title:
Multidimensional sampling for simulation and integration: measures,
  discrepancies, and quasi-random numbers

abstract:
  This is basically a review of the field of Quasi-Monte Carlo intended for
computational physicists and other potential users of quasi-random numbers. As
such, much of the material is not new, but is presented here in a style
hopefully more accessible to physicists than the specialized mathematical
literature. There are also some new results: On the practical side we give
important empirical properties of large quasi-random point sets, especially the
exact quadratic discrepancies; on the theoretical side, there is the exact
distribution of quadratic discrepancy for random point sets.


title: Heavy-Higgs Lifetime at Two Loops

abstract:
  The Standard-Model Higgs boson with mass $ M_H >> 2M_Z $ decays almost
exclusively to pairs of $W$ and $Z$ bosons. We calculate the dominant two-loop
corrections of $ O( G_F^2 M_H^4 )$ to the partial widths of these decays. In
the on-mass-shell renormalization scheme, the correction factor is found to be
$ 1 + 14.6 % (M_H/TeV)^2 + 16.9 % (M_H/TeV)^4 $, where the second term is the
one-loop correction. We give full analytic results for all divergent two-loop
Feynman diagrams. A subset of finite two-loop vertex diagrams is computed to
high precision using numerical techniques. We find agreement with a previous
numerical analysis. The above correction factor is also in line with a recent
lattice calculation.


title: Doubly charged Higgs at LHC

abstract:
  We have investigated production of doubly charged Higgs particles
$\Delta_{L,R}^{++}$ via WW fusion process in proton-proton collisions at LHC
energies in the framework of the left-right symmetric model. The production
cross section of the right-triplet Higgs is for representative values of model
parameters at femtobarn level. The discovery reach depends on the mass of the
right-handed gauge boson W_R. At best $\Delta_R^{++}$ mass up to 2.4 TeV are
achievable within one year run. For $\Delta^{++}_L$ the corresponding limit is
1.75 TeV which depends on the value of the left-triplet vev v_L. Comparison
with Drell-Yan pair production processes shows that studies of the WW fusion
processes extend the discovery reach of LHC roughly by a factor of two. The
main experimental signal of a produced Higgs would be a hard same-sign lepton
pair. There will be no substantial background due to the Standard Model (SM)
interactions, since in the SM a same-sign lepton pair will always be associated
with missing energy, i.e. neutrinos, due to lepton number conservation.


title: Partons, Factorization and Resummation, TASI95

abstract:
  I review the treatment of high-energy QCD in Minkowski space, with an
emphasis on factorization theorems as extensions of the operator product
expansion. I discuss how the factorization properties of high-energy cross
sections and amplitudes lead to evolution equations that resum large logarithms
for two-scale problems.


title:
Role of Dual Higgs Mechanism in Chiral Phase Transition at Finite
  Temperature

abstract:
  The chiral phase transition at finite temperature is studied by using the
Schwinger-Dyson equation in the dual Ginzburg-Landau theory, in which the dual
Higgs mechanism plays an essential role on both the color confinement and the
spontaneous chiral-symmetry breaking. At zero temperature, the quark condensate
is strongly correlated with the string tension, which is generated by
QCD-monopole condensation, as $\langle {\bar q}q \rangle^{1/3}
\stackrel{\propto}{\scriptstyle \sim} \sqrt{\sigma}$. In order to solve the
finite-temperature Schwinger-Dyson equation numerically, we provide a new
ansatz for the quark self-energy in the imaginary-time formalism. The recovery
of the chiral symmetry is found at high temperature; $T_{_{C}}\sim 100{\rm
MeV}$ with realistic parameters. We find also a strong correlation between the
critical temperature $T_{_{C}}$ of the chiral symmetry restoration and the
strength of the string tension.


title:
Nucleon Parton Distributions at Low Normalization Point in the Large N_c
  Limit

abstract:
  At large N_c the nucleon can be viewed as a soliton of the effective chiral
lagrangian. This picture of nucleons allows a consistent nonperturbative
calculation of the leading-twist parton distributions at a low normalization
point. We derive general formulae for the polarized and unpolarized
distributions (singlet and non-singlet) in the chiral quark-soliton model. The
consistency of our approach is demonstrated by checking the baryon number,
isospin and total momentum sum rules, as well as the Bjorken sum rule. We
present numerical estimates of the quark and antiquark distributions and find
reasonable agreement with parametrizations of the data at a low normalization
point. In particular, we obtain a sizeable fraction of antiquarks, in agreement
with the phenomenological analysis.


title: A Simple General Treatment of Flavor Oscillations

abstract:
  A unique description avoiding confusion is presented for all
flavor-oscillation experiments in which particles of a definite flavor are
emitted from a localized source. The probability for finding a particle with
the wrong flavor must vanish at the position of the source for all times. This
condition requires flavor-time and flavor-energy factorizations which determine
uniquely the flavor mixture observed at a detector in the oscillation region;
i.e. where the overlaps between the wave packets for different mass eigenstates
differ negligibly from 100\%. The translation of a ``gedanken'' experiments
calculations (where measurement is perform in time) is done using the {\it
group} velocity. Energy-momentum (frequency-wave number) and space-time
descriptions are complementary, equally valid and give the same results. The
two identical phase shifts obtained describe the same physics; adding them
together to get a factor of two is double counting.


title:
Theoretical Higgs Mass Bounds in the Standard Model and Supersymmetric
  Extensions

abstract:
  These lectures provide a very basic introduction to different theoretical
limits on the mass of Higgs scalars. Particular attention is devoted to the
pure Standard Model and its Minimal Supersymmetric extension (MSSM). [Lectures
presented at the XXIV ITEP Winter School, Snegiri (Russia), February 96]


title: On gluon masses, colour symmetry, and a possible massive ninth gluon

abstract:
  Gluons acquire a determinate mass from quark loop radiative corrrections and
self-interaction, when these are recomputed with the symmetrical theory of
generalised functions. The colour symmetry may be~$U(3)$ instead of~$SU(3)$.
The symmetry breaks spontaneously and the ninth colour~$SU(3)$ singlet gluon
acquires a very large mass. There may be some experimental support for its
existence.


title: Bounds on the New Generations

abstract:
  We consider the bounds for the values of higgs mass $m_H$ and the mass of the
extra quarks and leptons $m_{extra}$ derived from the stability of electroweak
vacuum and from the absence of Landau pole in Higgs potential. We find that in
the case of the absence of new physics up to the GUT scale the bounds on masses
of 4th generation are so strong that one can hope to discover it at LEP2.


title:
The production of a non-homogeneous classical pion field and the
  distribution of the neutral and charged pions

abstract:
  The probability distribution $dw/df$ as a function of the ratio
$f=n_0/n_{tot}$ of the neutral to total multiplicities is calculated for the
classical pion fields quickly varying in space and time.


title:
Evolution Kernels of Twist-3 Light-Ray Operators in Polarized Deep
  Inelastic Scattering

abstract:
  The twist three contributions to the $Q^2$-evolution of the spin-dependent
structure function $g_2(x)$ are considered in the non-local operator product
approach. Starting from the perturbative expansion of the T-product of two
electromagnetic currents, we introduce the nonlocal light-cone expansion proved
by Anikin and Zavialov and determine the physical relevant set of light-ray
operators of twist three. Using the equations of motion we show the equivalence
of these operators to the Shuryak-Vainshtein operators plus the mass operator,
and we determine their evolution kernels using the light-cone gauge with the
Leibbrandt-Mandelstam prescription. The result of Balitsky and Braun for the
twist three evolution kernel (nonsinglet case) is confirmed.


title: Can Dilepton Suppression be seen in Heavy Ion Experiments ?

abstract:
  Effects of finite temperature correction to the dilepton emission rate in
ultrarelativistic heavy ion collisions have been looked into. It has been seen
that although the $\rho$-peak in the dilepton spectra from the hadronic sector
is suppressed at very high temperatures, almost no effect can be observed in
the space time integrated count rate.


title: Mixing and CP Violation: Status and Prospects

abstract:
  Brief overview of the present status on mixing and CP violation in kaons and
B mesons is given by means of the unitarity triangle. Theoretical predictions
on epsilon'/epsilon are confronted with experimental results. The prospects of
detecting CP violation at high-energy p pbar, p p, e- e+ and mu- mu+ colliders
are discussed in resonant scatterings involving top quarks and/or heavy
scalars. The relevance of the latter for baryogenesis is briefly outlined.


title: $N=1$ supersymmetry and the three loop gauge beta function

abstract:
  We calculate the three loop gauge $\beta$-function for an abelian $N=1$
supersymmetric gauge theory, using DRED. We construct a coupling constant
redefinition that relates the result to the corresponding term in the NSVZ
$\beta$-function, and by generalising this redefinition to the non-abelian case
we derive the DRED three loop gauge $\beta$-function for the non-abelian case.


title: $B$ Decays, Flavour Mixings and CP Violation in the Standard Model

abstract:
  These lectures review the progress made in our present understanding of $B$
decays. The emphasis here is on applications of QCD to $B$ decays and the
attendant perturbative and non-perturbative uncertainties, which limit present
theoretical precision in some cases but the overall picture that emerges is
consistent with the standard model (SM). This is illustrated by quantitatively
analyzing some of the key measurements in $B$ physics.


title: Supersymmetry Studies at Future Linear $e^+e^-$ Colliders

abstract:
  We examine various aspects of supersymmetric particle production at linear
$e^+e^-$ colliders operating at a centre of mass energy of $\sqrt{s}=500$ GeV,
and integrated luminosity of $\int {\cal L}dt=20-50$ fb$^{-1}$. Working within
the framework of the minimal supergravity model with gauge coupling unification
and radiative electroweak symmetry breaking (SUGRA), we study various
signatures for detection of sparticles, taking into account their cascade
decays, and map out the regions of parameter space where these are observable.
We also examine strategies to isolate different SUSY processes from another. In
addition, we perform four detailed SUGRA case studies and examine the
detectability of sparticles when several SUSY processes are simultaneously
occuring. We show that precision mass measurements of neutralinos, sneutrinos
and top-squarks are possible, in addition to previously studied precision mass
measurements of sleptons and charginos.


title: Mixing of Xi_c and Xi_c' Baryons

abstract:
  The mixing angle between the Xi_c and Xi_c' baryons is shown to be small,
with a negligible shift in the Xi_c masses.


title: Comments on Recent Measurements of R_c and R_b

abstract:
  Discrepancies between Standard Model predictions and experimental
measurements of the fractions R_c and R_b of hadronic Z decays to charm and
bottom are investigated. We show that there exists a discrepancy in two
complementary determinations of B(Bbar --> D X). Reducing the branching ratio
B(D0 --> K- Pi+) by about 15% from currently accepted values to 3.50+/-0.21
removes the discrepancy. Since B(D0 --> K- Pi+) calibrates most charmed hadron
yields, the reduced value also eliminates the discrepancy between the predicted
and measured values of R_c and mitigates a problem in semileptonic B decays. A
reduction in B(D0 --> K- Pi+) would also mean that roughly 15% of all D0 and D+
decays have not been properly taken into account. It is shown that if the
missing decay modes involve multiple charged particles, they would be more
likely to pass the requirements for lifetime B tagging at LEP and SLC. This
would mean that the charm tagging efficiency in (Z --> c cbar) has been
underestimated. As a consequence R_b would need to be revised downward,
potentially bringing it in line with the Standard Model prediction.


