title:
Approximation of the Schwinger--Dyson and the Bethe--Salpeter Equations
  and Chiral Symmetry of QCD

abstract:
  The Bethe--Salpeter equation for the pion in chiral symmetric models is
studied with a special care to consistency with low-energy relations. We
propose a reduction of the rainbow Schwinger--Dyson and the ladder
Bethe--Salpeter equations with a dressed gluon propagator. We prove that the
reduction preserves the Ward--Takahashi identity for the axial-vector current
and the PCAC relation.


title:
Relic neutrino asymmetries and big bang nucleosynthesis in a four
  neutrino model

abstract:
  Oscillations between ordinary and sterile neutrinos can generate large
neutrino asymmetries in the early universe. These asymmetries can significantly
affect big bang nucleosynthesis (BBN) through modification of nuclear reaction
rates. We study this phenomenon within a model consisting of the three ordinary
neutrinos plus one sterile neutrino that can be motivated by the neutrino
anomalies and the dark matter problem. We calculate how the lepton asymmetries
produced evolve at temperatures where they impact on BBN. The effect of the
asymmetries on primordial helium production is determined, leading to an
effective number of neutrino flavours during BBN of either about 2.7 or 3.1
depending on the sign of the lepton asymmetry.


title: Inelastic Final-State Interactions of $B \to VV \to \pi K$ Processes

abstract:
  We study the final-state interactions in $B \to \pi K$ decays through $B \to
VV \to \pi K$ processes where the inelastic rescattering occurs via single pion
exchange. The next-to-leading order low energy effective Hamiltonian and BSW
model are used to evaluate the weak transition matrix elements and the
final-state interactions. We found that the final-state interaction effects in
$B \to \rho K^* \to \pi K$ processes are significant. The Fleischer-Mannel
relation about the CKM angle $\gamma$ may be significantly modified.


title: Anomaly Induced Domain Formation of Disoriented Chiral Condensates

abstract:
  We discuss the effect of chiral anomaly as a possible mechanism for
triggering formation of domains of disoriented chiral condensate (DCC) in
relativistic heavy ion collisions. The anomalous $\pi^0 \to 2 \gamma$ coupling
and the strong, Lorentz contracted electromagnetic fields of the heavy ions
combine to produce the ``anomaly kick'' to the field configuration of the
neutral pion field. We implement the effect of anomaly kick in our numerical
simulation of the linear sigma model in a schematic way which preserves its
characteristic features: the effect is coherent over a large region of space
but is opposite in sign above and below the ion scattering plane. We
demonstrate by detailed simulations with longitudinal expansion that the DCC
domain formation is dramatically enhanced by the anomaly kick in spite of its
small absolute magnitude. We examine the behavior of various physical
quantities such as pion fields, the axial vector currents, and their
correlation functions. Our results also provide useful insight into the
mechanism and properties of DCC domain formation, in general. Finally, we
discuss some experimental observables which can signal the anomaly induced
formation of DCC.


title:
Diffractive-Like (or Parametric-Resonance-Like?) Enhancement of the
  Earth (Day-Night) Effect for Solar Neutrinos Crossing the Earth Core

abstract:
  It is shown that the strong enhancement of the Earth (day-night) effect for
solar neutrinos crossing the Earth core in the case of the small mixing angle
MSW electron neutrino to muon (tau) neutrino transition solution of the solar
neutrino problem is due to a new resonance effect in the solar neutrino
transitions in the Earth and not just to the MSW effect in the core. The effect
is in many respects similar to the electron paramagnetic resonance. The
conditions for existence of this new resonance effect are discussed. They
include specific constraints on the neutrino oscillation lengths in the Earth
mantle and in the Earth core, thus the resonance is a ``neutrino oscillation
length resonance''. The effect exhibits strong dependence on the neutrino
energy. Analytic expression for the probability accounting for the solar
neutrino transitions in the Earth, which provides a high precision description
of the transitions, including the new resonance effect, is derived. The
implications of our results for the searches of the day-night asymmetry in the
solar neutrino experiments are briefly discussed. The new resonance effect is
operative also in the muon neutrino to electron neutrino (electron neutrino to
muon neutrino) transitions of atmospheric neutrinos crossing the Earth core.


title:
Covariant Model of Relativistic Extended Particles based on the
  Oscillator Representation of the Poincar\'e Group

abstract:
  While internal space-time symmetries of relativistic particles are dictated
by the little groups of the Poincar\'e group, it is possible to construct
representations of the little group for massive particles starting from
harmonic oscillator wave functions for the quark model. The resulting
oscillator wave functions are covariant and can be Lorentz-boosted. It is thus
possible to obtain the parton model by boosting the quark model. A review of
Wigner's theory of the little groups is given. It is shown that the covariant
oscillator wave functions become squeezed as as the system becomes boosted. It
is shown also that the Lorentz-squeezed quark distribution exhibits the
peculiarities of Feynman's parton model including the lack of coherence in the
calculation of cross sections. A historical review of the concept of covariance
is given.

categories: hep-ph hep-th math-ph math.MP nucl-th quant-ph


title: Measuring the Broken Phase Sphaleron Rate Nonperturbatively

abstract:
  We present details for a method to compute the broken phase sphaleron rate
(rate of hot baryon number violation below the electroweak phase transition)
nonperturbatively, using a combination of multicanonical and real time lattice
techniques. The calculation includes the ``dynamical prefactor,'' which
accounts for prompt recrossings of the sphaleron barrier. The prefactor depends
on the hard thermal loops, getting smaller with increasing Debye mass; but for
realistic Debye masses the effect is not large. The baryon number erasure rate
in the broken phase is slower than a perturbative estimate by about exp(-3.6).
Assuming the electroweak phase transition has enough latent heat to reheat the
universe to the equilibrium temperature, baryon number is preserved after the
phase transition if the ratio of (``dimensionally reduced'' thermal) scalar to
gauge couplings (lambda / g^2) is less than .037.


title: Imaginary part of the electromagnetic lepton form factors

abstract:
  The charge $F_1(0)$ and the magnetic $F_2(0)$ form factors of heavy charged
leptons have been shown in the framework of the perturbation theory to have
imaginary part. The imaginary parts of the form factors for muon and tau lepton
have been calculated at the two-loop level in the Standard Model. The effects
where these imaginary parts could manifest themselves are discussed.


title: Implications of a Minimal SO(10) Higgs Structure

abstract:
  A minimal SO(10) Higgs structure involving a single adjoint field along with
spinors, vectors and singlets has been shown to break the SO(10) gauge symmetry
to the standard model while stabilizing the F-flat directions and solving the
doublet-triplet splitting problem naturally. With this minimal set of Higgs
fields, we show how to construct quark and lepton mass matrices which explain
well the many features of the observed spectrum, including the Georgi-Jarlskog
mass relations. A large mixing of the muon- and tau-neutrinos results naturally
as observed in the atmospheric neutrino data. A particular model relying on a
family symmetry has been constructed which realizes the desired mass matrices.


title: Standard-Model-like Chiral Spectra and the Origin of the Families

abstract:
  We outline our approach to understand the family structure through the idea
of a SM-like chiral fermion spectrum, one that is derivable from anomaly
cancellation conditions in the same way as the one family SM, under an extended
symmetry, which after breaking to the SM symmetry yields the three families as
the residual chiral content. An example of a relatively simple scalar sector
which gives an acceptable symmetry breaking pattern and naturally hierarchical
quark mass matrices is also discussed for a successful $SU(4)_A\otimes
SU(3)_C\otimes SU(2)_L\otimes U(1)_X$ model. This is a summary of a seminar
given at the 37th IUKT winter school, for the proceedings.


title:
Diffractive Production of Jets and Weak Bosons, and Tests of
  Hard-Scattering Factorization

abstract:
  We extract diffractive parton densities from data on diffractive deep
inelastic scattering (DIS) and on diffractive photoproduction of jets. We
explore the results of several ansaetze for the functional form of the parton
densities. Then we use the fitted parton densities to predict the diffractive
production of jets and of W's and Z's in p-pbar collisions at the Tevatron. To
fit the photoproduction data requires a large gluon density in the Pomeron. The
predictions for the Tevatron cross sections are substantially higher than data;
this signals a breakdown of hard-scattering factorization in diffractive
hadron-hadron collisions.


title: Where is the antimatter

abstract:
  The antimatter exists everywhere, but under suppressed state. So its
appearance is nothing but the various effects of special relativity.


title: The b quark low-scale running mass from Upsilon sum rules

abstract:
  The b quark low-scale running mass m_kin is determined from an analysis of
the Upsilon sum rules in the next-to-next-to-leading order (NNLO). It is
demonstrated that using this mass one can significantly improve the convergence
of the perturbation series for the spectral density moments. We obtain m_kin(1
GeV) = 4.56 \pm 0.06 GeV. Using this result we derive the value of the MS-bar
mass m: m(m) = 4.20 \pm 0.1 GeV. Contrary to the low-scale running mass, the
pole mass of the b quark cannot be reliably determined from the sum rules. As a
byproduct of our study we find the NNLO analytical expression for the cross
section e+e- --> Q\bar Q of the quark antiquark pair production in the
threshold region, as well as the energy levels and the wave functions at the
origin for the ^1S_3 bound states of Q\bar Q.


title:
Light-cone path integral approach to the Landau-Pomeranchuk-Migdal
  effect and the SLAC data on bremsstrahlung from high energy electrons

abstract:
  The recent data of the SLAC E-146 collaboration on the
Landau-Pomeranchuk-Migdal effect for bremsstrahlung from 8 and 25 GeV electrons
are analyzed within a rigorous light-cone path integral approach. Numerical
calculations have been carried out treating rigorously the Coulomb effects and
including the inelastic processes. Comparison with the experimental data is
performed taking into account multi-photon emission and photon absorption. For
most of the targets the theoretical predictions are in excellent agreement with
the experimental data.


title:
Parametric resonance of neutrino oscillations and passage of solar and
  atmospheric neutrinos through the earth

abstract:
  We present an exact analytic solution to the neutrino evolution equation in
matter with periodic step-function density profile and discuss in detail the
parametric resonance of neutrino oscillations that can occur in such a system.
Solar and atmospheric neutrinos traversing the earth pass through layers of
alternating density and can therefore experience parametric resonance of their
oscillations. Atmospheric neutrinos can undergo parametrically enhanced
oscillations in the earth when their trajectories deviate from the vertical by
about $26^\circ - 32^\circ$. Solar neutrinos traversing the earth can
experience a strong parametric resonance of their oscillations in a wide range
of zenith angles. If the small mixing angle MSW effect is the solution of the
solar neutrino problem, the oscillations of solar neutrinos crossing the core
of the earth {\em must} undergo strong parametric resonance; this phenomenon
should facilitate significantly the observation of the day-night effect in
oscillations of solar neutrinos. If observed, the enhanced day-night effect for
core crossing neutrinos would therefore confirm both the MSW solution of the
solar neutrino problem and the parametric resonance of neutrino oscillations.


