ and $\Delta m^2\simeq 1.3\times 10^{-8}{\rm
eV}^2$.


title:
Automatically R-Conserving SUSY SO(10) Models and Mixed Light Higgs
  Doublets

abstract:
  In automatic R-parity conserving SO(10) models, the simplest way to
accomodate realistic fermion masses is to demand that that the light Higgs
doublets be linear combinations of the {10} and {126}-bar grand unified Higgs
representations. We study the realization of this mixed light Higgs property
consistent with doublet-triplet splitting in a minimal model and discuss its
predictions for neutrino masses and implications for proton decay.


title: Mass of the charm-quark from QCD sum rules

abstract:
  Relativistic and non-relativistic ratios of Laplace transform QCD moment sum
rules for charmonium are used in order to determine the value of the on-shell
charm-quark mass. The validity of the non-relativistic version of QCD sum rules
in this particular application is discussed. After using current values of the
perturbative and non-perturbative QCD parameters, as well as experimental data
on the $J/\psi$ system, we obtain $m_{c}(Q^{2}=m_{c}^{2}) = 1.46 \pm 0.07
\;\mbox{GeV}$.


title: Search for New Physics in e-e- Scattering

abstract:
  Considering the physics potential of an e-e- collider in the TeV energy
range, we indicate a few interesting examples for exotic processes and discuss
the standard model backgrounds. Focussing on pair production of weak gauge
bosons, we report some illustrative predictions.


title: Hadron collider limits on anomalous $WW\gamma$ couplings

abstract:
  A next-to-leading log calculation of the reactions $pp$ and
$p\overline{p}\rightarrow W^\pm\gamma X$ is presented including a tri-boson
gauge coupling from non-Standard Model contributions. Two approaches are made
for comparison. The first approach considers the tri-boson $WW\gamma$ coupling
as being uniquely fixed by tree level unitarity at high energies to its
Standard Model form and, consequently, suppresses the non-Standard Model
contributions with form factors. The second approach is to ignore such
considerations and calculate the contributions to non-Standard Model tri-boson
gauge couplings without such suppressions. It is found that at Tevatron
energies, the two approaches do not differ much in quantitative results, while
at Large Hadron Collider (LHC) energies the two approaches give significantly
different predictions for production rates. At the Tevatron and LHC, however,
the sensitivity limits on the anomalous coupling of $WW\gamma$ are too weak to
usefully constrain parameters in effective Lagrangian models.


title: Interaction of Wilson Loops in the SU(N) Gauge Theory

abstract:
  The average of two Wilson loops is expressed in terms of gauge invariant
field strength correlators. Assuming the existence of finite correlation length
$T_g$ and taking into account the absence of a fixed direction in colour space,
we generalize the area law asymptotics for the case of the average of two
Wilson loops embedded into the same plane. The results are presented in terms
of averaged single Wilson loop operators in irreducible representations which
correspond to the geometry of the contours. A special reduction of our results
(obtained for arbitrary dimensionality of space-time) to the case of
two-dimensional SU(N) theory is performed and the connection to the results
existing in literature is established.


title: SO(10) SUSY GUTs and Fermion Masses

abstract:
  In this talk~\footnote{Talk presented at the IFT Workshop on Yukawa
Couplings, Gainesville, FL, February 1994.} I summarize published work on a
systematic operator analysis for fermion masses in a class of effective
supersymmetric SO(10) GUTs \cite{adhrs}~\footnote{This work is in collaboration
with G. Anderson, S. Dimopoulos, L.J. Hall, and G. Starkman.}. Given a minimal
set of four operators at $M_G$, we have just 6 parameters in the fermion mass
matrices. We thus make 8 predictions for the 14 low energy observables (9 quark
and charged lepton masses, 4 quark mixing angles and $\tan \beta$). Several
models, i.e. particular sets of dominant operators, are in quantitative
agreement with the low energy data.
  In the second half of the talk I discuss the necessary ingredients for an
SO(10) GUT valid below the Planck (or string) scale which reproduces one of our
models. \footnote{These are preliminary results of work in progress with
Lawrence Hall.} This complete GUT should still be interpreted as an effective
field theory, i.e. perhaps the low energy limit of a string theory.}


title: B To Light Meson Form Factors

abstract:
  The heavy to light form factors in $B$ decays are discussed. Critical
discussion of theoretical approaches is made with special emphasis on their
failure to describe the $B \to K^{(\ast )}\psi$ data.


title:
Non Standard Tau Pair Production in Two Photon Collisions at LEP II and
  Beyond

abstract:
  We study the sensitivity of LEP II and NLC, via two photon collisions, to the
effects of anomalous $\tau \overline{\tau} \gamma$ couplings. We also discuss
some CP-odd observables that can be useful to disentangle the contributions
from the anomalous couplings. (5 figures included via epsf appended at the end
as uuencoded compressed tar postscript file).


title: The Z Line-shape in the Standard Model

abstract:
  The status of the theoretical uncertainties for LEP1 observables associated
with the corresponding comparison among different codes is briefly reviewed.


title:
Possible Detection of a Higgs Boson at Higher Luminosity Hadron
  Colliders

abstract:
  We have examined how a Standard Model or Supersymmetric Higgs boson h might
be detected at possible hadron colliders. The channels W(to ell nu)h(to b b~),
Z(to ell ell~)h(to b b~) and W/Z(to jets)h(to tau+ tau-) are most useful. The
results imply that h with mass M_h can be detected or excluded for M_h between
about 80--130 GeV at any hadron collider with energy greater or similar to 2
TeV and an integrated luminosity greater or similar to 10 fb^{-1}; high
luminosity is the essential requirement. We comment on measuring $h$ couplings
and branching ratios.


title: Heavy Meson Radiative Decays and Light Vector Meson Dominance

abstract:
  Electromagnetic interactions are introduced in the effective chiral
Lagrangian for heavy mesons which includes light vector particles. A suitable
notion of vector meson dominance is formulated. The constraints on the heavy
meson -light vector and heavy meson-light pseudoscalar coupling constants are
obtained using experimental $D^* \ra D \, \gamma $ branching ratios. These
constraints are compared with values estimated from semi-leptonic transition
amplitudes as well as from extension of the light meson coupling pattern.
Application to the heavy baryon spectrum in the ``bound state " model is made.


title: $B_c$ spectroscopy

abstract:
  In the framework of potential models for heavy quarkonium the mass spectrum
for the system ($\bar b c$) is considered. Spin-dependent splittings, taking
into account a change of a constant for effective Coulomb interaction between
the quarks, and widths of radiative transitions between the ($\bar b c$) levels
are calculated. In the framework of QCD sum rules, masses of the lightest
vector $B_c^*$ and pseudoscalar $B_c$ states are estimated, scaling relation
for leptonic constants of heavy quarkonia is derived, and the leptonic constant
$f_{B_C}$ is evaluated.


title:
Semi-Analytical Approach to Four-Fermion Production in $e^+ e^-$
  Annihilation

abstract:
  A study of the semi-analytical approach to four-fermion production in $e^+
e^-$ annihilation is presented. We classify all possible four-fermion final
states and present results of new calculations for the `basic' processes with
the $WW,ZZ$, and $ZH$ off-shell production together with some examples of
`background' processes. The Initial State Radiative corrections are included
for the basic processes. Several numerical examples are given in the energy
range from LEP2 up to $\sqrt{s}=1$ TeV.


title: B Decays, an Introductory Survey

abstract:
  To start the $b$-decay session we briefly introduce and comment some
important theoretical tools which are currently used in $b$ physics. Heavy
Quark Symmetry and its consequences for heavy to heavy and heavy to light
semi-leptonic decays, as well as for leptonic decays, are briefly summarised.
It is stressed that symmetry must be completed with dynamical calculations. A
critical discussion of the nearest pole dominance (VMD) assumption is
performed. Parton model and its higher twist corrections are discussed on the
example of lifetimes. Finally non-leptonic decays are considered via the
example of the exclusive calculation of $\Delta \Gamma$ in the $B_s-\overline
B_s$ system. The popular factorization assumption is discussed and seems to be
rather good.


title:
Structure Dependence in $\pi \to \bf\ell\nu, \pi\ to \ell\nu\gamma$ and
  $\pi^0\ to \gamma\gamma$ Decays

abstract:
  The amplitudes of $\pi$-meson decays are calculated in a relativistic
nonperturbative quark model which assumes that mesons are made of a quark
antiquark pair and of a scalar neutral component representing the contribution
of the nonelementary fluctuations of the quark gluonic field. The experimental
data can be fitted in a satisfactory manner using current quark masses
$m_u\approx1.5\ MeV, m_d\approx9\ MeV$.


title:
Cosmic Strings and Electroweak Symmetry Restoration in the Two-Higgs
  Doublet Model

abstract:
  We investigate the region of restored electroweak symmetry around a
superconducting cosmic string coupled to the Weinberg-Salam model with an extra
Higgs doublet. We show that the presence of the extra Higgs fields, and in
particular their CP violating relative phase, does not qualitatively affect the
results of Perkins and Davis[1] obtained for the standard electroweak theory.
This result is neccessary to ensure the validity of some recently proposed
string-mediated electroweak baryogenesis scenarios.


title: Top-Quark Production and Flavor Physics

abstract:
  Because of the top quark's very large mass, about 175~GeV, it now provides
the best window into flavor physics. Thus, pair--production of top quarks at
the Tevatron Collider is the best probe of this physics until the Large Hadron
Collider turns on in the next century. I will discuss aspects of the mass and
angular distributions that can be measured in $\ttb$ production with the coming
large data samples from the Tevatron and even larger ones from the LHC.


title: Diffusion Enhances Spontaneous Electroweak Baryogenesis

abstract:
  We include the effects of diffusion in the electroweak spontaneous
baryogenesis scenario and show that it can greatly enhance the resultant baryon
density, by as much as a factor of $1/\alpha_w^4 \sim 10^6$ over previous
estimates. Furthermore, the baryon density produced is rather insensitive to
parameters characterizing the first order weak phase transition, such as the
width and propagation velocity of the phase boundary.


title: Constraints on the minimal supergravity model from the b->s+\gamma decay

abstract:
  The constraints on the minimal supergravity model from the b->s+\gamma decay
are studied. A large domain in the parameter space for the model satisfies the
CLEO bound, BR(b->s+\gamma)<5.4X10^{-4}. However, the allowed domain is
expected to diminish significantly with an improved bound on this decay. The
dependence of the b->s+\gamma branching ratio on various parameters is studied
in detail. It is found that, for A_t<0 and the top quark mass within the
vicinity of the center of the CDF value, m_t^{pole}=174\pm17 GeV, there exists
only a small allowed domain because the light stop is tachyonic for most of the
parameter space. A similar phenomenon exists for a lighter top and A_t negative
when the GUT coupling constant is slightly reduced. For A_t>0, however, the
branching ratio is much less sensitive to small changes in m_t, and \alpha_G.


