title: Vacuum decay in quantum field theory

abstract:
  We study the contribution to vacuum decay in field theory due to the
interaction between the long and short-wavelength modes of the field. The field
model considered consists of a scalar field of mass $M$ with a cubic term in
the potential. The dynamics of the long-wavelength modes becomes diffusive in
this interaction. The diffusive behaviour is described by the reduced Wigner
function that characterizes the state of the long-wavelength modes. This
function is obtained from the whole Wigner function by integration of the
degrees of freedom of the short-wavelength modes. The dynamical equation for
the reduced Wigner function becomes a kind of Fokker-Planck equation which is
solved with suitable boundary conditions enforcing an initial metastable vacuum
state trapped in the potential well. As a result a finite activation rate is
found, even at zero temperature, for the formation of true vacuum bubbles of
size $M^{-1}$. This effect makes a substantial contribution to the total decay
rate.


title: T-odd fragmentation functions

abstract:
  We discuss the properties of fragmentation functions arising from the
interference of two leading hadrons produced inside the same jet in the current
fragmentation region of a hard process. For the case of semi-inclusive Deep
Inelastic Scattering (DIS), a proper folding of the cross section, integrated
over the azimuthal position of the detected hadrons, produces a factorized form
that allows for the extraction of the quark transversity distribution at
leading twist. Using an extended spectator model, explicit calculations are
shown for the hadron pair being two pions with invariant mass inside the $\rho$
resonance width.


title: CP Violation in a Supersymmetric SO(10) x U(2)_{F} Model

abstract:
  A model based on SUSY SO(10) combined with U(2) family symmetry constructed
recently by the authors is generalized to include phases in the mass matrices
leading to CP violation. In contrast with the commonly used effective operator
approach, $\bar{126}$-dimensional Higgs fields are utilized to construct the
Yukawa sector. R-parity symmetry is thus preserved at low energies. The
symmetric mass textures arising from the left-right symmetry breaking chain of
SO(10) give rise to very good predictions for quark and lepton masses and
mixings. The prediction for $\sin 2\beta$ agrees with the average of current
bounds from BaBar and Belle. In the neutrino sector, our predictions are in
good agreement with results from atmospheric neutrino experiments. Our model
favors both the LOW and QVO solutions to the solar neutrino anomaly; the matrix
element for neutrinoless double beta decay is highly suppressed. The leptonic
analog of the Jarlskog invariant, $J_{CP}^{l}$, is predicted to be of
$O(10^{-2})$.


title:
Novel Approach to Renormalize the Electroweak Sector of the Standard
  Model

abstract:
  We discuss a novel approach to renormalize the Electroweak Sector of the
Standard Model, in which \sin^2\theta_{eff}, measured at the Z^0 peak, is
identified with the basic renormalized electroweak mixing parameter. This
approach shares the desirable convergence properties of the MS scheme and
provides a framework for calculations that are strictly independent of the
electroweak scale in finite orders of perturbation theory. We illustrate the
method with updated precise calculations of \sin^2\theta_{eff} and M_W, as
functions of M_H, and comment on the implications of these calculations for the
Higgs boson search and the theoretical prediction of M_W.


title: Resummation of QCD Corrections to the eta_c Decay Rate

abstract:
  We examine the ratio of the decay rate of the eta_c into light hadrons to the
decay rate into photons and find that most of the large next-to-leading-order
(NLO) correction is associated with running of the strong coupling alpha_s. We
resum such contributions by analyzing final-state chains of vacuum-polarization
bubbles. We show that the nonperturbative parts of the bubble chains can be
absorbed into a color-octet matrix element, once one has used contour
deformations of the phase-space integrals to cancel certain contributions. We
argue that these contributions are incompatible with the uncertainty principle.
We also argue that perturbation theory is reliable only if one carries out the
phase-space integrations before the perturbation summation. Our results are in
good agreement with experiment and differ considerably from those that one
obtains by applying the scale-setting method of Brodsky, Lepage, and Mackenzie
to the NLO result.


title:
Model-Independent Predictions for Low Energy Isoscalar Heavy Baryon
  Observables in the Combined Heavy Quark and Large $N_c$ Expansion

abstract:
  Model-independent predictions for excitation energies, semileptonic form
factors and electromagnetic decay rates of isoscalar heavy baryons and their
low energy excited states are discussed in terms of the combined heavy quark
and large $N_c$ expansion. At leading order, the observables are completely
determined in terms of the known excitation energy of the first excited state
of $\Lambda_c$. At next-to-leading order in the combined expansion all heavy
baryon observables can be expressed in a model-independent way in terms of two
experimentally measurable quantities. We list predictions at leading and
next-to-leading order.


title: Unification without Unification

abstract:
  The logarithmic running of the gauge couplings alpha_1, alpha_2 and alpha_3,
indicates that they may unify at some scale M_GUT ~ 10^16. This is often taken
to imply that the standard model gauge group is embedded into some larger
simple group in which quarks and leptons are placed in the same multiplet.
These models have generic features, such as proton decay, and generic problems,
namely the splitting of the Higgs doublet and triplet. Inspired by the recent
discusion of dimensional deconstruction, we propose an interesting alternative:
we postulate a strongly coupled SU(3)xSU(2)xU(1), which is not the remnant of a
GUT, and is Higgsed with a weakly coupled SU(3)xSU(2)xU(1), which is the
remnant of a GUT, or with a GUT group directly, into the diagonal subgroup. In
this ``collapsed GUT'' mechanism, unification of coupling constants in the low
energy theory is expected, but proton decay and the doublet/triplet splitting
problem are entirely absent.


title: Deconstructing Gaugino Mediation

abstract:
  We present a model of supersymmetry breaking which produces gaugino masses
and negligible scalar masses at a high scale. The model is inspired by
``deconstructing'' or ``latticizing'' models in extra dimensions where
supersymmetry breaking and visible matter are spatially separated. We find a
simple four-dimensional model which only requires two lattice sites (or gauge
groups) to reproduce the phenomenology.


title: Photon-Reggeon Interaction Vertices in the Nla

abstract:
  We calculate the effective vertices for the quark-antiquark and the
quark-antiquark-gluon production in the virtual photon - Reggeized gluon
interaction. The last vertex is considered at the Born level; for the first one
the one-loop corrections are obtained. These vertices have a number of
applications; in particular, they are necessary for calculation of the virtual
photon impact factor in the next-to-leading logarithmic approximation.


title:
A Statistical Treatment to the Evolution Equation for Quark
  Distributions

abstract:
  The evolution of polarized quark distribution functions is taken into account
the gluon emission and absorption, quark pair production and annihilation
processes and treated by a statistical method which provides quark distribution
functions at small $Q^2$. The evolution function of quark distributions is
derived and solved by numerical methods. Then the $Q^2$ dependent and
$\alpha_{s}$ dependent structure functions $F_{2}(x, Q^{2})$ are obtained and
the example of it, the proton structure function, is calculated, whose increase
and decrease tendency with $\alpha_{s}$ at different $x$ is consistent with
experiments. This is also an evidence that the statistical methods for the
nucleon is reasonable.


title:
Neutrino Oscillations in Moving and Polarized Matter under the Influence
  of Electromagnetic Fields

abstract:
  Within the recently proposed \cite{ELSt99, ELStpl00, ELSt00} Lorentz
invariant formalism for description of neutrino spin evolution in presence of
an arbitrary electromagnetic fields matter motion and polarization effects are
considered. It is shown that in the case of matter moving with relativistic
speed parallel to neutrino propagation, matter effects in neutrino spin (and
also flavour) oscillations are suppressed. In the case of relativistic motion
of matter in the opposite direction in respect to neutrino propagation,
sufficient increase of effects of matter in neutrino oscillations is predicted.
These phenomena could have important consequences in different astrophysical
environments.


title: Probing Micro-quasars with TeV Neutrinos

abstract:
  The jets associated with Galactic micro-quasars are believed to be ejected by
accreting stellar mass black-holes or neutron stars. We show that if the energy
content of the jets in the transient sources is dominated by electron-proton
plasma, then a several hour outburst of 1--100 TeV neutrinos produced by photo-
meson interactions should precede the radio flares associated with major
ejection events. Several neutrinos may be detected during a single outburst by
a 1km^2 detector, thereby providing a powerful probe of micro-quasars jet
physics.


title:
Loop induced $W^{\pm}H^{\mp}$ associated production via photon-photon
  collisions in the THDM and the MSSM

abstract:
  We study the loop induced production of charged Higgs boson associated with
W-boson via photon-photon collisions at linear colliders (LC). The
investigation is carried out under the two-Higgs-doublet model(THDM) and the
minimal supersymmetric model (MSSM) using full on-mass-shell renormalization
scheme. The numerical analysis of their production rates is presented with some
typical parameter sets. The results show that the total cross sections in frame
of the MSSM at linear colliders(LC) can reach 0.1 femto barn quantitatively.
The contributions from supersymmetric sector can lead to an order of magnitude
enhancement of the cross section in some parameter space. We conclude that the
associated $W^{\pm}H^{\mp}$ production rate in photon-photon collision mode is
comparable to that in $e^+e^-$ collision mode.


title: What is the (epsilon'/epsilon)_exp Telling Us ?

abstract:
  Nature might be kinder than previously thought as far as epsilon'/epsilon is
concerned. We show that the recently obtained experimental value for
epsilon'/epsilon does not require sizeable 1/N and isospin-breaking
corrections. We propose to display the theoretical results for epsilon'/epsilon
in a (P^{1/2}, P^{3/2}) plane in which the experimental result is represented
by a (epsilon'/epsilon)_exp-path. This should allow to exhibit transparently
the role of 1/N and isospin-breaking corrections in different calculations of
epsilon'/epsilon. From now on theorists are allowed to walk only along this
(epsilon'/epsilon)_exp-path.


title:
Tests of SU(3) Symmetry-Breaking for Baryonic Beta Transitions in the
  Standard Model

abstract:
  It is generally assumed that deviations from flavor SU(3) symmetry arise
entirely from quark mass-differences, reflected in the mass splittings between
strange and nonstrange members of the same SU(3) multiplet. Under this
assumption, a parametrization is proposed which expresses the ratios of
Gamow-Teller to Fermi matrix elements for nucleon and hyperon beta decays
entirely in terms of two SU(3)-invariant coupling constants $F$ and $D$ and two
parameters $\gamma$ and $\delta$ representing SU(3) breaking effects.
Therefore, in principle, measurement of this ratio for any four
beta-transitions should yield all four parameters. Available data do not show
any evidence for SU(3) breaking. Improved measurements, also for transitions
not previously measured, would provide more stringent tests.


title:
Is there the color-flavor locking in the instanton induced
  quark-antiquark pairing in QCD vacuum?

