title: Two-loop three-gluon vertex in zero-momentum limit

abstract:
  The two-loop three-gluon vertex is calculated in an arbitrary covariant
gauge, in the limit when one of the external momenta vanishes. The differential
Ward-Slavnov-Taylor (WST) identity related to this limit is discussed, and the
relevant results for the ghost-gluon vertex and two-point functions are
obtained. Together with the differential WST identity, they provide another
independent way for calculating the three-gluon vertex. The renormalization of
the results obtained is also presented.


title:
Threshold Resummation of Soft Gluons in Hadronic Reactions -- An
  Introduction

abstract:
  I discuss the motivation for resummation of the effects of initial-state soft
gluon radiation, to all orders in the strong coupling strength, for processes
in which the near-threshold region in the partonic subenergy is important. I
summarize the method of "perturbative resummation" and its application to the
calculation of the total cross section for top quark production at hadron
colliders. Comments are included on the differences between the treatment of
subleading logarithmic terms in this method and in other approaches.


title:
A model of the composite structure of quarks and leptons with SU(4)
  gauge symmetry

abstract:
  A model in which quarks and leptons consist of three "more elementary"
particles of spin 1/2 is proposed. A gauge field theory with SU(4) symmetry
that corresponds to this model predicts the existence of two new bosons.


title:
TARCER - A Mathematica program for the reduction of two-loop propagator
  integrals

abstract:
  TARCER is an implementation of the recurrence algorithm of O.V. Tarasov for
the reduction of two-loop propagator integrals with arbitrary masses to a small
set of basis integrals. The tensor integral reduction scheme is adapted to
moment integrals emerging in operator matrix element calculations.


title:
Second Order in Mass Ratio Radiative-Recoil Corrections to Hyperfine
  Splitting in Muonium

abstract:
  Radiative-recoil corrections to hyperfine splitting in muonium of orders
$\alpha(Z\alpha)(m/M)^2E_F$ and $(Z^2\alpha)(Z\alpha)(m/M)^2E_F$ are
calculated. These corrections are of the second order in the small
electron-muon mass ratio. An analytic expression $[(-6 \ln2- \frac{3}{4})\alpha
(Z\alpha) - \frac{17}{12} (Z^2 \alpha) (Z\alpha)](\frac{m}{M})^2 E_F$ is
obtained. Numerically the correction is equal to $-0.0351\:\mbox{kHz}$ and is
of the same order of magnitude as the expected accuracy of the current Los
Alamos experiment to measure the hyperfine splitting.


title: Technicolor and the First Muon Collider

abstract:
  The motivations for studying dynamical scenarios of electroweak and flavor
symmetry breaking are reviewed and the latest ideas, especially
topcolor-assisted technicolor, are summarized. Technicolor's observable
low-energy signatures are discussed. The superb energy resolution of the First
Muon Collider may make it possible to resolve the extraordinarily narrow
technihadrons that occur in such models--$\pi_T^0$, $\rho_T^0$, $\omega_T$--and
produce them at very large rates compared to other colliders.


title: New Physics Effects in CP-Violating B Decays

abstract:
  Contributions to B - \bar B mixing from physics beyond the standard model may
be detected from CP-violating asymmetries in B decays. There exists the
possibility of large new contributions that cannot be detected by first
generation experiments because of a discrete ambiguity. Some possible
strategies for resolving this are discussed.


title: Neutrino-Exchange Interactions in 1-, 2-, and 3-Dimensions

abstract:
  We examine several recent calculations of the self-energy of a neutron star
arising from neutrino-exchange. It is shown that the results of Abada, et al.
in 1+1 dimensions have no bearing on a 3-dimensional neutron star, since the
criticality parameter (Gf N)/R^2 is always much smaller than unity in 1+1
dimensions. The calculation of Kiers and Tytgat in 3-dimensions is shown to
disagree with the lowest order 2-body contribution, which is known exactly.
This discrepancy raises the possibility that the description of a neutron star
as a continuous medium may be inappropriate when calculating higher-order
many-body effects. We conclude that none of the recent calculations contradict
the earlier claims that the neutrino-exchange contributions to the self-energy
of a neutron star are unphysically large, when calculated in the standard
model. The implication of this result, that neutrinos must have a non-zero
mass, m > 0.4 eV, remains intact.


title:
Methods in the LO Evolution of Nondiagonal Parton Distributions: The
  DGLAP Case

abstract:
  In this paper, we discuss the algorithms used in the LO evolution program for
nondiagonal parton distributions in the DGLAP region and discuss the stability
of the code. Furthermore, we demonstrate that we can reproduce the case of the
LO diagonal evolution within 0.5% of the original code as developed by the
CTEQ-collaboration.


title: A free action for pions as quark composites

abstract:
  In the framework of an approach to bosonization based on the use of fermionic
composites as fundamental variables, a quadratic action in even Grassmann
variables with the quantum numbers of the pions has been constructed. It
includes the sigma-field in order to be invariant under SU(2)_L times SU(2)]_R
transformations over the quarks. This action exhibits the Goldstone phenomenon
reducing its symmetry to the O(3) isospin invariance. A squared mass for the
pions is generated according to PCAC. The model has been investigated in the
Stratonovitch-Hubbard representation, in which form it is reminiscent of the
Gell-Mann-Levy model. By the saddle point method a renormalizable expansion in
inverse powers of the index of nilpotency of the mesonic fields (which is 24),
is generated. The way it might be used in a new perturbative approach to QCD is
outlined.


title:
Top Quark Loop Corrections to the Neutral Higgs Boson Production at the
  Fermilab Tevatron

abstract:
  We calculate the $O(\alpha m_t^2/m^2_W)$ corrections arising from diagrams
involving the top-quark loops to the light neutral Higgs boson production via
$q\bar q'\to WH$ at the Fermilab Tevatron in both the standard model and the
minimal supersymmetric model. In contrast to the QCD correction which increases
the tree-level cross section, the corrections imply a few percent reduction in
the production cross section relative to the tree-leve results.


title: Gauge and Yukawa Unification with Broken R-Parity

abstract:
  We study gauge and Yukawa coupling unification in the simplest extension of
the Minimal Supersymmetric Standard Model (MSSM) which incorporates R-Parity
violation through a bilinear superpotential term. Contrary to what happens in
the MSSM, we show that bottom-tau unification at the scale M_GUT where the
gauge couplings unify can be achieved for any value of tan(beta) by choosing
appropriately the sneutrino vacuum expectation value. In addition, we show that
bottom-tau-top unification occurs in a slightly wider tan(beta) range than in
the MSSM.


title:
Inelastic diffraction and color-singlet gluon-clusters in high-energy
  hadron-hadron and lepton-hadron collisions

abstract:
  It is proposed, that ``the colorless objects'' which manifest themselves in
large-rapidity-gap events are color-singlet gluon-clusters due to
self-organized criticality (SOC), and that optical-geometrical concepts and
methods are useful in examing the space-time properties of such objects. A
simple analytical expression for the $t$-dependence of the inelastic single
diffractive cross section $d\sigma/dt$ ($t$ is the four-momentum transfer
squared) is derived. Comparison with the existing data and predictions for
future experiments are presented. The main differences and similarities between
the SOC-approach and the ``Partons in the Pomeron (Pomeron and
Reggeon)''-approach are discussed.


title: Equation of State, Flow, Fluctuations and $J/\psi$ suppression

abstract:
  Radial flow observed at AGS/SPS energies is very strong, with collective
velocities of matter reaching about 0.5c for central collisions of the heaviest
ions. The lattice-based Equation of State (EOS) is however rather soft, due to
the QCD phase transition. We show that both statements are consistent only if
proper kinetic-based treatment of the freeze-out is made. In fact chemical and
thermal freeze-out happen at quite different conditions, especially at SPS.
Event-by-event fluctuations can shed new light on this problem. We also propose
new model of "anomalous" $J/\psi$ suppression found for PbPb collisions,
related it to prolonged lifetime of dense matter due the "softest point" of the
EOS.


title: Parity violating asymmetries at future lepton colliders

abstract:
  Parity violating left-right scattering asymmetries at future high energy e+e-
and e-e- colliders are examined. The utility of two polarized beams for
precision measurements is pointed out. Sensitivity to ``new'' short-distance
physics is briefly discussed. Electroweak radiative corrections due to the
running of sin^2(theta_W)(q^2) are exhibited.


title: SUSY Before the Next Lepton Collider

abstract:
  After a brief review of the Minimal Supersymmetric Standard Model (MSSM) and
specifically the Minimal Supergravity Model (SUGRA), the prospects for
discovering and studying SUSY at the CERN Large Hadron Collider are reviewed.
The possible role for a future Lepton Collider --- whether $\mu^+\mu^-$ or
$e^+e^-$ --- is also discussed.


title: Sleptons at a First Muon Collider

abstract:
  Signatures for sleptons, which have been extensively studied for the Next
Linear Collider, are reexamined taking into account some of the different
features of a First Muon Collider.


title:
Top Quark Pair Production at Threshold: Complete Next-to-next-to-leading
  Order Relativistic Corrections

abstract:
  The complete next-to-next-to-leading order (i.e. $O(v^2)$, $O(v \alpha_s)$
and $O(\alpha_s^2)$) relativistic corrections to the total photon mediated
$t\bar t$ production cross section at threshold are presented in the framework
of nonrelativistic quantum chromodynamics. The results are obtained using
semi-analytic methods and ``direct matching''. The size of the
next-to-next-to-leading order relativistic corrections is found to be
comparable to the size of the next-to-leading order ones.


title:
Two Particle Physics Models With Spontaneous CP Violation From Gauge
  Theory On Discrete Group

abstract:
  Based on the differential calculus and the gauge theory on discrete groups,
we reconstruct two physics models with spontaneous CP violation: (1) The
Georgi-Glashow-Lee model with two Higgs triplets; (2) The Weinberg-Salam-Branco
model with three Higgs doublets and the natural flavor conservation (NFC). We
focus on the Lagrangian terms containing the Higgs particles and show that with
an appropriate choice of the discrete groups, we can obtain the physically
meaningful Yukawa couplings and the Higgs potentials which lead to the
spontaneous CP violation consequently.


title:
Two mechanisms for the elimination of pinch singularities in out of
  equilibrium thermal field theories

abstract:
  We analyze ill-defined pinch singularities characteristic of out of
equilibrium thermal field theories. We identify two mechanisms that eliminate
pinching even at the single self-energy insertion approximation to the
propagator: the first is based on the vanishing of phase space at the singular
point (threshold effect). It is effective in QED with a massive electron and a
massless photon. In massless QCD, this mechanism fails, but the pinches cancel
owing to the second mechanism, i.e., owing to the spinor/tensor structure of
the single self-energy insertion contribution to the propagator. The
constraints imposed on distribution functions are very reasonable.


title: NLO QCD Corrections and Triple Gauge Boson Vertices at the NLC

abstract:
  We study NLO QCD corrections as relevant to hadronic W decay in W pair
production at a future 500 GeV electron-positron linac, with particular
emphasis on the determination of triple gauge boson vertices. We find that hard
gluon bremstrahlung may mimic signatures of anomalous triple gauge boson
vertices in certain distributions. The size of these effects can strongly
depend on the polarisation of the initial electron positron beams.


