title:
Coherent Exclusive Exponentiation for Precision Monte Carlo Calculations
  of Fermion Pair Production / Precision Predictions for (Un)stable W+W- Pairs

abstract:
  We present the new Coherent Exclusive Exponentiation (CEEX), in comparison to
the older Exclusive Exponentiation (EEX) and the semi-analytical Inclusive
Exponentiation (IEX), for the process e+e- -> f-bar f + n(gamma),
f=mu,tau,d,u,s,c,b, with validity for centre of mass energies from tau lepton
threshold to 1 TeV. We analyse 2f numerical results at the Z-peak, 189 GeV and
500 GeV. We also present precision calculations of the signal processes e+e- ->
4f in which the double resonant W+W- intermediate state occurs using our
YFSWW3-1.14 MC. Sample 4f Monte Carlo data are explicitly illustrated in
comparison to the literature at LEP2 energies. These comparisons show that a TU
for the signal process cross section of 0.4 percent is valid for the LEP2 200
GeV energy. LC energy results are also shown.


title: Effects of anomalous couplings of the tau lepton

abstract:
  The dimension-six CP-conserving $SU_L(2)\times U_Y(1)$ invariant operators
involving the tau lepton are studied. It leads to the new physics effects to
the lepton flavor violation (LFV) and lepton flavor-changing neutral
current(FCNC). With the available experimental data on the decays $Z \to \tau^+
+ \tau^- $, $Z\to \mu^+ + \mu^- $ and $\mu^- \to e^- +\gamma$, the constraints
on parameters of the effective lagrangian can be given. According to such
constraints, the branching ratio of the decay $Z\to \mu^\pm + \tau^\mp $ could
reach to $10^{-6}-10^{-7}$. The size of the LFV effects depends crucially on
the dynamics of the lepton mass generation. Assuming the lepton mass matrices
in the form of a Fritzsch ansatz, we point out that the experiment on $\mu\to e
\gamma$ will put stronger limits on the anomalous magnitic and electric dipole
moments of the tau lepton than obtained by Escribano and Mass\'{o}.


title: Non Abelian Gauge Couplings in Four Fermion Processes at LEP

abstract:
  The LEP data on four fermion processes are presently used to study the non
abelian gauge couplings of the Standard Model. The present theoretical error
for two classes of processes, single-W production and radiative four fermion
final states, is discussed according to the results of the four fermion working
group of the LEP2 Monte Carlo Workshop held at CERN.


title: What if the Higgs Boson Weighs 115 GeV?

abstract:
  If the Higgs boson indeed weighs about 114 to 115 GeV, there must be new
physics beyond the Standard Model at some scale \la 10^6 GeV. The most
plausible new physics is supersymmetry, which predicts a Higgs boson weighing
\la 130 GeV. In the CMSSM with R and CP conservation, the existence, production
and detection of a 114 or 115 GeV Higgs boson is possible if \tan\beta \ga 3.
However, for the radiatively-corrected Higgs mass to be this large, sparticles
should be relatively heavy: m_{1/2} \ga 250 GeV, probably not detectable at the
Tevatron collider and perhaps not at a low-energy e^+ e^- linear collider. In
much of the remaining CMSSM parameter space, neutralino-stau coannihilation is
important for calculating the relic neutralino density, and we explore
implications for the elastic neutralino-nucleon scattering cross section.


title:
Neutrinos from SN1987A, Earth matter effects and the LMA solution of the
  solar neutrino problem

abstract:
  We study properties of the oscillation effects in the matter of the Earth on
antineutrino fluxes from supernovae. We show that these effects can provide
explanation of the difference in the energy spectra of the events detected by
Kamiokande-2 and IMB detectors from SN1987A as well as the absence of
high-energy events with $E\gta 40$ MeV. This explanation requires the neutrino
oscillation parameters $\Delta m^2$ and $\sin^2 2\theta $ to be in the region
of the LMA solution of the solar neutrino problem and the normal mass hierarchy
if $|U_{e 3}|^2\gta 10^{-3}$. The hierarchy can be inverted if $|U_{e 3}|^2\ll
10^{-3}$. The solution of the solar neutrino problem based on
$\nu_e$-conversion to a pure sterile state is disfavoured by SN1987A data.


title: Color Superconductivity in Compact Stars

abstract:
  After a brief review of the phenomena expected in cold dense quark matter,
color superconductivity and color-flavor locking, we sketch some implications
of recent developments in our understanding of cold dense quark matter for the
physics of compact stars. We give a more detailed summary of our recent work on
crystalline color superconductivity and the consequent realization that (some)
pulsar glitches may originate in quark matter.


title: QCD coherence effects in high energy reactions with nuclei

abstract:
  In this work, coherence effects in deep inelastic scattering (DIS) and in the
Drell-Yan (DY) process off nuclei are investigated, in particular nuclear
shadowing. The target rest frame and the color dipole formulation are employed.
Multiple scatterings are treated in Glauber-Gribov theory, which is modified to
include the nuclear form factor to all orders. Based on the mean coherence
length, which is defined in this work, it is estimated that gluon shadowing is
negligible at x_{Bj}>0.01. Parameter free calculations are compared to NMC and
E665 data for DIS and to E772 data for DY. In both cases, good agreement is
found. It is however not possible to reproduce the effect observed by HERMES.
For dileptons in proton-nucleus collisions at RHIC energies, considerable
shadowing for the whole x_F range is predicted. The influence of the nucleus on
the DY transverse momentum distribution is also studied. Furthermore, a new
parametrization of the dipole cross section is presented.


title: Time Evolution of Fast Particles During the Decay of Hadronic Systems

abstract:
  A phenomenological model is presented based on the formation of nuclear
thermodynamic system during the collision of heavy ions in the regime of
intermediate and high energy regions. The formulation and the dynamic picture
are determined by solving the Vlasov equation. The solution is dressed in the
form of a power series. The first term of which is the equilibrium distribution
in phase space. The rest, are time dependent perturbation terms due to the
multiple strong interactions inside the system. The temperature gradient and
the derivatives of the phase function are calculated. The time dependence of
the angular emission of the produced particles is studied. It is found that
particles emitted in the forward direction are produced in the early stage of
the reaction, far from the equilibrium. Backward production comes in a later
stage when the system constituents undergo multiple cascade collisions.


title:
High-order corrections and subleading logarithms for top quark
  production

abstract:
  We derive high-order threshold corrections for top quark production in
hadronic collisions from resummation calculations. We present analytical
expressions for the cross section through
next-to-next-to-next-to-next-to-leading order (N^4LO) and
next-to-next-to-leading logarithmic accuracy. Special attention is paid to the
role of subleading logarithms and how they relate to the convergence of the
perturbation series and differences between various resummation prescriptions.
It is shown that care must be taken to avoid unphysical terms in the
expansions. Numerical results are presented for top quark production at the
Tevatron. We find sizeable increases to the total cross section and
differential distributions and a dramatic reduction of the factorization scale
dependence relative to next-to-leading order.


title: b -> s \gamma and supersymmetry with large tan\beta

abstract:
  We discuss the constraints on the supersymmetric parameter space from the
decay mode b -> s \gamma for large values of tan\beta. We improve the
theoretical prediction for the decay rate by summing very large radiative
corrections to all orders in perturbation theory. This extends the validity of
the perturbative calculation to the large tan\beta regime. This resummation of
terms of order alpha_s^n tan^{n+1}\beta uses a recently proposed effective
lagrangian for the Yukawa interaction of bottom quarks. Moreover, we identify
an additional source of tan\beta-enhanced terms, which are of order alpha_s
tan\beta and involve the charged Higgs boson, and analyze their behaviour in
higher orders of perturbation theory. After correcting the current expressions
for this rare decay branching ratio at next-to-leading order, we obtain that,
contrary to recent claims, the presently measured branching ratio of b -> s
\gamma constrains the supersymmetric parameter space in a relevant way, even if
tan\beta is large.


title:
New Formulas and Predictions for Running Fermion Masses at Higher Scales
  in SM, 2HDM, and MSSM

abstract:
  Including contributions of scale-dependent vacuum expectation values, we
derive new analytic formulas and obtain substantially different numerical
predictions for the running masses of quarks and charged-leptons at higher
scales in the SM, 2HDM and MSSM. These formulas exhibit significantly different
behaviours with respect to their dependence on gauge and Yukawa couplings than
those derived earlier. At one-loop level the masses of the first two
generations are found to be independent of Yukawa couplings of the third
generation in all the three effective theories in the small mixing limit.
Analytic formulas are also obtained for running $\tan\beta(\mu)$ in 2HDM and
MSSM. Other numerical analyses include study of the third generation masses at
high scales as functions of low-energy values of $\tan\beta$ and SUSY scale
$M_S=M_Z-10^4$ GeV.


title: Tau lepton Michel parameters and new physics

abstract:
  A complete discussion of the constraints on the Michel parameters and the
ambiguities of their interpretation is presented. Estimators of new physics,
optimized for a very wide class of hypotheses and models, are proposed.


title: The heavy neutral Higgs signature in the gamma gamma to Z Z process

abstract:
  If the Standard Model (SM) Higgs particle is sufficiently heavy, then its
contribution to gamma gamma to Z Z should be largely imaginary, interfering
with the also predominantly imaginary SM "background" generated by the W-loop.
For standard model Higgs masses in the region 200 \lsim m_H \lsim 500 GeV, this
interference is found to be constructive and increasing the Higgs signal. In
the minimal SUSY case an interference effect should also appear for the
contribution of the heavier CP-even neutral Higgs boson H^0, provided it is
sufficiently heavy. The effect is somewhat reduced though, by the smallness of
the H^0 width and the gamma gamma and ZZ branching ratios. The interference is
again found to be constructive for part of the parameter space corresponding to
sfermion masses at the TeV scale and maximal stop mixing. For both the SM and
SUSY cases, regions of the parameter space exist though, where the interference
may be destructive. It is therefore essential to take these effects into
account when searching for possible scalar Higgs-like candidates. To this aim,
we present the complete analytic expressions for both resonance and background
amplitudes.


title: Weak Decays of Heavy Quarks

abstract:
  We review some aspects of weak decays of hadrons containing one heavy quark.
The main emphasis is on $B$ physics, in particular in the framework of the
Heavy Quark Effective Theory.


title: Chiral Limit Prediction for epsilon'/epsilon at NLO in 1/N_c

abstract:
  We report on a calculation of $\epsilon_K'/\epsilon_K$ at next-to-leading in
the $1/N_c$ expansion and to lowest order in Chiral Perturbation Theory. We
discuss the short-distance matching, the scale and scheme dependence as well as
the long-distance short-distance matching. We include the two known chiral
corrections to our result and discuss further order $p^4$ corrections to it.


title:
Large nu_mu->nu_tau and nu_e->nu_tau transitions in short-baseline
  experiments?