abstract:
  By means of the functional integral method we show that in the case of the
quark-antiquark pairing at zero temperature and zero chemical potential (in the
vacuum) the singlet pairing is more preferable than that with the color-flavor
locking (CFL)


title: Model for Small neutrino masses at the TeV Scale

abstract:
  We propose a model for neutrino mass generation in wich no physics beyond a
TeV is required. We extend the standard model by adding two charged singlet
fields with lepton number two. Dirac neutrino masses $m_{\nu_D} \leq MeV$ are
generated at the one loop level. Small left handed majorana neutrino masses can
be generated via the seesaw mechanism with right handed neutrino masses $M_R$
are of order TeV scale.


title:
Large Isospin mixing in phi radiative decay and the spatial size of the
  f0(980)- a0(980) meson

abstract:
  The measured rate for phi to gamma f0(980) appears to be larger than allowed
on rather general grounds. We show that mixing between the f0(980) and a0(980),
due to their dynamical interaction with the nearby KKbar thresholds, radically
affects some existing predictions of their production in phi radiative decay.
We predict that Gamma(phi to gamma f0)/Gamma(phi to gamma a_0) approx 3; that
sum (b.r.(phi to gamma f0) + b.r. (phi to gamma a_0)) < 5 x 10^-4 with probable
individual branching ratios 2 x 10^-4 and 0.7 x 10^-4 respectively.


title:
Towards mapping the proton unintegrated gluon distribution in dijets
  correlations in real and virtual photoproduction at HERA

abstract:
  It is discussed how the dijet azimuthal correlations in DIS and real
photoproduction at HERA probe the unintegrated gluon distribution in the
proton. The correlation function shows a strong dependence on kinematical
variables. We discuss a possible interplay of perturbative and nonperturbative
effects.


title:
The Influence of an External Chromomagnetic Field on Color
  Superconductivity

abstract:
  We study the competition of quark-antiquark and diquark condensates under the
influence of an external chromomagnetic field modelling the gluon condensate
and in dependence on the chemical potential and temperature. As our results
indicate, an external chromomagnetic field might produce remarkable qualitative
changes in the picture of the color superconducting (CSC) phase formation. This
concerns, in particular, the possibility of a transition to the CSC phase and
diquark condensation at finite temperature.


title: Debye Screening Mass from effective Potentials in Lattice Gauge Theory

abstract:
  In this paper, we use a definition of the Debye screening mass in SU(2) pure
gauge theory at high temperature in 3+1 dimensions, that makes use of the walls
between different $Z_2$ domains. We show, that this definition enables us to
unambiguously obtain the Debye Screening mass from the curvature of the
effective potential for the Polyakov loops calculated in the modified axial
gauge. Using an approach on asymmetric lattices, we obtain numerical values for
the Debye mass and compare them to perturbative as well as Monte-Carlo results.
Our resulting Debye-Masses are significantly higher than the one-loop
perturbative one. They are within the errors in agreement with those obtained
by Monte-Carlo methods. Open questions are discussed.


title: Scaling phenomena from non-linear evolution in high energy DIS

abstract:
  The numerical solutions of the non-linear evolution equation are shown to
display the ``geometric'' scaling recently discovered in the experimental data.
The phenomena hold both for proton and nucleus targets for all $x$ below
$10^{-2}$ and $0.25 {\rm GeV^{2}}\le Q^2 \le 2.5\times10^3 {\rm GeV^{2}}$. The
scaling is practically exact (few percent error) in the saturation region. In
addition, an approximate scaling is found in the validity domain of the linear
evolution where it holds with about 10% accuracy.
  Basing on the scaling phenomena we determine the saturation scale $Q_s(x)$
and study both its $x$-dependence and the atomic number dependence for the
nuclei.


title:
Classical Limit of Time-Dependent Quantum Field Theory-a Schwinger-Dyson
  Approach

abstract:
  We rewrite the Martin-Siggia-Rose (MSR) formalism for the statistical
dynamics of classical fields in a covariant second order form appropriate for
the statistical dynamics of relativistic field theory. This second order
formalism is related to a rotation of Schwinger's closed time path (CTP)
formalism for quantum dynamics, with the main difference being that certain
vertices are absent in the classical theory. These vertices are higher order in
an $\hbar$ expansion. The structure of the second order formulation of the
Schwinger Dyson (S-D) equations is identical to that of the rotated CTP
formalism apart from initial conditions on the Green's functions and the
absence of these vertices. We then discuss self-consistent truncation schemes
based on keeping certain graphs in the two-particle irreducible effective
action made up of bare vertices and exact Green's functions.


title: Non-linear evolution and parton distributions at low x

abstract:
  We suggest a new procedure for extrapolating the parton distributions from
HERA to much higher energies. The procedure suggested consists of two steps.
First, we solve the non-linear evolution equation. Second, we introduce a
correcting function for which we write a DGLAP-type linear evolution equation.
The nonlinear equation is solved numerically and estimates for the saturation
scale, as well as for the gluon density at THERA and LHC energies are made.


title:
Next-to-leading order evolution of generalized parton distributions for
  HERA and HERMES

abstract:
  The QCD evolution of both unpolarized and polarized generalized parton
distributions (GPDs) to next-to-leading order (NLO) accuracy is presented, in
both the DGLAP and ERBL regions, for two appropriately symmetrized input
distributions based on conventional parton density functions. To illustrate the
relative size of the NLO corrections a comparison is made with leading order
evolution of the same distributions. For the first time, NLO results are given
for both small and large values of the skewedness parameter, $\zeta = x_{bj}$,
i.e. for all of the kinematic range relevant to HERA and HERMES.


title:
Distinguishing a MSSM Higgs Boson from the SM Higgs Boson at a Linear
  Collider

abstract:
  The decoupling properties of the Higgs sector in the Minimal Supersymmetric
Standard Model (MSSM) imply that a light CP-even Higgs boson discovered at the
Tevatron or LHC may closely resemble the Standard Model (SM) Higgs boson. In
this paper, we investigate how precision measurements of Higgs properties at a
Linear Collider (LC) can distinguish between a CP-even Higgs boson of the MSSM
and the SM Higgs boson. We review the expected theoretical behavior of the
partial widths and branching ratios for decays of the neutral MSSM Higgs bosons
with significant couplings to the W and Z bosons, including the leading
radiative corrections to the mixing angle alpha and tan beta-enhanced vertex
corrections. The general expectation is that the Higgs couplings to W+W-, ZZ, c
cbar and t tbar should quickly approach their SM values for increasing CP-odd
Higgs mass mA, while the couplings to b bbar and tau+ tau- do so more slowly.
Using the expected experimental and theoretical accuracy in determining SM
branching ratios and partial widths, we demonstrate the sensitivity of
measurements at the LC to variations in the MSSM parameters, with particular
attention to the decoupling limit. For a wide range of MSSM parameters, the LC
is sensitive to mA ~ 600 GeV almost independently of tan beta. For large values
of tan beta and some specific choices of MSSM parameters [e.g., A_t mu < 0 and
|A_t| ~ |mu| ~ O(M_S)], one of the CP-even Higgs bosons can be SM-like
independent of the value of mA. In the case of large deviations from the SM, we
present a procedure using Higgs coupling measurements to extract the
supersymmetric correction to the relation between the b quark mass and Yukawa
coupling.


title: On the standard model and parity conservation

abstract:
  Motivated by the theoretical paradox between the parity-violating gauge
symmetries of the standard model and the fundamental regulator, we propose that
the extension of the standard model to the high-energy region should be made by
adding effective high-dimension operators whose dynamics gives an infrared
scaling region, where not only the standard model appears as an asymptotic
chiral-gauge theory, but also vectorlike one-particle-irreducible functions are
induced to describe ``new physics''. We formulate the standard model on a
lattice by introducing a right-handed neutrino and a sterile left-handed
neutrino to form the high-dimension operators. Analyzing spectra and
one-particle-irreducible functions induced by these high-dimension operators,
we find that in the low-energy region, the parity-violating standard model is
consistently defined, while the parity-conservation gauge-symmetry is restored
in the high-energy region.


title: DIS data and the problem of saturation in small-x physics

abstract:
  New experimental data from HERA explore the region of very small x and small
and moderate $Q^2$. We study the role of unitarity corrections in the
description of these data. For that, we propose a model separating the small
and large components of the $q\bar q$ fluctuation. This model gives a unified
description of total and diffractive production in $\gamma^*p$ interactions. In
this model unitarity corrections are controlled by diffraction data.


title:
Q-ball formation: Obstacle to Affleck-Dine baryogenesis in the
  gauge-mediated SUSY breaking ?

abstract:
  We consider the Affleck-Dine baryogenesis comprehensively in the minimal
supersymmetric standard model with gauge-mediated supersymmetry breaking.
Considering the high temperature effects, we see that the Affleck-Dine field is
naturally deformed into the form of the Q ball. In the natural scenario where
the initial amplitude of the field and the A-terms are both determined by the
nonrenormalizable superpotential, we obtain only very a narrow allowed region
in the parameter space in order to explain the baryon number of the universe
for the case that the Q-ball formation occurs just after baryon number
production. Moreover, most of the parameter sets suited have already been
excluded by current experiments. We also find new situations in which the
Q-ball formation takes place rather late compared with baryon number creation.
This situation is more preferable, since it allows a wider parameter region for
naturally consistent scenarios, although it is still difficult to realize in
the actual cosmological scenario.


title: Quarkonium Production at High-Energy Colliders

abstract:
  The theoretical description of heavy quarkonium production at high-energy
p-pbar and e-p colliders is reviewed. Predictions based on non-relativistic QCD
factorisation are confronted with recent charmonium and bottomonium data from
the Tevatron and HERA. Potential shortcomings of the present theoretical
analyses are discussed, and the prospects for quarkonium physics at the
upgraded Tevatron and HERA colliders and at the LHC are summarised.


title: A See-Saw Mechanism with light sterile neutrinos

abstract:
  The usual see-saw mechanism for the generation of light neutrino masses is
based on the assumption that all of the flavours of right-handed (more
properly, sterile) neutrinos are heavy. If the sterile Majorana mass matrix is
singular, one or more of the sterile neutrinos will have zero mass before
mixing with the active (left-handed) neutrinos and be light after that mixing
is introduced. In particular, a rank 1 sterile mass matrix leads naturally to
two pseudo-Dirac pairs, one very light active Majorana neutrino and one heavy
sterile Majorana neutrino. For any pattern of Dirac masses, there exists a
region of parameter space in which the two pseudo-Dirac pairs are nearly
degenerate in mass. This, in turn, leads to large amplitude mixing of active
states as well as mixing into sterile states.


title: Neutrino masses or new interactions

abstract:
  Recent proposals to study the mass of the "electron" neutrino at a
sensitivity of 0.3 eV can be used to place limits on the right handed and
scalar charged currents at a level which improves on the present experimental
limits. Indeed the neglect of the possibility of such interactions can lead to
the inference of an incorrect value for the mass, as we illustrate.


title: Neutrino clustering and the Z-burst model

abstract:
  The possibility that the observed Ultra High Energy Cosmic Rays are generated
by high energy neutrinos creating "Z-bursts" in resonant interactions with the
background neutrinos has been proposed, but there are difficulties in
generating enough events with reasonable incident neutrino fluxes.
  We point out that this difficulty is overcome if the background neutrinos
have coalesced into "neutrino clouds" --- a possibility previously suggested by
some of us in another context. The limitations that this mechanism for the
generation of UHECRs places on the high energy neutrino flux, on the masses of
the background neutrinos and the characteristics of the neutrino clouds are
spelled out.