title: Vector Leptoquarks Could Be Rather Light?

abstract:
  Some low-energy manifestations of a minimal extension of the Standard Model
based on the quark-lepton $SU(4)_V \otimes SU(2)_L \otimes G_R$ symmetry of the
Pati-Salam type are analysed. Given this symmetry a new type of mixing in the
quark-lepton interactions is shown to be required. An additional arbitrariness
of the mixing parameters could allow to decrease noticeably the lower bound on
the leptoquark mass $M_X$ originated from the $\pi$ and $K$ decays and the $\mu
e$ conversion. The only mixing independent bound emerging from the cosmological
limit on the $\pi^0 \rightarrow \nu \bar{\nu}$ decay width is $M_X > 18~TeV$.


title: Direct $CP$ Violation in a Variety of $B$ Decays

abstract:
  We give a brief review of direct $CP$ violation effects in charmless $B$
decays, both at the inclusive and at the exclusive level. It is emphasized that
typical exclusive final states are composed of 2--4 $K$ or $\pi$'s, hence
particle identification (in terms of $K/\pi$ separation) is of crucial
importance for studying $CP$ violation in these modes. Another kind of
``charmless" final state is also emphasized: $b\to dc\bar c$. The decay rate is
tree dominant, while ``$q^2$" is necessarily above $c\bar c$ threshold hence in
the domain of perturbative QCD. The $CP$ asymmetry is therefore relatively
clean and reliable. Theoretically, a few $\times 10^7$ $B$'s would suffice if
one could accumulate modes like $B^+\to D^{+\left(*\right)} \bar
D^{0\left(*\right)}$. [To appear in proceedings of ``The Third KEK Topical
Conference on
  CP Violation --- Its Implications to Particle Physics and Cosmology'',
  16--18 November, 1993, KEK, Tsukuba, Japan (Eds. Y. Kuno and Y. Okada).]


title: Comments on the Standard Model of Electroweak Interactions

abstract:
  The Standard Model of electroweak interactions is shown to include a gauge
theory for the observed scalar and pseudoscalar mesons. This is done by
exploiting the consequences of embedding the SU(2)left X U(1) group into the
chiral group of strong interactions and by considering explicitly the Higgs
boson and its three companions inside the standard scalar 4-plet as composite.
No extra scale of interaction is needed. Quantizing by the Feynman path
integral reveals how, in the `Nambu Jona-Lasinio approximation', the quarks and
the Higgs boson become unobservable, and the theory anomaly-free. Nevertheless,
the `anomalous' couplings of the pseudoscalar mesons to gauge fields spring
again from the constraints associated with their compositeness itself. This
work is the complement of a previous one, ref.[1], where the leptonic sector
was shown to be compatible with a purely vectorial theory and, consequently, to
be also anomaly-free. The bond between quarks and leptons loosens.


title: The small $x$ behaviour of $g_1$

abstract:
  We discuss the small $x$ behaviour of the spin dependent structure function
$g_1$. We find a contribution from the exchange of two non-perturbative gluons
which behaves as $\sim ( 2 \ln {1 \over x} -1)$.


title: Generation Permutation Symmetry and the Quark Mixing Matrix

abstract:
  We propose a new discrete symmetry in the generation space of the fundamental
fermions, consistent with the observed fermion mass spectrum. In the case of
the quarks, the symmetry leads to the unique prediction of a flat CKM matrix at
high energy. We explore the possibility that evolution due to quantum
corrections leads to the observed hierarchical form of the CKM matrix at low
energies.


title: Heavy Flavours Leptonic and Semi-leptonic Decays on the Lattice

abstract:
  We present some results of the {\bf{ELC}} (European Lattice Collaboration)
study of leptonic and semi-leptonic decays of heavy-light mesons.
  Results on the decay constants $f_D, f_{D_s}$ and $f_B, f_{B_s}$, the
semi-leptonic form factors of $D\longrightarrow K (K^*)$ and some preliminary
estimates of form factors relevant for the $B\longrightarrow \pi , \rho$ are
summarized. The $1/M$ corrections to asymptotic scaling laws are discussed.


title: Hadronic Molecules and Low-Energy Hadron-Hadron Scattering Amplitudes

abstract:
  Recently there has been considerable interest in the subject of molecules,
which are weakly bound states of hadron pairs. The question of the existence of
molecules is closely related to the more general problem of the determination
of low energy hadron-hadron scattering amplitudes, which is widely believed to
require nonperturbative methods. In this contribution we report on quark model
calculations using a simple perturbative scattering mechanism, one gluon
exchange followed by constituent interchange. We refer to the associated
diagrams as ``quark Born diagrams". For the cases chosen to isolate this
mechanism, I=2 $\pi\pi$, I=3/2 K$\pi$ and KN the results are usually in good
agreement with experimental S-wave scattering amplitudes given standard
potential model parameters, and for NN we find perturbative results very
similar to the nonperturbative hard cores of Oka and Yazaki. We also discuss
our findings for other less familiar channels; these include predictions of
vector-vector bound states, one of which may be the $\theta(1710)$.


title:
Bounds on the Masses and Couplings of Leptoquarks from Leptonic Partial
  Widths of the Z

abstract:
  The vertex corrections to the leptonic partial widths of the $Z$ induced by
leptoquarks that couple leptons to the top quark are considered. We obtain
stringent bounds on the parameter space of the masses and Yukawa couplings of
these leptoquarks, using the latest information on the $Z \rightarrow l^+l^-$
decay widths measured at LEP. Leptoquarks coupling with electroweak strength to
top quarks are constrained to be heavier than several hundred GeV, at 95$\%$
C.L. As a consequence, such leptoquarks cannot make a significant contribution
to lepton asymmetries, $\tau$ polarisation asymmetries or $A_{LR}$.


title: Electroweak Baryogenesis with Topological Defects

abstract:
  Electroweak baryogenesis has become a topic of much recent activity [1]. Here
we discuss a new scenario which has the advantage of being insensitive to the
order of the electroweak phase transition. We briefly review a mechanism [2]
using unstable electroweak strings [3] and discuss in detail a mechanism [4]
using topological defects (in particular cosmic strings) left behind after a
previous phase transition.


title: A Note on Spontaneous Baryogenesis

abstract:
  The original calculation of `spontaneous' baryogenesis overlooked the role
played by transport of particles onto the bubbles wall. For typical `adiabatic'
wall thicknesses and velocities one can model the problem in a fluid
approximation and the mechanism is best understood as another limit of `charge
transport' baryogenesis, and can produce a similar non-local effect in front of
the wall. (Based on a talk given at the Workshop on ELECTROWEAK PHYSICS AND THE
EARLY UNIVERSE held at Sintra, Portugal from March 22 to 27, 1994.)


title: Fermion and Sfermion Effects in $e^+ e^-$ charged Higgs pair production

abstract:
  Top and bottom one loop corrections to $e^+e^-\rightarrow H^+ H^-$ are
considered at NLC energies and found to be significantly large and negative
over the full range of $tan \, \beta$. Moreover, loop effects of moderately
heavy squarks and sleptons in the minimal supersymmetric extension of the
standard model, tend to cancel partly or fully these large corrections, thus
providing a useful indirect information about the supersymmetric sector. The
overall effect can still range between $-25 \%$ and $+25 \%$, however lies
typically around $-10 \%$ in a wide range of the model parameters.


title: Neutrino Mass and Magnetic Moment from Neutrino-Electron Scattering

abstract:
  We study both the elastic ($\nu e \rightarrow \nu e$) and the radiative
process ($\nu e \rightarrow \nu e \gamma$) and discuss how these processes can
shed light on some current topics in neutrino physics such as a neutrino
magnetic moment and neutrino oscillations. The radiative process allows to
reach low values of $Q^2$ without the need to operate at very small energies of
recoil electrons, a favourable scenario to search for a neutrino magnetic
moment. The elastic cross section contains a dynamical zero at $E_{\nu}=m/(4
sin^2\theta_{W})$ and forward electrons for the electron antineutrino channel,
which is reachable at reactor facilities and accessible after the convolution
with the antineutrino spectrum. The implication for lepton flavour changing
transitions in that energy region searched for in neutrino oscillation
experiments, which combine disappearance and appearance rates, is discussed.


title: Heavy baryons

abstract:
  We review the experimental and theoretical status of baryons containing one
heavy quark. The charm and bottom baryon states are classified and their mass
spectra are listed. The appropriate theoretical framework for the description
of heavy baryons is the Heavy Quark Effective Theory, whose general ideas and
methods are introduced and illustrated in specific examples. We present simple
covariant expressions for the spin wave functions of heavy baryons including
p--wave baryons. The covariant spin wave functions are used to determine the
Heavy Quark Symmetry structure of flavour--changing current--induced
transitions between heavy baryons as well as one--pion and one--photon
transitions between heavy baryons of the same flavour. We discuss $1/m_Q$
corrections to the current--induced transitions as well as the structure of
heavy to light baryon transitions. Whenever possible we attempt to present
numbers to compare with experiment by making use of further model--dependent
assumptions as e.g. the constituent picture for light quarks. We highlight
recent advances in the theoretical understanding of the inclusive decays of
hadrons containing one heavy quark including polarization. For exclusive
semileptonic decays we discuss rates, angular decay distributions and
polarization effects. We provide an update of the experimental and theoretical
status of lifetimes of heavy baryons and of exclusive nonleptonic two body
decays of charm baryons.


title: Intermittency and Exotic Channels

abstract:
  It is pointed out that accurate measurements of short-range two-particle
correlations in like-charge $ K\pi $ and in $ \pi^ 0\pi^ 0$ channels should be
very helpful in determining the origin of the \lq\lq intermittency\rq\rq\
phenomenon observed recently for the like-charge pion pairs.


title: Semileptonic B-Meson Decays in the Parton Model

abstract:
  We study the inclusive semileptonic B decays in the parton model. The model
gives a decay spectrum which is in excellent agreement with experiment and
makes several predictions to be tested in the forseeable future.


title:
Renormalization Group for Multiparticle Production in (2+1) Dimensions
  Around the Threshold

abstract:
  Multiparticle production in (2+1) dimensions is investigated. We show that in
a small region around the threshold the perturbation theory becomes
unapplicable due to infrared divergencies in a class of Feynman graphs with
rescattering in final state. We develop a technique based on renormalization
group for summing up leading logarithms and apply it to the $\phi^4$ models
with and without symmetry breaking and to the $O(N)$ $\phi^4$ theory.


title: $O(\alpha \alpha_s^2)$ correction to the electroweak $\rho$ parameter

abstract:
  The three-loop QCD contributions to the vacuum polarization functions of the
$Z$ and $W$ bosons at zero momentum are calculated. The top quark is considered
to be massive and the other quarks massless. Using these results, we calculate
the correction to the electroweak $\rho$ parameter. All computations are done
in the framework of dimensional regularization as well as regularization by
dimensional reduction. We use recurrence relations obtained by the method of
integration by parts to reduce all integrals to a small set of master
integrals. A comparison of the two-loop and three-loop QCD corrections to the
$\rho$ parameter is performed.


title: Patterns of quark mass matrices in a class of Calabi-Yau models

abstract:
  We study a class of superstring models compactified in the 3-generation
Calabi-Yau manifold of Tian and Yau. Our analysis includes the complete
$E_6$-singlet sector, which has been recently evaluated using techniques of
spectral and exact sequences. We use the discrete symmetries of the models to
find flat directions of symmetry breaking that leave unbroken a low energy
matter parity and make all leptoquarks heavy while preserving light Higgs
fields. Then we classify the patterns of ordinary quark mass matrices and show
that (without invoking effects due to nonrenormalizable terms) only one
structure can accommodate the observed value of fermion masses and mixing
angles, with preference for a heavy {\it top} quark ( $m_t\ge 170$ GeV for
$V_{13}\le 0.013$ ). The model, which unifies perturbatively and predicts a
realistic structure of quark mass matrices with texture zeroes, is one of the
many possible string vacua. However, in contrast with what is often assumed in
the search for realistic unified scenarios, it is highly nonminimal near the
unification scale and the predicted mass matrices have no simple symmetry
properties.