title:
Solitons in a Baby-Skyrme model with invariance under area preserving
  diffeomorphisms

abstract:
  We study the properties of soliton solutions in an analog of the Skyrme model
in 2+1 dimensions whose Lagrangian contains the Skyrme term and the mass term,
but no usual kinetic term. The model admits a symmetry under area preserving
diffeomorphisms. We solve the dynamical equations of motion analytically for
the case of spinning isolated baryon type solitons. We take fully into account
the induced deformation of the spinning Skyrmions and the consequent
modification of its moment of inertia to give an analytical example of related
numerical behaviour found by Piette et al.. We solve the equations of motion
also for the case of an infinite, open string, and a closed annular string. In
each case, the solitons are of finite extent, so called "compactons", being
exactly the vacuum outside a compact region. We end with indications on the
scattering of baby-Skyrmions, as well as some considerations as the properties
of solitons on a curved space.


title: Macroscopic Universality : Why QCD in Matter is Subtle?

abstract:
  We use a chiral random matrix model with 2N_f flavors to mock up the QCD
Dirac spectrum at finite chemical potential. We show that the 1/N approximation
breaks down in the quenched state with spontaneously broken chiral symmetry.
The breakdown condition is set by the divergence of a two-point function, that
is shown to follow the general lore of macroscopic universality. In this state,
the fermionic fluctuations are not suppressed in the large N limit.


title:
Time and the Evolution of States in Relativistic Classical and Quantum
  Mechanics

abstract:
  A consistent classical and quantum relativistic mechanics can be constructed
if Einstein's covariant time is considered as a dynamical variable. The
evolution of a system is then parametrized by a universal invariant identified
with Newton's time. This theory, originating in the work of Stueckelberg in
1941, contains many questions of interpretation, reaching deeply into the
notions of time, localizability, and causality. Some of the basic ideas are
discussed here, and as an example, the solution of the two body problem with
invariant action-at-a-distance potential is given. A proper generalization of
the Maxwell theory of electromagnetic interaction, implied by the
Stueckelberg-Schr\"odinger dynamical evolution equation and its physical
implications are also discussed. It is also shown that a similar construction
occurs, applying similar ideas, in the theory of gravitation.


title: Pi Pi scattering in an effective chiral Lagrangian

abstract:
  In this talk I summarize a recently proposed mechanism to understand pi pi
scattering to 1 GeV. The model is motivated by the 1/Nc expansion to QCD, and
includes a current algebra contact term and resonant pole exchanges. Chiral
symmetry plays an important role in restricting the form of the interactions.
The existence of a broad low energy scalar (sigma) is indicated.


title: QCD Corrections to Jet Cross Sections in DIS

abstract:
  Next-to-leading order corrections to jet cross sections in deep inelastic
scattering at HERA are studied. The predicted jet rates allow for a precise
determination of $\alpha_s(\mu_R)$ at HERA over a wide range of $\mu_R$. We
argue, that the ``natural'' renormalization and factorization scale is set by
the average $k_T^B$ of the jets in the Breit frame and suggest to divide the
data in corresponding $<k_T^B>$ intervals. Some implications for the
determination of the gluon density and the associated forward jet production in
the low $x$ regime at HERA are briefly discussed.


title: Fusion of strings as a hadronic accelerator

abstract:
  It is shown that the fusion of strings is a source of particle production in
nucleus--nucleus collisions outside the kinematical limits of nucleon--nucleon
collisions. The spectrum of different particles is compared with the high
energy data on p--A collisions obtaining a reasonable agreement. Results for
A--B collisions at $\sqrt{s}=19.4$ AGeV and $\sqrt{s}=200$ AGeV are given. It
is shown that the fusion of strings can accelerate particles up to the highest
energy detected in cosmic rays without help of any additional cosmic
accelerator. Also the rise of the average shower depth of maximun for cosmic
rays in the energy range between $10^{16}$ eV and $10^{19}$ eV can be explained
by the same mechanism without requiring any change in the chemical composition.


title: Role of Nonperturbative Effects in Deep Inelastic Scattering Revisited

abstract:
  Restrictions imposed on the (electromagnetic or weak) current operator by its
commutation relations with the representation operators of the Poincare group
are considered in detail. We argue that the present theory of deep inelastic
scattering based on perturbative QCD does not take into account the dependence
of the current operator on the nonperturbative part of the quark-gluon
interaction which cannot be neglected even in leading order in $1/Q$, where $Q$
is the magnitude of the momentum transfer.


title:
Generalized Bunching Parameters and Multiplicity Fluctuations in
  Restricted Phase-Space Bins

abstract:
  Experimental aspects of the use of bunching parameters are discussed. Special
attention is paid to the behavior expected for the case of purely statistical
fluctuations. We studied bin-averaged bunching parameters and propose a
generalization of bunching parameters, making use of the interparticle
distance-measure technique. The proposed method opens up the possibility of
carrying out a comprehensive and sensitive investigation of multiplicity
fluctuations inside jets.


title:
Electro-Magnetic Nucleon Form Factors and their Spectral Functions in
  Soliton Models

abstract:
  It is demonstrated that in simple soliton models essential features of the
electro-magnetic nucleon form factors observed over three orders of magnitude
in momentum transfer $t$ are naturally reproduced. The analysis shows that
three basic ingredients are required: an extended object, partial coupling to
vector mesons, and relativistic recoil corrections. We use for the extended
object the standard skyrmion, one vector meson propagator for both isospin
channels, and the relativistic boost to the Breit frame. Continuation to
timelike $t$ leads to quite stable results for the spectral functions in the
regime from the 2- or 3-pion threshold to about two rho masses. Especially the
onset of the continuous part of the spectral functions at threshold can be
reliably determined and there are strong analogies to the results imposed on
dispersion theoretic approaches by the unitarity constraint.


title: The Intrinsic Glue Distribution at Very Small x

abstract:
  We compute the distribution functions for gluons at very small x and not too
large values of transverse momenta. We extend the McLerran-Venugopalan model by
using renormalization group methods to integrate out effects due to those
gluons which generate an effective classical charge density for
Weizs\"acker-Williams fields. We argue that this model can be extended from the
description of nuclei at small x to the description of hadrons at yet smaller
values of x. This generates a Lipatov like enhancement for the intrinsic gluon
distribution function and a non-trivial transverse momentum dependence as well.
We estimate the transverse momentum dependence for the distribution functions,
and show how the issue of unitarity is resolved in lepton-nucleus interactions.


title: Hints of Dynamical Symmetry Breaking?

abstract:
  There is current interest in a possible new massive gauge boson $X$ which
mixes slightly with the $Z$ boson and accounts for certain anomalies in the LEP
data. We show why constraints on models in which the $X$ boson does not couple
to the first two families suggest dynamical electroweak symmetry breaking. The
associated TeV mass fermions make up a fourth family. Constraints on the
effects of the fourth left-handed neutrino also suggest a dynamical origin for
its Majorana mass. We finally comment on related implications for the origin of
quark masses.


title: Heavy Charged Lepton Production In Superstring Inspired E6 Models

abstract:
  We investigate the possibility of studying E$_6$ phenomenology at high energy
hadron colliders. The production of heavy leptons pairs {\it via} a gluon-gluon
fusion mechanism is discussed. An enhancement in the parton level cross-section
is expected due to the heavy (s)fermion loops which couple to the gluons.


title: Spin dependence of the masses of heavy baryons

abstract:
  It is argued from the systematics of spin-depen\-dent forces between quarks
that two proposed baryon states, named $\Sigma_c(2380)$ and $\Sigma_b(5760)$,
do not exist.


title: SUSY and the decay H_2^0-->gg

abstract:
  In this talk I present a detailed SUSY QCD calculation of the decay rate of
the lightest Higgs boson $H^0_2$\ into two gluons, where all quarks and scalar
quarks are taken within the relevant loop diagrams. I include the mixing of all
the three generations of the scalar partners of the left and right handed
quarks and show that their contribution is comparable to the quark contribution
in the MSSM for small values of the soft SUSY breaking parameter $m_S$.
Furthermore in the MSSM the contribution from the bottom quark becomes as large
as the top quark contribution for large $\tan\beta$\ and large Higgs masses. As
a result, the two gluon decay rate of $H_2^0$\ is much larger than the two
gluon decay rate of an equal mass standard model Higgs boson. I further compare
the decay mode of $H^0_2\rightarrow gg$\ to the similar decay modes of
$H^0_2\rightarrow c\overline c$\ including one loop QCD corrections and show
that in some cases $\Gamma(H^0_2\rightarrow gg)$\ is even higher than
$\Gamma(H^0_2\rightarrow c\overline c)$.


title: D-Term Inflation

abstract:
  We show that inflation which is dominated by the D-term density avoids the
`slow-roll' problem of inflation in supergravity. Such an inflationary scenario
can naturally emerge in theories with non-anomalous or anomalous U(1) gauge
symmetry. In the latter case the scale of inflation is fixed by the
Green--Schwarz mechanism of anomaly cancellation. The crucial point is that the
(super)gravity-mediated curvature of all the scalar fields (and, in particular,
of the inflaton), which in the standard F-dominated case is of the order of the
Hubble parameter, is absent in the D-term inflation case. The curvature of
moduli and of all other flat directions during such an inflation crucially
depends on their gauge charges.


title: Weak Radiative Decays of Beauty Baryons

abstract:
  Weak radiative decays of beauty baryons into strange baryons, induced by the
electroweak penguin, are estimated by using a quark model approach. Relations
between formfactors in the semileptonic and in the weak radiative decays are
derived within the heavy quark effective theory. The partial decay widths are
found to be of the order of $10^{-15}{\rm MeV}$ for
$\Lambda_b\rightarrow\Lambda\gamma$ and $\Xi_b\rightarrow\Xi\gamma$ and of the
oder of $10^{-13}{\rm MeV}$ for $\Omega_b\rightarrow\Omega\gamma$. The
$\Omega_b$ radiative decay is thus expected at the sizable branching ratio of
approximately $10^{-4}$.


title: Heavy Quarkonia: Wilson Area Law, Stochastic Vacuum Model and Dual QCD

abstract:
  The $Q \bar{Q}$ semirelativistic interaction in QCD can be simply expressed
in terms of the Wilson loop and its functional derivatives. In this approach we
present the $Q \bar{Q}$ potential up to order $1/m^2$ using the expressions for
the Wilson loop given by the Wilson Minimal Area Law (MAL), the Stochastic
Vacuum Model (SVM) and Dual QCD (DQCD). We confirm the original results given
in the different frameworks and obtain new contributions. In particular we
calculate up to order $1/m^2$ the complete velocity dependent potential in the
SVM. This allows us to show that the MAL model is entirely contained in the
SVM. We compare and discuss also the SVM and the DQCD potentials. It turns out
that in these two very different models the spin-orbit potentials show up the
same leading non-perturbative contributions and 1/r corrections in the
long-range limit.