title: A next-to-leading order analysis of deeply virtual Compton scattering

abstract:
  We present a complete, next-to-leading-order (NLO), leading-twist QCD
analysis of deeply virtual Compton scattering (DVCS) observables, in the ${\bar
{MS}}$ scheme, and in the kinematic ranges of the H1, ZEUS and HERMES
experiments. We use a modified form of Radyushkin's ansatz for the input model
for the generalized parton distributions. We present results for leading order
(LO) and NLO for representative observables and find that they compare
favourably to the available data.


title: The Symmetry behind Extended Flavour Democracy and Large Leptonic Mixing

abstract:
  We show that there is a minimal discrete symmetry which leads to the extended
flavour democracy scenario constraining the Dirac neutrino, the charged lepton
and the Majorana neutrino mass term ($M_R$) to be all proportional to the
democratic matrix, with all elements equal. In particular, this discreet
symmetry forbids other large contributions to $M_R$, such as a term
proportional to the unit matrix, which would normally be allowed by a
$S_{3L}\times S_{3R}$ permutation symmetry. This feature is crucial in order to
obtain large leptonic mixing, without violating 't Hooft's, naturalness
principle.


title: QCD and Diffraction

abstract:
  I review some of the main results on hard diffraction, in their relation to
QCD, and indicate some of the strengths and weaknesses of the arguments. I also
make some suggestions for future work.


title: Resonant Amplification of Electroweak Baryogenesis at Preheating

abstract:
  We explore viable scenarios for parametric resonant amplification of
electroweak (EW) gauge fields and Chern-Simons number during preheating,
leading to baryogenesis at the electroweak (EW) scale. In this class of
scenarios time-dependent classical EW gauge fields, essentially
spatially-homogeneous on the horizon scales, carry Chern-Simons number which
can be amplified by parametric resonance up to magnitudes at which unsuppressed
topological transitions in the Higgs sector become possible. Baryon number
non-conservation associated with the gauge sector and the highly
non-equilibrium nature of preheating allow for efficient baryogenesis. The
requisite large CP violation can arise either from the time dependence of a
slowly varying Higgs field (spontaneous baryogenesis), or from a resonant
amplification of CP violation induced in the gauge sector through loops. We
identify several CP violating operators in the Standard Model and its minimal
extensions that can facilitate efficient baryogenesis at preheating, and show
how to overcome would-be exponential suppression of baryogenesis associated
with tunneling barriers.


title: On the Normalization of the Neutrino-Deuteron Cross Section

abstract:
  As is well-known, comparison of the solar neutrino fluxes measured in
SuperKamiokande (SK) by $\nu + e^- \to \nu + e^-$ and in the Sudbury Neutrino
Observatory (SNO) by $\nu_e + d \to e^- + p + p$ can provide a ``smoking gun''
signature for neutrino oscillations as the solution to the solar neutrino
puzzle. This occurs because SK has some sensitivity to all active neutrino
flavors whereas SNO can isolate electron neutrinos. This comparison depends
crucially on the normalization and uncertainty of the theoretical
charged-current neutrino-deuteron cross section. We address a number of effects
which are significant enough to change the interpretation of the SK--SNO
comparison.


title: Testing Fundamental Ideas with $\nu $'s

abstract:
  Fundamental questions in neutrino physics are likely to be resolved by
upcoming experiments. Neutrino masses require either new Higgs particles or
sterile neutrinos. Their masses, couplings, and habitat are yet to be
determined. Neutrino physics is particularly sensitive to brane ideas as the
extra particles are electroweak singlets and may free-range in the bulk. We
outline some of the important theoretical ideas for generating neutrino masses,
and how experiments will affect their longevity.


title:
Effects of different Form-factors in Meson-Photon-Photon Transitions and
  the Muon Anomalous Magnetic Moment

abstract:
  The exact form of the form-factor associated with a meson-photon-photon
vertex is not known. Different suggestions exist, based on constraints from QCD
and on recent experiments. Four different form-factors are studied in this
article.
  We calculate decay rates for the decays $\pi^{0}\to \gamma\gamma$, $\eta\to
\gamma e^{+}e^{-}$, $\eta\to \mu^{+}\mu^{-} e^{+}e^{-}$} and $\eta\to
e^{+}e^{-} e^{+}e^{-}$ and cross sections for the processes $e^{+}e^{-}\to PS
e^{+}e^{-}$, where $PS=\pi^{0}$, $\eta$ or $\eta'$. The results depend on the
choice of form-factor and we examine if the differences are large enough to
distinguish in upcoming experiments.
  The dominant part of the light-by-light contribution to the muon anomalous
magnetic moment is also calculated. Here the uncertainty around the choice of
form-factor implies that it is possible to estimate a smallest error in the
theoretical value of this contribution.


title: The Search for New Physics in D^0 --> gamma gamma Decay

abstract:
  We present main results of the investigation of the rare decay mode D^0
-->gamma gamma, in which the long distance contributions are expected to be
dominant. Using the Heavy Quark Chiral Lagrangian we have considered the
anomaly contribution which relates to the annihilation part of the weak
Lagrangian and the one - loop pi, K diagrams. The loop contributions which are
proportional to g and contain the a_1 Wilson coefficient are found to dominate
the decay amplitude. The branching ratio is then calculated to be (1.0+-0.5)x
10^{-8}. Observation of an order of magnitude larger branching ratio could
signal new physics.


title:
NLO QED corrections to ISR in e+ e- annihilation and the measurement of
  \sigma(e+ e- \to hadrons) using tagged photons

abstract:
  The leptonic tensor for the process $e^+ e^- \to \gamma+\gamma^*$, which
describes the next-to-leading order virtual and soft QED corrections to initial
state radiation in $e^+ e^-$ annihilation with emission of an extra virtual
photon decaying into hadrons, is calculated. A Monte Carlo generator for the
reaction $e^+ e^- \to \gamma + \pi^+ \pi^-$ has been set up which includes
these corrections. It thus describes configurations where the invariant mass of
the hadrons plus photon is very close to $\sqrt{s}$. Predictions for cms
energies of 1 to 10 GeV, corresponding to the energies of DAPHNE and B-meson
factories, are presented. The possibility for an accurate measurement using
tagged photons of $\sigma(e^+ e^- \to hadrons)$, which plays an important role
in the theoretical description of the muon anomalous magnetic moment and the
running of the electromagnetic coupling, is discussed.


title: What can we learn by probing Trans-Planckian physics

abstract:
  In this talk we address the issue of how the observables in our present
Universe are affected by processes that may have occured at superplanckian
energies (referred to as the {\it transplanckian regime}). For example, the
origin of the cosmological perturbation spectrum. We model the transplanckian
regime by introducing a 1-parameter family of smooth non-linear dispersion
relations which modify the frequencies at very short distances. For this family
of dispersions, we present the exact solutions and show that the CMBR spectrum
is that of a (nearly) black body, and that the adiabatic vacuum is the only
choice for the initial conditions. A particular feature of the family of
dispersion functions chosen is the production of ultralow frequencies at very
high momenta $k$ (for $k>M_P$). Modes with ultralow frequencies equal or less
than the current Hubble rate are still frozen today. Therefore, their energy
today provides a strong candidate for the dark energy of the Universe.


title: Dark Energy from teh Trans-Planckian regime

abstract:
  As yet, there is no underlying fundamental theory for the transplanckian
regime. There is a need to address the issue of how the observables in our
present Universe are affected by processes that may have occurred at
superplanckian energies (referred to as the transplanckian regime.
Specifically, we focus on the impact the transplanckian regime has on the dark
energy. We model the transplanckian regime by introducing a 1-parameter family
of smooth non-linear dispersion relations which modify the frequencies at very
short distances. A particular feature of the family of dispersion functions
chosen is the production of ultralow frequencies at very high momenta $k$ (for
$k>M_P$). We show that the range of modes with frequencies equal or less than
the current Hubble rate $H_0$ which are still frozen today provides a strong
candidate for the dark energy of the Universe.


title: Nonabelian alpha_s^3/(m_q r^2) heavy-quark-antiquark potential

abstract:
  We calculate the leading mass-suppressed two-loop contribution, proportional
to alpha_s^3/(m_q r^2), to the potential of a heavy quark-antiquark system.
This contribution originates in the nonabelian nature of quantum chromodynamics
(QCD) and has no analogue in quantum electrodynamics (QED). For this purpose,
we elaborate a technique based on the implementation of the threshold expansion
within the effective theory of nonrelativistic QCD (NRQCD). We discuss
phenomenological implications of our result for heavy-quarkonium physics. We
also confirm a previous result for the two-loop O(alpha_s^2) correction to the
static potential.


title:
B --> K^* \tau^+ \tau^- decay in the general two Higgs doublet model
  including the neutral Higgs boson effects

abstract:
  We study the CP violating asymmetry, the forward-backward asymmetry of the
lepton pair and the CP asymmetry in the forward backward asymmetry for the
exclusive decay $B --> K^* \tau^+ \tau^- in the general two Higgs doublet model
including the neutral Higgs boson effects. We analyse the dependencies of these
quantities on the model III parameters. We found that the physical parameters
studied above are at the order of the magnitude 1% and neutral Higgs boson
effects are detectable for large values of the coupling
\bar{\xi}_{N,\tau\tau}^D.


title: On Testing for New Couplings in Top Quark Decay

abstract:
  To quantitatively assay future measurements of competing observables in t -->
W b decay, we consider the g_{V-A} coupling values of the helicity decay
parameters versus those for "(V-A)+ Single Additional Lorentz Structures".
There are 2 dynamical phase-type ambiguities. Associated with the latter (f_M +
f_E) ambiguity, there are 3 very interesting numerical puzzles at the 0.1%
level. This evidence for the presence of tensorial couplings in t-decay is a
consequence of the empirical value of m_W/m_t and the small, but non-zero ratio
m_b/m_t. Measurement of the sign of eta_L = 0.46 (SM) due to the large
interference between the W longitudinal/transverse amplitudes could exclude
such tensorial couplings. Similarly, measurements of eta_L and eta_L^{'} could
resolve the case of a partially-hidden T-violation associated with the
additional (f_M + f_E) coupling.


title: Three Numerical Puzzles and the Top Quark's Chiral Weak-Moment

abstract:
  Versus the standard model's t --> W b decay helicity amplitudes, three
numerical puzzles occur at the 0.1 % level when one considers the amplitudes in
the case of an additional (f_M + f_E) coupling of relative strength 53 GeV. The
puzzles are theoretical ones which involve the t --> W b decay helicity
amplitudes in the two cases, the relative strength of this additional coupling,
and the observed masses of these three particles. A deeper analytic realization
is obtained for two of them. Equivalent realizations are given for the
remaining one. An empirical consequence of these analytic realizations is that
it is important to search for effects of a large chiral weak-moment of the
top-quark, the effective mass-scale is about 53 GeV. A full theoretical
resolution would include relating the origin of such a chiral weak-moment and
the mass generation of the top-quark, the W-boson, and probably the b-quark.