title: Shifting $R_b$ with $A^b_{FB}$

abstract:
  Precision measurements at the $Z$ resonance agree well with the standard
model. However, there is still a hint of a discrepancy, not so much in $R_b$ by
itself (which has received a great deal of attention in the past several years)
but in the forward-backward asymmetry $A^b_{FB}$ together with $R_b$. The two
are of course correlated. We explore the possibilty that these and other
effects are due to the mixing of $b_L$ and $b_R$ with one or more heavy quarks.


title:
Effects of R-parity Violating Couplings on CP Asymmetries in Neutral B
  Decays

abstract:
  A detailed analysis of the effects of supersymmetric models without R-parity
on various CP asymmetries in neutral $B$ decays is given. We concentrate on
models with Abelian horizontal symmetries that allow us to estimate the order
of magnitude of the new effects. We focus on channels where the Standard Model
gives clean predictions: $ B_{d}\to\psi K_{S} $ and $B_{d}\to\phi K_{S}$. The
two asymmetries can have a value different from $\sin2\beta.$ Moreover, they
can be different from each other.


title: New Limits on the SUSY Higgs Boson Mass

abstract:
  We present new upper limits on the light Higgs boson mass mh in
supersymmetric models. We consider two gravity-mediated models (with and
without universal scalar masses) and two gauge-mediated models (with a 5+5 or
10+10 messenger sector). We impose standard phenomenological constraints, as
well as SU(5) Yukawa coupling unification. Requiring that the bottom and tau
Yukawa couplings meet at the unification scale to within 15%, we find the upper
limit mh<114 GeV in the universal supergravity model. This reverts to the usual
upper bound of 125 GeV with a particular nonuniversality in the scalar
spectrum. In the 5+5 gauge-mediated model we find mh<97 GeV for small tan beta
and mh = 116 GeV for large tan beta, and in the 10+10 model we find mh<94 GeV.
We discuss the implications for upcoming searches at LEP-II and the Tevatron.


title:
Topological defects and conditions for baryogenesis in the Left-Right
  symmetric model

abstract:
  It is shown that the minimal Left-Right symmetric model admits cosmic string,
domain wall and conditionally, monopole solutions. The strings arise when the
$SU(2)_R$ is broken and can either be destabilized at the electroweak scale or
remain stable through the subsequent breakdown to $U(1)_{EM}$. The monopoles
and domain wall configurations exist in the $SU(2)_L\otimes U(1)_Y$ symmetric
phase and disappear after subsequent symmetry breaking. Their destabilization
provides new sources of non-equilibrium effects below the electroweak scale.
Several defect-mediated mechanisms for low energy baryogenesis are shown to be
realisable in this model.


title:
Possible Explanation Why \tau_{B^{\pm}}\sim\tau_{B^0} But
  \tau_{D^{\pm}}\sim \tau_{D^0}

abstract:
  Data show that \tau_{B^{\pm}}\sim\tau_{B^0}, but \tau_{D^{\pm}}\sim
2\tau_{D^0}. The naive interpretation which attributes \tau_{D^{\pm}}\sim
2\tau_{D^0} to a destructive interference between two quark diagrams for
D^{\pm} decays, definitely fails in the B-case. We investigate Close and
Lipkin's suggestion that the phases for producing radially excited states
\psi_{2s} in the decay products of B-mesons can possess an opposite sign to the
integrals for \psi_{1s} decay products. Their contributions can partially
compensate each other to result in \tau_{B^{\pm}}\sim\tau_{B^0}. Since D-mesons
are much lighter than B-mesons, such possibilities do not exist in D-decays.


title:
The running coupling method with next-to-leading order accuracy and
  pion, kaon elm form factors

abstract:
  The pion and kaon electromagnetic form factors $F_M(Q^2)$ are calculated at
the leading order of pQCD using the running coupling constant method. In
calculations the leading and next-to-leading order terms in
$\alpha_S((1-x)(1-y)Q^2)$ expansion in terms of $\alpha_S(Q^2)$ are taken into
account. The resummed expression for $F_M(Q^2)$ is found. Results of numerical
calculations for the pion (asymptotic distribution amplitude) are presented.


title: NLL Resummation for Dijet Production

abstract:
  We discuss threshold resummation for dijet production in hadronic collisions.
Resummation to next-to-leading logarithmic (NLL) accuracy is given in terms of
an anomalous dimension matrix for each partonic subprocess involved.


title: The $\pi-$Gluon Exchange Interaction Between Constituent Quarks

abstract:
  The interaction mediated by irreducible pion and gluon exchange between
constituent quarks is calculated and shown to have a strong tensor component,
which tends to cancel the pion exchange tensor interaction between quarks. Its
spin-spin component is somewhat weaker than the pion exchange spin-spin
interaction, while its central and spin-orbit components are small in
comparison to the corresponding single gluon exchange interactions. The
combination of the $\pi-$gluon exchange interaction with the single pion
exchange interaction and a weak gluon exchange interaction between constituent
quarks has the qualitative features required for understanding the hyperfine
splittings of the spectra of the nucleon and the $\Delta$ resonances.


title: A Mechanism for Ordinary-Sterile Neutrino Mixing

abstract:
  Efficient oscillations between ordinary (active) and sterile neutrinos can
occur only if Dirac and Majorana mass terms exist which are both small and
comparable. It is shown that this can occur naturally in a class of string
models, in which higher-dimensional operators in the superpotential lead to an
intermediate scale expectation value for a scalar field and to suppressed Dirac
and Majorana fermion masses.


title:
Four-fermion interactions and sgoldstino masses in models with a
  superlight gravitino

abstract:
  We discuss the role of the effective interactions among four matter fermions
in supersymmetric models with a very light gravitino. We show that, from a
field-theoretical viewpoint, no model-independent bound on the gravitino mass
can be derived from such interactions. Making use of a naturalness criterion,
however, we are able to derive some interesting but not very stringent bounds,
complementary to those obtained from the direct production of supersymmetric
particles. We also show that, generically, masses for the spin-0 partners of
the goldstino (sgoldstinos) of the order of the gravitino mass and much smaller
than squark and slepton masses do not obey a naturalness criterion.


title:
The light-cone gauge and the calculation of the two-loop splitting
  functions

abstract:
  We present calculations of next-to-leading order QCD splitting functions,
employing the light-cone gauge method of Curci, Furmanski, and Petronzio (CFP).
In contrast to the `principal-value' prescription used in the original CFP
paper for dealing with the poles of the light-cone gauge gluon propagator, we
adopt the Mandelstam-Leibbrandt prescription which is known to have a solid
field-theoretical foundation. We find that indeed the calculation using this
prescription is conceptionally clear and avoids the somewhat dubious
manipulations of the spurious poles required when the principal-value method is
applied. We reproduce the well-known results for the flavour non-singlet
splitting function and the N_C^2 part of the gluon-to-gluon singlet splitting
function, which are the most complicated ones, and which provide an exhaustive
test of the ML prescription. We also discuss in some detail the x=1 endpoint
contributions to the splitting functions.


title: Electromagnetic Shocks in Strong Magnetic Fields

abstract:
  We examine the propagation of electromagnetic radiation through a strong
magnetic field using the method of characteristics. Owing to nonlinear effects
associated with vacuum polarization, such waves can develop discontinuities
analogous to hydrodynamical shocks. We derive shock jump conditions and discuss
the physical nature of these non-linear waves


title:
Constant versus Field Dependent Gauge Couplings in Supersymmetric
  Theories

abstract:
  We briefly discuss the differences between considering the gauge coupling as
a constant or as a field, the dilaton, in N=1 supersymmetric theories. We
emphasize the differences regarding supersymmetry breaking. Recent developments
on the nonperturbative dynamics of these theories provide new ideas on the
induced dilaton potential and its stabilization.


title: Hadron Spectroscopy in Regge Phenomenology

abstract:
  We show that linear Regge trajectories for mesons and baryons, and the cubic
mass spectrum associated with them, determine expressions for the hadron masses
in terms of the universal Regge slope \alpha' alone. The ground state hadron
masses as calculated from these expressions are in excellent agreement with
experiment for \alpha'=0.85 GeV^{-2}.


title: Heavy Baryon Production and Decay

abstract:
  The branching ratio B(Lambda_c -> p K- pi+) normalizes the production and
decay of charmed and bottom baryons. At present, this crucial branching ratio
is extracted dominantly from B.bar -> baryons analyses. This note questions
several of the underlying assumptions and predicts sizable B.bar -> D(*) N
N'.bar X transitions, which were traditionally neglected. It predicts
B(Lambda_c -> p K- pi+) to be significantly larger (0.07 +/- 0.02) than the
world average. Some consequences are briefly mentioned. Several techniques to
measure B(Lambda_c -> p K- pi+) are outlined with existing or soon available
data samples. By equating two recent CLEO results, an appendix obtains B(D0 ->
K- pi+)= 0.035 +/- 0.002, which is somewhat smaller than the current world
average.


title: Exotic massive hadrons and ultra-high energy cosmic rays

abstract:
  We investigate the proposal that primary cosmic rays of energy above the
Greisen-Zatsepin-Kuzmin cutoff are exotic massive strongly interacting
particles (uhecrons). We study the properties of air showers produced by
uhecrons and find that masses in excess of about 50 GeV are inconsistent with
the highest energy event observed. We also estimate that with sufficient
statistics a uhecron of mass as low as 10 GeV may be distinguished from a
proton.


title:
Cornering gauge-mediated supersymmetry breaking with quasi-stable
  sleptons at the Tevatron

abstract:
  There are many theoretical reasons why heavy quasi-stable charged particles
might exist. Pair production of such particles at the Tevatron can produce
highly ionizing tracks (HITs) or fake muons. In gauge-mediated supersymmetry
breaking, sparticle production can lead to events with a pair of quasi-stable
sleptons, a significant fraction of which will have the same electric charge.
Depending on the production mechanism and the decay chain, they may also be
accompanied by additional energetic leptons. We study the relative importance
of the resulting signals for the Tevatron Run II. The relative fraction of
same-sign tracks to other background-free signals is an important diagnostic
tool in gauge-mediated supersymmetry breaking that may provide information
about mass splittings, tan(beta) and the number of messengers communicating
supersymmetry breaking.


title: Meson Correlators at Finite Temperature

abstract:
  We evaluate equal time point to point spatial correlation functions of
mesonic currents at finite temperature. For this purpose we consider the QCD
vacuum structure in terms of quark antiquark condensates and their fluctuations
in terms of an irreducible four point structure of the vacuum. The temperature
dependence of quark condensates is modeled using chiral perturbation theory for
low temperatures and lattice QCD simulations near the critical temperature.We
first consider the propagation of quarks in a condensate medium at finite
temperature. We then determine the correlation functions in a hot medium.
Parameters such as mass, coupling constant and threshold energy are deduced
from the finite temperature correlators. We find that all of them decrease
close to the critical temperature.


