title: Form Factors and QCD in Spacelike and Timelike Region

abstract:
  We analyze the basic hard exclusive processes: \pi\gamma*\gamma - transition,
pion and nucleon electromagnetic form factors, and discuss the analytic
continuation of QCD formulas from the spacelike q^2<0 to the timelike region
q^2 >0 of the relevant momentum transfers. We describe the construction of the
timelike version of the coupling constant \alpha_s. We show that due to the
analytic continuation of the collinear logarithms each eigenfunction of the
evolution equation acqiures a phase factor and investigate the resulting
interference effects which are shown to be very small. We found no sources for
the K-factor-type enhancements in the perturbative QCD contribution to the
hadronic form factors. To study the soft part of the pion electromagnetic form
factor, we use a QCD sum rule inspired model and show that there are
non-canceling Sudakov double logarithms which result in a K-factor-type
enhancement in the timelike region.


title:
QCD analysis of the diffractive structure functions measured at HERA and
  factorisation breaking at Tevatron

abstract:
  The 1994 data published by the H1 collaboration are compared with models
based on Regge phenomenology. The $x_{\PO}$ dependence of the data can be
described in a model based on the exchange of a dominant diffractive (pomeron)
trajectory with additional sub-leading reggeon contributions. The dynamics of
the Pomeron structure is studied within the framework of perturbative QCD and
new parton distributions are obtained. These parton distributions will allow a
direct test of factorisation breaking at Tevatron.


title: MSSM Higgs Sector at the One-Loop Level

abstract:
  This work provides an elementary introduction to the Higgs sector
renormalisation within the Minimal Suppersymmetric Standard Model (MSSM)
framework. The MSSM tree-level relation $m_h^2+m_H^2=m_A^2+m_Z^2$ is
renormalised using the standard technique of direct computation of the relevant
one-loop Feynman diagrams. The expected cancellation of ultraviolet divergences
is explicitly checked and the well-known leading-log term is recovered.


title: The role of secondary Reggeons in central meson production

abstract:
  We estimate the contribution of f_2 trajectory exchange to the central \eta
and \eta^\prime production. It is shown that secondary Reggeons may give a
large contribution to processes of double diffractive meson production at high
energy.


title: D^0 - D^0-bar Oscillations as a Probe of Quark-Hadron Duality

abstract:
  It is usually argued that the Standard Model predicts slow D^0-\bar D^0
oscillations with \Delta M_D, \Delta \Gamma_D < 10^{-3}*\Gamma_D$ and that New
Physics can reveal itself through \Delta M_D exceeding 10^{-3}*\Gamma_D. It is
believed that the bulk of the effect is due to long distance dynamics that
cannot be described at the quark level. We point out that in general the OPE
yields soft GIM suppression scaling only like (m_s/\mu_{hadr})^2 and even like
m_s/\mu_{hadr} rather than m_s^4/m_c^4 of the simple quark box diagram. Such
contributions can actually yield \Delta M_D, \Delta \Gamma_D \sim
O(10^{-3})*\Gamma_D without invoking additional long distance effects. They are
reasonably suppressed as long as the OPE and local duality are qualitatively
applicable in the 1/m_c expansion. We stress the importance of improving the
sensitivity on \Delta \Gamma_D as well as \Delta M_D in a dedicated fashion as
a laboratory for analyzing the onset of quark-hadron duality and comment on the
recent preliminary study on \Delta \Gamma_D by the FOCUS group.


title:
Confirmation of the $\sigma$-Meson below 1 GeV and Indication for the
  $f_0(1500)$ Glueball

abstract:
  On the basis of a simultaneous description of the isoscalar s-wave channel of
the $\pi\pi$ scattering (from the threshold up to 1.9 GeV) and of the
$\pi\pi\to K\bar{K}$ process (from the threshold to $\sim$ 1.4 GeV) in the
model-independent approach, a confirmation of the $\sigma$-meson at $\sim$ 660
MeV and an indication for the glueball nature of the $f_0(1500)$ state are
obtained.


title: The Fate of Cosmic String Zero Modes

abstract:
  Cosmic strings in realistic particle physics models have fermion zero modes
in the string core. Such zero modes change the underlying cosmology; for
example, the string can carry a current. We consider the stability of fermion
zero modes to interactions with particles in the surrounding plasma. We also
consider cosmological constraints on such theories, particulary those with a
chiral fermion zero mode, such as arises in a class of supersymmetric models.


title:
Semi-inclusive hadron-hadron transverse spin asymmetries and their
  implication for polarized DIS

abstract:
  We discuss a possible explanation of the 25 year old mystery of the large
transverse spin asymmetries found in many semi-inclusive hadron-hadron
reactions. We obtain the first reliable information about the transverse
polarized quark densities Delta_T q(x) and we find surprising implications for
the usual, longitudinal, polarized DIS. The plan of the presentation is as
follows: 1) A brief reminder about the internal structure of the nucleon. 2)
The transverse asymmetries. 3) Why it is so difficult to explain the
asymmetries. 4) Failure and then success using a new soft mechanism. 5)
implications for polarized DIS.


title: Renormalisation effects of neutrino masses and interactions

abstract:
  1. Data and implications. 2. Neutrino threshold effects. 3. Renormalisation
of the neutrino mass operator and stability properties of neutrino textures. 4.
Neutrino thresholds effects and Yukawa unification. 5. Renormalisation-induced
lepton-flavour-violating processes from non-zero neutrino masses. 6. Summary.


title:
Prospects of Detecting Baryon and Quark Superfluidity from Cooling
  Neutron Stars

abstract:
  Baryon and quark superfluidity in the cooling of neutron stars are
investigated. Observations could constrain combinations of the neutron or
Lambda-hyperon pairing gaps and the star's mass. However, in a hybrid star with
a mixed phase of hadrons and quarks, quark gaps larger than a few tenths of an
MeV render quark matter virtually invisible for cooling. If the quark gap is
smaller, quark superfluidity could be important, but its effects will be nearly
impossible to distinguish from those of other baryonic constituents.


title: Discovery of Proton Decay: A Must for Theory, a Challenge for Experiment

abstract:
  It is noted that, but for one missing piece -- proton decay -- the evidence
in support of grand unification is now strong. It includes: (i) the observed
family-structure, (ii) the meeting of the gauge couplings, (iii)
neutrino-oscillations, (iv) the intricate pattern of the masses and mixings of
all fermions, including the neutrinos, and (v) the need for $B-L$ as a
generator, to implement baryogenesis. Taken together, these not only favor
grand unification but in fact select out a particular route to such
unification, based on the ideas of supersymmetry, SU(4)-color and left-right
symmetry. Thus they point to the relevance of an effective string-unified
G(224) or SO(10)-symmetry.
  A concrete proposal is presented, within a predictive
SO(10)/G(224)-framework, that successfully describes the masses and mixings of
all fermions, including the neutrinos - with eight predictions, all in
agreement with observation. Within this framework, a systematic study of proton
decay is carried out, which pays special attention to its dependence on the
fermion masses, including the superheavy Majorana masses of the right-handed
neutrinos. The study shows that a conservative upper limit on the proton
lifetime is about (1/2 - 1)$\times10^{34}$ yrs, with $\overline{\nu}K^{+}$
being the dominant decay mode, and as a distinctive feature, $\mu^{+}K^{0}$
being prominent. This in turn strongly suggests that an improvement in the
current sensitivity by a factor of five to ten (compared to SuperK) ought to
reveal proton decay. Otherwise some promising and remarkably successful ideas
on unification would suffer a major setback.


title: What's new at small x

abstract: We discuss some recent developments in small x physics.


title: Constraints on a Parity-even/Time-Reversal-odd Interaction

abstract:
  Time-Reversal-Invariance non-conservation has for the first time been
unequivocally demonstrated in a direct measurement, one of the results of the
CPLEAR experiment. What is the situation then with regard to
time-reversal-invariance non-conservation in systems other than the neutral
kaon system? Two classes of tests of time-reversal-invariance need to be
distinguished: the first one deals with parity violating
(P-odd)/time-reversal-invariance non-conserving (T-odd) interactions, while the
second one deals with P-even/T-odd interactions (assuming CPT conservation this
implies C-conjugation non-conservation). Limits on a P-odd/T-odd interaction
follow from measurements of the electric dipole moment of the neutron. This in
turn provides a limit on a P-odd/T-odd pion-nucleon coupling constant which is
10^-4 times the weak interaction strength. Limits on a P-even/T-odd interaction
are much less stringent. The better constraint stems also from the measurement
of the electric dipole moment of the neutron. Of all the other tests,
measurements of charge-symmetry breaking in neutron-proton elastic scattering
provide the next better constraint. The latter experiments were performed at
TRIUMF (at 477 and 347 MeV) and at IUCF (at 183 MeV). Weak decay experiments
(the transverse polarization of the muon in K+ -> pi0 mu+ nu and the transverse
polarization of the positrons in polarized muon decay) have the potential to
provide comparable or possibly better constraints.


title: Flavor Gauge Bosons at the Tevatron

abstract:
  We investigate collider signals for gauged flavor symmetries that have been
proposed in models of dynamical electroweak symmetry breaking and fermion mass
generation. We consider the limits on the masses of the gauge bosons in these
models which can be extracted from Tevatron Run I data in dijet production.
Estimates of the Run II search potential are provided. We show that the models
also give rise to significant signals in single top production which may be
visible at Run II. In particular we study chiral quark family symmetry and
SU(9) chiral flavor symmetry. The Run I limits on the gauge bosons in these
models lie between (1.5-2) TeV and should increase to about 3 TeV in Run II.
Finally, we show that an SU(12) enlargement of the SU(9) model, including
leptonic interactions, is constrained by low energy atomic parity violation
experiments to lie outside the reach of the Tevatron.


title: Plasma Energy Loss into Kaluza-Klein Modes

abstract:
  Recently, Barger {\em et al.} computed energy losses into Kaluza Klein modes
from astrophysical plasmas in the approximation of zero density for the
plasmas. We extend their work by considering the effects of finite density for
two plasmon processes. Our results show that, for fixed temperature, the energy
loss rate per cm$^3$ is constant up to some critical density and then falls
exponentially. This is true for transverse and longitudinal plasmons in both
the direct and crossed channels over a wide range of temperature and density. A
difficulty in deriving the appropriate covariant interaction energy at finite
density and temperature is addressed. We find that, for the cases considered by
Barger {\em et al.}, the zero density approximation and the neglect of other
plasmon processes is justified to better than an order of magnitude.


title: Rho-omega mixing in asymmetric nuclear matter via QCD sum rule approach

abstract:
  We evaluate the operator product expansion (OPE) for a mixed correlator of
the isovector and isoscalar vector currents in the background of the nucleon
density with intrinsic isospin asymmetry [i.e. excess of neutrons over protons]
and match it with its imaginary part, given by resonances and continuum, via
the dispersion relation. The leading density-dependent contribution to
$\rho-\omega$ mixing is due the scattering term, which turns out to be larger
than any density dependent piece in the OPE. We estimate that the asymmetric
density of $n_n-n_p \sim 2.5 \times 10^{-2} ~{\rm fm^3}$ induces the amplitude
of $\rho-\omega$ mixing, equal in magnitude to the mixing amplitude in vacuum,
with the constructive interference for positive and destructive for negative
values of $n_n-n_p$. We revisit sum rules for vector meson masses at finite
nucleon density to point out the numerical importance of the screening term in
the isoscalar channel, which turns out to be one order of magnitude larger than
any density-dependent condensates over the Borel window. This changes the
conclusions about the density dependence of $m_\omega$, indicating $\sim 40$
MeV increase at nuclear saturation density.