title:
Soliton Solutions of the $\sigma$ Model and the Disoriented Chiral
  Condensates

abstract:
  We derive travelling soliton solutions of the $\sigma$ model, relevant for
the description of dynamics of pions, in the high-energy, heavy-ion collisions.
These extended objects are analogs of Ne$\grave{e}$l and Bloch type defects in
ferromagnetic systems and could possibly describe the disoriented chiral
condensates. It is shown that these solutions are metastable and can naturally
produce an asymmetry between $\pi^0 $ and $ \pi^+$, $\pi^- $ mesons in the
soft-pion emissions from heavy-ion collisons.


title: $a \to e^+ e^-$ decay in a model with induced coupling to leptons

abstract:
  The process of electron-positron pair production by axion propagating in an
external magnetic field is investigated in a model with only induced axion
coupling to leptons. Contributions of the lowest and higher Landau levels are
analyzed. The results we have obtained demonstrate a strong catalyzing
influence of the field.


title:
A Model Independent Analysis of LEP and SLD Data on Z-Decays; is the
  Standard Model Confirmed?

abstract:
  A model independent analysis has been performed on the LEP and SLD data on Z
decays. Using only very weak theoretical assumptions, the effective vector and
axial-vector couplings of leptons, c quarks and b quarks have been extracted.
Although the lepton and c quark couplings agree well with Standard Model
predictions, those of the b quark show deviations of more than three standard
deviations. The effect is mainly in the right-handed b quark coupling, the
left-handed coupling being consistent (at the 2$\sigma$ level) with the
Standard Model prediction. The probability that the observed deviations of all
the measured effective couplings are statistical fluctuations from lepton
universality and the Standard Model is estimated to be 0.9%. The estimated
probability that the deviations in the leptonic and b quark couplings alone are
a fluctuation is 0.18%. A thorough discussion is made of the internal
consistency of the different measurements contributing to the average values
$A_l$ and $A_b$ used to extract the b quark couplings, as well as possible
sources of systematic error that may not, hitherto, have been taken into
account. Excluding \tpol~ measurements, which show internal inconsistencies,
from the averages increases the deviations of the extracted b quark couplings
from the Standard Model predictions to the four standard deviation level.


title:
Wick's Theorem for non-symmetric normal ordered products and
  contractions

abstract:
  We consider arbitrary splits of field operators into two parts, and use the
corresponding definition of normal ordering introduced by Evans and Steer. In
this case the normal ordered products and contractions have none of the special
symmetry properties assumed in existing proofs of Wick's theorem. Despite this,
we prove that Wick's theorem still holds in its usual form as long as the
contraction is a c-number. Wick's theorem is thus shown to be much more general
than existing derivations suggest, and we discuss possible simplifying
applications of this result.


title: Bound states and resonances in the scalar sector of the MSSM

abstract:
  The trilinear couplings of squarks and sleptons to the Higgs bosons can give
rise to a spectrum of bound states with exotic quantum numbers, for example,
those of a leptoquark.


title:
Impacts on searching for signatures of new physics from $K^+ \to \pi^+
  \nu \bar{\nu}$ decay

abstract:
  We study impacts on new physics search from the rare decay $K^+ \to \pi^+ \nu
\bar{\nu}$. In a certain class of new physics models, the extra contributions
to FCNC processes can be parametrized by its ratio to the standard model (SM)
contribution with the common CKM factors. The ratio $R_1$ has been used in the
analysis of $\xd$ and $\epsilon_K$ parameters. In the above class of models,
the $K^+ \to \pi^+ \nu \bar{\nu}$ decay amplitude can be parametrized by the
ratio $R_2$. Then the experimentally allowed region for new physics
contributions can be given in terms of $R_1,R_2$ and the CP violating phase
$\delta$ of the CKM matrix. Constraints on $R_1$ and $\cosd$ are obtained by
taking account of current experimental data and theoretical uncertainties on
$\bbbar$ and $\kkbar$ mixings. We study impacts of future improved measurements
by using $(R_1, R_2, \cosd)$ basis. We discuss contributions in the minimal
supersymmetric SM and the two Higgs doublet model as examples.


title: Higgs Boson and Z Physics at the First Muon Collider

abstract:
  The potential for the Higgs boson and Z-pole physics at the first muon
collider is summarized, based on the discussions at the ``Workshop on the
Physics at the First Muon Collider and at the Front End of a Muon Collider'' .


title:
An Algorithm for Selecting QGP Candidate Events from Relativistic Heavy
  Ion Collision Data

abstract:
  The formation of quark-gluon plasma (QGP) in relativistic heavy ion
collision, is expected to be accompanied by a background of ordinary collision
events without phase transition. In this short note an algorithm is proposed to
select the QGP candidate events from the whole event sample. This algorithm is
based on a simple geometrical consideration together with some ordinary QGP
signal, e.g. the increasing of $K/\pi$ ratio. The efficiency of this algorithm
in raising the 'signal/noise ratio' of QGP events in the selected sub-sample is
shown explicitly by using Monte-Carlo simulation.


title: Family Universal Anomalous U(1) in Realistic Superstring Derived Models

abstract:
  An important issue in supersymmetry phenomenology is the suppression of
squarks contributions to Flavor Changing Neutral Currents (FCNC). Recently it
was noted that in some free fermionic three generation models the anomalous
U(1) is family universal. It was further shown that if the $D$--term of the
$U(1)_A$ is the dominant source of supersymmetry breaking, the squark masses
are indeed approximately degenerate. In this paper I discuss the properties of
the superstring models that give rise to the flavor universal anomalous U(1).
The root cause for the universal $U(1)_A$ is the cyclic permutation symmetry,
the characteristic property of the $Z_2\times Z_2$ orbifold compactification,
realized in the free fermionic models by the NAHE set of boundary condition
basis vectors. The properties of the three generation models that preserve this
cyclic permutation symmetry in the flavor charges are discussed. The cyclic
permutation symmetry of the $Z_2\times Z_2$ orbifold compactification is
proposed to be the characteristic property, of phenomenological interest, that
distinguishes it from other classes of superstring compactifications.


title: Chargino mass determination at a muon collider

abstract:
  We analyze the prospects at a muon collider for measuring chargino masses in
the $\mu^+\mu^-\to \tilde{\chi}^+\tilde{\chi}^-$ process in the threshold
region. We find that for the lighter chargino of a mass $100-200$ GeV, a
measurement better than $50-300$ MeV should be possible with 50 fb$^{-1}$
integrated luminosity. The accuracy obtained here is better than with other
techniques or at other facilities. The muon sneutrino mass, which enters
through the $\tilde{\nu}_\mu$ exchange diagram, can also be simultaneously
measured to a few GeV if it is not too heavy.


title: Approximate CP in Supersymmetric Models

abstract:
  We construct phenomenologically viable supersymmetric models where CP is an
approximate symmetry. The full high energy theory has exact CP and horizontal
symmetries that are spontaneously broken with a naturally induced hierarchy of
scales, $\Lambda_{CP}\ll\Lambda_H$. Consequently, the effective low energy
theory, that is the supersymmetric Standard Model, has CP broken explicitly but
by a small parameter. The $\epsilon_K$ parameter is accounted for by
supersymmetric contributions. The predictions for other CP violating
observables are very different from the Standard Model. In particular, CP
violating effects in neutral B decays into final CP eigenstates such as
$B\ra\psi K_S$ and in $K\ra\pi\nu\bar\nu$ decays are very small.


title:
Quark Masses, B-parameters, and CP violation parameters $\epsilon$ and
  $\epsilon'/\epsilon$

abstract:
  After a brief introduction to lattice QCD, I summarize the results for the
light quark masses and the bag parameters $B_K$, $B_6^{1/2}$, and $B_8^{3/2}$.
The implications of these results for the standard model estimates of CP
violation parameters $\epsilon$ and $\epsilon'/\epsilon$ are also discussed.


title: Comment on "Suppression of piNN* Coupling and Chiral Symmetry"

abstract:
  Jido, Oka and Hosaka have shown that the p-slash gamma_5 piece of the
pion-to-vacuum correlator of two baryon interpolating fields vanishes in the
soft-pion limit, as a consequence of chiral transformation properties of those
fields. This is a statement about the particular combination of pion-baryon
couplings and subtraction terms that corresponds to the chosen interpolating
fields. It does not imply that the physical piNN* coupling of the N(1535) is
suppressed.


title: High-Energy Polarimetry at RHIC

abstract:
  We compare a few types of high energy reactions which seem to be practical
for polarimetry at RHIC. Coulomb-nuclear interference (CNI) in pp elastic
scattering leads to a nearly energy-independent left-right asymmetry A_N(t) at
small t. The systematical uncertainty of this method is evaluated to be ~ 10%.
The CNI in proton-nucleus elastic scattering is predicted to result in larger
values of A_N(t) and occurs at larger momentum transfer than in pp elastic
scattering. This energy independent asymmetry can be used for the polarimetry.
As an absolute polarimeter one can use elastic pp scattering on a fixed target
at large |t| ~ 1 - 1.5 GeV^2, where A_N(t) is reasonably large and nearly
energy independent. Although it cannot be reliably calculated, one can
calibrate the polarimeter by measuring the polarisation of the recoil protons.


title: QCD Sum-Rule Consistency of Lowest-Lying Quark Scalar Resonances

abstract:
  We investigate lowest-lying scalar meson properties predicted from QCD
Laplace sum rules based upon isovector and isoscalar non-strange $\bar{q}q$
currents. The hadronic content of these sum rules incorporates deviations from
the narrow resonance approximation anticipated from physical resonance widths.
The field theoretical content of these sum rules incorporates
purely-perturbative QCD contributions to three-loop order, the direct
single-instanton contribution in the instanton liquid model, and leading
contributions from QCD-vacuum condensates. In the isovector channel, the
results we obtain are compatible with a$_0$(1450) being the lowest-lying
$q\bar{q}$ resonance, and are indicative of a non-$q\bar{q}$ interpretation for
a$_0$(980). In the isoscalar channel, the results we obtain are compatible with
the lowest lying $q\bar{q}$ resonance being f$_0$(980) or a state somewhat
lighter than f$_0$(980) whose width is less than half of its mass. The dilaton
scenario for such a narrower $\sigma$-resonance is discussed in detail, and is
found compatible with sum rule predictions for the resonance coupling only if
the anomalous gluon-field portion of $\Theta_\mu^\mu$ dominates the matrix
element $<\sigma|\Theta_\mu^\mu|0>$. A linear sigma-model interpretation of the
lowest-lying resonance's coupling, when compared to the coupling predicted by
sum rules, is indicative of a renormalization-group invariant light-quark mass
between 4 and 6 MeV.


