title: Solitons in nonlocal chiral quark models

abstract:
  Properties of hedgehog solitons in a chiral quark model with nonlocal
regulators are described. We discuss the formation of the hedgehog soliton, the
quantization of the baryon number, the energetic stability, the gauging and
construction of Noether currents with help of path-ordered P-exponents, and the
evaluation of observables. The issue of nonlocality is thoroughly discussed,
with a focus on contributions to observables related to the Noether currents.
It is shown that with typical model parameters the solitons are not far from
the weak nonlocality limit. The methods developed are applicable to solitons in
models with separable nonlocal four-fermion interactions.


title: Production of $\eta'$ from Thermal Gluon Fusion

abstract:
  We study the production of $\eta'$ from hadronizing thermal gluons using
recently proposed $\eta'-g-g$ effective vertex. The $\eta'$ yield is found to
be sensitive to the initial condition. At RHIC and LHC, the enhancement is
large enough to be easily detected.


title: Gluon propagators and quark confinement

abstract:
  The gluon propagator is investigated in Landau and in maximal center gauge
for the gauge group SU(2) by means of lattice gauge simulations. We find that
Gribov ambiguities arising from the implementation of Landau gauge have a small
influence on the propagator. In agreement with previous findings, we obtain
that the small momentum behavior is dominated by a mass, which is of order
$(1.48 \pm 0.05) \sqrt{\sigma}$, where $\sigma $ is the string tension. By
removing the confining vortices from the full Yang-Mills ensemble, we convert
full YM-theory into a theory which does not confine quarks. We find that in the
latter case the strength of the gluon propagator in the intermediate momentum
range is strongly reduced. The spectral functions which reproduce the numerical
data for the propagators are analyzed using a generalized Maximum Entropy
Method.


title: Probing colored glass via $q\bar{q}$ photoproduction

abstract:
  In this paper, we calculate the cross-section for the photoproduction of
quark-antiquark pairs in the peripheral collision of ultra-relativistic nuclei,
by treating the color field of the nuclei within the Color Glass Condensate
model. We find that this cross-section is sensitive to the saturation scale
$Q_s^2$ that characterizes the model. In particular, the transverse momentum
spectrum of the produced pairs could be used to measure the properties of the
color glass condensate.


title: Metric perturbations at reheating: the use of spherical symmetry

abstract:
  We consider decay of the inflaton with a quartic potential coupled to other
fields, including gravity, but restricted to spherical symmetry. We describe
analytically an early, quasilinear regime, during which inflaton fluctuations
and the metric functions are driven by nonlinear effects of the decay products.
We present a detailed study of the leading nonlinear effects in this regime.
Results of the quasilinear approximation, in its domain of applicability, are
found to be consistent with those of fully nonlinear lattice studies. We
discuss how these results may be promoted to the full three dimensions.


title: The Threshold t-tbar Cross Section at NNLL Order

abstract:
  The total cross section for top quark pair production close to threshold in
e+e- annihilation is investigated. Details are given about the calculation at
next-to-next-to-leading logarithmic order. The summation of logarithms leads to
a convergent expansion for the normalization of the cross section, and small
residual dependence on the subtraction parameter nu. A detailed analysis of the
residual nu dependence is carried out. A conservative estimate for the
remaining uncertainty in the normalization of the total cross section from QCD
effects is $\lesssim \pm 3%$. This makes precise extractions of the strong
coupling and top width feasible, and further studies of electroweak effects
mandatory.


title:
Branching ratios of $B_s\to (K^+K^-,K^0\bar{K}^0)$ and $B_d\to \pi^+
  \pi^- and determination of \boldmath{$\gamma (\phi_3)$

abstract:
  We explored various cases for the branching ratios (BRs) of $B_s\to K^+K^-$,
$B_s\to K^0\bar{K}^0$ and $B_d\to \pi^+ \pi^-$ decays. We study the possibility
of determining $\gamma $ by using the following the measurements: (a) BRs of
$B_s\to K^+K^-$, and $B_s\to K^0\bar{K}^0$; (b) the ratio of direct CP
asymmetries in $B_d\to \pi^+ \pi^-$ and $B_s\to K^+K^-$; (c) the mix-induced CP
asymmetry in $B_d\to \pi^+ \pi^-$; and (d) the angle of $\beta$.


title: Hadronic and Quark-Gluon Excitations of Dense and Hot Matter

abstract:
  We summarize recent developments in our understanding of low-mass
quark-antiquark excitations in hadronic matter under various different
conditions. This includes the thermodynamics of the chiral condensate, pions as
Goldstone bosons in normal nuclear matter, and excursions into extreme
territory of the QCD phase diagram: lepton pair production from a fireball
expanding through the transition boundary between the quark-gluon and hadron
pha ses of QCD.


title: Effective Higgs-quark-quark couplings from a heavy SUSY spectrum

abstract:
  In this paper we study the Yukawa Higgs-quark-quark interactions that are
generated from radiative corrections of squarks and gluinos, in the Minimal
Supersymmetric Standard Model. We compute the corrections to the effective
action for Higgs and quark fields that are produced by explicit integration, in
the path integral formalism, of all the squarks and gluinos, at the one-loop
level and order $\alpha_s$. In addition, we consider the limit of nearly
degenerate heavy squarks and gluinos, with masses much larger than the
electroweak scale, and derive the effective Lagrangian containing all the
relevant new local Higgs-quark-quark interactions. We show that these new
interactions do remain non-vanishing, even in the case of infinitely heavy
supersymmetric particles and, therefore, we demonstrate explicitly the
non-decoupling behavior of squarks and gluinos in Higgs bosons physics. We
present the set of new Yukawa couplings and finally derive the corresponding
one-loop, order $\alpha_s$, corrections to the Higgs bosons partial decay
widths into quarks.


title: b -> s gamma in a calculable model of Electroweak Symmetry Breaking

abstract:
  In a recently proposed extension of the Standard Model with a compact extra
dimension of size R we compute the leading corrections, of relative order (m_t
R)^2, to the Branching Ratio B -> X_s gamma. For 1/R = 370 \pm 80 GeV, the
branching ratio is increased in a significant way relative to the SM, although
not al level of being inconsistent with present measurements.


title: Unintegrated generalised parton distributions

abstract:
  We show how the generalised (or skewed) parton distributions of the proton,
H(x, xi; k_t^2, mu^2), unintegrated over the partonic transverse momenta, can
be calculated from the known conventional parton distributions, q(x, mu^2) and
g(x, mu^2), for small values of the skewedness parameter xi. We demonstrate the
procedure by numerically evaluating the skewed unintegrated gluon. We also
provide a simple approximate phenomenological form of the distribution, which
may be used to make more rapid predictions of observables.


title: Cornering (3+1) sterile neutrino schemes

abstract:
  Using the most recent atmospheric neutrino data, as well as short-baseline,
long-baseline and tritium $\beta$-decay data we show that the joint
interpretation of the LSND, solar and atmospheric neutrino anomalies in (3+1)
sterile neutrino schemes is severely disfavored, in contrast to the
theoretically favored (2+2) schemes.


title: Dark Matter Direct Searches and the Anomalous Magnetic Moment of Muon

abstract:
  In the framework of the Constrained Minimal Supersymmetric Standard Model
(CMSSM) we discuss the impact of the recent experimental information,
especially from E821 Brookhaven experiment on $g_{\mu}-2$ along with the light
Higgs boson mass bound from LEP, to the Dark Matter direct searches. Imposing
these experimental bounds, the maximum value of the spin-independent
neutralino-nucleon cross section turns out to be of the order of $10^{-8}$ pb
for large values of $\tan\beta$ and low $M_{1/2}, m_0$. The effect of the
recent experimental bounds is to decrease the maximum value of the cross
section by about an order of magnitude, demanding the analogous sensitivity
from the direct Dark Matter detection experiments.


title:
The Process \gamma^{*}_L+ q \to q\bar{q}g + q: Real Corrections to the
  Virtual Photon Impact Factor

abstract:
  We calculate, for the longitudinally polarized virtual photon, the cross
section of the process \gamma^{*}+q\to (q\bar{q}g)+q at high energies with a
large rapidity gap between the fragmentation system q\bar{q}g and the other
quark. This process provides the real corrections of the virtual photon impact
factor in the next-to leading order. Evidence is given for the appearance of a
new q\bar{q}g Fock-component of the photon state.


title: Recent Progress in Leptogenesis

abstract:
  After recalling the general virtues of leptogenesis we compare two
realizations, Affleck-Dine leptogenesis and thermal leptogenesis, which
generically lead to different predictions for neutrino masses. Finally, we
describe the progress towards a full quantum mechanical description of the
basic non-equilibrium process of leptogenesis beyond the approximations
involved in Boltzmann's equations.


title:
Pion Pair Production with Higher Order Radiative Corrections in Low
  Energy e+e- Collisions

abstract:
  The complete one-loop QED initial state, final state and initial--final state
interference corrections to the process e+e- -> pi+pi- are presented. Analytic
formulae are given for the virtual and for the real photon corrections. The
total cross section, the pion angular distribution and the pi+pi- invariant
mass distribution are investigated in the regime of experimentally realistic
kinematical cuts. It is shown that in addition to the full one-loop corrections
also two-loop initial state corrections and even the resummation of higher
order soft photon logarithms can be necessary if at least per cent accuracy is
required. For the data analysis we focus on an inclusive treatment of all
photons. The theoretical error concerning our treatment of radiative
corrections is then estimated to be less than 2 per mille for both the
measurement of the total cross section and the pi+pi- invariant mass
distribution. In addition we discuss the model uncertainty due to the pion
substructure. Altogether the precision of the theoretical prediction matches
the requirements of low energy e+e- experiments like the ones going on at DAFNE
or VEPP-2M.


title: Goldstone bosons and solitons on the brane

abstract:
  In this work we compute the effective action describing the low-energy brane
Goldstone-boson dynamics. The Goldstone bosons or branons appear because the
brane spontaneously breaks the translational invariance along the extra
dimensions. We discuss the Higgs-like mechanism in which the Kaluza-Klein gauge
fields absorb the Goldstone bosons and acquire mass. We also present the
explicit form of the effective action describing the low-energy interactions
between the three-brane Goldstone bosons and the Standard Model fields. In
addition to the branons, two new kinds of states arise corresponding to
Skyrmion-like solutions and wrapped states. We study the main properties of
these states, their geometrical interpretation and the relations between them.