title: Gravitational coupling of neutrinos in a medium

abstract:
  In a medium that contains electrons but not the other charged leptons, such
as normal matter, the gravitational interactions of neutrinos are not the same
for all the neutrino flavors. We calculate the leading order matter-induced
corrections to the neutrino gravitational interactions in such a medium and
consider some of their physical implications.


title: Angular structure of energy losses of hard jet in dense QCD-matter

abstract:
  Angular structure of radiative and collisional energy losses of a hard parton
jet propagating through dense QCD-matter is investigated. For small angular jet
cone sizes, $\theta_0 < 5^0$, the radiative energy loss is shown to dominate
over the collisional energy loss due to final state elastic rescattering of the
hard projectile on thermal particles in the medium. Due to coherent effects,
the radiative energy loss decreases with increasing the angular size the jet.
It becomes comparable with the collisional energy loss for $\theta_0 >
5^0-10^0$.


title:
Vacuum oscillations and variations of solar neutrino rates in
  SuperKamiokande and Borexino

abstract:
  The vacuum oscillation solution to the solar neutrino problem predicts
characteristics variations of the observable neutrinos rates, as a result of
the L/E_nu dependence of the nu_e survival probability (L and E_nu being the
neutrino pathlength and energy, respectively). The E_nu-dependence can be
studied through distortions of the recoil electron spectrum in the
SuperKamiokande experiment. The L-dependence can be investigated through a
Fourier analysis of the signal in the SuperKamiokande and Borexino experiments.
We discuss in detail the interplay among such observable variations of the
signal, and show how they can help to test and constrain the vacuum oscillation
solution(s). The analysis includes the 374-day SuperKamiokande data.


title:
Interpolation Formulas for the Eta-Gamma and Eta'-Gamma Transition Form
  Factors

abstract:
  The new CLEO and LEP data on the eta-gamma and eta'-gamma transition form
factors have renewed the interest in simple interpolation formulas, valid at
any value of momentum transfer. We are going to show that recent theoretical
and phenomenological results on eta-eta' mixing lead to two-pole forms, where
each pole term resembles the Brodsky/Lepage interpolation formula for the
pi-gamma case and depends on the mixing and decay parameters in a simple
fashion. The parameters, entering the occasionally used one-pole formulas, on
the other hand, cannot be interpreted theoretically in a simple way.


title: Q^2-evolution of spin-dependent parton densities

abstract:
  We discuss the NLO evolution of quark transversity densities and of the
parton distribution function for linearly polarized gluons in a linearly
polarized hadron. A supersymmetric relation between the NLO evolution kernels
for transversity and for linear polarization is found. We also study the
implications of NLO evolution for Soffer's inequality and the prospects of
measuring transversity densities in polarized Drell-Yan at RHIC.


title: Baryonic systems with charm and bottom in the bound state soliton model

abstract:
  The binding energies of baryonic systems (BS) with baryon number $B=2, 3$ and
4 possessing heavy flavor, charm and bottom, are estimated within the rigid
oscillator version of the bound state approach to chiral soliton models. Two
tendencies are noted: the binding energy increases with increasing mass of the
flavor and with increasing $B$. Therefore, the charmed or bottomed baryonic
systems have more chances to be bound than strange baryonic systems discussed
previously. The flavor symmetry breaking in decay constants $F$ is considered
which is especially important for baryonic systems with bottom quantum numbers.
Generally, for heavy flavors the scale of the binding energies of BS depends on
the scale of flavor symmetry violation in $r_F=F_F/F_\pi$.


title: Evolution of the Light Cone Distribution Function for a Heavy Quark

abstract:
  We compute the one-loop anomalous dimension for the light cone distribution
function of a heavy quark and solve the corresponding evolution equation
analytically. Some implications of the results for inclusive $B$ decays are
discussed.


title: Heavy Quarks and Structure Functions

abstract:
  I present a method for calculating heavy quark production which extrapolates
smoothly from the well understood limits of the fixed-flavour number scheme for
Q^2 approx m_H^2 to the zero-mass scheme at Q^2/m_H^2 -> infinity. For all Q^2
> m_H^2 the evolution of the heavy quark distribution is precisely as in the
massless MSbar scheme. The method is simple to implement and compares well with
data.


title: Leading ln(1/x) and Heavy Quark Corrections in Structure Functions

abstract:
  I present a calculation of structure functions at leading order which
includes an unambiguous inclusion of the leading ln(1/x) terms for each power
of alpha_s, and also the correct effects due to the mass of the charm and
bottom quarks. I compare the results of fits to data to those obtained using
conventional NLO in alpha_s calculations, noting a clear preference for my
approach, especially at small x. The predictions for both the charm structure
function and F_L(x,Q^2) using the two approaches are compared, the latter being
much more discriminating.


title: Regulating the Baryon Asymmetry in No-Scale Affleck-Dine Baryogenesis

abstract:
  In supergravity models (such as standard superstring constructions) that
possess a Heisenberg symmetry, supersymmetry breaking by the inflationary
vacuum energy does not lift flat directions at tree level. One-loop corrections
give small squared masses that are negative (about -g^2 H^2/(4\pi)^2) for all
flat directions that do not involve the stop. After inflation, these flat
directions generate a large baryon asymmetry; typically $n_B/s \sim$ O(1). We
consider mechanisms for suppressing this asymmetry to the observed level. These
include dilution from inflaton or moduli decay, GUT nonflatness of the $vev$
direction, and higher dimensional operators in both GUT models and the MSSM. We
find that the observed BAU can easily be generated when one or more of these
effects is present.


title: Weak Semileptonic Decays of Heavy Baryons Containing Two Heavy Quarks

abstract:
  In the heavy quark limit a heavy baryon which contains two heavy quarks is
believed to be composed of a heavy diquark and a light quark. Based on this
picture, we evaluate the weak semileptonic decay rates of such baryons. The
transition form factors between two heavy baryons are associated with those
between two heavy mesons by applying the superflavor symmetry. The effective
vertices of the W-boson and two heavy diquarks are obtained in terms of the
Bethe-Salpeter equation. Numerical predictions on these semileptonic decay
widths are presented and they will be tested in the future experiments.


title: Electroweak Baryogenesis in the Presence of an Isosinglet Quark

abstract:
  We consider the possibility of electroweak baryogenesis in a simple extension
of the standard model with an extra singlet complex scalar and a vector-like
down quark. We show that in the present model the first-order electroweak phase
transition can be strong enough to avoid the baryon asymmetry washout by
sphalerons and that the CP-violating effects can be sufficient to explain the
observed baryon-to-entropy ratio nB/s ~ 10^(-10). Other appealing features of
the model include the generation of a CKM phase from spontaneous CP breaking at
a high energy scale and a possible solution of the strong CP problem through
the natural suppression of the parameter theta.


title: QCD Anatomy of B -> X_s gamma Decays

abstract:
  We present an updated next-to-leading order analysis of the B -> X_s gamma
branching ratio and photon spectrum, including consistently the effects of
Fermi motion in the heavy-quark expansion. For the Standard Model, we obtain
B(B -> X_s gamma) = (2.57+-0.26^{+0.31}_{-0.36}) * 10^{-4} for the integral
over the high-energy part of the photon spectrum with E_gamma^{lab} > 2.2 GeV,
where the first error reflects the uncertainty in the input parameters, and the
second one the uncertainty in the calculation of Fermi motion. This prediction
agrees with the CLEO measurement of the same quantity within one standard
deviation. From a reanalysis of the CLEO data, we obtain for the total
branching ratio B(B -> X_s gamma) = (2.62+-0.60_{exp}^{+0.37}^{-0.30{th}}) *
10^{-4} using the measured rate above 2.2 GeV, and
(2.66+-0.56_{exp}^{+0.43}_{-0.48{th}}) * 10^{-4} using a fit to the photon
energy spectrum. Both values are consistent with the Standard Model prediction
of (3.29+-0.33) * 10^{-4}. Our analysis contains an improved discussion of
renormalization scale dependence and QED corrections. We also discuss the
sensitivity of the branching ratio and photon spectrum to hadronic parameters
such as the b-quark mass, and to possible contributions from New Physics beyond
the Standard Model.


title: \Lambda_b \to \Lambda_c P(V) Nonleptonic Weak Decays

abstract:
  The two-body nonleptonic weak decays of \Lambda_b \to \Lambda_c P(V) (P and V
represent pseudoscalar and vector mesons respectively) are analyzed in two
models, one is the Bethe-Salpeter (B-S) model and the other is the hadronic
wave function model. The calculations are carried out in the factorization
approach. The obtained results are compared with other model calculations.


title:
Neutrino oscillations in a $3\nu_L+3\nu_R$ framework with five light
  neutrinos

abstract:
  We propose a neutrino mass matrix model in which five neutrino species remain
light through the seesaw mechanism within a supersymmetric $3\nu_L+3\nu_R$
framework. We construct such a model based on the nonrenormalizable terms in
the superpotential constrained by the discrete symmetry which may be expected
in the models at the high energy scale such as superstring. We study the
possible oscillation phenomena by fixing mass parameters so as to explain the
solar and atmospheric neutrino deficits and also include a candidate of the
suitable dark matter. We also discuss the charged lepton mass matrix based on
this neutrino model. LSND results may be consistently explained within this
model.


title: Chiral Symmetry for Positive and Negative Parity Nucleons

abstract:
  Chiral properties of positive and negative parity nucleons, N and N*$, are
studied from the viewpoint of chiral symmetry. Two possible ways to assign
chiral transformations to the negative parity nucleon are considered. Using
linear sigma models based on the two chiral realizations, theoretical as well
as phenomenological consequences of the two different assignments are
investigated. We find that the nucleon mass in the chiral restored phase is the
key quantity to determine the meson-nucleon couplings and the axial charges of
nucleons. We also discuss the role of chiral symmetry breaking in the mass
splitting of N and N* in the two sigma models.


title: Rare Decay of K Meson

abstract:
  We investigate the rare decay processes of the K mesons, K_{L,S} -> \pi^0 \nu
\bar{\nu} and K^{+} -> \pi^+ \nu \bar{\nu} in LR model with lepton family
number being well conserved. In these processes, scalar operators
(\bar{s}d)(\bar{\nu}_{\tau}\nu_{\tau}), which are derived from box diagram in
LR model, play an important role due to an enhancement factor M_{K}/m_{s} in
the matrix element $<\pi|\bar{s}d|K>$. It is emphasized that the K_{L} decay
process through the scalar operator is not the CP violating mode, so the B(K_L
-> \pi^{0} \nu \bar{\nu}) remains non-zero even in the CP conserved limit. We
present the pion energy spectrum for these processes and discuss the effects of
LR model.


title:
Violation of the factorization theorem in large angle radiative Bhabha
  scattering

abstract:
  The lowest order QED radiative corrections to the radiative large angle
Bhabha scattering process in the region where all kinematic invariants are
large compared to the electron mass are considered. We show that the leading
logarithmic corrections do not factorize before the Born cross section,
contrary to the picture assumed in the renormalization group approach. The
leading and non leading contributions for typical kinematics of the hard
process at the energy of the $\Phi$ factory are estimated.