title: Supersymmetric Partners of Oblique Corrections

abstract:
  We discuss the violation of the equality of the gauge coupling and gaugino
coupling in the presence of soft supersymmetry breaking. Although this is a
hard supersymmetry breaking effect, there are finite contributions to this
difference which can be determined as a function of the soft supersymmetry
breaking masses. The largest sources of this difference are the "super-oblique"
corrections, which can be enhanced by a multiplicity factor and a logarithm of
the soft supersymmetry breaking mass. This is to be contrasted to standard
oblique corrections to the electroweak sector which decouple for large
supersymmetry breaking. We show that these parameters can be relatively large,
particularly in models of supersymmetry breaking motivated by solving the
supersymmetric flavor problem. We also perform a detailed study of the
non-oblique corrections for the example of squark decay. We find that they can
be significant, and should be accounted for in the theoretical prediction.


title: Searching for Low-Energy Supersymmetry

abstract:
  A review of supersymmetry theory and phenomenology is presented. Topics
discussed include: gravity-mediated (SUGRA) and gauge-mediated (GMSB)
supersymmetry breaking models; an overview of non-universal
soft-supersymmetry-breaking masses and the resulting experimental implications;
the phenomenology of and constraints on the possibility that a massive gluino
is the lightest supersymmetric particle; current status of the phenomenology of
the Higgs bosons of the minimal and next-to-minimal supersymmetric models; and,
the signals for GMSB and/or R-parity-violating models coming from delayed
decays of the lightest supersymmetric partner of the Standard Model particles.


title: Chiral Corrections to Vector Meson Decay Constants

abstract:
  We calculate the leading quark mass corrections of order $m_q\log(m_q)$,
$m_q$ and $m_q^{3/2}$ to the vector meson decay constants within Heavy Vector
Meson Chiral Perturbation Theory. We discuss the issue of electromagnetic gauge
invariance and the heavy mass expansion. Reasonably good fits to the observed
decay constants are obtained.


title: QCD Potential and ttbar Threshold Cross Section --- Status Report ---

abstract:
  We include the full second-order corrections to the static QCD potential in
the analysis of the ttbar threshold cross section. Then we examine the
difference between the results obtained in the momentum-space approach and in
the coordinate-space approach, which was found recently. Contrary to our
expectation, the reduction of the difference by the inclusion of the
second-order corrections is very small. There still remains a non-negligible
deviation, which originates from the difference in the construction of the
potentials in the two spaces. We scrutinize this problem. In particular, we
estimate our present theoretical uncertainty of the ttbar threshold cross
section at the peak to be at least 6% within perturbative QCD.


title: Factorization, charming penguins, and all that

abstract:
  We discuss few selected topics related to the calculation of hadronic
amplitudes relevant for two-body non-leptonic B decays.


title: Perturbative QCD Analysis of B to pi and B to rho Transitions

abstract:
  We calculate the form factors of $B\to\pi$ and $B\to\rho$ heavy to light
transition matrix elements by using the factorization formalism of perturbative
QCD. We obtain them at $q^2=0$ and show their dependences on the parameter
$\epsilon$ of the B meson distribution amplitude. We also obtain the form
factors as functions of $q^2$ in the region $0\le q^2 \le M_B^2/2$. The
relations among the form factors are found in the limit of $m_\pi /M_B=0$,
$m_\rho /M_B=0$, ${M_b/M_B}=1$ and $(1-x)<<1$.


title: Bounds on the Standard Higgs Boson

abstract:
  We review the status of precision electroweak physics with particular
emphasis on the extraction of the Higgs boson mass. Global fit results depend
strongly on the used value for the hadronic contribution to alpha(M_Z). We
emphasize, however, that the general tendency for a light Higgs persists when
using any of the recently obtained values for alpha(M_Z), and is also less
dependent on deviating observables such as A_LR than in the past.


title: Prolonged Decoupling

abstract:
  We discuss decay of unstable particles and pair annihilation of stable heavy
particles that occur in the cosmic medium, from the point of the fundamental
microscopic theory. A fully quantum mechanical treatment shows that the effect
of thermal environment on these processes cannot be described in terms of
quantities on the mass shell alone, thus requiring an extention of the
Boltzmann-like equation. The off-shell effect tends to prolong physical
processes that take place subsequent to the decay.


title: Studies of polarized parton distributions at RHIC

abstract:
  We discuss our studies of polarized parton distributions which are related to
the RHIC-Spin project. First, the parametrization of unpolarized parton
distributions is explained as an introduction to general audience. Second,
activities of the RHIC-Spin-J working group are reported. In particular,
preliminary results are shown on the parametrization of polarized parton
distributions. Third, we discuss numerical solution of the DGLAP Q^2 evolution
equations for longitudinally polarized and transversity distributions. An
efficient and accurate computer program is important for analyzing future RHIC
experimental data.


title: The Effective Weak Mixing Angle in the MSSM

abstract:
  The predictions of the MSSM are discussed in the light of recent LEP and SLD
precision data. The full supersymmetric one loop corrections to the effective
weak mixing angle, experimentally determined in LEP and SLD experiments, are
considered. It is demonstrated, both analytically and numerically, that,
potentially dangerous, large logarithmic sparticle corrections are cancelled.
The relative difference factor \Delta k between the mixing angle defined as a
ratio of couplings and the experimentally obtained angle is discussed. It is
found that \Delta k is dominated by the oblique corrections, while the
non-oblique overall supersymmetric EW and SQCD corrections are negligible. The
comparison of the MSSM with radiative electroweak symmetry breaking to the
LEP+SLD precision data indicates that rather large values of the soft breaking
parameter M_{1/2} in the region greater than 500 GeV are preferred.


title:
Simulation of nuclear effects in quasi elastic and resonant neutrino
  interactions

abstract:
  The effects of nuclear re-interactions in quasi elastic and resonant neutrino
interactions have been considered in the framework of the nuclear models of the
DPMJET code. A preliminary investigation on the modifications induced on the
final state has been performed. Some consequences affecting the experimental
identification are discussed.


title:
Equilibration and Particle Production in an Increasingly Strongly
  Interacting Parton Plasma

abstract:
  We report on a new equilibration scenario in relativistic heavy ion
collisions, the scenario of the Increasingly Strongly Interacting Parton
Plasma, and the effects of this scenario on equilibration and open charm,
photon and dilepton production. The parton plasma is shown to be a very special
kind of many-body system, which contains new physics concerning the approach
towards equilibrium. This is likely to be unique to the parton plasma.


title: Implications of Planck and MAP Measurements On Sparticle Spectra

abstract:
  Future sattelite (MAP and Planck) balloon and ground based experiments will
the determine the basic cosmological parameters within a few percent. We
examine here the effect of this on constraining the SUSY parameter space for
supergravity R-parity conserving models (with tanbeta < 25) for the cases of
nuCDM and LambdaCDM cosmological models. For the nuCDM (LambdaCDM) models, the
gluino mass is restricted by m_g~ < 720(540)GeV. In both cases, the
cosmological constraints are sensitive to non-universal SUSY soft breaking
producing a lower bound m_g~ > 400GeV in some regions and for the nuCDM model,
gaps in the allowed m_g~ range for other regions. For gluino (neutralino)
masses greater than 450(65)GeV, m_0 is constrained to be small making the quark
and slepton mass light generally light and detrmined mostly by m_g~.


title:
Pattern of Texture Zeroes in Quark Mass Matrices With a Divergent
  Top-Yukawa Coupling at the GUT Scale

abstract:
  In a SUSY GUT model responsible for generating symmetric quark mass matrices
at the GUT scale (mu = Lamda) we assume that the top-Yukawa coupling, lamda_t,
becomes infinite at that scale. As a consequence, the MSSM renormalization
group equations for quark Yukawa couplings exhibit hierarchical solutions which
lead to a pattern of texture zeroes in quark mass matrices at mu = Lamda
similar to one of the solutions of Ramond, Roberts, and Ross. The evolution in
energy scale to low energies shows excellent agreement between the measured
quantities involving the scale-independent ratios of CKM matrix elements and
their predicted values in terms of quark mass ratios. It is noted that the
tt-bar condensate model of Bardeen, et al. predicts an infinite lamda_t at mu =
Lamda implying, for our model, that at mu = Lamda, both the symmetry of Yukawa
matrices and condensate dynamics may have a common origin.


title:
Effective dynamics of soft non-abelian gauge fields at finite
  temperature

abstract:
  We consider time dependent correlation functions of non-abelian gauge fields
at finite temperature. An effective theory for the soft ($p\sim g^2 T$) field
modes is derived by integrating out the field modes with momenta of order $T$
and of order $g T$ in a leading logarithmic approximation. In this effective
theory the time evolution of the soft fields is determined by a local
Langevin-type equation. As an application, the rate for hot electroweak baryon
number violation is estimated as $\Gamma \sim g^2 \log(1/g) (g^2 T)^4$.
Furthermore, possible consequences for non-perturbative lattice computations of
unequal time correlation functions are discussed.


title:
Comparing and contrasting the $\nu_{\mu} \to \nu_{\tau}$ and $\nu_{\mu}
  \to \nu_s$ solutions to the atmospheric neutrino problem with SuperKamiokande
  data

abstract:
  The $\nu_{\mu} \to \nu_{\tau}$ and $\nu_{\mu} \to \nu_s$ solutions to the
atmospheric neutrino problem are compared with SuperKamiokande data. The
differences between these solutions due to matter effects in the Earth are
calculated for the ratio of $\mu$-like to $e$-like events and for up-down flux
asymmetries. These quantities are chosen because they are relatively
insensitive to theoretical uncertainties in the overall neutrino flux
normalisation and detection cross-sections and efficiencies. A $\chi^2$
analysis using these quantities is performed yielding $3\sigma$ ranges which
are approximately given by $(0.725 - 1.0, 4 \times 10^{-4} - 2 \times 10^{-2}
eV^2)$ and $(0.74 - 1.0, 1 \times 10^{-3} - 2 \times 10^{-2} eV^2)$ for
$(\sin^2 2\theta,\Delta m^2)$ for the $\nu_{\mu} \to \nu_{\tau}$ and $\nu_{\mu}
\to \nu_s$ solutions, respectively. Values of $\Delta m^2$ smaller than about
$2 \times 10^{-3}$ eV$^2$ are disfavoured for the $\nu_{\mu} \to \nu_s$
solution, suggesting that future long baseline experiments should see a
positive signal if this scenario is the correct one.


title: Singlet Polarization Functions at O(\alpha_s^2)

abstract:
  We consider the three-loop singlet diagrams induced by axial-vector, scalar
and pseudo-scalar currents. Expansions for small and large external momentum
$q$ are presented. They are used in combination with conformal mapping and
Pad\'e approximations in order to arrive at results for the polarization
functions valid for all $q^2$. Results are presented for the imaginary parts
which are directly related to physical quantities like the production of top
quarks or the decay of scalar or pseudo-scalar Higgs bosons.


title:
Equivalence of renormalized covariant and light-front perturbation
  theory: II. Transverse divergences in the Yukawa model

abstract:
  Light-front dynamics can only become a viable alternative to the covariant
approach if doubts about its covariance can be taken away. As a minimal
requirement we take that the physical quantities calculated with light-front
perturbation theory are the same as those obtained using covariant perturbation
theory. If this situation occurs, we use the word equivalent to characterize
it. For quantities that involve the calculation of superficially convergent
diagrams, proofs of equivalence exist. For some types of divergent diagrams the
proof of equivalence is complicated. Longitudinal divergences were dealt with
in Part I. (hep-ph/9702311). In Part II we deal with diagrams with transverse
divergences. Our method is based on minus regularization, which is inspired on
BPHZ regularization. In a calculation using numerical methods we show how to
obtain a rotationally invariant amplitude for two triangle diagrams
contributing to the decay of a scalar boson in the Yukawa model. It concludes
our proof of equivalence of covariant and light-front perturbation theory.