title:
Parton distributions: a study of the new HERA data, $\alpha_s$, the
  gluon and $p\bar p$ jet production

abstract:
  New data, especially HERA measurements of the proton structure function at
small $x$, allow the opportunity to improve our knowledge of the gluon and
quark distribution functions. We perform a global analysis which incorporates
these new precise data, and which extends down to $Q^2 = 1.5\; GeV^2$. We
discuss the sensitivity to the value of $\alpha_s$ and the improvement in the
determination of the gluon. We compare the predictions of the single jet
inclusive cross section with recent measurements from the Fermilab Tevatron.


title:
Spin - Dependent Parton Distributions of the Longitudinally Polarized
  Photon Beyond the Leading Order

abstract:
  A next-to-leading order (NLO) QCD analysis of the spin-dependent parton
distributions $\Delta f^{\gamma}(x,Q^2)$ of the longitudinally polarized photon
and of its structure function $g_1^{\gamma}(x,Q^2)$ is performed within the
framework of the radiative parton model. The important issues of a suitably
chosen factorization scheme and related boundary conditions are discussed in
detail. The typical effects of the NLO corrections are quantitatively studied
for two very different conceivable scenarios for the NLO polarized parton
distributions $\Delta f^{\gamma}(x,Q^2)$.


title:
The transverse polarized structure function in DIS and chiral symmetry
  breaking in QCD

abstract:
  We study the polarized structure functions in QCD. We show that $g_T$ which
probes helicity flip interactions in hadrons on the light-front indeed measures
the QCD dynamics of chiral symmetry breaking. The relation between chiral
symmetry breaking and the observed $g_2$ data is explored.


title: On Spherically-Symmetric Solutions in the Two-Higgs Standard Model

abstract:
  We report the results of a numerical search for non-topological solitons in
the two-Higgs standard model, characterized by the non-trivial winding,
$\pi_3(S^3)$, of the relative phase of the two doublets. In a region of
(weak-coupling) parameter space we identify a branch of winding solutions,
which are lower in energy than the embedded standard sphaleron and deformed
(bi)sphalerons. Contrary, however, to what happens in 2d toy models, these
solutions remain unstable even for very large Higgs masses.


title: Relativistic two-photon and two-gluon decay rates of heavy quarkonia

abstract:
  The decay rates of $c\bar{c}$ and $b\bar{b}$ through two-photon or two-gluon
annihilations are obtained by using totally relativistic decay amplitudes and a
sophisticated quantum-chromodynamic potential model for heavy quarkonia. Our
results for the photonic and gluonic widths of the 1S0, 3P0, and the 3P2 states
are in excellent agreement with the available experimental data. The procedures
and mathematical techniques used by us for the treatment of the
fermion-antifermion bound states are also applicable to other decay processes.


title: Soft Interaction of Heavy Fermions

abstract:
  We discuss a formula for the sum of tree diagrams of $n$-bosons scattering
from a heavy fermion. This formula can be considered as a generalization of the
eikonal formula to include non-abelian vertices. It will be used to demonstrate
the consistency of multi-meson-fermion scattering in the large-$N_c$ limit.


title: Multiple Reggeon Exchange from Summing QCD Feynman Diagrams

abstract:
  Multiple reggeon exchange supplies subleading logs that may be used to
restore unitarity to the Low-Nussinov Pomeron, provided it can be proven that
the sum of Feynman diagrams to all orders gives rise to such multiple regge
exchanges. This question cannot be easily tackled in the usual way except for
very low-order diagrams, on account of delicate cancellations present in the
sum which necessitate individual Feynman diagrams to be computed to subleading
orders. Moreover, it is not clear that sums of high-order Feynman diagrams with
complicated criss-crossing of lines can lead to factorization implied by the
multi-regge scenario. Both of these difficulties can be overcome by using the
recently developed nonabelian cut diagrams. We are then able to show that the
sum of $s$-channel-ladder diagrams to all orders does lead to such multiple
reggeon exchanges.


title: Effective Higgs-to-Light-Quark Coupling Induced by Heavy Quark Loops

abstract:
  We study the coupling arising via perturbative QCD of zero 4-momentum Higgs
bosons to light quarks inside the nucleon. Qualitative comparison with the
results obtained from one-loop-order low energy theorems for the Higgs-nucleon
interaction suggests the existence of a dynamical light-quark mass which falls
off with momentum. Quantitative comparison leads to an estimate of $\alpha_s$
at very low $q^2$ quite near unity.


title:
Semiclassical treatment of matter-enhanced neutrino oscillations for an
  arbitrary density profile

abstract:
  The matter-enhanced oscillations of two neutrino flavors are studied using a
uniform semiclassical approximation. Unlike some analytic studies which have
focused on certain exactly-solvable densities, this method can be used for an
arbitrary monotonic density profile. The method is applicable to a wider range
of mixing parameters than previous approximate methods for arbitrary densities.
The approximation is excellent in the adiabatic regime and up to the extreme
nonadiabatic limit. In particular, the range of validity for this approximation
extends farther into the nonadiabatic regime than for the linear Landau-Zener
result. This method also allows calculation of the source- and
detector-dependent terms in the unaveraged survival probability, and analytic
results for these terms are given. These interference terms may be important in
studying neutrino mixing in the sun or in supernovae.


title: Nonleptonic Decays and Lifetimes of b-quark and c-quark Hadrons

abstract:
  We review recent experimental results on lifetimes and hadronic decays of
hadrons that contain $c$ and $b$ quarks. The theoretical implications of these
results are also considered. An understanding of hadronic decays of heavy
quarks is required to interpret the CP violating asymmetries in $B$ decays that
will be observed in experiments planned for the near future.


title: Pion electromagnetic formfactor in the instanton vacuum

abstract:
  We have calculated the 3-point correlation function for the electromagnetic
interaction of the pion in an ensembles of instantons and anti-instantons,
modelling the QCD vacuum. The results are well described by a pion pole and the
pion formfactor is extracted, nicely following a standard monopole fit. The
experimental data on the formfactor are well reproduced, provided an average
instanton size is fixed at ${\bar\rho}=0.35\pm 0.03\fm$, the same as found for
a variety of other correlation functions and was found on the lattice.


title:
Simple decay-lepton asymmetries in polarized e+e- -> t tbar and
  CP-violating dipole couplings of the top quark

abstract:
  We study two simple $CP$-violating asymmetries of leptons coming from the
decay of $t$ and $\o t$ in $e^+e^- \ra \tt$, which do not need the full
reconstruction of the $t$ or $\o t$ for their measurement. They can arise when
the top quark possesses nonzero electric and weak dipole form factors in the
couplings to the photon and $Z$, respectively. Together, these two asymmetries
can help to determine the electric and weak dipole form factors independently.
If longitudinal beam polarization is available, independent determination of
form factors can be done by measuring only one of the asymmetries. We obtain
estimates of 90\% confidence limits that can be put on these form factors at a
future linear $\ee$ collider operating at $\sqrt{s}=500$ GeV.


title:
The Electric Screening Mass in Scalar Electrodynamics at High
  Temperature

abstract:
  We study the screening of static electric fields in massless scalar
electrodynamics at high temperature and zero chemical potential. Effective
field theory methods are used to separate the contributions from the momentum
scales T and eT to the electric screening mass. The effects of the distance
scale 1/T are encoded in the parameters of an effective three-dimensional field
theory. The parameters of the effective Lagrangian can be written as a power
series in e^2. The contribution to physical quantities from the scale 1/eT can
be calculated from perturbation theory in the effective theory and is an
expansion in e starting at e^3. The electric screening mass squared is computed
to order e^4


title:
High energy density fluctuations in terms of factorial moments and
  associated frequency moments

abstract:
  We propose to verify relations between quantities which characterize scaling
properties of high energy density fluctuations in terms of factorial moments
and newly introduced associated frequency moments. Typical examples are
presented in frame of systematics developed in the present paper. It involves
also several sorts of moments applied so far in the search for intermittency
and multifractality. Our approach takes the advantage of relations in which a
linear combination of associated frequency moments reduces statistical
fluctuations to the same extent as it is done by corresponding factorial
moments.


title:
Electroweak Baryogenesis and Constraints on Left-handed Majorana
  Neutrino Masses

abstract:
  The lepton number violating interactions generated by the light Majorana
neutrinos can erase the primordial baryon asymmetry of the universe during the
electroweak phase transition. The Majorana masses of the left-handed neutrinos
are constrained to avoid this problem. These constraints do not depend on the
$(B-L)$ symmetry breaking mechanism.


title: Framework for Naturally Light Singlet Neutrinos

abstract:
  The totality of present neutrino data seems to require four light neutrinos,
but only three of them can be the neutral components of left-handed lepton
doublets. To accommodate one or more naturally light singlet neutrino(s), an
extra U(1) gauge factor is proposed to implement an analogous seesaw mechanism
which accounts for the light doublet neutrinos. Using the constraints of
anomaly cancellation, the property of this U(1) is determined. The most
attractive theoretical framework is that of a supersymmetric $SU(3)_C \times
SU(2)_L \times U(1)_Y \times U(1)_N$ model already proposed.


title: Production of Nonlinear SUSY Higgs Bosons at $e^+ e^-$ Colliders

abstract:
  We investigate the Higgs sector of a nonlinear supersymmetric standard model
at LEP 1 and LEP 2, as well as at future linear $e^+ e^-$ colliders with $\sqrt
s = 500$, 1000, and 2000 GeV. The LEP 1 data do not put any constraints on the
parameters of the model, and allow a massless Higgs boson in particular. For
LEP 2, there are remarkable differences between the Higgs productions at $\sqrt
s = 175$ GeV on the one hand and that at $\sqrt s = 192$ GeV and 205 GeV on the
other hand. The case for $\sqrt s = 175$ GeV is similar to LEP 2, whereas those
for $\sqrt s = 192$ GeV and 205 GeV will be able to give experimental
constraints on the parameters. Finally the $e^+ e^-$ colliders with $\sqrt s =
500$, 1000, and 2000 GeV are most probably able to test the model conclusively.


title:
Separation of S- wave pseudoscalar and pseudovector amplitudes in pi^-
  p---> pi^+ pi^- n reaction on polarized target

abstract:
  A new analysis of S-wave production amplitudes for the reaction $\pi^-
p_{\uparrow} \rightarrow \pi^+ \pi^- n$ on a transversely polarized target is
performed. It is based on the results obtained by the CERN-Cracow -Munich
collaboration in the pion-pion energy range from 600 MeV to 1600 MeV at 17.2
GeV/c $\pi^-$ momentum. Energy-independent separation of the S-wave
pseudoscalar amplitude ($\pi$ exchange) from the pseudovector amplitude
($a_{1}$ exchange) is carried out using assumptions much weaker than those in
all previous analyses. We show that, especially around 1000 MeV and around 1500
MeV, the $a_{1}$ exchange amplitude cannot be neglected. The scalar-isoscalar
$\pi\pi$ phase shifts are calculated using fairly weak assumptions. Below the
$K\overline{K}$ threshold we find two solutions for the $\pi-\pi$ phase shifts,
for which the phases increase slower with the effective $\pi-\pi$ mass than the
P-wave phases. Both solutions are consistent with a broad $f_{0}(500)$ but only
one is similar to the well-known "down" solution. We find also the third
solution (with a somewhat puzzling behavior of inelasticity) which exhibits a
narrow $f_{0}(750)$ claimed by Svec. All the solutions undergo a rapid change
at the $K\overline{K}$ threshold. Above 1420 MeV the phase shifts increase with
energy faster than those obtained without the polarized-target data. This phase
behavior as well as an increase of the modulus of the $a_{1}$-exchange
amplitude can be due to the presence of the $f_{0}(1500)$.