abstract:
  Considering four-neutrino schemes of type 3+1, we identify four small regions
of the neutrino mixing parameter space compatible with all data. Assuming a
small mixing between the sterile neutrino and the isolated mass eigenstate we
show that large nu_mu->nu_tau and nu_e->nu_tau transitions are predicted in
short-baseline experiments and could be observed in the near future in
dedicated experiments. We discuss also implications for solar, atmospheric and
long-baseline neutrino experiments and we present a formalism that allows to
describe in 3+1 schemes atmospheric neutrino oscillations, long-baseline nu_mu
disappearance and nu_mu->nu_tau transitions in matter.


title: Extra Dimensions: A View from the Top

abstract:
  In models with compact extra dimensions, where the Standard Model fields are
confined to a 3+1 dimensional hyperplane, the $t \bar t$ production
cross-section at a hadron collider can receive significant contributions from
multiple exchange of KK modes of the graviton. These are carefully computed in
the well-known ADD and RS scenarios, taking the energy dependence of the sum
over graviton propagators into account. Using data from Run-I of the Tevatron,
95% C.L. bounds on the parameter space of both models are derived. For Run-II
of the Tevatron and LHC, discovery limits are estimated.


title: Final State Interactions and eps'/eps

abstract:
  I discuss the role of strong final state interactions (FSI) in K \to 2\pi
decays. In this case strong FSI effects can be resummed [1,2] by solving the
Omn\`es problem for K\to 2\pi amplitudes. Implications for the CP conserving
Delta I=1/2 ratio and the direct CP violation parameter eps'/eps are also
discussed.


title: QCD Radiation off Heavy Particles

abstract:
  We study QCD radiation in decay processes involving heavy particles. As
input, the first-order gluon emission rate is calculated in a number of
reactions, and comparisons of the energy flow patterns show a non-negligible
process dependence. To proceed further, the QCD parton shower language offers a
convenient approach to include multi-gluon emission effects, and to describe
exclusive event properties. An existing shower algorithm is extended to take
into account the process-dependent mass, spin and parity effects, as given by
the matrix element calculations. This allows an improved description of
multiple gluon emission effects off b and t quarks, and also off nonstandard
particles like squarks and gluinos. Phenomenological applications are presented
for bottom production at LEP, Higgs particle decay to heavy flavours, top
production and decay at linear colliders, and some simple supersymmetric
processes.


title: The charmed and bottom meson spectrum from lattice NRQCD

abstract:
  The mass spectrum of S and P-wave mesons containing a single heavy quark has
been computed using quenched lattice nonrelativistic QCD. Numerical results
have been obtained at first, second and third order in the heavy quark
expansion, so convergence can be discussed. The computed spectrum of charmed
and bottom mesons is compared to existing model calculations and experimental
data.


title: Bounds in proton-proton elastic scattering at low momentum transfer

abstract:
  We present a bound on the imaginary part of the single helicity-flip
amplitude for spin 1/2-spin 1/2 scattering at small momentum transfer. The
variational method of Lagrange multipliers is employed to optimize the
single-flip amplitude using the values of the total cross section, the elastic
cross section and diffraction slope as equality constraints in addition to the
inequality constraints resulting from unitarity. Such bounds provide important
information related to the determination of polarization of a proton beam. In
the case of elastic proton collisions the analyzing power at small scattering
angles inside the Coulomb Nuclear Interference region offers a method of
measuring the polarization of a proton beam, the accuracy of the polarization
measurement depending on the single helicity-flip amplitude. The bound obtained
on the imaginary part of the single helicity-flip amplitude indicates that the
analyzing power for proton-proton collisions in the Coulomb nuclear
interference region should take positive nonzero values at high energies.


title: QCD analysis of the diffractive structure function F_2^{D(3)}

abstract:
  The proton diffractive structure function $F_2^{D(3)}$ measured in the H1 and
ZEUS experiments at HERA is analyzed in terms of both Regge phenomenology and
perturbative QCD evolution. A new method determines the values of the Regge
intercepts in ``hard'' diffraction, confirming a higher value of the Pomeron
intercept than for soft physics. The data are well described by a QCD analysis
in which point-like parton distributions, evolving according to the DGLAP
equations, are assigned to the leading and sub-leading Regge exchanges. The
gluon distributions are found to be quite different for H1 and ZEUS. A {\it
global fit} analysis, where a higher twist component is taken from models,
allows us to use data in the whole available range in diffractive mass and
gives a stable answer for the leading twist contribution. We give sets of quark
and gluon parton distributions for the Pomeron, and predictions for the charm
and the longitudinal proton diffractive structure function from the QCD fit. An
extrapolation to the Tevatron range is compared with CDF data on single
diffraction. Conclusions on factorization breaking depend critically whether H1
(strong violation) or ZEUS (compatibility at low $\beta$) fits are taken into
account.


title:
Nuclear shadowing in polarized DIS on ^6LiD at small x and its effect on
  the extraction of the deuteron spin structure function g_{1}^{d}(x,Q^2)

abstract:
  We consider the effect of nuclear shadowing in polarized deep inelastic
scattering (DIS) on ^6LiD at small Bjorken x and its relevance to the
extraction of the deuteron spin structure function g_{1}^{d}(x,Q^2). Using
models, which describe nuclear shadowing in unpolarized DIS, we demonstrate
that the nuclear shadowing correction to g_{1}^{d}(x,Q^2) is significant.


title: High-Energy-Physics Event Generation with PYTHIA 6.1

abstract:
  PYTHIA version 6 represents a merger of the PYTHIA 5, JETSET 7 and SPYTHIA
programs, with many improvements. It can be used to generate
high-energy-physics `events', i.e. sets of outgoing particles produced in the
interactions between two incoming particles. The objective is to provide as
accurate as possible a representation of event properties in a wide range of
reactions. The underlying physics is not understood well enough to give an
exact description; the programs therefore contain a combination of analytical
results and various models. The emphasis in this article is on new aspects, but
a few words of general introduction are included. Further documentation is
available on the web.


title:
Production of Charginos, Neutralinos, and Third Generation Sfermions at
  an e+e- Linear Collider

abstract:
  We discuss the production of charginos, neutralinos, and third generation
sfermions in $e^+e^-$ annihilation in the energy range $\sqrt{s} = 0.2-1$ TeV.
We present numerical predictions within the Minimal Supersymmetric Standard
Model for the cross sections and study the importance of beam polarization for
the determination of the underlying SUSY parameters.


title: q-Boson approach to multiparticle correlations

abstract:
  An approach is proposed enabling to effectively describe, for relativistic
heavy-ion collisions, the observed deviation from unity of the intercept
\lambda (measured value corresponding to zero relative momentum {\bf p} of two
registered identical pions or kaons) of the two-particle correlation function
C(p,K). The approach uses q-deformed oscillators and the related picture of
ideal gas of q-bosons. In effect, the intercept \lambda is connected with
deformation parameter q. For a fixed value of q, the model predicts specific
dependence of \lambda on pair mean momentum {\bf K} so that, when |{\bf
K}|\gsim 500 - 600 MeV/c for pions or when |{\bf K}|\gsim 700 - 800 MeV/c for
kaons, the intercept \lambda tends to a constant which is less than unity and
determined by q. If q is fixed to be the same for pions and kaons, the
intercepts \lambda_\pi and \lambda_K essentially differ at small mean momenta
{\bf K}, but tend to be equal at {\bf K} large enough (|{\bf K}|\gsim 800MeV/c)
where the effect of resonance decays can be neglected. We argue that it is of
basic interest to check in the experiments on heavy ion collisions: (i) the
exact shape of dependence \lambda = \lambda({\bf K}), and (ii) whether for
|{\bf K}| \gsim 800 MeV/c the resulting \lambda_\pi and \lambda_K indeed
coincide.

categories: hep-ph cond-mat hep-ex hep-th nucl-ex nucl-th quant-ph


title: Long-range particle correlations and wavelets

abstract:
  The problem of long-range correlations of particles produced in high- energy
collisions is discussed. Long-range correlations involve large groups of
particles. Among them are, e.g., those correlations which lead to ring-like and
elliptic flow shapes of individual high-multiplicity events in the
polar+azimuthal angles plane. The \w method of \an which allows to disentangle
various patterns has been proposed and applied to some central lead-lead
collisions at energy 158 GeV per nucleon. Previous attempts to find out the
ring-like correlations and recent results on \w \an of high- energy nuclei
interactions are reviewed.


title: Dynamical (Super)Symmetry Breaking

abstract:
  Dynamical Symmetry Breaking (DSB) is a concept theorists rely on very often
in the discussions of strong dynamics, model building, and hierarchy problems.
In this talk, I will discuss why this is such a permeating concept among
theorists and how they are used in understanding physics. I also briefly review
recent progress in using dynamical symmetry breaking to construct models of
supersymmetry breaking and fermion masses.


title: Cosmology and Hierarchy in Stabilized Randall-Sundrum Models

abstract:
  We consider the cosmology and hierarchy of scales in models with branes
immersed in a five-dimensional curved spacetime subject to radion
stabilization. The universe naturally find itself in the radiation-dominated
epoch when the inter-brane spacing is static and stable, independent of the
form of the stabilizing potential. We recover the standard Friedmann equations
without assuming a specific form for the bulk energy-momentum tensor. We
address the hierarchy problem in the context of a quartic and exponential
stabilizing potential, and find that in either case the presence of a negative
tension brane is required and that the string scale can be as low as the
electroweak scale. In the situation of self-tuning branes (corresponding to an
exponential potential) where the bulk cosmological constant is set to zero, the
brane tensions have hierarchical values.


title: Searching for T-Violating, P-Conserving New Physics with Neutrons

abstract:
  The observance of parity conserving time reversal violation in light quark
systems could signal the presence of physics beyond the Standard Model. I
discuss the implications of low-energy time reversal tests for the existence of
such T-violating, P-conserving (TVPC) interactions. I argue that searches for
permanent electric dipole moments (EDM's) and direct TVPC searches provide
complementary information on P-conserving T-violation. EDM searches yield
constraints only under the assumption that parity symmetry is restored at the
scale Lambda associated with new TVPC physics. If parity remains broken at
short distances, direct searches yield the least ambiguous bounds. In the
latter case, improving the experimental precision of direct TVPC searches in
neutron beta-decay and polarized epithermal neutron transmission at the
Spallation Neutron Source could yield tighter bounds.


title: Current Topics in B Physics

abstract:
  I discuss topics of particular interest in connection with the ongoing
experiments at the B factories BaBar and Belle: B-mixing, QCD effects in
nonleptonic decays and rare decays.


title: Techniques for the Top Squark Search at the Fermilab Tevatron

abstract:
  This dissertation addresses the question of how to detect light top squarks
at the upgraded Fermilab Tevatron collider. After a brief introduction to
supersymmetry, the basic phenomenology of the light stop is reviewed and the
current experimental situation is surveyed. The analysis presented here is
based on collider event simulations. The main decay modes accessible to the
Tevatron are studied, feasible discovery channels are identified, and recipes
for experimental analysis are proposed. It is found that stops with masses up
to the top quark mass are liable to detection under these schemes with the data
from a few years' running at the upgraded Tevatron. With such an extended run,
significant portions of parameter space may be probed.


title:
Can the SO(10) Model with Two Higgs Doublets Reproduce the Observed
  Fermion Masses?