title: Neutrino Oscillations with Two $\Delta m^2$ Scales

abstract:
  An approximation that is often used in fits to reactor and atmospheric
neutrino data and in some studies of future neutrino oscillation experiments is
to assume one dominant scale, $\Delta m^2$, of neutrino mass squared
differences, in particular, $\Delta m^2_{atm} \sim 3 \times 10^{-3}$ eV$^2$.
Here we investigate the corrections to this approximation arising from the
quantity $\Delta m^2_{sol}$ relevant for solar neutrino oscillations, assuming
the large mixing angle solution. We show that for values of
$\sin^2(2\theta_{13}) \sim 10^{-2}$ (in the range of interest for long-baseline
neutrino oscillation experiments with either intense conventional neutrino
beams such as JHF-SuperK or a possible future neutrino factory) and for $\Delta
m^2_{sol} \sim 10^{-4}$ eV$^2$, the contributions to $\nu_\mu \to\nu_e$
oscillations from both CP-conserving and CP-violating terms involving
$\sin^2(\Delta m^2_{sol}L/(4E))$ can be comparable to the terms involving
$\sin^2(\Delta m^2_{atm}L/(4E))$ retained in the one-$\Delta m^2$
approximation. Accordingly, we emphasize the importance of performing a full
three-flavor, two-$\Delta m^2$ analysis of the data on $\nu_\mu \to \nu_e$
oscillations in a conventional-beam experiment and $\nu_e \to \nu_\mu$,
$\bar\nu_e \to \bar\nu_\mu$ oscillations at a neutrino factory. We also discuss
a generalized analysis method for the KamLAND reactor experiment, and note how
the information from this experiment can be used to facilitate the analysis of
the subsequent data on $\nu_\mu \to \nu_e$ oscillations. Finally, we consider
the analysis of atmospheric neutrino data and present calculations of matter
effects in a three-flavor, two-$\Delta m^2$ framework relevant to this data and
to neutrino factory measurements.


title: Universal Extra Dimensions and the Muon Magnetic Moment

abstract:
  We analyze the muon anomalous magnetic moment in the context of universal
extra dimensions. Our computation shows that the bound from electroweak data on
the size of these dimensions allows only a small shift in the muon magnetic
moment given by Kaluza-Klein modes of standard model fields. In the
well-motivated case of two universal extra dimensions, additional contributions
arising from physics at scales where the effective 6-dimensional standard model
breaks down, given by dimension-ten operators, have a natural size comparable
to the sensitivity of the muon (g-2) experiment at BNL.


title: One-Loop QCD Corrections to the Thermal Wilson Line Model

abstract:
  We calculate the time independent four-point function in high temperature (T)
QCD and obtain the leading momentum dependent terms. Furthermore, we relate
these derivative interactions to derivative terms in a recently proposed finite
T effective action based on the SU(3) Wilson Line and its trace, the Polyakov
Loop. By this procedure we thus obtain a perturbative matching at finite T
between QCD and the effective model. In particular, we calculate the leading
perturbative QCD-correction to the kinetic term for the Polyakov Loop.


title: Z decay into two massless gauge bosons in a magnetic field

abstract:
  An investigation of the processes Z to gluon-gluon and Z to photon-photon in
a background magnetic field is presented. For homogeneous fields corrections to
the charged fermion propagator can be calculated in leading orders of the
magnetic field. This work examines the first order contributions of the
corrected propagator to decays that are otherwise zero. Results of the decay
rates for varying field strengths are included.


title: Excitation of Nucleon Resonances

abstract:
  I discuss developments in the area of nucleon resonance excitations that are
necessary to bring our understanding of nucleon structure in the regime of
strong QCD to a qualitatively new level. They involve the collection of high
quality data in various channels, a more rigorous approach in the search for
"missing" quark model states, an effort to compute some critical quantities in
nucleon resonance excitations from first principles, i.e. QCD, and a proposal
aimed at obtaining an understanding of a fundamental quantity in nucleon
structure.


title: LMA MSW Solution in the Minimal $SU(3)_L \times U(1)_N$ Gauge Model

abstract:
  The minimal $SU(3)_L \times U(1)_N$ gauge model for $(\nu,\ell,\ell^C)$
equipped with the (approximate) $L_e-L_\mu-L_\tau$ symmetry and a discrete
$Z_4$ symmetry is found to provide radiative neutrino masses compatible with
the LMA MSW solution.


title: The Muon Anomalous Magnetic Moment - Significance of the New Measurement

abstract:
  Theoretical calculations of the hadronic contribution to the muon anomalous
magnetic moment utilize experimental data from e+e- annhilation and tau decay.
The data provide input to a dispersion relation. I contend that it is not
possible to put error bounds on the dispersion-relation calculation absent
proof - not presently available - that the amplitudes in question are
polynomially bounded. Examples are provided. Additional pertinent references
have been added to an earlier version of this posting.


title:
A general algorithm to generate unweighted events for next-to-leading
  order calculations in electron-positron annihilation

abstract:
  Given a next-to-leading order calculation, we show how to set up a computer
program, which generates a sequence of unweighted momentum configurations, each
configuration containing either n or n+1 four-vectors, such that for any
infrared safe observable the average over these configurations coincides with
the NLO calculation up to errors of order y_res. The core of the algorithm is a
method to combine real emission and virtual corrections on a point-by-point
basis in hard phase space. The algorithm can be implemented on top of existing
NLO calculations.


title: T-odd correlation in the $K_{l 3 \gamma}$-decay

abstract:
  The dependence of the $K^+ \to \pi^0 l^+ \nu_l \gamma$ decay width on the
$T$-odd kinematical variable, $ \xi = {\vec q \cdot [\vec p_l \times \vec
p_\pi]} / {M^3}$, is studied at the tree and one-loop levels of Standard Model.
It is shown that at the tree level this decay width is the even function of
$\xi$, while the odd contribution arises due to the electromagnetic final state
interaction. This contribution is determined by imaginary parts of one-loop
diagrams. The calculations performed show that the $\xi$-odd contribution to
the $K^+ \to \pi^0 e^+ \nu_e \gamma$ and $K^+ \to \pi^0 \mu^+ \nu_\mu \gamma$
decay widths is four orders of magnitude smaller than even contribution coming
from the tree level of SM.


title: Theoretical Aspects of Dark Matter Detection

abstract:
  Direct and indirect dark matter detection relies on the scattering of the
dark matter candidate on nucleons or nuclei. Here, attention is focused on dark
matter candidates (neutralinos) predicted in the minimal supersymmetric
standard model and its constrained version with universal input soft
supersymmetry-breaking masses. Current expectations for elastic scattering
cross sections for neutralinos on protons are discussed with particular
attention to satisfying all current accelerator constraints as well as insuring
a sufficient cosmological relic density to account for the dark matter in the
Universe.


title: Supernova neutrinos: Earth matter effects and neutrino mass spectrum

abstract:
  We perform a detailed study of the Earth matter effects on supernova
neutrinos. The dependences of these effects on the properties of the original
neutrino fluxes, on the trajectory of the neutrinos inside the Earth and on the
oscillation parameters are described. We show that, for a large fraction (60 %)
of the possible arrival times of the signal, the neutrino flux crosses a
substantial amount of the matter of the Earth at least for one of the existing
detectors. For oscillation parameters from the LMA solution of the solar
neutrino problem the Earth matter effect consists in an oscillatory modulation
of the $\barnue$ and/or $\nu_e$ energy spectra. The relative deviation with
respect to the undistorted spectra can be as large as 20-30 % for E> 20 MeV and
70-100 % for E> 40 MeV. For parameters from the
  SMA and LOW solutions the effect is localized at low energies (E<10 MeV) and
is not larger than 10 %. The Earth matter effects can be revealed (i) by the
observation of oscillatory distortions of the energy spectra in a single
experiment and (ii) by the comparison between the spectra at different
detectors. For a supernova at distance D=10 Kpc, comparing the results of
SuperKamiokande (SK), SNO and LVD experiments one can establish the effect at
(2-3) \sigma level, whereas larger statistical significance ((4-5) \sigma) is
obtained if two experiments of SK-size or larger are available. Studies of the
Earth matter effect will select or confirm the solution of the solar neutrino
problem, probe the mixing U_{e 3} and identify the hierarchy of the neutrino
mass spectrum.


title: Approximate solutions for the skyrmion

abstract:
  We reconsider the Euler-Lagrange equation for the Skyrme model in the
hedgehog ansatz and study the analytical properties of the solitonic solution.
In view of the lack of a closed form solution to the problem, we work on
approximate analytical solutions. We show that Pade approximants are well
suited to continue analytically the asymptotic representation obtained in terms
of a power series expansion near the origin, obtaining explicit approximate
solutions for the Skyrme equations. We improve the approximations by applying
the 2-point Pade approximant procedure whereby the exact behaviour at spatial
infinity is incorporated. An even better convergence to the exact solution is
obtained by introducing a modified form for the approximants. The new
representations share the same analytical properties with the exact solution at
both small and large values of the radial variable r.


title: Rapidity particle spectra in sudden hadronization of QGP

abstract:
  We show that the remaining internal longitudinal flow of colliding quarks in
nuclei offers a natural explanation for the diversity of rapidity spectral
shapes observed in Pb--Pb 158AGeV nuclear collisions. Thus QGP sudden
hadronization reaction picture is a suitable approach to explain the rapidity
spectra of hadrons produced.


title:
Four-dimensional lattice results on the MSSM electroweak phase
  transition

abstract:
  We present the results of our large scale 4-dimensional (4d) lattice
simulations for the MSSM electroweak phase transition (EWPT). We carried out
infinite volume and continuum limit extrapolations and found a transition whose
strength agrees well with perturbation theory. We determined the properties of
the bubble wall that are important for a successful baryogenesis.


title: The primordial curvature perturbation in the ekpyrotic Universe

abstract:
  In the ekpyrotic scenario the Universe is initially collapsing, the energy
density coming from a scalar field with a negative exponential potential. On
the basis of a calculation ignoring the gravitational back-reaction the authors
of the scenario claim that during collapse the vacuum fluctuation creates a
perturbation in the comoving curvature, which has a flat spectrum in accordance
with observation. In this note the back-reaction is included, and it is found
that the spectrum during collapse is strongly scale-dependent with negligible
magnitude. The spectrum is continuous across the bounce if the spacetime is
smooth, making it unlikely that the ekpyrotic scenario can be compatible with
observation.


title: Hunting the Higgs Boson(s)

abstract:
  I give a brief review of some of the opportunities and challenges that could
arise in our quest to unravel the Higgs sector that very probably underlies
electroweak symmetry breaking. In particular, I review scenarios with an
extended Higgs sector that allow for a heavy SM-like Higgs boson and/or make
discovery more difficult while at the same time maintaining consistency with
current limits and precision electroweak constraints.