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

abstract:
  The quark-gluon plasma, formed in the first 3 fm/c of the heavy ion
collisions at RHIC and LHC, supercooles due to nucleation and develops soon a
negative pressure in the bag model. The negative pressure yields mechanical
instability which may lead to a sudden timelike deflagration to a (super)heated
hadron gas. The resulting freeze-out times are shorter than those of the
standard nucleation scenario.


title:
Using Gauge Coupling Unification and Proton Decay to Test Minimal
  Supersymmetric SU(5)

abstract:
  We derive a one-loop expression, including all thresholds, for the mass of
the proton decay mediating color triplets, $M_{D^c}$, in minimal supersymmetric
SU(5). The result for $M_{D^c}$ does not depend on other heavy thresholds or
extra representations with SU(5) invariant masses which might be added to the
minimal model. We numerically correct our result to two-loop accuracy. Choosing
inputs to maximize $M_{D^c}$ and $\tau_P$, within experimental limits on the
inputs and a $1~TeV$ naturalness bound, we derive a strict bound
$\alpha_3>0.117$. We discuss how this bound will change as experimental limits
improve. Measurements of $\alpha_3$ from deep inelastic scattering and the
charmonium spectrum are below the bound $\alpha_3>0.117$ by more than
$3\sigma$. We briefly review several ideas of how to resolve the discrepancy
between these low values of $\alpha_3$ and the determinations of $\alpha_3$
from LEP event shapes.


title: Some model-independent properties of quark mixing

abstract:
  We discuss some new invariants of quark mixing and show their usefulness with
a simple example. We also present some other new tools for analyzing quark
mixing.


title:
On the Spontaneous CP Breaking at Finite Temperature in a Nonminimal
  Supersymmetric Standard Model

abstract:
  We study the spontaneous CP breaking at finite temperature in the Higgs
sector in the Minimal Supersymmetric Standard Model with a gauge singlet. We
consider the contribution of the standard model particles and that of stops,
charginos, neutralinos, charged and neutral Higgs boson to the one-loop
effective potential. Plasma effects for all bosons are also included. Assuming
CP conservation at zero temperature, so that experimental constraints coming
from, {\it e.g.}, the electric dipole moment of the neutron are avoided, and
the electroweak phase transition to be of the first order and proceeding via
bubble nucleation, we show that spontaneous CP breaking cannot occur inside the
bubble mainly due to large effects coming from the Higgs sector. However,
spontaneous CP breaking can be present in the region of interest for the
generation of the baryon asymmetry, namely inside the bubble wall. The
important presence of very tiny explicit CP violating phases is also commented.


title: On Spontaneous Baryogenesis and Transport Phenomena

abstract:
  The spontaneous baryogenesis mechanism by Cohen, Kaplan and Nelson is
reconsidered taking into account the transport of particles inside the
electroweak bubble walls. Using linear response theory, we calculate the
modifications on the thermal averages of the charges of the system due to the
presence of a space time dependent `charge potential' for a quantum number not
orthogonal to baryon number. The local equilibrium configuration is discussed,
showing that, as a consequence of non zero densities for conserved charges, the
$B+L$ density is driven to non zero values by sphaleronic processes. Solving a
rate equation for the baryon number generation, we obtain an expression for the
final baryon asymmetry of the Universe containing the relevant parameters of
the bubble wall, {\it i.e.} its velocity, its width, and the width of the
region in which sphalerons are active. Compared to previous estimates in which
transport effects were not taken into account, we find an enhancement of nearly
three orders of magnitude in the baryon asymmetry. Finally, the role of QCD
sphalerons in cooperation with transport effects is analyzed, showing that the
net result depends crucially on the particle species which enter into the
charge potential.


title: Jets in Photon-Photon Collisions

abstract:
  We study jet production in photon-photon reactions at the next-to-leading
logarithm accuracy. The discussion of the theoretical uncertainties and the
role of the quark and gluon distributions in the photon is emphasized. The
phenomenology at TRISTAN energies is discussed and predictions are made for LEP
200.


title: A Model for the Three Lepton Decay Mode of the Proton

abstract:
  An extension of the left--right symmetric model has been constructed which
gives in a natural way the three lepton decay modes of the proton which have
been suggested as an explanation for the atmospheric neutrino anomaly. We write
down the potential which after minimization gives the proper choice of the
Higgs spectrum. With this Higgs spectrum we then study the evolution of the
gauge coupling constants and point out that for consistency one has to include
effects of gravity.


title: Boron neutrino flux and the MSW solution of the solar neutrino problem

abstract:
  There are large uncertainties in the predictions of the boron neutrino flux
from the Sun which cannot be considered as being of purely statistical origin.
We treat the magnitude of this flux, $\Phi_B$, as a parameter to be found from
experiment. The properties of the MSW solution to the solar neutrino problem
for different values of $\Phi_B$ are studied. Present data give the bounds:
$0.38 < \Phi_B/ \Phi_B^0 < 3.1$ (2$\sigma$), where $\Phi_B^0 \equiv 5.7 \cdot
10^6$ cm$^{-2}$s$^{-1}$ is the flux in the reference SSM. The variations of the
flux in this interval enlarge the allowed region of mixing angles: $\sin^2
2\theta = 8\cdot 10^{-4} \div 2\cdot 10^{-2}$ (small mixing solutions) and
$\sin^2 2\theta = 0.2 \div 0.85$ (large mixing solution). If the value of the
original boron neutrino flux is about that measured by Kamiokande, a consistent
description of the data is achieved for $\sin^2 2\theta \sim (0.8 \div 2)\cdot
10^{-3}$ (``very small mixing solution"). The solution is characterized by a
strong suppression of the beryllium neutrino line, a weak distortion of the
high energy part of the boron neutrino spectrum and a value of the double ratio
$(CC/NC)^{exp}/(CC/NC)^{SSM}$ at $E > 5$ MeV close to 1. We comment on the
possibility to measure the neutrino parameters and the original boron neutrino
flux in future experiments.


title: Extended Nambu-Jona-Lasinio Model vs QCD Sum Rules

abstract:
  We argue that the extended Nambu-Jona-Lasinio model of hadrons can be be
probed and constrained in a nontrivial way via QCD sum rules. While there arise
rather restrictive bounds on the strength of the effective four-fermion
interaction in the vector channel, introduction of the four-fermion interaction
in the pseudoscalar channel could resolve a long standing puzzle of QCD sum
rules. We speculate also on possible connection between effective four-quark
interactions describing the low-energy phenomenology and ultraviolet
renormalons of the fundamental QCD.


title:
Tevatron and LEP-II Probes of Minimal and String-Motivated Supergravity
  Models

abstract:
  We explore the ability of the Tevatron to probe Minimal Supersymmetry with
high energy scale boundary conditions motivated by supersymmetry breaking in
the context of supergravity/superstring theory. A number of boundary condition
possibilities are considered: dilaton-like string boundary conditions applied
at the standard GUT unification scale or alternatively at the string scale; and
extreme (``no-scale'') minimal supergravity boundary conditions imposed at the
GUT scale or string scale. For numerous specific cases within each scenario the
sparticle spectra are computed and then fed into ISAJET 7.07 so that explicit
signatures can be examined in detail. We find that, for some of the boundary
condition choices, large regions of parameter space can be explored via
same-sign dilepton and isolated trilepton signals. For other choices, the mass
reach of Tevatron collider experiments is much more limited. We also compare
mass reach of Tevatron experiments with the corresponding reach at LEP 200.


title: Vector-like Strong Coupling theory with small S and T parameters

abstract:
  We propose a mechanism which can reduce the Peskin and Takeuchi's S, T and U
parameters in dynamical electroweak symmetry breaking models. It is interesting
that not only S but also T parameter can become small even if there exists
large isospin violation in fermion condensation. For example, when we take the
$SU(2)_L\times U(1)_Y$ breaking mass of up-type fermion $m_U=1$ TeV and that of
down-type $m_D=0$, we get S$\sim 0.001 N$ and T$\sim 0.05 N$ for the
$SU(2)_L\times U(1)_Y$ invariant masses $M=10$ TeV. The point is that these
parameters are suppressed by $SU(2)_L\times U(1)_Y$ invariant masses which the
vector-like fermions can have.


title: Sensitivity Of Dark Matter Dectectors To Susy Dark Matter

abstract:
  The sensitivity of dark matter detectors to the lightest neutralino (${\tilde
{Z}_1}$) is considered within the framework of supergravity grand unification
with radiative breaking of SU(2)xU(1). The relic density of the ${\tilde
{Z}_1}$ is constrained to obey $0.10 \leq \Omega_{\tilde {Z}_1}h^2 \leq 0.35$,
consistent with COBE data and current measurements of the Hubble constant.
Detectors can be divided into two classes: those most sensitive to spin
dependent incoherent scattering of the ${\tilde {Z}_1}$ (e.g. $CaF_2$) and
those most sensitive to spin independent coherent scattering (high A nuclei
e.g. Pb). The parameter space is studied over the range of $100GeV \leq m_0,
m_{\tilde {g}} \leq 1 TeV; 2 \leq tan\beta \leq 20$; and $-2 \leq A_t/m_0 \leq
3$ and it is found that the latter type detector is generally more sensitive
than the former type. Thus at a sensitivity level of $R \geq 0.1$ events/kg da,
a lead detector could scan roughtly 30% of the ~parameter space studied, and an
increase of ~this sensitivity by a factor of 10 ~would lead to coverage of
about 70% of the parameter space. Dark matter detectors are in general more
sensitive to the high $tan\beta$, low $m_{\tilde {g}}$ and low m_0 parts of the
parameter space. The conditions of radiative breaking of SU(2)xU(1) enter
importantly in analysing the efficiency of dark matter detectors.