title:
Traversing the QCD Phase Transition: Quenching Out of Equilibrium vs.
  Slowing Out of Equilibrium vs. Bubbling Out of Equilibrium

abstract:
  I review arguments for the existence of a critical point E in the QCD phase
diagram as a function of temperature T and baryon chemical potential \mu. I
describe how heavy ion collision experiments at the SPS and RHIC can discover
the tell-tale signatures of such a critical point, thus mapping this region of
the QCD phase diagram. I contrast the different ways in which the matter
produced in a heavy ion collision can be driven out of equilibrium: quenching
out of equilibrium (possible, but not guaranteed, if the transition region is
traversed at \mu << \mu_E) vs. slowing out of equilibrium (guaranteed for \mu
\sim \mu_E) vs. bubbling out of equilibrium (possible, but not guaranteed, for
\mu >> \mu_E). Quenching or bubbling create and amplify distinct, detectable,
non-gaussian fluctuations. In contrast, slowing out of equilibrium reduces the
magnitude of the specific, detectable, gaussian fluctuations which signal the
presence of the critical point.


title:
Semi-Leptonic B Meson Decays to Excited D Mesons in the Covariant
  Oscillator Quark Model

abstract:
  The spectra and branching ratios of the weak semi-leptonic B meson decays to
the first excited D mesons are predicted, taking into account the confined
effects of quarks using the covariant oscillator quark model (COQM). In the
COQM the same relation between general weak transition form factors as that in
HQET is derived, and the concrete form of the Isgur-Wise function is given with
no free parameters. Our results are somewhat different from those of other
models. The present experimental data are not sufficient for comparison.


title: Experimental Bounds on Masses and Fluxes of Nontopological Solitons

abstract:
  We have re-analyzed the results of various experiments which were not
originally interested as searches for the Q-ball or the Fermi-ball. Based on
these analyses, in addition to the available data on Q-balls, we obtained
rather stringent bounds on flux, mass and typical energy scale of Q-balls as
well as Fermi-balls. In case these nontopological solitons are the main
component of the dark matter of the Galaxy, we found that only such solitons
with very large quantum numbers are allowed. We also estimate how sensitive
future experiments will be in the search for Q-balls and Fermi-balls.


title: Effects of neutrino mixing on high-energy cosmic neutrino flux

abstract:
  Several cosmologically distant astrophysical sources may produce high-energy
cosmic neutrinos (E \geq 10^6 GeV) of all flavors above the atmospheric
neutrino background. We study the effects of vacuum neutrino mixing in three
flavor framework on this cosmic neutrino flux. We also consider the effects of
possible mixing between the three active neutrinos and the (fourth) sterile
neutrino with or without Big-Bang nucleosynthesis constraints and estimate the
resulting final high-energy cosmic neutrino flux ratios on earth compatible
with currently existing different neutrino oscillation hints in a model
independent way. Further, we discuss the case where the intrinsic cosmic
neutrino flux does not have the standard ratio.


title: Preheating with extra dimensions

abstract:
  We investigate preheating in a higher-dimensional generalized Kaluza-Klein
theory with a quadratic inflaton potential $V(\phi)=\frac12 m^2\phi^2$
including metric perturbations explicitly. The system we consider is the
multi-field model where there exists a dilaton field $\sigma$ which corresponds
to the scale of compactifications and another scalar field $\chi$ coupled to
inflaton with the interaction $\frac12 g^2\phi^2\chi^2+\tilde{g}^2\phi^3\chi$.
In the case of $\tilde{g}=0$, we find that the perturbation of dilaton does not
undergo parametric amplification while the $\chi$ field fluctuation can be
enhanced in the usual manner by parametric resonance. In the presence of the
$\tilde{g}^2\phi^3\chi$ coupling, the dilaton fluctuation in sub-Hubble scales
is modestly amplified by the growth of metric perturbations for the large
coupling $\tilde{g}$. In super-Hubble scales, the enhancement of the dilaton
fluctuation as well as metric perturbations is weak, taking into account the
backreaction effect of created $\chi$ particles. We argue that not only is it
possible to predict the ordinary inflationary spectrum in large scales but
extra dimensions can be held static during preheating in our scenario.


title: Footprints of a Broad $\sigma$(600) in Weak-Interaction Processes

abstract:
  We explore how chiral-symmetry constraints on weak-interaction matrix
elements suggest the existence of an intermediate state sigma in several
different weak-interaction processes. Particular attention is directed toward
recent evidence for a sigma within three-body nonleptonic weak decays.


title:
Two-particle correlation from a relativistic fluid with a first order
  phase transition

abstract:
  We numerically calculate two-particle correlation functions of CERN-SPS 158
  A GeV Pb+Pb central collisions based on a (3+1)-dimensional relativistic
hydrodynamics with a first order phase transition. We analyze the pair momentum
dependence of pion source sizes extracted from the
  Yano-Koonin-Podgoretski\u{\i} (YKP) parametrization which is expected to give
the source sizes directly. We find that, even in the case of the first order
phase transition, the collective expansion and surface dominant freeze-out of
the fluid naturally lead to the opaque source for which the interpretation of
the temporal source parameter as the emission duration breaks down.


title:
Impact Parameter Dependent Parton Distributions and Off-Forward Parton
  Distributions for $\zeta\to 0$

abstract:
  It is shown that off-forward parton distributions for $\zeta =0$, i.e. where
the initial and final state differ only in their transverse momenta, can be
interpreted as a simultaneous measurement of the longitudinal momentum and
transverse position (impact parameter) of partons in the infinite momentum
frame.


title: CP Violation and Dark Matter

abstract:
  A brief review is given of the effects of CP violation on the direct
detection of neutralinos in dark matter detectors. We first summarize the
current developments using the cancellation mechanism which allows for the
existence of large CP violating phases consistent with experimental limits on
the electron and on the neutron electric dipole moments in a broad class of
SUSY, string and D brane models. We then discuss their effects on the
scattering of neutralinos from quarks and on the event rates. It is found that
while CP effects on the event rates can be enormous such effects are reduced
significantly with the imposition of the EDM constraints. However, even with
the inclusion of the EDM constraints the effects are still very significant and
should be included in a precision prediction of event rates in any SUSY, string
or D brane model.


title: Production and Hadronization of Heavy Quarks

abstract:
  Heavy long-lived quarks, i.e. charm and bottom, are frequently studied both
as tests of QCD and as probes for other physics aspects within and beyond the
standard model. The long life-time implies that charm and bottom hadrons are
formed and observed. This hadronization process cannot be studied in isolation,
but depends on the production environment. Within the framework of the string
model, a major effect is the drag from the other end of the string that the c/b
quark belongs to. In extreme cases, a small-mass string can collapse to a
single hadron, thereby giving a non-universal flavour composition to the
produced hadrons. We here develop and present a detailed model for the
charm/bottom hadronization process, involving the various aspects of string
fragmentation and collapse, and put it in the context of several heavy-flavour
production sources. Applications are presented from fixed-target to LHC
energies.


title: SIMP (Strongly Interacting Massive Particle) Search

abstract:
  We consider laboratory experiments that can detect stable, neutral strongly
interacting massive particles (SIMPs). We explore the SIMP annihilation cross
section from its minimum value (restricted by cosmological bounds) to the barn
range, and vary the mass values from a GeV to a TeV. We also consider the
prospects and problems of detecting such particles at the Tevatron.


title: Heavy Quark Production and PDF's Subgroup Report

abstract:
  We present a status report of a variety of projects related to heavy quark
production and parton distributions for the Tevatron Run II.


title: Generations of Higgs Bosons in Supersymmetric Models

abstract:
  We examine extensions of the MSSM with more than one generation of Higgs
bosons. If one assumes that a symmetry eliminates the tree-level FCNC, then the
extra scalar bosons do not acquire VEVs, do not couple to fermions and do not
mix with the ordinary Higgs bosons; the lightest is absolutely stable. The two
lightest neutral scalars, $\phi_S$, and $\phi_P$, are degenerate in mass, and
the mass difference between those and the lightest charged scalar, $\phi_+$, is
calculated. For most of the parameter space, the charged scalar is between a
hundred MeV and a few GeV heavier than the neutral scalars. The $\phi_+$ will
decay at the vertex; the signature for this decay will be like that of a
chargino with a nearly degenerate undetected neutralino. Next, the possibility
that the symmetry that eliminates FCNC is a flavor symmetry is discussed. In an
example, the U(2) model, tree-level FCNC processes can be calculated in terms
of quark masses. The strongest constraint on this model is from $D-\bar{D}$
mixing, which should be within an order of magnitude of the current bound.


title:
The QCD and Standard Model Working Group: Summary Report from Les
  Houches

abstract:
  The Les Houches Workshop on Physics at TeV Colliders took place from June
8-18, 1999. One of the three working groups at Les Houches concentrated on QCD
issues, both at the Tevatron Collider and at the LHC. Besides the interest in
QCD in its own right, QCD dynamics plays an important role in the production
mechanisms for any new physics process that might be observed at either
collider, as well as any processes that may form backgrounds to the new
physics. This writeup serves both as a pedagogical overview of QCD as well as
an update on the current status of the field.


title:
Hyperon Beta-Decay and Axial Charges of the Lambda in view of Strongly
  Distorted Baryon Wave-Functions

abstract:
  Within the collective coordinate approach to chiral soliton models we suggest
that breaking of SU(3) flavor symmetry mainly resides in the baryon
wave-functions while the charge operators maintain a symmetric structure.
Sizable symmetry breaking in the wave-functions is required to reproduce the
observed spacing in the spectrum of the (1/2)^+ baryons. The matrix elements of
the flavor symmetric charge operators nevertheless yield g_A/g_V ratios for
hyperon beta-decay which agree with the empirical data approximately as well as
the successful F&D parameterization of the Cabibbo scheme. Demanding the
strangeness component in the nucleon to vanish in the two flavor limit of the
model, determines the structure of the singlet axial charge operator and yields
the various quark flavor components of the axial charge of the \Lambda-hyperon.
The suggested picture gains support from calculations in a realistic model
using pion and vector meson degrees of freedom to build up the soliton.


title:
Collider signals from slow decays in supersymmetric models with an
  intermediate-scale solution to the mu problem

abstract:
  The problem of the origin of the mu parameter in the Minimal Supersymmetric
Standard Model can be solved by introducing singlet supermultiplets with
non-renormalizable couplings to the ordinary Higgs supermultiplets. The
Peccei-Quinn symmetry is broken at a scale which is the geometric mean between
the weak scale and the Planck scale, yielding a mu term of the right order of
magnitude and an invisible axion. These models also predict one or more singlet
fermions which have electroweak-scale masses and suppressed couplings to MSSM
states. I consider the case that such a singlet fermion, containing the axino
as an admixture, is the lightest supersymmetric particle. I work out the
relevant couplings in several of the simplest models of this type, and compute
the partial decay widths of the next-to-lightest supersymmetric particle
involving leptons or jets. Although these decays will have an average proper
decay length which is most likely much larger than a typical collider detector,
they can occasionally occur within the detector, providing a striking signal.
With a large sample of supersymmetric events, there will be an opportunity to
observe these decays, and so gain direct information about physics at very high
energy scales.