abstract:
  It is usually considered that the SO(10) model with one 10 and one 126 Higgs
scalars cannot reproduce the observed quark and charged lepton masses. Against
this conventional conjecture, we find solutions of the parameters which can
give the observed fermion mass spectra. The SO(10) model with one 10 and one
120 Higgs scalars is also discussed.


title:
On convergence of the ChPT HFF expansion for one loop contribution to
  meson production in NN collisions

abstract:
  We consider the application of heavy fermion formalism based chiral
perturbation theory to meson production in nucleon-nucleon collisions. It is
shown that for one loop contributions the heavy fermion formalism expansion
corrections for the nucleon propagator produce infinite series of correction
terms which are of the same momentum power order. This destroys the one-to-one
correspondence between the perturbative and small momentum expansion and thus
negates the application of any finite order heavy fermion formalism chiral
perturbation theory to the $NN\to NN \pi$ reactions.


title: Equation of State in Quantum Chromodynamics

abstract:
  The equation of state for quark-gluon plasma is obtained, being valid for
arbitrary values of the coupling parameter and of temperature. This equation is
constructed from perturbative expansions for free energy and for
renormalization function. Summation of asymptotic perturbative series is
accomplished by means of the self-similar approximation theory.


title:
Theoretical description of the total gamma*gamma* cross-section and its
  confrontation with the LEP data on doubly tagged e+e- events

abstract:
  We perform a detailed analysis of the total inelastic cross-section for
gamma*gamma* collisions. Different contributions coming from the quark box
diagram, reggeons, the soft and hard pomeron are included. The QCD pomeron
contribution contains a dominant part of subleading effects which reduces its
intercept and delays the onset of the asymptotic pomeron to high energies.
Estimates of the cross-section for doubly-tagged (e+e- to e+e- hadrons) events
are presented and compared with the existing LEP data. Good agreement between
the theoretical results and the experimental data is found. We also comment on
the extraction of the BFKL pomeron intercept from the available LEP
measurements.


title: Low-x scaling in $\gamma^*p$ total cross sections

abstract:
  We show that the experimental data for the total virtual-photon proton cross
section, \sigma_{\gamma^*p} (W^2, Q^2), for x_{bj} \lsim 0.1 lie on a universal
curve, when plotted against \eta = (Q^2 + m^2_0)/ \Lambda^2(W^2), where
\Lambda^2 (W^2) = C_1 (W^2+W^2_0)^{C_2} is determined by the parameters m^2_0,
C_1, C_2 and W^2_0. The observed scaling law follows from the
generalized-vector-dominance/color-dipole picture of low-x deep inelastic
scattering.


title: Progress towards 2 to 2 scattering at two-loops

abstract:
  We discuss the two-loop integrals necessary for evaluating massless 2 to 2
scattering amplitudes. As a test process, we consider the leading colour
two-loop contribution to qqbar to q'qbar'. We show that for physical scattering
processes the two Smirnov-Veretin planar box graphs I1 and I2 are accompanied
by factors of 1/(D-4) thereby necessitating a knowledge of both I1 and I2 to
O(epsilon). Using an alternative basis I1 and the irreducible numerator
integral I3, the factors of 1/(D-4) disappear.


title: QCD Potentiology

abstract:
  We review the connection between QCD and potential models of quarkonia in the
framework of effective field theories, with an emphasis on non-perturbative
methods such as lattice simulations. The static and heavy quark potentials are
introduced and the applicability of the non-relativistic and adiabatic
approximations are discussed. The roles of so-called hybrid potentials are
explored and we comment on the QCD analogue of the QED Lamb shift.


title: Effective Interactions are Effective Interactions

abstract:
  The subject of effective interactions is introduced and applications in both
quantum mechanics and quantum field theory are presented. In particular the use
of chiral perturbation theory as an effective low energy description of QCD is
developed and it is argued that such methods rally are effective in both the
meson and baryonic sectors.


title: Chiral phase transition in a covariant nonlocal NJL model

abstract:
  The properties of the chiral phase transition at finite temperature and
chemical potential are investigated within a nonlocal covariant extension of
the Nambu-Jona-Lasinio model based on a separable quark-quark interaction. We
consider both the situation in which the Minkowski quark propagator has poles
at real energies and the case where only complex poles appear. In the
literature, the latter has been proposed as a realization of confinement. In
both cases, the behaviour of the physical quantities as functions of T and \mu
is found to be quite similar. In particular, for low values of T the chiral
transition is always of first order and, for finite quark masses, at certain
"end point" the transition turns into a smooth crossover. In the chiral limit,
this "end point" becomes a "tricritical" point. Our predictions for the
position of these points are similar, although somewhat smaller, than previous
estimates. Finally, the relation between the deconfining transition and chiral
restoration is also discussed.


title: The Utility of Quantum Field Theory

abstract:
  This talk surveys a broad range of applications of quantum field theory, as
well as some recent developments. The stress is on the notion of effective
field theories. Topics include implications of neutrino mass and a possible
small value of $\sin(2\beta)$, supersymmetric extensions of the standard model,
the use of field theory to understand fundamental issues in string theory (the
problem of multiple ground states and the question: does string theory predict
low energy supersymmetry), and the use of string theory to solve problems in
field theory. Also considered are a new type of field theory, and indications
from black hole physics and the cosmological constant problem that effective
field theories may not completely describe theories of gravity.


title: Spin-Dependent WIMPs in DAMA?

abstract:
  We investigate whether the annual modulation observed in the DAMA experiment
can be due to a weakly-interacting massive particle (WIMP) with an axial-vector
(spin-dependent; SD) coupling to nuclei. We evaluate the SD WIMP-proton cross
section under the assumption that such scattering accounts for the DAMA
modulation, and we do the same for a SD WIMP-neutron cross section. We show
that SD WIMP-proton scattering is ruled out in a model-independent fashion by
null searches for energetic neutrinos from WIMP annihilation in the Sun, and
that SD WIMP-neutron scattering is ruled out for WIMP masses > 20 GeV by the
null result with the DAMA Xe detector. A SD WIMP with mass < 20 GeV is still
compatible, but only if the SD WIMP-neutron interaction is four orders of
magnitude greater than the WIMP-proton interaction.


title: Neutron EDM from Electric and Chromoelectric Dipole Moments of Quarks

abstract:
  Using QCD sum rules, we calculate the electric dipole moment of the neutron
d_n induced by all CP violating operators up to dimension five. We find that
the chromoelectric dipole moments of quarks \tilde d_i, including that of the
strange quark, provide significant contributions comparable in magnitude to
those induced by the quark electric dipole moments d_i. When the theta term is
removed via the Peccei-Quinn symmetry, the strange quark contribution is also
suppressed and d_n =(1\pm 0.5)[1.1e(\tilde d_d + 0.5\tilde
d_u)+1.4(d_d-0.25d_u)].


title: Three-Neutrino Analysis of the Super-Kamiokande Solar Neutrino Data

abstract: Withdrawn by the authors due to crucial errors in equations (1) and (2).


title: Chiral Symmetry Restoration and the sigma-meson

abstract:
  The sigma-meson, which is at best a broad resonance in the vacuum, may suffer
a substantial red-shift and appear as a soft and narrow collective mode at
finite temperature and baryon densities. The physics behind this softening
phenomena and its relation to the partial restoration of chiral symmetry are
discussed. Possible experiments in laboratory to test the idea are also
summarized.


title: Two-photon annihilation into pion pairs

abstract:
  We discuss pion pair production in two-photon collisions in two different
kinematical regimes. When both photons are real and at moderately large
center-of-mass energy s we elaborate on partonic transverse momentum and
Sudakov corrections within the hard scattering approach. We also point out the
difference between our approach and that of other authors. When one of the
photons is highly virtual the produced pion pair can be described in terms of a
two-pion distribution amplitude, for which we derive the perturbative limit at
large s.


title: Comments on parton saturation at small x in large nuclei

abstract:
  It is argued that the gluon density introduced by A.Mueller in relation to
the saturation phenomenon is different from the standardly defined one, which
turned out to have a soliton-like form in the numerical calculations. It is
shown that A.Mueller's densities obtained from the latter possess the same
saturation properties as originally predicted.


title:
Theoretical estimate(s) of the CP-violating quontity
  epsilon-prime/epsilon in K -> 2 pi decays

abstract:
  I give a short presentation of the theoretical prediction of
epsilon-prime/epsilon. Short distance and especially long distance aspects of
the computation is discussed. I consentrate on the general framework and the
chiral quark model approach, while other approaches are also shortly presented.
Because of the intrinsic uncertainties of the long-distance computations, it is
unlikely that new physics effects can be disentangled from the standard model
prediction.


title: Lattice regularization for chiral perturbation theory

abstract:
  The SU(3) chiral lagrangian for the lightest octets of mesons and baryons is
constructed on a spacetime lattice. The lattice spacing acts as an ultraviolet
momentum cutoff which appears directly in the Lagrangian so chiral symmetry
remains explicit. As the lattice spacing vanishes, Feynman loop diagrams
typically become divergent due to inverse powers of the lattice spacing, and
these divergences get absorbed into counterterms such that the standard results
of dimensional regularization are obtained. One advantage of lattice
regularization is that power divergences are seen explicitly. In the present
work, the octet meson masses, the octet baryon masses and the pion-nucleon
sigma term are all computed explicitly to one loop order.


title: Higher-order QCD corrections to $\gamma^*\gamma^*\to hadrons$

abstract:
  I illustrate the techniques and the results of the computation of order-$\as$
corrections to the production of hadrons in the collision of two virtual
photons, that originate from the incoming leptons at $\epem$ colliders.


title:
Pade-Improved Estimate of Perturbative Contributions to Inclusive
  Semileptonic $b\to u$ Decays

abstract:
  Pade-approximant methods are used to estimate the three-loop perturbative
contributions to the inclusive semileptonic $b \to u$ decay rate. These
improved estimates of the decay rate reduce the theoretical uncertainty in the
extraction of the CKM matrix element $|V_{ub}|$ from the measured inclusive
semileptonic branching ratio.


title: A CP-Violating Kinematic Structure

abstract:
  A CP violating kinematic structure is presented. The essential physical input
is to question the textbook wisdom, ``Now when a particle is at rest, one
cannot define its spin as either left- or right-handed, so phi_R(0) =
phi_L(0),'' as found, e.g., in Lewis Ryder's Quantum Field Theory, and in many
other books on the representations of the Lorentz group. It is suggested that
this equality is true only up to a phase. The demand of C, P, and T
covariances, separately, fixes this phase to be pm 1. If these conditions are
relaxed, a natural CP-violating kinematic structure emerges. Having established
a CP-violating kinematic structure, we then discuss how Planck scale physics
necessarily invokes non-commutative space-time and that such changes in the
structure of space-time will force upon us additional violations/deformations
of the CPT structure of space-time, and a violation of the principle of
equivalence via a violation of the Lorentz symmetries. The latter may carry
significant consequences for understanding the data on ultra high energy cosmic
rays.