title: Transport coefficients in the early universe

abstract:
  We calculate numerically the electrical conductivity $\sigma$, heat
conductivity $\kappa$ and shear viscosity $\eta$ of the hot plasma present in
the early universe for the temperature interval $1\MeV\lsim T\lsim 10\GeV$. We
use the Boltzmann collision equation to compute all the scattering matrix
elements and regulate them by the thermal masses of the $t$- and $u$-channel
particles. No leading order approximation is needed because of the numerical
integration routines used.


title:
Thermal dilepton signal versus dileptons from open charm and bottom
  decays in heavy-ion collisions

abstract:
  We analyze the opportunity to observe thermal dileptons emitted off
deconfined matter resulting in heavy-ion collisions at RHIC and LHC energies.
Special kinematical conditions provided by the detector systems PHENIX and
ALICE, and the so-called $M_\perp$ scaling behavior of thermal dilepton spectra
are taken into account. Our considerations include energy loss effects of the
fast heavy quarks in deconfined matter, which for themselves can help to
identify the creation of a hot and dense parton medium. Due to a threshold like
effect for decay leptons we find a window at large transverse pair momentum and
fixed transverse mass where the thermal signal can exceed the background of
dileptons from correlated semileptonic decays of charm and bottom mesons.


title: Renormalizing Heavy Quark Effective Theory at O(1/m_Q^3)

abstract:
  We present a calculation of the renormalized HQET Lagrangian at order
O(1/m_Q^3) in the one particle sector. The anomalous dimensions of local
operators and time ordered products of dimension 7 contributing at this order
are calculated in the one loop approximation. We show that a careful treatment
of the time ordered products is necessary to arrive at a gauge independent
renormalized lagrangian. Our result sets the stage for an investigation of
reparametrization invariance at O(1/m_Q^3).


title: Limits on the mass of the lightest Higgs in supersymmetric models

abstract:
  In supersymmetric models extended with a gauge singlet the mass of the
lightest Higgs boson has contributions proportional to the adimensional
coupling $\lambda$. In minimal scenarios, the requirement that this coupling
remains perturbative up to the unification scale constrains $\lambda$ to be
smaller than $\approx 0.7$. We study the maximum value of $\lambda$ consistent
with a perturbative unification of the gauge couplings in models containing
nonstandard fields at intermediate scales. These fields appear in scenarios
with gauge mediation of supersymmetry breaking. We find that the presence of
extra fields can raise the maximum value of $\lambda$ up to a 19%, increasing
the limits on the mass of the lightest Higgs from 135 GeV to 155 GeV.


title: Energy of electroweak sphalerons in 1-loop selfconsistent calculations

abstract:
  We calculate the energy of electroweak sphalerons including one-loop
fermionic corrections. This calculation has previously been done by adding the
correction to the tree-level sphaleron and interpreting the resulting energy as
the 1-loop energy. However, in this paper we calculate the energy by doing a
full renormalisation of the parameters on 1-loop-level and redetermining the
sphaleron configuration using the full energy functional. When comparing the
final result with the tree-level solution we find that the 1-loop calculation
will only cause small deviations of the sphaleron energy.


title:
Critical Exponents and Critical Amplitude Ratio of The Scalar Model from
  Finite-temperature Field Theory

abstract:
  The critical exponents and the critical amplitude ratio of the scalar model
are determined using finite-temperature field theory with auxiliary mass. A new
numerical method is developed to solve an evolution equation. The results are
discussed in comparison with values obtained from the other methods.


title: Supersymmetry Phenomenology

abstract:
  The phenomenological implications of a low-energy supersymmetry are surveyed,
with particular attention given to unification constraints and the role of a
large top quark Yukawa couplings. Generic expectations for sparticle mass
spectra are presented along with prospects for their discovery and study at
present and future colliders.


title: Physics at Muon Colliders

abstract:
  The potential of muon colliders to address fundamental physics issues is
explored, with emphasis on understanding the nature of electroweak symmetry
breaking. The $s$-channel production of Higgs bosons, unique to a muon
collider, along with precision measurements of W^+W^-, t\bar t, and Zh
thresholds would determine the properties of Higgs bosons and test electroweak
radiative corrections. At the high energy frontier, a 4 TeV muon collider is
ideally suited to study either the production of supersymmetric scalar
particles or a strongly interacting WW sector.


title: Isolated photons in perturbative QCD

abstract:
  I present a definition of the cross section for the production of an isolated
photon plus $n$ jets which only depends upon direct photon production, and it
is independent of the parton-to-photon fragmentation contribution. This
prescription, based on a modified cone approach which implements the isolation
condition in a smooth way, treats in the same way quarks and gluons and can be
directly applied to experimental data in hadron-hadron, photon-hadron and
$\epem$ collisions. The case of several, isolated photons in the final state
can also be dealt with in the very same way.


title: QCD Sum Rules for Exclusive Decays of Heavy Mesons

abstract:
  Applications of QCD sum rules to exclusive decays of heavy mesons are
reviewed. In detail, we discuss the calculations of the B and $D$ decay
constants, the heavy-to-light form factors $f^+(p^2)$ and $f^0(p^2)$, and the
strong couplings $g_{B^*B\pi}$ and $g_{D^*D\pi}$. Predictions are presented for
the semileptonic weak decays $B \to \pi \bar{l} \nu_l$ and $B \to \rho \bar{l}
\nu_l$, and used to extract $V_{ub}$ from the measured decay widths. Results
are also shown on $D \to \pi \bar{l} \nu_l$ and $D^* \to D \pi$. Furthermore,
we reconsider the factorization hypothesis in nonleptonic two-body decays, and
describe a sum rule estimate of the nonfactorizable contribution to the
amplitude of $B \to J/\psi K$.


title: Study of the Uncertainty of the Gluon Distribution

abstract:
  The uncertainty in the calculation of many important new processes at the
Tevatron and LHC is dominated by that concerning the gluon distribution
function. We investigate the uncertainty in the gluon distribution of the
proton by systematically varying the gluon parameters in the global QCD
analysis of parton distributions. The results depend critically on the parton
momentum fraction x and the QCD scale Q^2. The uncertainties are presented for
integrated gluon-gluon and gluon-quark luminosities for both the Tevatron and
LHC as a function of sqrt(tau)=sqrt(x1x2)=sqrt(shat/s), the most relevant
quantity for new particle production. The uncertainties are reasonably small,
except for large x.


title:
Charginos and Neutralinos in the Light of Radiative Corrections: Sealing
  the Fate of Higgsino Dark Matter

abstract:
  We analyze the LEP constraints from searches for charginos $\chi^{\pm}$ and
neutralinos $\chi_i$, taking into account radiative corrections to the
relations between their masses and the underlying Higgs-mixing and gaugino-mass
parameters $\mu, m_{1/2}$ and the trilinear mass parameter $A_t$. Whilst
radiative corrections do not alter the excluded domain in $m_{\chi^{\pm}}$ as a
function of $m_{\chi^{\pm}} - m_{\chi}$, its mapping into the $\mu, m_{1/2}$
plane is altered. We update our previous lower limits on the mass of gaugino
dark matter and on tan$\beta$, the ratio of Higgs vacuum expectation values, in
the light of the latest LEP data and these radiative corrections. We also
discuss the viability of Higgsino dark matter, incorporating co-annihilation
effects into the calculation of the Higgsino relic abundance. We find that
Higgsino dark matter is viable for only a very limited range of $\mu$ and
$m_{1/2}$, which will be explored completely by upcoming LEP runs.


title:
Supersymmetry Breaking and the Supersymmetric Flavour Problem: An
  Analysis of Decoupling the First Two Generation Scalars

abstract:
  The supersymmetric contributions to the Flavor Changing Neutral Current
processes may be suppressed by decoupling the scalars of the first and second
generations. It is known, however, that the heavy scalars drive the stop mass
squareds negative through the two-loop Renormalization Group evolution. This
tension is studied in detail. Two new items are included in this analysis: the
effect of the top quark Yukawa coupling and the QCD corrections to the
supersymmetric contributions to $\Delta m_K$. Even with Cabibbo-like degeneracy
between the squarks of the first two generations, these squarks must be heavier
than $\sim 40$ TeV to suppress $\Delta m_K$. This implies, in the case of a
high scale of supersymmetry breaking, that the boundary value of the stop mass
has to be greater than $\sim 7$ TeV to keep the stop mass squared positive at
the weak scale. Low-energy supersymmetry breaking at a scale that is of the
same order as the mass of the heavy scalars is also considered. In this case
the finite parts of the two-loop diagrams are computed to estimate the
contribution of the heavy scalar masses to the stop mass squared. It is found
that for Cabibbo-like mixing between the squarks, the stop mass at the boundary
needs to be larger than $\sim 2$ TeV. Thus, for both cases, the large boundary
value of the stop masses leads to an unnatural amount of fine tuning to obtain
the correct $Z$ mass.


title: Nonperturbative QCD contribution to gluon-gluon-eta' vertex

abstract:
  We investigate the momentum dependence of the g*-g-eta' vertex form factor in
the presence of the nonperturbative QCD vacuum condensate. The behaviour of
this form factor is crucial for, among other things, some proposed mechanisms
devised to explain the large branching ratio for fast eta' production in
charmless B decays observed by CLEO. We show that the leading momentum
dependence of this vertex form factor is not altered when the contribution of
nonperturbative quark condensate is considered.


title: A Mechanism for Baryogenesis in Low Energy Supersymmetry Breaking Models

abstract:
  A generic prediction of models where supersymmetry is broken at scales within
a few orders of magnitude of the weak scale and is fed down to the observable
sector by gauge interactions is the existence of superconducting cosmic strings
which carry baryon number. In this paper we propose a novel mechanism for the
generation of the baryon asymmetry which takes place at temperatures much lower
than the weak scale. Superconducting strings act like ``bags'' containing the
baryon charge and protect it from sphaleron wash-out throughout the evolution
of the Universe, until baryon number violating processes become harmless. This
mechanism is efficient even if the electroweak phase transition in the MSSM is
of the second order and therefore does not impose any upper bound on the mass
of the Higgs boson. (13kb)


title: Naturally Nonminimal Supersymmetry

abstract:
  We consider the bounds imposed by naturalness on the masses of superpartners
for arbitrary points in nonminimal supersymmetric extensions of the standard
model and for arbitrary messenger scales. This constitutes a significant
generalization of previous work along these lines. We discuss appropriate
measures of naturalness and the status of nonminimal supersymmetry in the light
of recent experimental results.


title:
Nuclear Dependence in Transverse Momentum Distribution for Drell-Yan
  Pair

abstract:
  In terms of multiple scattering picture, I compute the nuclear dependence in
Drell-Yan transverse momentum distribution, $d\sigma / dQ^2 dq_T^2$, in
hadron-nucleus collisions. I present the results for large $q_T$ region and
discuss the possible suppression in small $q_T$ region.