title: Parametrization of polarized parton distributions

abstract:
  We report the polarized parton distributions proposed by the Asymmetry
Analysis Collaboration (AAC). Using parametrized distributions at Q^2=1 GeV^2
and measured A_1 data, we determine optimum polarized distributions in the
leading order (LO) and next-to-leading order (NLO). We find that the polarized
antiquark distribution is not well determined particularly at small x. It could
lead to a rather small quark spin content in comparison with usually-quoted
values of 10-30%. In our analysis, it varies from 5% to 28% depending on the
small-x extrapolation. It is necessary to have small-x (<10^{-3}) data for
precise determination. In addition, the large-x region should be also studied
for \Delta q-bar, which cannot be determined solely by g_1. We propose three
sets of distributions as the longitudinally polarized parton distribution
functions.


title:
Probing the MSSM Higgs Boson Sector with Explicit CP Violation through
  Third Generation Fermion Pair Production at Muon Colliders

abstract:
  We perform a systematic study of the production of a third-generation
fermion-pair, $\mu^+\mu^-\to f\bar{f}$ for $f=\tau^-,b$, and t in the minimal
supersymmetric standard model (MSSM) with explicit CP violation, which is
induced radiatively by soft trilinear interactions related to squarks of the
third generation. We classify all the observables for probing the CP property
of the Higgs bosons constructed by the initial muon beam polarization along
with the unpolarized final fermions and with the final-fermion polarization
configuration of equal helicity, respectively. The observables allow for
complete determination of CP property of the neutral Higgs bosons. The
interference between the Higgs boson and gauge boson contributions also could
provide a powerful method for the determination of the CP property of two heavy
Higgs bosons in the top-quark pair production near the energy region of the
Higgs-boson resonances. For the lightest Higgs-boson mass there is no sizable
interference between scalar and vector contributions for the determination of
the CP property of the lightest Higgs boson. We give a detailed numerical
analysis to show how the radiatively-induced CP violation in the Higgs sector
of the MSSM can be measured.


title: Soft-Gluon Angular Screening in Heavy-Quark Fragmentation

abstract:
  A method to measure the suppression of soft-gluon radiation by a heavy quark
("dead cone") is discussed. We analyse this QCD phenomenon in the framework of
the HERA experiment using Monte Carlo simulations.


title:
NLO QCD Corrections to the Polarized Photo- and Hadroproduction of Heavy
  Quarks

abstract:
  The complete details of our calculation of the NLO QCD corrections to heavy
flavor photo- and hadroproduction with longitudinally polarized initial states
are presented. The main motivation for investigating these processes is the
determination of the polarized gluon density at the COMPASS and RHIC
experiments, respectively, in the near future. All methods used in the
computation are extensively documented, providing a self-contained introduction
to this type of calculations. Some employed tools also may be of general
interest, e.g., the series expansion of hypergeometric functions. The relevant
parton level results are collected and plotted in the form of scaling
functions. However, the simplification of the obtained gluon-gluon virtual
contributions has not been completed yet. Thus NLO phenomenological predictions
are only given in the case of photoproduction. The theoretical uncertainties of
these predictions, in particular with respect to the heavy quark mass, are
carefully considered. Also it is shown that transverse momentum cuts can
considerably enhance the measured production asymmetries. Finally unpolarized
heavy quark production is reviewed in order to derive conditions for a
successful interpretation of future spin-dependent experimental data.


title:
Higher-order QED corrections to single-W production in electron-positron
  collisions

abstract:
  Four-fermion processes with a particle lost in the beam pipe are studied at
LEP to perform precision tests of the electroweak theory. Leading higher-order
QED corrections to such processes are analyzed within the framework of the
Structure Functions (SF) approach. The energy scale entering the QED SF is
determined by inspection of the soft and collinear limit of the O(alpha)
radiative corrections to the four-fermion final states, paying particular
attention to the process of single-W production. Numerical predictions are
shown in realistic situations for LEP experiments and compared with existing
results. A Monte Carlo event generator, including exact tree-level matrix
elements, vacuum polarization, higher-order leading QED corrections and
anomalous trilinear gauge couplings, is presented.


title:
Non-Perturbative Renormalization Flow in Quantum Field Theory and
  Statistical Physics

abstract:
  We review the use of an exact renormalization group equation in quantum field
theory and statistical physics. It describes the dependence of the free energy
on an infrared cutoff for the quantum or thermal fluctuations. Non-perturbative
solutions follow from approximations to the general form of the coarse-grained
free energy or effective average action. They interpolate between the
microphysical laws and the complex macroscopic phenomena. Our approach yields a
simple unified description for O(N)-symmetric scalar models in two, three or
four dimensions, covering in particular the critical phenomena for the
second-order phase transitions, including the Kosterlitz-Thouless transition
and the critical behavior of polymer chains. We compute the aspects of the
critical equation of state which are universal for a large variety of physical
systems and establish a direct connection between microphysical and critical
quantities for a liquid-gas transition. Universal features of first-order phase
transitions are studied in the context of scalar matrix models. We show that
the quantitative treatment of coarse graining is essential for a detailed
estimate of the nucleation rate. We discuss quantum statistics in thermal
equilibrium or thermal quantum field theory with fermions and bosons and we
describe the high temperature symmetry restoration in quantum field theories
with spontaneous symmetry breaking. In particular, we explore chiral symmetry
breaking and the high temperature or high density chiral phase transition in
quantum chromodynamics using models with effective four-fermion interactions.


title:
Largest temperature of the radiation era and its cosmological
  implications

abstract:
  The thermal history of the universe before the epoch of nucleosynthesis is
unknown. The maximum temperature in the radiation-dominated era, which we will
refer to as the reheat temperature, may have been as low as 0.7 MeV. In this
paper we show that a low reheat temperature has important implications for many
topics in cosmology. We show that weakly interacting massive particles (WIMPs)
may be produced even if the reheat temperature is much smaller than the
freeze-out temperature of the WIMP, and that the dependence of the present
abundance on the mass and the annihilation cross section of the WIMP differs
drastically from familiar results. We revisit predictions of the relic
abundance and resulting model constraints of supersymmetric dark matter,
axions, massive neutrinos, and other dark matter candidates, nucleosynthesis
constraints on decaying particles, and leptogenesis by decay of superheavy
particles. We find that the allowed parameter space of supersymmetric models is
altered, removing the usual bounds on the mass spectrum; the cosmological bound
on massive neutrinos is drastically changed, ruling out Dirac (Majorana)
neutrino masses $m_\nu$ only in the range 33 keV $\simlt m_\nu\simlt$ 6 (5)
MeV, which is significantly smaller from the the standard disallowed range 94
eV $\simlt m_\nu\simlt$ 2 GeV (this implies that massive neutrinos may still
play the role of either warm or cold dark matter); the cosmological upper bound
on the Peccei-Quinn scale may be significantly increased to $ 10^{16}$GeV from
the usually cited limit of about $10^{12}$GeV; and that efficient
out-of-equilibrium GUT baryogenesis and/or leptogenesis can take place even if
the reheat temperature is much smaller than the mass of the decaying superheavy
particle.


title:
Extracting |V_{ub}| from the Hadronic Mass Spectrum of Inclusive B
  decays

abstract:
  Following a strategy introduced earlier by the authors, we show that it is
possible to extract |V_{ub}| from the cut hadronic mass spectrum of B decays
without large systematic errors which usually arise from having to model the
Fermi motion of the heavy quark. We present a closed form expression for
|V_{ub}|/|V_{ts}| which is accurate up to corrections of order \alpha_s^2,
\alpha_s \rho, (\Lambda/m_b)^2/\rho, where \rho is the experimental cut
(s_c/m_b^2) on the hadronic mass used to veto charmed decays. Modulo duality
violation errors, which are intrinsic to all inclusive predictions, we estimate
the theoretical error in the extraction to be at the 5% level.


title: Geophysical constraints on mirror matter within the Earth

abstract:
  We have performed a detailed investigation of geophysical constraints on the
possible admixture of mirror matter inside the Earth. On the basis of the
Preliminary Reference Earth Model (PREM) -- the `Standard Model' of the Earth's
interior -- we have developed a method which allows one to compute changes in
various quantities characterising the Earth (mass, moment of inertia, normal
mode frequencies etc.)due to the presence of mirror matter. As a result we have
been able to obtain for the first time the direct upper bounds on the possible
concentration of the mirror matter in the Earth. In terms of the ratio of the
mirror mass to the Earth mass a conservative upper bound is $3.8\times
10^{-3}$. We then analysed possible mechanisms (such as lunar and solar tidal
forces, meteorite impacts and earthquakes) of exciting mirror matter
oscillations around the Earth centre. Such oscillations could manifest
themselves through global variations of the gravitational acceleration at the
Earth's surface. We conclude that such variations are too small to be observed.
Our results are valid for other types of hypothetical matter coupled to
ordinary matter by gravitation only (e.g. the shadow matter of superstring
theories).


title:
Oscillating Color Transparency in $\pi A\to \pi p (A-1)$ and $\gamma
  A\to \pi N (A-1)$

abstract:
  The energy dependence of $90^o$ $cm$ fixed angle scattering of $\pi p \to
\pi' p'$ and $\gamma p\to \pi^+ n$ at large momentum transfer are found to be
well described in terms of interfering short and long distance amplitudes with
dynamical phases induced by Sudakov effects. We calculate the color
transparency ratio for the corresponding processes in nuclear environments $\pi
A\to \pi'p(A-1)$ and $\gamma A\to \pi N (A-1)$ taking nuclear filtering into
account. A prediction that the transparency ratio for these reactions will
oscillate with energy provides an important test of the Sudakov phase shift and
nuclear filtering hypothesis which is testable in upcoming experiments.


title: B_c - meson sum rules at next-to-leading order

abstract:
  We present B_c-meson two-point sum rules at next-to-leading order in NRQCD
approximation. Analitycal results for perturbative spectral density and gluon
condensate contribution with account for summed Coulomb corrections are given.
Estimates of various c-quark masses together with couplings and masses of
lowest lying B_c-meson resonances are performed.