title:
Effects of QCD Resummation on Distributions of Top--Antitop Quark Pairs
  Produced at the Tevatron

abstract:
  We study the kinematic distributions of top--antitop quark pairs produced at
the Tevatron, including the effects of initial state and final state multiple
soft gluon emission, using the Collins--Soper--Sterman resummation formalism.
The resummed results are compared with those predicted by the showering event
generator PYTHIA for various distributions involving the top--antitop quark
pair and the individual top quark or antiquark. The comparison between the
experimental and predicted distributions will be a strong test of our
understanding and application of perturbative QCD. Our results indicate that
the showering event generators do not produce enough radiation. We reweight the
PYTHIA distributions to agree with our resummed calculation, then use the
reweighted events to better estimate the true hadronic activity in top--antitop
quark pair production at hadron colliders.


title:
Chargino Pair Production at LEP2 with Broken R-Parity: 4-jet Final
  States

abstract:
  We study the pair production of charginos in e+e- collisions followed by the
decay via R-parity violating LQD operators. We determine the complete matrix
element squared for chargino decays via LQD or LLE operators. We find regions
in MSSM parameter space where the chargino mass is 52.5GeV and the R-parity
violating decays of the charginos dominate the gauge decays to neutralinos. At
LEP2 this then leads to additional 4 jet events which could explain the excess
recently observed by ALEPH.


title: Coulomb and strong interactions for Bose-Einstein correlations

abstract:
  We present an analytical formula for the Bose-Einstein correlations (BEC)
which includes effects of both Coulomb and strong final stateinteractions
(FSI). It was obtained by using Coulomb wave function together with the
scattering partial wave amplitude of the strong interactions describing data on
the $s$-wave phase shift. We have proved numerically that this method is
equivalent to solving Schr\"{o}dinger equation with Coulomb and the $s$-wave
strong interaction potentials. As an application we have analysed, using our
formula which includes the degree of coherence and the long range correlation,
the data for $e^+e^-$ annihilations. We have found that the degree of coherence
present in our formula approaches approximately unity whereas the long range
correlation parameter becomes approximately zero. These results suggest that
the physical meanings of the fractional degree of coherence and the long range
correlation observed in various other analyses can most probably be attributed
to FSI.


title:
What information can we obtain from the yield ratio $\pi^-/\pi^+$ in
  heavy-ion collisions ?

abstract:
  The recently reported data on the yield ratio $\pi^-/\pi^+$ in central
rapidity region of heavy-ion collisions are analyzed by theoretical formula
which accounts for Coulomb interaction between central charged fragment (CCF)
consisting of nearly stopped nucleons with effective charge
$Z_{\mbox{\scriptsize eff}}$ and charged pions produced in the same region of
the phase space. The Coulomb wave function method is used instead of the usual
Gamow factor in order to account for the finite production range of pions,
$\beta$. For Gaussian shape of the pion production sources it results in a
quasi-scaling in $\beta$ and $Z_{\mbox{\scriptsize eff}}$ which makes
determination of parameters $\beta$ and $Z_{\mbox{\scriptsize eff}}$ from the
existing experimental data difficult. Only sufficiently accurate data taken in
the extreme small $m_{\scriptscriptstyle T}$-$m_{\pi}$ region, where this
quasi-scaling is broken, could be used for this purpose.


title:
Final state interactions for Bose-Einstein correlations in S+Pb $\to$
  $\pi^+$$\pi^+$ +X reaction at energy 200GeV/nucleon

abstract:
  We applied an analytical formula for Bose-Einstein correlations (BEC)
developed by us recently to high-energy heavy ion collisions, in particular to
data on S+Pb$\to\pi^+$-$\pi^+$+X reaction at energy $200$ GeV/nucleon reported
by the NA44 Collaboration. It takes into account both Coulomb and strong
($\pi$-$\pi$~s-wave; I=2) final state interactions (FSI). We have found that
inclusion of the strong interaction in addition to Coulomb correction affects
significantly the extracted parameters of the BEC like the source size $R$, the
degree of coherence $\lambda$ and the long-range correlation parameter
$\gamma$. In particular, the $\lambda$ parameter of the BEC is increased by
about 20\%. Our results differ from those obtained in $e^+e^-$ annihilation in
the following way: the $\lambda$ parameter does not reach `chaotic limit' and
the $\gamma$ parameter does not approach to zero.


title:
New Analysis of Cumulant Moments in $e^+e^-$ Collisions by SLD
  Collaboration by Truncated Multiplicity Distributions

abstract:
  Newly reported normalized cumulant moments of charged particles in $e^+e^-$
collisions by the SLD collaboration are analyzed by the truncated modified
negative binomial distribution (MNBD) and the negative binomial distribution
(NBD). Calculated result by the MNBD describes the oscillatory behavior of the
data much better than that by the NBD.


title:
Analysis of Cumulant Moments in High Energy Hadron-Hadron Collisions by
  Truncated Multiplicity Distributions

abstract:
  Oscillatory behavior of cumulant moments obtained from the experimental data
in $pp$ collisions and $\bar{p}p$ collisions are analyzed by the modified
negative binomial distribution (MNBD) and the negative binomial distribution
(NBD). Both distributions well describe the cumulant moments obtained from the
data. This fact shows sharp contrast to the result in $e^+e^-$ collisions,
which is described by the the MNBD much better than by the NBD.


title:
Confronting the Minimal Supersymmetric Standard Model with the Study of
  Scalar Leptons at Future Linear e+e- Colliders

abstract:
  Sleptons can easily be found at future linear e+e- colliders if kinematically
accessible. Measurements of their masses and decay distributions would then
determine MSSM parameters. This paper presents a detailed MC study of the
production and decay of the lighter scalar tau lepton, stau1. We found that
mstau1 and the left-right mixing angle of stau would be measured within an
error of a few percent. tanbeta is determinable in some region of the parameter
space through simultaneous studies of stau1-and selectron-pair production: the
polarization measurement of the tau leptons from stau1 decays and the M1, mchi1
determination using selectron pair production and decay. We also point out the
possibility to determine bino-selectron-e coupling through the measurement of
the angular distribution of the selectron-pair production. The error on the
coupling is expected to be comparable to its typical SUSY radiative correction,
which is proportional to log(msquark/mslepton). The radiative correction
affects M1 and tanbeta determination, necessitating the full 1-loop radiative
correction to the selectron production processes. The implication of these
measurements of the MSSM parameters on selecting models of the origin of
supersymmetry breaking is also discussed.


title: Status and Prospects for Lattice Calculations in Heavy Quark Physics

abstract:
  The current status of lattice calculation of weak matrix elements for heavy
quark systems is reviewed. After an assessment of systematic errors in present
simulations, results for the B meson decay constant, the B-parameter B_B and
semi-leptonic heavy-to-light and heavy-to-heavy transitions are discussed. The
final topic are lattice results for heavy baryon spectroscopy.


title: Axion Cosmology with a Stronger QCD in the Early Universe

abstract:
  We examine in the context of supersymmetric models whether the usual
cosmological upper bound on the axion decay constant can be relaxed by assuming
a period of stronger QCD in the early universe. By evaluating the axion
potential in the early universe and also taking into account the dilaton
potential energy, it is argued that a stronger QCD is not useful for raising up
the bound.


title: A Non-perturbative Effect in Deep Inelastic Scattering

abstract:
  The HERA data at large $Q^2$ and small-$x$ investigate large distances on the
light-cone. At such large distances the scattered quarks can maintain their
colour identity by polarizing the vacuum as they transfer energy to it. We
calculate the probability for the creation of quark-antiquark pairs from the
polarized QCD vacuum and their contribution to the structure function.


title: Nonabelian Cut Diagrams and their Applications

abstract:
  A new kind of cut diagram is introduced to sum Feynman diagrams with
nonabelian vertices. Unlike the Cutkosky diagrams which compute the
discontinuity of single Feynman diagrams, the nonabelian cut diagrams represent
a resummation of both the real and the imaginary parts of Feynman diagrams
related by permutations. Several applications of the technique are reported,
including a resolution of the apparent inconsistency of the baryon problem in
large-$N_c$ QCD, a simplified calculation of high-energy low-order QCD
diagrams, and progress made with this technique on the unitarization of the
BFKL equation.


title: Observable jets from the BFKL chain

abstract:
  We derive a modified form of the BFKL equation which enables the structure of
the gluon emissions to be studied in small $x$ deep inelastic scattering. The
equation incorporates the resummation of the virtual and unresolved real gluon
emissions. We solve the equation to calculate the number of small $x$
deep-inelastic events containing 0,1,2 ...resolved gluon jets, that is jets
with transverse momenta $q_{T} > \mu$. We study the jet decomposition for
different choices of the jet resolution parameter $\mu$.


title: Overview of Perturbative QCD

abstract:
  Overview of the perturbative QCD session at Moriond '96: theoretical
techniques and current issues, primarily as applied to jet physics at
colliders.


title: Majorana Neutrinos and Long Range Forces

abstract:
  We establish that forces mediated by the exchange of a pair of Majorana
neutrinos differ from those due to Dirac neutrino exchange.


title: Unitarity-based Techniques for One-Loop Calculations in QCD

abstract:
  We discuss new techniques developed in recent years for performing one-loop
calculations in QCD, and present an example of results from the process 0 -> V
q q-bar g g. Talk presented at the 1996 Zeuthen Workshop on Elementary Particle
Theory, "QCD and QED in Higher Order", Rheinsberg, Brandenburg, April 21-26,
1996.


title:
Chiral-invariant CP-violating Effective Interactions in Z Decays to
  three Jets

abstract:
  Tests of CP violation by appropriate momentum correlations in $Z\to 3$ jets
and in particular in $Z\to b\bar bX$ probe CP-violating effective couplings --
that manifest themselves as form factors -- which conserve the quark chirality
and quark flavour. By giving two examples we show that such couplings can be
induced at one-loop order in extensions of the Standard Model with CP violation
beyond the Kobayashi-Maskawa phase. In one of the models we compute the
chirality-conserving part of the CP-violating $Zb{\bar b}$-gluon amplitude for
massless $b$ quarks, determine the resulting effective dimension $d=6$
couplings in the local limit, and discuss the possible size of the effects.
Finally we show that in models with excited quarks the chiral-invariant
CP-violating effective interactions could be quite large if appropriate
couplings are of a size characteristic of a strong interaction


title: Large-x d/u Ratio in W-boson Production

abstract:
  Recent analysis of proton and deuteron deep-inelastic scattering data have
suggested that the extracted d/u quark distribution ratio at large x may be
significantly larger than previously believed, if the data are corrected for
nuclear binding effects in the deuteron. We examine the sensitivity to the
large-x d/u ratio of lepton asymmetries from W-boson production in p-pbar and
p-p collisions at large rapidity, which do not suffer from nuclear
contamination.