title:
Role of Scalar Meson Resonances in $K_{L}^{0} \rightarrow \pi^{0} \gamma
  \gamma Decay

abstract:
  Corrections to $K_{L}^{0}\rightarrow \pi^{0} \gamma \gamma$ decay induced by
scalar meson exchange are studied within chiral perturbation theory. In spite
of bad knowledge of scalar-mesons parameters, the calculated branching ratio
can be changed by a few percent.


title:
On the Role of the Higgs Mechanism in Present Electroweak Precision
  Tests

abstract:
  Based on the observables $\MW$, $\Gamma_l$, $\bar\sw^2(\MZ^2)$, we evaluate
the parameters $\Delta x, \Delta y$ and $\varepsilon$ at one-loop level within
an electroweak massive vector-boson theory, which does not employ the Higgs
mechanism. The theoretical results are consistent with the experimental ones on
$\Delta x$, $\Delta y$, $\varepsilon$. The theoretical prediction for $\Delta
y$ coincides with the standard-model one (apart from numerically irrelevant
terms which vanish for $\MH\to\infty$). Non-renormalizability only affects
$\Delta x$ and $\varepsilon$, which differ from the standard-model results by
the replacement $\log\MH\to\log\Lambda$ for a heavy Higgs mass, $\MH$ (where
$\Lambda$ denotes an effective UV cut-off).


title: Characteristics of Cosmic String Scaling Configurations

abstract:
  Using the formalism developed in a previous paper we analyze the cosmological
implications of our conclusions concerning the scaling behaviour of a network
of cosmic strings, in particular the idea that once gravitational back-reaction
becomes important the transient scaling regime so far explored by numerical
simulations will be replaced by a new `full scaling' regime, with slightly
different parameters. This has consequences for the normalization of the string
tension on all scales. We show how the new scaling solutions affect the
gravitational wave bound from nucleosynthesis and the milli-second pulsar, and
also describe the consequences from large scale structure up to COBE scales.


title: Scale Anomaly Induced Instanton Interaction

abstract:
  The binary interaction of large size instantons in a SU(2) Yang-Mills theory
is obtained from the one-loop effective action for the field strength. The
instanton interaction is calculated as a function of the instanton separation
and in dependence on radius and relative orientation of the instantons. Two
equally oriented instantons with radii large compared with the scale defined by
the gluon condensate have purely attractive interaction, whereas the
interaction of maximal disoriented instantons is repulsive. We argue that the
medium range attractive interaction of the instantons generally holds and is
solely due to the instability of the perturbative vacuum.


title: W and Z Polarization Effects in Hadronic Collisions

abstract:
  A Monte Carlo study of the polar and azimuthal angular distributions of the
lepton pair arising from the decay of a $W$ or $Z$ boson produced at high
transverse momentum in hadronic collisions is presented. In the absence of cuts
on the final state leptons, the lepton angular distribution in the gauge boson
rest frame is determined by the gauge boson polarization. Numerical results for
the lepton angular distributions in the Collins--Soper frame with acceptance
cuts and energy resolution smearing applied to the leptons are presented. In
the presence of cuts, the lepton angular distributions are dominated by
kinematic effects rather than polarization effects, however, some polarization
effects are still observable on top of the kinematic effects. Polarization
effects are highlighted when the experimental distributions are divided by the
Monte Carlo distributions obtained using isotropic gauge boson decay.


title: Parton Distributions in the Photon

abstract:
  We discuss in detail the photon structure function beyond the leading
logarithm approximation. Of special concern is the factorization scheme and the
hadronic input; we show how to naturally absorb large terms due to the MSbar
factorization scheme in a modified hadronic component. The effect of the charm
quark mass threshold is also discussed in relation to the phenomenology. A
comparison with data shows that the modified hadronic component can be
reasonably described by a VDM-type input.


title: On Hyperfine Splittings of Strange Baryons in the Skyrme Model

abstract:
  We calculate the complete order $1/N$ corrections to baryon masses in the
rigid rotator approach to the 3-flavor Skyrme model.


title: Electromagnetic Nucleon Properties and Quark Sea Polarization

abstract:
  In this paper we present the derivation as well as the numerical results for
all electromagnetic form factors of the nucleon within the chiral quark soliton
model in the semiclassical quantization scheme. The model is based on a
semibosonized Nambu -- Jona-Lasinio lagrangean where the boson fields are
treated as classical ones. Other observables, namely the nucleon mean squared
radii, the magnetic moments and the nucleon--$\Delta$ splitting are calculated
as well. The calculations have been done taking into account the quark sea
polarization effects. The final results, including rotational $1/N_c$
corrections, are compared with the existing experimental data and they are
found to be in a good agreement for the constituent quark mass of $400-420$
MeV.


title: A Direct Test of Perturbative QCD at Small x

abstract:
  We show that recent data from HERA on the proton structure function $F_2$ at
small $x$ and large $Q^2$ provide a direct confirmation of the double
asymptotic scaling prediction of perturbative QCD. A linear rise of $\ln F_2$
with the scaling variable $\sigma$ is observed throughout the kinematic region
probed at HERA, and the measured slope is in excellent agreement with the QCD
prediction. This provides a direct determination of the leading coefficient of
the beta function. At large values of the scaling variable $\rho$ the data
display a small but statistically significant scaling violation.


title: Fragmentation contribution to quarkonium production in hadron collision

abstract:
  We compute the contributions due to gluon and heavy-quark fragmentation to
quarkonium production at large transverse momentum in $\bar p p$ and $p p$
collisions. For inclusive $J/\psi$ production, there is a large contribution
from the $g \rightarrow \chi_c$ fragmentation. At large $p_T$, this is
comparable to the conventional charmonium model prediction via gluon fusion at
the ISR and dominates over the latter at the Tevatron energy. This may help to
explain, at least partly, the large $J/\psi$ production cross-section recently
observed by the CDF experiment. However, the fragmentation contribution to
$\psi^{\prime}$ production is not large enough to explain the corresponding CDF
data. We also present the results for $\Upsilon$ production at ISR and Tevatron
energies.


title: Note Added to ``Baryon Asymmetry of the Universe in the Standard Model"

abstract:
  Recent papers by Gavela et al. and Huet et al. claim to have shown that
incluion of higher order interactions between quasiparticles dramatically
decreases the baryon asymmetry of the universe which can arise in the Minimal
Standard Model. These papers employ an inconsistent calculational scheme which,
for instance, violates unitarity. We argue that their method cannot be
considered as reliable, and thus their conclusions cannot be considered as
justified.


title: String-Organized Field Theory

abstract:
  A low energy string theory should reduce to an ordinary quantum field theory,
but in reality the structures of the two are so different as to make the
equivalence obscure. The string formalism is more symmetrical between the
spacetime and the internal degrees of freedom, thus resulting in considerable
simplification in practical calculations and novel insights in theoretical
understandings. We review here how tree or multiloop field-theoretical diagrams
can be organized in a string-like manner to take advantage of this
computational and conceptual simplicity.


title:
$b \rightarrow s\gamma$ Decay in Supergravity Grand Unification and Dark
  Matter

abstract:
  An analysis of the $b \rightarrow s\gamma$ is given in supergravity grand
unification using the framework of the radiative breaking of the electro-weak
symmetry under three separate sets of constraints:1) neutralino relic density
does not overclose the universe,2)p-stability constraint, and 3) the combined
constraints of p-stability and COBE data .For case 1 it is found that the CLEO
II data on the branching ratio already imposes very strong further constraints
on dark matter analyses. For case2 the branching ratio is found to lie in the
range (1.5-6.3)x$10^{-4}$ and thus the data does not at present significantly
limit the analyses with p-stability constraint. It is shown that improvements
by a factor of 3 in the $p \rightarrow\bar\nu K^{+}$ lifetime will reduce SUSY
effects to less than O(30$\%$) of the Standard Model value.For case3,the
branching ratio lies in the interval (3.1-5.3)x$10^{-4}$, and the SUSY effects
lie within (-10$\%$,+50$\%$) of the SM value. Thus as experimental bounds on
$B(b \rightarrow s\gamma)$ improve, one would need in cases 2 and 3 the
next-to-leading order QCD corrections to disentangle SUSY effects.


title:
Implications for Supersymmetric Dark Matter Detection from Radiative $b$
  Decays

abstract:
  We point out that combinations of parameters that predict large counting
rates in experiments searching for supersymmetric dark matter often tend to
predict a very large branching ratio for the inclusive decay \bsg. The recent
measurement of this branching ratio, therefore, indicates that searches for
supersymmetric dark matter might be even more difficult than previously
anticipated.


title: CP Violation in $B^\pm\to \gamma\pi^\pm\pi^+\pi^-$

abstract:
  We consider CP violating effects in decays of the type $B^\pm\to \gamma
a^\pm_{1,2}$ where $a_{1,2}$ are the $J^P=1^+$ and $2^+$ resonances each
decaying to the common final state via $a^\pm_{1,2} \to\pi^\pm\rho^0$. The
resonances enhance the CP asymmetries and also knowledge of their masses and
widths facilitates calculations of the effects. Several types of CP asymmetries
are sizable ($\sim10$--30\%) requiring about (3--10)${}\times10^8$ $B^\pm$
mesons for detection at the $3\sigma$ level thereby providing a method for
measuring the angle $\alpha$ in the unitarity triangle. \bigskip


title: Power Suppressed Corrections to Hadronic Event Shape Variables

abstract:
  For high energy processes ($M\gg \Lambda_{QCD}$) there are infrared safe
hadronic shape variables that have a calculable perturbative expansion in
$\alpha_s(M^2)$. However, nonperturbative power suppressed corrections to these
variables are not well understood. We use the behavior of large orders of the
perturbation expansion to gain insight into the nonperturbative corrections.
Our results suggest that certain shape variables have nonperturbative
corrections suppressed by fractional powers of $\Lambda_{QCD}^2/M^2$.