title: Phenomenological implications of neutrinos in extra dimensions

abstract:
  Standard Model singlet neutrinos propagating in extra dimensions induce small
Dirac neutrino masses. While it seems rather unlikely that their Kaluza-Klein
excitations directly participate in the observed neutrino oscillations, their
virtual exchange may lead to detectable signatures in future neutrino
experiments and in rare charged lepton processes. We show how these effects can
be described by specific dimension-six effective operators and discuss their
experimental signals.


title:
Spin Transfers for Baryon Production in Polarized pp Collisions at
  RHIC-BNL

abstract:
  We consider the inclusive production of longitudinally polarized baryons in
${\vec p}p$ collisions at RHIC-BNL, with one longitudinally polarized proton.
We study the spin transfer between the initial proton and the produced baryon
as a function of its rapidity and we elucidate its sensitivity to the quark
helicity distributions of the proton and to the polarized fragmentation
functions of the quark into the baryon. We make predictions using an SU(6)
quark spectator model and a perturbative QCD (pQCD) based model. We discuss
these different predictions, and what can be learned from them, in view of the
forthcoming experiments at RHIC-BNL.


title: Constructing Parton Convolution in Effective Field Theory

abstract:
  Parton convolution models have been used extensively in describing the sea
quarks in the nucleon and explaining quark distributions in nuclei (the EMC
effect). From effective field theory point of view, we construct the parton
convolution formalism which has been the underlying conception of all
convolution models. We explain the significance of scheme and scale dependence
of the auxiliary quantities such as the pion distributions in a nucleon. As an
application, we calculate the complete leading nonanalytic chiral contribution
to the isovector component of the nucleon sea.


title:
New physics signatures at a Linear Collider: model-independent analysis
  from `conventional' polarized observables

abstract:
  We discuss four-fermion contact-interaction searches in the processes
e^+e^-\to\mu^+\mu^-, c{\bar c} and b{\bar b} at a future e^+e^- Linear Collider
with c.m. energy \sqrt{s}=0.5 TeV and with both beams longitudinally polarized.
Our analysis is based on the measurements of familiar polarized observables
such as the total cross section and the forward-backward/left-right
asymmetries, and accounts for the general set of contact interaction couplings
as independent, non-zero, parameters thus avoiding simplifying,
model-dependent, assumptions. We derive the corresponding model-independent
constraints on the above-mentioned coupling constants, and evaluate the
corresponding reach at the Linear Collider, emphasizing the role of beam
polarization. We compare the results with a model-dependent procedure where
only one coupling is varied at a time.


title: Termination of the Phase of Quintessence by Gravitational Back-Reaction

abstract:
  We study the effects of gravitational back-reaction in models of
Quintessence. The effective energy-momentum tensor with which cosmological
fluctuations back-react on the background metric will in some cases lead to a
termination of the phase of acceleration. The fluctuations we make use of are
the perturbations in our present Universe. Their amplitude is normalized by
recent measurements of anisotropies in the cosmic microwave background, their
slope is taken to be either scale-invariant, or characterized by a slightly
blue tilt. In the latter case, we find that the back-reaction effect of
fluctuations whose present wavelength is smaller than the Hubble radius but
which are stretched beyond the Hubble radius by the accelerated expansion
during the era of Quintessence domination can become large. Since the
back-reaction effects of these modes oppose the acceleration, back-reaction
will lead to a truncation of the period of Quintessence domination. This result
impacts on the recent discussions of the potential incompatibility between
string theory and Quintessence.


title: Neutrinoless double beta decay, solar neutrinos and mass scales

abstract:
  We obtain bounds for the neutrino masses by combining atmospheric and solar
neutrino data with the phenomenology of neutrinoless double beta decay where
hypothetical values of |< m>| are envisaged from future
0\nu\beta\beta-experiments. Different solutions for the solar neutrino data are
considered. For the Large-Mixing-Angle solution, a bound |< m>| \leq 0.01 eV
would strongly disfavour an inverted hierarchy of the neutrino masses.


title:
$\rho$ parameter constraints on radion phenomenology and a lower bound
  on Higgs mass

abstract:
  In this paper we determine the contribution of a light stabilized radion to
the weak isospin violating $\rho$ parameter by using an ultraviolet momentum
cut off as the regulator. The LEP1 bound on $\rho^{new}$ is then used to derive
constraints on the radion mass $\mphi$ and its vev $\vphi$. Finally by using
the beta function of the higgs self coupling we have determined a lower bound
on the higgs mass from the rho parameter constraints on $\mphi$ and $\vphi$.
Our results show that for $\mphi <$ 600 GeV the rho parameter bound on $m_h$ is
stronger than the present direct bound from LEPII.


title: B -> phi K decays in perturbative QCD approach

abstract:
  We calculate the branching ratios and CP asymmetries of the $B\to \phi K$
decays using perturbative QCD approach, which includes $k_T$ and threshold
resummations. Our results of branching ratios are consistent with the
experimental data and larger than those obtained from the naive factorization
assumption and the QCD-improved factorization approach.


title: A Bridge between CP violation at Low Energies and Leptogenesis

abstract:
  We discuss the possibility of relating the size and sign of the observed
baryon asymmetry of the universe to CP violation observable at low energies, in
a framework where the observed baryon asymmetry is produced by leptogenesis
through the out of the equilibrium decay of heavy Majorana neutrinos. We
identify the CP violating phases entering in leptogenesis as well as those
relevant for CP violation at low energies in the minimal seesaw model. We show
that although in general there is no relation between these two sets of phases,
there are specific frameworks in which such a connection may be established and
we give a specific grand unification inspired example where such a connection
does exist. We construct weak-basis invariants related to CP violation
responsible for leptogenesis, as well as those relevant for CP violation at low
energies.


title: Perturbative QCD analysis of $B \to \phi K$ decays and Power counting

abstract:
  We investigate exclusive nonleptonic $B$ meson decays $B\to\phi K$ in
perturbative QCD formalism. It is shown that the end-point (logarithmic and
linear) singularities in decay amplitudes do not exist, after $k_T$ and
threshold resummations are included. Power counting for emission and
annihilation topologies of diagrams, including both factorizable and
nonfactorizable ones, is discussed with Sudakov effects taken into account. Our
predictions for the branching ratios $B(B\to\phi K)\sim 10 \times 10^{-6}$ are
larger than those ($\sim 4 \times 10^{-6}$) from the factorization approach
because of dynamical enhancement of penguin contributions. Whether this
enhancement is essential for penguin-dominated modes can be justified by
experimental data.


title: Photons, neutrinos and optical activity

abstract:
  We compute the one-loop helicity amplitudes for low-energy
$\nu\gamma\to\nu\gamma$ scattering and its crossed channels in the standard
model with massless neutrinos. In the center of mass, with $\sqrt{s} =
2\omega\ll 2m_e$, the cross sections for these $2\to 2$ channels grow roughly
as $\omega^6$. The scattered photons in the elastic channel are circularly
polarized and the net value of the polarization is non-zero. We also present a
discussion of the optical activity of a sea of neutrinos and estimate the
values of its index of refraction and rotary power.


title: Neutrino-neutrino and neutrino-matter helicity flip interactions

abstract:
  Taking into account that neutrinos are massive particles and that they are
produced mainly as states of negative helicity, we show that the neutral and
charged current interactions change these neutrinos into transversally
polarized states. This implies a considerable reduction of the neutrino flux
when propagating through ordinary matter (electrons, protons and neutrons). The
same happens when neutrinos propagate through the sea of relic neutrinos if
these neutrinos are degenerate fermions. However, in this case the change of
helicity depends on the value of the neutrino--anti-neutrino asymmetry.


title: A generating functional for ultrasoft amplitudes in hot QCD

abstract:
  The effective amplitudes for gluon momentum p<<gT in hot QCD exhibit damping
as a result of collisions. The whole set of n-point amplitudes is shown to be
generated from one functional K(x,y;A), in addition to the induced current
j(x;A).


title: Muon g-2 and Minimal Supersymmetric Standard Model

abstract:
  The supersymmetric contribution to the muon g-2 is studied in light of the
finalization of the LEP electroweak precision data. The recent precise
measurement of the muon g-2 of E821 experiment is explained well by the
relatively light chargino and sleptons. We find that such the MSSM parameter
space is also favored from the electroweak precision data, in which the fit to
the data is better than that of the SM (\Delta \chi^2_{min} \sim -2), if the
lighter chargino has a mixed higgsino-wino character (\mu/M_2 \sim 1). The
models with light gauginos (\mu/M_2 > 10) or light higgsinos (\mu/M_2 < 0.1)
also show the better fit over the SM, but the improvement is marginal as
compared to the case of the mixed higgsino-wino case (\mu/M_2 \sim 1).


title: Inconsistencies in Models for RHIC and LHC

abstract:
  The interpretation of experimental results at RHIC and in the future also at
LHC requires very reliable and realistic models.
  Considerable effort has been devoted to the development of such models during
the past decade, many of them being heavily used in order to analyze data.
  It is the purpose of this paper to point out serious inconsistencies in the
above-mentioned approaches.
  We will demonstrate that requiring theoretical self-consistency reduces the
freedom in modeling high energy nuclear scattering enormously.
  We will introduce a fully self-consistent formulation of the
multiple-scattering scheme in the framework of a Gribov-Regge type effective
theory.
  In addition, we develop new computational techniques which allow for the
first time a satisfactory solution of the problem in the sense that
calculations of observable quantities can be done strictly within a
self-consistent formalism.


title: On the Evolution of Abelian-Higgs String Networks

abstract:
  We study the evolution of Abelian-Higgs string networks in large-scale
numerical simulations in both a static and expanding background. We measure the
properties of the network by tracing the motion of the string cores, for the
first time estimating the rms velocity of the strings and the invariant string
length, that is, the true network energy density. These results are compared
with a velocity-dependent one scale model for cosmic string network evolution.
This incorporates the contributions of loop production, massive radiation and
friction to the energy loss processes that are required for scaling evolution.
We use this analysis as a basis for discussing the relative importance of these
mechanisms for the evolution of the network. We find that the loop distribution
statistics in the simulations are consistent with the long-time scaling of the
network being dominated by loop production. Making justifiable extrapolations
to cosmological scales, these results appear to be consistent with the standard
picture of local string network evolution in which loop production and
gravitational radiation are the dominant decay mechanisms.


title:
Low x double $ln^2(1/x)$ resummation effects at the sum rules for
  nucleon structure function $g_1$

abstract:
  We have estimated the contributions to the moments of polarized nucleon
structure function $g_1(x,Q^2)$ coming from the region of the very low x
($10^{-5}<x$). Our approach uses the nucleon structure function extrapolated to
the region of low x by the means of the double $ln^2(1/x)$ resummation. The
$Q^2$ evolution of $g_1$ was described by the unified evolution equations
incorporating both the leading order Altarelli-Parisi evolution at large and
moderate x, and the double $ln^2(1/x)$ resummation at small x. The moments were
obtained by integrating out the extrapolated nucleon structure function in the
region $10^{-5}<x<1$.