title: The Gauge-Independent QCD Effective Charge

abstract:
  It is shown how the QED concept of a gauge-, scale- and scheme-independent
one-loop effective charge can be extended directly at the diagrammatic level to
QCD, thus justifying explicitly the ``naive non-abelianization'' prescription
used in renormalon calculus. It is first argued that, for on-shell external
fields and at the strictly one-loop level, the required gluon self-energy-like
function is precisely that obtained from S-matrix elements via the pinch
technique. The generalization of the pinch technique to explicitly off-shell
processes is then introduced. It is shown how, as a result of a fundamental
cancellation among conventional perturbation theory diagrams, encoded in the
QCD Ward identities, the pinch technique one-loop gluon self-energy
i\hat{\Pi}_{\mu\nu}^{ab}(q) remains gauge-independent and universal regardless
of the fact that the ``external'' fields in the given process are off-shell.
This demonstration involves a simple technique enabling the isolation, in an
arbitrary gauge, of i\hat{\Pi}_{\mu\nu}^{ab}(q) from subclasses of up to
several hundred diagrams at once. Furthermore, it is shown how this one-loop
cancellation mechanism iterates for the subclasses of n-loop diagrams
containing implicitly the Dyson chains of n one-loop self-energies
i\hat{\Pi}_{\mu\nu}^{ab}(q). The gauge cancellation required for the Dyson
summation of i\hat{\Pi}_{\mu\nu}^{ab}(q) is thus demonstrated explicitly in a
general class of ghost-free gauges for all orders n.


abstract:
  The $O(\alpha m_t^2/m_W^2)$ Yukawa corrections to top pair production in
photon-photon collision are calculated in the standard model (SM), the general
two-Higgs-doublet model (2HDM) as well as the minimal supersymmetric model
(MSSM). We found that the correction to the cross section can only reach a few
percent in the SM, but can be quite significant ($>$10\%) in the 2HDM and MSSM
for favorable parameter values, which may be observable at the high energy
$e^+e^-$ colliders.


title: Abelian Flavour Symmetries in Supersymmetric Models

abstract:
  We propose a theory of flavour based on abelian horizontal gauge symmetries
and modular invariances. We construct explicit supergravity models where the
scale of the horizontal $U(1)$ symmetry breaking is fixed by the Green-Schwarz
mechanism for anomaly cancellation. The supersymmetric spectrum is obtained in
terms of the $U(1)$ charges which are determined by the Yukawa matrices.


title: Gauged SO(3) family symmetry and squark mass degeneracy

abstract:
  It is shown that a gauged SO(3) family symmetry can suppress flavor-changing
processes from squark-mass non-degeneracy to an acceptable level. The
potentially dangerous SO(3) D-terms can be rendered harmless if the
CP-violating phases appearing in the SO(3)-breaking sector are small, which can
naturally be the case if CP is a spontaneously broken symmetry. This approach
has certain advantages over models based on global or non-abelian discrete
symmetries, and dovetails with some recent proposals for explaining the pattern
of quark and lepton masses. Moreover this approach relates the near-degeneracy
of the squark masses to an approximate CP invariance which can also explain the
smallness of the electron and neutron electric dipole moments.


title:
One-loop QCD Corrections to Top Quark Decay into a Neutralino and Light
  Stop

abstract:
  We calculate the one-loop QCD corrections to $t\rightarrow \tilde t_1 \tilde
\chi^0_j$ using dimensional reduction scheme, including QCD and supersymmetric
QCD corrections. The analytic expressions for the corrections to the decay
width are given, which can easily be extended to $t\rightarrow \tilde \chi^+_j
\tilde b_i $. The numerical results show that the correction amounts to more
than a 10\% reduction in the partial width relative to the tree level result.
We also compare the corrections in the no-mixing stop case with those in the
mixing stop case.


title:
Top Quark and Higgs Boson Masses: Interplay between Infrared and
  Ultraviolet Physics

abstract:
  We review recent efforts to explore the information on masses of heavy matter
particles, notably of the top quark and the Higgs boson, as encoded at the
quantum level in the renormalization group (RG) equations. The Standard Model
(SM) and the Minimal Supersymmetric Standard Model (MSSM) are considered in
parallel. First, the question is addressed to which extent the infrared (IR)
physics of the ``top-down'' RG flow is independent of the ultraviolet (UV)
physics. The central issues are i) IR attractive fixed point values for the top
and the Higgs mass, the most outstanding one being m_t=O(190 GeV)sin(beta) in
the MSSM, ii) IR attractive relations between parameters, the most prominent
ones being an IR fixed top-Higgs mass relation in the SM, leading to m_H=O(156)
GeV for the experimental top mass, and an IR fixed relation between the top
mass and tan(beta) in the MSSM, and iii) an analytical assessment of their
respective strengths of attraction. The triviality and vacuum stability bounds
on the Higgs and top masses in the SM and the upper bound on the lightest Higgs
boson mass in the MSSM are reviewed. The mathematical backbone, the rich
structure of IR attractive fixed points, lines, surfaces,... in the
multiparameter space, is made transparent. Interesting hierarchies emerge, most
remarkably: IR attraction in the MSSM is systematically stronger than in the
SM. Tau-bottom-(top) Yukawa coupling unification in supersymmetric grand
unified theories and its power to focus the ``top-down'' RG flow into the IR
top mass fixed point resp. onto the IR fixed line in the m_t-tan(beta) plane is
reviewed. The program of reduction of parameters, a search for RG invariant
relations between couplings, guided by the requirement of asymptotically free
couplings in the UV limit,is summarized; its interrelations with the search for


title:
What would we learn by detecting a gravitational wave signal in the
  cosmic microwave background anisotropy?

abstract:
  Inflation generates gravitational waves, which may be observable in the low
multipoles of the cosmic microwave background (cmb) anisotropy but only if the
inflaton field variation is at least of order the Planck scale. Such a large
variation would imply that the model of inflation cannot be part of an ordinary
extension of the standard model, and combined with the detection of the waves
it would also suggest that the inflaton field cannot be one of the superstring
moduli. Another implication of observable gravitational waves would be a
potential $V^{1/4}=2$ to $4\times 10^{16}\GeV$, which is orders of magnitude
bigger than is expected on the basis of particle theory. It might emerge in a
hybrid inflation model where most of the energy density comes from the Higgs
sector of a GUT, but only if both the vacuum expectation values {\em and the
masses } of the Higgs fields are of this order.


title:
Supersymmetric Neutrino Masses, R Symmetries, and The Generalized mu
  Problem

abstract:
  In supersymmetric models a tree-level neutrino mass could originate from the
(weak-scale) superpotential. We propose and examine a realization of that idea,
which arises naturally in the framework of a spontaneously broken U(1)
R-symmetry. The solution to the neutrino mass problem could shed light in this
framework on the possible resolution of the $\mu$ problem. Furthermore, the
suppression of the neutrino mass in comparison to the weak scale arises
dynamically and need not be encoded in the superpotential. The latter mechanism
operates, for example, in universal models for the soft supersymmetry breaking
terms. Phenomenological and cosmological implications of the model are also
discussed, some of which are shown to hold more generally. We also note that
future signatures could include observable enhancement of dijet and multijet
production rates and a correlation between the supersymmetric and neutrino
spectra.


title: Parton Sum Rules and Improved Scaling Variable

abstract:
  The effect from quark masses and transversal motion on the Gottfried,
Bjorken, and Ellis-Jaffe sum rules is examined by using a quark-parton model of
nucleon structure functions based on an improved scaling variable. Its use
results in corrections to the Gottfried, Bjorken, and Ellis-Jaffe sum rules. We
use the Brodsky-Huang-Lepage prescription of light-cone wavefunctions to
estimate the size of the corrections. We constrain our choice of parameters by
the roughly known higher twist corrections to the Bjorken sum rule and find
that the resulting corrections to the Gottfried and Ellis-Jaffe sum rules are
relevant, though not large enough to explain the observed sum rule violations.


title: Single spin asymmetry of vector meson production in the string model

abstract:
  Azimuthal asymmetry of vector-meson production in single-transversely
polarized proton-proton collisions ($p\up p$) is calculated in a model based on
the string fragmentation. The string is spanned by a valence quark of the
projectile scattered on the target. The asymmetry is generated only during
fragmentation of the scattered quark into hadrons. The obtained asymmetry of
the $\rho$ mesons is opposite in sign to that of pions. On the other hand, if
the asymmetry were generated during the quark scattering then the asymmetries
of the vector and of the pseudoscalar mesons would be close to each other.


title: Polarization and Weak Mixing Angle in High Energy e^\pm e^- Collisions

abstract:
  At a linear collider of the next generation the large event rates expected
from Bhabha and M\o ller scattering may be used to determine simultaneously
sin^2\theta_w and the polarization of both beams with very high accuracy. These
measurements can be performed in parallel to the other tasks of the linear
collider as a free by-product. A high degree of polarization and a good polar
angle coverage of the detectors turn out to be major assets.


title: RS-invariant all-orders renormalon resummations for some QCD observables

abstract:
  We propose a renormalon-inspired resummation of QCD perturbation theory based
on approximating the renormalization scheme (RS) invariant effective charge
beta-function coefficients by the portion containing the highest power of
$b$=$\frac{1}{6}(11N$--$2N_{f})$, for SU($N$) QCD with $N_{f}$ quark flavours.
This can be accomplished using exact large-$N_{f}$ all-orders results. The
resulting resummation is RS-invariant and the exact next-to-leading order (NLO)
and next-to-NLO (NNLO) coefficients in any RS are included. This improves on a
previously employed naive resummation of the leading-$b$ piece of the
perturbative coefficients which is RS-dependent, making its comparison with
fixed-order perturbative results ambiguous. The RS-invariant resummation is
used to assess the reliability of fixed-order perturbation theory for the
$e^{+}e^{-}$ $R$-ratio, the analogous $\tau$-lepton decay ratio $R_{\tau}$, and
Deep Inelastic Scattering (DIS) sum rules, by comparing it with the exact NNLO
results in the effective charge RS. For the $R$-ratio and $R_{\tau}$, where
large-order perturbative behaviour is dominated by a leading ultra-violet
renormalon singularity, the comparison indicates fixed-order perturbation
theory to be very reliable. For DIS sum rules, which have a leading infra-red
renormalon singularity, the performance is rather poor. In this way we estimate
that at LEP/SLD energies ideal data on the $R$-ratio could determine
$\alpha_{s}(M_{Z})$ to three-significant figures, and for the $R_{\tau}$ we
estimate a theoretical uncertainty $\delta\alpha_{s}(m_{\tau})\simeq0.008$
corresponding to $\delta\alpha_{s}(M_{Z})\simeq0.001$. This encouragingly small
uncertainty is much less than has recently been deduced from comparison with
the ambiguous naive resummation.