title: A Next-to-Minimal Supersymmetric Model of Hybrid Inflation

abstract:
  In this talk we discuss a model of inflation based on a simple variant of the
NMSSM, called $\phi$NMSSM \cite{phiNMSSM}, where the additional singlet $\phi$
plays the role of the inflaton in hybrid (or inverted hybrid) type models. As
in the original NMSSM, the $\phi$NMSSM solves the $\mu$ problem of the MSSM via
the VEV of a gauge singlet $N$, but unlike the NMSSM does not suffer from
domain wall problems since the offending $Z_3$ symmetry is replaced by an
approximate Peccei-Quinn symmetry which also solves the strong CP problem, and
leads to an invisible axion with interesting cosmological consequences. The
model predicts a spectral index $n=1$ to one part in $10^{12}$.


title: Supersymmetry Phenomenology at Hadron Colliders

abstract:
  The phenomenology of a low-energy supersymmetry at hadron colliders is
discussed with consideration of the minimal supergravity model, with a large
top quark Yukawa coupling at the grand unification mass scale, and gauge
mediated symmetry breaking models. Possible supersymmetry interpretations of
some unexplained events are mentioned.


title: Out of Equilibrium Fields in Inflationary Dynamics. Density Fluctuations

abstract:
  The energy and time scales during the inflationary stage of the universe
calls for an out of equilibrium quantum field treatment. Moreover, the high
energy densities involved make necessary the use of non-perturbative approaches
as large N and Hartree methods. We start these lectures by introducing such
non-perturbative out of equilibrium methods in cosmological universes. We
discuss the renormalization procedure and the choice of initial conditions. We
then study the nonlinear dynamics of quantum fields in matter and radiation
dominated FRW and de Sitter universes. For a variety of initial conditions, we
compute the evolution of the inflaton,its quantum fluctuations and the equation
of state. We investigate the explosive particle production due to spinodal
unstabilities and parametric amplification in FRW and de Sitter universes with
and without symmetry breaking.We find that the particle production is sensitive
to the expansion of the universe.For symmetry breaking scenarios, we determine
generic late time fields behavior for FRW and deSitter cosmologies.We find that
quantum fluctuations damp in FRW as the square of the scale factor while the
order parameter approaches a minimum of the potential at the same rate.We con-
sider an O(N) inflaton model coupled self-consistently to gravity in the semi-
classical approximation for a `new inflation' scenario. We find that spinodal
instabilities drive the growth of non-perturbatively large quantum fluctuations
which shut off inflation. These fluctuations assemble with the inflaton zero
mode yielding a new effective field that actually rolls down behaving classi-
cally. We compute the amplitude and index for scalar density and tensor
perturbations. In all models of this type the spinodal instabilities produce a
`red' spectrum of primordial scalar density perturbations.


title: Accurate Cosmological Parmeters and Supersymmetric Particle Properties

abstract:
  Future sattelite, balloon and ground based experiments will give precision
determinations of the basic cosmological parameters and hence determine the
amount of cold dark matter accurately. We consider here two cosmological
models, the nuCDM model and the LambdaCDM model, and examine within the
framework of supergravity grand unification the effect this will have for these
models on supersymmetry searches at accelerators. In the former example the
gluino (neutralino) mass has an upper bound of about 720(100) GeV and gaps
(forbidden regions) may deveop at lower energies. In the latter case the upper
bound occurs at gluino (neutralino) mass of about 520(70) GeV with squarks and
selectron becoming light when gluino (neutralino) masses are greater than
420(55) GeV. Both models are sensitive to non-universal soft breaking masses,
and show a correlation between large (small) dark matter detector rates and low
(high) b -> s+ gamma branching ratio.


title: Z_3 Strings and their Interactions

abstract:
  We construct Z_3 vortex solutions in a model in which SU(3) is spontaneously
broken to Z_3. The model is truncated to one in which there are only two
dimensionless free parameters and the interaction of vortices within this
restricted set of models is studied numerically. We find that there is a curve
in the two dimensional space of parameters for which the energy of two
asymptotically separated vortices equals the energy of the vortices at
vanishing separation. This suggests that the inter-vortex potential for Z_3
strings might be flat for these couplings, much like the case of U(1) strings
in the Bogomolnyi limit. However, we argue that the intervortex potential is
attractive at short distances and repulsive at large separations leading to the
possibility of unstable bound states of Z_3 vortices.


title:
Nonperturbative Effects in $\bar B\to X_s l^+l^-$ for Large Dilepton
  Invariant Mass

abstract:
  We reconsider the calculation of ${\cal O}(\Lambda^2_{QCD}/m^2_b)$
nonperturbative corrections to $\bar B\to X_sl^+l^-$ decay. Our analysis
confirms the results of Ali et al. for the dilepton invariant mass spectrum,
which were in disagreement with an earlier publication, and for the lepton
forward-backward asymmetry. We also give expressions for the ${\cal
O}(\Lambda^2_{QCD}/m^2_b)$ corrections to the left-right asymmetry. In addition
we discuss the breakdown of the heavy quark expansion near the point of maximal
dilepton invariant mass $q^2$ and consider a model independent approach to this
region using heavy hadron chiral perturbation theory. The modes $\bar B\to\bar
Kl^+l^-$ and $\bar B\to\bar K\pi l^+l^-$, which determine the endpoint region
of the inclusive decay, are analyzed within this framework. An interpolation is
suggested between the region of moderately high $q^2$, where the heavy quark
expansion is still valid, and the vicinity of the endpoint described by chiral
perturbation theory. We also comment on further nonperturbative effects in
$\bar B\to X_sl^+l^-$.


title:
Implications of CHOOZ results for the decoupling of solar and
  atmospheric neutrino oscillations

abstract:
  We have considered the results of solar and atmospheric neutrino oscillation
experiments in the scheme of mixing of three neutrinos with a mass hierarchy.
It is shown that the recent results of the CHOOZ experiment imply that
|U_{e3}|^2<<1 (U is the neutrino mixing matrix), that the oscillations of solar
neutrinos are described by the two-generation formalism and that the
oscillations of solar and atmospheric neutrinos decouple. It is also shown that
if not only |U_{e3}|^2<<1 but also |U_{e3}|<<1, then the oscillations of
atmospheric neutrinos do not depend on matter effects and are described by the
two-generation formalism. In this case, with an appropriate identification of
the mixing parameters, the two-generation analyses of solar and atmospheric
neutrino data provide direct information on the mixing parameters of three
neutrinos. We discuss the possibility to get information on |U_{e3}|^2 in
long-baseline neutrino oscillation experiments.


title:
Determination of the CKM angle gamma and |V_{ub}/V_{cb}| from inclusive
  direct CP asymmetries and branching ratios in charmless B decays

abstract:
  We have calculated inclusive direct CP-asymmetries for charmless B^{+/-}
-decays. After summing large logarithms to all orders the CP-asymmetries in
Delta S=0 and Delta S=1 decays are found as
  a_{CP} (Delta S=0) = (2.0 +1.2/-1.0)%
  and
  a_{CP} (Delta S=1) = ( -1.0 +/- 0.5)%.
  These results are much larger than previous estimates based on a work without
summation of large logarithms. We further show that the dominant contribution
to a_{CP} (\Delta S=0 ) is proportional to (sin gamma) times |V_{cb}/V_{ub}|.
The constraints on the apex (rho-bar,eta-bar) of the unitarity triangle
obtained from these two CP-asymmetries define circles in the
(rho-bar,eta-bar)-plane. We have likewise analyzed the information on the
unitarity triangle obtainable from a measurement of the average non-leptonic
branching ratios Br(Delta S=0), Br(Delta S=1) and their sum Br_{NL} (B --> no
charm). These CP-conserving quantities define circles centered on the
rho-bar--axis of the (rho-bar,eta-bar)-plane. We expect a determination of
|V_{ub}/V_{cb}| from Br_{NL} (B --> no charm) to be promising. Our results
contain some new QCD corrections enhancing Br(Delta S=1), which now exceeds
Br(Delta S=0) by roughly a factor of two.


title:
Determination of parameters of Higgs sector in the minimal
  supersymmetric Standard Model

abstract:
  We examine whether parameters related to Higgs sector of the minimal
supersymmetric standard model can be determined by detailed study of production
cross section and decay branching ratios of the Higgs boson.
  Assuming that only the light Higgs boson is observed at a future $e^+e^-$
linear collider with $\sqrt{s}=300\sim500$GeV, we show that values of
$m_{susy}$ and $\tan\beta$ are restricted within a narrow limits in the
$m_{susy}$ versus $\tan\beta$ plane by the combined analysis of the light Higgs
properties.
  It is also pointed out that, in some case, the value of $\tb$ may be
restricted within a relatively low value, $\tb=1\sim5$.


title:
Complete next-to-leading order perturbative QCD prediction for the pion
  electromagnetic form factor

abstract:
  We present the results of a complete leading-twist next-to-leading order
(NLO) QCD analysis of the spacelike pion electromagnetic form factor at large
momentum transfer Q. We have studied their dependence on the form of the pion
distribution amplitude. For a given distribution amplitude, we have examined
the sensitivity of the predictions to the choice of the renormalization and
factorization scales. Theoretical uncertainty of the LO results related to the
renormalization scale ambiguity has been significantly reduced by including the
NLO corrections. Adopting the criteria according to which a NLO prediction is
considered reliable if, both, the ratio of the NLO to LO contributions and the
strong coupling constant are reasonably small, we find that reliable
perturbative predictions for the pion electromagnetic form factor with all
distribution amplitudes considered can already be made at a momentum transfer
Q<10 GeV, with corrections to the LO results being typically of the order of ~
20%. To check our predictions and to discriminate between the distribution
amplitudes, it is necessary to obtain experimental data extending to higher
values of Q.


title: Soft FSI Systematics for charmless strange $B^\pm$ Decays

abstract:
  New results going beyond those obtained from isospin and flavor symmetry and
subject to clear experimental tests are obtained for effects of FSI in $B^\pm$
decays to final states containing neutral flavor-mixed mesons like $\omega$,
$\phi$, $\eta$ and $\eta'$. The most general strong-interaction diagrams
containing arbitrary numbers of quarks and gluons are included with the
assumptions that any $q \bar q$ pair created by gluons must be a flavor
singlet, and that there are no hairpin diagrams in which a final meson contains
a $q \bar q$ pair from the same gluon vertex. The smallness of $K^- \eta$
suggests that it might have a large CP violation. A sum rule is derived to test
whether the large $K^- \eta'$ requires the addition of an additional glueball
or charm admixture. Further analysis from $D_s$ decay systematics supports this
picture of FSI and raises questions about charm admixture in the $\eta'$.


title: Orbital Angular Momentum in the Chiral Quark Model

abstract:
  We developed a new and unified scheme for describing both quark spin and
orbital angular momenta in symmetry-breaking chiral quark model. The loss of
quark spin in the chiral splitting processes is compensated by the gain of the
orbital angular momentum carried by quarks and antiquarks. The sum of both spin
and orbital angular momenta carried by quarks and antiquarks is 1/2. The
analytic and numerical results for the spin and orbital angular momenta carried
by quarks and antiquarks in the nucleon are given. Extension to other octet and
decuplet baryons is also presented. Possible modification and application are
discussed.