title: Physics Opportunities with Polarized e- and e+ Beams at TESLA

abstract:
  Beam polarization at e+ e- linear colliders will be a powerful tool for high
precision analyses. Often it is assumed that the full information from
polarization effects is provided by polarization of the electron beam and no
further information can be obtained by the simultaneous polarization of the
positrons. In this paper we point out the advantages of polarizing both beams,
and summarize the polarization-related results of the Higgs, Electroweak, QCD,
SUSY and Alternative Theories working groups of the ECFA/DESY workshop for a
planned linear collider operating in the energy range sqrt{s}= 500-800 GeV.


title: On the dbar/ubar Asymmetry and Parton Distributions

abstract:
  We discuss the impact of different measurements of the dbar/ubar asymmetry in
the extraction of parameterizations of parton distribution functions.


title: GUT Implications from Neutrino Mass

abstract:
  An overview is given of the experimental neutrino mixing results and types of
neutrino models proposed, with special attention to the general features of
various GUT models involving intra-family symmetries and horizontal flavor
symmetries. Many of the features are then illustrated by a specific SO(10) SUSY
GUT model formulated by S.M. Barr and the author which can explain all four
types of solar neutrino mixing solutions by various choices of the right-handed
Majorana mass matrix. The quantitative nature of the model's large mixing angle
solution is used to compare the reaches of a neutrino super beam and a neutrino
factory for determining the small U_{e3} mixing matrix element.


title: Scalar Mesons, Glueballs, Instantons and the Glueball/Sigma

abstract:
  We include instanton effects in QCD sum rules for coupled scalar glueballs
and mesons. We find a light glueball/sigma as in earlier studies without
instantons, but in a lattice-type pure instanton model the light glueball/sigma
is not found. In the 1-2 Gev region we now find that lightest I=0 meson, in the
region of the f$_o$(1370), has no direct glueball mixing, with the instanton
loop replacing the glueball component. The lightest scalar mainly glueball in
the region of the f$_o$(1500) is sensitive to the choice of nonperturbative
gluonic parameters.


title: B -> K eta(') decay in perturbative QCD

abstract:
  We compute B->K eta' branching ratio using perturbative QCD approach. We show
that a triangular relation among amplitudes for B^0->K^0 pi^0, B^0->K^0 eta,
B^0->K^0 eta' receives large corrections from SU(3) breaking effects. If
experimental value will come closer to the lower limit of the present BELLE
data there will be a possibility to understand the large branching ratio of
B^0->K^0 eta'. Otherwise, we perhaps need to modify our understanding of eta'
meson, for example, inclusion of a possible admixture of gluonium state.


title: Heavy quark distribution functions in heavy baryons

abstract:
  Using the Bethe-Salpeter (B-S) equations for heavy baryons Lambda_Q, Sigma_Q,
Xi_Q and Omega_Q (Q=b or c), which were established in previous work, we
calculate the heavy quark distribution functions in these baryons. The
numerical results indicate that these distribution functions have an obvious
peak at some fraction, alpha_0, of the baryon's light-cone ``plus'' momentum
component carried by the heavy quark, and that as m_Q becomes heavier this peak
becomes sharper and closer to 1. The dependence of the distribution functions
on various input parameters in the B-S model is also discussed. The results are
seen to be qualitatively similar to an existing phenomenological model.


title: Exploring the construction of "Reference" triangle through unitarity

abstract:
  Motivated by the possibility of the low value of sin2\beta in the
measurements of BABAR and BELLE collaborations, we have explored the possibilty
of construction of reference unitarity triangle using the unitarity of the CKM
matrix, the existence of nonzero CP violating phase \delta and the experimental
values of the well known CKM elements, without involving any inputs from the
processes which might include the new physics effects. The angles of the
reference triangle are evaluated by finding \delta through the Jarlskog's
rephasing invariant parameter J. The present data and the unitarity of the CKM
matrix give \delta=50^o \pm 20^o, which translates to 130^o \pm 20^o in the
second quadrant. The corresponding range for sin2\beta is 0.21 to 0.88. This
range is broadly in agreement with the recently updated BABAR and BELLE
results. However, a value of \sin2 \leq 0.2, advocated by Silva and Wolfenstein
as a benchmark for new physics, would suggest a violation in the three
generation unitarity and would hint towards the existence of a fourth
generation. Further, the future refinements in the CKM elements will push the
lower limit on sin2\beta still higher.


title:
Calculation of the cross section for the pion diffractive dissociation
  into two jets

abstract:
  Contribution of the gluon distribution in the nucleon to the cross section
for the pion diffractive dissociation into two jets has been calculated
recently. In addition, we present here calculation of contribution of the quark
distributions to this process.
  It is expected usually that the quark contributions are much smaller than the
gluon one at high energies. We show that, under the conditions of the E791
experiment, the quark contributions are as significant as the gluon one, so
that the total cross section exceeds several times those with only gluon
contribution.
  Nevertheless, the distribution of jets in longitudinal momentum fractions
does not change significantly and remains qualitatively the same. We compare
our results with the data from the E791 experiment.


title: Symmetry Reduction, Gauge Transformation and Orbifold

abstract:
  We study a mechanism of symmetry reduction in a higher-dimensional field
theory upon orbifold compactification. Split multiplets appear unless all
components in a multiplet of a symmetry group have a common parity on an
orbifold. A gauge transformation property is also examined.


title: Tachyonic Preheating and Spontaneous Symmetry Breaking

abstract:
  We discuss the recent scenario of tachyonic preheating at the end of
inflation as a consequence of a tachyonic mass term in the scalar field
responsible for spontaneous symmetry breaking. We use 3D lattice simulations to
expore this very non-perturbative and non-linear phenomenon, which occurs due
to the spinodal instability of the scalar field. Tachyonic preheating is so
efficient that symmetry breaking typically completes within a single
oscillation of the field distribution as it rolls towards the minimum of its
effective potential.


title: Experimental introduction to extra dimensions

abstract:
  A short review of phenomenological and experimental aspects of extra spatial
dimensions at colliders is presented.


title: A Minimal S^1/(Z_2 x Z_2') Orbifold GUT

abstract:
  We investigate supersymmetric SU(5) grand-unified theories (GUTs) realized in
5 space-time dimensions and broken down to the MSSM by SU(5)-violating boundary
conditions on a S^1/(Z_2 x Z_2') orbifold with two 3-branes. The
doublet-triplet splitting problem is entirely avoided by locating the MSSM
Higgs doublets on the brane on which SU(5) is not a good symmetry. An extremely
simple model is then described in which the MSSM matter is also located on this
SU(5)-violating brane. Although this model does not unify the MSSM matter
within SU(5) multiplets, it explains gauge coupling unification. A second model
with MSSM matter in the SU(5)-symmetric bulk preserves both the SU(5)
explanation of fermion quantum numbers as well as gauge-coupling unification.
Both models naturally avoid problematic SU(5) predictions for the Yukawa
couplings of the first two generations and are consistent with proton decay
constraints. We analyse the running of gauge couplings above the
compactification scale in terms of a 5d effective action and derive the
implications for the values of compactification scale, unification scale and of
the scale at which the bulk gauge theory becomes strongly coupled.


title:
Power Corrections in Deep Inelastic Scattering and Non-perturbative
  Light-front Dynamics

abstract:
  In this thesis, we have investigated the higher twist structure functions in
the recently developed method based on light-front Hamiltonian QCD. Because of
various special properties of light-front QCD, this is a more intuitive
approach towards deep inelastic scattering but has a well defined field
theoretic calculational procedure. Because our method is different from the
conventional one, we have obtained various new results. Also, it is easier to
explore many aspects which are difficult to understand in the conventional way.
The structure functions, twist four $F_L$ and $g_T$ contain non-trivial
interaction dependence in the operator structure and therefore involve
quark-gluon dynamics. We have shown that the intergrals of these are directly
related to the light-front Hamiltonian density and transverse spin operator
respectively. These are non-perturbative relations. We have also renormalized
the twist four longitudinal structure function and the full transverse spin
operator respectively upto one loop in light-front Hamiltonian perturbation
theory. We have investigated twist four $F_L$ for bound states like a meson in
1+1 dimensional QCD and for a positronium in 3+1 dimensional QED.


title:
Global oscillation analysis of solar neutrino data with helioseismically
  constrained fluxes

abstract:
  A seismic model for the Sun calculated using the accurate helioseismic data
predicts a lower $^{8}{B}$ neutrino flux as compared to the standard solar
model (SSM). However, there persists a discrepancy between the predicted and
measured neutrino fluxes and it seems necessary to invoke neutrino oscillations
to explain the measurements. In this work, we have performed a global, unified
oscillation analysis of the latest solar neutrino data (including the results
of SNO charged current rate) using the seismic model fluxes as theoretical
predictions. We determine the best-fit values of the neutrino oscillation
parameters and the $\chi^2_{\mathrm min}$ for both $\nu_e-\nu_{\mathrm active}$
and $\nu_e -\nu_{\mathrm sterile}$ cases and present the allowed parameter
regions in the $\Delta m^2 - \tan^2 \theta$ plane for $\nu_e-\nu_{\mathrm
active}$ transition. The results are compared with those obtained using the
latest SSM by Bahcall and his collaborators.


title: A Comprehensive Approach to Structure Functions

abstract:
  We present a model based on a dipole picture with a hard and a soft pomeron
in which large dipoles couple to the soft pomeron and small dipoles couple to
the hard pomeron. The parameters in the model are fixed by proton-proton
scattering and the proton structure function. The model is then applied
successfully to the proton charm structure function, the proton longitudinal
structure function, J/psi photoproduction, deep virtual Compton scattering, the
real photon-proton total cross section, the real photon-photon cross section,
and the photon structure function. Differences between our predictions and data
on charm production in real photon-photon interactions and the virtual
gamma-gamma cross section are discussed.


title: What is inside the nucleon?

abstract:
  We briefly review the structure of nucleon in the context of QCD, Constituent
Quark Model and Chiral Quark Model.


title: Theoretical Aspects of Azimuthal and Transverse Spin Asymmetries

abstract:
  We use Lorentz invariance and the QCD equations of motion to study the
evolution of functions that appear at leading (zeroth) order in a 1/Q expansion
in azimuthal asymmetries. This includes the evolution equation of the Collins
fragmentation function. The moments of these functions are matrix elements of
known twist two and twist three operators. We present the evolution in the
large N_c limit, restricted to the non-singlet case for the chiral-even
functions.


title: Unified approach to hard diffraction

abstract:
  Using a combination of S-Matrix and perturbative QCD properties in the small
x_{Bj} regime, we propose a formulation of hard diffraction unifying the
partonic (Ingelman-Schlein) Pomeron, Soft Colour Interaction and QCD dipole
descriptions.


title:
PDF uncertainties: A strong test of goodness of fit to multiple data
  sets

abstract:
  We present a new criterion for the goodness of global fits. It involves an
exploration of the variation of \chi^2 for subsets of data.