title:
Chiral quark model analysis of nucleon quark sea isospin asymmetry and
  spin polarization

abstract:
  We analyze recent measurements of the nucleon quark sea isospin asymmetry in
terms of the chiral quark model. The new measurements indicate that the SU(3)
model with modest symmetry breaking and no $\eta'$ Goldstone boson gives a
satisfactory description of data. We also discuss the matching parameter for
the axial-vector current. Finally, we analyze the nucleon quark spin
polarization measurements directly in the chiral quark model without using any
SU(3) symmetry assumption on the hyperon axial-vector form factors. The new
data indicate that the chiral quark model gives a remarkably good and
consistent description of all low energy baryon measurements.


title: Status of twist-2 operator dimensions at O(1/N_f)

abstract:
  We review the computation of the anomalous dimensions of the twist-2
unpolarized operators in the large N_f expansion. Results are discussed for the
predominantly gluonic singlet operator and the O(1/N_f) part of the 3-loop
splitting function is given.


title: Fitting direct interaction pieces into neutrino puzzles

abstract:
  We develop a framework and unified, compact notation to include neutrino
direct interaction effects with neutrino oscillations for a wide class of
low-energy, effective four-Fermi interactions. Modest flavor-violating
interaction strengths can make significant changes in the boundaries in $\Delta
M^2 \leftrightarrow sin^2 2\theta$ and in $tan^2 \theta_{13} \leftrightarrow
tan^2 \theta_{23} parameter space. We draw examples from the L-R symmetric and
$MSSM + \slash R$ models and find the recently reported decay-at-rest $\mu
\leftrightarrow e$ transition probability can be described without oscillations
in L-R symmetric models.


title: The Asymptotics of Pion Charge Form Factor

abstract:
  The asymptotics of pion charge form factor is obtained in the framework of
relativistic Hamiltonian dynamics for the infinite value limit of momentum
transfer and zero value limit of constituent--quark mass. It is shown that this
asymptotics is the same as given by the perturbative QCD and is determined by
relativistic kinematics only, being independent on the constituent quarks
interaction in pion.


title:
One-loop Weak Dipole Form Factors and Weak Dipole Moments of Heavy
  Fermions

abstract:
  The one-loop weak-magnetic and weak-electric dipole form factors of heavy
fermions in a generic model are derived. Numerical predictions for the $\tau$
lepton and $b$ quark Weak Anomalous Magnetic and Electric Dipole Moments (AWMDM
and WEDM) in the SM and MSSM are reviewed. The MSSM contribution to the $\tau$
($b$) AWMDM could be, in the high $\tan\beta$ scenario, four (thirty) times
larger than the Electroweak SM one, but still a factor five below the QCD
contribution (in the $b$ case). More interesting is the CP-odd sector where the
contribution to the $\tau$ ($b$) WEDM in the MSSM could be up to twelve orders
of magnitude larger than in the SM.


title: Fermion Masses without Yukawa Couplings

abstract:
  Radiatively generated fermion masses without tree level Yukawa couplings are
re-analyzed within supersymmetric models. Special emphasis is given to the
possible appearance of color and charge breaking vacua. Several scenarios in
which the radiative mechanism can be accomodated for the first, second, and
third generation fermion masses are presented. Some of these require a low
scale of supersymmetry breaking.


title: Corrections at Small x

abstract:
  We show that the all order summation of small x logarithms cannot be included
in the Q^2 evolution of structure functions because the NLLx corrections
overwhelm the LLx contribution.


title: The Spin Structure of a Polarized Photon

abstract:
  We show that the first moment of the spin-dependent structure function
$g_1^{\gamma}(x,Q^2)$ of a real photon vanishes independent of the momentum
transfer $Q^2$ it is probed with. This result is non-perturbative: it holds to
all orders in perturbation theory in abelian and non-abelian gauge theory and
at every twist.


title: Dynamical SUSY Breaking with a Hybrid Messenger Sector

abstract:
  In this paper we present a dynamical model of SUSY breaking with a hybrid
messenger sector. SUSY is broken dynamically at a scale of order $10^9$ GeV via
strong SU(2) gauge interactions. SUSY breaking is then transmitted to the
observable sector via two distinct sources: (1) messengers, carrying Standard
Model gauge quantum numbers, with the messenger mass of order
  $10^{15}$ GeV, and (2) the D term of an anomalous U(1)$_X$. The model is
quite constrained. The messenger scale is fixed by the Fayet-Iliopoulos term
for the anomalous U(1)$_X$ interaction. In addition, we show that the D term
SUSY breaking contributions to squark and slepton masses are "naturally" the
same order as those coming from the messengers.


title: Probing Top-Quark Couplings at Polarized NLC

abstract:
  The energy spectrum of the lepton(s) in e^+e^- --> tt-bar --> l^{+-}
...../l^+l^-..... at next linear colliders (NLC) is studied for arbitrary
longitudinal beam polarizations as a possible test of new physics in top-quark
couplings. The most general non-standard couplings for gamma-tt-bar, Ztt-bar
and Wtb vertices are considered. Expected precision of the
non-standard-parameter determination is estimated applying the
optimal-observable procedure.


title:
Relation between Scattering and Production Amplitudes - concerning sigma
  Particle in pi pi System -

abstract:
  In a series of previous papers the present authors and collaborators have
shown strong evidence for existence of the long-sought sigma-particle by
analyzing the pi pi-scattering and pi pi-production processes, applying,
respectively, the IA method and the VMW method. In this paper we examine the
relation between the scattering amplitude T and the production amplitude F from
the viewpoint of the unitarity and the final state interaction (FSI) theorem by
using a simple field theoretical model. As a result it is shown that the
amplitudes in the physical state representation are directly represented
through the Breit-Wigner amplitudes of the relevant resonances, and the
respective forms of T and F coincide with those in the IA and VMW methods,
justifying our methods of analyses.


title: Phenomenology and cosmology of weakly coupled string theory

abstract:
  The weakly coupled vacuum of $E_8\otimes E_8$ heterotic string theory remains
an attractive scenario for phenomenolgy and cosmology. The particle spectrum is
reviewed and the issues of gauge coupling unification, dilaton stabilization
and modular cosmology are discussed. A specific model for condensation and
supersymmetry breaking, that respects known constraints from string theory and
is phenomenologically viable, is described.


title: Elastic Meson Production - Factorisation and Gauge Invariance

abstract:
  The factorisation of the hard amplitude for exclusive meson production in
deep inelastic scattering is considered in the framework of a simple model. It
is demonstrated explicitly how gauge invariance ensures the cancellation of
non-factorising contributions.


title: Associated quantities from the CCFM approach

abstract:
  Results are presented on structure functions and final state properties
within the CCFM approach. Traditionally used forms of the CCFM equation have
difficulty fitting the F_2 data, predicting too fast a growth at small x. A
solution can be found in a particular treatment of formally subleading (1-z)
terms, which dampens very considerably the small-x growth. Preliminary results
are shown for the transverse energy flow, and future prospects and plans are
discussed.


title: The Milan factor for jet-shape observables

abstract:
  This talk discusses and explains the two-loop corrections, also known as the
Milan factor, for power corrections to jet-shape observables.


title: Semi-inclusive Pion Production and the d/u Ratio

abstract:
  We explore the feasibility of directly extracting the large-x valence d/u
ratio through a measurement of pions in the current fragmentation region of
semi-inclusive deep-inelastic scattering from protons.


title: ``Good-Walker'' + QCD dipoles = Hard Diffraction

abstract:
  The Good-Walker mechanism for diffraction is shown to provide a link between
total and diffractive structure functions and to be relevant for QCD
calculations at small x_{Bj}. For Deep-Inelastic scattering on a small-size
target (cf. an onium) the r\^ ole of Good-Walker ``diffractive eigenstates'' is
played by the QCD dipoles appearing in the $1/N_C$ limit of QCD. Hard
diffraction is thus related to the QCD tripe-dipole vertex which has been
recently identified (and calculated) as being a conformal invariant correlator
and/or a closed-string amplitude. An extension to hard diffraction at HERA via
$k_T-$factorisation of the proton vertices leads to interesting phenomenology.


title: kt-factorization predictions for F2c at HERA

abstract:
  High energy factorization predictions for F2c are derived using BFKL
resummations of leading logs for the proton structure functions at HERA. A
theoretical non-perturbative uncertainty on the factorization scheme is taken
into account by considering two different approaches for modelling the proton.
The parameters are fixed by a fit of F2 at small x. The resulting predictions
for F2c are in agreement with the data within the present error bars.


title:
Final-state radiation and line-shape distortion in resonance pair
  production

abstract:
  In this letter it is shown how final-state QED corrections to the production
of a pair of resonances can distort the line shape of such a resonance in a
sizeable way. This effect depends on the definition of the line shape and can
reach up to 30%, depending on the final state. The mechanism is first displayed
for a particular case of ZZ production, for which an exact and approximate
treatment can be given. The approximate method is then applied to W-pair
production. In addition some simple rules of thumb are given for accurately
estimating the characteristic distortion effects, like the mass shift and peak
reduction.


title: Radiation zeros and scalar particles beyond the standard model

abstract:
  Standard radiation zeros arise from the factorization properties of
tree-level amplitudes involving a massless photon and can occur when all
charged particles in the initial and final state have the same sign. We
investigate how several different processes involving new scalar particles
beyond the standard model may exhibit radiation zeros and how this structure
might be exploited to probe their electromagnetic structure. We focus on (i)
unnoticed aspects of angular zeros in the process e- + e- --> Delta-- + gamma
for doubly charged Higgs boson (or any bilepton) production and (ii) the
process gamma + e- --> q + S/V for scalar (S) or vector (V) leptoquarks (LQs).
We also discuss how factorized amplitudes and radiation zeros may appear in the
gauge boson fusion production of non-conjugate leptoquark pairs via gamma + W
--> S_i + S_j* in high energy ee reactions and how the zeros affect the
production cross-sections for various types of scalar leptoquarks.


title:
Limits on a Strong Electroweak Sector from e^+ e^- -> 2gamma + missing E
  at LEP2

abstract:
  We study the process $e^+ e^- \to \gamma \gamma \nu \bar{\nu}$ in the context
of a strong electroweak symmetry breaking model, which can be a source of
events with two photons and missing energy at LEP2. We investigate bounds on
the model assuming that no deviation is observed from the Standard Model within
a given experimental error.


title: Diffraction Association and Flavoring of Pomeron

abstract:
  The most important consequence of Pomeron being a pole is the factorization
property. However, due to Pomeron intercept being greater than 1, the
extrapolated single diffraction dissociation cross section based on a classical
triple-Pomeron formula is too large leading to a potential unitarity violation
at Tevatron energies. It is our desire here to point out that the "flavoring"
of Pomeron plays the dominant role in resolving this apparent "paradox".