title: A Dynamical Principle For The Salpeter Equation

abstract:
  The `Salpeter Equation' which has long been known as the 3D version of the 4D
Bethe-Salpeter Equation under the Instantaneous Approximation, has a
well-defined rationale that stems from the half-century old Markov-Yukawa
Transversality Principle (MYTP) which not only effects an exact 3D reduction
from the original (4D) BS form, but also provides an equally exact
reconstruction of the 4D BS amplitude in terms of 3D ingredients. The second
aspect which is new, opens up a vista of applications to transition amplitudes
as 4D loop integrals.
  PACS: 03.65.-w ; 03.65.Co ; 11.10.Qr ; 11.10.St Keywords: Salpeter eq;
Markov-Yukawa Transversality Principle (MYTP); Covariant Instantaneity; 3D-4D
interlinkage; Vertex fn; 4D loop integrals


title:
Gluon Radiation off Hard Quarks in a Nuclear Environment: Opacity
  Expansion

abstract:
  We study the relation between the Baier-Dokshitzer-Mueller-Peigne-Schiff
(BDMPS) and Zakharov formalisms for medium-induced gluon radiation off hard
quarks, and the radiation off very few scattering centers. Based on the
non-abelian Furry approximation for the motion of hard partons in a spatially
extended colour field, we derive a compact diagrammatic and explicitly colour
trivial expression for the N-th order term of the kt-differential gluon
radiation cross section in an expansion in the opacity of the medium. Resumming
this quantity to all orders in opacity, we obtain Zakharov's path-integral
expression (supplemented with a regularization prescription). This provides a
new proof of the equivalence of the BDMPS and Zakharov formalisms which extends
previous arguments to the kt-differential cross section. We give explicit
analytical results up to third order in opacity for both the gluon radiation
cross section of free incoming and of in-medium produced quarks. The N-th order
term in the opacity expansion of the radiation cross section is found to be a
convolution of the radiation associated to N-fold rescattering and a
readjustment of the probabilities that rescattering occurs with less than N
scattering centers. Both informations can be disentangled by factorizing out of
the radiation cross section a term which depends only on the mean free path of
the projectile. This allows to infer analytical expressions for the totally
coherent and totally incoherent limits of the radiation cross section to
arbitrary orders in opacity.


title: High energy QCD and hard diffraction at HERA versus Tevatron

abstract:
  We present and discuss two different topics where Tevatron and HERA data can
be compared directly. A method allowing for a direct comparison of data with
theoretical predictions is proposed for forward jet production at HERA. An
application to the determination of the effective Pomeron intercept in the
BFKL-LO parametrization from $d\sigma/dx$ data at HERA leads to a good fit with
a significantly high effective intercept, $\alpha_P= 1.43 \pm 0.025 (stat.) \pm
0.025 (syst.)$. It is less than the value of the pomeron intercept using dijets
with large rapidity intervals obtained at Tevatron. In a second part of this
report, we make comparison between diffractive results at HERA and at Tevatron.
We first give the parton distributions in the pomeron extracted from HERA data,
and compare with hard single diffraction at Tevatron and diffractive dijets
with a leading antiproton data.


title: The three loop on-shell renormalization of QCD and QED

abstract:
  We describe a calculation of the on-shell renormalization factors in QCD and
QED at the three loop level. Explicit results for the fermion mass
renormalization factor Zm and the on-shell fermion wave function
renormalization constant Z2 are given. We find that at O(alpha_s^3) the wave
function renormalization constant Z2 in QCD becomes gauge dependent also in the
on-shell scheme, thereby disproving the ``gauge-independence'' conjecture based
on an earlier two-loop result. As a byproduct, we derive an O(alpha_s^3)
contribution to the anomalous dimension of the heavy quark field in HQET.


title: Positivity constraints and flavor dependence of higher twists

abstract:
  The positivity bound for the transverse asymmetry $A_2$ may be improved and
applied for each quark flavor separately. We use it to test the consistency of
twist-two approximation for the transverse spin-dependent ($g_T$) and the
longitudinal spin-averaged ($F_L$) structure functions. While it is satisfied
in the case of $u$ quarks, it might be violated for $d$ quarks in a region of
moderate $x$ because of its negative polarization. We attribute this
inconsistency to a stronger twist-three contribution, whose existence found by
the QCD sum rule method is a long-standing puzzle.


title: Contributions of vector-like quarks to radiative B meson decay

abstract:
  We study the decay B\to X_s\gamma in a minimal extension of the standard
model with extra up- and down-type quarks whose left- and right-handed
components are both SU(2) singlets. Constraints on the extended
Cabibbo-Kobayashi-Maskawa matrix are obtained from the experimental results for
the branching ratio. Even if the extra quarks are too heavy to be detected in
near-future colliders, the branching ratio could have a value which is
non-trivially different from the prediction of the standard model.


title: Phenomenology of Neutrino Oscillations at a Neutrino Factory

abstract:
  It is shown in the three flavor framework that neutrino factories enable us
to measure some of the oscillation parameters, such as the sign of $\Delta
m_{32}^2$, $\theta_{13}$, $\delta$. Some efforts are made to determine the
parameters (the muon energy and the neutrino path length) of a neutrino factory
to optimize the signals.


title: Neutrino oscillations in high energy cosmic neutrino flux

abstract:
  I discuss the effects of neutrino oscillations on high energy cosmic
neutrinos which come from cosmologically distant astrophysical sources. I
incorporate all the up-to-date constraints from the solar, atmospheric,
reactor, accelerator data and give the possible pattern for the ratio of the
high energy cosmic neutrinos in the cases of three and four neutrino schemes.


title:
Cosmological Gravitino Problem in Gauge-Mediated Supersymmetry Breaking
  Models

abstract:
  We investigate the cosmological gravitino problem in gauge-mediated
supersymmetry breaking models, where the gravitino becomes in general the
lightest supersymmetric particle (LSP). In order to avoid the overclosure of
the stable gravitino, the reheating temperature of inflation $T_R$ should be
low enough. Furthermore, if the gravitino mass is larger than about 100 MeV,
the decay of the next-to-LSP (NLSP) into the gravitino may modify disastrously
the abundances of the light elements predicted by the big-bang nucleosynthesis
(BBN). We consider the case in which the lighter stau is the NLSP and derive
cosmological constraints from the BBN on the stau NLSP decay. We obtain a lower
bound on the mass of stau $m_{\staul}$, which is more stringent than the
current experimental limit $m_{\staul} > 90$ GeV for the gravitino mass region
$m_{3/2} \gsim 5$ GeV. This lower bound, together with the overclosure
constraint on the stable gravitino, gives an upper bound on $T_{R}$. We find
that the reheating temperature can be as high as $10^9$--$10^{10}$ GeV for
$m_{3/2} \simeq 5$--100 GeV.


title: Quark and Lepton Mass Matrices with a Cyclic Permutation Invariant Form

abstract:
  As an attempt to give an unified description of quark and lepton mass
matrices M_f, the following mass matrix form is proposed: the form of the mass
matrices are invariant under a cyclic permutation (f_1 \to f_2, f_2 \to f_3,
f_3 \to f_1) among the fermions f_i. The model naturally leads to the maximal
mixing between \nu_\mu and \nu_\tau, and with an additional ansatz, it leads to
the well-satisfied relations |V_{us}| \simeq \sqrt{m_d/m_s} and |V_{cb}| \simeq
\sqrt{m_d/m_b}.


title:
Modelling Bose-Einstein effect from asymmetric sources in Monte Carlo
  generators

abstract:
  We present some results concerning the Bose-Einstein effect in asymmetric
sources in Monte Carlo generators. A comparison of LEP data, standard JETSET
predictions and results from the weight method is given. Possible
generalization of the weight factors to an asymmetric form is considered.


title: Quartic mass corrections to R_had at order \alpha_s^3

abstract:
  The total cross section for the production of massive quarks in electron
positron annihilation can be predicted in perturbative QCD. After expansion in
m^2/s the quartic terms, i.e. those proportional to m^4/s^2, are calculated up
to order \alpha_s^3 for vector and axial current induced rates. Predictions
relevant for charm, bottom and top quarks production are presented. The
\alpha_s^3 corrections are shown to be comparable to terms of order \alpha_s
and \alpha_s^2. As a consequence, the predictions exhibit a sizeable dependence
on the renormalization scale. The stability of the prediction is improved and,
at the same time, the relative size of the large order terms decreases by
replacing the running mass \bar{m}(\mu) with the scheme independent invariant
one \hat{m}. By combining these results with the prediction for massless case
and the quadratic mass terms the cross section for massive quark production at
electron positron colliders is put under control in order \alpha_s^3 from the
high energy region down to fairly low energies.


title: The full spin structure of quarks in the nucleon

abstract:
  We discuss bounds on the distribution and fragmentation functions that appear
at leading order in deep inelastic 1-particle inclusive leptoproduction or in
Drell-Yan processes. These bounds simply follow from positivity of the
quark-hadron scattering matrix elements and are an important guide in
estimating the magnitude of the azimuthal and spin asymmetries in these
processes. We focus on an example relevant for deep inelastic scattering at
relatively low energies.


title: Exclusive-Inclusive Ratio of Semileptonic Lambda_b-Decays

abstract:
  We present theoretical evidence that the exclusive/inclusive ratio of
semileptonic $\Lambda_b$-decays exceeds that of semileptonic B-decays where the
experimental exclusive/inclusive ratio amounts to about 66%. We start from the
observation that the spectator quark model provides a lower bound on the
leading order Isgur-Wise function of the $\Lambda_b \to \Lambda_c$ transition
in terms of the corresponding $B \to D,D^*$ mesonic Isgur-Wise function. Using
experimental data for the $B \to D,D^*$ mesonic Isgur-Wise functions this bound
is established. Applying a Bethe-Salpeter model including spectator quark
interactions and a QCD sum rule estimate of the $\Lambda_b \to \Lambda_c$
transition form factor which satisfy the spectator quark model bound we predict
the exclusive/inclusive ratio of semileptonic $\Lambda_b$ decay rates to lie in
a range between 0.81 and 0.92. We also provide an upper bound on the baryonic
Isgur-Wise function which is determined from the requirement that the exclusive
rate should not exceed the inclusive rate.


title: Summary of the SUSY Working Group of the 1999 Les Houches Workshop

abstract:
  The results obtained by the Working Group on Supersymmetry at the 1999 Les
Houches Workshop on Collider Physics are summarized. Separate chapters treat
"general" supersymmetry, R-parity violation, gauge mediated supersymmetry
breaking, and anomaly mediated supersymmetry breaking.


title: Renormalization of quark axial current in the chiral potential model

abstract:
  Non-conserved composite operators like the quark axial current have divergent
matrix elements therefore must be renormalized. We explore how this can be done
in quark model calculations where the systematic procedure of dimensional
regularization and minimal subtraction is not applicable. We propose a most
natural and convenient regularization scheme of cutting the intermediate quark
states over which we sum in loop diagram calculations at a certain energy. We
show that this scheme works perfectly for the quark axial current and we obtain
the quark spin contribution to the proton spin: $\Delta_u=0.82$,
$\Delta_d=-0.43$, $\Delta_s=-0.10$, which is in excellent agreement with
experiments.


title: Predictions for Decays of Radially Excited Baryons

abstract:
  We consider the strong decays of the lowest-lying radially excited baryons,
in SU(6) language the states comprising the first excited 56-plet. Assuming a
single-quark decay approximation, and negligible configuration mixing, we make
model-independent predictions for the partial decay widths to final states with
a single meson. Masses of unobserved states are predicted using results from
large-N_c QCD, and the momentum dependence of the one-body decay amplitude is
determined phenomenologically by fitting to observed decays, so that the baryon
spatial wave functions are not assumed. We point out that comparison of these
predictions to experiment may shed light on whether the Roper resonance can be
consistently interpreted as a three-quark state.