title:
Exclusive and Semi-Inclusive B Decays Based on \hspace{0.3cm} b
  $\rightarrow$ s \hspace{0.01cm}$\eta_c$ \hspace{0.3cm} Transition

abstract:
  We calculate the semi-inclusive processes B $\rightarrow X_{s} \eta_c$ and
relate it to B $\rightarrow X_{s} \psi$ in next to leading order QCD, and show
how it can be used to determine an accurate value of $f_{\eta_{c}}$. The
exclusive modes B $\rightarrow$ K$\eta_c$ and B $\rightarrow$ K$\psi$ also
yield similar results, whereas B $\rightarrow$ K$^*\eta_c$ and B $\rightarrow$
K$^*\psi$ can provide valuable information on hadronic form factors. We also
estimate the branching ratios and the ratios of exclusive to inclusive decay
modes dominated by $b \rightarrow s\e$.


title:
Evidence for Gluon Energy Loss as the Mechanism for Heavy Quarkonium
  Suppression in $pA$ Collisions

abstract:
  We study the energy and nuclear A dependence of the hadronic production of
heavy quarkonia. We review theoretical ideas which have been put forward,
seeking a consistent global picture reconciling the large effects in quarkonia
with the small nuclear effects observed in continuum Drell Yan production. The
data indicates that shadowing or leading twist modifications of parton
distributions can be ruled out as explanations, leaving higher twist energy
loss. {}From general principles the maximum allowed energy loss of partons
traversing the nuclear medium can be related to the parton transverse momenta.
We then show that the experimental data on nuclear suppression of charm- and
bottom- onium for large $x_F$ is consistent with this effect: using the
observed transverse momenta to bound the $x_F$ dependence in an almost model
independent manner generates a relation that practically reproduces the data.
Several prediction are discussed; the dependence on $x_F$ as $x_F\to 1$, and
large and small $k_T^2$ cuts, can be used to discriminate between quark and
gluon induced effects.


title:
Four Weak Boson Production in Tev Photon--Photon Collisions and Heavy
  Higgs Signal

abstract:
  We study the signals for a heavy Higgs boson in the processes
$\gamma\gamma\to WWWW$, $\gamma\gamma\to WWZZ$ at the photon linear collider.
The results are based on the first complete tree level calculation for these
reactions. Using a forward ``spectator" $W$ tag, central ``spectator" $W$ veto
to suppress backgrounds from transverse $W$, $Z$ production we show that the
invariant mass spectrum of central $WW$, $ZZ$ pairs is sensitive to Higgs boson
with a mass up to 1~TeV at a 2~TeV linear collider.


title:
Treating Solar Model Uncertainties: A Consistent Statistical Analysis of
  Solar Neutrino Models and Data

abstract:
  We describe how to consistently incorporate solar model uncertainties, along
with experimental errors and correlations, when analyzing solar neutrino data
to derive confidence limits on parameter space for proposed solutions of the
solar neutrino problem. Our work resolves ambiguities and inconsistencies in
the previous literature. As an application of our methods we calculate the
masses and mixing angles allowed by the current data for the proposed MSW
solution using both Bayesian and frequentist methods, allowing purely for solar
model flux variations, to compare with previous work. We consider the effects
of including metal diffusion in the solar models and also discuss implications
for future experiments.


title: Upper bound on Hot Dark Matter Density from $SO(10)$ Yukawa Unification

abstract:
  We study low-energy consequences of supersymmetric $SO(10)$ models with
Yukawa unification $h_t = h_N$ and $h_b = h_\tau$. We find that it is difficult
to reproduce the observed $m_b/m_\tau$ ratio when the third-generation
right-handed neutrino is at an intermediate scale, especially for small $\tan
\beta$. We obtain a conservative lower bound on the mass of the right-handed
neutrino $M_N > 6 \times 10^{13}$~GeV for $\tan \beta < 10$. This bound
translates into an upper bound on the $\tau$-neutrino mass, and therefore on
its contribution to the hot dark matter density of the present universe,
$\Omega_\nu h^2 < 0.004$. Our analysis is based on the full two-loop
renormalization group equations with one-loop threshold effects. However, we
also point out that physics above the GUT-scale could modify the Yukawa
unification condition $h_b = h_\tau$ for $\tan \beta \lsim 10$. This might
affect the prediction of $m_b/m_\tau$ and the constraint on $M_N$.


title:
The Search for the Decay of Z Boson into Two Gammas as a Test of Bose
  Statistics

abstract:
  We suggest that Bose statistics for photons can be tested by looking for
decays of spin-1 bosons into two photons. The experimental upper limit on the
decay $Z \rightarrow \gamma \gamma $ is used to establish for the first time
the quantitative measure of the validity of Bose symmetry for photons.


title: Nambu-Jona-Lasinio Model vs QCD

abstract:
  We argue that the extended Nambu-Jona-Lasinio model which introduces
four-quark interactions to describe hadron physics at low energies can be
confronted with fundamental quantum chromodynamics by means of spectral sum
rules. While there arise rather restrictive bounds on the strength of the
effective four-quark interaction in the vector channel, introduction of the
four-quark interaction in the pseudoscalar channel resolves a long standing
puzzle of the sum rules.


title:
Green functions from a gauge-invariant effective action for the
  electroweak Standard Model

abstract:
  Application of the background-field method to the electroweak Standard-Model
yields a gauge-invariant effective action giving rise to simple Ward
identities. We find that in the background-field `t Hooft-Feynman gauge the
resulting vertex functions are exactly those that are obtained using the pinch
technique. Thus, the background-field method provides a general framework that
generalizes the pinch technique directly and uniquely to arbitrary Green
functions and arbitrary orders of perturbation theory. Moreover, the desirable
properties of the pinch-technique vertex functions hold for arbitrary gauge
parameters and have a simple explanation within the background- field method.


title: Dynamical Electroweak Symmetry Breaking

abstract:
  We review the status of and recent developments in dynamical electroweak
symmetry breaking, concentrating on the ideas of technicolour and top quark
condensates. The emphasis is on the essential physical ideas and experimental
implications rather than on detailed mathematical formalism.


title: QCD S Parameter from Inhomogeneous Bethe-Salpeter Equation

abstract:
  We calculate the low-energy parameter S in QCD, which is also known as
L_{10}, and the pion decay constant f_\pi using inhomogeneous Bethe-Salpeter
equation in improved ladder approximation. To extract these quantities we
calculate the ``V-A'' two-point function, \Pi_{VV}(q^2) - \Pi_{AA}(q^2), in
space-like region. We obtain S = 0.43 \sim 0.48, which is about 30% larger than
the experimental value. The calculated f_\pi is well consistent with the result
by solving the homogeneous Bethe-Salpeter equation for pion. We also evaluate
$S$ parameter in SU(3) gauge theory with N_D doublets of fermions in connection
with walking technicolor model, and find that the value of S/N_D hardly depends
on N_D.


title: Susy Particles

abstract:
  Analysis of the SUSY spectrum in supergravity unified models is given under
the naturalness criterion that the universal scalar mass $(m_0)$ and the gluino
mass $(m_{\tilde g})$ satisfy the constraint $m_0, m_{\tilde g}$ less than or
equal to 1 TeV. The SUSY spectrum is analysed in four different scenarios: (1)
minimal supergravity models ignoring proton decay from dimension five
operators, (2) imposing proton stability constraint in supergravity models with
SU(5) type embedding which allow proton decay via dimension five operators, (3)
with inclusion of dark matter constraints in models of type (1), and (4) with
inclusion of dark matter constraint in models of type (2). It is found that
there is a very strong upper limit on the light chargino mass in models of type
(4), i.e., the light chargino mass is less than or equals 120 GeV.


title: Calculation of two-loop self-energies in the electroweak Standard Model

abstract:
  Motivated by the results of the electroweak precision experiments, studies of
two-loop self-energy Feynman diagrams are performed. An algebraic method for
the reduction of all two-loop self-energies to a set of standard scalar
integrals is presented. The gauge dependence of the self-energies is discussed
and an extension of the pinch technique to the two-loop level is worked out. It
is shown to yield a special case of the background-field method which provides
a general framework for deriving Green functions with desirable theoretical
properties. The massive scalar integrals of self-energy type are expressed in
terms of generalized multivariable hypergeometric functions. The imaginary
parts of these integrals yield complete elliptic integrals. Finally,
one-dimensional integral representations with elementary integrands are derived
which are well suited for numerical evaluation.


title: Searching for the Higgs Boson(s)

abstract:
  The ability of LEP-200, the Tevatron, the Di-Tevatron, the LHC, and a next
linear $\epem$ collider (NLC) to probe the Higgs sectors of the minimal
Standard Model (SM) and the Minimal Supersymmetric Model (MSSM) is reviewed.
Emphasis is placed on newly developed detection modes and on predictions for
supersymmetric particle Higgs decay channels when the MSSM is constrained using
boundary conditions motivated by supergravity/superstring models.


title:
Solvability, Consistency and the Renormalization Group in Large-$N_c$
  Models of Hadrons

abstract:
  We establish the following fundamentals about Lagrangian models of
meson-baryon interactions in the large-$N_{c}$ limit: 1. Calculating the
leading-order contribution to $1$-meson/$2$-baryon Green's functions in the
$1/N_c$ expansion involves summing an infinite class of divergent Feynman
diagrams. So long as the bare Lagrangian properly obeys all large-$N_c$
selection rules, this all-loops resummation is accomplished exactly by solving
coupled classical field equations with a short-distance cutoff. 2. The only
effect of the resummation is to renormalize the bare Yukawa couplings, baryon
masses and hyperfine baryon mass splittings of the model. 3. In the process,
the large-$N_{c}$ renormalization group flow of these bare parameters is
completely determined. We conjecture that variants of the Skyrme model emerge
as UV fixed points of such flows.


title:
Top Quark Contribution to Hadronic Decays of the Z-Boson at Alpha_s^2 in
  QCD

abstract:
  We evaluate the effect of a virtual top quark on the coefficient of
$\alpha_{s}^{2}$ in the decay rates $\Gamma(Z \rightarrow {\rm hadrons})$ and
$\Gamma(Z \rightarrow b\overline{b} )$. We treat the dependence on the top
quark mass exactly instead of using a large mass expansion. The present work
completes the evaluation of the $\alpha_{s}^{2}$ contributions to these
quantities. The calculation uses both the $\overline{\rm MS}$ and
Collins-Wilczek-Zee renormalization prescriptions. The results can be applied
to the hadronic decays of the $\tau$-lepton.


title: Remarks on Koba-Nielsen-Olesen Scaling

abstract:
  It is shown that there is a second properly normalized KNO scaling function,
$nP_n(n/\bar n)=\varphi(z)$, which has certain advantages in the analysis of
KNO scaling. First, the $nP_n$ are not influenced by the statistical and
systematic uncertainties of $\bar n$ hence $\varphi(z)$ provides more selective
power than the original KNO scaling function $\bar nP_n(n/\bar n)=\psi(z)$.
Second, the new scaling function generates scale parameter $\sigma=1$ since it
depends only on the combination of $z$ and the scale parameter of $\psi(z)$. An
analysis of $\varphi(z)$ is given using $e^+e^-$ annihilation data for charged
particle multiplicity distributions.