title: Jupiter Effect (Asymmetrical Production of Dilepton Pairs)

abstract:
  Specific results of the computer simulation of dilepton production from
expanding pion gas created in Pb+Pb 160 GeV/n collisions are presented.
Azimuthal asymmetry of dilepton pairs in non-central collisions and interesting
shape of the rapidity distribution of dilepton pairs are predicted. These
results are understood on theoretical level as a consequence of momentum and
space asymmetries in the initial state of pion gas without any assumption of
thermalization. Implication on the production of dileptons in pre-hadronic
phase of HIC is drawn.


title: Neutrino properties from reactor and accelerator experiments

abstract:
  In this talk, I discuss the general theory of neutrino oscillation
experiments, putting special emphasis on the momentum distribution of the
incoming neutrino beam. Then I discuss recent neutrino oscillation experiments,
viz., LSND, KARMEN and CHOOZ. Experiments foreseeable in the near future have
also been discussed at the end.


title: Three Neutrino $\Delta m^2$ scales and Singular Seesaw Mechanism

abstract:
  It is shown that the singular seesaw mechanism can simultaneously explain all
the existing data supporting nonzero neutrino masses and mixing. The three
mass-squared differences that are needed to accommodate the atmospheric
neutrino data (through $\nu_\mu - \nu_s$ oscillation), the solar neutrino data
via MSW mechanism (through $\nu_e - \nu_\tau$ oscillation), and the positive
result of $\nu_\mu - \nu_e$ oscillation from LSND can be generated by this
mechanism, whereas the vacuum oscillation solution to the solar neutrino
problem is disfavored. We find that the electron and tau neutrino masses are of
order $10^{-3}$ eV, and the muon neutrino and a sterile neutrino are almost
maximally mixed to give a mass of order 1 eV. Two heavy sterile neutrinos have
a mass of order 1 keV which can be obtained by the double seesaw mechanism with
an intermediate mass scale $\sim 10^5$ GeV. A possible origin of such a scale
is discussed.


title: Baryogenesis, Inflation and Superstrings

abstract:
  We study the conditions for successful Affleck-Dine baryogenesis in generic
inflation and supergravity scenarios, finding powerful restrictions on them.
String-based SUGRA models are especially interesting since they are
surprisingly suitable for the implementation not only of AD baryogenesis but
also inflation itself, presenting a nice solution to the $\eta$--problem.


title: Vector mesons in medium

abstract:
  Based on an effective Lagrangian which combines chiral SU(3) dynamics with
vector meson dominance, we have developed a model for the forward vector
meson-nucleon scattering amplitudes. We use this as an input to calculate the
low energy part of the current-current correlation function in nuclear matter.
For the isovector channel we find a significant enhancement of the in-medium
spectral density below the $\rho$ resonance while the $\rho$ meson mass itself
changes only slightly. The situation is different in the isoscalar channel,
where the mass and peak position of the $\omega$ meson move downward while its
width increases moderately. For the $\phi$ meson we find almost no mass shift,
but the width of the peak increases significantly. We use these spectra as
``left hand side'' of in medium QCD sum rules and observe a remarkable degree
of consistency with the operator product expansion ``right hand''side in all
three channels. We point out, however, that these results cannot simply be
interpreted, as commonly done, in terms of a universal rescaling of vector
meson masses in matter. We also compare the resulting thermal dilepton rates of
our model with CERES data. We find satisfactory agreement but we point out that
the dilepton rates from completely uncorrelated quark-antiquark pairs also fit
the data quite well. Considering the strongly attractive potential for the
$\omega$ together with its comparably small width, we discuss the possible
formation of bound $\omega$ states in nuclei. Using a Green's function approach
we investigate the possibility of detecting these bound states in the $A(d,
^3He) $ pick-up reaction.


title: New Particles and Interactions at High Energy Muon Colliders

abstract:
  I give an overview of the ability of a high energy $\mu^+\mu^-$ collider to
discover new particles and interactions. I start with heavy fermions which will
be the most straightforward to produce and observe. I then discuss single
leptoquark production which is produced via the quark content of the photon and
the discovery potential for extra gauge bosons which will manifest themselves
via deviations of observables from their standard model values. Finally,
contact interactions are studied as the generalization of looking for new
interactions via deviations from the standard model.


title: Threshold cross section measurements

abstract:
  Accurate measurements of particles masses, couplings and widths are possible
by measuring production cross sections near threshold. We discuss the prospects
for performing such measurements at a high luminosity muon collider.


title:
Snapshots of Hadrons, or the Story of How the Vacuum Medium Determines
  the Properties of the Classical Mesons Which Are Produced, Live and Die in
  the QCD Vacuum

abstract:
  1. QCD Sum Rules: 20 Years After;
  2. QCD Vacuum and Basics of the SVZ Method:
  2.1 General ideas; 2.2. Getting started/Playing with toy models;
  3. Vacuum Condensates;
  4. Rho Meson in QCD;
  5. Basic Theoretical Instrument -- Wilson's OPE;
  6. Practical Version of OPE;
  7. Low Energy Theorems;
  8. Are All Hadrons Alike?
  9. Ecological Niche;
  10. New Developments:
  10.1 Light-cone sum rules; 10.2 Heavy flavor sum rules;
  11. Sum Rules and Lattices;
  12. Vacuum Fluctuations are Subtle Creatures;
  13. Instead of Conclusions.


title: Gluon Radiation in Top Production and Decay at Lepton Colliders

abstract:
  In this talk we discuss gluon radiation in top production and decay. After
reviewing results for hadron colliders we consider soft gluon radiation at
lepton colliders and present gluon distributions that are potentially sensitive
to production-decay interference effects.


title:
Topcolor and the First Muon Collider (Talk presented at the Workshop on
  Physics at the First Muon Collider and at the Front End of the Muon Collider,
  Nov. 1997)

abstract:
  We describe a class of models of electroweak symmetry breaking that involves
strong dynamics and top quark condensation. A new scheme based upon a seesaw
mechanism appears particularly promising. Various implications for the
first-stage muon collider are discussed.


title: Hadronic B Decays

abstract:
  We review recent experimental results from CLEO and LEP experiments on
hadronic decays of hadrons containing $b$ quarks. We discuss charm counting and
the semileptonic branching fraction in $B$ decays and the color suppressed
amplitude in $B$ decay. (to appear in the Proceedings of 1997 Heavy Flavors
Conference in Santa Barbara)


title: Relations between Observables and the Infrared Fixed-Point in QCD

abstract:
  We investigate the possibility that alpha_s freezes as function of N_f within
perturbation theory. We use two approaches -- direct search for a zero in the
effective-charge (ECH) beta function, and the Banks-Zaks (BZ) expansion. We
emphasize the fundamental difference between quantities with space-like vs.
those with time-like momentum. We show that within the ECH approach several
space-like quantities exhibit similar behavior. In general the 3-loop ECH beta
functions can lead to freezing for N_f\gsim 5, but higher-order calculations
are essential for a conclusive answer. The BZ expansion behaves differently for
different observables. Assuming that the existence of a fixed point requires
convergence of the BZ expansion for any observable, we can be pretty sure that
there is no fixed point for N_f\lsim 12. The consequences of the Crewther
relation concerning perturbative freezing are analyzed. We also emphasize that
time-like quantities have a consistent infrared limit only when the
corresponding space-like effective charge has one. We show that perturbative
freezing can lead to an analyticity structure in the complex momentum-squared
plane that is consistent with causality.


title: Muon-proton Colliders: Leptoquarks and Contact Interactions

abstract:
  The muon-proton ($\mu p$) collider is an interesting option of the muon
collider. Here we discuss the physics potential of the $\mu p$ collider;
especially, leptoquarks and contact interactions. We calculate the sensitivity
reach for the second generation leptoquarks and leptogluons, $R$-parity
violating squarks, and $\mu q$ contact interactions for the $\mu p$ colliders
of various energies and luminosities.


title: Constraints on Very Light Axions from Cavity Experiments

abstract:
  In view of the ongoing galactic (or cosmic) axion detection experiments, we
compare the axion-photon-photon coupling $c_{a\gamma\gamma}$'s for various
invisible (or very light) axion models.


title:
A Solution to the Strong CP Problem with Gauge-Mediated Supersymmetry
  Breaking

abstract:
  We demonstrate that a certain class of low scale supersymmetric
``Nelson-Barr'' type models can solve the strong and supersymmetric CP problems
while at the same time generating sufficient weak CP violation in the
$K^{0}-\bar{K}^{0}$ system. In order to prevent one-loop corrections to
$\bar{\theta}$ which violate bounds coming from the neutron electric dipole
moment (EDM), one needs a scheme for the soft supersymmetry breaking parameters
which can naturally give sufficient squark degeneracies and proportionality of
trilinear soft supersymmetry-breaking parameters to Yukawa couplings. We show
that a gauge-mediated supersymmetry breaking sector can provide the needed
degeneracy and proportionality, though that proves to be a problem for generic
Nelson-Barr models. The workable model we consider here has the Nelson-Barr
mass texture enforced by a gauge symmetry; one also expects a new U(1) gauge
superfield with mass in the TeV range. The resulting model is predictive. We
predict a measureable neutron EDM and the existence of extra vector-like quark
superfields which can be discovered at the LHC. Because the $3\times 3$
Cabbibo-Kobayashi-Maskawa matrix is approximately real, the model also predicts
a flat unitarity triangle and the absence of substantial CP violation in the
$B$ system at future $B$ factories. We discuss the general issues pertaining to
the construction of such a workable model and how they lead to the successful
strategy. A detailed renormalization group study is then used to establish the
feasibility of the model considered.


title: Excited Heavy Mesons from QCD Sum Rules

abstract:
  Orbitally excited L=1 charm mesons are studied by QCD sum rules in the
framework of heavy quark effective theory. The meson masses and the strong
decay widths are obtained. This talk is based on our works of refs. 1 and 2
collaborated with Y.B. Dai, C.S. Huang, M.Q. Huang and H.Y. Jin.


title:
Dispersive Bounds on The Shape Of Lambda_b to Lambda_c l {\bar \nu_l}
  Formfactors

abstract:
  We derive a theoretically allowed domain for the charge radius $\rho$ and
curvature $c$ of the Isgur-Wise function describing the decay $\Lambda_b \to
\Lambda_c l {\bar \nu_l}$. Our method uses crossing symmetry, dispersion
relations and analyticity in the context of the Heavy Quark Effective Theory
but is independent of the specifics of any given model. The experimentally
determined values of the $\Upsilon$ masses have been used as input information.
The results are of interest for testing different models employed to calculate
the heavy baryon formfactors which are used for the extraction of $| V_{cb} |$
from the experimental data.