title: Numerical Evaluation of Harmonic Polylogarithms

abstract:
  Harmonic polylogarithms $\H(\vec{a};x)$, a generalization of Nielsen's
polylogarithms ${S}_{n,p}(x)$, appear frequently in analytic calculations of
radiative corrections in quantum field theory. We present an algorithm for the
numerical evaluation of harmonic polylogarithms of arbitrary real argument.
This algorithm is implemented into a {\tt FORTRAN} subroutine {\tt hplog} to
compute harmonic polylogarithms up to weight 4.


title:
Baryogenesis via Density Fluctuations with a Second Order Electroweak
  Phase Transition

abstract:
  We consider the presence of cosmic string induced density fluctuations in the
universe at temperatures below the electroweak phase transition temperature.
Resulting temperature fluctuations can restore the electroweak symmetry
locally, depending on the amplitude of fluctuations and the background
temperature. The symmetry will be spontaneously broken again in a given
fluctuation region as the temperature drops there (for fluctuations with length
scales smaller than the horizon), resulting in the production of baryon
asymmetry. The time scale of the transition will be governed by the wavelength
of fluctuation and, hence, can be much smaller than the Hubble time. This leads
to strong enhancement in the production of baryon asymmetry for a second order
electroweak phase transition as compared to the case when transition happens
due to the cooling of the universe via expansion. For a two-Higgs extension of
the Standard Model (with appropriate CP violation), we show that one can get
the required baryon to entropy ratio if fluctuations propagate without getting
significantly damped. If fluctuations are damped rapidly, then a volume factor
suppresses the baryon production. Still, the short scale of the fluctuation
leads to enhancement of the baryon to entropy ratio by at least 3 - 4 orders of
magnitude compared to the conventional case of second order transition where
the cooling happens due to expansion of the universe.


title: Eta-eta' mixing in U(3) chiral perturbation theory

abstract:
  We investigate eta-eta' mixing in infrared regularized U(3) chiral
perturbation theory by calculating the eta and eta' masses up to one-loop
order. From this analysis it becomes obvious that even at leading order
eta-eta' mixing does not obey the usually assumed one-mixing angle scheme if
large N_c counting rules are not employed.


title: Flavor-Spin Symmetry Estimate of the Nucleon Tensor Charge

abstract:
  The axial vector and tensor charge, defined as the first moments of the
forward nucleon matrix elements of corresponding quark currents, are essential
for characterizing the spin structure of the nucleon. However, the transversity
distribution and thus the tensor charge decouple at leading twist in deep
inelastic scattering, making them hard to measure. Additionally, the
non-conservation of the tensor charge makes it difficult to predict. There are
no definitive theoretical predictions for the tensor charge, aside from several
model dependent calculations. We present a new approach that exploits the
approximate mass degeneracy of the light axial vector mesons ($a_1$(1260),
$b_1$(1235) and $h_1$(1170)) and uses pole dominance to calculate the tensor
charge. The result is simple in form. It 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.


title: Neutrino, Lepton, and Quark Masses in Supersymmetry

abstract:
  The recently proposed model of neutrino mass with no new physics beyond the
TeV energy scale is shown to admit a natural and realistic supersymmetric
realization, when combined with another recently proposed model of quark masses
in the context of a softly broken U(1) symmetry. Four Higgs doublets are
required, but two must have masses at the TeV scale. New characteristic
experimental predictions of this synthesis are discussed.


title:
Scaling in $\gamma^* p$ total cross sections, saturation and the gluon
  density

abstract:
  Including the new HERA data, the $\gamma^* p$ total cross section is analysed
in the generalized vector dominance/colour-dipole picture (GVD/CDP) that
contains scaling in $\eta = (Q^2 + m^2_0) / \Lambda^2 (W^2)$, where $\Lambda^2
(W^2)$ is an increasing function of $W^2$.
  At any $Q^2$, for $W^2 \to \infty$, the cross sections for virtual and real
photons become identical, $\sigma_{\gamma^* p} (W^2, Q^2) / \sigma_{\gamma p}
(W^2) \to 1$. The gluon density deduced from the colour-dipole cross section
fulfills the leading order DGLAP relationship. Evolution \`a la DGLAP breaks
down for $\eta \lsim 0.1$.


title: Anomalous Wtb Coupling in ep Collision

abstract:
  The potential of ep collision to prospect for anomalous Wtb vertex is
discussed from the single top quark production process $ep\to t\bar{\nu}+X$ for
TESLA+HERAp and CLIC+LHC energies. Sensitivities to anomalous couplings
$F_{2L}$ and $F_{2R}$, in the case of CLIC+LHC, are shown to be comparable with
LHC.


title: Higgs Decays to Muons in Weak Boson Fusion

abstract:
  We investigate the muonic decay of a light Higgs boson, produced in weak
boson fusion at future hadron colliders. We find that this decay mode would be
observable at the CERN LHC only with an unreasonably large amount of data,
while at a 200 TeV vLHC this process could be used to extract the muon Yukawa
coupling to about the 10% level, or better if significant improvements in
detector design can be achieved.


title: Finite-Width Effects in Top Quark Production at Hadron Colliders

abstract:
  Production cross sections for t\bar{t} and t\bar{t}j events at hadron
colliders are calculated, including finite width effects and off resonance
contributions for the entire decay chain, t --> bW --> b\ell\nu, for both top
quarks. Resulting background rates to Higgs search at the CERN LHC are updated
for inclusive H --> WW studies and for H --> \tau\tau and H --> WW decays in
weak boson fusion events. Finite width effects are large, increasing
t\bar{t}(j) rates by 20% or more, after typical cuts which are employed for
top-background rejection.


title: Theoretical Expectations for the Muon's Electric Dipole Moment

abstract:
  We examine the muon's electric dipole moment $\dmu$ from a variety of
theoretical perspectives. We point out that the reported deviation in the
muon's g-2 can be due partially or even entirely to a new physics contribution
to the muon's {\em electric} dipole moment. In fact, the recent g-2 measurement
provides the most stringent bound on $\dmu$ to date. This ambiguity could be
definitively resolved by the dedicated search for $\dmu$ recently proposed. We
then consider both model-independent and supersymmetric frameworks. Under the
assumptions of scalar degeneracy, proportionality, and flavor conservation, the
theoretical expectations for $\dmu$ in supersymmetry fall just below the
proposed sensitivity. However, non-degeneracy can give an order of magnitude
enhancement, and lepton flavor violation can lead to $\dmu$ of order $10^{-22}$
e cm, two orders of magnitude above the sensitivity of the $\dmu$ experiment.
We present compact expressions for leptonic dipole moments and lepton flavor
violating amplitudes. We also derive new limits on the amount of flavor
violation allowed and demonstrate that approximations previously used to obtain
such limits are highly inaccurate in much of parameter space.


title:
Comment on ``Remarks on flavor-neutrino propagators and oscillation
  formulae''

abstract:
  We comment on the paper ``Remarks on flavor-neutrino propagators and
oscillation formulae'' [Phys. Rev. D64, 013011 (2001)].
  We show that the conclusions presented in that paper do not apply to the
exact field theoretical oscillation formulae obtained in the BV formalism (for
three flavors) which are free from the dependence on arbitrary mass parameters,
account for CP violation and reduce to the usual quantum mechanical
(Pontecorvo) three flavor oscillation formulae in the relativistic limit.


title: Varieties of Dirac equation and flavors of leptons and quarks

abstract:
  I show that there exist twelve independent Dirac equations for spin 1/2
fermions. The Dirac fields that satisfy these equations can be grouped into six
pairs according to the way they transform under continuous space-time
transformations. These six pairs of Dirac equations correspond to the three
quark generations and the three lepton generations. The charged V-A currents
can be formed only from fields of the same pair. This property of the Dirac
fields implies that a quark or lepton may be transformed only into its partner
of the same generation via the charged-current weak interaction. According to
the properties of the charged-current weak interaction, I conclude that
different elementary fermion fields must satisfy different Dirac equations, and
there may not be more than twelve flavors of elementary fermions that are
already known.


title:
Strange form factors in the context of SAMPLE, HAPPEX, and A4
  experiments

abstract:
  The strange properties of the nucleon are investigated within the framework
of the SU(3) chiral quark-soliton model assuming isospin symmetry and applying
the symmetry conserving SU(3) quantization. We present the form factors
$G^0_{E,M}(Q^2)$, $G^Z_M(Q^2)$ and the electric and magnetic strange form
factors $G^s_{E,M}(Q^2)$ incorporating pion and kaon asymptotics. The results
show a fairly good agreement with the recent experimental data from the SAMPLE
and HAPPEX collaborations. We also present predictions for future measurements
including the A4 experiment at MAMI (Mainz).


title: Solving the Solar Neutrino Puzzle with KamLAND and Solar Data

abstract:
  We study what will be learnt about the solar neutrino puzzle and solar
neutrino oscillations once the data from the KamLAND reactor neutrino
experiment (soon to become available) are combined with those from the current
solar neutrino experiments. We find that, in agreement with previous estimates,
if the solution to the solar neutrino puzzle falls on the LMA region, KamLAND
should be able to ``pin-point'' the right solution with unprecedented accuracy
after a few years of data taking. Furthermore, the light side ($\theta<\pi/4$)
can be separated from the dark side ($\theta>\pi/4$) at the 95% confidence
level (CL) for most of the LMA region allowed by the current data at the 99%
CL, while the addition of the KamLAND data need not improve our ability to
limit a sterile component in ``solar'' oscillations. If KamLAND does not see an
oscillation signal, the solar data would point to the LOW/VAC regions, while
the SMA region would still lurk at the two sigma CL, meaning we would probably
have to wait for Borexino data in order to finally piece the solar neutrino
puzzle.


title: On the longitudinal contributions to hadronic tau decay

abstract:
  A number of recent determinations of $m_s$ using hadronic $\tau$ decay data
involve inclusive analyses based on the so-called $(k,0)$ spectral weights. We
show here that the OPE representations of the longitudinal contributions
appearing in these analyses, which are already known to be poorly converging,
have in addition an unphysical $k$ dependence which produces a significant
unphysical decrease in $m_s$ with increasing $k$. We also show how, using
additional sum rule constraints, the decay constants of the excited resonances
in the strange scalar and pseudoscalar channels may be determined, allowing one
to evaluate the longitudinal spectral contributions to the $(k,0)$ sum rules.
Taking into account the very-accurately known $\pi$ and $K$ pole contributions,
we find that longitudinal contributions can be determined with an accuracy at
the few % level, and hence reliably subtracted, leaving an analysis for $m_s$
involving the sum of longitudinal and transverse contributions, for which the
OPE representation is much better converged.