title:
Implication of a light radion on the RG evolution of higgs self coupling
  in the Randall-Sundrum model

abstract:
  In this paper we determine how the beta funtion of the higgs self coupling
\lambda at one loop order is modified by a light stabilized radion in the
Randall-Sundrum model. We then use the modified beta function to derive a lower
bound on the radion vev <\phi>, both for perturbative and non-perturbative
values of \lambda at the ultra violet cut off \Lambda. The lower bound on
<\phi> is obtained by demanding that the renormalized coupling \lambda (\mu) at
\mu =100 GeV be consistent with the present experimental bound of 110 GeV on
the higgs mass from LEP2 searches. We also show that if \lambda (\Lambda) is
sufficiently small then an upper bound on <\phi> can be determined by requiring
that \beta (\lambda)be positive over the relevant momentum range.


title: Higher-twist operator effects to parton densities at small x

abstract:
  We investigate the Q^2 evolution of parton distributions at small x values,
obtained in the case of flat initial conditions. The contributions of twist-two
and (renormalon-type) higher-twist operators of the Wilson operator product
expansion are taken into account. The results are in very good agreement with
deep inelastic scattering experimental data from HERA.


title: Degrees of Freedom and the Deconfining Phase Transition

abstract:
  There is a sharp increase in the relative number of degrees of freedom at the
deconfining phase transition. Characterizing this increase using the Polyakov
Loop model, we find that for a nearly second order deconfining phase
transition, the medium-induced energy loss turns on rapidly above T_c,
proportional to the relative number of degrees of freedom. Further, energy loss
is logarithmically dependent on the screening mass, and thus is sensitive to
nearly critical scattering.


title:
The Potential for Neutrino Physics at Muon Colliders and Dedicated High
  Current Muon Storage Rings

abstract:
  Conceptual design studies are underway for muon colliders and other
high-current muon storage rings that have the potential to become the first
true ``neutrino factories''. Muon decays in long straight sections of the
storage rings would produce precisely characterized beams of electron and muon
type neutrinos of unprecedented intensity. This article reviews the prospects
for these facilities to greatly extend our capabilities for neutrino
experiments, largely emphasizing the physics of neutrino interactions.


title: Estimates of the Nucleon Tensor Charge

abstract:
  Like the axial vector charges, defined from the forward nucleon matrix
element of the axial vector current on the light cone, the nucleon tensor
charge, defined from the corresponding matrix element of the tensor current, is
essential for characterizing the momentum and spin structure of the nucleon.
Because there must be a helicity flip of the struck quark in order to probe the
transverse spin polarization of the nucleon, the transversity distribution (and
thus the tensor charge) decouples at leading twist in deep inelastic
scattering, although no such suppression appears in Drell-Yan processes. This
makes the tensor charge difficult to measure and its non-conservation makes its
prediction model dependent. We present a different approach. Exploiting an
approximate SU(6)xO(3) symmetric mass degeneracy of the light axial vector
mesons (a1(1260), b1(1235) and h1(1170)) and using pole dominance, we calculate
the tensor charge. The result is simple in form and depends on the decay
constants of the axial vector mesons and their couplings to the nucleons, along
with the average transverse momentum of the quarks in the nucleon. The result
is compared with other model estimates.


title: Fermionic massive modes along cosmic strings

abstract:
  The influence on cosmic string dynamics of fermionic massive bound states
propagating in the vortex, and getting their mass only from coupling to the
string forming Higgs field, is studied. Such massive fermionic currents are
numerically found to exist for a wide range of model parameters and seen to
modify drastically the usual string dynamics coming from the zero mode currents
alone. In particular, by means of a quantization procedure, a new equation of
state describing cosmic strings with any kind of fermionic current, massive or
massless, is derived and found to involve, at least, one state parameter per
trapped fermion species. This equation of state exhibits transitions from
subsonic to supersonic regimes while the massive modes are filled.


title:
Radiative effects in scattering of polarized leptons by polarized
  nucleons and light nuclei

abstract:
  Recent developments in the field of radiative effects in polarized
lepton-nuclear scattering are reviewed. The processes of inclusive,
semi-inclusive, diffractive and elastic scattering are considered. The explicit
formulae obtained within the covariant approach are discussed. FORTRAN codes
POLRAD, RADGEN, HAPRAD, DIFFRAD and MASCARAD created on the basis of the
formulae are briefly described. Applications for data analysis of the current
experiments on lepton-nuclear scattering at CERN, DESY, SLAC and TJNAF are
illustrated by numerical results.


title: Review of BFKL

abstract:
  I describe the underlying physics behind the BFKL resummation and discuss
some of the recent ideas and results in this field. On the theoretical side I
consider the formalism in the next-to-leading logarithmic (NLL) approximation
and the interpretation of the large corrections. On the phenomenological side I
discuss several experiments that attempt to observe the BFKL effects in the
high energy limit.


title:
Parametric resonance at the critical temperature in high energy heavy
  ion collisions

abstract:
  Parametric resonance in soft modes at the critical temperature ($T_{c}$) in
high energy heavy ion collisions is studied in the case when the temperature
($T$) of the system is almost constant for a long time. By deviding the fields
into three parts, zero mode (condensate), soft modes and hard modes and
assuming that the hard modes are in thermal equilibrium, we derive the equation
of motion for soft modes at $T=T_{c}$. Enhanced modes are extracted by
comparing with the Mathieu equation for the condensate oscillating along the
sigma axis at $T=T_{c}$. It is found that the soft mode of $\pi$ fields at
about 174 MeV is enhanced.


title:
Single chargino production with R-parity lepton number violation in
  photon-photon collisions

abstract:
  We examine the process $\gamma \gamma \to \tilde{\chi}^{+} \tau^{-}$ at
photon-photon collider in the minimal supersymmetric standard model(MSSM) with
R-parity violation, where all the one-loop diagrams are considered. We mainly
discuss the effects of bilinear breaking terms, and conclude that their
contributions may be important compared with trilinear terms. Our results show
that the events of this process could be detectable at photon-photon colliders,
if the values of the parameters are favorable.


title:
Hyperon polarization in semi-inclusive deeply inelastic lepton-nucleon
  scattering at high energy

abstract:
  We calculate the polarizations for different octet hyperons produced in the
current fragmentation regions of the deeply inelastic lepton-nucleon
scatterings $\mu^-N \to \mu^- HX$ and $\nu_{\mu} N \to \mu^- HX$ at high energy
using different models for spin transfer in fragmentation processes. The
results show that measurements of those hyperon polarizations should provide
useful information to distinguish between different models in particular the
SU(6) and the DIS pictures used frequently in the literature. We found, in
particular, that measuring the polarization of $\Sigma^+$ produced in these
processes can give a better test to the validity of the different spin transfer
models.


title:
The Lund Fragmentation Process for a Multi-gluon String According to the
  Area Law

abstract:
  The Lund Area Law describes the probability for the production of a set of
colourless hadrons from an initial set of partons, in the Lund string
fragmentation model. In this paper we will present a general method to
implement the Area Law for a multi-gluon string state. The partonic states are
in general given by a perturbative QCD cascade and are consequently defined
only down to a cutoff in the energy momentum fluctuations. We will show that
our method defines the states down to the hadronic mass scale inside an
analytically calculable scenario.
  We will then show that there is a differential version of our process which
is closely related to the generalised rapidity range \lambda, which has been
used as a measure on the partonic states. We identify \lambda as the area
spanned between the directrix curve (the curve given by the parton energy
momentum vectors laid out in colour order, which determines the string surface)
and the average curve (to be called the P-curve) of the stochastic X-curves
(curves obtained when the hadronic energy-momentum vectors are laid out in rank
order). Finally we show that from the X-curve corresponding to a particular
stochastic fragmentation situation it is possible to reproduce the directrix
curve (up to one starting vector and a set of sign choices, one for each
hadron).


title: The $B_{s}\to K$ Form Factor in The Whole Kinematically Accessible Range

abstract:
  A systematic analysis is presented of the $B_{s}\to K$ form factor $f(q^{2})
$ in the whole range of momentum transfer $q^{2}$, which would be useful to
analyzing the future data on $B_{s}\to K$ decays and extracting $| V_{ub}|$.
With a modified QCD light cone sum rule (LCSR) approach, in which the
contributions cancel out from the twist 3 wavefunctions of $K$ meson, we
investigate in detail the behavior of $f(q^{2})$ at small and intermediate
$q^{2}$ and the nonperturbative quantity $f_{B^{\ast}}g_{B^{\ast}B_{s}K}$
$(f_{B^{\ast}}$ is the decay constant of $B^{\ast}$ meson and
$g_{B^{\ast}B_{s}K}$ the $B^{\ast}B_{s}K$ strong coupling), whose numerical
result is used to study $q^{2}$ dependence of $f(q^{2})$ at large $q^{2}$ in
the single pole approximation. Based on these findings, a form factor model
from the best fit is formulated, which applies to the calculation on $f(q^{2})$
in the whole kinematically accessible range. Also, a comparison is made with
the standard LCSR predictions.


title:
The Formation of Primary Galactic Nuclei during Phase Transitions in the
  Early Universe

abstract:
  A new mechanism describing the formation of protogalaxies is proposed, which
is based on the second- order phase transition in the inflation stage and the
domain wall formation upon the end of inflation. The presence of closed domain
walls with the size markedly exceeding the cosmological horizon at the instant
of their formation and the wall collapse in the postinflation epoch (when the
wall size becomes comparable with the cosmological horizon), which leads to the
formation of massive black hole clusters that can serve as nuclei for the
future galaxies. The black hole mass distributions obtained do not contradict
the available experimental data. The number of black holes with M ~ 100 solar
masses ($M_{\odot}$) and above is comparable with the number of Galaxies in the
visible Universe. Development of the proposed approach gives ground for a
principally new scenario of the galaxy formation in the model of hot Universe.


title:
Scaling in $\gamma^* p$ total cross sections and the generalized vector
  dominance/color dipole picture

abstract:
  The scaling in $\sigma_{\gamma^*p}$ cross sections (for $Q^2/W^2 << 1$) in
terms of the scaling variable $\eta = (Q^2 + m^2_0)/\Lambda^2 (W^2)$ is
interpreted in the generalized vector dominance/color-dipole picture (GVD/CDP).
The quantity $\Lambda^2 (W^2)$ is identified as the average gluon transverse
momentum absorbed by the $q \bar q$ state, $<\vec l^{~2}> = (1/6) \Lambda^2
(W^2)$. At any $Q^2$, for $W^2 \to \infty$,the cross sections for virtual and
real photons became universal, $\sigma_{\gamma^*p}(W^2,Q^2)/\sigma_{\gamma
p}(W^2) \to 1$.


title: Implications of New CMB Data for Neutralino Dark Matter

abstract:
  The combination of new cosmic microwave background data with cosmological
priors has determined the physical cold dark matter (cdm) density to be
$\Omega_{\rm cdm} h^2 = 0.13\pm0.01$. We find the corresponding regions of
parameters in the minimal supergravity model for which the lightest neutralino
is the cdm particle. We then compare with the muon anomalous magnetic moment
($a_\mu$) measurement, the mass of the lighter CP-even Higgs boson ($h^0$), the
trilepton search at the upgraded Fermilab Tevatron collider, and a direct
search for relic neutralinos. The intersection of $\Omega_{\rm cdm} h^2$ and
$a_\mu$ constraints selects $\tan\beta\approx 40-45$.