title:
The decays $\bar{B}\to \bar{K}D$ and $\bar{B}\to \bar{K}\bar{D}$ and
  final state interactions

abstract:
  The decays $\bar{B}\to \bar{K}D$ and $\bar{B}\to \bar{K}\bar{D}$ taking into
account final state interactions are discussed. These decays are described by
four strong phases $\delta_0, \delta_1, \tilde{\delta}_0, \tilde{\delta}_1$
(subscript 0 and 1 refer to I=0 and I=1 isospin final states), one weak phase
$\gamma $ and four real amplitudes. Isospin constraints are taken into account.
It is argued that strong interaction dynamics gives $\delta_1\approx
\tilde{\delta}_1$. The four real amplitudes are estimated. Some observable
consequences are discussed.


title: Solving the Hierarchy Problem in Two-Brane Cosmological Models

abstract:
  We analyze cosmological solutions in the class of two-brane models with
arbitrary tensions which contain matter with general equations of state. We
show that the mass hierarchy between the two branes is determined by the ratio
of the lapse functions evaluated on the branes. This ratio can be sufficiently
small without fine-tuning the brane separation, once the transverse dimension
is stabilized. For suitably large interbrane separations, both brane tensions
are positive. We also find that the cosmological evolution obeys the standard
four-dimensional Friedman equation up to small corrections.


title: Zee-type Neutrino Mass Matrix and Bi-Maximal Mixing

abstract:
  It is shown that the bi-maximal solution is the only possibility to reconcile
Zee-type neutrino mass matrix with three flavors to the current atmospheric and
solar neutrino experimental data. The mass of the lightest neutrino, which
consist mostly of $\nu_{\mu}$ and $\nu_{\tau}$, is $\simeq \Delta
m_{\odot}^2/(2\sqrt{\Delta m_{atm}^2})$. The related topics on Zee-type
neutrino mass matrix are also discussed.


title: Neutrinos: How Do They Mix and Violate CP ?

abstract:
  We discuss a simple model of lepton mixing and CP violation based on the
flavor democracy of charge leptons and the mass degeneracy of neutrinos. A
nearly bi-maximal flavor mixing pattern, which is favored by current data on
atmospheric and solar neutrino oscillations, emerges naturally from this model
after explicit symmetry breaking. The rephasing-invariant strength of CP or T
violation can be as large as one percent, leading to significant probability
asymmetries between \nu_\mu \to \nu_e and \bar{\nu}_\mu \to \bar{\nu}_e (or
\nu_e \to \nu_\mu) transitions in the long-baseline neutrino experiments. The
possible matter effects on CP- and T-violating asymmetries are also taken into
account.


title: Pair production of doubly heavy baryons

abstract:
  We analytically calculate the total and differential cross sections for the
pair production of doubly heavy baryons in the framework of diquark model. The
processes of electron-positron and quark-antiquark annihilations are
considered. The fractions of doubly heavy baryons in the yields of heavy quarks
are evaluated numerically.


title:
Parity-violating electromagnetic interactions in QED_3 at finite
  temperature

abstract:
  We study the parity-breaking terms generated by the box diagram in 2+1
dimensional thermal QED. These lead, in the long wave limit, to a gauge
invariant extensive action which behaves as 1/T at high temperature. In
contrast, the effective action in the static limit involves leading
non-extensive terms proportional to 1/T^3 at high temperature, which violate
large gauge invariance. We derive a non-linear large gauge Ward identity, which
relates the leading static terms of different order in perturbation theory and
whose solution coincides with the all order effective action proposed earlier.


title: Measurement of Higgs Properties at the LHC

abstract:
  A SM-like Higgs boson can be produced in a variety of channels at the LHC. By
combining information from production via gluon fusion and weak boson fusion,
various partial widths and the total Higgs boson width can be extracted.
Expected accuracies for 200 fb^{-1} of data are in the 10% range.


title: Instanton-induced Effects in QCD High-Energy Scattering

abstract:
  We evaluate a number of new instanton-induced phenomena in QCD, starting with
static dipole-dipole potentials, and proceeding to quark-quark and
dipole-dipole scattering at high energy. We use a non-perturbative formulation
of the scattering amplitude in terms of a correlator of two Wilson-lines
(quarks) or Wilson-loops (dipoles) and analyze the Euclidean amplitudes with
both perturbative gluons and instantons. The results are analytically continued
to Minkowski geometry, by interpreting the angle between the Wilson lines as
rapidity. We discuss the relevance of our results for the phenomenology of
near-forward hadronic processes at high energy, especially for processes with
multiple color exchanges.


title:
Isospin Breaking in the Extraction of Isovector and Isoscalar Spectral
  Functions from e^+e^- --> hadrons

abstract:
  A finite energy sum rule (FESR) analysis of the isospin-breaking vector
current correlator <0|T(V^3_\mu V^8_\nu)|0> is used to determine the
isospin-breaking electromagnetic (EM) decay constants of the low-lying vector
mesons. These results are used to evaluate the corrections required to extract
the flavor diagonal 33 and 88 resonance contributions from the full resonance
EM contributions to the EM spectral function. A large (~15%) correction is
found in the case of the omega contribution to the isoscalar spectral function.
The implications of these results for sum rules based on the
isovector-isoscalar spectral difference are considered.


title:
Neutralino Proton Cross Sections For Dark Matter In SUGRA And D-BRANE
  Models

abstract:
  Neutralino proton cross sections are examined for models with R-parity
invariance with universal soft breaking (mSUGRA) models, nonuniversal SUGRA
models, and D-brane models. The region of parameter space where current dark
matter detectors are sensitive, i.e. $1\times 10^{-6}$ pb, is examined. For
mSUGRA models, detectors are sampling parts of the parametr space for tan$\beta
>\sim 25$. The nonuniversal models can achieve cross sections that are a factor
of 10-100 bigger or smaller then the universal one and in the former case
sample regions tan$\beta >\sim 4$. The D-brane models considered require
tan$\beta >\sim 15$. The inclusion of CP violating phases reduces the cross
section by a factor of $\sim$ 2-3 (but also requires considerable fine tuning
at the GUT scale). The expected particle spectra at accelerators are examined
and seen to differ for each model. Three new regions of possible coannihilation
are noted.


title: Scalar Meson Decay Constants and the Nature of the a_0(980)

abstract:
  The a_0(980), a_0(1450) and K_0(1430) decay constants are determined using a
form of QCD sum rules known to produce a very accurate determination of the rho
decay constant. The ratio of a_0(980) to K_0(1430) decay constants is shown to
be ~0.6, ruling out both the ``loosely-bound-K\bar{K}-molecule'' and Gribov
minion scenarios for the a_0(980). Solutions for the isovector scalar spectral
function obtained in the literature from sum rule analyses employing a more
restrictive single-resonance-plus-continuum form of the input spectral ansatz,
are also investigated. These solutions, which suggest, in contrast to the
present results, negligible coupling of the a_0(980) to the isovector scalar
density are shown to produce a poor quality match between the OPE and hadronic
sides of the sum rules employed here, and hence to be strongly disfavored
relative to the present solution.


title: The Strange Quark Mass From Flavor Breaking in Hadronic Tau Decays

abstract:
  The strange quark mass is extracted from a finite energy sum rule (FESR)
analysis of the flavor-breaking difference of light-light and light-strange
quark vector-plus-axial-vector correlators, using spectral functions determined
from hadronic tau decay data. We point out problems for existing FESR
treatments associated with potentially slow convergence of the perturbative
series for the mass-dependent terms in the OPE over certain parts of the FESR
contour, and show how to construct alternate weight choices which not only cure
this problem, but also (1) considerably improve the convergence of the
integrated perturbative series, (2) strongly suppress contributions from the
region of s values where the errors on the strange current spectral function
are still large and (3) essentially completely remove uncertainties associated
with the subtraction of longitudinal contributions to the experimental decay
distributions. The result is an extraction of m_s with statistical errors
comparable to those associated with the current experimental uncertainties in
the determination of the CKM angle, V_{us}. We find m_s(1 GeV)=158.6\pm 18.7\pm
16.3\pm 13.3 MeV (where the first error is statistical, the second due to that
on V_{us}, and the third theoretical).


title: Photoproduction of top in peripheral heavy ion collisions

abstract:
  In relativistic heavy ion collisions, top quarks can be produced by
photon-gluon fusion when a photon from the Weizs\"acker-Williams virtual photon
field of one nucleus interacts with a gluon in the other nucleus.
Photoproduction with heavy ions at the Large Hadron Collider (LHC) will be the
first accessible non-hadronic top production channel. We calculate the $t \bar
t$ photoproduction cross sections, pair mass and top quark rapidity
distributions in peripheral heavy ion collisions. The cross sections are
sensitive to the top quark charge and the large-$Q^2$ gluon distribution in the
nucleus. We find a cross section of 94 pb in calcium-calcium collisions,
leading to 190 pairs in a one month ($10^6$ sec) LHC run. We also find $p$Pb
and $p$Ca cross sections of 5.8 and 3.4 pb respectively, resulting in 6 and 34
$t\bar t$ pairs per month.


title: Weighing the universe with accelerators and detectors

abstract:
  Suppose the lightest superpartner (LSP) is observed at colliders, and WIMPs
are detected in explicit experiments. We point out that one cannot immediately
conclude that cold dark matter (CDM) of the universe has been observed, and we
determine what measurements are necessary before such a conclusion is
meaningful. We discuss the analogous situation for neutrinos and axions; in the
axion case we have not found a way to conclude axions are the CDM even if
axions are detected.


title: Flavour Violation in SUSY SU(5) GUT at Large tan beta

abstract:
  We study flavour violation in the minimal SUSY SU(5) GUT assuming all the
third generation Yukawa couplings to be due to the renormalizable physics above
GUT scale. At large $\tan\beta,$ as suggested by Yukawa unification in SU(5),
sizable flavour violation in the left (right) slepton (down squark) sector is
induced due to renormalization effects of down type Yukawa couplings between
GUT and Planck scales in addition to the flavour violation in the right slepton
sector. The new flavour physics contribution to $K-\bar K,$ $B-\bar B$ mixing
is small but might be of phenomenological interest in the case of $b\to
s\gamma.$ The sign of the latter contribution is the same as the sign of the
dominant chargino contribution, thus making the constraints on SUSY scale
coming from $b\to s\gamma$ somewhat more restrictive. The most important
feature of the considered scenario is the large rate of lepton flavour
violation. Given the present experimental constraints, the $\mu\to e\gamma$ and
$\mu-e$ conversion branching ratios are above the sensitivity of the planned
experiments unless the SUSY scale is pushed above one TeV.


title:
Proton and neutron charge form factors in soliton model with
  dilaton-quarkonium field

abstract:
  Nucleon electromagnetic form factors are considered in the framework of the
generalized Skyrme model with dilaton-quarkonium field. In our recent
publication we have got big discrepancies between calculated form factors and
dipole approximation formula. Here we have reasonably good accordance between
them in finite impulse region after vector meson dominance have been taken into
account. Omega and Rho -meson have been included into only hadron structure of
the photon.