title:
U_A(1) symmetry breaking, scalar mesons and the nucleon spin problem in
  an effective chiral field theory

abstract:
  We establish a relationship between the scalar meson spectrum and the $U_A
(1)$ symmetry-breaking 't Hooft interaction on one hand and the constituent
quark's flavor-singlet axial coupling constant $g_{A, Q}^{(0)}$ on the other,
using an effective chiral quark field theory. This analysis leads to the new
sum rule $g_{A, Q}^{(0)}[m_{\eta '}^{2} + m_{\eta}^{2} - 2 m_{K}^{2} ]\simeq -
m_{f_{0}^{'}}^{2} - m_{f_{0}}^{2} + 2 m_{K_{0}^{*}}^{2}$, where $\eta^{'},
\eta, K$ are the observed pseudoscalar mesons, $K_{0}^{*}$ is the strange
scalar meson at 1430 MeV and $f_{0}, f_{0}^{'}$ are "the eighth and the ninth"
scalar mesons. We discuss the relationship between the constituent quark
flavor-singlet axial coupling constant $g_{A, Q}^{(0)}$ and the nucleon one
$g_{A, N}^{(0)}$ (``nucleon's spin content'') in this effective field theory.
We also relate $g_{A, Q}^{(0)}$, as well as the flavour-octet constituent quark
axial coupling constant $g_{A, Q}^{(1)}$ to vector and axial-vector meson
masses in general as well as in the tight-binding limit.


title: Heavy ion physics : theory

abstract:
  Lattice quantum chromodynamics (QCD) predicts a new state of matter, called
quark-gluon plasma (QGP), at sufficiently high temperatures or equivalently
large energy densities. Relativistic heavy ion collisions are expected to
produce such energy densities, thereby providing us a chance to test the above
prediction. After a brief introduction of the necessary theoretical concepts, I
present some critical comments on the experimental results with an aim to
examine whether QGP has already been observed experimentally.


title: Aspects of Chiral Symmetry

abstract:
  We give a pedagogical review of implications of chiral symmetry in QCD.
First, we briefly discuss classical textbook subjects such as the axial
anomaly, spontaneous breaking of the flavor-nonsinglet chiral symmetry,
formation of light pseudo-Goldstone particles, and their effective
interactions. Then we proceed to other issues. We explain in some detail a
recent discovery how to circumvent the Nielsen--Ninomiya's theorem and
implement chirally symmetric fermions on the lattice. We touch upon such
classical issues as the Vafa-Witten's theorem and 't Hooft's anomaly matching
conditions. We derive a set of exact theorems concerning the dynamics of the
theory in a finite Euclidean volume and the behavior of the Dirac spectral
density. Finally, we discuss an imaginary world with a nonzero value of the
vacuum angle theta.


title: Applications of non-perturbative renormalization

abstract:
  A short survey of the renormalization problem in QCD and its non-perturbative
solution by means of numerical simulations on the lattice is given. Most
emphasis is on scale dependent renormalizations, which can be reliably
addressed via a recursive finite-size scaling procedure employing a suitable
intermediate renormalization scheme. To illustrate these concepts we discuss
some - partly recent - computations of phenomenologically relevant quantities:
the running QCD gauge coupling, renormalization group invariant quark masses
and the renormalization of the static-light axial current.


title: Laboratory Limits on Theories with Sterile Neutrinos in the Bulk

abstract:
  We discuss the phenomenological consequences of theories which describe
sterile neutrinos in large extra dimensions, in the so-called bulk. We briefly
outline how the cumulative non-decoupling effect due to the tower of
Kaluza-Klein singlet neutrinos may equivalently be described by a
higher-dimensional effective theory with original order-unity Yukawa couplings.
Based on this cumulative phenomenon, we obtain strong constraints on the
fundamental quantum gravity scale and/or on the higher-dimensional Yukawa
couplings.


title: Perturbative QCD analysis of near-to-planar three jet events

abstract:
  We present the all-order resummed thrust minor distribution as a measure of
aplanarity in three-jet events.


title:
Probing the Infrared Structure of Gauge Theories: A Pade-Approximant
  Approach

abstract:
  Pade-approximant treatments of the known terms of the QCD $\beta$-function
are seen to develop possible infrared fixed point structure only if the number
of fermion flavours is sufficiently large. This flavour threshold is seen to be
between six and nine flavours, depending upon both the specific choice of
approximant as well as on the presently-unknown five-loop $\beta$-function
contribution. Below this flavour threshold, Pade approximants based upon the
QCD $\beta$-function manifest the same infrared attractor structure as that
which characterizes the exact NSVZ $\beta$-function of supersymmetric
gluodynamics. Such infrared attractor structure is also seen to characterize
Pade-approximant treatments of vector SU(N) gauge theory in the large $N$
limit, suggesting common infrared dynamics for the strong and weak phases of
this theory.


title: Propagation et oscillations en theorie des champs

abstract:
  After a review of the problems associated with the conventional treatment of
particle oscillations, an oscillation formula is derived within the framework
of quantum field theory. The oscillating particle is represented by its
propagator and the initial and final states by wave packets. It is obviously
relativistic from the start and moreover applies both to stable (neutrinos) and
unstable particles (K and B mesons, unstable neutrinos). CPLEAR and DAFNE
experiments are studied as examples, with special attention directed to CP
violation. The problems resulting from equal energies/momentum/velocities
prescriptions are analyzed and solved. Oscillations of associated particles are
found to be nonexistent. The relativistic generalization of the
Wigner-Weisskopf equation is also derived.


title: Partonic structure of $\gamma_L^*$ in hard collisions

abstract:
  Manifestation of QCD improved partonic structure of longitudinally polarized
virtual photons in hard collisions is discussed. As an example, dijet
production in ep collisions at HERA is investigated in detail.


title:
Hoelder Inequalities and QCD Sum-Rule Bounds on the Masses of Light
  Quarks

abstract:
  QCD Laplace Sum-Rules must satisfy a fundamental Hoelder inequality if they
are to consistently represent an integrated hadronic spectral function. The
Laplace sum-rules of pion currents is shown to violate this inequality unless
the $u$ and $d$ quark masses are sufficiently large, placing a lower bound on
$m_u+m_d$, the SU(2)-invariant combination of the light-quark masses.


title: On the Significance of the Quantity "A Squared"

abstract:
  We consider the gauge potential A and argue that the minimum value of the
volume integral of A squared (in Euclidean space) may have physical meaning,
particularly in connection with the existence of topological structures. A
lattice simulation comparing compact and non-compact ``photodynamics'' shows a
jump in this quantity at the phase transition, supporting this idea.


title: Flavour-dependent SUSY phases and CP asymmetry in B -> X_s gamma decays

abstract:
  We study the direct CP asymmetry in B -> X_s gamma decay in SUSY models with
non-universal A-terms. We show that the flavour-dependent phases of the
A-terms, unlike the flavour-independent ones, can give rise too large
contribution to the CP asymmetry while respecting the experimental bounds on
the branching ratio of B -> X_s gamma decay and the electric dipole moments of
the electron and neutron. The CP asymmetry of this decay is predicted to be
much larger than the standard model prediction in a wide region of the
parameter space. In particular, it can be of order 10-15% which can be
accessible at B factories.


title: The Hard and Soft Contributions in Diffraction: A Closer Look

abstract:
  Disentangle the hard and soft dynamics in diffractive DIS is one of the main
open questions of the strong interactions. We propose the study of the
logarithmic slope in $Q^2$ of the diffractive structure function as a potential
observable to discriminate between the Regge and the QCD-based approaches. Our
results indicate that a future experimental analyzes could evidentiate the
leading dynamics at $ep$ diffractive processes in the HERA kinematical regime.


title: Searching Saturation in eA Processes

abstract:
  The high density effects should be manifest at small x and/or large nuclei.
In this letter we consider the behavior of nuclear structure function $F_2^A$
slope in the kinematic region which could be explored in the future eA
colliders as a search of these effects. We verify that the high density implies
that the maximum value of the slope occurs at large values of the photon
virtuality, i.e. in a perturbative regime, and is dependent of the number of
nucleons A and energy. Our conclusion is that the measurement of this
observable will allow to explicit the saturation.


title:
Application of Discrete Light-Cone Quantization to Yukawa Theory in Four
  Dimensions

abstract:
  The numerical technique of discrete light-cone quantization (DLCQ) is applied
to a single-fermion truncation of Yukawa theory in four dimensions. The
truncated theory is regulated by three Pauli-Villars bosons, which are
introduced directly in the DLCQ Fock-state basis. A special form of the Lanczos
diagonalization algorithm is used to handle the indefinite metric.
Renormalization is done nonperturbatively.


title: The Coulomb Phase Revisited

abstract:
  Motivated by the forthcoming data from the E950 experiment at BNL for small
angle polarized proton-carbon scattering we revisit the problem of Coulomb
phase. The approximation usually used with the momentum transfer squared (q^2)
small compared to the inverse elastic slope is not justified within the
kinematics of the E950 experiment. We go beyond this approximation and derive a
new rather simple expression which recovers the formula of Bethe at small q^2,
but is valid at any momentum transfer.


title:
Perturbative contribution to the sin(phi) asymmetry in inclusive pi^{+}
  electroproduction

abstract:
  We consider the sin(phi) single target-spin asymmetry in deep-inelastic
pi^{+} inclusive electroproduction off a longitudinally polarized target. We
show that at larger transverse momentum of the outgoing hadron the evaluated
asymmetry decreases if one takes into account the first order alpha_S
perturbative contribution to the cross section, integrated over the azimuthal
angle. This leads to good agreement with recent HERMES data.


title: Hadronic Equipartition of Quark and Glue Momenta

abstract:
  If the ``glue'' which binds quarks within hadrons takes the form of strings,
then a virial theorem may be derived which shows how the total hadron four
momentum splits up into a quark contribution plus a glue contribution. The
hadrons made up of light quarks exhibit an equipartion of four momentum into
equal parts quarks and glue. The agreement with the experimental ``parton''
distribution four momentum sum rule is quite satisfactory as is the string
fragmentation model.


title: Neutrino Properties

abstract:
  The experimental discovery that neutrinos almost certainly have masses and
mix raises a number of fundamental questions about the neutrinos. We discuss
what is presently known about the answers to these questions, and how we can
learn more.


title: Gravi-Burst: Super-GZK Cosmic Rays from Localized Gravity

abstract:
  The flux of cosmic rays beyond the GZK cutoff ($\sim 10^{20}$ eV) may be
explained through their production by ultra high energy cosmic neutrinos,
annihilating on the relic neutrino background, in the vicinity of our galaxy.
This process is mediated through the production of a $Z$ boson at resonance,
and is generally known as the $Z$-Burst mechanism. We show that a similar
mechanism can also contribute to the super-GZK spectrum at even higher,
ultra-GZK energies, where the particles produced at resonance are the
Kaluza-Klein gravitons of weak scale mass and coupling from the Randall-Sundrum
(RS) hierarchy model of localized gravity model. We call this mechanism
Gravi-Burst. We discuss the parameter space of relevance to Gravi-Bursts, and
comment on the possibility of its contribution to the present and future
super-GZK cosmic ray data and place bounds on the RS model parameters. Under
certain assumptions about the energy spectrum of the primary neutrinos we find
that cosmic ray data could be potentially as powerful as the LHC in probing the
RS model.