title: Decay widths of B_1 and B^*_2 up to the order of O(1/m_Q) in HQET

abstract:
  We first improve the previous results on the masses of the doublets (0^+,1^+)
and (1^+,2^+) with QCD sum rules up to the order of O(1/m_Q) in the framework
of HQET and calculate the O(1/m_Q) correction to the decay constants f_{-,1/2}
and f_{+,3/2}. With the mass matrix of the two 1^+ states, we obtain the mixing
angle for the two states and the interpolating currents, which couple to only
one of the two eigenstates up to the order of O(1/m_Q). Using these results we
derive the light-cone sum rules for the amplitudes of the pionic decay of B_1
and B_2^* up to the order of O(1/m_Q) in HQET. The O(1/m_Q) correction to the
decay amplitude of B_1 and B_2^* are found to be small. When applied to D_1 and
D_2^* the theoretical results are in good agreement with experimental data
though the theoretical uncertainty is sizeable for D system.


title:
Rho decay widths of excited heavy mesons from light-cone QCD sum rules
  in the leading order of HQET

abstract:
  The couplings and decay widths of the proceses (1^+,2^+)->(0^-,1^-)+rho are
studied with ligh-cone QCD sum rules in the leading order of heavy quark
effective theory. These processes are employed to estimate the two pion
transition widths of the (1^+,2^+) doublet through the low mass tail of the rho
resonance. Our calculation shows that the two pion decay widths are much
smaller than the single pion decay widths. However, B_1 and B_2^* mesons should
also have significant two pion decay widths around 1.5 MeV.


title:
Couplings of pions with heavy baryons from light-cone QCD sum rules in
  the leading order of HQET

abstract:
  The couplings of pions with heavy baryons g_2 (\Sigma^*, \Sigma) and
g_3(\Sigma^*, \Lambda) are studied with light-cone QCD sum rules in the leading
order of heavy quark effective theory. Both sum rules are stable. Our results
are g_2=(1.56\pm 0.3), g_3=(0.94\pm 0.06).


title:
Couplings of pions with excited heavy mesons from light cone QCD sum
  rules in the leading order of HQET

abstract:
  The couplings of pions with lowest three doublets (0^-,1^-), (0^+,1^+) and
(1^+,2^+) of heavy mesons are studied with ligh cone QCD sum rules in the
leading order of heavy quark effective theory. The ambiguity due to the
presence of two distinct 1^+ states are solved.


title: Beyond The Standard Model

abstract:
  An overview of unified theory models that extend the standard model is given.
A scenario describing the physics beyond the standard model is developed based
on a finite quantum field theory (FQFT) and the group G=$SO(3,1)\otimes
SU(3)\otimes SU(2)\otimes U(1)$. The field theory is Poincar\'e invariant,
gauge invariant, finite and unitary to all orders of perturbation theory and
has a fundamental scale which is chosen to be $\Lambda_F =1/\sqrt{G_F}\sim 300$
GeV, where $G_F$ is the Fermi coupling constant. The physical Higgs particle is
protected from acquiring a large mass beyond $\sim 1$ TeV, removing the gauge
hierarchy problem associated with the scalar Higgs field. This avoids the need
for a composite Higgs field or supersymmetry. The coupling constants and the
fermion masses can be calculated from a set of low-energy relativistic
eigenvalue equations based on truncated Green's functions and the FQFT,
reducing the number of free parameters in the model without a grand unification
scheme. The proton is predicted to be stable. Quantum gravity is perturbatively
finite and unitary to all orders.


title: Two Lectures On Phase Mixing

abstract:
  The dynamics of phase transitions plays a crucial r\^ole in the so-called
interface between high energy particle physics and cosmology. Many of the
interesting results generated during the last fifteen years or so rely on
simplified assumptions concerning the complex mechanisms typical of
nonequilibrium field theories. After reviewing well-known results concerning
the dynamics of first and second order phase transitions, I argue that much is
yet to be understood, in particular in situations where homogeneous nucleation
theory does not apply. I present a method to deal with departures from
homogeneous nucleation, and compare its efficacy with numerical simulations.
Finally, I discuss the interesting problem of matching numerical simulations of
stochastic field theories with continuum models.


title:
High energy factorization predictions for the charm structure function
  F2^c at HERA

abstract:
  High energy factorization predictions for F2^c are derived using BFKL
descriptions of the proton structure function F2 at HERA. The model parameters
are fixed by a fit of F2 at small x. Two different approaches of the non
perturbative proton input are shown to correspond to the factorization at the
gluon or quark level, respectively. The predictions for F2^c are in agreement
with the data within the present error bars. However, the photon wave-function
formulation (factorization at quark level) predicts significantly higher F2^c
than both gluon factorization and a next-leading order DGLAP model.


title: Inclusive B-Meson Production in e^+ e^- and p p-bar Collisions

abstract:
  We provide nonperturbative fragmentation functions for B mesons, both at
leading and next-to-leading order in the MS-bar factorization scheme with five
massless quark flavors. They are determined by fitting the fractional energy
distribution of B mesons inclusively produced in e^+ e^- annihilation at CERN
LEP1. Theoretical predictions for the inclusive production of B mesons with
high transverse momenta in p p-bar scattering obtained with these fragmentation
functions nicely agree, both in shape and normalization, with data recently
taken at the Fermilab Tevatron.


title: Constraints on Strong Dynamics from Rare B and K Decays

abstract:
  We discuss the constraints from rare B and K decays on the Electroweak
Symmetry Breaking (EWSB) sector, as well as on theories of fermion masses. We
focus on models involving new strong dynamics and show that transitions
involving Flavor Changing Neutral Currents (FCNC) play an important role in
disentangling the physics in these scenarios. In a model-independent approach
to the EWSB sector, the information from rare decays is complementary to
precision electroweak observables in bounding the contributions to the
effective lagrangian. We compare the pattern of deviations from the standard
model that results from these sources, with the deviations associated with the
mechanism for generating fermion masses.


title: Eight-component two-fermion equations

abstract:
  An eight-component formalism is proposed for the relativistic two-fermion
problem. In QED, it extends the applicability of the Dirac equation with
hyperfine interaction to the positronium case. The use of exact relativistic
two-body kinematics entails a CP-invariant spectrum which is symmetric in the
total cms energy. It allows the extension of recent \alpha^6 recoil corrections
to the positronium case, and implies new recoil corrections to the fine and
hyperfine structures and to the Bethe logarithm.


title:
Top quark longitudinal polarization near the threshold in l+ l-
  annihilation

abstract:
  We show that the longitudinal polarization of the top quarks produced in the
annihilation of e+ e- or mu+ mu- into tbar t at energies near the threshold is
not affected by the large Coulomb-type corrections, which greatly modify the
total cross section. Thus the longitudinal polarization, although small, may
provide an independent information on the mass and the width of the top quark,
largely independent of the uncertainty in alpha_s.


title: Linking Geometric Mass Hierarchy with Threefold Family Replication

abstract:
  A link is established between the observed (approximate) geometric mass
hierarchy of quarks and leptons and the triangular structure of their tenable
flavor representations. This singles out SU(3) as the horizontal flavor group,
thereby linking the Fermi mass hierarchy with the threefold family replication.
These linkages are exploited within a flavor-chiral SU(3) model, with fermions
and Higgs bosons in the 3+6* representation. The model is Left-Right symmetric
and utilizes the universal see-saw mechanism with a geometric mass suppression
pattern. Given certain assumptions, the model produces successful mass-ratio
(rather than square-mass-ratio) mixing angle relations and fixes the light
quark mass ratio.


title: Gauge Field Model With Massive Gauge Bosons

abstract:
  A gauge field model, which simultaneously has strict local gauge symmetry and
massive gauge bosons, is discussed in this paper. The model has SU(N) gauge
symmetry. In the limit $\alpha \longrightarrow 0$, the gauge field model
discussed in this paper will return to Yang-Mills gauge field model. The
important meaning of this model is that, without Higgs mechanism, gauge bosons
can also obtain masses. This theory can also explain some other unknown
phenomenum.


title: A New Electroweak Model Without Higgs Boson

abstract:
  In this paper, we try to construct an electroweak model which avoids using
Higgs mechanism. We simultaneously introduce two sets of gauge bosons so as to
keep the masses of gauge bosons $W^{\pm}$ and $Z$ non-zero without using Higgs
mechanism. In order to introduce symmetry breaking, we need a vacuum potential.
In a proper limit, this model will return to the standard model, except that
there exists no Higgs particle and couplings between Higgs particle and
fermions or gauge fields. The fundamental dynamical characteristics of this
model are similar to those of the standard model.


title: Superheavy dark matter

abstract:
  We show that in large-field inflationary scenarios, superheavy (many orders
of magnitude larger than the weak scale) dark matter will be produced in
cosmologically interesting quantities if superheavy stable particles exist in
the mass spectrum. We show that these particles may be produced naturally
during the transition from the inflationary phase to either a matter-dominated
or radiation-dominated phase as a result of the expansion of the background
spacetime acting on vacuum quantum fluctuations of the dark matter field. We
find that as long as there are stable particles whose mass is of the order of
the inflaton mass (presumably around $10^{13}$GeV), they will be produced in
sufficient abundance to give $\Omega_0 =1$ quite independently of any details
of the non-gravitational interactions of the dark-matter field.


title: QCD in the Infrared with Exact Angular Integrations

abstract:
  In a previous paper we have shown that in quantum chromodynamics the gluon
propagator vanishes in the infrared limit, while the ghost propagator is more
singular than a simple pole. These results were obtained after angular
averaging, but in the current paper we go beyond this approximation and perform
an exact calculation of the angular integrals. The powers of the infrared
behaviour of the propagators are changed substantially. We find the very
intriguing result that the gluon propagator vanishes in the infrared exactly
like p^2, whilst the ghost propagator is exactly as singular as 1/p^4. We also
find that the value of the infrared fixed point of the QCD coupling is much
decreased from the y-max estimate: it is now equal to 4\pi/3.


title: Recent Developments in Electroweak baryogenesis

abstract:
  We discuss some recent developments made in the computation of the baryon
asymmetry generated at the electroweak scale. We emphasize that the local
number density asymmetries of the particles involved in supersymmetric
electroweak baryogenesis must be described by a set of Quantum Boltzmann
Equations. These diffusion equations automatically and self-consistently
incorporate the CP-violating sources which fuel baryogenesis and manifest
``memory'' effects which are typical of the quantum transport theory and are
not present in the classical approach.


title: A theory driven analysis of the effective QED coupling at $M_Z$

abstract:
  An evaluation of the effective QED coupling at the scale M_Z is presented. It
employs the predictions of perturbative QCD for the cross section of electron
positron annihilation into hadrons up to order \alpha_s^2, including the full
quark mass dependence, and of order \alpha_s^3 in the high energy region. This
allows to predict the input for the dispersion relations over a large part of
the integration region. The perturbative piece is combined with data for the
lower energies and the heavy quark thresholds. The result for the hadronic
contribution to the running of the coupling \Delta\alpha^{(5)}_{\rm
had}(M_Z^2)= (277.5 \pm 1.7)\times 10^{-4} leads to
(\alpha(M_Z^2))^{-1}=128.927 \pm 0.023. Compared to previous analyses the
uncertainty is thus significantly reduced.


title: Two-Stage Inflation in Supergravity

abstract:
  We investigate the viability of a two-stage inflationary scenario in the
context of supergravity, so as to resolve the problem of initial conditions for
hybrid inflation. We allow for non-renormalizable terms in the superpotential
and consider the most general form of the Kahler potential and the gauge
kinetic function. We construct a model with two stages of inflation, the first
driven by D-term and the second by F-term energy density. The viability of this
scenario depends on the non-minimal terms in the Kahler potential, for which we
derive the necessary constraints.