title:
The Use of Analyticity in the $\pi\pi$ and $K\bar K$ Coupled Channel
  System

abstract:
  Studies on the IJ=00 $\pi\pi$ and $K\bar K$ coupled--channel system are made
using newly derived dispersion relations between the phase shifts and poles and
cuts. It is found that the $\sigma$ resonance must be introduced to explain the
experimental phase shifts, after evaluating the cut contribution. The effects
of nearby branch point singularities to the determination of the $f_0(980)$
resonance are also carefully clarified.


title: Analysis of $B_{s} \to KK$ decays in the PQCD

abstract:
  We study $B_{s}\to KK$ decays in the framework of the PQCD. We show that the
branching ratios of $B_{s}\to (K^+ K^-, K^0 \bar{K}^0)$ are about $(22.43,
25.78) \times 10^{-6}$ for $\phi_{3}(\gamma)\simeq72^0$, which are consistent
with the model-independent estimations. We find that the typical scale of the
decays is near 1.7 GeV. We also point out that the induced strong phase
$\delta$ is around $207^0$ so that the direct CP asymmetry of $B_{s}\to K^+K^-$
could reach 15%.


title:
Fermion Mass Hierarchy in the Grand Unified Theory on $S_1/(Z_2 \times
  Z_2')$ Orbifold

abstract:
  We suggest a simple grand unified theory where the fifth dimensional
coordinate is compactified on an $S_1/(Z_2 \times Z_2')$ orbifold. This model
is based on the supersymmetric flipped $SU(5) \times U(1)$ grand unified
theory, which can realize not only the triplet-doublet splitting but also the
natural fermion mass hierarchies. The triplet-doublet splitting is realized by
$S_1/(Z_2 \times Z_2')$ orbifolding, which also reduces the gauge group as
$SU(5) \times U(1) \to SU(3)_c \times SU(2)_L \times U(1)_Z \times U(1)_X$. The
suitable fermion mass hierarchies are generated by integrating out extra three
sets of vector-like heavy fields which can propagate in five dimensions. The
radiative corrections to the large Yukawa coupling of right-handed neutrinos
can reduce the gauge group to $SU(3)_c \times SU(2)_L \times U(1)_Y$.


title: Moving boundary effects in Quark Gluon Plasma

abstract:
  We analyze the known moving boundary effects in plasma and briefly review a
mechanism for particle acceleration through a plasma front. We then show how
this mechanism may affect particles crossing the boundary of an expanding quark
gluon plasma.


title: The Applicability of PQCD and NLO Power Corrections for Pion Form Factor

abstract:
  In many years ago, Isgur and Llewellyn Smith addressed that PQCD is
inapplicable to exclusive processes, such as the pion form factor.The main
problem is that the asymptotic of PQCD is only about one fourth of the
experimental value. We reexamine this PQCD deep problem. By including NLO power
corrections to the pion form factor, we may arrive at a perturbative
explanation for the data. The key realization is that we need to interprete
that the strong interaction coupling constant involved in the PQCD result
should be taken as an effective coupling constant under nonperturbative QCD
vaccum. This implies that one can equally identify the relevant scale for the
effective coupling constant as the factorization scale about 1 GeV. We also
find that the average momentum fraction variable locates about 0.5, which is in
favor of the asymptotic pion wave function. By employing photon-pion form
factor with NLO power corrections to factorize out the nonperturbative effects
involved in the effective coupling constant, we can extract an effective
running coupling constant, which represents an effective coupling involving in
the hard scattering subprocesses. The difference between the effective running
coupling constant and the usual perturbative running coupling constant
($\Lambda_{QCD}=0.3$ GeV) is very small for $Q^2> 1 GeV^2$. The effective
running coupling constant $\alpha_s/\pi$ is smaller than 0.2 for $Q^2>1 GeV^2$.
  This directly showes that PQCD is applicable to exclusive processes at energy
$Q^2> 1 GeV^2$. In summary, with NLO power corrections, PQCD can completely
explain the $Q^2$ spectrum of pion form factor.


title:
Production of Heavy Quarks in Deep-Inelastic Lepton-Hadron Scattering
  scattering

abstract:
  We will give a review of the computation of exact next-to-leading order
corrections to heavy quark production in deep inelastic lepton-hadron
scattering and discuss the progress made in this field over the past ten years.
In this approach, hereafter called EXACT, where the heavy quark mass is taken
to be of the same order of magnitude as the other large scales in the process,
one can apply perturbation theory in all orders of the strong coupling constant
alpha_s. The results are compared with another approach, called the variable
flavor number scheme (VFNS), where the heavy quark is also treated as a
massless quark. It turns out that the differences between the two approaches
are very small provided both of them are carried out up to
next-to-next-to-leading order.


title:
Parton densities and structure functions at next-to-next-to-leading
  order and beyond

abstract:
  We summarize recent results on the evolution of unpolarized parton densities
and deep-inelastic structure functions in massless perturbative QCD. Due to
last year's extension of the integer-moment calculations of the three-loop
splitting functions, the NNLO evolution of the parton distributions can now be
performed reliably at momentum fractions x >= 10^-4, facilitating a
considerably improved theoretical accuracy of their extraction from data on
deep-inelastic scattering. The NNLO corrections are not dominated, at relevant
values of x, by their leading small-x terms. At large x the splitting-function
series converges very rapidly, hence, employing results on the three-loop
coefficient functions, the structure functions can be analysed at N^3LO for x >
10^-2. The resulting values for alpha_s do not significantly change beyond
NNLO, their renormalization scale dependence reaches about +-1% at N^3LO.


title:
Evidence for a two scale Infrared NPQCD dynamics from Pade couplant
  structures

abstract:
  We report our finding of a two scale cut off structure in the infrared
nonperturbative dynamics of Pade couplant QCD, in the flavor states $N_{f} \le
8$. We argue that these two NPQCD momentum scales $Q_{c}(Y_{1})$ and
$Q_{c}(Y_{2})$ can be identified as the scales of onset of chiral symmetry
breaking and quark confinement in QCD, and as the cut off boundaries of a
strongly interacting infrared quark gluon phase of Quantum Chromodynamics,
intermediate between the hadronic phase of QCD and the weakly coupled
perturbative QCD regime. We investigated the pattern of variation with flavor
number $N_{f} \le 8$, of these domain boundaries of the intermediate
nonperturbative infrared QCD, and found that the two scales are correlated,
with a correlation factor $Q_{c}(Y_{2})/Q_{c}(Y_{1})$ that rises to a peak at
$N_{f} = 2$ from $N_{f} = 0$, but falls off rapidly to zero for $4 \le N_{f}
\le 8$. We concluded firmly that dynamical chiral symmetry breaking and quark
confinement while being two distinct QCD phenomena caused by two independent
component QCD forces $Y_{1}$ and $Y_{2}$, are nevertheless closely related
phenomena of infrared nonperturbative QCD dynamics. Their correlation leads us
to a finding that quark confinement is most favored in the $N_{f} = 2$ flavor
state of QCD, but becomes rapidly less probable for $N_{f} \geq 4$, this
finding being exactly as one observes in nature.


title:
The magnetic moments of 'Lambda_b' and 'Lambda_c' baryons in light cone
  QCD sum rules

abstract:
  Using the most general form of the interpolating currents of heavy baryons,
the magnetic moments of heavy baryons "Lambda_Q (Q=b,c)" are calculated in
framework of the light cone QCD sum rules. A comparison of our results on
magnetic moments with the existing theoretical results calculated in various
other frameworks are presented.


title:
Impact of the three-loop corrections on the QCD analysis of the
  deep-inelastic-scattering data

abstract:
  We perform the analysis of the existing inclusive deep inelastic scattering
(DIS) data within NNLO QCD approximation. The parton distributions functions
(PDFs) and the value of strong coupling constant
$\alpha_{s}(M_Z)=0.1143\pm0.0013 (exp)$ are obtained. The sensitivity of the
PDFs to the uncertainty in the value of the NNLO corrections to the splitting
functions is analyzed. It is shown that the PDFs errors due to this uncertainty
is generally less than the experimental uncertainty in PDFs through the region
of $x$ spanned by the existing DIS data.


title: Power corrections to the event shape in $e^+e^-$ annihilation

abstract:
  We study power corrections to the event shapes in $\e^+\e^--$annihilation in
the two jets kinematical region, $e\ll 1$. We argue that for $e \sim
\Lambda_{QCD}/Q$ all power corrections of the form $1/\lr{Qe}^n$ have to be
taken into account for an arbitrary $n$. This is achieved by introducing a new
universal distribution, the shape function, which describes the energy flow in
the final state. The event shape differential distributions are given by a
convolution of the shape function with perturbatively resummed cross-sections.
Choosing a physically motivated ansatz for the shape function, we observe a
good agreement of our predictions with available data on the differential
thrust, $C$-parameter and heavy-jet mass distributions and their first few
moments.


title: Isospin violation in pion-kaon scattering

abstract:
  We consider strong and electromagnetic isospin violation in near-threshold
pion-kaon scattering. At tree level, such effects are small for all physical
channels. We work out the complete one-loop corrections to the process pi^- K^+
-> pi^0 K^0. They come out rather small. We also show that the corresponding
radiative cross section is highly suppressed at threshold.


title:
Renormalization in Self-Consistent Approximations schemes at Finite
  Temperature I: Theory

abstract:
  Within finite temperature field theory, we show that truncated
non-perturbative self-consistent Dyson resummation schemes can be renormalized
with local counter-terms defined at the vacuum level. The requirements are that
the underlying theory is renormalizable and that the self-consistent scheme
follows Baym''s $\Phi$-derivable concept. The scheme generates both, the
renormalized self-consistent equations of motion and the closed equations for
the infinite set of counter terms. At the same time the corresponding
2PI-generating functional and the thermodynamical potential can be
renormalized, in consistency with the equations of motion. This guarantees the
standard $\Phi$-derivable properties like thermodynamic consistency and exact
conservation laws also for the renormalized approximation schemes to hold. The
proof uses the techniques of BPHZ-renormalization to cope with the explicit and
the hidden overlapping vacuum divergences.