title: Inflatonless inflation

abstract:
  Whichever could be the real theory of gravitation, the corresponding
low-energy effective lagrangian will probably contain higher derivative terms.
In this work we study the general conditions on those terms in order to produce
enough inflation to solve some of the problems of the standard
  Friedmann-Robertson-Walker cosmology in absence of any inflaton field. We
apply our results to some particular scenarios where higher derivative terms
appear in the effective lagrangian for gravity like those coming from graviton
(two)-loops or integrating out ordinary matter (like the one present in the
Standard Model).


title: Towards a unified theory of mesons and baryons

abstract:
  In this review we report on advances in topological soliton models of the
nucleon. In chapter I we construct an effective lagrangian of QCD with the low
mass mesons ($\pi,\rho,A_1$ and the scalar meson $\epsilon$) generalising the
Skyrme model. The vector meson fields are introduced as massive gauge fields in
the linear sigma model and we look for topological soliton solutions of the
model. The results for the nucleon-nucleon interaction show that the scalar
degrees of freedom give rise to attractive intermediate range forces. This is
in sharp contrast to models incorporating vector degrees of freedom where only
repulsive forces are found. In chapter II we evaluate the leading correction to
the classical Skyrmion mass. The main ultraviolet divergence is cancelled by
well known chiral counterterms. The low energy behaviour of the phase shifts
which are large and positive dominates the result. As a consequence, the
correction is found to be negative and rather large, of the order of 1 GeV for
the original Skyrme model. We then show that the situation improves if one
introduces higher chiral orders in the effective lagrangian. The problem of the
stability of topological solitons when vector fields enter the chiral


title: Top Quark Physics

abstract:
  Top quark studies at future $e^+e^-$ colliders are considered. Two issues are
discussed: {a --}Some results are presented on the decays of top quarks. Energy
distributions of charged leptons and neutrinos in $t\to bW\to be^+\nu$ and jets
in $t\to bW\to b\bar du$ decays are sensitive to the structure of $tbW$ vertex.
Distributions of charged leptons from top decays are particularly useful in
polarization studies whereas neutrinos are sensitive to deviations from the
Standard Model. {b --}Recent calculations are reviewed on the top quark pair
production in $e^+e^-$ annihilation. The differential cross sections in the
threshold region can lead to an accurate determination of the top quark mass
and the interquark potential. The effects of the top-Higgs Yukawa coupling and
some higher order QCD corrections are also under control.


title: CP Violation in the B System: What's Old, What's New?

abstract:
  I review the many ways of obtaining information about the CKM matrix through
CP violation in the $B$ system. I include direct and indirect CP violation, the
role of penguins and isospin analysis, tagging, and $B\to DK$ decays. I also
discuss recent developments showing how to use $SU(3)$ flavor symmetry, along
with some dynamical approximations, to extract from $B$ decays to $\pi\pi$,
$\pi K$ and $K\kbar$ the weak CKM phases, the strong phase shifts, and the
sizes of the various contributing diagrams. Finally, I briefly show what can be
learned from an exact treatment of the CKM matrix. (Talk given at the 5th
Conference on the Intersections of Particle and Nuclear Physics, St.
Petersburg, Florida, USA, May 31-June 6, 1994.)


title: Strong WW Scattering at Photon Linear Colliders

abstract:
  We investigate the possibility of observing strong interactions of
longitudinally polarized weak vector bosons in the process $\gamma \gamma \to
ZZ$ at a photon linear collider. We make use of polarization of the photon
beams and cuts on the decay products of the $Z$ bosons to enhance the signal
relative to the background of transversely polarized $ZZ$ pairs. We find that
the background overwhelms the signal unless there are strong resonant effects,
as for instance from a technicolor analogue of the hadronic $f_2(1270)$ meson.


title: Minijets in gamma p and gamma gamma collisions

abstract:
  I discuss the minijet contribution to total photoproduction and
photon--photon cross sections. While minijets with $p_T$ around 2 GeV have
recently been observed directly in \gamgam\ experiments, the total \gamp\ cross
section measured at HERA is in excellent agreement with predictions based on
purely soft physics. Due to the large number of free parameters, predictions
for the minijet contribution to total cross sections can be brought into
agreement with these seemingly paradoxical observations. However, the currently
used eikonalization procedure may not be applicable at all to a large part of
the minijet contribution, making it very difficult to draw definite conclusions
at present.


title:
Solution of the Strong CP problem in the low energy effective Standard
  Model

abstract:
  We consider the low energy effective chiral theory of QCD mesons and the
electroweak Goldstone bosons. In this effective theory the pion sector
contributes to the gauge boson masses and the Yukawa couplings of the fermions.
Consequently the Yukawa sector of quarks and leptons can have a $SU(2)_L\times
U(1)_Y\times U(1)_A$ global symmetry even with nonvanishing fermion masses. The
extra chiral $U(1)_A$ symmetry can be used to rotate the CP violating $\bar
\theta G\tilde G $ term away which therefore makes no contribution to low
energy CP violating effects like the neutron electric dipole momment. The
Goldstone mode associated with this $U(1)_A$ symmetry may be identified with
the $SU(2)$ singlet meson $\eta_0$.


title:
The Electroweak Chiral Lagrangian and CP-Violating Effects in
  Technicolor Theories

abstract:
  We estimate the CP-violating $WW\gamma$ and $WWZ$ anomalous form factors,
arising from CP-violating interactions in extended technicolor theories, and
discuss their future experimental detectability. The electric dipole moment of
the $W$ boson is found to be as large as ${\cal O}(10^{-21}) \; \mbox{$e$ cm}$.
We connect the CP-odd $WW\gamma$ and $WWZ$ couplings to the corresponding
CP-violating electroweak chiral lagrangian operators. The electric dipole
moments of the neutron and the electron in technicolor theories are estimated
to be as large as ${\cal O}(10^{-26}) \; \mbox{$e$ cm}$ and ${\cal O}(10^{-29})
\; \mbox{$e$ cm}$ respectively. We also suggest the potential to observe large
CP-violating technicolor effects in the decay $t \rightarrow b + W^+$.


title:
Suppression of Proton Decay in the Missing-Partner Model for
  Supersymmetric SU(5) GUT

abstract:
  We construct a missing-partner model for supersymmetric SU(5) GUT assuming
the Peccei-Quinn symmetry, in which the SU(5) gauge coupling constant remains
in the perturbative regime below the gravitational scale $\sim2.4\times
10^{18}\GEV$. The Peccei-Quinn symmetry suppresses the dangerous dimension-five
operators for the nucleon decay much below the limit from the present
proton-decay experiments. We also stress that due to this suppression mechanism
our model can accommodate even the large $\tan\beta_H$ ($\sim$ 60) scenario
which has been recently suggested to explain the observed value of the
$m_b/m_\tau$ ratio.


title:
Triangles, Triangles, Triangles: CP Violation in the B System and the
  Measurement of Strong and Weak Phases

abstract:
  We present the current wisdom regarding the measurement of the CP-violating
phases of the CKM unitarity triangle in $B$-meson decays. After an introduction
to the SM picture of CP violation, we review direct and indirect CP violation,
the role of penguins and isospin analysis, and $B\to DK$ decays. We also
discuss recent work on how to use SU(3) flavor symmetry, along with some
dynamical approximations, to get at the CKM weak phases. Through
time-independent $B$-decay measurements alone, we show that it is possible to
extract all information: the weak phases, the incalculable strong phase shifts,
and the sizes of the tree, color-suppressed, and penguin contributions to these
decays.


title:
Bounds on the Ratio of Higgs Vacuum Expectation Values in the Minimal
  Supersymmetric Standard Model from the Top and Bottom Quark Masses

abstract:
  The top quark mass values from the CDF Collaboration and the precision
electroweak data at LEP combined with the bottom mass value allow to establish
bounds on the parameter tan beta in the minimal supersymmetric standard model
(MSSM) independent of the soft supersymmetry breaking parameters. We find: 0.96
< tan beta < 52.2 at the 95 % C.L., which is mostly the region tan beta >1,
where radiative electroweak symmetry breaking is possible. Assuming electroweak
symmetry breaking leads to: tan beta=1.2 +- 0.2, if one neglects the high tan
beta solution, which is unlikely due to proton lifetime limits.


title:
Topologically non--trivial chiral transformations: The chiral invariant
  elimination of the axial vector meson

abstract:
  The role of chiral transformations in effective theories modeling Quantum
Chromo Dynamics is reviewed. In the context of the Nambu--Jona--Lasinio model
the hidden gauge and massive Yang--Mills approaches to vector mesons are
demonstrated to be linked by a special chiral transformation which removes the
chiral field from the scalar--pseudoscalar sector. The chirally rotated axial
vector meson field ($\tilde A_\mu$) transforms homogeneously under flavor
rotations and may thus be dropped without violating chiral symmetry. The
fermion determinant for static meson field configurations is computed by
summing the discretized eigenvalues of the Dirac Hamiltonian. It is discussed
how the local chiral transformation loses its unitary character in a finite
model space. This technical issue proves to be crucial for the construction of
the soliton within the Nambu--Jona--Lasinio model when the chirally rotated
axial vector field is neglected. In the background of this soliton the valence
quark is strongly bound, and its eigenenergy turns out to be negative. This
important physical property which is usually generated only by non--vanishing
axial vector is thus carried over by the simplification $\tilde A_\mu=0$.


title:
Branching ratio and direct CP-violating rate asymmetry of the rare
  decays $B \to K^\ast \gamma$ and $B \to \rho \gamma$

abstract:
  We calculate CP-violating rate asymmetries in the rare radiative decays
$B^\pm\rightarrow K^{\ast\pm} \gamma$ and $B^\pm\rightarrow \rho^\pm \gamma$.
They arise because of the interference between leading-order penguin amplitudes
and one-gluon corrections with absorptive phases, and provide unambiguous
evidence for direct CP violation. Complementing earlier studies, we also
investigate gluon exchange with the `spectator' quark. The bound state effects
in the exclusive matrix elements are taken into account by a covariant model,
which yields a branching ratio $BR(B\rightarrow K^\ast \gamma) = (4-5)\times
10^{-5}$ in good agreement with the observed value. The bound state effects
increase the CP asymmetry, which is of order $1 \%$ in the channel
$B\rightarrow K^\ast \gamma$ and $15 \%$ for $B \to \rho \gamma$.