title:
Bethe-Salpeter Equation for Heavy Baryons \omega_{Q}^{(*)} in the
  Diquark Picture

abstract:
  In the heavy quark limit, the heavy baryons \omega_{Q}^{(*)} (\omega could be
\Sigma, \Xi or \Omega and Q=b or c) are regarded as composed of a heavy quark
and an axial vector, light diquark with good spin and isospin quantum numbers.
Based on this diquark picture we establish the Bethe-Salpeter (B-S) equation
for \omega_{Q}^{(*)} in the limit where the heavy quark has infinite mass, m_Q
-> \infty. It is found that in this limit there are three components in the B-S
wave function for \omega_{Q}^{(*)}. Assuming the kernel to consist of a scalar
confinement term and a one-gluon-exchange term we derive three coupled integral
equations for the three B-S scalar functions in the covariant instantaneous
approximation. Numerical solutions for the three B-S scalar functions are
presented, including a discussion about their dependence on the various input
parameters. These solutions are applied to calculate the Isgur-Wise functions
\xi (\omega) and \zeta (\omega) for the weak transitions \Omega_{b}^{(*)} \to
\Omega_{c}^{(*)}. Using these we give predictions for the Cabibbo-allowed
nonleptonic decay widths and up-down asymmetries for \Omega_{b} \to
\Omega_{c}^{(*)} plus a pseudoscalar or vector meson.


title:
Direct CP Violation in \Lambda_b -> n (\Lambda)\pi^+\pi^- Decays via
  \rho-\omega Mixing

abstract:
  We study direct CP violation in the bottom baryon decays \Lambda_b -> f
\rho^0 (\omega) -> f\pi^+\pi^- (f=n or \Lambda). It is found that in these
decays via \rho-\omega mixing the CP violation could be very large when the
invariant mass of the \pi^+\pi^- pair is in the vicinity of the \omega
resonance. With a typical value N_c =2 in the factorization approach, the
maximum CP-violating asymmetries are more than 50% and 68% for \Lambda_b -> n
\pi^+\pi^- and \Lambda_b -> \Lambda \pi^+\pi^-, respectively. With the aid of
heavy quark symmetry and phenomenological models for the hadronic wave
functions of \Lambda_b, \Lambda and the neutron, we estimate the branching
ratios of \Lambda_b -> n (\Lambda)\rho^0.


title:
Probability Distribution Function of the Coarse-grained Scalar Field at
  Finite Temperature

abstract:
  We present a formalism to calculate the probability distribution function of
a scalar field coarse-grained over some spatial scales with a Gaussian filter
at finite temperature. As an application, we investigate the role of
subcritical fluctuations in the electroweak phase transition in the minimal
standard model. It is concluded that the universe was in a mixed state of true
and false vacua already at the critical temperature.


title:
KK bar scattering amplitude to one loop in chiral perturbation theory,
  its unitarization and pion form factors

abstract:
  We have calculated the KK bar --> KK bar scattering amplitude to next to
leading order in Chiral Perturbation Theory. Then, making use of a
unitarization procedure with one or several coupled channels (\pi\pi, KK bar in
our case) we have calculated the \pi\pi --> \pi\pi, \pi\pi --> KK bar and KK
bar --> KK bar S and P waves in good agreement with the experiment up to
\sqrt{s}= 1.2 GeV. The \pi\pi scattering lengths with isospin and spin (I,J)
equal to (0,0), (1,1) and (2,0) are also calculated in agreement with
experiment and former Chiral Perturbation Theory calculations. Finally we have
employed these amplitudes, making use of an Omnes representation, to calculate
the scalar and the vector pion form factors, obtaining a good agreement with
the available experimental data.


title:
Determining the Strange Quark Mass in Cabibbo Suppressed Tau Lepton
  Decays

abstract:
  In this work radiative corrections in the total hadronic decay rate of the
tau-lepton and some moments of its differential distributions are studied
employing perturbative QCD and the operator product expansion. We calculate
quadratic quark mass corrections in the strange mass to the decay rate ratio
R_tau to the order O(\alpha_s^3 m^2) and find that they contribute appreciably
to the Cabibbo suppressed decay modes of the tau-lepton. Using the results of a
recent experimental analysis, we obtain m_s(1 GeV) = 200 \pm 40_exp \pm 30_th
MeV.


title:
Constraints on Supersymmetric SO(10) GUTs with Sum Rules among Soft
  Masses

abstract:
  We study phenomenological aspects of supersymmetric SO(10) GUTs with sum
rules among soft SUSY breaking parameters. In particular, the sum rule related
to the stau mass leads to the constraints from the requirements of successful
electroweak breaking and the positivity of stau mass squared. The bottom quark
mass is also estimated.


title: Perturbative approach to the penguin-induced $B \to \pi \phi$

abstract:
  Using a modified perturbative approach that includes the Sudakov resummation
and transverse degrees of freedom we analyze the penguin-induced $B^{-} \to
\pi^{-}\phi$ decay by applying the next-to-leading order effective weak
Hamiltonian. The modified perturbative method enables us to include
nonfactorizable contributions and to control virtual momenta appearing in the
process. Besides, we apply the three-scale factorization theorem for
nonleptonic processes that offers the possibility of having the
scale-independent product of short- and long-distance parts in the amplitude of
the weak Hamiltonian. The calculation supports the results obtained in the BSW
factorization approach, illustrating the electroweak penguin dominance and the
branching ratio of order ${\cal O}(10^{-8})$. However, the estimated prediction
of 16% for the CP asymmetry is much larger than that obtained in the
factorization approach.


title: Hard exclusive $J/\psi$ leptoproduction on polarized targets

abstract:
  We consider the exclusive production of $J/\psi$ mesons in polarized
virtual-photon--proton collisions. We derive helicity amplitudes for the
dominant subprocess $\gamma^* g \to J/\psi g$ and show that polarization
asymmetries vanish in the case of collinear scattering. Thus, contrary to what
has been suggested earlier, this process is not a good probe of the polarized
gluon distribution $\Delta g(x,Q^2)$ of the proton.


title:
Bounds on scalar leptoquark masses from S, T, U parameters in the
  minimal four-color quark-lepton symmetry model

abstract:
  The contributions into radiative correction parameters S, T, U from the
scalar leptoquarks are calculated in the minimal gauge model with the
four-color quark-lepton symmetry. It is shown that the contributions into T and
U from the scalar leptoquark doublets are not positive definite. Using the
current experimental data on S, T, U the bounds on the scalar leptoquark masses
are obtained. In particular, the existence of the relatively light scalar
leptoquark with electric charge 2/3 is shown to be compatible with the current
experimental data on S, T, U.


title: Casimir corrections in the bound state soliton model

abstract:
  We consider the one-loop corrections to the SU(3) skyrmion mass within the
bound state soliton approach. We show that the standard SU(3) renormalization
scheme is not appropiate within this framework and propose to use an
alternative one based on SU(2). For physical meson masses and decay constants
the resulting Casimir correction turns out to be rather scale-independent and
leads to an acceptable estimate of the nucleon mass.


title:
Higgs Boson Discovery Potential of LHC in the Channel $pp
  \to\gamma\gamma+jet$

abstract:
  We discuss the SM Higgs discovery potential of LHC in the reaction $pp\to H+
jet\to\gamma\gamma+jet$ when the jet is observed at sufficiently high $E_t$ to
be reliably identified. We conclude that this channel gives promising discovery
possibilities for the Higgs boson mass range 100-140 GeV, during LHC operation
at a low luminosity. With 30 fb$^{-1}$ of accumulated data and for $M_H=120$
GeV about 100 signal events could be observed with the number of background
events larger by a factor of 2 only, showing a signal significance
$S/\sqrt{B}\sim 7$. We use the difference of distributions in the partonic
subprocess energy $\sqrt{\hat s}$ for the signal and background for a better
separation of the signal.


title: Double distributions and evolution equations

abstract:
  Applications of perturbative QCD to deeply virtual Compton scattering and
hard exclusive meson electroproduction processes require a generalization of
usual parton distributions for the case when long-distance information is
accumulated in nonforward matrix elements < p'| O(0,z) | p > of quark and gluon
light-cone operators. In our previous papers we used two types of
nonperturbative functions parametrizing such matrix elements: double
distributions F(x,y;t) and nonforward distribution functions F_\zeta(X;t). Here
we discuss in more detail the double distributions (DD's) and evolution
equations which they satisfy. We propose simple models for F(x,y;t=0) DD's with
correct spectral and symmetry properties which also satisfy the reduction
relations connecting them to the usual parton densities f(x). In this way, we
obtain self-consistent models for the \zeta-dependence of nonforward
distributions. We show that, for small \zeta, one can easily obtain nonforward
distributions (in the X > \zeta region) from the parton densities: F_\zeta
(X;t=0) \approx f(X-\zeta/2).


title:
Up-Down Asymmetry of Neutral Current Events as a Diagnostic for Nu_mu -
  Nu-st Versus Nu_mu- Nu_tau Oscillations

abstract:
  We show that the asymmetry in the neutral current events (e.g. Nu N -> Nu N
pi^0) can be used to discriminate between Nu_mu - Nu_tau and Nu_mu - Nu_st
mixing as being responsible for the atmospheric neutrino anomaly. Specifically,
A_N vanishes for Nu_mu - Nu_tau mixing and is about 2/3 A_mu for Nu_mu - Nu_st
mixing.


title:
Next-to-next-to-leading order relation between $R(e^+e^-\to b\bar b)$
  and $\Gamma_{\rm sl}(b\to cl\nu_l)$ and precise determination of $|V_{cb}|$

abstract:
  We present the next-to-next-to-leading order relation between the moments of
the $\Upsilon$ system spectral density and the inclusive $B$-meson semileptonic
width. The perturbative series for the width as an explicit function of the
moments is well convergent in three consequent orders in the strong coupling
constant that provides solid and accurate theoretical estimate. As a result,
the uncertainty of the value of $|V_{cb}|$ Cabibbo-Kobayashi-Maskawa matrix
element is reduced.


title: Baryons in a chiral constituent quark model

abstract:
  In the low-energy regime light and strange baryons should be considered as
systems of constituent quarks with confining interaction and a chiral
interaction that is mediated by Goldstone bosons as well as by vector and
scalar mesons. The flavor-spin structure and sign of the short-range part of
the spin-spin force reduces the $SU(6)_{FS}$ symmetry down to $SU(3)_F \times
SU(2)_S$, induces hyperfine splittings and provides correct ordering of the
lowest states with positive and negative parity. There is a cancellation of the
tensor force from pseudoscalar- and vector-exchanges in baryons. The spin-orbit
interactions from $\rho$-like and $\omega$-like exchanges also cancel each
other in baryons while they produce a big spin-orbit force in NN system. A
unified description of light and strange baryon spectra calculated in a
semirelativistic framework is presented. It is demonstrated that the same
short-range part of spin-spin interaction between the constituent quarks
induces a strong short-range repulsion in $NN$ system when the latter is
treated as $6Q$ system. Thus one can achieve a simultaneous understanding of a
baryon structure and baryon-baryon interaction in the low-energy regime.