title: Non-local symmetry breaking in Kaluza-Klein theories

abstract:
  Scherk-Schwarz gauge symmetry breaking of a D-dimensional field theory model
compactified on a circle is analyzed. It is explicitly shown that forbidden
couplings in the unbroken theory appear in the one-loop effective action only
in a non-local way, implying that they are finite at all orders in perturbation
theory. This result can be understood as a consequence of the local gauge
symmetry, but it holds true also in the global limit.


title:
Comparison of the fits to data on polarised structure functions and spin
  asymmetries

abstract:
  In order to obtain polarised parton densities we have made next to leading
order QCD fit using experimental data on deep inelastic structure functions on
nucleons. This fit is compared with the updated fit to coresponding spin
asymmetries. We get very similar results for all fits also for different data
samples. It seems that only polarised parton densities for non-strange quarks
$\Delta u$ and $\Delta d$ are relatively well determined from the present deep
inelastic experiments. Inegrated gluon contribution at $Q^{2}=1 {\rm GeV^{2}}$
is, as in our previous fits, very small.


title: Light Unstable Sterile Neutrino

abstract:
  The three massless active (doublet) neutrinos may mix with two heavy and one
\underline {light} sterile (singlet) neutrinos so that the induced masses and
mixings among the former are able to explain the present data on atmospheric
and solar neutrino oscillations. If the LSND result is also to be explained,
one active neutrino mass eigenstate must mix with the light sterile neutrino. A
specific model is proposed with the spontaneous and soft explicit breaking of a
new global $U(1)_S$ symmetry so that a sterile neutrino will decay into an
active antineutrino and a nearly massless pseudo-Majoron.


title: Neutrino Anomalies in Gauge Mediated Model with Trilinear R violation

abstract:
  The structure of neutrino masses and mixing resulting from trilinear $R$
violating interactions is studied in the presence of the gauge mediated
supersymmetry breaking. Neutrino masses arise in this model at tree level
through the RG-induced vacuum expectation values of the sneutrinos and also
through direct contribution at 1-loop. The relative importance of these
contributions is determined by the values of the strong and weak coupling
constants. In case of purely $\lambda'$ couplings, the tree contribution
dominates over the 1-loop diagram. In this case, one simultaneously obtains
atmospheric neutrino oscillations and quasi-vacuum oscillations of the solar
neutrinos if all the $\l'$ couplings are assumed to be of similar magnitudes.
If R parity violation arises from the trilinear $\l$ couplings, then the loop
induced contribution dominates over the tree level. One cannot simultaneously
explain the solar and atmospheric deficit in this case if all the $\l$
couplings are of similar magnitude. This however becomes possible with
hierarchical $\l$ and we give a specific example of this.


title: Semileptonic decays of double heavy baryons

abstract:
  We study the semileptonic decays of the lowest lying double heavy baryons
using the relativistic three-quark model. We do not employ a heavy quark mass
expansion but keep the masses of the heavy quarks and baryons finite. We
calculate all relevant form factors and decay rates.


title: Understanding the penguin amplitude in $B \to \phi K$ decays

abstract:
  We calculate branching ratios for pure penguin decay modes, $B\to \phi K$
decays using perturbative QCD approach. Our results of branching ratios are
consistent with the experimental data and larger than those obtained from the
naive factorization assumption and the QCD-improved factorization approach.
This is due to a dynamical penguin enhancement in perturbative QCD approach.


title: Unifying approach to hard diffraction

abstract:
  We find a consistency between two different approaches of hard diffraction,
namely the QCD dipole model and the Soft Colour Interaction approach. A
theoretical interpretation in terms of S-Matrix and perturbative QCD properties
in the small $x_{Bj}$ regime is proposed.


title: The photoproduction of vector mesons

abstract:
  At high energy, the photoproduction or electroproduction of Vector Mesons
allow to prepare a beam of quark-antiquark pairs of a given flavor. At high
momentum transfer, the study of the scattering of these pairs on a nucleon
opens up an original window on the quark-gluon structure of hadronic matter,
which may eventually shed light on its gluonic content, on correlations between
quarks and on the van der Walls part of the interaction between hadrons.


title: Top quark mass determination near t\bar{t} threshold at lepton colliders

abstract:
  Future e^+ e^- linear colliders will enable us to determine the top quark
mass with high accuracy from the measurement of the 1S peak position of
(remnant of) toponium. The estimated statistical error in this measurement is
about 50 MeV with integrated luminosity of 30 ${\rm fb^{-1}}$. We calculate
${\cal O}(\alpha_s^5 m)$ corrections to the quarkonium 1S energy spectrum in
the large-$\beta_0$ approximation to reduce theoretical uncertainties below the
corresponding experimental error. We discuss the significance of the ${\cal
O}(\alpha_s^5 m)$ corrections and estimate theoretical uncertainties of our
prediction.


title: Relativistic covariance and the bound state wave function

abstract:
  We establish a relation between the solution of a relativistic bound state
equation in quantum mechanics and the field representation of a bound state
with the aid of creation and annihilation operators. We show that a bound
system can be represented by a gas of free constituents and a classical
effective field representing the countless quantum fluctuations generating the
binding potential. The distribution function of the internal momenta is given
by the projection of the free states on the solution of a relativistic bound
state equation in the rest frame of the bound system. In this approach Lorentz
covariance, mass-shell constraints and single particle normalizability of the
bound state function are simultaneously and explicitly satisfied. The
discussion is made for a two particle bound state and can be easily generalized
to the case of three or more particles.


title: Illuminating Dense Quark Matter

abstract:
  We imagine shining light on a lump of cold dense quark matter, in the CFL
phase and therefore a transparent insulator. We calculate the angles of
reflection and refraction, and the intensity of the reflected and refracted
light. Although the only potentially observable context for this phenomenon
(reflection of light from and refraction of light through an illuminated quark
star) is unlikely to be realized, our calculation casts new light on the old
idea that confinement makes the QCD vacuum behave as if filled with a
condensate of color-magnetic monopoles.

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


title: The Inflatino Problem in Supergravity Inflationary Models

abstract:
  We consider the potential problems due to the production of inflatinos and
gravitinos after inflation. Inflationary models with a single scale set by the
microwave background anisotropies have a low enough reheat temperature to avoid
problems with the thermal production of gravitinos. Moreover, the nonthermal
production of gravitinos has been shown to be sufficiently small if the sector
ultimately responsible for supersymmetry breaking is coupled only
gravitationally to the inflationary sector. Still, in some models, inflatinos
can be created during preheating with a substantial abundance. The main
contribution to the gravitino abundance may thus come from their decay into the
inflaton, or into its scalar partner, as well as from the inverse processes. We
show that this production needs to be strongly suppressed. This suppression can
be realized in the simplest scenarios which typically have a sufficiently high
inflationary scale.


title: A New Approach To The Hierarchy Problem

abstract:
  We argue that identifying the electroweak Higgs particle with the extra
components of the gauge field in $4+d$ dimensions provides a solution to the
hierarchy problem. The absence of ultraviolate quadratic divergences is due to
the fact that the Higgs mass is protected by an exact gauge symmetry at
energies beyond the cutoff. The idea is implemented within explicit models
which also provide a link between fermion chirality and electroweak symmetry
breaking in four dimensions.


title: Leptoquark Signals via $\nu $ interactions at Neutrino Factories

abstract:
  The accurate prediction of neutrino beam produced in muon decays and the
absence of opposite helicity contamination for a particular neutrino flavour
makes a future neutrino factory (NF) based on a muon storage ring (MSR), the
ideal place to look for the lepton flavour violating (LFV) effects. In this
paper, we address the contribution of mediating LFV leptoquarks (LQ) in $\nu
(\bar\nu)-{N}$ interactions leading to production of $\tau$'s and wrong sign
$\mu$'s at MSR and investigate the region where LQ interactions are significant
in the near-site and short baseline experiments.


title: Leptogenesis and Neutrinos at a TeV

abstract:
  We consider a model for leptogenesis in which all the relevant physics is
accessible in collider experiments. This requires a moderate extension of the
standard model which generates small neutrino masses via TeV scale right-handed
neutrinos. The necessary Sakharov criteria are satisfied in such a way that all
existing experimental constraints are satisfied. We demonstrate how the
requisite baryon to entropy ratio is generated, and discuss some possible
experimental signatures of the model.


title: Sneutrino Mass Measurements at e+e- Linear Colliders

abstract:
  It is generally accepted that experiments at an e+e- linear colliders will be
able to extract the masses of the selectron as well as the associated
sneutrinos with a precision of ~ 1% by determining the kinematic end points of
the energy spectrum of daughter electrons produced in their two body decays to
a lighter neutralino or chargino. Recently, it has been suggested that by
studying the energy dependence of the cross section near the production
threshold, this precision can be improved by an order of magnitude, assuming an
integrated luminosity of 100 fb^-1. It is further suggested that these
threshold scans also allow the masses of even the heavier second and third
generation sleptons and sneutrinos to be determined to better than 0.5%. We
re-examine the prospects for determining sneutrino masses. We find that the
cross sections for the second and third generation sneutrinos are too small for
a threshold scan to be useful. An additional complication arises because the
cross section for sneutrino pair to decay into any visible final state(s)
necessarily depends on an unknown branching fraction, so that the overall
normalization in unknown. This reduces the precision with which the sneutrino
mass can be extracted. We propose a different strategy to optimize the
extraction of m(\tilde{\nu}_\mu) and m(\tilde{\nu}_\tau) via the energy
dependence of the cross section. We find that even with an integrated
luminosity of 500 fb^-1, these can be determined with a precision no better
than several percent at the 90% CL. We also examine the measurement of
m(\tilde{\nu}_e) and show that it can be extracted with a precision of about
0.5% (0.2%) with an integrated luminosity of 120 fb^-1 (500 fb^-1).


title:
Photon Damping Caused by Electron-Positron Pair Production in a Strong
  Magnetic Field

abstract:
  Damping of an electromagnetic wave in a strong magnetic field is analyzed in
the kinematic region near the threshold of electron-positron pair production.
Damping of the electromagnetic field is shown to be noticeably nonexponential
in this region. The resulting width of the photon $\gamma \to e^+ e^-$ decay is
considerably smaller than previously known results.


title: Stau LSP and comparison with H^+(-) phenomenology

abstract:
  In supersymmetric models with explicit breaking of R-parity the lightest
supersymmetric particle (LSP) may be the lightest stau, $\stau_1$. Such a
scenario would provide a clear sign of R-parity violating SUSY, although its
phenomenology may resemble that of a charged Higgs boson, $H^\pm$. We discuss
various ways of distinguishing a LSP $\stau_1$ from $H^\pm$ at future
colliders, and address the case of $\stau_1$ mimicking the signal for $H^\pm$.
As an example we suggest that the recent L3 signal for $H^+H^-\to qq'qq'$ and
$H^+H^-\to qq'\tau\nu_{\tau}$ could be more easily explained by a LSP
$\stau_1$.