title:
Effective Lagrangian induced by the anomalous Wess-Zumino action and the
  exotic resonance state with $I^G(J^{PC})=1^-(1^{-+})$ in the $\rho\pi$,
  $\eta\pi$, $\eta'\pi$, and $K^*\bar K+\bar K^*K$ channels

abstract:
  A simple model for the exotic waves with $I^G(J^{PC})=1^-(1^{-+})$ in the
reactions $VP\to VP$, $VP\to PP$, and $PP\to PP$ is constructed beyond the
scope of the quark-gluon approach. The model satisfies unitarity and
analyticity and uses as a "priming" the "anomalous" nondiagonal $VPPP$
interaction which couples together the four channels $\rho\pi$, $\eta\pi$,
$\eta'\pi$, and $K^*\bar K+\bar K^*K$. The possibility of the resonancelike
behavior of the $I^G(J^{PC})=1^-(1^{-+})$ amplitudes belonging to the $\{10\}-
\{\bar{10}\}$ and $\{8\}$ representations of SU(3) as well as their mixing is
demonstrated explicitly in the $1.3-1.6$ GeV mass range which, according to the
current experimental evidence, is really rich in exotics.


title: Q-ball collisions in the MSSM: gauge-mediated supersymmetry breaking

abstract:
  Collisions of non-topological solitons, Q-balls, are considered in the
Minimal Supersymmetric Standard Model where supersymmetry has been broken at a
low energy scale via a gauge mediated mechanism. Q-ball collisions are studied
numerically on a two dimensional lattice for a range of Q-ball charges. Total
cross-sections, as well as fusion and geometrical cross-sections are
calculated. The total and geometrical cross-sections appear to converge with
increasing charge. The fusion cross-section has been estimated to be larger
than 60% of the geometrical cross-section for large balls.


title:
Charge and Transition Form Factors of Light Mesons with Light-Front
  Quark Model

abstract:
  The charge and transition form factors of pion ($F_\pi$, $F_{\pi\gamma}$, and
$F_{\pi\gamma^*}$) are studied with the light-front quark model. We find that
our results for $F_\pi$ and $F_{\pi\gamma}$ agree very well with experimental
data. Furthermore, the decay constants of $\eta$ and $\eta'$ are evaluated. We
also calculate $F_{\eta\gamma}$ and $F_{\eta'\gamma}$ and compare with the
experimental data.


title:
The radiative decay phi - gamma pi pi in a coupled channel model and the
  structure of f0(980)

abstract:
  A coupled channel model is used to study the nature of the scalar mesons
produced in the decay phi - gamma pi pi. The KKbar molecular picture of f0(980)
is found to be in a good agreement with the recent experimental data from SND
and CMD-2. The structure of the light scalar mesons is elucidated by
investigating the S-matrix poles and the qqbar spectral density.


title:
On the Use of Transverse Momentum Spectra to probe Thermalisation and
  Collective Expansion in Relativistic Nucleus-Nucleus Collisions

abstract:
  Transverse momentum spectra of the reaction products from proton-proton and
nucleus-nucleus collisions are discussed within the phenomenological frameworks
of statistical phase-space and string fragmentation models. It will be shown
that a string fragmentation model can accommodate all of the observations
discussed here and consequently it is claimed that no conclusion about the
thermal nature or collective expansion of the created system may be derived
from observed transverse momentum spectra.


title: Scalar Electrodynamics in Framework of Randall-Sundrum Model

abstract:
  Considering the Randall-Sundrum background, we calculate the total
cross-section for $\phi\phi ^\star \to G \gamma$ in the framework of the scalar
electrodynamics.


title:
GENIUS project, neutrino oscillations and Cosmology: neutrinos reveal
  their nature?

abstract:
  The neutrinoless double beta decay as well as any other laboratory experiment
has not been able to answer the question of the neutrino's nature. Hints on the
answer are available when neutrino oscillations and $(\beta\beta)_{0 \nu}$ are
considered simultaneously. In this case phenomenologically interesting neutrino
mass schemes can lead to non-vanishing and large values of $<m_{\nu}>$. As a
consequence, some schemes with Majorana neutrinos can be ruled out even now. If
we assume that in addition neutrinos contribute to Hot Dark Matter then the
window for Majorana neutrinos is even more restricted, e.g. GENIUS experiment
will be sensitive to scenarios with three Majorana neutrinos.


title: Limits on the Mass of a Composite Higgs Boson

abstract:
  We discuss the bound on the mass of the Higgs boson arising from precision
electroweak measurements in the context of the triviality of the scalar Higgs
model. We show that, including possible effects from the underlying nontrivial
dynamics, a Higgs boson mass of up to 500 GeV is consistent with current data.


title:
What we know about the Theoretical Foundation of Duality in Electron
  Scattering

abstract:
  We consider some of the things that we understand about the theoretical
underpinnings of duality, including items such as why the resonance
peak/background ratio is constant in general, why it falls for the
$\Delta(1232)$, what we might expect for scaling and duality with longitudinal
or spin-dependent structure functions, and what kind of scaling or duality we
might expect for semiexclusive processes.


title: Testing CP Violation in the Higgs Sector at Muon Colliders

abstract:
  We study the possibility of measuring the muon Yukawa couplings in s-channel
Higgs boson production at a muon collider with transversely polarized beams. We
investigate sensitivity to the relative size of the CP-odd and CP-even muon
Yukawa couplings. Provided the event rate observed justifies the operation of
the mu+mu- Higgs boson factory, we find that 40% polarization for both beams is
sufficient to resolve the CP nature of a single resonance as well as
disentangle it from two overlapping CP conserving resonances.


title: Neutralino dark matter vs galaxy formation

abstract:
  Neutralino dark matter may be incompatible with current cold dark matter
models with cuspy dark halos, because excessive synchrotron radiation may
originate from neutralino annihilations close to the black hole at the galactic
center.


title:
Spin structure and longitudinal polarization of hyperon in e+e-
  annihilation at high energies

abstract:
  Longitudinal polarizations of different kinds of hyperons produced in e+e-
annihilation at LEP I and LEP II energies in different event samples are
calculated using two different pictures for the spin structure of hyperon: that
drawn from polarized deep inelastic lepton-nucleon scattering data or that
using SU(6) symmetric wave functions. The result shows that measurements of
such polarizations should provide useful information to the question of which
picture is more suitable in describing the spin effects in the fragmentation
processes.


title:
SNO and the neutrino magnetic moment solution of the solar neutrino
  problem

abstract:
  Assuming that the solar neutrino deficit observed in the Homestake, SAGE,
Gallex, Kamiokande and Super-Kamiokande experiments is due to the interaction
of the neutrino transition magnetic moment with the solar magnetic field, we
calculate the expected values of a number of observables to be measured by SNO.
For three model solar magnetic field profiles that produce the best fits of the
previous data we calculate the charged current event rate, the (neutral
current)/(charged current) event ratio and the charged current electron
spectrum as well as its first and second moments. We study the dependence of
the calculated observables on the choice of the magnetic field profile and on
the value of the solar $hep$ neutrino flux. We also compare our results with
those obtained assuming that the solar neutrino problem is due to neutrino
oscillations in vacuum or in matter. We show that there is an overlap or
partial overlap between our predictions and those found for each of the
oscillation solutions (SMA, LMA, LOW and VO). Given the uncertainties in the
calculations and the expected uncertainties in the experimental results, the
unambiguous discrimination between the two types of solutions to the solar
neutrino problem (neutrino oscillations and magnetic moments) on the basis of
the average rates and electron spectrum distortions appears to be difficult.
The possible time dependence of the charged current signal and spectrum
distortion in the case of the magnetic moment solution therefore remains the
best hope for such a discrimination. For a hybrid solution (neutrino magnetic
moment plus flavour mixing) the smoking gun signature would be an observation
of $\bar{\nu}_e$'s from the sun.


title: Relic Abundances and the Boltzmann Equation

abstract:
  I discuss the validity of the quantum Boltzmann equation for the calculation
of WIMP relic densities.


title: Relativistic Coulomb Resummation in QCD

abstract:
  A relativistic Coulomb-like resummation factor in QCD is suggested, based on
the solution of the quasipotential equation.


title:
Pion Lattices in HI Transverse Phase Space and Sudden Traversal of the
  QCD Phase Boundary

abstract:
  Correlation data from high-energy p-p collisions indicate substantial
anticorrelation of like-sign pions and correlation of unlike-sign pions on
rapidity and azimuth at small length scale suggesting approach to a 1D lattice
structure during string hadronization. I generalize this result to propose that
an {\em incipient} 3D pion lattice structure may be formed during hadronization
of a QGP. I then present a method to detect this structure in the transverse
phase space of heavy-ion collisions which depends on local transverse Hubble
flow. I also relate this correlation structure to recently proposed suppression
of net charge and baryon-number fluctuations on rapidity after sudden traversal
of the QCD phase boundary.


title: Electromagnetic radiation of baryons containing two heavy quarks

abstract:
  The two heavy quarks in a baryon which contains two heavy quarks and a light
one, can constitute a scalar or axial vector diquark. We study electromagnetic
radiations of such baryons, (i) \Xi_{(bc)_1} -> \Xi_{(bc)_0}+\gamma, (ii)
\Xi_{(bc)_1}^* -> \Xi_{(bc)_0}+\gamma, (iii) \Xi_{(bc)_0}^{**}(1/2, l=1) ->
\Xi_{(bc)_0}+\gamma, (iv) \Xi_{(bc)_0}^{**}(3/2, l=1) -> \Xi_{(bc)_0}+\gamma
and (v) \Xi_{(bc)_0}^{**}(3/2, l=2) -> \Xi_{(bc)_0}+\gamma, where
\Xi_{(bc)_{0(1)}}, \Xi^*_{(bc)_1} are S-wave bound states of a heavy scalar or
axial vector diquark and a light quark, and \Xi_{(bc)_0}^{**}(l is bigger than
1) are P- or D-wave bound states of a heavy scalar diquark and a light quark.
Analysis indicates that these processes can be attributed into two categories
and the physical mechanisms which are responsible for them are completely
distinct. Measurements can provide a good judgment for the diquark structure
and better understanding of the physical picture.


title: Mass Hierarchy from SU(1,1) Horizontal Symmetry

abstract:
  The new mechanism for the generation of the chiral generations is proposed
based on the SU(1,1) horizontal gauge symmetry. The appearance of the chiral
generations is controlled by the coupling constant s of the model. This is
crucial in the grand unification scheme. The resulting chiral generations
naturally acquire the hierarchal Yukawa coupli ng matrices. Propriety of the
model to the observed hierarchical structure is discussed nume rically under
the minimal parameter set.


title: Democratic-type neutrino mass matrix

abstract:
  We consider the democratic-type neutrino mass matrix and show that this
matrix predicts the atmospheric neutrino mixing to be almost maximal, $\sin^2
2\theta_{atm}>0.999$ as well as the large CP violation (the CP violation phase
in the standard form is maximal $\delta=\pi/2$). We construct the $Z_3$
symmetric dimension five effective Lagrangian with two up-type Higgs doublets
and show that this Lagrangian leads to the democratic neutrino mass matrix.
Furthermore, we consider the restricted model with one up-type Higgs doublet
and obtain the prediction, $0.87<\sin^2 2\theta_{sol}<8/9$.