title: Superheavy Dark Matter with Discrete Gauge Symmetries

abstract:
  We show that there are discrete gauge symmetries protect naturally heavy X
particles from decaying into the ordinary light particles in the supersymmetric
standard model. This makes the proposal very attractive that the superheavy X
particles constitute a part of the dark matter in the present universe. It is
more interesting that there are a class of discrete gauge symmetries which
naturally accommodate a long-lived unstable X particle. We find that in some
discrete Z_{10} models, for example, a superheavy X particle has lifetime
\tau_X \simeq 10^{11}-10^{26} years for its mass M_X \simeq 10^{13}-10^{14}
GeV. This long lifetime is guaranteed by the absence of lower dimensional
operators (of light particles) couple to the X. We briefly discuss a possible
explanation for the recently observed ultra-high-energy cosmic ray events by
the decay of this unstable X particle.


title:
On the D^*+_s -> D^+_s pi^0 decay in the Effective quark model with
  chiral U(3)xU(3) symmetry

abstract:
  The partial width of the decay D^*+_s -> D^+_s pi^0 going through the
violation of isotopical symmetry is computed with respect to the partial width
of the radiative decay D^*+_s -> D^+_s gamma in the effective quark model with
chiral U(3)xU(3) symmetry incorporating Heavy quark effective theory (HQET) and
Chiral perturbation theory at the quark level (CHPT)_q. We investigate a
sensitivity of the ratio of the partial widths R_0 to current s-quark mass
corrections and find a strong dependence.


title:
Effective quark model with chiral U(3)XU(3) symmetry for baryon octet
  and decuplet

abstract:
  We suggest an effective quark model for low-lying baryon octet and decuplet
motivated by QCD with a linearly rising confinement potential incorporating the
extended Nambu-Jona-Lasinio (ENJL) model with linear realization of chiral
U(3)XU(3) symmetry. Baryons are considered as external heavy states coupled to
local three-quark currents with fixed spinorial structure and to low-lying
mesons through quark-meson interactions defined in the ENJL--model. In the
constituent quark loop representation we have calculated the coupling constants
of the (pi NN), (pi N Delta) and (gamma N Delta) interactions and the
(sigma_{\pi N})-term. The obtained results are in reasonable agreement with
experimental data and other effective field theory approaches.


title:
The Higgs Boson Mass as a Probe of the Minimal Supersymmetric Standard
  Model

abstract:
  Recently, the LEP collaborations have reported a lower bound on a Standard
Model-like Higgs boson of order 89 GeV. We discuss the implications of this
bound for the minimal supersymmetric extension of the Standard Model (MSSM). In
particular, we show that the lower bound on $\tan\beta$, which can be obtained
from the presently allowed Higgs boson mass value, becomes stronger than the
one set by the requirement of perturbative consistency of the theory up to
scales of order $M_{GUT}$ (associated with the infrared fixed-point solution of
the top quark Yukawa coupling) in a large fraction of the allowed parameter
space. The potentiality of future LEP2 searches to further probe the MSSM
parameter space is also discussed.


title: Fracture functions: factorization and evolution

abstract:
  Fracture functions and their evolution equations are reviewed. Some
phenomenological applications are briefly discussed.


title: Tensor susceptibilities of the vacuum from constituent quarks

abstract:
  We show that the constituent quark model leads to simple expressions for the
isoscalar and isovector tensor susceptibilities of the vacuum. The found values
are negative and of magnitude compatible with QCD-sum-rule parameterizations of
spectral densities in appropriate L=1-meson channels.


title: Do internal symmetries get restored in hot and dense SUSY?

abstract:
  I offer some computational details and useful and concise formulae to
calculate the effective potential for a general abelian supersymmetric model at
high temperature and density. It will be shown that such cases are very good
candidates for symmetry nonrestoration at high temperature, providing large
densities are present.


title: F_2 Structure Function and Higher-twist Contributons (Nonsinglet Case)

abstract:
  We performed the combine fits of SLAC, BCDMS and NMC data at NLO level. The
data are fitted very well with different parametrizations of higher twist
contributions. The theory-based parametrizations lead to the low values of QCD
parameter \Lambda^{f=4}_{\overfull{MS}} \sim 140 \pm 21 MeV (or
\alpha_s(M^2_Z)= 0.103 \pm 0.002).


title: Comment on the hadronic decay of excited heavy quarkonia

abstract:
  We make comments on ref.[Z.Phys. C73, 541 (1997)], and provide partial wave
analysis to the decays of excited heavy S-wave $1^-$ quarkonia into the basic
$1^-$ quarkonia state plus $\pi\pi$. It is revealed that there exist
contributions of D-wave transition in $\psi'\longrightarrow J/\psi\pi\pi$,
$\Upsilon(2S)\longrightarrow \Upsilon(1S) \pi \pi$ and
$\Upsilon(3S)\longrightarrow \Upsilon(1S) \pi \pi$ by using the data-fitting
results in ref.[Z.Phys C73, 541 (1997)]. A possible experimental method to
measure the D-wave directly is discussed.


title: Off-shell W pair production with anomalous couplings: The CC11 process

abstract:
  The differential cross-sections for processes of the type e+ e- to W+ W- to l
nu q anti-q are determined with account of background contributions and of
anomalous triple gauge boson couplings. Analytic expressions for dsigma/ds1 ds2
dcostheta, where theta is the production angle of the W boson, are numerically
integrated with the Fortran package GENTLE. QED corrections are taken into
account in the leading logarithmic approximation. The importance of the various
contributions is studied for center-of-mass energies of 190 GeV, 500 GeV, and 1
TeV.


title: (Pi+Pi-) Atom in Chiral Perturbation Theory

abstract:
  Hadronic (Pi+Pi-) atom is studied in the relativistic perturbative approach
based on the Bethe-Salpeter equation. The general expression for the atom
lifetime is derived. Lowest-order corrections to the relativistic Deser-type
formula for the atom lifetime are evaluated within the Chiral Perturbation
Theory.


title: Non-Relativistic Pion Interactions and the Pionium Lifetime

abstract:
  We construct an effective Lagrangian for interacting pions with
non-relativistic energies. The coupling constants can be expressed in terms of
the different scattering lengths and slopes. When used in the calculation of
the pionium decay rate, the scattering slope contribution gives a correction of
about 8% compared with the lowest order contribution coming from the scattering
lengths alone.


title: CP Violation in Top Quark Pair Production at Hadron Colliders

abstract:
  CP violating effects in top quark pair production at the future 2 TeV $p\bar
p$ Tevatron and 14 TeV $pp$ LHC colliders are investigated. We study three
kinds of CP violating sources:the supersymmetric CP-odd phase of the stop
trilinear soft breaking term: $arg(A_t)$, the CP-odd parameter in two-Higgs
doublet extensions of the standard model(2HDM), and the model-independent top
quark chromoelectric dipole moment(CEDM), respectively. Optimal observables as
well as simple observables are used. We find that it is possible to observe CP
violating effects from $arg(A_t)$ in top quark pair production at the 2 TeV
Tevatron with $\sim 30fb^{-1}$ integrated luminosity when $m_{\tilde{g}}\sim
200$ GeV. If the experimental systematic errors are sufficient small, the LHC
with $\sim 150fb^{-1}$ can put a limit of order $10^{-1}$ on the phase
$arg(A_t)$ and the CP-odd parameter in 2HDM by using optimal observables. The
CEDM of the top quark can be measured to an accuracy of $10^{-18} cm g_s$ at
the Tevatron and few $\times 10^{-20} cm g_s$ at the LHC.


title: QCD description of high order factorial moments in quark and gluon jets

abstract:
  The complete QCD evolution equation for factorial moments in quark and gluon
jets is numerically solved with initial conditions at threshold by fully taking
into account the energy-momentum conservation law. Within the picture of Local
Parton Hadron Duality, the perturbative QCD predictions can successfully
describe the available experimental data.


title:
Time evolution of correlation functions for classical and quantum
  anharmonic oscillators

abstract:
  The time evolution of the correlation functions of an ensemble of anharmonic
N-component oscillators with O(N) symmetry is described by a flow equation,
exact up to corrections of order $1/N^2$. We find effective irreversibility.
Nevertheless, analytical and numerical investigation reveals that the system
does not reach thermal equilibrium for large times, even when $N\to \infty$.
Depending on the initial distribution, the dynamics is asymptotically stable or
it exhibits growing modes which break the conditions for the validity of the
1/N expansion for large time. We investigate both classical and quantum
systems, the latter being the limit of an O(N) symmetric scalar quantum field
theory in zero spatial dimensions.

categories: hep-ph astro-ph cond-mat hep-th quant-ph


title: Rochelle salt: a prototype of particle physics

abstract:
  Rochelle salt has a remarkable characteristic of becoming more ordered for a
range of high temperatures before melting. In the particle physics language
this means more symmetry breaking for high T. In many realistic field theories
this is a perfectly consistent scenario which has profound consequences in the
early universe. In particular it implies that there may be no domain wall and
monopole problems, and it may also play an important role in baryogenesis if CP
and P are broken spontaneously. In the case of the monopole problem this may
require a large background charge of the universe. The natural candidates for
this background charge are a possible lepton number in the neutrino sea or
global continous R-charges in supersymmetric theories.


title:
On production $e^+ e^-$-pairs by a high energy photon in collision with
  photons of a laser wave

abstract:
  We calculate the number of $e^+ e^-$-pairs produced by a Compton high energy
photon in turn formed in the process $e + n \gamma_0 -> e + \gamma$ at
simultaneous collision with several photons $\gamma_0$ of the same laser beam
$\gamma + s \gamma_0 -> e^+ + e^-$. The case when polarization states of
initial electron beam and laser photons are helicity is considered. It is shown
that taking into account nonlinear effects in the Compton backscattering leads
to decreasing the threshold of production of $e^+ e^-$-pairs and increasing
their number. The consideration is based on the direct calculation of matrix
elements in the formalism of diagonal spin basis.


title: $\tau\to\rho\pi\pi\nu$ decays

abstract:
  Effective chiral theory of mesons is applied to study the four decay modes of
$\tau\to\rho\pi\pi\nu$. Theoretical values of the branching ratios are in
agreement with the data. The theory predicts that the $a_{1}$ resonance plays a
dominant role in these decays. There is no new parameter in this study.


title:
O(N_f alpha^2) Electromagnetic Charge Renormalization in the Standard
  Model

abstract:
  The O(N_f alpha^2) electroweak radiative corrections to the Thomson
scattering matrix element are calculated for a general renormalization scheme
with massless fermions. All integrals can be evaluated exactly in dimensional
regularization which in several cases yields new results that are remarkably
simple in form. A number of stringent internal consistency checks are
performed. The Z-gamma mixing complicates the calculation of 1-particle
reducible diagrams considerably at this order and a general treatment of this
problem is given. Conditions satisfied by O(N_f alpha^2) counterterms are
derived and may be applied to other calculations at this order.