title:
Hadronic scattering amplitudes: medium-energy constraints on asymptotic
  behaviour

abstract:
  We consider several classes of analytic parametrisations of hadronic
scattering amplitudes, and compare their predictions to all available forward
data (p p, pbar p, pi p, K p, gamma p, gamma gamma, Sigma p). Although these
parametrisations are very close for sqrt(s) > 9 GeV, it turns out that they
differ markedly at low energy, where a universal pomeron term ~log^2(s) enables
one to extend the fit down to sqrt(s)=4 GeV.


title: The problem of neutrino masses in extensions of the Standard Model

abstract:
  We review the problem of neutrino masses and mixings in the context of Grand
Unified Theories. After a brief summary of the present experimental status of
neutrino physics, we describe how the see-saw mechanism can automatically
account for the large atmospheric mixing angle. We provide two specific
examples where this possibility is realized by means of a flavour symmetry. We
then review in some detail the various severe problems which plague minimal GUT
models (like the doublet-triplet splitting and proton-decay) and which force to
investigate the possibility of constructing more elaborate but realistic
models. We then show an example of a quasi-realistic SUSY SU(5) model which, by
exploiting the crucial presence of an abelian flavour symmetry, does not
require any fine-tuning and predicts a satisfactory phenomenology with respect
to coupling unification, fermion masses and mixings and bounds from proton
decay.


title: Neutrino cross-section measurement with neutrinos from muon decay

abstract:
  In this paper we stress the idea that new, more precise neutrino
cross-sections measurements at low energies will be necessary to improve the
results of future big neutrino detectors, which will be dominated by the
contribution of the systematic errors. The use of a muon beam instead of the
traditional pion beams is proposed. This choice allows the simultaneous
measurement of both, numu and nue interactions and the two helicities, in a
clean environment and with a precise knowledge of the beam flux. We show that
with approx 10^{15} mu's/year and a moderate mass detector (approx 100 tons)
placed close to the muon storage ring, precisions of the order of 10% in
sigma(nu) (E_nu bin size of 100 MeV) can be reached for neutrino energies below
2 GeV.


title:
Up and Down Quark Contributions to Spin Content of Lambda from
  Fragmentation

abstract:
  We check the $u$ and $d$ quark contributions to the spin content of the
$\Lambda$ by means of the $q\to\Lambda$ fragmentation and find that the $u$ and
$d$ quarks of the $\Lambda$ are likely positively polarized. The parton
distributions in the $\Lambda$ are given by a successful statistical model
which can reproduce and correlate a vast body of polarized and unpolarized
structure function and parton distribution data of the nucleon. With the
Gribov-Lipatov relation between the quark distributions and fragmentation
functions, the longitudinal spin transfer for the $\Lambda$ production in the
polarized charged lepton deep inelastic scattering (DIS) process and the
$\Lambda$-polarization in the neutrino (antineutrino) DIS process are
predicted. The available experimental data suggests that the $u$ and $d$ quark
contributions to the spin of the $\Lambda$ are positive. In addition, our
results provide a collateral evidence for the SU(3) symmetry breaking in
hyperon semileptonic decays of the octet baryons, which is very important for a
deeper understanding of the proton 'spin crisis'.


title:
Spatially Anisotropic Four-Dimensional Gauge Interactions, Planar
  Fermions and Magnetic Catalysis

abstract:
  We consider magnetic catalysis in a field-theoretic system of
(3+1)-dimensional Dirac fermions with anisotropic kinetic term. By placing the
system in a strong external magnetic field, we examine magnetically-induced
fermion mass generation. When the coupling anisotropy is strong, in which case
the fermions effectively localize on the plane, we find a significant
enhancement of the induced mass gap compared to the isotropic four-dimensional
case of quantum electrodynamics. As expected on purely dimensional grounds, the
mass and critical temperature scale with the square root of the magnetic field.
This phenomenon might be related to recent experimental findings on
magnetically-induced gaps at the nodes of d-wave superconducting gaps in
high-temperature cuprates.


title: Colour dipoles and virtual Compton scattering

abstract:
  An analysis of Deeply Virtual Compton Scattering (DVCS) is made within the
colour dipole model. We compare and contrast two models for the dipole
cross-section which have been successful in describing structure function data.
Both models agree with the available cross section data on DVCS from HERA. We
give predictions for various azimuthal angle asymmetries in HERA kinematics and
for the DVCS cross section in the THERA region.


title: Interaction of Reggeized Gluons in the Baxter-Sklyanin Representation

abstract:
  We investigate the Baxter equation for the Heisenberg spin model
corresponding to a generalized BFKL equation describing composite states of n
Reggeized gluons in the multi-color limit of QCD. The Sklyanin approach is used
to find an unitary transformation from the impact parameter representation to
the representation in which the wave function factorizes as a product of Baxter
functions and a pseudo-vacuum state. We show that the solution of the Baxter
equation is a meromorphic function with poles (lambda - i r)^{-(n-1)} (r= 0,
1,...) and that the intercept for the composite Reggeon states is expressed
through the behavior of the Baxter function around the pole at lambda = i . The
absence of pole singularities in the two complex dimensional lambda-plane for
the bilinear combination of holomorphic and anti-holomorphic Baxter functions
leads to the quantization of the integrals of motion because the holomorphic
energy should be the same for all independent Baxter functions.


title: Study of Semileptonic Decays $B^\pm \to \eta^{(\prime)} l \nu$

abstract:
  We study semileptonic decays $B^\pm \to \eta^{(\prime)} l \nu$, which are
suggested to be used to extract the hadronic form factors of $B$ meson decays
to $\eta(\eta^{\prime})$ and the angle of $\eta-\eta^{\prime}$ mixing. This
would be of great benefit to theoretical studies of $B$ nonleptonic decays
involving $\eta$ and $\eta^{\prime}$, and could lead to a reliable and
complementary determination of $V_{ub}$. The branching ratios are estimated to
be ${\cal B}(B^\pm \to\eta^{(\prime)} l \nu)=4.32 \pm 0.83 (2.10 \pm 0.40)
\times 10^{-5}$, which could be extensively studied experimentally at $BaBar$
and Belle.


title:
Color Transparency versus Quantum Coherence in Electroproduction of
  Vector Mesons off Nuclei

abstract:
  So far no theoretical tool for the comprehensive description of exclusive
electroproduction of vector mesons off nuclei at medium energies has been
developed. We suggest a light-cone QCD formalism which is valid at any energy
and incorporates formation effects (color transparency), the coherence length
and the gluon shadowing. At medium energies color transparency (CT) and the
onset of coherence length (CL) effects are not easily separated. Indeed,
although nuclear transparency measured by the HERMES experiment rises with Q^2,
it agrees with predictions of the vector dominance model (VDM) without any CT
effects. Our new results and observations are: (i) the good agreement with the
VDM found earlier is accidental and related to the specific correlation between
Q^2 and CL for HERMES kinematics; (ii) CT effects are much larger than have
been estimated earlier within the two channel approximation. They are even
stronger at low than at high energies and can be easily identified by HERMES or
at JLab; (iii) gluon shadowing which is important at high energies is
calculated and included; (iv) our parameter-free calculations explain well
available data for variation of nuclear transparency with virtuality and energy
of the photon; (v) predictions for electroproduction of \rho and \phi are
provided for future measurements at HERMES and JLab.


title: About the origins of the Supersymmetric Standard Model

abstract:
  Could one use supersymmetry to relate the fermions, constituants of matter,
with the bosons messengers of the interactions? This is, ideally, what a
symmetry between fermions and bosons would be expected to do.
  However many obstacles seemed, long ago, to prevent supersymmetry from
possibly being a fundamental symmetry of Nature. Which fermions and bosons
could be related? Is spontaneous supersymmetry breaking possible at all? If
yes, where is the corresponding spin-1/2 Goldstone fermion? Supersymmetric
theories also involve Majorana fermions, unknown in Nature. And how could we
define conserved quantum numbers like B and L, when these are carried by
fundamental (Dirac) fermions only, not by bosons?
  An early attempt to relate the photon with a ``neutrino'' led us to
R-invariance and to a new R quantum number carried by the supersymmetry
generator, but this ``neutrino'' had to be reinterpreted as a new particle, the
photino. We also had to introduce bosons carrying ``fermion numbers'' B and L,
which became the squarks and sleptons. This led to the Supersymmetric Standard
Model, involving SU(3) x SU(2) x U(1) gauge superfields interacting with chiral
quark and lepton superfields, and two doublet Higgs superfields responsible for
quark and lepton masses. R-parity, deeply related with B and L conservation
laws, appeared as a remnant of the original R-invariance, reduced to a discrete
symmetry so that the gravitino and gluinos can acquire masses. We also comment
about supersymmetry breaking.


title: Photon Propagation in Space-Time with a Compactified Spatial Dimension

abstract:
  The one-loop effects of vacuum polarization induced by untwisted fermions in
QED in a nonsimply connected space-time with topology $S^{1}\times R^{3}$ are
investigated. It is found that photon propagation in this system is
anisotropic, appearing several massive photon modes and a superluminal
transverse mode. For small compactification radius $a$, the superluminal
velocity increases logarithmically with $a$. At low energies the photon masses
lead to an effective confinement of the gauge fields into a (2+1)-dimensional
manifold transverse to the compactified direction. The system shows a
topologically induced directional superconductivity.


title: Scaling property and peculiar velocity of global monopoles

abstract:
  We investigate the scaling property of global monopoles in the expanding
universe. By directly solving the equations of motion for scalar fields, we
follow the time development of the number density of global monopoles in the
radiation dominated (RD) universe and the matter dominated (MD) universe. It is
confirmed that the global monopole network relaxes into the scaling regime and
the number per hubble volume is a constant irrespective of the cosmic time. The
number density $n(t)$ of global monopoles is given by $n(t) \simeq
(0.43\pm0.07) / t^{3}$ during the RD era and $n(t) \simeq (0.25\pm0.05) /
t^{3}$ during the MD era. We also examine the peculiar velocity $v$ of global
monopoles. For this purpose, we establish a method to measure the peculiar
velocity by use of only the local quantities of the scalar fields. It is found
that $v \sim (1.0 \pm 0.3)$ during the RD era and $v \sim (0.8 \pm 0.3)$ during
the MD era. By use of it, a more accurate analytic estimate for the number
density of global monopoles is obtained.