title: The Chiral Fermion Meson Model at Finite Temperature

abstract:
  We study the chiral fermion meson model which is the well known linear sigma
model of Gell-Mann-and-Levy at finite temperature.A modified self-consistent
resummation (MSCR) which resums higher order terms in the perturbative
expansion is proposed. It is shown that with the MSCR the problem of tachyonic
masses is solved, the renormalization of the gap equations is carried out and
the Goldstone's theorem is verified. We also apply the method to investigate
another known case at high temperature and compare with results found in the
literature.


title: Lessons from CLEO and FOCUS Measurements of D0-anti-D0 Mixing Parameters

abstract:
  If the true values of the D0-anti-D0 mixing parameters lie within the one
sigma ranges of recent measurements, then there is strong evidence for a large
width difference, y > 0.01, and large SU(3) breaking effects in strong phases,
\delta > pi/4. These constraints are model independent, and would become
stronger if M_{12}/Gamma_{12} << 1 in the D0-anti-D0 system. The interesting
fact that the FOCUS result cannot be explained by a large mass difference is
not trivial and depends on the small D0-anti-D0 production asymmetry in FOCUS
and the bounds on CP violating effects from CLEO. The large value of \delta
might help explain why y ~ sin^2(theta_c).


title: Quintessential Vanishing of the Cosmological Constant

abstract:
  We consider an effective field theory description of gravity coupled to a
scalar field with volume-preserving diffeomorphism and Weyl invariances. The
smallness of the cosmological constant is achieved when the potential of the
scalar is extremely flat. This implies a possible relationship between the
smallness and the quintessential sector of the cosmological constant.


title:
Two-Loop QCD Anomalous Dimensions of Flavour-Changing Four-Quark
  Operators Within and Beyond the Standard Model

abstract:
  We calculate the two-loop QCD anomalous dimension matrix (ADM) gamma^(1)_NDR
in the NDR-MSbar scheme for all the flavour-changing four-quark dimension-six
operators that are relevant in both the Standard Model and its extensions. Both
current-current and penguin diagrams are included. Some of our NDR-MSbar
results for Delta F=1 operators overlap with the previous calculations, but
several others have never been published before. In the case of Delta F=2
operators, our results are compatible with the ones obtained by Ciuchini et al.
in the Regularization-Independent renormalization scheme, but differ from their
NDR-MSbar results. In order to explain the difference, we calculate the ADM of
Delta F=2 operators again, extracting it from the ADM of Delta F=1 operators.


title: Rigorous Effective Field Theory Study on Pion Form Factor

abstract:
  We study $e^+e^-\to\pi^+\pi^-$ cross section and phase shift of $I=l=1$
$\pi-\pi$ scattering below 1GeV in framework of chiral constituent quark model.
The results including all order contribution of the chiral perturbation
expansion and all one-loop effects of pseudoscalar mesons, but without any
adjust parameters. Width of $\rho$ predicted by the model strongly depends on
transition momentum-square $q^2$. We show that the mass pamameter of
$\rho$-meson in its propagator is very different from its physical mass due to
momentum-dependent width of $\rho$. The mass difference between $\rho^0$ and
$\omega$ are predicted successfully. The rigorous theoretical prediction on
$e^+e^-\to\pi^+\pi^-$ cross section and the phase shift in $I=l=1$ $\pi-\pi$
scattering agree with data excellentlly.


title: Massive Ghosts in Softly Broken SUSY Gauge Theories

abstract:
  It is shown that, due to soft supersymmetry breaking in gauge theories within
the superfield formalism, there appears the mass for auxiliary gauge fields. It
enters into the RG equations for soft masses of physical scalar particles and
can be eliminated by solving its own RG equation. Explicit solutions up to the
three-loop order in the general case and in the MSSM are given. The
arbitrariness in choosing the initial condition is discussed.


title: Naturalness Reach of the Large Hadron Collider in Minimal Supergravity

abstract:
  We re-analyse the prospects of discovering supersymmetry at the LHC, in order
to re-express coverage in terms of a fine-tuning parameter and to extend the
analysis to scalar masses (m_0) above 2 TeV.
  We use minimal supergravity (mSUGRA) unification assumptions for the SUSY
breaking parameters. The discovery reach at high m_0 is of renewed interest
because this region has recently been found to have a focus point, leading to
relatively low fine-tuning, and because it remains uncertain how much of the
region can be ruled out due to lack of radiative electroweak symmetry breaking.
  The best fine tuning reach is found in a mono-leptonic channel, where for
mu>0, A_0=0 and tan beta=10
  (within the focus point region), and a top mass of 174 GeV, all points in
mSUGRA with m_0 < 4000 GeV, with a fine tuning measure up to 210 (500) are
covered by the search, where the definition of fine-tuning excludes (includes)
the contribution from the top Yukawa coupling. Even for arbitrarily high m_0,
mSUGRA can be discovered through gaugino events, provided the gaugino mass
parameter M_1/2 < 460 GeV. In this region, the mono-leptonic channel still
provides the best reach.


title:
Confidence Intervals and Upper Bounds for Small Signals in the Presence
  of Background Noise

abstract:
  We discuss a new method for setting limits on small signals in the presence
of background noise. The method is based on a combination of a two dimensional
confidence region and the large sample approximation to the likelihood ratio
test statistic. It automatically quotes upper limits for small signals and
two-sided confidence intervals for larger samples. We show that this method
gives the correct coverage and also has good power.


title: The impact of LEP 2 data on possible anomalous enhancements of Re e'/e

abstract:
  It has been shown in the past that the real part of the e'/e ratio is
particularly sensitive to anomalous gauge couplings that modify the Standard
Model Lagrangian. Due to the loose bounds on these couplings coming from low
energy processes and to the poor sensitivity of hadron colliders to couplings
such as $\Delta g_Z$, it has been argued that anomalous couplings could still
produce an enhancement of Re e'/e bringing this observable closer to the
experimental value obtained by KTeV, NA31 and NA48. The impact of the new
measurements done at LEP2 in these years is discussed and new severe
constraints to this hypothesis are determined.


title: epsilon'/epsilon in the Chiral Limit

abstract:
  The $K\to\pi\pi$ system is analyzed in the chiral limit within the Standard
Model. We discuss how to connect the short-distance running in the $|\Delta
S|=1$ case to the matrix-elements calculated in a low-energy approximation in a
scheme-independent fashion. We calculate this correction and the resulting
Wilson Coefficients. The matrix elements are calculated to next-to-leading
order in the $1/N_c$ expansion and combined with the Wilson coefficients to
calculate the two isospin amplitudes and $\epsilon_K^\prime$. The $\Delta
I=1/2$ rule is reproduced within expected errors and we obtain a substantially
larger value for $\epsilon_K^\prime/\epsilon_K$ than most other analysises. We
discuss the reasons for this difference. We also suggest that the $X$-boson
method is an option for lattice QCD calculations.


title:
Covariant Quark-Representation of Composite Meson Systems and Chiral
  Symmetry

abstract:
  Assuming the spin-independence for confining force, we give a covariant quark
representation of general composite meson systems with definite Lorentz
transformation properties. For benefit of this representation we are able to
deduce automatically the transformation rules of composite mesons for general
symmetry operations from those of constituent (exciton) quarks. Applying this
we investigate especially physical implication of chiral symmetry for the meson
systems, and point out a possibility of existence of new meson multiplets.


title:
Low-energy Limits on the Antisymmetric Tensor Field Background on the
  Brane and on the Non-commutative Scale

abstract:
  A non-vanishing vacuum expectation value for an antisymmetric tensor field
leads to the violation of Lorentz invariance on the brane. This violation is
controlled by the $\theta_{\mu \nu}$ parameter, which has a dimension of
inverse mass squared. We assume that the zeroth order term in theta-expansion
represents the Standard Model and study the effects induced by linear terms in
theta_{\mu\nu}. Low-energy precision experiments place the limit on the
possible size of this background at the level of $1/\sqrt{\theta} > 5 \times
10^{14}$ GeV. This poses certain difficulty for the TeV-range string scale
models, in which the antisymmetric field has to acquire a relatively large mass
to ensure that $\theta_{\mu \nu}=0$ and avoid cosmological moduli problem.


title: Neutrino self-energy in a magnetized medium in arbitrary $\xi$-gauge

abstract:
  We calculate the one-loop neutrino self-energy in a magnetized plasma to all
orders in the magnetic field. The calculation is done in a general gauge. We
obtain the dispersion relation and effective potential for neutrinos in a
CP-symmetric plasma under various conditions, and show that, while the
self-energy depends on the gauge parameter $\xi$, the dispersion relation and
effective potential to leading order are independent of it.


title: Absence of Gluonic Components in Axial and Tensor Mesons

abstract:
  A quarkonium-gluonium mixing scheme previously developed to describe the
characteristic of the pseudoscalar mesons is applied to axial and tensor
mesons. The parameters of the model are determined by fitting the eigenvalues
of a mass matrix. The corresponding eigenvectors give the proportion of light
quarks, strange quarks and glueball in each meson. However the predictions of
the model for branching ratios and electromagnetic decays are incompatible with
the experimental results. These results suggest the absence of gluonic
components in the states of axial and tensor isosinglet mesons analyzed here.


title: Two photon background for Higgs boson searches at the LHC

abstract:
  The search for an intermediate mass Higgs boson at the LHC needs the
quantitative understanding of the two-photon background. A calculation of
two-photon production in hadronic collisions at full next-to-leading order is
described. It includes photons originating from the hadronization of QCD
partons which play an important role at the LHC. A prediction for the invariant
mass distribution for photon pairs at the LHC is presented and finally the
residual scale dependencies are discussed.


title: Small x, Saturation and the High Energy Limit of QCD

abstract:
  The high energy limit of QCD is controlled by the small-$x$ part of a hadron
wavefunction. We argue that this part is universal to all hadrons and is
composed of a new form of matter: a Colored Glass Condensate. This matter is
weakly interacting at very small $x$, but is non-perturbative because of the
highly occupied boson states which compose the condensate. Such a matter might
be studied in high energy lepton-hadron or hadron-hadron interactions.


title:
Next-to-Leading Order SUSY-QCD Predictions for Associated Production of
  Gauginos and Gluinos

abstract:
  We present complete results of a next-to-leading order calculation of the
production of gaugino-like charginos ($\chargino$) and neutralinos
($\neutralino$) in association with gluinos ($\gluino$) at hadron colliders,
including the strong corrections from the exchange of colored particles and
sparticles. Adopting a variety of models for the sparticle mass spectrum,
including typical supergravity (SUGRA) models and a light gluino model, we
provide predictions for total and differential cross sections at the energies
of the Fermilab Tevatron and CERN Large Hadron Collider (LHC).


title: CPT-odd Resonances in Neutrino Oscillations

abstract:
  We consider the consequences for future neutrino factory experiments of small
CPT-odd interactions in neutrino oscillations. The \nu_\mu\to\nu_\mu and
\bar\nu_\mu\to\bar\nu_\mu survival probabilities at a baseline L=732 km can
test for CPT-odd contributions at orders of magnitude better sensitivity than
present limits. Interference between the CPT-violating interaction and CPT-even
mass terms in the Lagrangian can lead to a resonant enhancement of the
oscillation amplitude. For oscillations in matter, a simultaneous enhancement
of both neutrino and antineutrino oscillation amplitudes is possible.