title: Difficulties with Photonic Searches for Magnetic Monopoles

abstract:
  Recently, there have been proposals that the classic Euler-Heisenberg
Lagrangian together with duality could be employed to set limits on magnetic
monopoles having masses less than 1 TeV. The D0 collaboration at Fermilab has
used such a proposal to set mass limits based on the nonobservation of pairs of
photons each with high transverse momentum. In this note, we critique the
underlying theory, by showing that at the quoted limits the cross section
violates unitarity and is unstable with respect to radiative corrections. It is
proposed that the correct coupling of magnetic monopoles to photons leads to an
effective softening of the interaction, leading to a much smaller cross
section, from which no significant limit can be obtained from the current
experiments. Previous limits based on virtual monopole loops are similarly
criticized.


title: Effective operator contributions to the oblique parameters

abstract:
  We present a model and process independent study of the contributions from
non-Standard Model physics to the oblique parameters S, T and U. We show that
within an effective lagrangian parameterization the expressions for the oblique
parameters in terms of observables are consistent, while those in terms of the
vector-boson vacuum polarization tensors are ambiguous. We obtain the
constraints on the scale of new physics derived from current data on S, T and U
and note that deviations in U from its Standard Model value would favor a
scenario where the underlying physics does not decouple.


title:
Enhancement of \mu \to e \gamma in the supersymmetric SU(5) GUT at large
  \tan\beta

abstract:
  Branching ratio of $\mu \to \e \gamma$ is evaluated in the supersymmetric
SU(5) grand unified theory taking account of higher dimensional operators,
which reproduce the realistic quark and lepton masses and the mixing
parameters. It is shown by numerical calculation that at large $\tan\beta$ the
branching ratio is enhanced by a few orders of magnitude since the flavor
mixings for both the left- and the right-handed sleptons are induced by the
effect of the higher dimensional operators.


title: Neutrino Masses and Mixings in the Light of Experimental Data

abstract:
  All the possible schemes of neutrino mixing with four massive neutrinos
inspired by the existing experimental indications in favour of neutrino mixing
are considered. It is shown that the scheme with a neutrino mass hierarchy is
not compatible with the experimental results, likewise all other schemes with
the masses of three neutrinos close together and the fourth mass separated by a
gap needed to incorporate the LSND neutrino oscillations. Only two schemes with
two pairs of neutrinos with close masses separated by this gap of the order of
1 eV are in agreement with the results of all experiments. We carefully examine
the arguments leading to this conclusion and also discuss experimental
consequences of the two favoured neutrino schemes.


title: Low $x$ physics and Structure Functions

abstract:
  In this talk I review the behaviour of structure functions at low values of
Bjorken $x$ and discuss the theoretical underpinnings with particular attention
to resummation schemes. I present the need for 'less inclusive' events to
distinguish between various resummation schemes and discuss the various
difficulties in differentiating experimentally between different schemes.


title: Sudakov Resummation for Electroproduction of Heavy Quarks

abstract:
  The leading and next-to-leading threshold logarithms of the QCD corrections
to electroproduction of heavy quarks in single-particle inclusive kinematics
are resummed to all orders in perturbation theory. The resummed cross-section
is used to derive the NLO and NNLO results near threshold and their numerical
impact on the charm structure function is studied.


title:
Inquiry for the \pi^+ \pi^- bound state conversion in two \pi^0 as being
  due to the Weinberg pion-pion-interaction lagrangian

abstract:
  In the work presented, the decay of the pionium, that is the \pi^+ \pi^-
bound state, into two \pi^0 is studied, the \pi\pi-interaction causing this
transition being described by the underlying Weinberg lagrangian. The
calculation with such a \pi\pi-lagrangian being carried out, the \pi-meson size
r_{0}-emerges to be allowed for and occurs in the final result. The bound
\pi^+\pi^- system itself is presumed to be due to the instantaneous Coulomb
interaction and is treated consistently nonrelativistic, the Bethe-Solpeter
equation being utilized. Along calculating, the terms of the lowest order in
fine structure constant \alpha and the terms \sim \ln(r_{0}) are retained. The
obtained pionium lifetime \tau is thought to be compatible with the conceivable
future experimental data. The dependence of the results on the effective
lagrangian parameters is visualized. The investigation carried out persuades us
that just the whole form of the genuine \pi-interaction determines the pionium
lifetime, but not simply the \pi\pi scattering lengths. The inquiry into
pionium decaying promotes to specify the validity of various \pi\pi-interaction
descriptions.


title: Supersymmetric Electroweak Corrections to Top Quark Production at LHC

abstract:
  The $\alpha m_t^2/m_W^2$ order supersymmetric electroweak corrections arising
from loops of chargino, neutralino, and squark to top quark pair production by
$gg$ fusion at LHC are calculated in the minimal supersymmetric model. We found
that the corrections amount about a few percent.


title:
Higgs Scalar-Pseudoscalar Mixing in the Minimal Supersymmetric Standard
  Model

abstract:
  In the minimal supersymmetric Standard Model, the heaviest CP-even Higgs
boson H and the CP-odd Higgs scalar A are predicted to be almost degenerate in
mass at the tree level, for the wide kinematic range M_A > 2M_Z and \tan\beta
\ge 2. However, if large soft-CP-violating Yukawa interactions involving scalar
quarks of the third generation are present in the theory, then the CP
invariance of the Higgs potential can be maximally broken beyond the Born
approximation, and the high degree of mass degeneracy between H and A may be
lifted through a sizeable HA mixing. After taking the CP-odd tadpole
renormalization of the A boson into account, we find that the small mass
difference M_H - M_A, which is about 1% of the A-boson mass at the tree level,
can be substantially enhanced to the 25% level at the one-loop order. We also
find that the loop-induced mixing between the lightest CP-even Higgs boson h
and the A boson may be of comparable size to M_h. We briefly discuss the main
phenomenological implications of the predicted hA and HA mixings for the
general Higgs-boson mass spectrum and for CP-violating observables at collider
and lower energies.


title: About Q2 Dependence of the Measured Asymmetry A_1(x)

abstract:
  We propose the new approach for taking into account the Q2 dependence of
measured asymmetry A_1. This approach is based on the similarity of the Q2
behaviour and the shape of the spin-dependent structure function g_1(x,Q^2) and
spin averaged structure function F_3(x,Q^2). The analysis is applied on the SMC
and E154 experimental data.


title:
Production of bound {$\mu^{+}\mu^{-}$}-systems in relativistic heavy ion
  collisions

abstract:
  Dimuonium (the bound system of two muons, $\mu^+\mu^-$-atom) has not been
observed yet. In this paper we discuss the electromagnetic production of
dimuonium at RHIC and LHC in relativistic heavy ion collisions. The production
of parastates is analyzed in the equivalent photon approximation. For the
treatment of orthostates, we develop a three photon formalism. We determine the
production rates at RHIC and LHC with an accuracy of a few percent and discuss
problems related to the observation of dimuonium.


title:
The Anomalous Magnetic Moment of the Muon and Higgs-Mediated Flavor
  Changing Neutral Currents

abstract:
  In the two-Higgs doublet extension of the standard model, flavor-changing
neutral couplings arise naturally. In the lepton sector, the largest such
coupling is expected to be $\mu-\tau-\phi#. We consider the effects of this
coupling on the anomalous magnetic moment of the muon. The resulting bound on
the coupling, unlike previous bounds, is independent of the value of other
unknown couplings. It will be significantly improved by the upcoming E821
experiment at Brookhaven National Lab.


title: Five-Dimensional Aspects of M-Theory Dynamics and Supersymmetry Breaking

abstract:
  We discuss the reduction of the eleven-dimensional M-theory effective
Lagrangian, considering first compactification from eleven to five dimensions
on a Calabi-Yau manifold, followed by reduction to four dimensions on an
S_1/Z_2 line segment at a larger distance scale. The Calabi-Yau geometry leads
to a structure of the five-dimensional Lagrangian that has more freedom than
the eleven-dimensional theory. In five dimensions one obtains a non-linear
sigma-model coupled to gravity, which implies non-trivial dynamics for the
scalar moduli fields in the bulk of the Z_2 orbifold. We discuss solutions to
the five-dimensional equations of motion in the presence of sources localized
on the boundaries of the Z_2 orbifold that may trigger supersymmetry breaking,
e.g., gaugino condensates. The transmission of supersymmetry breaking from the
hidden wall to the visible wall is demonstrated in specific models. The role of
the messenger of supersymmetry breaking may be played by the gravity
supermultiplet and/or by scalar hypermultiplets. The latter include the
universal hypermultiplet associated with the Calabi-Yau volume, and also the
hypermultiplets associated with deformations of its complex structure, which
mix in general.


title: Higgs Limit and b->s gamma Constraints in Minimal Supersymmetry

abstract:
  New limits on the Higgs mass from LEP and new calculations on the radiative
(penguin) decay of the b->s gamma branching ratio restrict the parameter space
of the Constrained Minimal Supersymmetric Standard Model (CMSSM).
  We find that for the low tan(beta) scenario only one sign of the Higgs mixing
parameter is allowed, while the high tan(beta scenario is practically excluded,
if one requires all sparticles to be below 1 TeV and imposes radiative
electroweak symmetry breaking as well as gauge and Yukawa coupling unification.
For squarks between 1 and 2 TeV high tan(beta) scenarios are allowed. We
consider especially a new high tan(beta)=64 scenario with triple unification of
all Yukawa couplings of the third generation, which show an infrared fixed
point behaviour.
  The upper limit on the mass of the lightest Higgs in the low (high) tan(beta)
scenarios is 97+-6~(120+-2) GeV, where the errors originate predominantly from
the uncertainty in the top mass.


title: A strongly-interacting phase of the Minimal Supersymmetric Model

abstract:
  We argue that in the minimal supersymmetric extension of the Standard Model
with a large trilinear coupling both the fundamental Higgs boson and a bound
state of squarks (formed via strong scalar interaction) can have a non-zero
VEV. This alters drastically the pattern of electroweak-symmetry breaking and
the Higgs phenomenology. In particular, the upper bound on the supersymmetric
Higgs-boson mass may be relaxed. Also, the Higgs boson can be produced at
hadron colliders through a direct coupling to gluons.


title: Probing partonic structure in gamma* gamma -> pi pi near threshold

abstract:
  Hadron pair production gamma* gamma -> h hbar in the region where the c.m.
energy is much smaller than the photon virtuality can be described in a
factorized form, as the convolution of a partonic handbag diagram and
generalized distribution amplitudes which are new non-perturbative functions
describing the exclusive fragmentation of a quark-antiquark pair into two
hadrons. Scaling behavior and a selection rule on photon helicity are
signatures of this mechanism. The case where h is a pion is emphasized.


title: Non-diagonal parton distribution functions

abstract:
  We explain why the time ordering in the definition of non-diagonal parton
distributions can be omitted and discuss the physics implications.