title: Telling three from four neutrinos at the Neutrino Factory

abstract:
  We upgrade the study of the physical reach of a Neutrino Factory considering
the possibility to distinguish a three (active) neutrino oscillation scenario
from the scenario in which a light sterile neutrino is also present. The
distinction is easily performed in the so--called 2+2 scheme, but also in the
more problematic 3+1 scheme it can be attained in some regions of the parameter
space. We also discuss the CP violating phase determination, showing that the
effects of a large phase in the three--neutrino theory cannot be reproduced in
a four--neutrino, CP conserving, model.


title: Higgs mass bounds in a Triplet Model

abstract:
  We perform a global fit to high energy precision electroweak data in a Higgs
model containing the usual isospin doublet plus a real isospin triplet. The
analysis is performed in terms of the oblique parameters S, T and U and we show
that the mass of the lightest Higgs boson can be as large as 2 TeV.


title: Two-loop Higgs mass in supersymmetric Kaluza-Klein theories

abstract:
  We perform an explicit two-loop computation of the Higgs mass in a
five-dimensional supersymmetric theory compactified on the orbifold S^1/Z_2,
with superpotential localized on a fixed-point brane and supersymmetry broken
in the bulk of the extra dimension by Scherk-Schwarz boundary conditions. At
one-loop, the Higgs mass is finite and proportional to 1/R^2, R being the
radius of the extra dimension. The two-loop corrections contain finite
proportional to 1/R^2 and linearly divergent Lambda/R terms, where Lambda is
the cutoff of the five-dimensional theory. The divergent terms are cancelled by
diagrams containing one-loop wave-function renormalization counterterms, i.e.
by linear threshold effects of Yukawa (and gauge) couplings, at the scale 1/R.
As a result there is no counterterm for the Higgs mass, which is finite and
calculable to the considered order.


title: B0bar decays to D(*)0 eta and D(*)0 eta'

abstract:
  We consider the hadronic B decays B0bar -> D0 eta, B0bar -> D*0 eta, B0bar ->
D0 eta', B0bar -> D*0 eta' in the framework of a quark-flavour basis and
factorization. The formalism allows to compute the decays to the eta meson and
to relate them to those of the eta'. Measuring the branching ratios of these
processes may shed light on the nature of the eta-eta' mixing. On the
experimental side, only upper limits on the branching ratios are known at
present.


title: Effects of periodic matter in kaon regeneration

abstract:
  We study the effects of periodic matter in kaon regeneration, motivated by
the possibility of parametric resonance in neutrino oscillations. The large
imaginary parts of the forward kaon-nucleon scattering amplitudes and the decay
width difference $\Delta\Gamma$ prevent a sizable enhancement of the $K_L\to
K_S$ transition probability. However, some interesting effects can be produced
using regenerators made of alternating layers of two different materials.
Despite the fact that the regenerator has a fixed length one can obtain
different values for the probability distribution of the $K_L$ decay into a
final state. Using a two-arm regenerator set up it is possible to measure the
imaginary parts of the $K^0(\bar{K}^0)$-nucleon scattering amplitudes in the
correlated decays of the $\phi$-resonance. Combining the data of the single-arm
regenerator experiments with direct and reverse orders of the matter layers in
the regenerator one can independently measure the CP violating parameter
$\delta$.


title: Model-independent search for the Abelian Z' boson and the LEP data

abstract:
  Model-independent search for the Abelian $Z'$ gauge boson virtual state based
on the new observable in the processes $e^+ e^- \to l^+ l^-$ is analyzed for
the LEP data. The observable is introduced by using following from
renormalizability of an underlying theory the correlations between the
parameters of the low energy effective Lagrangian and kinematics of the
scattering processes. The central values of the observable are in accordance
with the $Z'$ existence, although no real signal is found at the $1\sigma$
level. Lower limits at the 95% confidence level on the corresponding contact
interaction scale are derived in the range of 15.6 - 18.6 TeV. Comparisons with
other fits are done.


title: On the Erraticity in Random-Cascading alpha Model

abstract:
  The erraticity in the random-cascading $\alpha$ model is revisited. It is
found that in contrary to the previous expectation, even in the pure
single-$\alpha$ random-cascading model without putting in any particle there
exists erraticity behavior and the corresponding entropy indices do not vanish.
This means that the dynamical fluctuations in a pure single-$\alpha$ model
already fluctuate event-by-event. Models with multiple-$\alpha$ strengthen this
fluctuation. Taking double-$\alpha$ model as example, the variation of the
event-space fluctuation strength with the mixing ratio of the two $\alpha$'s is
studied in some detail. The influence of particle number on the results when
particles are putted into the system is also investigated.


title:
Two-Loop Polarization Contributions to Radiative-Recoil Corrections to
  Hyperfine Splitting in Muonium

abstract:
  We calculate radiative-recoil corrections of order
$\alpha^2(Z\alpha)(m/M)E_F$ to hyperfine splitting in muonium generated by the
diagrams with electron and muon polarization loops. These corrections are
enhanced by the large logarithm of the electron-muon mass ratio. The leading
logarithm cubed and logarithm squared contributions were obtained a long time
ago. The single-logarithmic and nonlogarithmic contributions calculated here
improve the theory of hyperfine splitting, and affect the value of the
electron-muon mass ratio extracted from the experimental data on the muonium
hyperfine splitting.


title:
Affleck-Dine leptogenesis via right-handed sneutrino fields in a
  supersymmetric hybrid inflation model

abstract:
  The onset of inflation in hybrid models require fine tuning in the initial
conditions. The inflaton field should have an initial value close to the Planck
scale $M_{P}$, whereas the auxiliary "orthogonal" field must be close to zero
with an extreme accuracy. This problem can be alleviated if the orthogonal
field fastly decays into some states not coupled to the inflaton. Natural
candidates for such states can be the right-handed neutrinos. We show that a
non-trivial evolution of the classic sneutrino fields after inflation offers an
interesting mechanism for generating a correct amount of lepton asymmetry,
which being reprocessed by sphalerons can explain the observed baryon asymmetry
of the Universe. Our scenario implies interesting bounds for the neutrino
masses in the context of seesaw mechanism.


title: Spontaneous CP Violation: Alternative to the Standard Model

abstract:
  We propose a model of soft CP violation that evades the strong CP problem and
can describe observed CP violation in the neutral kaon sector, both direct and
indirect. Our model requires two ``duark'' mesons carrying quark number two
that have complex (CP-violating) bare masses and are coupled to quark pairs.
Aside from the existence of these potentially observable new particles with
masses of several hundred GeV, we predict a flat unitarity triangle ({\it
i.e.,} no observable direct CP violation in the $B$-meson sector) and a
possibly anomalous branching ratio for the decay mode $K^+\to \pi^++\bar{\nu}
\nu$.


title:
Comparison of the FLUKA calculations with CAPRICE94 data on muons in
  atmosphere

abstract:
  In order to benchmark the 3-dimensional calculation of the atmospheric
neutrino flux based on the FLUKA Monte Carlo code, muon fluxes in the
atmosphere have been computed and compared with data taken by the CAPRICE94
experiment at ground level and at different altitudes in the atmosphere. For
this purpose only two additions have been introduced with respect to the
neutrino flux calculation: the specific solar modulation corresponding to the
period of data taking and the bending of charged particles in the atmosphere.
Results are in good agreement with experimental data, although improvements in
the model are possible. At this level, however, it is not possible to
disentangle the interplay between the primary flux and the interaction model.


title: Color Superconductivity: Symmetries and Effective Lagrangians

abstract:
  I briefly review the symmetries and the associated low energy effective
Lagrangian for two light flavor Color Superconductivity (2SC).


title:
Mechanisms of the $f_0(980)$ production in the reaction $\pi^-p\to\pi^0
  \pi^0n$

abstract:
  The model of the pure one-pion exchange mechanism, which gives a good
description of the GAMS results on the alteration of the $S$-wave $\pi^0\pi^0$
mass spectrum in the $f_0(980)$ region in the reaction $\pi^-p\to\pi^0\pi^0n$
with increasing $-t$, is compared with the recent detailed data on the $m$ and
$t$ distributions of the $\pi^-p\to\pi^0\pi^0n$ events obtained by the BNL-E852
Collaboration. It is shown that the predictions of this model are not confirmed
by the BNL data. Therefore the observed phenomenon should be explained by the
different exchange mechanism. It is most likely to be the $a_1$ exchange
mechanism.


title: Boost-invariant particle production in transport equations

abstract:
  The boost-invariant tunneling of particles along the hyperbolas of constant
invariant time, tau^2 = t^2-z^2, is included in the transport equations
describing formation of the quark-gluon plasma in strong color fields. The
non-trivial solutions of the transport equations exist if the boost-invariant
distance between the tunneling particles, measured in the quasirapidity space
eta=1/2 ln ((t+z)/(t-z)), is confined to a finite interval Delta eta. For
realistic values of Delta eta the solutions of the transport equations show
similar characteristics to those found in the standard approach, where the
tunneling takes place at constant time t. In the limit Delta eta -> infinity,
the initial color fields decay instantaneously.


title:
The reaction ${\pi}N{\to}{\omega}N$ revisited: the $\omega{-}N$
  scattering length

abstract:
  We reinvestigate the experimental data on $\omega$--meson production in
pion-nucleon collisions based on both an analytical approach and a Monte Carlo
simulation. Our analysis allows us to study the kinematical peculiarities of
the $\pi^-p{\to}\omega{n}$ reaction at energies close to threshold. Based on
the hypothesis, that the formalism derived in ref. [1] was applied improperly,
the unusually strong energy dependence claimed for the near--threshold cross
section is identified as a purely kinematical effect. Based on this hypothesis,
we deduce an effective ${\pi^-}p{\to}{\omega}n$ cross section that is larger by
an order of magnitude compared to the one commonly used. In addition we extract
a lower limit for the imaginary part $\Im a_{{\omega}N}$ of the ${\omega}N$
scattering length. We find a value of $\Im a_{{\omega}N}{=}0.24{\pm}0.05$ fm,
which is significantly larger than that presently found in the literature.


title:
Eikonal propagators for the high-energy parton-parton scattering in
  gauge theories

abstract:
  By a direct resummation of perturbation theory in the limit of very high
energy and small transferred momentum (the so-called ``eikonal'' limit), we
derive expressions for the truncated-connected quark, antiquark and gluon
propagators in an external gluon field, both for scalar and fermion gauge
theories. These are the basic ingredients to derive ``soft'' high-energy
parton-parton scattering amplitudes, using the LSZ reduction formulae and a
functional integral approach.