title:
Asymptotic Improvement of Resummation and Perturbative Predictions in
  Quantum Field Theory

abstract:
  The improvement of resummation algorithms for divergent perturbative
expansions in quantum field theory by asymptotic information about perturbative
coefficients is investigated. Various asymptotically optimized resummation
prescriptions are considered. The improvement of perturbative predictions
beyond the reexpansion of rational approximants is discussed.


title:
Predictions for associated production of gauginos and gluinos at NLO in
  SUSY-QCD

abstract:
  NLO SUSY-QCD contributions to associated production of gluinos and gauginos
are shown to enhance the cross sections by about 10% at the Tevatron and by as
much as a factor of two at the LHC. They shift the mass determinations or
discovery limits, soften the $p_T$ spectra, and stabilize the predictions
against variations of the renormalization and factorization scales.


title:
The contribution of the hadronic component of the photon into the
  $D^*$-meson photoproduction at HERA

abstract:
  In the framework of the vector dominance model (VDM) new contribution into
the cross-section of $D^*$-meson photoproduction at HERA has been estimated.
This contribution is due to the interaction of the virtual vector $c\bar
c$-mesons from photon with the proton. It has been shown that the mechanism
under discussion plays the essential role for all values of transverse momentum
of $D^*$-mesons at HERA. Taking into account for the contribution of this
mechanism improves the description of the experimental cross section
distribution.


title: Probing the QCD pomeron in high-energy $\gamma^*\gamma^*$ collisions

abstract:
  Based on the color dipole representation, we investigate consequences for the
$\gamma^{*}\gamma^{*},\gamma^{*}\gamma$ scattering of the finding by Fadin,
Kuraev and Lipatov that incorporation of asymptotic freedom into the BFKL
equation makes the QCD pomeron a series of isolated poles in the angular
momentum plane. We present parameter-free predictions for the vacuum exchange
contribution to the photon structure function which agree well with OPAL and L3
determinations. A good agreement is found between our predictions for the
energy and photon virtuality dependence of the photon-photon cross section
$\sigma^{\gamma^*\gamma^*}(W,Q^2,P^2)$ and the recent data taken by the L3
Collaboration.


title:
Weak hyperon decays in heavy baryon chiral perturbation theory:
  Renormalization and applications

abstract:
  The complete renormalization of the weak Lagrangian to chiral order q^2 in
heavy baryon chiral perturbation theory is performed using heat kernel
techniques. The results are compared with divergences appearing in the
calculation of Feynman graphs for the nonleptonic hyperon decay Lambda -> p
pi^- and an estimate for the size of the counterterm contributions to the
s-wave amplitudes in nonleptonic hyperon decays is given.


title: Relating m_Higgs to m_SUSY by a loop factor

abstract:
  We assume that the scale of the soft supersymmetry breaking masses, m_SUSY,
sliding at tree level, is fixed by the minimization of the potential, but
without a significant contribution of the cosmological term. Under these
assumptions the electroweak breaking scale gets related to m_SUSY by a loop
factor. Applied to specific models of supersymmetry breaking, this mechanism
naturally gives sparticles slightly above all present accelerator bounds.


title: D Branes and Textures

abstract:
  We examine the flavor structure of the trilinear superpotential couplings
which can result from embedding the Standard Model within D brane sectors in
Type IIB orientifold models, which are examples within the Type I string
framework. We find in general that the allowed flavor structures of the Yukawa
coupling matrices to leading order are given by basic variations on the
"democratic" texture ansatz. In certain interesting cases, the Yukawa couplings
have a novel structure in which a single right-handed fermion couples
democratically at leading order to three left-handed fermions. We discuss the
viability of such a ``single right-handed democracy'' in detail; remarkably,
even though there are large mixing angles in the u,d sectors separately, the
CKM mixing angles are small. The analysis demonstrates the ways in which the
Type I superstring framework can provide a rich setting for investigating novel
resolutions to the flavor puzzle.


title:
On the hadron production from the quark-gluon plasma phase in
  ultra-relativistic heavy-ion collisions

abstract:
  We describe the quark gluon plasma (QGP) as a thermalized quark-gluon system,
the thermalized QGP phase of QCD. The hadronization of the thermalized QGP
phase is given in a way resembling a coalescence model with correlated quarks
and anti-quarks. The input parameters of the approach are the spatial volumes
of the hadronization. We introduce three dimensionless parameters C_M, C_B and
C_\bar{B} related to the spatial volumes of the production of low-lying mesons
(M), baryons (B) and antibaryons (\bar{B}). We show that at the temperature T=
175 MeV our predictions for the ratios of multiplicities agree good with the
presently available set of hadron ratios measured for various experiments given
by NA44, NA49, NA50 and WA97 Collaborations on Pb+Pb collisions at 158
GeV/nucleon, NA35 Collaboration on S+S collisions and NA38 Collaboration on O+U
and S+U collisions at 200 GeV/nucleon.


title: Minimal Model for Neutrino Masses and Mixings

abstract:
  Working in the framework of three chiral neutrinos with Majorana masses, we
investigate a scenario first realized in an explicit model by Zee: that the
neutrino mass matrix is strictly off-diagonal in the flavor basis, with all its
diagonal entries precisely zero. This CP-conserving ansatz leads to two
relations among the three mixing angles $(\theta_1, \theta_2, \theta_3)$ and
two squared mass differences. We impose the constraint $|m_3^2 - m_2^2| \gg
|m^2_2 - m_1^2|$ to conform with experiment, which requires the $\theta_i$ to
lie nearby one of four 1-parameter domains in $\theta$-space. We exhibit the
implications for solar and atmospheric neutrino oscillations in each of these
cases. A unique version of the Zee {\it ansatz} survives confrontation with
experimental data, one which necessarily involves maximal just-so vacuum
oscillations of solar neutrinos.


title: Lambda polarization in pp -> p\Lambda K^+ \pi^+\pi^-\pi^+\pi^-

abstract:
  We show that there is a correlation between the invariant mass of the
produced \Lambda K^+, \Lambda K^+\pi^+\pi^- or \Lambda K^+ \pi^+\pi^-\pi^+\pi^-
system in the exclusive reaction pp\to p\Lambda K^+\pi^+\pi^-\pi^+\pi^- and the
longitudinal or transverse momentum of $\Lambda$. Together with the
longitudinal and transverse momentum dependence of Lambda polarization observed
in inclusive reactions, such a correlation implies a dependence of Lambda
polarization on these invariant masses. The qualitative features of this
dependence are consistent with the recent observation by E766 collaboration at
BNL. A quantitative estimation has been made using an event generator for $pp$
collisions. A detailed comparison with the data is made.


title: There is no $\kappa(900)$

abstract:
  In the I=0 sector there are more scalar mesons than can fit in one $q{\bar
q}$ nonet. Consequently, many have claimed that there is in fact more than one
multiplet, perhaps both $q{\bar q}$ and $qq{\bar {qq}}$. Such proposals require
the existence of at least two strange isodoublets (and their antiparticles).
The current PDG Tables list just one state, the $K^*_0(1430)$, while fits to
data with Breit-Wigner forms and variable backgrounds can accommodate a
$\kappa(900)$ too. Whether a state exists in the spectrum of hadrons is not a
matter of ability to fit data along the real energy axis, but is completely
specified by the number of poles in the complex energy plane. Here we perform a
model-independent analytic continuation of $\pi K$ scattering results between
825 MeV and 2 GeV to determine the number and position of resonance poles. We
find that there {\bf is} a $K^*_0(1430)$, but {\bf no} $\kappa(900)$. The LASS
data cannot rule out the possibility of a very low mass $\kappa$ well below 825
MeV.


title: Off-Forward Parton Distributions in 1+1 Dimensional QCD

abstract:
  We use two-dimensional QCD as a toy laboratory to study off-forward parton
distributions (OFPDs) in a covariant field theory. Exact expressions (to
leading order in $1/N_C$) are presented for OFPDs in this model and are
evaluated for some specific numerical examples. Special emphasis is put on
comparing the $x>\zeta$ and $x<\zeta$ regimes as well as on analyzing the
implications for the light-cone description of form factors.


title:
The Quark-Antiquark Asymmetry of the Nucleon Sea from $\Lambda$ and
  $\bar{\Lambda}$ Fragmentation

abstract:
  We present a general analysis of the spin transfer for $\Lambda$ and
$\bar{\Lambda}$ production in deep-inelastic scattering of polarized charged
leptons on the nucleon, and find that the pattern of different behaviors of
$\Lambda$ and $\bar{\Lambda}$ production observed by the E665 Collaboration
suggests the possibility of quark-antiquark asymmetries either in the quark to
$\Lambda$ fragmentation functions and/or in the quark and antiquark
distributions of the target proton. We also point out that the
strange-antistrange asymmetry of the nucleon sea may produce an observable
contribution to the different behaviors of $\Lambda$ and $\bar{\Lambda}$
production. We find that a softer $\bar{s}(x)$ than $s(x)$ as predicted by the
light-cone baryon-meson fluctuation model of intrinsic quark-antiquark pairs of
the nucleon sea might lead to a reasonable picture. However, the magnitude is
still too small to explain the E665 data and the conclusion has also strong
model-dependence. This may suggest the importance of quark-antiquark asymmetry
in the quark to $\Lambda$ fragmentation functions, provided that the E665 data
are confirmed.


title: Bulk U(1) Messenger

abstract:
  We propose a new U(1) gauge interaction in the bulk in higher dimensional
spacetime, which transmits supersymmetry-breaking effects on the hidden brane
to the observable our brane. We find that rather small gauge coupling constant
of U(1)_{bulk}, $\alpha_{bulk} \simeq 5 \times 10^{-4}$, is required for a
successful phenomenology. This result implies the compactification length $L$
of the extra dimension to be $L^{-1} \simeq 2 \times 10^{15}GeV$ for
(4+1)-dimensional spacetime. This large compactification length $L$ is a
crucial ingredient to suppress unwanted flavor-changing neutral currents and
hence our proposal is very consistent with the Randall-Sundrum brane-world
scenario.


title: The effect of many sources on the genuine multiparticle correlations

abstract:
  We report on a study aimed to explore the dependence of the genuine
multiparticle correlations on the number of sources when the influence of other
possible factors during multihadron production are avoided. The analysis
utilised the normalised cumulants calculated in three-dimensional phase space
of the reaction ee -> Z -> hadrons using a large Monte Carlo sample.
  The multi-sources events were simulated by overlaying a few independent
single ee annihilation events.
  It was found that as the number of sources increases, the cumulants do not
change significantly their structure, but those of an order higher than two
decrease fast in their magnitude.
  This reduction and its amount can be understood in terms of combinatorial
considerations of source mixing which dilutes the correlations.
  The diminishing of the genuine correlations is consistent with recent
cumulant measurements in hadron and nucleus induced reactions and should also
be relevant to other dynamical correlations like the Bose-Einstein one, in ee
-> WW -> hadrons and in nucleus-nucleus reactions.