title: Softly Broken Supersymmetric Desert from Orbifold Compactification

abstract:
  A new viewpoint for the gauge hierarchy problem is proposed: compactification
at a large scale, 1/R, leads to a low energy effective theory with
supersymmetry softly broken at a much lower scale, \alpha/R. The hierarchy is
induced by an extremely small angle \alpha which appears in the orbifold
compactification boundary conditions. The same orbifold boundary conditions
break Peccei-Quinn symmetry, leading to a new solution to the \mu problem.
Explicit 5d theories are constructed with gauge groups SU(3) \times SU(2)
\times U(1) and SU(5), with matter in the bulk or on the brane, which lead to
the (next-to) minimal supersymmetric standard model below the compactification
scale. In all cases the soft supersymmetry-breaking and \mu parameters
originate from bulk kinetic energy terms, and are highly constrained. The
supersymmetric flavor and CP problems are solved.


title: Generalized parton distributions at large momentum transfer

abstract:
  The role of generalized parton distributions in wide-angle exclusive
reactions will be discussed. In contrast to deep virtual exclusive reactions
the wide angle processes offer the possibility of investigating the generalized
parton distributions at large momentum transfer.


title: Generalized parton distributions in the deuteron

abstract:
  We introduce generalized quark and gluon distributions in the deuteron, which
can be measured in exclusive processes like deeply virtual Compton scattering
and meson electroproduction. We discuss the basic properties of these
distributions, and point out how they probe the interplay of nucleon and parton
degrees of freedom in the deuteron wave function.


title: Baryonic Rare Decays of $\Lambda_b\to \Lambda \ell^+\ell^-$

abstract:
  We present a systematic analysis for the rare baryonic exclusive decays of
$\Lambda_b\to\Lambda l^+ l^- (l=e,\mu,\tau)$. We study the differential decay
rates and the di-lepton forward-backward, lepton polarization and various CP
asymmetries with a new simple set of form factors inspired by the heavy quark
effective theory. We show that most of the observables are insensitive to the
non-perturbative QCD effects. To illustrate the effect of new physics, we
discuss our results in an explicit supersymmetric extension of the standard
model, which contains new CP violating phases and therefore induces sizable CP
violating asymmetries.


title: Electromagnetic properties of heavy mesons in heavy quark limit

abstract:
  The electromagnetic (EM) form fators of the pseudoscalar and vector mesons
are calculated in the light-front framework. We extract these form factors from
the relevant matrix elements directly, instead of choosing the Breit frame. The
results show that the charge radius of the meson are related to both the first
and second longitudinal momentum square derivative of the momentum distribution
function. In addition, the static properties of the EM form factors and the
heavy quark symmetry of the charge radii are checked analytically when we take
the heavy quark limit.


title: Schwinger-Dyson approach to non-equilibrium classical field theory

abstract:
  In this paper we discuss a Schwinger-Dyson [SD] approach for determining the
time evolution of the unequal time correlation functions of a non-equilibrium
classical field theory, where the classical system is described by an initial
density matrix at time $t=0$. We focus on $\lambda \phi^4$ field theory in 1+1
space time dimensions where we can perform exact numerical simulations by
sampling an ensemble of initial conditions specified by the initial density
matrix. We discuss two approaches. The first, the bare vertex approximation
[BVA], is based on ignoring vertex corrections to the SD equations in the
auxiliary field formalism relevant for 1/N expansions. The second approximation
is a related approximation made to the SD equations of the original formulation
in terms of $\phi$ alone. We compare these SD approximations as well as a
Hartree approximation with exact numerical simulations. We find that both
approximations based on the SD equations yield good agreement with exact
numerical simulations and cure the late time oscillation problem of the Hartree
approximation. We also discuss the relationship between the quantum and
classical SD equations.


title: Neutrino Scattering in a Magnetic Field

abstract:
  Motivated by the evidence for a finite neutrino mass we examine anew the
interaction of neutrinos in a magnetic field. We present the rate for radiative
scattering for both massless and massive neutrinos in the standard model and
give the corresponding numerical estimates. We also consider the effects
arising from a possible neutrino magnetic moment.


title: Light Vector Meson Spectroscopy

abstract:
  The current situation for vector meson spectroscopy is outlined, and it is
shown that the data are inconsistent with the generally-accepted model for
meson decay. A possible resolution in terms of exotic (hybrid) mesons is given.
Although this hypothesis resolves some of the issues, fresh theoretical
questions are raised. It is argued that high-precision $e^+e^-$ annihilation
data provide an excellent laboratory for studying many aspects of
nonperturbative QCD.


title:
Pair Production of Smuons and Selectrons Near Threshold in e+ e- and e-
  e- Collisions

abstract:
  Non-zero width and Coulomb rescattering effects are analyzed for the pair
production of smuons and selectrons near the thresholds in e+ e- and e- e-
collisions, respectively. The excitation curves are predicted in a
gauge-invariant form. Energy cuts are designed to reduce irreducible
supersymmetric backgrounds.


title: Attempts at Explaining the NuTeV Observation of Di-Muon Events

abstract:
  The NuTeV Collaboration has observed an excess in their di-muon channel,
possibly corresponding to a long-lived neutral particle with only weak
interactions and which decays to muon pairs. We show that this can {\it not} be
explained by pair production of neutralinos in the target followed by their
decay far downstream in the detector via a $LLE$ R-parity violating (RPV)
operator, as suggested in the literature. In the parameter region allowed by
LEP the event rate is far too small. We propose instead a new neutralino
production method via $B$-mesons, which can fully explain the observation. This
is analogous to neutrino production via $\pi$-mesons. This model can be
completely tested and thus also possibly excluded with NOMAD data. If it is
excluded, the NuTeV observation is most likely not due to physics beyond the
Standard Model. Our model can also be tested at the current and future
$B$-factories. This opens up a new way of testing a long-lived neutralino LSP
at fixed-target experiments and thus a possibility to close the gap between
collider and cosmological tests of R-parity violation. We also discuss a
possible explanation in terms of a neutral heavy lepton mixing with the
Standard Model neutrinos. The flavour structure of the observation can be
accounted for but the production rate is far too low.


title: On Gribov's Ideas on Confinement

abstract:
  I comment on possible relations of Gribov's ideas on mechanism of confinement
with some phenomena in QCD and in supersymmetric gauge theories.


title:
Global Analysis of Solar Neutrinos with Magnetic Moment and Solar Field
  Profiles

abstract:
  A global statistical analysis of the pre-SNO solar neutrino data including
the rates and recoil electron spectrum in SuperKamiokande is made assuming the
solar neutrino deficit to be resolved by the interaction of the neutrino
magnetic moment with the solar magnetic field. Given the general
characteristics of the field profiles known to lead to the best event rate
predictions, several specific choices of profiles are assumed and global fits
investigated. Whereas previous studies revealed an excellent quality of the
rate fits within the magnetic moment solution to the solar neutrino problem,
the global fits are found to be only of reasonable quality and comparable to
the global oscillation fits. This is related to the difficulty of any
theoretical model to provide at present an adjustable prediction to the
spectral data.


title: Heavy quark colorimetry of QCD matter

abstract:
  We consider propagation of heavy quarks in QCD matter. Because of large quark
mass, the radiative quark energy loss appears to be qualitatively different
from that of light quarks at all energies of practical importance. Finite quark
mass effects lead to an in-medium enhancement of the heavy-to-light D/\pi ratio
at moderately large (5--10 GeV) transverse momenta. For hot QCD matter a large
enhancement is expected, whose magnitude and shape are exponentially sensitive
to the density of colour charges in the medium.


title: Weak annihilation in the rare radiative $B\to \rho\gamma$ decay

abstract:
  The ampitude of the $B\to\rho\gamma$ decay induced by the flavour-changing
neutral currents contains the penguin contribution and the weak-annihilation
contribution generated by the 4-quark operators in the effective Hamiltonian.
The penguin contribution is known quite well. We analyse the weak-annihilation
which is suppressed by the heavy-quark mass compared to the penguin
contribution.
  In the factorization approximation, the weak annihilation amplitude is
represented in terms of the leptonic decay constants and the meson-photon
matrix elements of the weak currents. The latter contain the $B\gamma$,
$\rho\gamma$ transition form factors and contact terms determined by the
equations of motion. We calculate the $B\gamma$ and $\rho\gamma$ form factors
within the relativistic dispersion approach and obtain numerical estimates for
the weak annihilation amplitude.


title: Proposed Post-LEP Benchmarks for Supersymmetry

abstract:
  We propose a new set of supersymmetric benchmark scenarios, taking into
account the constraints from LEP, b to s gamma, g_mu - 2 and cosmology. We work
in the context of the constrained MSSM (CMSSM) with universal soft
supersymetry-breaking masses and assume that R parity is conserved. We propose
benchmark points that exemplify the different generic possibilities, including
focus-point models, points where coannihilation effects on the relic density
are important, and points with rapid relic annihilation via direct-channel
Higgs poles. We discuss the principal decays and signatures of the different
classes of benchmark scenarios, and make initial estimates of the physics
reaches of different accelerators, including the Tevatron collider, the LHC,
and e+ e- colliders in the sub- and multi-TeV ranges. We stress the
complementarity of hadron and lepton colliders, with the latter favoured for
non-strongly-interacting particles and precision measurements. We mention
features that could usefully be included in future versions of supersymmetric
event generators.


title: Global duality in heavy flavor decays in the 't Hooft model

abstract:
  We average the decay width of a heavy meson in the t' Hooft model over the
heavy quark mass M with a smooth weight function. The averaging has support
over a few resonance spacings. We use the previously determined heavy meson
decay width which differs from the free quark width by a 1/M correction. In
contrast, we find that the averaged meson and quark widths differ by a 1/M^2
correction. We speculate on the relevance of our results to the
phenomenologically relevant case of 3+1 dimensional QCD.


title: Transversity single spin asymmetries

abstract:
  The theoretical aspects of two leading twist transversity single spin
asymmetries, one arising from the Collins effect and one from the interference
fragmentation functions, are reviewed. Issues of factorization, evolution and
Sudakov factors for the relevant observables are discussed. These theoretical
considerations pinpoint the most realistic scenarios towards measurements of
transversity.


title: Unknowns after the SNO Charged-Current Measurement

abstract:
  We perform a model-independent analysis of solar neutrino flux rates
including the recent charged-current measurement at the Sudbury Neutrino
Observatory (SNO). We derive a universal sum rule involving SNO and
SuperKamiokande rates, and show that the SNO neutral-current measurement can
not fix the fraction of solar $\nu_e$ oscillating to sterile neutrinos. The
large uncertainty in the SSM $^8$B flux impedes a determination of the sterile
neutrino fraction.