title: Analysis of Long-Lived Slepton NLSP in GMSB model at Linear Collider

abstract:
  We performed an analysis on the detection of a long-lived slepton at a linear
collider with $\sqrt{s}=500$ GeV. In GMSB models a long-lived NLSP is predicted
for large value of the supersymmetry breaking scale $\sqrt{F}$. Furthermore in
a large portion of the parameter space this particle is a stau. Such heavy
charged particles will leave a track in the tracking volume and hit the muonic
detector. In order to disentangle this signal from the muon background, we
explore kinematics and particle identification tools: time of flight device,
dE/dX and Cerenkov devices. We show that a linear collider will be able to
detect long-lived staus with masses up to the kinematical limit of the machine.
We also present our estimation of the sensitivity to the stau lifetime.


title:
Can Precision Measurements of Slepton Masses Probe Right Handed
  Neutrinos?

abstract:
  In a supersymmetric model, the presence of a right handed neutrino with a
large Yukawa coupling $f_{\nu}$ would affect slepton masses via its
contribution to the renormalization group evolution between the grand
unification and weak scales. Assuming a hierarchichal pattern of neutrino
masses, these effects are large for only the third generation of sleptons. We
construct mass combinations to isolate the effect of $f_{\nu}$ from mass
corrections already expected from tau Yukawa couplings. We then analyze the
size of these effects, assuming that the Super-Kamiokande data constrain 0.033
eV $\alt m_{\nu_{\tau}} \alt 0.1$ eV and that neutrino masses arise via a
see-saw mechanism. We also explore whether these effects might be detectable in
experiments at future $e^+e^-$ linear colliders. We find that $m_{\tnu_{\tau}}$
needs to be measured with a precision of about 2-3% to measure the effect of
$f_{\nu}$ if the neutrino and top Yukawa couplings unify at the grand
unification scale. In a simple case study, we find a precision of only 6-10%
might be attainable after several years of operation. If the neutrino Yukawa
coupling is larger, or in more complicated models of neutrino masses, a
determination of $\ttau_1$ and $\tnu_{\tau}$ masses might provide a signal of a
Yukawa interaction of neutrinos.


title: Running couplings in extra dimensions

abstract:
  The regularization scheme dependence of running couplings in extra
compactified dimensions is discussed. We examine several regularization schemes
explicitly in order to analyze the scheme dependence of the Kaluza-Klein
threshold effects, which cause the power law running, in the case of the scalar
theory in five dimensions with one dimension compactified. It is found that in
1-loop order, the net difference in the running of the coupling among the
different schemes is reduced to be rather small after finite renormalization.
An additional comment concerns the running couplings in the warped extra
dimensions which are found to be regularization dependent above TeV scale.


title:
QCD coupling up to third order in standard and analytic perturbation
  theories

abstract:
  We analyze two sets of specific functions, that/which form the basis of the
nonpower asymptotic expansions both in the timelike and spacelike regions for
single scale dependent QCD observables in the Shirkov--Solovtsov's Analytic
Perturbation Theory (APT) free of unphysical singularities. These functions are
explicitly derived up to the third order in the closed form in terms of the
Lambert-W function. As an input we used the exact two loop and the three loop
(corresponding to Pad\'e transformed beta-function) RG solutions for common
invariant coupling \alpha_s. The elegant recurrence formulas, helpful for
numerical analysis, are obtained for the both sets of the APT functions. Then
we construct the global versions of APT functions using the continuity
conditions (at the quark thresholds) on the \alpha_s in the \bar{MS} scheme and
give numerical results. For first three of these functions \mathfrak{A}_n(s)
and {\cal A}_n(Q^2); n=1,2,3 in the large interval of the momentum transfer and
energy (1 GeV <Q,{\sqrt s}< 170 GeV), numerical tables are presented. From
these we observe that, for the timelike arguments, the differences between
functions \mathfrak{A}_n(s) and the corresponding powers of the standard
iteratively approximated coupling \alpha_s^n(s) are not negligible even for
moderate energies in the five--flavor region.


title: Cosmic Strings and Cooper Pairs

abstract:
  It is shown that it is possible for bound fermions on a cosmic string to form
a superconducting state. Due to the attractive force between them, particles
moving in opposite directions along the string form bound pairs. This involves
a similar mechanism to superconductivity in metals at low temperatures. The
method of Gorkov is used to analyse the system. In contrast to the situation in
metals, the unusual properties of the string fermion spectrum allow a massless
Abelian gauge field to provide the required attractive force. This results in
far stronger superconductivity than usual. A massive gauge field can also be
used, in which case the standard results apply.

categories: hep-ph astro-ph cond-mat.supr-con hep-th


title:
Exact analytic two-loop expressions for some QCD observables in the
  time-like region

abstract:
  The author of this work have got explicit expressions for the timelike region
at Next-to-Leading-Order (NLO) as for the coupling function so for QCD
observables. These expressions were compared with approximate ones obtained in
terms of "double logarithms". Next-Next-to-Leading-Order (NNLO) Pade
approximation was also discussed. In this paper some particular role of NLO was
emphasised. It is related with the possibility to express any multi-loop
expressions in terms of the two-loop ones. Thus we can use NLO functions as a
basis of some functional expansion, where higher loop terms incorporation
affects the expansion coefficients only.


title: The Standard Model prediction for eps'/eps

abstract:
  We review fundamental aspects of a new Standard Model analysis of eps'/eps
which takes into account the strong enhancement induced by final state
interactions.


title: B and D Mesons in Lattice QCD

abstract:
  Computational and theoretical developments in lattice QCD calculations of B
and D mesons are surveyed. Several topical examples are given: new ideas for
calculating the HQET parameters \bar{\Lambda} and \lambda_1; form factors
needed to determine |V_{cb}| and |V_{ub}|; bag parameters for the mass
differences of the B mesons; and decay constants. Prospects for removing the
quenched approximation are discussed.


title: Two-Loop Correction to Bhabha Scattering

abstract:
  We present the two-loop virtual QED corrections to e^+ e^- to mu^+ mu^- and
Bhabha scattering in dimensional regularization. The results are expressed in
terms of polylogarithms. The form of the infrared divergences agrees with
previous expectations. These results are a crucial ingredient in the complete
next-to-next-to-leading order QED corrections to these processes. A future
application will be to reduce theoretical uncertainties associated with
luminosity measurements at e^+ e^- colliders. The calculation also tests
methods that may be applied to analogous QCD processes.


title: Phase Transition in Hot Pion Matter

abstract:
  The equation of state for the pion gas is analyzed within the third virial
approximation. The second virial coefficient is found from the pion-pion-
scattering data, while the third one is considered as a free parameter. The
proposed model leads to a first-order phase transition from the pion gas to a
more dense phase at the temperature T_pt < 136 MeV. Due to relatively low
temperature this phase transition cannot be related to the deconfinement. This
suggests that a new phase of hadron matter - 'hot pion liquid' - may exist.


title: Mass Spectrum and the Nature of Neutrinos

abstract:
  Taking as input the best fit solar neutrino anomaly description, MSW LMA, and
the tritium beta decay results we estimate the allowed range of neutrino masses
independently of their nature. Adding the present bound on the effective
neutrino mass coming from neutrinoless double beta decay, we narrow this range
for Majorana neutrinos. We complete the discussion by considering future
perspectives on determining the neutrino masses, when the oscillation data will
be improved and the next experiments on $(\beta\beta)_{0\nu}$ and $^3H$ decay
give new bounds or obtain concrete life-times or distortions in the energy
distribution.


title: Instantaneous Bethe-Salpeter Equation: (Semi-)Analytical Solution

abstract:
  The Bethe-Salpeter equation for bound states of a fermion-antifermion pair in
the instantaneous approximation for the involved interaction kernel is
converted into an equivalent matrix eigenvalue problem with explicitly
(algebraically) given matrices.


title: No-go for exactly degenerate neutrinos at high scale?

abstract:
  We show in a model independent manner that, if the magnitudes of Majorana
masses of neutrinos are exactly equal at some high scale, the radiative
corrections cannot reproduce the observed masses and mixing spectrum at the low
scale, irrespective of the Majorana phases or the mixing angles at the high
scale.


title: Recoil and Threshold Corrections in Short-distance Cross Sections

abstract:
  We identify and resum corrections associated with the kinematic recoil of the
hard scattering against soft-gluon emission in single-particle inclusive cross
sections. The method avoids double counting and conserves the flow of partonic
energy. It reproduces threshold resummation for high-p_T single-particle cross
sections, when recoil is neglected, and Q_T-resummation at low Q_T, when
higher-order threshold logarithms are suppressed. We exhibit explicit resummed
cross sections, accurate to next-to-leading logarithm, for electroweak
annihilation and prompt photon inclusive cross sections.


title:
Measuring the SUSY Breaking Scale at the LHC in the Slepton NLSP
  Scenario of GMSB Models

abstract:
  We report a study on the measurement of the SUSY breaking scale sqrt(F) in
the framework of gauge-mediated supersymmetry breaking (GMSB) models at the
LHC. The work is focused on the GMSB scenario where a stau is the
next-to-lightest SUSY particle (NLSP) and decays into a gravitino with lifetime
c*tau_NLSP in the range 0.5 m to 1 km. We study the identification of
long-lived sleptons using the momentum and time of flight measurements in the
muon chambers of the ATLAS experiment. A realistic evaluation of the
statistical and systematic uncertainties on the measurement of the slepton mass
and lifetime is performed, based on a detailed simulation of the detector
response. Accessible range and precision on sqrt(F) achievable with a counting
method are assessed. Many features of our analysis can be extended to the study
of different theoretical frameworks with similar signatures at the LHC.


title:
Generalized Parton Distributions and the Dependence of Parton
  Distributions on the Impact Parameter

abstract:
  Generalized parton distributions (GPDs) provide a link between form factors,
parton distributions and other observables. I discuss the connection between
GPDs and parton distributions as a function of the impact parameter. Since this
connection involves GPDs in the limit of vanishing skewedness parameter $\xi$,
i.e. when the off-forwardness is purely transverse, I also illustrate how to
relate $\xi\neq 0$ data to $\xi=0$ data, which is important for experimental
measurements of these observables.


title: Event-by-Event Fluctuations from Decay of a Polyakov Loop Condensate

abstract:
  A model for particle production at the deconfining phase transition in QCD is
developed, as the semi-classical decay of a condensate for the Polyakov loop.
In such a model, generically particle production, as measured on an
event-by-event basis, exhibits significant deviations from statistical
behavior.


title: Origin of the Nucleon Electromagnetic Form Factors Dipole Formula

abstract:
  Starting with the VMD parametrization of the electric and magnetic nucleon
form factors, which are saturated just by the ground state vector-mesons rho,
omega and phi, then aplying the strict OZI rule and the asymptotic behaviour of
form factors as predicted by quark model of hadrons, the famous one parameter
dipole formula is derived. By its comparison with space-like data up to t = -5
GeV^2 the most optimal value of the parameter under consideration is
determined. Finaly, charge and magnetization distributions in proton and
neutron are predicted.