title: Electroweak corrections to the muon anomalous magnetic moment

abstract:
  The two-loop electroweak radiative corrections to the muon's anomalous
magnetic moment, $a_\mu\equiv (g_\mu-2)/2$, are presented. We obtain an overall
22.6\% reduction in the electroweak contribution $a_\mu^{\rm EW}$ from
$195\times 10^{-11}$ to $151(4)\times 10^{-11}$. Implications for the full
standard model prediction and an upcoming high precision measurement of $a_\mu$
are briefly discussed. Some aspects of the calculations are discussed in
detail.


title:
Probing the equation of state in the AGS energy range with 3-d
  hydrodynamics

abstract:
  The effect of (i) the phase transition between a quark gluon plasma (QGP) and
a hadron gas and (ii) the number of resonance degrees of freedom in the
hadronic phase on the single inclusive distributions of 16 different types of
produced hadrons for Au+Au collisions at AGS energies is studied.
  We have used an exact numerical solution of the relativistic hydrodynamical
equations without free parameters which, because of its 3-d character,
constitutes a considerable improvement over the classical Landau solution.
  Using two different equations of state (eos) - one containing a phase
transition from QGP to the Hadronic Phase and two versions of a purely hadronic
eos - we find that the first one gives an overall better description of the
Au+Au experimental data at $AGS$ energies.
  We reproduce and analyse measured meson and proton spectra and also make
predictions for anti-protons, deltas, anti-deltas and hyperons. The low m_t
enhancement in pi- spectra is explained by baryon number conservation and
strangeness equilibration.
  We also find that negative kaon data are more sensitive to the eos, as well
as the K-/pi- ratio. All hyperons and deltas are sensitive to the presence of a
phase transition in the forward rapidity region. Anti-protons, Omegas and heavy
anti-baryons are sensitive in the whole rapidity range.


title: On the Electron Structure Function

abstract:
  The collinear QCD structure of the electron is studied within the Standard
Model. The electron structure function is defined and calculated in leading
logarithmic approximation. It shows important contribution from the
interference of the intermediate electroweak bosons. The problem of momentum
scales is extensively discussed. The master equations for the QCD parton
densities inside the electron are constructed and solved numerically in the
asymptotic region. Significant corrections to the naive evolution procedure are
found. Phenomenological applications at present and future momentum scales are
discussed.


title: Leptophobic U(1)'s and R_b, R_c at LEP

abstract:
  In the context of explaining the experimental deviations in R_b and R_c from
their Standard Model predictions, a new type of U(1) interaction is proposed
which couples only to quarks. Special attention will be paid to the
supersymmetric \eta-model coming from E_6 which, due to kinetic mixing effects,
may play the role of the leptophobic U(1). This talk summarizes work done with
K.S. Babu and J. March-Russell in hep-ph/9603212.


title: Top Quark Interactions and the Search for New Physics

abstract:
  We give a complete set of 19 independent effective dimension 5 interactions
involving the top and bottom quarks with the electroweak gauge bosons within
the context of the chiral Lagrangian. The anomalous operators contribute to the
leading energy power E^3 of the V_L V_L -> t\bar t or t\bar b amplitudes. We
also show the top quark production rates at the LHC and the LC via V_L V_L
fusion processes. If no anomalous production rate is found, then these
coefficients can be bound (based on the naive dimensional analysis) to be of
order 10^{-2} or 10^{-1}. This is about an order of magnitude more stringent
than the bounds for the next-to-leading order bosonic operators commonly
studied in V_L V_L -> V_L V_L scatterings. The effect on a CP-odd observable is
also briefly discussed.


title:
Electroweak Radiative Corrections to Resonant Charged Gauge Boson
  Production

abstract:
  The electroweak O(alpha) contribution to the resonant single W production in
a general 4-fermion process is discussed with particular emphasis on a gauge
invariant decomposition into a QED-like and weak part. The cross section in the
vicinity of the resonance can be represented in terms of a convolution of a
`hard' Breit-Wigner-cross section, comprising the (m_t,M_H)-dependent weak
1-loop corrections, with an universal radiator function. The numerical impact
of the various contributions on the W line shape are discussed, together with
the concepts of s-dependent and constant width approach. Analytic formulae for
the W decay width are also provided including the 1-loop electroweak and QCD
corrections.


title:
Improved Parton Distributions from Global Analysis of Recent Deep
  Inelastic Scattering and Inclusive Jet Data

abstract:
  The impact of recent precision measurements of DIS structure functions and
inclusive jet production at the Tevatron on the global QCD analysis of parton
distribution functions is studied in detail. Particular emphasis is placed on
exploring the range of variation of the gluon distribution $G(x,Q)$ allowed by
these new data. The strong coupling of $G(x,Q)$ with $\alpha_s$ is fully taken
into account. A new generation of CTEQ parton distributions, CTEQ4, is
presented. It consists of the three standard sets (\mbox{\small {$\overline
{\rm MS}$}}, {\protect \small DIS} and leading order), a series that gives a
range of parton distributions with corresponding $\alpha_s$'s, and a set with a
low starting value of $Q$. Previously obtained gluon distributions that are
consistent with the high $E_t$ jet cross-section are also discussed in the
context of this new global analysis.


title:
Estimation of distribution parameters from statistically limited
  information; muons in KASCADE experiment

abstract:
  The problem of the estimation of distribution parameters in the case of
experimentally limited information is discussed. As an example the
determination of the total number of muons in Extensive Air Showers registered
in the KASCADE experiment is studied in details. Some methods based on other
than standard maximum-likelihood approach are examined. The advantages of the
new methods are shown. The comparison with the Artificial Neural Network
approach is also given.


title: Propagation of Strange Quark Matter in the Atmosphere

abstract:
  We propose model of propagation of lumps of Strange Quark Matter
(strangelets) through the atmosphere, which accounts for their apparent strong
penetrability and normal nuclear-type sizes at the same time. The mass spectrum
of strangelets reaching the Earth predicted by this model agrees very well with
the existing data on the abundance of different elemets in the Universe.


title: Theory of tau mesonic decays

abstract:
  A theory of tau mesonic decays is proposed. The general formula of the
axial-vector currents of mesons is presented. The meson vertices are obtained
from an effective chiral theory of mesons. The vertices depend on momentum.
Many decay modes are studied. Theoretical results agree reasonably well with
the data. There are predictions.


title:
Nonperturbative study of generalized ladder graphs in a \phi^2\chi
  theory

abstract:
  The Feynman-Schwinger representation is used to construct scalar-scalar bound
states for the set of all ladder and crossed-ladder graphs in a \phi^2\chi
theory in (3+1) dimensions. The results are compared to those of the usual
Bethe-Salpeter equation in the ladder approximation and of several
quasi-potential equations. Particularly for large couplings, the ladder
predictions are seen to underestimate the binding energy significantly as
compared to the generalized ladder case, whereas the solutions of the
quasi-potential equations provide a better correspondence. Results for the
calculated bound state wave functions are also presented.


title: Heavy-to-light form factors in the quark model with heavy propagators

abstract:
  We calculate the heavy-to-light form factors in the relativistic quark model
with heavy infrapropagators. Their q^2-dependence in the physical region is
defined by two parameters: the "infrared" parameter \nu characterizing the
infrared behavior of the heavy quark and the mass difference of the heavy meson
and heavy quark E=m_H-M_Q. It is found that the values of the D\to K(K^*) and
D\to \pi(\rho) form factors at q^2=0 are in excellent agreement with the
available experimental data and other approaches whereas these values for B\to
\pi(\rho) transitions are found to be larger than those of several other
models. The obtained form factors are used to calculate the widths of the
semileptonic decays of B and D mesons. The comparison of our results with the
available experimental data and other approaches is given


title:
Treating the Lifetimes of Charm and Beauty Hadrons with QCD Plus a Bit
  More!

abstract:
  The heavy quark expansion implemented through an operator product expansion
provides us with a treatment of inclusive decays of beauty and charm hadrons
that is genuinely derived from QCD,though it requires one additional
assumption, namely that of 'local' quark-hadron duality. Subtleties in the
application of factorization to hadronic expectation values are pointed out.
The observed pattern in the charm lifetime ratios is reproduced in a
semi-quantitative manner. The ratio $\tau (\Lambda _b)/\tau (B_d)$ cannot be
pushed significantly below 0.9 -- unless one invokes a new hitherto unknown
paradigm for evaluating baryonic matrix elements. One confidently predicts
$\tau (B^-)$ to exceed $\tau (B_d)$ by several percent only. Failure of those
predictions would force us to pay a hefty theoretical price, namely ultimately
to abandon local duality as a practical concept.


title: Minijet and Transverse Energy Production in the BFKL Regime

abstract:
  Minijet production in hadronic and nuclear collisions through a BFKL pomeron
ladder is studied for the energies of the future LHC heavy-ion collisions. We
use unintegrated gluon densities compatible with the small-$x$ increase of
parton distributions observed at HERA. We show that at LHC energies the BFKL
minijet and transverse energy production is at most of the same order of
magnitude as that in the collinear factorization approach.


title: The proper identification of the heavy baryons

abstract:
  The new designation of heavy baryons proposed by Falk (hep-ph/9603389) is
shown to violate minimal symmetry sum rules.


title:
A Non-supersymmetric Interpretation of the CDF e+e-\gamma\gamma +
  missing E_T Event

abstract:
  The $\eegg$ event reported recently by the CDF Collaboration has been
interpreted as a signal of supersymmetry in several recent papers. In this
article, we report on an alternative non-supersymmetric interpretation of the
event using an extension of the standard model which contains new physics at
the electroweak scale that does not effect the existing precision electroweak
data. We extend the standard model by including an extra sequential generation
of fermions, heavy right-handed neutrinos for all generations and an extra
singly charged SU(2)-singlet Higgs boson. We discuss possible ways to
discriminate this from the standard supersymemtric interpretations.


title: Cosmology and Astroparticles

abstract:
  Talks given at the V Taller de Particulas y Campos (V-TPyC) and V Taller
Latinoam. de Fenomenologia de las Interac. Fundam. (V-TLFIF), Puebla, Mexico,
10/30 - 11/3 1995. These lectures are devoted to elementary particle physicists
and assume the reader has very little or no knowledge of cosmology and
astrophysics. After a brief historical introduction to the development of
modern cosmology and astro-particles in which the Hot Big Bang model is
defined, the Robertson-Walker metric and the dynamics of the
Friedmann-Robertson-Walker cosmology are discussed in section 2. In section 3
the main observational features of the Universe are reviewed, including a
description of our neighbourhood, homogeneity and isotropy, the cosmic
background radiation, the expansion, the age and the matter content of the
Universe. A brief account of the thermal history of the Universe follows in
section 4, and relic abundances are discussed in section 5. Section 6 is
devoted to primordial nucleosynthesis, section 7 to structure formation in the
Universe and section 8 to the possibility of detection of the dark matter in
the halo of our galaxy.