title: Automation of Feynman Diagram Evaluation

abstract:
  A C-program DIANA (DIagram ANAlyser) for the automation of Feynman diagram
evaluations is presented.


title: Methods to calculate scalar two-loop vertex diagrams

abstract:
  We present a review of the Bielefeld-Dubna activities on multiloop
calculations.


title: Charmonium suppression in heavy-ion collisions

abstract:
  Data and their interpretations are reviewed for $J/\psi$ and $\psi^{\prime}$
production in heavy ion collisions with particular emphasis on the recently
reported discontinuity in $Pb$-$Pb$ reactions. The experimental set-up is
described and the various results for $J/\psi$ and $\psi^{\prime}$ suppressions
including their $p_T$-dependence are presented. The suppressions in $pA$
collisions are discussed in terms of final state absorption of a premeson and
the $p_T$ distributions as parton scattering in the initial state. Both
phenomena scale with the trajectory length $L$. The data for charmonium
suppression and $< p_T^2 >$ in heavy ion collisions are presented as a function
of $L$ and discussed in the light of theories assuming deconfined matter and/or
absorption by comovers.


title: Multiple Scattering Expansion of the Self-Energy at Finite Temperature

abstract:
  An often used rule that the thermal correction to the self-energy is the
thermal phase-space times the forward scattering amplitude from target
particles is shown to be the leading term in an exact multiple scattering
expansion. Starting from imaginary-time finite-temperature field theory, a
rigorous expansion for the retarded self-energy is derived. The relationship to
the thermodynamic potential is briefly discussed.


title: On the Regge Slopes Intramultiplet Relation

abstract:
  We show that only additivity of inverse Regge slopes is consistent with both
the formal chiral limit m(n)\to 0 and the heavy quark limit M(Q)>>M(n), where
n=u,d, and m,M are current and constituent quark masses, respectively.


title:
Towards a physical expansion in perturbative gauge theories by using
  improved Baker-Gammel approximants

abstract:
  Applicability of the previously introduced method of modified diagonal
Baker-Gammel approximants is extended to truncated perturbative series (TPS) of
any order in gauge theories. The approximants reproduce the TPS when expanded
in power series of the gauge coupling parameter to the order of that TPS. The
approximants have the favorable property of being exactly invariant under the
change of the renormalization scale, and that property is arrived at by a
generalization of the method of the diagonal Pad\'e approximants. The
renormalization scheme dependence is subsequently eliminated by a variant of
the method of the principle of minimal sensitivity (PMS). This is done by
choosing the values of the renormalization-scheme-dependent coefficients, which
appear in the beta function of the gauge coupling parameter, in such a way that
the diagonal Baker-Gammel approximants have zero values of partial derivatives
with respect to these coefficients. The resulting approximants are then
independent of the renormalization scale and of the renormalization scheme.


title: Test of Analysis Method for Top-Antitop Production and Decay Events

abstract:
  We have carried out Monte Carlo calculations on two sets of randomly
generated QCD events due to $p\bar{p} \to t \bar{t}$ with top mass $m_t = 170$
GeV, one set leading to $e^+e^-$ or $e^{\pm}\mu^{\mp}$ or $\mu^+\mu^-$ 2jets
(dilepton) and the other leading to $e^{\pm}$ or $\mu^{\pm}$ 4jets (unilepton)
configurations, in order to test the likelihood methods we have proposed for
determining the top mass by analyses of these two sets of configurations. For
the set of unilepton events, our method gives a very efficient and quite sharp
measure of the top mass lying several GeV below the input mass. For the
dilepton set, our method gives a much broader and markedly asymmetric
distribution for the top mass estimates, 75% of them lying below 170 GeV, but
the dilepton data will have much lower background than unilepton data. We then
illustrate these methods by applying them to the data available from CDF in
1995 and discuss the results obtained in relation to the results for the sets
of Monte Carlo events. The dilepton events yield masses spread widely, over 140
to 180 GeV, generally lower than the unilepton events, which cluster around
$175\pm 8$ GeV. In an appendix, we discuss the nature of the additional
``slow'' $\mu^{+}$ observed in one CDF dilepton event, concluding that it is
most probably a ``tertiary lepton'' resulting from the decay sequence $b\to c +
hadrons$, followed by $c\to s \mu^{+} \nu$.


title: Charmonium dissociation in hot and dense matter

abstract:
  We investigate $J/\psi$ suppression in ultrarelativistic heavy ion collisions
within a generalized GLAUBER model and compare results of a hadronic comover
scenario with those of a quark plasma scenario where conditions for MOTT
dissociation of charmonium are fulfilled locally at the short time scales
before hadronization. We study possible consequences for the theoretical
description to be drawn from the observation of ``anomalous'' thresholds in the
$J/\psi$ suppression pattern by the NA50 collaboration.


title:
R-parity violation and CP-violating and CP-conserving spin asymmetries
  in l^+ l^- -> sneutrino -> tau^+ tau^-: probing sneutrino mixing at LEP2, NLC
  and mu^+mu^- colliders

abstract:
  We consider the sneutrino resonance reaction l^+ l^- -> sneutrino -> tau^+
tau^- in the MSSM without R-parity. We introduce new CP-violating and
CP-conserving tau-spin asymmetries which are generated already at the
tree-level if there is sneutrino - sneutrino-bar mixing and that are forbidden
in the SM. It is remarkable that these spin asymmetries can reach ~75% around
resonance for a sneutrino mass splitting of \Delta m ~ \Gamma and ~10% for a
splitting as low as \Delta m ~ 0.1\Gamma, where \Gamma is the sneutrino width.
We show that they are easily detectable already at LEP2 so long as the beam
energy is within ~10 GeV range around the muon-sneutrino masses and may
therefore serve as extremely powerful probes of sneutrino mixing phenomena.


title:
Probing Gauge-Mediated Supersymmetry Breaking Models at the Tevatron via
  Delayed Decays of the Lightest Neutralino

abstract:
  We quantitatively explore, in the context of the D0 detector at the Tevatron,
three very different techniques for observing delayed decays of the lightest
neutralino of a simple gauge-mediated supersymmetry breaking (GMSB) model to
photon plus gravitino. It is demonstrated that the delayed-decay signals
considered can greatly increase the region of general GMSB parameter space for
which supersymmetry can be detected. In the simple class of models considered,
the combination of standard supersymmetry signals and delayed-decay signals
potentially yields at least one viable signal for nearly all of the
theoretically favored parameter space. The importance, for delayed-decay signal
detection, of particular detector features and of building a simple photon
detector on the roof of the D0 detector building is studied.


title:
Modulation effect in the differential rate for Supersymmetric Dark
  Matter detection

abstract:
  The modulation effect in the direct detection of supersymmetric Cold Dark
Matter (CDM) particles is investigated. It is shown that, while normally the
modulation effect in the total event rate is small, $\leq 5% $, in some special
cases it becomes much larger. It also becomes more pronounced in the
differential event rate. It may thus be exploited to discriminate against
background.


title:
Constraints on Four Fermion Contact Interactions from Precise
  Electroweak Measurements

abstract:
  We establish constraints on a general four-fermion contact interaction from
precise measurements of electroweak parameters. We compute the one-loop
contribution for the leptonic $Z$ width, anomalous magnetic, weak-magnetic,
electric and weak dipole moments of leptons in order to extract bounds on the
energy scale of these effective interactions.


title: Probing Radiative Solar Neutrinos Decays

abstract:
  Motivated by a pilot experiment conducted by F.Vannucci et al. during a solar
eclipse, we work out the geometry governing the radiative decays of solar
neutrinos. Surprisingly, although a smaller proportion of the photons can be
detected, the case of strongly non-degenerate neutrinos brings better limits in
terms of the fundamental couplings. We advocate satellite-based experiments to
improve the sensitivity.


title: Electromagnetic Emission Rates and Spectral Sum Rules

abstract:
  The electromagnetic emission rates at SPS energies satisfy spectral
constraints in leading order in the pion and nucleon densities. These
constraints follow from the strictures of broken chiral symmetry. We saturate
these constraints using available data, leading to model independent emission
rates from a hadronic gas. With a simple fire-ball scenario, only large nucleon
densities may account for the present CERES data.


title: Electroweak Precision Physics

abstract:
  Precision measurements of electroweak observables provide stringent tests of
the Standard Model structure and an accurate determination of its parameters. A
brief overview of the present experimental status is presented. A more
extensive discussion can be found in Ref. hep-ph/9711279


title: Physics at a Muon Collider

abstract:
  I discuss the exciting prospects for exploring a wide range of new physics at
a low-energy muon collider.


title: Testing Technicolor with Scalars at the First Muon Collider

abstract:
  An interesting class of models of dynamical electroweak symmetry breaking
allows only the third generation fermions to acquire dynamical masses, such
that the masses of the first two generations should be given by coupling to a
nonstandard ``Higgs'' doublet. The scalars in this case have large couplings to
the second generation, so that they are copiously produced at a muon collider.
We analyze the potential for discovery of the neutral scalars in the
$s$-channel, and we show that at resonance there will be observed in excess of
$10^5$ events per year.


title: Two Topics in Chiral Effective Lagrangians

abstract:
  In the absence of nucleons, we use partial wave unitarity, to show that the
chiral expansion parameter must be close to $p^2/4\pi f_{\pi}^2$ rather than
$p^2/16\pi^2 f_{\pi}^2$ as previously suggested, where $p$ is a typical pion
momentum and $f_{\pi}$ the pion decay constant. When nucleons are included, we
apply the Tani-Foldy-Wouthuysen (TFW) transformation to the pion-nucleon
effective Lagrangian to obtain an expansion in powers of $1/m_N$ (inverse
nucleon mass). The results are presented up to order ${\cal O} (1/m_N^3)$,
corresponding to ${\cal O} (p^4)$ in the momentum. In this case partial
wave-unitarity is also lost in about the same range of momenta.


title:
Amplitudes and Resonances from an Energy-Dependent Analysis of pbar+p ->
  pi+pi

abstract:
  The amplitudes at a series of discrete energies obtained from a previuos
analysis of pbar+p -> pi+pi have been used as input to a global energy-
dependent analysis of data in the momentum range 360 - 1550 MeV/c. The results
confirm the previous analysis and yield refined values for meson resonance
parameters in this energy region.


title: Large Mass Expansion versus Small Momentum Expansion of Feynman Diagrams

abstract:
  The method of the large mass expansion (LME) has the technical advantage that
two-loop integrals occur only as bubbles with large masses. In many cases only
one large mass occurs. In such cases these integrals are expressible in terms
of $\Gamma$-functions, i.e. they can be handled completely analytically
avoiding even recursions and therefore this approach may find a wide field of
application. We consider it necessary to investigate the precision of this
method and test it for several two-loop vertex functions ocurring in the $Z \to
b\bar{b}$ decay by comparing it with the small momentum expansion. It turns out
that in general high order approximants have to be taken into account for a
sufficient accuracy.