title: Thermal Activation Rates in the Chirally Asymmetric Gross-Neveu Model

abstract:
  We address the problem of how to incorporate quantum effects into the
calculation of finite-temperature decay rates for a metastable state of a
quantum field theory. To do this, we consider the Gross-Neveu model with an
explicit chiral symmetry breaking term, which allows for a metastable state.
This theory can be shown to have a "critical bubble" which is a solution to the
*exact* equations of motions (i.e. to all orders in perturbation theory,
including all higher derivative, quantum and thermal corrections). This
configuration mediates the thermal activation of the metastable vacuum to the
true ground state, with a decay rate $\Gamma \propto \exp(-F_c/T)$, where $F_c$
is the free energy of the critical bubble. We then compare this exact
calculation to various approximations that have been used in previous work. We
find that these approximations all *overestimate* the activation rate.
Furthermore, we study the effect of finite baryon number upon the bubble
profile and the activation barriers. We find that beyond a critical baryon
number the activation barriers disappear altogether.


title: Family Symmetries and Proton Decay

abstract:
  The proton decay modes $p\to K^0 e^+$ and $p\to K^0 \mu^+$ may be visible in
certain supersymmetric theories, and if seen would provide evidence for new
flavor physics at extremely short distances. These decay modes can arise from
the dimension five operator $(Q_1Q_1Q_2L_{1,2})$, where $Q_i$ and $L_i$ are
${i^{th}}$ generation quark and lepton superfields respectively. Such an
operator is not generated at observable levels due to gauge or Higgs boson
exchange in a minimal GUT. However in theories that explain the fermion mass
hierarchy, it may be generated at the Planck scale with a strength such that
the decays $p\to K^0 \ell^+$ are both compatible with the proton lifetime and
visible at Super-Kamiokande. Observable proton decay can even occur in theories
without unification.


title: Radiative B-decay as a test of CKM unitarity

abstract:
  We point out that $R \equiv Br(b\rightarrow d \gamma)/Br(b\rightarrow s
\gamma)$ is a sensitive probe of possible violation of CKM unitarity. We
compute $R$ in a minimal extension of the Standard Model containing an
additional isosinglet charge ($-1/3$) quark, which leads to a deviation from
CKM unitarity.


title: Introduction to Extended Nambu-Jona-Lasinio Models

abstract:
  A short introduction to quark models with four fermion terms and their
predictions for the parameters of low-energy effective Lagrangians is given.
Special attention is paid to predictions that are as general as possible.
Contribution to the Second DAPHNE Physics Handbook, eds. L. Maiani, G. Pancheri
and N. Paver.


title: On the Ward Identities at Finite Temperature

abstract:
  We show both in 1+1 and 3+1 dimensions that, contrary to the recent
suggestions, the contribution of the fermion loop to the polarization tensor is
manifestly transverse at finite temperature. Some subtleties associated with
the Ward identities at finite temperature are also pointed out.


title: New constraints on supergravity models from $b\to s\gamma$

abstract:
  We perform a detailed study of the constraints from $b\to s\gamma$ on a large
class of supergravity models, including generic four-parameter supergravity
models, the minimal $SU(5)$ supergravity model, and $SU(5)\times U(1)$
supergravity. For each point in the parameter spaces of these models we obtain
a range of $B(b\to s\gamma)$ values which should conservatively account for the
unknown next-to-leading-order QCD corrections. We then classify these points
into three categories: ``excluded" points have ranges of $B(b\to s\gamma)$
which do not overlap with the experimentally allowed range, ``preferred" points
have $B(b\to s\gamma)$ ranges which overlap with the Standard Model prediction,
and ``Ok" points are neither ``excluded" nor ``preferred" but may become
``excluded" should new CLEO data be consistent with the Standard Model
prediction. In {\em all} cases we observe a strong tendency for the
``preferred" points towards one sign of the Higgs mixing parameter $\mu$. For
the opposite sign of $\mu$ there is an upper bound on $\tan\beta$:
$\tan\beta\lsim25$ in general, and $\tan\beta\lsim6$ for the ``preferred"
points. We conclude that new CLEO data will provide a decisive test of
supergravity models.


title:
QCD Corrections to $b\bar b/c\bar c$ Pair Production in Polarized
  $\gamma\gamma$ Collisions and the Intermediate Mass Higgs Signal

abstract:
  We present production rates of the two- and three-jet final states for the
processes of massive $c\bar c/b\bar b$ quark production in circularly polarized
photon-photon collisions, including QCD radiative corrections. Lowest order
cross section, one-loop virtual correction and gluon emission correction are
shown to be of the same order of magnitude for $b\bar b$ quark production at
$\sqrt{s_{\gamma\gamma}}\sim 100$~GeV. It is shown that the signal from
intermediate mass Higgs boson is observable at photon-photon collider, although
the statistical significance is substantially reduced with respect to the tree
level calculation.


title: The SLD Asymmetry in View of the LEP Results

abstract:
  LEP determines $\sin^2 \theta_{\rm eff}$, by combining the various asymmetry
measurements to be $0.2321 \pm 0.0005$. On the other hand, the left-right
asymmetry as measured at SLC corresponds to \seff = $0.2292 \pm 0.0010$. I will
discuss the possibilities of this being i) a statistical fluctuation, ii) a
hint for New Physics or iii) an experimental discrepancy.


title: Higgs particles at future hadron and electron-positron colliders

abstract:
  The prospects for discovering Higgs particles and studying their fundamental
properties at future high-energy electron-positron and hadron colliders are
reviewed. Both the Standard Model Higgs boson and the Higgs particles of its
minimal supersymmetric extension are discussed. We update various results by
taking into account the new value of the top quark mass obtained by the CDF
Collaboration and by including radiative corrections some of which have been
calculated only recently.


title: QCD corrections to Higgs boson self--energies and fermionic decay widths

abstract:
  We present the QCD corrections to Higgs boson self-energies for arbitrary
momentum transfer and for different internal quark masses, to treat the case of
CP--even, CP--odd and charged Higgs bosons which appear in extensions of the
Standard Model scalar sector. Using Ward Identities, we then relate these
results obtained by directly evaluating the relevant two--loop Feynman diagrams
to the known expressions for the electroweak vector boson vacuum polarization
functions. Finally, we derive the exact analytical expressions for the QCD
corrections to the decays of these Higgs particles into quark pairs in the
general case, and reproduce in a completely independent way known results in
some special cases.


title:
Leading electroweak correction to Higgs boson production at proton
  colliders

abstract:
  At proton colliders, Higgs particles are dominantly produced in the
gluon--gluon fusion mechanism. The Higgs--gluons coupling is mediated by heavy
quark loops, and the process can serve to count the number of heavy strongly
interacting particles whose masses are generated by the Higgs mechanism. We
present the two--loop leading electroweak radiative correction to this
coupling, which is quadratically proportional to the heavy quark masses. It
turns out thatthis correction is well under control across the physically
interesting quark mass ranges.


title: The Search for Higgs Bosons: A Summary

abstract:
  I summarize the prospects for discovering Higgs bosons at future $pp$ and
$\ee$ colliders both in the Standard Model and its Minimal Supersymmetric
extension.


title: Nonperturbative QCD Effects in Inclusive B Decays

abstract:
  In this talk I report calculable nonperturbative QCD effects to the inclusive
semileptonic and radiative B-meson decay rates. Small instantons contribute to
the Wilson coefficient functions at scales below $m_b$. It is found that the
instantons give rise to a potentially large correction to the decay rate near
the boundaries of the phase space for the semileptonic decay case, but totally
negligible for the radiative case. I explain how the difference may be
understood as a simple consequence of different kinematics in the two cases.
{Talk Presented at IFT Workshop on Yukawa Couplings and the Origin of Mass
  University of Florida, Gainesville, Feb. 11-13, 1994
  Proceeding to be Published by International Press, 15 pages (LATEX)
  5 Postscript figures available upon request,
  International Press macro file ip-author.sty appended}


title: The Donnachie-Landshoff Pomeron vs. QCD

abstract:
  The Donnachie-Landshoff model of diffractive scattering, which accounts for
all confirmed diffractive data, is briefly reviewed. The picture emerging from
this model is shown to directly contradict that coming from perturbative
leading-log s calculations. The inclusion of non-perturbative effects brings
the two pictures in closer agreement.


title: Fermi motion parameter $p_F$ of $B$ meson from relativistic quark model

abstract:
  The Fermi motion parameter $p_{_F}$ is the most important parameter of ACCMM
model, and the value $p_{_F} \sim 0.3$ GeV has been used without clear
theoretical or experimental evidence. So, we attempted to extract the possible
value for $p_{_F}$ theoretically in the relativistic quark model using quantum
mechanical variational method. We obtained $p_{_F} \sim 0.5$ GeV, which is
somewhat larger than 0.3, and we also derived the eigenvalue of $E_B \simeq
5.5$ GeV, which is is reasonable agreement with $m_B=5.28$ GeV.


title: Unusual Events in Neutrino Telescopes: Signatures of New Physics

abstract:
  A class of physical phenomena outside the framework of the perturbatively
treated Standard Model of electroweak and strong interactions gives rise to
characteristic signatures in neutrino telescopes. In essence, the signature is
a large energy deposition in the neighborhood of the telescope, giving rise to
large and concentrated Cherenkov light emission, and in some cases, to
energetic muon bundles.


title: Weak Scale Threshold Corrections in Supersymmetric Models

abstract:
  I discuss the weak scale threshold corrections in supersymmetric models. I
describe the ``match and run" approximation to the threshold corrections and
compare with the exact one-loop results. With explicit examples I show that in
cases without large hierarchies in the mass spectra the ``match and run"
approximation can lead to order $\cal{O}$(1) errors in the determination of the
threshold corrections. I demonstrate how to obtain the threshold-corrected
Yukawa coupling from the fermion pole mass. I present corrections to the top
quark and squark/slepton masses as a function of the GUT scale parameters $m_0$
and $m_{1/2}$ and show that the gauge/Higgs sector corrections to the top quark
mass are small while the gluino correction can be larger than the well known
gluon correction.


title: Negative s and Light New Physics

abstract:
  Motivated by the difference between SLD's recent measurement of ALR and the
corresponding LEP results, we explore which kinds of new particles can (1)
contribute dominantly to new physics through oblique corrections, (2) produce
negative values for S and T, and (3) not be in conflict with any other
experiments, on or off the Z resonance. We are typically led to models which
involve new particles which are not much heavier than MZ/2, and so which may
also have implications for other experiments in the near future. For such light
particles, we show how the oblique-parameter analysis of purely Z-pole data
requires the interpretation of the data in terms of modified parameters, S' and
T', whose difference from S and T improves the available parameter space of the
models.