title: Experimental status of pionium at CERN

abstract:
  The DIRAC Collaboration presents a first search for "atomic pi(+) pi(-)
pairs" from ionization of pionium.


title: Lepton Flavor Violation at the LHC

abstract:
  Recent results from Super Kamiokande suggest $\nu_\mu-\nu_\tau$ mixing and
hence lepton flavor violation. In supersymmetric models, this flavor violation
may have implications for the pattern of slepton masses and mixings. Possible
signals for this mixing in the decays of sleptons produced at the LHC are
discussed. The sensitivity expected is compared to that of rare decays such as
$\tau\to \mu\gamma$.


title:
Radiatively Induced Neutrino Masses and Oscillations in an
  SU(3)_LxU(1)_N Gauge Model

abstract:
  We have constructed an $SU(3)_L \times U(1)_N$ gauge model utilizing an
$U(1)_{L^\prime}$ symmetry, where $L^\prime$ = $L_e-L_\mu-L_\tau$, which
accommodates tiny neutrino masses generated by $L^\prime$-conserving one-loop
and $L^\prime$-breaking two-loop radiative mechanisms. The generic smallness of
two-loop radiative effects compared with one-loop radiative effects describes
the observed hierarchy of $\Delta m_{atm}^2$ $\gg$ $\Delta m_\odot^2$. A key
ingredient for radiative mechanisms is a charged scalar ($h^+$) that couples to
charged lepton-neutrino pairs and $h^+$ together with the standard Higgs scalar
($\phi$) can be unified into a Higgs triplet as ($\phi^0$, $\phi^-$,
$h^+$)$^T$. This assignment in turn requires lepton triplets ($\psi_L^i$) with
heavy charged leptons ($\kappa_L^{+i}$) as the third member:
$\psi_L^i=(\nu^i_L,\ell^i_L,\kappa^{+i}_L)^T$, where $i$ ($=1,2,3$) denotes
three families. It is found that our model is relevant to yield quasi-vacuum
oscillations for solar neutrinos.


title: Large Mixing Angle MSW Solution in U(1) Flavor Symmetry

abstract:
  We have discussed the quark-lepton mass matrices with the U(1) flavor
symmetry in SU(5), which lead to the large mixing angle MSW solution of solar
neutrinos. The solar neutrino solution depends on the next-leading terms in the
neutrino mass matrix. We have found the lepton mass matrices with the
$U(1)\times Z_2$ symmetry, which give the LMA-MSW solution uniquely. The
coefficients of the matrix elements of the charged leptons are constrained
strongly due to the bound of $U_{e3}$ in the CHOOZ experiment.


title:
The V-A sum rules and the Operator Product Expansion in complex
  q^2-plane from tau-decay data

abstract:
  The operator product expansion (OPE) for the difference of vector and axial
current correlators is analyzed for complex values of momentum q^2. The vector
and axial spectral functions, taken from hadronic tau-decay data, are treated
with the help of Borel, Gaussian and spectral moments sum rules. The range of
applicability, advantages and disadvantages of each type are discussed. The
general features of OPE are confirmed by the data. The vacuum expectation
values of dimension 6 and 8 operators are found to be O_6=-(6.8\pm 2.1)*10^{-3}
GeV^6, O_8=(7\pm 4)*10^{-3} GeV^8.


title: The t->WZb decay in the Standard Model: A Critical Reanalysis

abstract:
  We compute the t->WZb decay rate, in the Standard Model, at the leading order
in perturbation theory, with special attention to the effects of the finite
widths of the W and Z bosons. These effects are extremely important, since the
t->WZb decay occurs near its kinematical threshold. They increase the value of
the decay rate by orders of magnitude near threshold or allow it below the
nominal threshold. We discuss a procedure to take into account the finite-width
effects and compare the results with previous studies of this decay. Within the
Standard Model, for a top quark mass in the range between 170 and 180 GeV, we
find BR(t->WZb) ~ 2 x 10^{-6}, which makes the observation at the LHC very
difficult if at all possible.


title: Extended HQEFT Lagrangian and currents

abstract:
  From the tree-level heavy quark effective Lagrangian keeping
particle-antiparticle mixed sectors we derive the vector current coupling to a
hard gluonic field allowing for heavy quark-antiquark pair annihilation and
creation.


title: Quest for the dynamics of $\nu_{mu} \to \nu_{tau}$ conversion

abstract:
  We perform a quantitative analysis of the capability of K2K, MINOS, OPERA and
a neutrino factory in a muon collider to discriminate the standard mass induced
vacuum oscillation from the pure decoherence solution to the atmospheric
neutrino problem and thereby contribute to unravel the dynamics that governs
the observed $\nu_mu$ disappearence.


title: Fluctuations of the Metric Tensor and Fermion Propagators

abstract:
  Conformal fluctuations of the metric tensor at the Planck scale are
considered. They give rise to a lower bound of the proper length. This leads to
finite expressions for quantities related to propagators without the need of
renormalization or regularization. Quantities like the current quark mass or
the effective strong coupling constant have to be reinterpreted.


title: Multiplicity of different hadrons in e+e-, pp, and AA collisions

abstract:
  Employing the recently developed neXus model, we compare the yields of
different hadrons in ultra-relativistic collisions: electron-positron
annihilation at 91 GeV, proton-proton scattering at 17 GeV and nucleus-nucleus
collisions at 17 GeV (SPS) and 200 GeV (RHIC). Plotting the yields as a
function of the hadron masses, we find very surprising results: we observe that
the spectra are practically identical for e+e- at 91 GeV and central
nucleus-nucleus reactions at SPS and RHIC energies, whereas the spectrum for
proton-proton scattering is somewhat steeper. All have the form one expects if
the particles were emitted by a canonical system which is characterized by a
temperature and chemical potentials. These identical forms have, however,
different origins: in e+e- and pp the exponential shape it is due to the
statistical behavior of string fragmentation, which has absolutely nothing to
do with thermalization, in AA it is caused by phase space. The fact that e+e-
and nuclear results agree is pure coincidence. Surprisingly the results for pp
and e+e- differ, although here the production mechanism is identical. In pp
collisions we see directly that the string energy is very limited and hence the
high mass baryons are suppressed. We conclude that it is practically impossible
to draw conclusions from hadronic yields about the reaction mechanism.


title: Comment on "No Primordial Magnetic Field from Domain Walls"

abstract:
  We comment on the recent preprint hep-ph/0007123 by M.B. Voloshin, claiming
that domain walls are diamagnetic. We show that the results presented therein
are based on an incorrect treatment of the zero mode contribution to the vacuum
energy density. We also shown that the correct treatment leads to the
conclusion that domain walls are ferromagnetic, and can generate a primordial
magnetic field.


title: On the Emerging Phenomenology of <(A_\mu)^2>

abstract:
  We discuss phenomenology of the vacuum condensate <(A_\mu)^2> in pure gauge
theories, where A_\mu is the gauge potential. Both Abelian and non-Abelian
cases are considered. In case of the compact U(1) the non-perturbative part of
the condensate <(A_\mu)^2> is saturated by monopoles. In the non-Abelian case,
a two-component picture for the condensate is presented according to which
finite values of order \Lambda_{QCD}^2 are associated both with large and short
distances. We obtain a lower bound on the <(A_\mu)^2> by considering its change
at the phase transition. Numerically, it produces an estimate similar to other
measurements. Possible physical manifestations of the condensate are discussed.


title: Neutrino mass spectrum and lepton mixing

abstract:
  The program of reconstruction of the neutrino mass and flavor spectrum is
outlined and the present status of research is summarized. We describe the role
of future solar and atmospheric neutrino experiments, detection of the Galactic
supernovae and double beta decay searches in accomplishing this program. The
LSND result and four neutrino mass spectra are considered in connection with
recent searches for the sterile components in the solar and atmospheric
neutrino fluxes.


title: Neutrinos and the Standard Model

abstract:
  Since their "discovery" by Pauli in 1930, neutrinos have plaed a key part in
confirmation of the structure of the standard model of strong and electroweak
interactions. After reviewing ways in which this has been manifested in the
past, we discuss areas in which neutrinos continue to play this role.


title: Compact Variables and Singular Fields in QCD

abstract:
  Subject of our investigations is QCD formulated in terms of physical degrees
of freedom. Starting from the Faddeev-Popov procedure, the canonical
formulation of QCD is derived for static gauges. Particular emphasis is put on
obstructions occurring when implementing gauge conditions and on the
concomitant emergence of compact variables and singular fields. A detailed
analysis of non-perturbative dynamics associated with such exceptional field
configurations within Coulomb- and axial gauge is described. We present
evidence that compact variables generate confinement-like phenomena in both
gauges and point out the deficiencies in achieving a satisfactory
non-perturbative treatment concerning all variables. Gauge fixed formulations
are shown to constitute also a useful framework for phenomenological studies.
Phenomenological insights into the dynamics of Polyakov loops and monopoles in
confined and deconfined phases are presented within axial gauge QCD


title: When can long-range charge fluctuations serve as a QGP signal?

abstract:
  We critically discuss recent suggestion to use long-range modes of charge
(electric or baryon) fluctuations as a signal for the presence of Quark-Gluon
Plasma at the early stages of a heavy ion collision. We evaluate the rate of
diffusion in rapidity for different secondaries, and argue that for conditions
of the SPS experiments, it is strong enough to relax the magnitude of those
fluctuations almost to its equilibrium values, given by hadronic ``resonance
gas''. We further argue that experimental data from SPS agree with this
conclusion. We evaluate the detector acceptance needed to measure such
``primordial'' long-range fluctuations at RHIC conditions. We conclude with an
application of the charge fluctuation analysis to the search for the QCD
critical point.


title: Signatures of Thermal Dilepton Radiation at RHIC

abstract:
  The properties of thermal dilepton production from heavy-ion collisions in
the RHIC energy regime are evaluated for invariant masses ranging from 0.5 to 3
GeV. Using an expanding thermal fireball to model the evolution through both
quark-gluon and hadronic phases various features of the spectra are addressed.
In the low-mass region, due to an expected large background, the focus is on
possible medium modifications of the narrow resonance structures from $\omega$
and $\phi$ mesons, whereas in the intermediate-mass region the old idea of
identifying QGP radiation is reiterated including effects of chemical
under-saturation in the early stages of central Au+Au collisions.


title: Moduli Evolution in Heterotic Scenarios

abstract:
  We discuss several aspects of the cosmological evolution of moduli fields in
heterotic string/M-theory scenarios. In particular we study the equations of
motion of both the dilaton and overall modulus of these theories in the
presence of an expanding Universe and under different assumptions. First we
analyse the impact of their couplings to matter fields, which turns out to be
negligible in the string and M-theory scenarios. Then we examine in detail the
possibility of scaling in M-theory, i.e. how the moduli would evolve naturally
to their minima instead of rolling past them in the presence of a dominating
background. In this case we find interesting and positive results, and we
compare them to the analogous situation in the heterotic string.