title: Systematics of quarkonium production

abstract:
  Quarkonium production in high-energy reactions is found to exhibit a
behaviour more universal than that expected from velocity scaling. Total rates
of quarkonia produced in hadronic interactions as well as Feynman-x and
transverse momentum distributions can be described over the full range of
accessible energies (15 < sqrt{s} < 1800 GeV) by two-stage processes. The
quarkonium production cross section factors into a process-dependent
short-distance part and a single long-distance matrix element. The first part
describing the production of a free quark--antiquark pair is the perturbatively
calculated subthreshold cross section. The non-perturbative factor turns out to
be universal, giving the model great predictive power. Furthermore we estimate
the fraction of the heavy-quark cross section leading to quarkonium for both
the charm and bottom systems. Finally, we comment on quarkonium
photoproduction.


title: A sterile neutrino scenario constrained by experiments and cosmology

abstract:
  We discuss a model in which three active and one sterile neutrino account for
the solar, the atmospheric and the LSND neutrino anomalies. It is shown that if
$N_\nu<4$ then these and other experiments and big bang nucleosynthesis
constrain all the mixing angles severely, and allow only the small-angle MSW
solution. If these neutrinos are of Majorana type, then negative results of
neutrinoless double beta decay experiments imply that the total mass of
neutrinos is not sufficient to account for all the hot dark matter components.


title: More varieties of hybrid inflation

abstract:
  It is pointed out that hybrid inflation can be implemented with the inflaton
field rolling away from the origin instead of towards it. This `inverted'
hybrid inflation has a spectral index $ n < 1 $, in contrast with ordinary
hybrid inflation which has $ n \gtrsim 1 $, so a measured value of $n$
substantially different from 1 would distinguish the two. Other generalisations
of hybrid inflation are also considered.


title:
Experimental Information on the Mass Composition of Primary Cosmic Rays
  Using the KASCADE array

abstract:
  A procedure is proposed to extract experimental information about the primary
cosmic Ray composition from the data taken with the KASCADE setup.


title: The Minimal Supersymmetric Standard Model (MSSM)

abstract:
  The structure of the MSSM is reviewed. We first motivate the particle content
of the theory by examining the quantum numbers of the known standard model
particles and by the requirement of anomaly cancellation. Once the particle
content is fixed we can write down the most general renormalizable
superpotential. However such a superpotential will contain terms breaking
lepton and baryon number which leads us to the concept of R-parity
conservation. The question of supersymmetry breaking is discussed next. We list
the possible soft breaking terms. However the Lagrangian involving the most
general soft breaking terms is phenomenologically intractable because of the
appearance of the many new parameters. It also leads to some unacceptable
predictions. To reduce the number of parameters we restrict ourself to the case
with universal soft breaking terms at the GUT scale. We motivate the need for
universal soft breaking terms by the apparent unification of gauge couplings in
the MSSM and by the absence of flavor changing neutral currents. Then we
discuss radiative electroweak symmetry breaking. Radiative breaking arises
because the one loop corrections involving the large top Yukawa coupling change
the sign of the soft breaking mass parameter of the up-type Higgs doublet, this
way introducing a nontrivial minimum in the Higgs potential. Finally we give an
overview of the possible mixings in the MSSM and enumerate the physical (mass
eigenstate) fields together with the mass matrices.


title: ALEPH Four-Jet Excess, $R_b$ and $R-$Parity Violation

abstract:
  We review briefly the indications for some relatively light superpartners
based on the ~$R_b$ ~anomaly and discuss the dependence of the potential
increase in $R_b$ on the assumption about ~$R-$parity (non)conservation. We
point out that the exotic 4-jet events reported by ALEPH may constitute a
signal for supersymmetry with such a light spectrum and with explicitly broken
$R-$parity. A parton level simulation shows that production of a pair of light
charginos with their subsequent baryon-number violating decays (either through
a stop or through a neutralino) could possibly give rise to this excess. The
decay $\chi^- \ra \tilde{t}_R^\ast b \ra d s b$ with $m_{\chi^-_1} \sim 60
\gev$ and $m_{\tilde t} \sim 52 \gev$ leads to signatures very close to the
experimental observations.


title: Preheating, Supersymmetry Breaking and Baryogenesis

abstract:
  Fluctuations of scalar fields produced at the stage of preheating after
inflation are so large that they can break supersymmetry much stronger than
inflation itself. These fluctuations may lead to symmetry restoration along
flat directions of the effective potential even in the theories where the usual
high temperature corrections are exponentially suppressed. Our results show
that nonthermal phase transitions after preheating may play a crucial role in
the generation of the primordial baryon asymmetry by the Affleck-Dine
mechanism. In particular, the baryon asymmetry may be generated at the very
early stage of the evolution of the Universe, at the preheating era, and not
when the Hubble parameter becomes of order the gravitino mass.


title:
Studying a Strongly Interacting Electroweak Sector via Longitudinal
  Gauge Boson Scattering at a Muon Collider

abstract:
  We discuss the excellent prospects for a detailed study of a strongly
interacting electroweak sector at a muon collider with c.m. energy $\rts\sim
4\tev$. For expected luminosity of $L=200-1000\fbi$ per year, $\mup\mum$ and
$\mup\mup$ (or $\mum\mum$) collisions can be used to study longitudinal
$\wp\wm$ and $\wp\wp$ (or $\wm\wm$) scattering with considerable precision. In
particular, detailed measurements of the distribution in the $VV$ pair masses
($V=\wpm,Z$) will be possible. The shape and magnitude of these distributions
will provide a powerful tool for determining the nature of strong gauge boson
interactions. Event rates will be large enough that projection techniques can
be used to directly isolate final states with different polarizations of the
$V$'s and verify that the strong interaction cross section excess is mainly in
the longitudinal-longitudinal mode.


title:
Signatures of Baryon non-conserving Yukawa couplings in a supersymmetric
  theory

abstract:
  Renormalization effects of large baryon-nonconserving Yukawa couplings
$\lambda^{\prime\prime}_{ijk} \overline{U_i} \overline{D_j} \overline{D_k}$
lower the right handed squark masses keeping the left-handed squark masses
virtually untouched at the lowest order. At low energy they enhance the
mass-splitting between left and right handed squarks of the same generation as
well as intergenerational mass splitting among squarks, potentially detectable
in future colliders or in rare decays. The predicted mass of the lightest stop
squark becomes lower than the experimental bound for larger ranges of parameter
space than that of the Baryon-conserving case, hence, further constraining the
parameter space of a supersymmetric theory when baryon violation is included.


title: Spin Correlations in Top-Quark Pair Production at $e^+e^-$ Colliders

abstract:
  We show that top-quark pairs are produced in an essentially unique spin
configuration in polarized $e^+e^-$ colliders at all energies above the
threshold region. Since the directions of the electroweak decay products of
polarized top-quarks are strongly correlated to the top-quark spin axis, this
unique spin configuration leads to a distinctive topology for top-quark pair
events which can be used to constrain anomalous couplings to the top-quark. A
significant interference effect between the {\it longitudinal} and {\it
transverse} W-bosons in the decay of polarized top-quarks is also discussed.
These results are obtained at leading order in perturbation theory but
radiative corrections are expected to be small.


title:
How to Observe the Interference Effects of Top quark polarizations at
  Tevatron

abstract:
  Using a simple analytic expression for $q \bar{q}, g g \rightarrow t \bar{t}
\rightarrow b W^+ \bar{b} W^- \rightarrow b \bar{l} \nu_l \bar{b} l'
\bar{\nu_{l'}}$ with the interference effects due to the polarizations of the
$t$ and $\bar{t}$, we demonstrate how the effects can be measured at Tevatron
at $3\sigma$ level.


title: Calculation of the Cross Section for Top Quark Production

abstract:
  We summarize calculations of the cross section for top quark production at
hadron colliders within the context of perturbative quantum chromodynamics,
including resummation of the effects of initial-state soft gluon radiation to
all orders in the strong coupling strength. In our approach we resum the
universal leading-logarithm contributions, and we restrict the calculation to
the region of phase space that is demonstrably perturbative. We compare our
approach with other methods. We present predictions of the physical cross
section as a function of the top quark mass in proton-antiproton reactions at
center-of-mass energies of 1.8 and 2.0 TeV, and we discuss estimated
uncertainties.


title: D^0-\bar{D}^0 Mixing and CP Violation in Neutral D-meson Decays

abstract:
  D^0-\bar{D}^0 mixing at the detectable level or significant CP violation in
the charm system may strongly signify the existence of new physics. In view of
the large discovery potential associated with the fixed target experiments, the
B-meson factories and the \tau-charm factories, we make a further study of the
phenomenology of D^0-\bar{D}^0 mixing and CP violation in neutral $D$-meson
decays. The generic formulas for the time-dependent and time-integrated decay
rates of both coherent and incoherent D^0\bar{D}^0 events are derived, and
their approximate expressions up to the second order of the mixing parameters
x_D and y_D are presented. Explicitly we discuss D^0-\bar{D}^0 mixing and
various CP-violating signals in neutral D decays to the semileptonic final
states, the hadronic CP eigenstates, the hadronic non-CP eigenstates and the
CP-forbidden states. A few non-trivial approaches to the separate determination
of x_D and y_D and to the demonstration of direct and indirect CP asymmetries
in the charm sector are suggested.


title: Hybrid Inflation from Supergravity D Terms

abstract:
  We argue that the mass of the inflaton can be much smaller than the Hubble
constant in supergravity models in which inflation is driven by D--terms and
not F--terms. We investigate a supergravity toy model which leads to hybrid
inflation due to an anomalous D--term. We show that the slow--roll condition
can be satisfied and the correct magnitude for density perturbations can be
obtained for some choice of model parameters. The kind of model considered can
naturally arise in some string derived supergravity models.


title: CP Violation in Hyperon Decays

abstract:
  The CP properties in hyperon decays are briefly reviewed. We discuss the
general phenomenology and define CP odd observables in hyperon decays. With
these observables, we discuss the predictions of some models and their
observational potential.


title: Small-Angle Electron-Positron Scattering

abstract:
  We consider small--angle electron--positron scattering in Quantum
Electrodynamics. Leading logarithmic contributions to the cross--section are
explicitly calculated to three loop. Next--to--leading terms are exactly
computed to two loop. All the radiative corrections due to photons as well as
pair production are taken into account. The impact of newly evaluated
next-to-leading and higher order leading corrections is discussed and numerical
results are explicitly given. The results obtained are generally valid for high
and low energy $e^+e^-$ colliders. At LEP and SLC these results can be used to
reduce the uncertainty on the cross--section below the per mille level.
  PACS numbers 12.15.Lk, 12.20.--m, 12.20.Ds, 13.40.--f


title: Simple Physical Approach to Thermal Cutting Rules

abstract:
  A first-principles derivation is given of the imaginary part of a Green's
function in real-time thermal field theory. The analysis and its conclusions
are simpler than in the usual circled-vertex formalism. The relationship to
Cutkosky-like cutting rules is explained.