title: Pion Breather States in QCD

abstract:
  We describe a class of pionic breather solutions (PBS) which appear in the
chiral lagrangian description of low-energy QCD. These configurations are
long-lived, with lifetimes greater than $10^3$ fm/c, and could arise as
remnants of disoriented chiral condensate (DCC) formation at RHIC. We show that
the chiral lagrangian equations of motion for a uniformly isospin-polarized
domain reduce to those of the sine-gordon model. Consequently, our solutions
are directly related to the breather solutions of sine-gordon theory in 3+1
dimensions. We investigate the possibility of PBS formation from multiple
domains of DCC, and show that the probability of formation is non-negligible.


title: Three-Body Annihilation of Neutralinos Below Two-Body Thresholds

abstract:
  We calculate the cross section for s-wave neutralino annihilation to
three-body final states below the W^+ W^- and t-bar t thresholds. Such
three-body channels may dominate the annihilation cross section if the
neutralino mass is not too much less than m_t and m_W respectively.
Furthermore, because neutrinos produced in these channels are much more
energetic than those from the $b\bar{b}$ or tau^+ tau^- channels, they can
dominate the energetic-neutrino fluxes from neutralino annihilation in the Sun
or Earth far below these thresholds and significantly enhance the neutrino
signal in certain regions of the supersymmetric parameter space.


title: Tagged photons in DIS with next-to-leading accuracy

abstract:
  The leading and next-to-leading radiative corrections to deep inelastic
events with tagged photons are calculated analytically. Comparisons with
previous results and numerical estimations are presented for the experimental
conditions at HERA.


title:
One-particle and collective electron spectra in hot and dense QED and
  their gauge dependence

abstract:
  The one-particle electron spectrum is found for hot and dense QED and its
properties are investigated in comparison with the collective spectrum. It is
shown that the one-particle spectrum (in any case its zero momentum limit) is
gauge invariant, but the collective spectrum, being qualitatively different, is
always gauge dependent. The exception is the case $m,\mu=0$ for which the
collective spectrum long wavelength limit demonstrates the gauge invariance as
well.


title: Atmospheric neutrino oscillations in three-flavor neutrinos

abstract:
  We analyzed the atmospheric neutrino experiments of SuperKamiokande including
zenith angle dependence's using the three-flavor neutrino framework with the
hierarchy m^2_1 \approx m^2_2<<m^2_3. Taking into account the terrestrial,
solar neutrino experimental data and the atmospheric neutrino experiments
including the sub-GeV and multi-GeV data in SuperKamiokande, large angle
solution in the solar neutrino experiments is favored and the range of the mass
parameter Deltam^2_{23} is restricted between 0.08eV^2 - 2eV^2. Allowed regions
of mixing parameters are (theta_{13}<4degree, 27degree<theta_{23}< 32degree)
for Delta m_{23}^2=1eV^2 and (theta_{13}<3degree, 28degree<theta_{23}
<33degree) for Deltam_{23}^2=0.1 eV^2.


title: Four-neutrino mixing and long-baseline neutrino oscillation experiments

abstract:
  We consider the two schemes with four massive neutrinos which are compatible
with the results of all neutrino oscillation experiments. We show that in these
two schemes the probabilities of nu_e disappearance and nu_mu->nu_e appearance
in long-baseline experiments are strongly suppressed.


title: Inclusive direct CP-asymmetries in charmless B^{+/-}-decays

abstract:
  Direct CP-asymmetries in inclusive decay modes can be cleanly calculated by
exploiting quark-hadron duality. This is in sharp contrast to CP-asymmetries in
exclusive channels, where unknown strong phases prevent a clean extraction of
CKM parameters from measured CP-asymmetries. We have calculated the inclusive
CP-asymmetries in B^{+/-}-decays into charmless final states with strangeness
one or strangeness zero. In our results large logarithms are properly summed to
all orders. We find
  a_{CP} ( Delta S=0 ) = ( 2.0 +1.2 / -1.0) % and
  a_{CP} ( Delta S=1 ) = (-1.0 +/- 0.5 ) % .
  The constraints on the apex (rho-bar,eta-bar) of the unitarity triangle
obtained from these two CP-asymmetries define circles in the
(rho-bar,eta-bar)-plane. a_{CP} ( Delta S=0 ) measures sin(gamma) times
|V_{cb}/V_{ub}|. The presented work has been done in collaboration with Gaby
Ostermaier and Alexander Lenz.


title: The Vector and Scalar Form Factors of the Pion to Two Loops

abstract:
  We calculate the vector and scalar form factors of the pion to two loops in
Chiral Perturbation Theory. We estimate the unknown O(p^6) constants using
resonance exchange. We make a careful comparison to the available data and
determine two O(p^4) constants rather precisely, and two O(p^6) constants less
precisely. We also use Chiral Perturbation Theory to two loops to extract in a
model--independent manner the charge radius of the pion from the available
data, and obtain \rpiV=0.437\pm 0.016 fm^2.


title:
Differences Between the Pole and On-Shell Masses and Widths of the Higgs
  Boson

abstract:
  The differences between the on-shell mass and width of the Higgs boson and
their pole counterparts are evaluated in leading order. For a heavy Higgs
boson, they are found to be sensitive functions of the gauge parameter and
become numerically large over a class of gauges that includes the unitary
gauge. For a light Higgs boson, the differences remain small in all gauges. The
pinch-technique mass and width are found to be close to their pole counterparts
over a large range of Higgs boson masses.


title: Testing Quantum Mechanics in Nuetrino Oscillation

abstract:
  A testing of quantum mechanics in nuetrino oscillation is presented. The
quantum mechanics violation motivated by arguements of quantum gravity is
investigated in neutrino system. The formula of density matrix and oscillation
probability of nuetrinos with and without the effect of quantum mechanics
violation are derived for the cases of neutrino ocsillation in vacuum and
matter. The limits to the corresponding parameters are obtained from neutrino
experiments.


title: Power Corrections at LEP

abstract:
  The size of non-perturbative corrections to event shape observables is
predicted to fall like powers of the inverse centre of mass energy. These power
corrections are investigated for different observables from
$e^+e^-$-annihilation measured at LEP as well as previous experiments. The
obtained corrections are compared to other approaches and theoretical
predictions. Measurements of $\alpha_s$ using power corrections are compared to
conventional methods.


title: Baryons in a Covariant and Confining Diquark--Quark Model

abstract:
  In a covariant model where constituent quarks and diquarks interact through
quark exchange, the Bethe-Salpeter equation in ladder approximation for octet
and decuplet baryons is solved. Quark and diquark confinement is thereby
effectively parametrised by choosing appropriately modified propagators.
Numerical results for the baryon masses are presented. In a second step
electromagnetic, weak and pionic currents are coupled to the bound state
according to Mandelstam's technique. The arising matrix elements are evaluated
in a generalised impulse approximation and observable form factors are
extracted.


title: Odderon and QCD

abstract:
  A review is made of the odderon idea in high-energy physics, complemented by
an outline of the recent calculations of the odderon properties in the
perturbative QCD.


title:
Finiteness of Multi-body Neutrino Exchange Potential Energy in Neutron
  Stars

abstract:
  The multi-body neutrino potential energy is analytically estimated for a
spherical neutron star with a vector potential model for neutrinos. We show
that the self-energy and the neutrino number of the neutron star coincide with
the semi-classical values in the large volume limit, and confirm that there is
no catastrophe in neutron stars with massless neutrinos.


title: Resolved photon processes in DIS and small x dynamics

abstract:
  It has been found that recent results on forward jet production from deep
inelastic scattering can neither be reproduced by models which are based on
leading order alpha_s QCD matrix elements and parton showers nor by
next-to-leading order calculations. The measurement of forward jet cross
sections has been suggested as a promising probe of new small x dynamics and
the question is whether these data provide an indication of this. The same
question arises for other experimental data in deep inelastic scattering at
small x which can not be described by conventional models for deep inelastic
scattering. In this paper the influence of resolved photon processes has been
investigated and it has been studied to what extent such processes are able to
reproduce the data. It is shown that two DGLAP evolution chains from the hard
scattering process towards the proton and the photon, respectively, are
sufficient to describe effects, observed in the HERA data, which have been
attributed to BFKL dynamics.


title:
Relic Abundance of Neutralinos in Heterotic String Theory: Weak Coupling
  vs. Strong Coupling

abstract:
  The relic abundance of stable neutralinos is investigated in $E_8 \times
E_8'$ heterotic string theory when supersymmetry is spontaneously broken by
hidden-sector gaugino condensates. In the weak coupling regime, very large
scalar masses (compared to gaugino masses) are shown to lead to a too large
relic abundance of the neutralinos, incompatible with cosmological observations
in most of parameter space. The problem does not arise in the strong coupling
regime (heterotic M-theory) because there scalar and gaugino masses are
generically of the same order of magnitude.


title: Gravitational phase transition of heavy neutrino matter

abstract:
  In the framework of the Thomas-Fermi model at finite temperature, we show
that a cooling nondegenerate gas of massive neutrinos will undergo a phase
transition in which quasi-degenerate supermassive neutrino stars are formed
through gravitational collapse. For neutrinos in the mass range of 10 to 25 keV
these compact dark objects could mimic the role of supermassive black holes
that are usually assumed to exist at the centres galaxies. Astrophysical
implications and constraints on the neutrino mass are discussed for this
scenario.


title: Limits on the Mass of the Lightest SUSY Higgs

abstract:
  We study the limits on the mass of the lightest Higgs in supersymmetric
models extended with a gauge singlet when perturbative unification is required.
We find that when maximum intermediate matter is added, the different evolution
of the gauge couplings raises the mass bound from 135 GeV to 155 GeV. In these
models perturbative unification of the gauge couplings is achieved in a natural
way.


title: Stellar-Evolution Limits on Axion Properties

abstract:
  If axions exist, they are copiously produced in hot and dense plasmas,
carrying away energy directly from the interior of stars. Various astronomical
observables constrain the operation of such anomalous stellar energy-loss
channels and thus provide restrictive limits on the axion interactions with
photons, nucleons, and electrons. In typical axion models a limit m_a < 0.01 eV
is implied. The main arguments leading to this result are explained, including
more recent work on the important supernova 1987A constraint.


title: The Semileptonic Lifetime of the D Meson

abstract:
  The full treatment, both nonperturbative - through O(1/m_c^3) - and
perturbative - through O(alpha_s) and BLM type O(alpha_s^2) - of the
semileptonic lifetime of the D meson is given. A dedicated discussion of the
numerics involved is made, with the result that the leading order prediction
plus corrections fail to match experiment. To explain the difference, a model
of duality is invoked, where it is shown that the asymptotic nature of the
nonperturbative expansion may be responsible for the theoretical experimental
discrepancy. A particularly interesting conclusion which follows from the model
is that any attempts to extract alpha_s from tau decays are doomed, since the
same duality violating mechanism is at work here.


title: Bileptons from Muon Collider Backward Scattering

abstract:
  There are serious discussions for building a muon collider with
$\mu^{+}\mu^{-}$ collisions at c.o.m. energies up to 4 TeV. We point out that
the bileptonic gauge bosons predicted in some extensions of the Standard Model
would be readily discernable from the backward scattering cross-section, for
bilepton masses up to a substantial fraction of the c.o.m. energy.