title: Experimental Probes of the Randall-Sundrum Infinite Extra Dimension

abstract:
  The phenomenological possibilities of the Randall-Sundrum non-compact extra
dimension scenario with the AdS horizon increased to approximately a millimeter
length, corresponding to an effective brane tension of TeV^4, are investigated.
The corrections to the Newtonian potential are found to be the only
observationally accessible probe of this scenario, as previously suggested in
the literature. In particular, the presence of the continuum of KK modes does
not lead to any observable collider signatures. The extent to which
experimental tests of Newtonian gravity can distinguish this scenario from the
scenario of Arkani-Hamed, Dimopoulos, and Dvali with one and two millimeter
size extra dimensions is explicitly demonstrated.


title:
Hadronic cross-sections in gamma gamma processes and the next linear
  collider

abstract:
  In this note we address the issue of theoretical estimates of the hadronic
cross-sections for \gamgam processes. We compare the predictions of the minijet
model with data as well as other models, highlighting the band of uncertainties
in the theoretical predictions as well as those in the final values of the
$\sigma (\gamgam \go {\rm hadrons})$ extracted from the data. We find that the
rise of $\sigma_{\gamma \gamma}^{\rm tot}$ with energy shown in the latest
\gamgam data is in tune with the faster rise expected in the Eikonal Minijet
Models (EMM). We present an estimate of the accuracy with which this
cross-section needs to be measured, in order to distinguish between the
different theoretical models which try to `explain ' the rise of total
cross-sections with energy. We find that the precision of measurement required
to distinguish the EMM type models from the proton-like models, for $300 <
\sqrt{s}_{\gamgam} < 500$ GeV, is $\lsim 20 %$, whereas to distinguish between
various proton-like models or among the different parametrizations of the EMM,
a precision of $\lsim 8-9 %$ or $\lsim 6-7%$ respectively, is required. We also
comment briefly on the implications of these predictions for hadronic
backgrounds at the next linear collider (NLC) to be run in the \gamgam mode or
\eplem mode.


title: Probing For New Physics In J/$\Psi$ Decays

abstract:
  Beijing Spectrometer (BES) at Beijing Electron Positron Collider (BEPC), IHEP
has accumulated 2.5 $\times 10^7$ J/$\Psi$ and plans to increase the number to
$10^8 \sim 10^9$ in the near future. In this paper I review and summarize the
recent studies on the possibilities of probing for new physics at BES. This
includes the theoretical works on and experimental attempt performed at BES in
searching for flavor changing neutral current, CP violation and lepton flavor
violation in the processes of J/$\Psi$ decays.


title: Weak decays of Heavy mesons

abstract:
  I explore the possibility of using heavy meson decays as probes for flavour
changing neutral transitions (FCNC) $c\to u\gamma$ and $c\to ul^+l^-$. In the
standard model, these are the most frequent FCN transitions among the quarks
with charge $2/3e_0$. I predict the short and long distance contributions to
the relevant heavy meson decays within the standard model and explore their
sensitivity to different scenarios of physics beyond the standard model. The
rare $B_c\to B_u^*\gamma$ decay is proposed as the most suitable case study of
the $c\to u\gamma$ transition and is studied with the ISGW model. Its detection
at the branching ratio much higher than $10^{-8}$ would signal new physics.
Weak decays of charm mesons to a light meson and a photon or a charged lepton
pair are also studied for this purpose. Their probabilities are found to be
dominated by the long distance contributions and raise our hopes that they may
be detected soon. A window of opportunity to probe the $c\to ul^+l^-$
transition is found in the decay $D\to \pi l^+l^-$, at the kinematical region
of high di-lepton mass. In order to study the charm meson decays, I adapt the
Heavy Meson Chiral Lagrangian approach and demonstrate for its applicability by
predicting the charm meson nonleptonic decay rates.


title:
Enhancement of epsilon'/epsilon in the SU(2)_L times SU(2)_R times U(1)
  model

abstract:
  We explore the possible enhancement of direct CP violating parameter
epsilon'/epsilon in the general left-right model based on the SU(2)_L times
SU(2)_R times U(1) gauge group. The mixing matrix of right-handed quarks,
V_{CKM}^R is observable in the left-right model, and provides new source of CP
violating phase. We calculate the parameter epsilon'/epsilon in the left-right
model and show that the new phases from V_{CKM}^R can yield the sizable
contribution to the direct CP violation enough to satisfy the recent
measurements of Re(epsilon'/epsilon) from Fermilab KTeV and CERN NA48
experiments.


title:
A generalized Bell-Inequality and Decoherence for the
  K^0\bar{K^0}-System

abstract:
  First a generalized Bell-inequality for different times and for different
quasi-spin states is developed. We focus on special quasi-spin eigenstates and
times. The inequality based on a local realistic theory is violated by the
CP-violating parameter, if the quantum theory is used to recalculate the
probabilities. Next the quantum mechanical probabilities are modified by the
decoherence approach which enables the initial state to factorize
spontaneously. In this way we get a lower limit for the decoherence parameter
\zeta, which measures the degree of decoherence. This result is compared with
the experimental value of the decoherence parameter \zeta deduced from the data
of the CPLEAR-experiment.


title: Implications of sigma models in the standard model and beyond

abstract:
  After a brief introduction to the sigma model in QCD, we discuss how the
sigma model can be relevant in the Standard Model. It is shown to be useful in
the analysis of weak processes, such as the study of $\Delta {I} = 1/2$ rule,
and in the analysis of the Higgs sector as well. The sigma model description is
also shown to be quite useful in searching for the effects of New Physics via
gauge boson self-interactions.


title:
Strongly Distorted Baryon Wave-Functions: Hyperon Beta-Decay and the
  Spin of the Lambda and the Nucleon

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 have no (or only small) symmetry
breaking components. In this framework we study the $g_A/g_V$ ratios for
hyperon beta-decay as well as the various quark flavor components of the axial
charge of the nucleon and the $\Lambda$-hyperon.


title: The Influence of Dimension Eight Operators on Weak Matrix Elements

abstract:
  I describe recent work with V. Cirigliano and E. Golowich on the effect of
dimension eight operators on weak nonleptonic amplitudes. The basic message is
that there is an inconsistency in the way that many calculations are
traditionally performed. If one calculates matrix elements involving only
physics below some scale \mu, then one needs dimension eight operators
explicitly in the weak OPE. On the other hand if one wants to use dimensional
regularization throughout, then one needs all scales to be included within the
matrix element, and this results in the same net effect. A numerical estimate
indicates that this is important below \mu= 2 GeV, and this calls into question
many of the models that have been used to predict \epsilon'/\epsilon.


title: Bottomonia Hadroproduction

abstract:
  We analyze Tevatron data of bottomonium hadroproduction in the framework of
the colour-octet model (COM) implemented in the event generator PYTHIA using
CTEQ4L PDF taking into account initial-state radiation of gluons and
Altarelli-Parisi evolution of final-state gluons. We obtain new values for the
colour-octet matrix elements relevant to this production process for the
Upsilon(nS) family (n=1,2,3), finding that the ^1S_0^{(8)}+^3P_J^{(8)}
contributions are not needed in the fit. We show the different contributions to
Upsilon(1S) production at Tevatron for p_T>8 GeV, comparing them with CDF data.
Finally we extrapolate to LHC energies to predict Upsilon(nS) production rates.


title: More Corrections to the Higgs Mass in Supersymmetry

abstract:
  In supersymmetry, the Higgs quartic couplings is given by the sum in
quadrature of the weak gauge couplings. This leads to the prediction of a light
Higgs boson, which still holds when considering loop corrections from soft
supersymmetry breaking. However, another source of corrections, which
explicitly depends on the scale of the mediation of supersymmetrey breaking, is
from generic hard breaking terms. We show that these corrections can
significantly modify the Higgs mass prediction in models of low-energy
supersymmetry breaking, for example, gauge mediation. Conversely, the Higgs
mass measurement can be used to constrain the scale of mediation of
supersymmetry breaking.


title: QCD string in mesons and baryons

abstract:
  Field distributions generated by static quark-antiquark and QQQ sources are
calculated analytically in the framework of Gaussian (bilocal) approximation of
Field Correlator Method (FCM). Special attention is paid to the QQQ system and
asymmetric configurations are also studied. In both quark-antiquark and QQQ
cases the string consists mainly of longitudinal color electric field.
Transverse color electric field contribution is shown to be less then 3%.
Baryon string has an Y-like shape with a deep well at the string junction
position. Field distributions for quark-diquark and for three quarks on one
line are considered. The interaction potential for quarks forming an
equilateral triangle is calculated. The material of the paper is illustrated by
24 3D colored pictures.


title:
Branching ratios for B_{d,s}->J/psi eta and B_{d,s}->eta l+l-,
  extracting gamma from B_{d,s}->J/psi eta, and possibilities for constraining
  C_{10A} in semileptonic B decays

abstract:
  Estimates of the branching ratios for B_{d,s}->J/psi eta and B_{d,s}->eta
l+l- are obtained by SU(3) relation to B_d->J/psi K and B_d->K l+l-,
respectively, as functions of the eta mixing parameter, theta_P. Based on these
estimates, a discussion of the prospects for HERA-B, CDF-II, and ATLAS on these
processes is given. The CP violation in B_{d,s}-> J/psi eta is analyzed in
depth and a method to extract the angle gamma of the unitarity triangle is
discussed. Finally, a possible method to constrain the Wilson coefficient
C_{10A} from measurements on semileptonic B decays such as B_d->J/psi K and
B_s->eta l+l- is proposed along with a discussion of the prospects for future
experiments and form factor calculations to reach the precision required for
this method to be interesting.


title:
Implications of the ALEPH tau-Lepton Decay Data for Perturbative and
  Non-Perturbative QCD

abstract:
  We use ALEPH data on hadronic $\tau$ decays in order to calculate Euclidean
coordinate space correlation functions in the vector and axial-vector channels.
The linear combination $V-A$ receives no perturbative contribution and is
quantitatively reproduced by the instanton liquid model. In the case of $V+A$
the instanton calculation is in good agreement with the data once perturbative
corrections are included. These corrections clearly show the evolution of
$\alpha_s$. We also analyze the range of validity of the Operator Product
Expansion (OPE). In the $V-A$ channel we find a dimension $d=6$ contribution
which is comparable to the original SVZ estimate, but the instanton model
provides a different non-singular term of the same magnitude. In the $V+A$ case
both the OPE and the instanton model predict the same $d=4$ power correction
induced by the gluon condensate, but it is masked by much larger perturbative
contributions. We conclude that the range of validity of the OPE is limited to
$x\lsim0.3$ fm, whereas the instanton model describes the data over the entire
range.