title: Non Abelian $q\bar{q}$ contributions to small-$x$ anomalous dimensions

abstract:
  By using $\k$-factorization, we derive resummation formulas for the
non-abelian $q\bar{q}$ contributions to both heavy flavour production by gluon
fusion, and to the next-to-leading BFKL kernel. By combining this result with
previous ones by Fadin et al. on the virtual terms, we also compute in closed
form the complete $q\bar{q}$ contribution to the gluon anomalous dimension in
the $Q_0$-scheme. We find that $q\bar{q}$ resummation effects are important for
heavy flavour production, but are instead small in the anomalous dimension
eigenvalues, because of a cancellation between abelian and non abelian
contributions.


title: Velocities of pulsars and neutrino oscillations

abstract:
  Neutrino oscillations, biased by the magnetic field, alter the shape of the
neutrinosphere in a cooling protoneutron star emerging from the supernova
collapse. The resulting anisotropy in the momentum of outgoing neutrinos can be
the origin of the observed proper motions of pulsars. The connection between
the pulsars velocities and neutrino oscillations results in a prediction for
the tau neutrino mass of order 100 eV.


title:
Gauge Invariant YFS Exponentiation of (Un)stable $W^+W^-$ Production At
  and Beyond LEP2 Energies

abstract:
  We present the theoretical basis and sample Monte Carlo data for the YFS
exponentiated calculation of $e^+e^- \rightarrow W^+ W^- \rightarrow f_1\bar
f'_1 + \bar f_2 f'_2$ at and beyond LEP2 energies, where the left-handed parts
of $f_i$ and $f'_i$ are the respective upper and lower components of an
$SU_{2L}$ doublet, $i=1,2$. The problem of gauge invariance of the radiation
from the unstable charged spin~1 $W^{\pm}$ is solved in an entirely physical
manner. Our formulas are illustrated in a proto-typical YFS Monte Carlo event
generator YFSWW2, wherein both Standard Model and anomalous triple gauge boson
couplings are allowed.


title:
Low-Energy QCD: Chiral Coefficients, UA(1)-Breaking and the Quark-Quark
  Interaction

abstract:
  A detailed investigation of the low-energy chiral expansion is presented
within a model truncation of QCD. The model dependence of the chiral
coefficients is tested for several forms of the quark-quark interaction by
varying the form of the running coupling in the infrared region. Furthermore we
demonstrate how the UA(1)$ anomaly and a mass for the eta' can arise in this
approach.


title: Gauge-Mediated Curvature of the Flat Directions During Preheating

abstract:
  Usually one expectes the inflaton field to be coupled to some gauge-charged
particles allowing for its decay during reheating. Such particles then play a
role of the messengers for the gauge-mediated supersymmetry breaking during and
(shortly) after the inflation and radiatively induce soft masses to all other
$D$-flat directions. We show that during the preheating stage this
gauge-mediated soft masses are typically much greater than the Hubble parameter
during inflation. The dramatic role is played by the supersymmetry (SUSY)
breaking due to the parametric resonance effect, which ensures that the
inflaton predominantly decays into the bosons and not the fermions. Difference
in the Fermi-Bose occupation numbers results in the large gauge-mediated soft
masses, which determine the post-inflationary evolution of the flat directions,
suggesting that nonthermal phase transitions mediated by gauge messengers may
play a crucial role in the Affelck-Dine mechanism for the generation of the
baryon asymmetry.


title: Redundance of $\Delta$-isobar Parameters in Effective Field Theories

abstract:
  It is shown that the off-shell parameters in the interaction Lagrangian of
pions, nucleons, and $\Delta$-isobars are redundant in the framework of
effective field theories. Our results also suggest the necessity of including
the $\Delta$ as an explicit dynamical degree of freedom.


title: Hamiltonian Analysis of the Deep Inelastic Structure Function

abstract:
  We investigate the feasibility of analyzing deep inelastic structure
functions in Hamiltonian formalism by combining the light-front BJL limit of
high energy amplitudes and the Fock space (multi-parton) description of
hadrons. This study is motivated by some of the theoretical questions emerging
from the ongoing nonperturbative/perturbative studies in light-front QCD and
also by current problems in the interface of perturbative/nonperturbative QCD.
In this preliminary study, we address the unpolarized structure function $F_2$.
Our starting point is the expression for the quark structure function as the
Fourier transform of the expectation value of the {\it good component} of a
bilocal current in the target state. By expanding the target state in a set of
multi-particle Fock states, the structure function is expressed as the sum of
squares of multi-parton wavefunctions integrated over independent longitudinal
and transverse parton momenta. Utilizing the fact that the multi-particle Fock
states are connected with each other by the light-front QCD Hamiltonian, we
study questions of cancellation of collinear singularities, factorization of
mass singularities, and the logarithmic scaling violations in the Hamiltonian
picture. In this paper the essential features of the formalism are illustrated
utilizing the calculation of the structure function of a dressed quark and the
evolution of the valence part of the $q {\bar q}$ bound state structure
function up to order $g^2$.


title: Unification of Gauge and Yukawa Couplings without Symmetry

abstract:
  A natural gradual extension of the idea of Grand Unification is to attempt to
relate the gauge and Yukawa couplings; Gauge-Yukawa Unification (GYU). However,
within the framework of renormalizable field theories, there exists no
realistic symmetry that leads to a GYU. Here we propose an approach to GYU
which is based on the principle of the reduction of couplings and finiteness in
supersymmetric Grand Unified Theories. We elucidate how the observed top-bottom
mass hierarchy can be explained in terms of supersymmetric GYU by considering
an example of the $SU(5)$ Finite Unified Theory. It is expected that, when more
accurate measurements of the top and bottom quark masses are available, it will
be possible to discriminate among the various GYU models.


title: Effective lagrangian description of top production and decay

abstract:
  We propose a rather general description of residual New Physics (NP) effects
on the top quark couplings. These effects are described in terms of 20 gauge
invariant $dim=6$ operators involving gauge and Higgs bosons as well as quarks
of the third family. We compute their implications for the $\gamma t\bar t$, $Z
t \bar t$ and $tbW$ vertices and study their observability in the process
$e^-e^+ \to t\bar t$ with $t\to bW \to b\ell^+\nu_\ell$. We present results for
the integrated cross section, the angular distribution and various decay
distribution and polarization asymmetries for NLC energies of $0.5-2~TeV$.
Observability limits are discussed and interpreted in terms of the NP scales
associated to each operator through the unitarity constraints. The general
landscape of the residual NP effects in the heavy quark and bosonic sectors is
also presented.


title: $Zb\bar{b}$ Loop Correction with Charge 2/3 Singlet Quarks

abstract:
  We calculate the non-universal correction to the $Zb\bar{b}$ vertex in a
simple extension of the Standard Model, where a charge $+2/3$ isosinglet quark
is added to the standard spectrum. Comparison is made with other solutions to
$R_b$ (and $R_c$) that demand particles lighter than $M_W$.


title: Directions in High Energy Physics

abstract:
  The future goals of particle physics are classified from a theorist's point
of view. The prospects of mass and mixing angle determination and of the top
quark and Higgs boson discovery are discussed. It is shown that the most
important progress will come from LHC and NLC. These machines should be planned
and developed as quickly as possible.


title: Bosonic Thermal Masses in Supersymmetry

abstract:
  Effective thermal masses of bosonic particles in a plasma play an important
role in many different phenomena. We compute them in general supersymmetric
models at leading order. The origin of different corrections is explicitly
shown for the formulas to be applicable when some particles decouple. The
correct treatment of Boltzmann decoupling in the presence of trilinear
couplings and mass mixing is also discussed. As a relevant example, we present
results for the Minimal Supersymmetric Standard Model.


title: Quantum Subcritical Bubbles

abstract:
  We quantize subcritical bubbles which are formed in the weakly first order
phase transition. We find that the typical size of the thermal fluctuation
reduces in the quantum-statistical physics. We estimate the typical size and
the amplitude of thermal fluctuations near the critical temperature in the
electroweak phase transition using quantum statistical average. Furthermore
based on our study, we give implication on the dynamics of phase transition.


title:
Strange vector form factors of the nucleon in the SU(3) chiral
  quark-soliton model with the proper kaonic cloud

abstract:
  The strange vector form factors are evaluated in the range between $Q^2=0$
and $Q^2=1\ \mbox{GeV}^2$ in the framework of the SU(3) chiral quark-soliton
model (or semi-bosonized SU(3) Nambu-Jona-Lasinio model). The rotational
$1/N_c$ and $m_s$ corrections are taken into account up to linear order. Taking
care of a proper Yukawa-tail of the kaonic cloud, we get $\langle
r^{2}\rangle^{\rm Sachs}_{s}=-0.095\; \mbox{fm}^2$ and $\mu_s = -0.68\;\mu_N$.
The results are compared with several different models.


title:
Regge behaviour and Regge trajectory for ladder graphs in scalar
  $\Phi^3$ field theory

abstract:
  Using the gaussian representation for propagators (which can be proved to be
exact in the infinite number of loops limit) we are able to derive the Regge
behaviour for ladder graphs of $\phi^3$ field theory in a completely new way.
An analytic expression for the Regge trajectory $\alpha (t/m^2)$ is found in
terms of the mean-values of the Feynman $\alpha$-parameters. $\alpha (t/m^2)$
is calculated in the range $- 3.6 < t/m^2 < 0.8$. The intercept $\alpha (0)$
agrees with that obtained from earlier calculations using the Bethe-Salpeter
approach for $\alpha (0) \gsim 0.3$.


title: Color filamentation in ultrarelativistic heavy-ion collisions

abstract:
  We study color fluctuations in the quark-gluon plasma produced at the early
stage of nucleus-nucleus collision at RHIC or LHC. The fluctuating color
current, which flows along the beam, can be very {\it large} due to the strong
anisotropy of the parton momentum distribution. A specific fluctuation, which
splits the parton system into the current filaments parallel to the beam
direction, is argued to grow exponentially. The physical mechanism responsible
for the phenomenon, which is known as a filamentation instability, is
discussed.


title: Diffractive open charm production at HERA

abstract:
  We use perturbative QCD to calculate the cross sections $\sigma^{L,T}$ for
the diffractive production of open charm $(c\overline{c})$ from longitudinally
and transversely polarised photons (of virtuality $Q^2$) incident at high
energy $(\sqrt{s})$ on a proton target. We study both the $Q^2$ and $M^2$
dependence of the cross sections, where $M$ is the invariant mass of the
$c\overline{c}$ pair. Surprisingly, the result for $\sigma^T$, as well as for
$\sigma^L$, is perturbatively stable. We estimate higher-order corrections and
find a sizeable enhancement of the cross sections. The cross sections depend on
the {\it square} of the gluon density $g (x, K^2)$, and we show that the
observation of open charm at the HERA electron-proton collider can act as a
sensitive probe of the gluon distribution for $x = (Q^2 + M^2)/s$ and scale
$K^2 = (m_c^2 + \langle k_T^2 \rangle) (1 + Q^2/M^2)$ where the average quark
transverse momentum squared $\langle k_T^2 \rangle \sim m_c^2$. As compared to
diffractive $J/\psi$ production, open charm has the advantage that it is
independent of the non-perturbative ambiguities arising from the $J/\psi$ wave
function. We estimate the fraction of diffractive events that arise from
$c\overline{c}$ production.