title:
The Spin Dependence of Diffractive Processes and Implications for the
  Small $x$ Behaviour of $g_1$ and the Spin Content of the Nucleon

abstract:
  We show that if the Lorentz transformation properties of diffraction are
other than scalar, the $x \rightarrow 0$ behaviour of $g_1(x,Q^2)$ can grow. We
compare with new data on $g_1^p$ from SMC, assess implications for sum rules
and for future studies of sea polarisation.


title: Photon structure and the $\mu$ puzzle

abstract:
  In this talk I first briefly explain the puzzle presented by the high muon
content observed in air-showers which point to the ultra high-energy $\gamma$
sources like the HER-X-1. Since it had been suggested that a possible
explanation of the puzzle might come from the effects of the hadronic structure
of the photon, I briefly explain the concept of photon structure function and
comment on the uncertainties in the predictions of the \sigtot. Then I show
that while the current experiments at the \eplem\ (TRISTAN and LEP) and $ep$
(HERA) colliders have seen clear evidence for the hadronic structure of the
photon, the observed muon excess in the air shower experiments, if confirmed by
other experiments to be at the same high level, can not be explained in terms
of the photon structure function.


title: Exclusive Production of Higgs Bosons in Hadron Colliders

abstract:
  We study the exclusive, double--diffractive production of the Standard Model
Higgs particle in hadronic collisions at LHC and FNAL (upgraded) energies. Such
a mechanism would provide an exceptionally clean signal for experimental
detection in which the usual penalty for triggering on the rare decays of the
Higgs could be avoided. In addition, because of the color singlet nature of the
hard interaction, factorization is expected to be preserved, allowing the
cross--section to be related to similar hard--diffractive events at HERA.
Starting from a Fock state expansion in perturbative QCD, we obtain an estimate
for the cross section in terms of the gluon structure functions squared of the
colliding hadrons. Unfortunately, our estimates yield a production rate well
below what is likely to be experimentally feasible.


title: Fermion Scattering off a CP-Violating Electroweak BubbleWall II

abstract:
  By treating CP-violating interaction as a perturbative term, we solved in a
previous paper the Dirac equation in the background of electroweak bubble wall,
and obtained the transmission and reflection coefficients for a chiral fermion
incident from the symmetric-phase region. We give the transmission and
reflection coefficients under the other boundary condition, that is, the case
of the fermion incident from the broken-phase region. There hold the respective
sets of unitarity relations and also reciprocity relations among them. These
relations enable us to obtain a simple form of quantum-number flux through the
bubble wall, which is the first order quantity of the CP violation. A factor in
the integrand of the flux, which originates from the CP violation, is very
sensitive to the functional form of the CP-violating phase. The absolute value
of this factor is found to decrease as $m_0/a$ increases for $m_0/a
{}~\roughly{>}~1$, where $1/a$ is the wall thickness and $m_0$ the fermion mass
near the critical temperature.


title:
The Infrared Fixed Point of the Top Quark Mass and its Implications
  within the MSSM

abstract:
  We analyse the general features of the Higgs and supersymmetric particle
spectrum associated with the infrared fixed point solution of the top quark
mass in the Minimal Supersymmetric Standard Model. We consider the constraints
on the mass parameters, which are derived from the condition of a proper
radiative electroweak symmetry breaking in the low and moderate $\tan\beta$
regime. In the case of universal soft supersymmetry breaking parameters at the
high energy scale, the radiative $SU(2)_L \times U(1)_Y$ breaking, together
with the top quark Yukawa fixed point structure imply that, for any given value
of the top quark mass, the Higgs and supersymmetric particle spectrum is fully
determined as a function of only two supersymmetry breaking parameters. We show
that, for the interesting range of top quark mass values $M_t\simeq 175\pm 10$
GeV, both a light chargino and a light stop may be present in the spectrum. In
addition, for a given top quark mass, the infrared fixed point solution of the
top quark Yukawa coupling minimizes the value of the lightest CP-even Higgs
mass $m_h$. The resulting upper bounds on $m_h$ read $m_h \leq 90 \;(105)
\;(120)$ GeV for $M_t \leq 165 \;(175) \;(185)$ GeV.


title: Soft Supersymmetry Breaking Parameters and Minimal SO(10) Unification

abstract:
  The minimal supersymmetric SO(10) model, in which not only the gauge but also
the third generation fermion Yukawa couplings are unified, provides a simple
and highly predictive theoretical scenario for the understanding of the origin
of the low energy gauge interactions and fermion masses. In the framework of
the MSSM, with universal soft supersymmetry breaking parameters at the grand
unification scale, large values of the universal gaugino mass $M_{1/2}\geq 300$
GeV are needed in order to induce a proper breakdown of the electroweak
symmetry. In addition, in order to obtain acceptable experimental values for
both the pole bottom mass and the $b\rightarrow s\gamma$ decay rate, even
larger values of the gaugino masses are required. The model is strongly
constrained by theoretical and phenomenological requirements and a heavy top
quark, with mass $M_t\geq 170$ GeV, is hard to accomodate within this scheme.
However, we show that to accommodate a top quark mass $M_t\simeq180$ GeV, it is
sufficient to relax the condition of universality of the scalar soft SUSY
breaking parameters at the grand unification scale. Still, the requirement of a
heavy top quark demands a very heavy squark spectrum, unless specific relations
between the soft SUSY breaking parameters are fulfilled.


title: Structure of proton and nuclei

abstract:
  We discuss in this set of lectures the structure of proton/neutron as
revealed through a study of form-factors. This is followed by a discussion of
the structure functions of proton/nuclear targets as measured in the deep
inelastic scattering (DIS) of leptons off these targets. We discuss the parton
model in DIS as well as outline the usage of parton model in processes other
than the DIS. We then go on to dicsuss the EMC effect: the nuclear dependence
of the structure functions. After a discussion of different models of the EMC
effect we end by pointing out the possibility of distinguishing between these
different models by studying the correlation between the $A$--dependence of
different hard processes and the EMC effect.


title: Semiclassical Meson-Baryon Dynamics from Large-Nc QCD

abstract:
  The large-$N_c$ limit of the meson-baryon effective Lagrangian is shown to
reduce to a semiclassical field theory. A chiral bag structure emerges
naturally in the $N_c\rightarrow \infty$ limit. A possible connection between
the chiral bag picture and the Skyrme model is discussed. The classical
meson-baryon theory is used to reproduce the $M_\pi^3$ non-analytic correction
to the baryon mass obtained previously as a loop correction in chiral
perturbation theory.


title: A Renormalization Group Approach to the Chiral Transition

abstract:
  A methodology is given to test the QCD $N_f$=2 chiral transition, presently
conjectured to be second order. Scaling forms for the correlation length,
susceptibilities and equation of state are given which account for finite
lattice spacing. Confirmation by lattice simulation would provide a large set
of consistency checks for establishing that the transition is second order.
Further corrections from finite volume effects and higher dimensional operator
mixing are given. The implications of scaling corrections in finite temperature
lattice QCD studies are examined with emphasis on tests for the believed second
order chiral transition within the realistic setting of finite lattice spacing
effects.


title: The Partonic Content of $h_1(x)$ and $h_2(x)

abstract:
  A light-cone wavefunction interpretation is presented for the polarized
distribution functions $h_1(x)$ and $h_2(x)$. All matrix elements for moments
of these distributions are given in terms of overlap integrals between Fock
state amplitudes of the target state. In a suitable spinor basis, $h_1(x)$
involves only diagonal matrix elements so can be interpreted as a density.
Matrix elements of $h_2(x)$ connect Fock states differing by one gluon so that
$h_2(x)$ has no simple interpretation as a density. Nevertheless, in the
wavefunction decomposition, $h_2(x)$ is described through a compact set of
elementary quark-gluon processes which are averaged over the target
wavefunction.


title: Heavy Quark Symmetry and the Skyrme Model

abstract:
  We present a consistent way of describing heavy baryons containing a heavy
quark as bound states of an $SU(2)$ soliton and heavy mesons. The resulting
mass formula reveals the heavy quark symmetry explicitly. By extending the
model to the orbitally excited states, we establish the generic structure of
the heavy baryon spectrum. As anticipated from the heavy quark spin symmetry,
the $c$-factor denoting the hyperfine splitting constant {\em vanishes} and the
baryons with the same angular momentum of light degrees of freedom form
degenerate doublets. This approach is also applied to the pentaquark exotic
baryons, where the conventional $c$-factor plays no more a role of the
hyperfine constant. After diagonalizing the Hamiltonian of order $N_c^{-1}$, we
get the degenerate doublets, which implies the vanishing of genuine hyperfine
splitting.


title: Beyond the MSSM

abstract:
  To increase the predictivity of the Minimal Supersymmetric Standard Model
(MSSM), one needs to go to an underlying, more fundamental theory, where at
least some of the many MSSM parameters can be determined by symmetries or by
dynamics. Progress may come from four-dimensional superstring solutions and
their effective supergravities. Summarizing some recent work, we introduce a
class of `large-hierarchy-compatible' (LHC) models that could naturally embed a
stable hierarchy m_Z ~ m_{3/2} << \mpl. We discuss how in LHC models one may
determine: 1) the explicit mass terms of the MSSM, as functions of the
gravitino mass; 2) the scales of gauge and supersymmetry breaking, m_Z and
m_{3/2}; 3) the heavy-fermion masses. Based on talks given at: the Second IFT
Workshop on Yukawa Couplings, Gainesville, Florida, USA, 11--13 February 1994;
the XXIXth Rencontres de Moriond, M\'eribel, France, 12--19 March 1994; the
First International Conference on Phenomenology of Unification from Present to
Future, Rome, Italy, 23--26 March 1994.


title:
Cross section for $ \gamma \gamma \rightarrow \pi^+ \pi^- \pi^0 $ in
  chiral perturbation theory

abstract:
  We give the amplitude for $\gamma\gamma \rightarrow \pi^+\pi^-\pi^0$ in
leading order chiral perturbation theory. For the case of real photons we
calculate the total and differential cross section. Furthermore, we give the
dependence of the total cross section on the invariant mass of one of the
photons.


title: Probing Lumps of Wee Partons in Deep Inelastic Scattering

abstract:
  Recently, the ZEUS collaboration has reported on several remarkable
properties of events with a large rapidity gap in deep inelastic scattering. We
suggest that the mechanism underlying these events is the scattering of
electrons off lumps of wee partons inside the proton. Based on an effective
lagrangian approach the $Q^2$-, $x$- and $W$-distributions are evaluated. For
sufficiently small invariant mass of the detected hadronic system, the
mechanism implies leading twist behaviour. The $x$- and $W$-distributions are
determined by the Lipatov exponent which governs the behaviour of parton
densities at small $x$.


title:
Absence of Matter-Induced Flavor-Changing Contribution to Neutrino
  Oscillation Hamiltonian

abstract: Paper withdrawn; ask me if you would like to know the details.