title: B --> rho l nu Decay and |V_{ub}|

abstract:
  B --> rho l nu decay is analyzed in the effective theory of heavy quark with
infinite mass limit. The matrix element relevant to the heavy to light vector
meson semileptonic decays is parametrized by a set of four heavy flavor-spin
independent universal wave functions at the leading order of effective theory.
The form factors are calculated at the leading 1/m_Q order using the light cone
sum rule method in the framework of effective theory. |V_{ub}| is then
extracted via B --> rho l nu decay mode.


title: Disoriented chiral condensate in presence of dissipation and noise

abstract:
  We have investigated the phase transition and disoriented chiral condensate
domain formation in linear sigma model. Solving the Langevin equation for the
linear $\sigma$ model, we have shown that for zero mass pions the fields
undergo phase transition above a certain temperature ($T_c$). For finite mass
pions, there is no phase transition. It was also shown that when the fields,
thermalised at temperature above $T_c$ are cooled down sufficiently rapidly,
disoriented chiral condensate domains are formed quite late in the evolution,
if the pions are assumed to be mass less. For massive pions, no large DCC
domain is formed.


title: Correlations of errors in a CP-violation neutrino factory experiment

abstract:
  An indirect CP-violation neutrino factory experiment is studied, including
simul taneous correlations of errors of the six oscillation parameters and a
matter ef fect normalisation parameter, C. It is found that for larger values
of $\theta_{13}$ ($3^\circ$), an uncertainty on the matter effect of the order
5% means t hat the optimal baseline for measurement of $\delta$ is reduced from
3000km to 2 000km. When the background fraction is assumed to be $10^{-3}$ the
optimal muon energy is also reduced from 50GeV to around 20GeV. An experiment
with L=2000km, $E_\mu=$20GeV is found to be sensitive to non-zero $\delta$ down
to around $\t heta_{13}\approx0.3^\circ$.


title:
Interference effects in the decay \phi\to \pi^{0}\pi^{0}\gamma and the
  coupling constant g_{\phi\sigma\gamma}

abstract:
  We study the radiative decay $\phi\to\pi^{0}\pi^{0}\gamma$ within the
framework of a phenomenological approach in which the contributions of
$\sigma$-meson, $\rho$-meson and $f_0$-meson are considered. We analyze the
interference effects between different contributions and utilizing the
experimental branching ratio for this decay we estimate the coupling constant
$g_{\phi\sigma\gamma}$.


title: Supersymmetric Models and Collider Signatures

abstract:
  We briefly review the SUGRA, GMSB and AMSB supersymmetry breaking models. We
then discuss the phenomenological differences between them and consequent
characteristic experimental signatures. This is followed by a review of the
discovery potential for supersymmetry at the Tevatron, LHC and a future e+e-
linear collider.


title:
Lepton-Flavor Violating Processes $l_{i}\to l_{j}\gamma$ in Topcolor
  Assisted Technicolor Models

abstract:
  We consider the lepton-flavor violating(LFV) processes $l_{i}\to l_{j}\gamma$
in the framework of topcolor assisted technicolor(TC2) models. We find that the
new gauge boson $Z^{\prime}$ predicted by TC2 models can give significantly
contributions to these processes via the flavor changing couplings. The present
experimental bound on the LFV process $\mu \to e\gamma$ gives severe
constraints on the TC2 models. In the case that the $Z^{\prime}$ mass $M_{Z}$
is consistent with other experimental constraints, we obtain constraints on the
lepton mixing factors $K_{\tau\mu}$ and $K_{\tau e}$. The future LFV
experiments will be probe of the TC2 models.


title: Polarized Parton Densities in the Nucleon

abstract:
  We present a new NLO QCD analysis of the world data on inclusive polarized
deep inelastic scattering. Comparing to our previous analysis: i) the values of
g_A and a_8=3F-D are updated ii) the MRST'99 instead of the MRST'98
parametrization for the input unpolarized parton densities is used and iii) the
recent SLAC E155 proton data on the spin asymmetry A1 are included in the
analysis. A new set of polarized parton densities is extracted from the data
and the sensitivity of the results to different positivity constraints is
discussed.


title: Spin structure functions and intrinsic motion of the constituents

abstract:
  The spin structure functions of the system of quasifree fermions on mass
shell are studied in a consistently covariant approach. Comparison with the
basic formulas following from the quark-parton model reveals the importance of
the fermion motion inside the target for the correct evaluation of the spin
structure functions. In particular it is shown, that regarding the moment
$\Gamma_{1}$, both the approaches are equivalent for the static fermions, but
differ by the factor 1/3 in the limit of massles fermions ($% m \ll p_0$, in
target rest frame). Some other sum rules are discussed as well.


title: Parity Violating Photoproduction of $\pi^\pm$ on the $\Delta$ Resonance

abstract:
  We analyze the real photon asymmetry $A^\pm_\gamma$ for the parity violating
(PV) $\pi^\pm$ production on the $\Delta$ resonance via the reactions ${\vec
\gamma} + p \to \Delta^+ \to \pi^+ + n$ and ${\vec \gamma} + d \to \Delta^0 + p
\to \pi^- + p + p$. This asymmetry is nonvanishing due to a PV $\gamma N
\Delta$ coupling constant, $d^\pm_\Delta$. We argue that an experimental
determination of this coupling would be of interest for hadron dynamics,
possibly shedding light on the S-wave/P-wave puzzle in the hyperon nonleptonic
decays and the violation of Hara's theorem in weak radiative hyperon decays.


title: A lower bound on the local extragalactic magnetic field

abstract:
  Assuming that the hard gamma-ray emission of Cen A is a result of synchrotron
radiation of ultra-relativistic electrons, we derive a lower bound on the local
extragalactic magnetic field, $B> 10^{-8}$ G. This result is consistent with
(and close to) upper bounds on magnetic fields derived from consideration of
cosmic microwave background distortions and Faraday rotation measurements.


title: Measuring transversity with T-odd single particle production

abstract:
  The transversity distribution can be measured at leading-twist in
single-particle inclusive DIS, where it appears in connection with chiral-odd
fragmentation functions. Among these functions, we focus on the time-reversal
odd ones. They occur in fragmentation to unpolarized hadrons or polarized
spin-one hadrons. Using a simple model, we show how these functions can be
non-vanishing and we discuss the asymmetries where they can be measured
together with the transversity distribution.


title:
High Energy Colliders as Black Hole Factories: The End of Short Distance
  Physics

abstract:
  If the fundamental Planck scale is of order a TeV, as the case in some
extra-dimensions scenarios, future hadron colliders such as the Large Hadron
Collider will be black hole factories. The non-perturbative process of black
hole formation and decay by Hawking evaporation gives rise to spectacular
events with up to many dozens of relatively hard jets and leptons, with a
characteristic ratio of hadronic to leptonic activity of roughly 5:1. The total
transverse energy of such events is typically a sizeable fraction of the beam
energy. Perturbative hard scattering processes at energies well above the
Planck scale are cloaked behind a horizon, thus limiting the ability to probe
short distances. The high energy black hole cross section grows with energy at
a rate determined by the dimensionality and geometry of the extra dimensions.
This dependence therefore probes the extra dimensions at distances larger than
the Planck scale.


title:
Lower Bound on the Propagation Speed of Gravity from Gravitational
  Cherenkov Radiation

abstract:
  Recently, interesting 4-D Lorentz violating models have been proposed, in
which all particles have a common maximum velocity $c$, but gravity propagates
(in the preferred frame) with a different maximum velocity $c_g \neq c$. We
show that the case $c_g < c$ is very tightly constrained by the observation of
the highest energy cosmic rays. Assuming a galactic origin for the cosmic rays
gives a conservative bound of $c-c_g < 2 \times 10^{-15} c$; if the cosmic rays
have an extragalactic origin the bound is orders of magnitude tighter, of order
$c-c_g < 2 \times 10^{-19} c$.


title:
Fixation of theoretical ambiguities in the improved fits to $xF_3$ CCFR
  data at the next-to-next-to-leading order and beyond

abstract:
  Using the results for the NNLO QCD corrections to anomalous dimensions of odd
$xF_3$ Mellin moments and N$^3$LO corrections to their coefficient functions we
improve our previous analysis of the CCFR'97 data for $xF_3$. The possibility
of extracting from the fits of $1/Q^2$-corrections is analysed using three
independent models,including infrared renormalon one. Theoretical quetion of
applicability of the renormalon-type inspired large-$\beta_0$ approximation for
estimating corrections to the coefficient functions of odd $xF_3$ and even
non-singlet $F_2$ moments are considered. The comparison with [1/1] Pad\'e
estimates is given. The obtained NLO and NNLO values of $\alpha_s(M_Z)$ are
supporting the results of our less definite previous analysis and are in
agreement with the world average value $\alpha_s(M_Z)\approx 0.118$. We also
present first N$^3$LO extraction of $\alpha_s(M_Z)$. The interplay between
higher-order perturbative QCD corrections and $1/Q^2$-terms is demonstrated.
The results of our studies are compared with those obtained recently using the
NNLO model of the kernel of DGLAP equation and with the results of the NNLO
fits to CCFR'97 $xF_3$ data, performed by the Bernstein polynomial technique.


title:
A Search for the Fourth SM Family Fermions and E_6 Quarks at $\mu
  ^{+}\mu ^{-}$ Colliders

abstract:
  The potential of $\mu ^{+}\mu ^{-}$ colliders to investigate the fourth SM
family fermions predicted by flavour democracy has been analyzed. It is shown
that muon colliders are advantageous for both pair production of fourth family
fermions and resonance production of fourth family quarkonia. Also isosinglet
quarks production at $\mu ^{+}\mu ^{-}$ colliders has been investigated.


title: Constraints on SUSY Gluonic Dipole Interaction from B\to K\pi Decays

abstract:
  In low energy SUSY theories exchange of gluino and squark with left-right
mixing can produce a large gluonic dipole interaction. In this paper we study
the effects of this interaction on $B\to K \pi$ using QCD improved
factorization method. The Standard Model predicts a smaller branching ratio for
$B^0 \to \bar K^0 \pi^0$ than experimental measured one. We find that within
the parameter space allowed from $B\to \gamma X_s$ constraint, the SUSY dipole
interaction can enhance this branching ratio to agree with the experimental
measurement. Combining recent data for all the four $\bar B^0 \to K^- \pi^+,
\bar K^0 \pi^0$ and $B^- \to K^- \pi^0, \bar K^0 \pi^-$ decay modes, we find
that the allowed parameter space is reduced significantly compared with that
using $B\to X_s \gamma$ data alone. It is found that even with these
constraints, the predictions for CP violation in these modes can be
dramatically different from those of the SM predictions.


title: Odderon in QCD

abstract:
  A review on how the Odderon idea does appear in QCD is given. In the last
years it has been developed a non-perturbative QCD approach based on the
stochastic vacuum model and a perturbative one based on resummation techniques
in the small x QCD region. Last developments on the perturbative analysis are
shown in some details, in particular in application to diffractive eta_c
production.