title: Remarks on models with singlet neutrino in large extra dimensions

abstract:
  Small Dirac masses for neutrinos are natural in models with singlet fermions
in large extra dimensions with quantum gravity scale M_{\ast} \sim 1- 100 TeV.
We study two modifications of the minimal model in order to obtain the mass
scale relevant for atmospheric neutrino oscillations with at most O(1)
higher-dimensional Yukawa couplings and with M_{\ast} \sim a few TeV. 1) In
models with singlet fermions in smaller number of extra dimensions than
gravity, we find that the effects on BR (\mu \to e \gamma) and on
charged-current universality in \pi^- \to e \bar{\nu}, \mu \bar{\nu} decays are
suppressed as compared to that in the minimal model with neutrino and gravity
in the same space. 2) If small Dirac masses for the singlets are added along
with lepton number violating couplings, then the mass scales and mixing angles
for neutrino oscillations can be different from those relevant for \mu \to e
\gamma and \pi^- \to e \bar{\nu}, \mu \bar{\nu}. Thus, in both modified models
the constraints on M_{\ast} from BR (\mu \to e \gamma) and \pi^- \to e
\bar{\nu}, \mu \bar{\nu} decays can be significantly relaxed. Furthermore,
constraints from supernova 1987a strongly disfavor oscillations of active
neutrinos to sterile neutrinos in both the minimal and the modified models.


title: Constraints on Gauged B-3L_tau and Related Theories

abstract:
  We consider extensions of the Standard Model with an extra U(1) gauge boson
which couples to B-(alpha L_e + beta L_mu + gamma L_tau) with alpha + beta +
gamma = 3. We show that the extra gauge boson necessarily mixes with the Z
leading to potentially significant corrections to the Z-f-fbar vertex. The
constraints on the size of this correction imposed by the Z-pole data from LEP
and SLD are derived.


title: Polarized and Unpolarized Structures of the Virtual Photon

abstract:
  We discuss the structure functions and the parton distributions in the
virtual photon target, both polarized and unpolarized, beyond the leading order
in QCD. We study the factorization-scheme dependence of the parton
distributions.


title: Photons and static gravity

abstract:
  The influence of static gravitational field on frequency, wave-length and
velocity of photons and on the energy levels of atoms and nuclei is considered
in the most elementary way. The interconnection between these phenomena is
stressed.


title:
The decay of the observed $J^{PC}=1^{-+}$ (1400) and
  $J^{PC}=1^{-+}$(1600) hybrid candidates

abstract:
  We study the possible interpretation of the two exotic resonances $J^{PC}=
1^{-+}$ at 1400 and 1600 MeV, claimed to be observed by BNL, decaying
respectively into $\eta\pi$, $\eta'\pi$, $f_{1}\pi$ and $\rho\pi$. These
objects are interpreted as hybrid mesons, in the quark-gluon constituent model
using a chromoharmonic confining potentiel.
  The quantum numbers $J^{PC}I^{G} = 1^{-+} 1^{-}$ can be considered in a
constituent model as an hybrid meson ($q \bar q g$). The lowest $J^{PC}=
1^{-+}$states may be built in two ways : $l_{g}$=1 (gluon-excited)
corresponding to an angular momentum between the gluon and ($q \bar q$) system,
while $l_{q \bar q}=1$ (quarks-excited) corresponds to an angular momentum
between $q$ and $\bar q$. For the gluon-excited mode $1^{-+}$ hybrids, we find
the decay dominated by the $b_{1}\pi$ channel, and by the $\rho \pi$ channel
for the quark-excited mode. In our model, neither the quark-excited nor the
gluon-excited $1^{-+}$ (1400 MeV) hybrids can decay into $\eta\pi$ and
$\eta'\pi$, in contradiction with experiment. Hence, the 1400 MeV resonance
seems unlikely to be an hybrid state. The $1^{-+}$ (1600 MeV) gluon-excited
hybrid is predicted with too large a total decay width, to be considered as an
hybrid candidate. On the contrary the quark-excited mode has a total decay
width around 165 MeV, with a $\rho \pi$ preferred decay channel, in agreement
with BNL. Our conclusion is that {\it{this resonance may be considered as a
hybrid meson in the quark-excited mode}}


title:
A phenomenological description of $K\to\pi\pi\gamma$ magnetic
  transitions

abstract:
  A phenomenological analysis of $K\to \pi\pi\gamma$ ($K_L\to\pi^+\pi^-\gamma$
and $K^+\to\pi^+\pi^0\gamma$) with the direct emission photon is carried out
beyond the leading order in the chiral perturbation theory. We show that the
experimental evidence for the large photon energy dependence of the magnetic
amplitude in $K_L\to\pi^+\pi^-\gamma$ seems to indicate an interesting
consequence: vector meson dominance must be implemented at $O(p^4)$, which is
not a general feature of the chiral perturbation theory. The phenomenology of
$K^+\to\pi^+\pi^0\gamma$ is also analyzed using the same scheme.


title:
Magnetic catalysis in a P-even, chiral-invariant three-dimensional model
  with four-fermion interaction

abstract:
  The influence of an external constant and homogeneous magnetic field H on the
phase structure of the P-symmetric, chiral invariant 3-dimensional field theory
model with two four-fermion interaction structures is considered. An arbitrary
small (nonzero) magnetic field is shown to induce spontaneous violation of the
initial symmetry (magnetic catalysis). Moreover, vacuum of the model at H>0 can
be either P-symmetric or chiral invariant, depending on the values of the
coupling constants.


title: Vacuum Instability in Anomaly Mediation Models with Massive Neutrinos

abstract:
  We study the vacuum stability in the anomaly mediated supersymmetry (SUSY)
breaking models with massive neutrinos. It is shown that, because of the
seesaw-induced mass terms for neutrinos, the true vacuum has a large negative
cosmological constant provided that the vacuum where we now live has an
(almost) vanishing cosmological constant. Although the quantum transition into
the true vacuum from our false vacuum is highly suppressed, the thermal
transition at high temperatures may not be neglected because of the thermal
excitations. However, we find that the thermal transition is, in fact,
negligibly small and hence the anomaly mediation models are cosmologically
safe. Thus, we conclude that the reheating temperature T_R could be very high
(e.g. T_R >> 10^10 GeV) in the anomaly mediation models even with the
seesaw-induced mass terms for neutrinos.


title: Weak and Electromagnetic Interactions of Hyperons: a Chiral Approach

abstract:
  A range of issues in the field of weak and electromagnetic interactions of
hyperons is presented from the perspective of (broken) chiral symmetry,
together with an assessment of where important challenges remain.


title: Sterile Neutrino and Accelerating Universe

abstract:
  If all three neutrino oscillation data were to be confirmed in the near
future, it is probable that one might need a sterile neutrino, in addition to
the three active ones. This sterile neutrino, nu_S, would be very light with
mass m_{nu_S} less than or equal to 1 eV or even with m_{\nu_S} approximately
10^{-3} eV according to some scenarios. Why would it be so light? On another
front, recent cosmological observations and analyses appear to indicate that
the present universe is flat and accelerating, and that the present energy
density is dominated by a ``dark variety'', with rho_V approximately
(10^{-3}eV)^4. Is it a constant? Is there a link between these apparently
unrelated phenomena?


title: A Variational Fock-Space Treatment of Quarkonium

abstract:
  The variational method and the Hamiltonian formalism of QCD are used to
derive relativistic, momentum space integral equations for a quark-antiquark
system with an arbitrary number of gluons present. As a first step, the
resulting infinite chain of coupled equations is solved in the nonrelativistic
limit by an approximate decoupling method. Comparison with experiment allows us
to fix the quark mass and coupling constant, allowing for the calculation of
the spectra of massive systems such as charmonium and bottomonium. Studying the
results with and without the nonAbelian terms, we find that the presence of the
nonAbelian factors yields better agreement with the experimental spectra.


title: Gluon contribution to the structure function g_2(x,Q^2)

abstract:
  We calculate the one-loop twist-3 gluon contribution to the flavor-singlet
structure function g_2(x,Q^2) in polarized deep-inelastic scattering and find
that it is dominated by the contribution of the three-gluon operator with the
lowest anomalous dimension (for each moment N). The similar property was
observed earlier for the nonsinglet distributions, although the reason is in
our case different. The result is encouraging and suggests a simple evolution
pattern of g_2(x,Q^2) in analogy with the conventional description of twist-2
parton distributions.


title: Nucleon Polarizabilities

abstract:
  The subject of nucleon polarizabilities in real, virtual, and doubly virtual
Compton scattering is discussed with respect to what is known and how such
quantities can be extracted from data.


title: New Value of M_mu/M_e from Muonium Hyperfine Splitting

abstract:
  The complete contribution to the muonium hyperfine splitting of relative
order alpha^3(m_e/m_mu)ln(alpha) is calculated. The result amounts to 0.013
kHZ, much smaller than suggested by a previous estimate, and leads to a 2-sigma
shift of the most precise value for the muon-electron mass ratio, with the
error reduced by approximately 30%. Analogous contributions are calculated for
the positronium hyperfine splitting:
(217/90-17*ln{2}/3)m_e(alpha^7/pi)ln(1/alpha) \approx -0.32 MHz; the remaining
theoretical uncertainty should be well below experimental error, leaving
discrepancies of 2.5-sigma and 3.5-sigma with the two most precise
measurements.


title:
O(alpha^3 ln alpha) corrections to muonium and positronium hyperfine
  splitting

abstract:
  We compute O(alpha^3 ln alpha) relative corrections to the ground state
hyperfine splitting of a QED two body bound state with different masses of
constituents. The general result is then applied to muonium and positronium. In
particular, a new value of the muon to electron mass ratio is derived from the
muonium ground state hyperfine splitting.


title:
Calculation of fragmentation functions in two-hadron semi-inclusive
  processes

abstract:
  We investigate the properties of interference fragmentation functions arising
from the emission of two leading hadrons inside the same jet for inclusive
lepton-nucleon deep-inelastic scattering. Using an extended spectator model for
the mechanism of the hadronization, we give a complete calculation and
numerical estimates for the examples of a proton-pion pair produced with
invariant mass on the Roper resonance, and of two pions produced with invariant
mass close to the $\rho$ mass. We discuss azimuthal angular dependence of the
leading order cross section to point up favourable conditions for extracting
transversity from experimental data.


title: QCD sum rule analysis of the charmonium system: The charm quark mass

abstract:
  In this work, the charm quark mass is obtained from a QCD sum rule analysis
of the charmonium system. In our investigation we include results from
non-relativistic QCD at next-to-next-to-leading order. Using the pole mass
scheme, we obtain a value of $M_c=1.70\pm 0.13$ GeV for the charm pole mass.
The introduction of a potential-subtracted mass leads to an improved scale
dependence. The running ${\rm \MSb}$-mass is then determined to be
$m_{c}(m_{c}) = 1.23 \pm 0.09$ GeV.


title:
Leading logarithmic contribution to the second-order Lamb shift induced
  by the loop-after-loop diagram

abstract:
  Contribution of order \alpha^2 (Z \alpha)^6 \ln^3(Z \alpha)^{-2} to the
ground-state Lamb shift in hydrogen induced by the loop-after-loop diagram is
evaluated analytically. An additional contribution of this order is found
compared to the previous calculation by Karshenboim [JETP 76, 541 (1993)]. As a
result, an agreement is achieved for this correction between different
numerical and analytical methods.