title:
Neutrino deep-inelastic scattering: new experimental and theoretical
  results

abstract:
  A review of recent experimental and theoretical studies of characteristics of
neutrino deep-inelastic scattering is presented. Special attentition is paid to
the determination of $\alpha_s$ and $1/Q^2$ non-perturbative effects from QCD
fits to $xF_3$ data at different orders of perturbation theory, with the help
of several theoretical methods.


title: Renormalization of HQET at Three Loops

abstract:
  Three-loop propagator diagrams in HQET can be reduced, using integration by
parts, to 8 basis integrals: 5 trivial ones, two expressible via 3F2, and one
only known up to \epsilon^0. Calculation of the heavy-quark propagator in HQET
is considerably simplified by the non-abelian exponentiation theorem.


title: A description of the neutralino observables in terms of projectors

abstract:
  Applying Jarlskog's treatment of the CKM matrix, to the neutralino mass
matrix in MSSM for real soft gaugino SUSY breaking and $\mu$-parameters, we
construct explicit analytical expressions for the four projectors which acting
on any neutralino state project out the mass eigenstates. Analytical
expressions for the neutralino mass eigenvalues in terms of the various SUSY
parameters, are also given. It is shown that these projectors and mass
eigenvalues are sufficient to describe any physical observable involving
neutralinos, to any order of perturbation theory. As an example, the $e^-e^+
\to \tilde \chi^0_i \tilde \chi^0_j $ cross section at tree level is given in
terms of these projectors. The expected magnitude of their various matrix
elements in plausible SUSY scenarios is also discussed.


title: Branes on the Horizon

abstract:
  Models with extra dimensions are often invoked to resolve cosmological
problems. We investigate the possibility of apparent acausality as seen by a
brane-based observer resulting from signal propagation through the extra
dimensions. Null geodesics are first computed in static and cosmological
single-brane models, following which we derive the equations of motion for the
inter-brane distance in a two-brane scenario, which we use to examine possible
acausality in this more complex setup. Despite observing significant effective
acausality in some situations there is no a priori solution to the horizon
problem using this mechanism. In the two-brane scenario there can be
significant late time violation of gravitational Lorentz invariance, resulting
in the gravitational horizon being larger than the particle horizon, leading to
potential signals in gravitational wave detectors.


title:
Chiral quark models with non-local separable interactions at finite
  temperature and chemical potential

abstract:
  Chiral quark models with non-local covariant separable interactions at finite
temperature and chemical potential are investigated. We develop a formalism in
which the different quark properties are evaluated taking into account the
analytic structure of the quark propagator. In this framework we study the
chiral restoration phase transition for several definite non-local regulators,
including that arising within the instanton liquid picture. We find that in all
cases the chiral transition is of first order for low values of T, turning into
a smooth crossover at a certain "end point". Using model parameters which lead
to the physical pion mass and decay constant, we find for the position of this
"end point" the values (T_E, mu_E) approx. (60-70, 180-210) MeV. We also
discuss the special relevance of the first poles of the quark propagator.


title: Factorization in hard diffraction

abstract:
  In this talk, I reviewed the role of factorization in diffraction hard
scattering.


title: Neutrino production in matter with time-dependent density or velocity

abstract:
  We show that neutrinos can be produced through standard electroweak
interactions in matter with time-dependent density.


title: Measuring the Photon Helicity in Radiative B Decays

abstract:
  We propose a way of measuring the photon polarization in radiative B decays
into K resonance states decaying to K\pi\pi, which can test the Standard Model
and probe new physics. The photon polarization is shown to be measured by the
up-down asymmetry of the photon direction relative to the K\pi\pi decay plane
in the K resonance rest frame. The integrated asymmetry in K_1(1400)\to
K\pi\pi, calculated to be 0.34\pm 0.05 in the Standard Model, is measurable at
currently operating B factories.


title: DREDed Anomaly Mediation

abstract:
  We offer a guide to dimensional reduction (DRED) in theories with anomaly
mediated supersymmetry breaking. Evanescent operators proportional to epsilon
arise in the bare Lagrangian when it is reduced from d=4 to d= (4-2 epsilon)
dimensions. In the course of a detailed diagrammatic calculation, we show that
inclusion of these operators is crucial. The evanescent operators conspire to
drive the supersymmetry-breaking parameters along anomaly-mediation
trajectories across heavy particle thresholds, guaranteeing the ultraviolet
insensitivity.


title: Diffractive Gluon Production in Proton-Nucleus Collisions and in DIS

abstract:
  We derive expressions for the gluon production cross sections in the single
diffractive proton-nucleus scattering and DIS processes in a quasi-classical
approximation. The resulting cross sections include the effects of all multiple
rescatterings in the classical background field of the target proton or
nucleus, which remains intact after the scattering. We also write down an
expression for the inclusive gluon production cross section in DIS in the
quasi-classical approximation.


title:
Determining the Factorization Parameter and Strong Phase Differences in
  B-->D^(*)\pi Decays

abstract:
  The first observation of the color-suppressed decay mode \bar{B}^0_d -->
D^(*)0 \pi^0 by the Belle and CLEO Collaborations makes a quantitative analysis
of the isospin relations for the amplitudes of B --> D^(*)\pi possible. The
strong (isospin) phase difference in B --> D\pi transitions is found to be
about 29^\circ by use the Belle data or 26^\circ by use of the CLEO data,
implying that final-state interactions might not be negligible. Applying the
factorization approximation to I=3/2 and I=1/2 isospin amplitudes of B --> D\pi
decays, we obtain the ratio of the effective Wilson coefficients a^{eff}_1 and
a^{eff}_2: a^{eff}_2/a^{eff}_1 \approx 0.27. A similar analysis shows that the
magnitude of final-state interactions in B --> D^*\pi might be comparable with
that in B --> D\pi, and the factorization hypothesis works consistently in both
of them.


title: Familon emission by dense magnetized plasma

abstract:
  Emission of a familon caused by the processes $e^- \to e^- + \phi$, $ e^- \to
\mu^- + \phi$ in dense magnetized plasma is investigated in the model in which
a familon have both direct and no direct coupling to leptons via plasmon. The
process probabilities and the integral familon action on plasma are calculated.
It is shown that the $ P$ odd interference phenomenon in the process $e^- \to
\mu^- + \phi$ leads to the familon force acting on plasma along the magnetic
field.


title: Effective Neutrino Photon Interaction in a Magnetized Medium

abstract:
  Neutrino-photon processes, forbidden in vacuum, can take place in presence of
a thermal medium or an external electro-magnetic field, mediated by the
corresponding charged leptons (real or virtual). The effect of a medium or an
electromagnetic field is two-fold - to induce an effective $\nu-\gamma$ vertex
and to modify the dispersion relations of all the particles involved to render
the processes kinematically viable. It has already been noted that in presence
of a thermal medium such an electromagnetic interaction translates into the
neutrino acquiring a small effective charge. In this work, we extend this
concept to the case of a thermal medium in presence of an external magnetic
field and calculate the effective charge of a neutrino in the limit of a weak
magnetic field. We find that the effective charge is direction dependent which
is a direct effect of magnetic field breaking the isotropy of the space.


title: $J/\Psi$ suppression in an expanding hadron gas

abstract:
  A model for $J/\Psi$ suppression at a high energy heavy ion collision is
presented. The main (and the only) reason for the suppression is $J/\Psi$
inelastic scattering within hadron matter. The hadron matter is in the form of
a multi-component non-interacting gas. Also the evolution of the gas, both
longitudinal and transverse, is taken into account. It is shown that under such
circumstances and with $J/\Psi$ disintegration in nuclear matter added,
$J/\Psi$ suppression evaluated agrees well with NA38 and NA50 data.


title: Neutrino Interactions In Oscillation Experiments

abstract:
  We calculate neutrino induced cross-sections relevant for oscillation
experiments, including the $\tau$-lepton threshold for quasi-elastic, resonance
and deep inelastic scattering. In addition to threshold effects, we include
nuclear corrections for heavy targets which are moderate for quasi-elastic and
large for single pion production. Nuclear effects for deep inelastic reactions
are small. We present cross sections together with their nuclear corrections
for various channels which are useful for interpreting the experimental results
and for determining parameters of the neutrino sector..


title:
Is a Large Intrinsic k_T Needed to Describe Photon + Jet Photoproduction
  at HERA?

abstract:
  We study the photoproduction of an isolated photon and a jet based on a code
of partonic event generator type which includes the full set of next-to-leading
order corrections. We compare our results to a recent ZEUS analysis in which an
effective k_T of the incoming partons has been determined. We find that no
additional intrinsic k_T is needed to describe the data.


title: On Big Bang Relics, the Neutrino Mass and the Spectrum of Cosmic Rays

abstract:
  It is shown that high-energy features of the cosmic ray spectrum, in
particular the kink around 4 PeV and the corresponding change in spectral
index, may be explained from interactions between highly energetic cosmic
protons and relic Big Bang antineutrinos, if the latter have a rest mass of
about 0.4 eV/$c^2$. This explanation is supported by experimental data from
extensive air-shower experiments, and in particular by the observation (Fly's
Eye) of a second kink around 300 PeV, and by the abrupt change in the chemical
composition of the cosmic ray spectrum that occurs at that energy. Both facts
follow naturally from our theory, which predicts additional verifiable features
of the cosmic ray spectrum in the few-PeV region, e.g. an abrupt decrease in
the $p/\alpha$ ratio.


title: Connecting bimaximal neutrino mixing to a light sterile neutrino

abstract:
  It is shown that if small neutrino masses owe their origin to the
conventional seesaw mechanism and the MNS mixing matrix is in the exact
bimaximal form, then there exist symmetries in the theory that allow one of the
righthanded neutrinos to become naturally massless, making it a candidate for
the sterile neutrino discussed in the literature. Departures from the exact
bimaximal limit leads to tiny mass for the sterile neutrino as well as its
mixing to the active neutrinos. This provides a minimal theoretical framework
where a simultaneous explanation of the solar, atmospheric and LSND
observations within the so-called 3+1 scenario may be possible.


title: Novel phases and transitions in Color Flavor Locked matter

abstract:
  We analyze the phases of dense quark matter at nonzero quark masses. We map
out the phase diagrams for charged quark matter as well as charge neutral
matter containing leptons. We find that in Color Flavor Locked (CFL) quark
matter, the symmetric phase with equal numbers of $u$, $d$ and $s$ quarks is
unlikely to occur in nature. Various less symmetric phases with additional
meson condensates may play a role in neutron star cores, however, in agreement
with the analysis of Bedaque and Sch\"afer. We discuss the implications of
these novel color superconducting quark matter phases and their transitions for
neutron stars.


title: 4D Models of Scherk-Schwarz GUT Breaking via Deconstruction

abstract:
  We examine new classes of GUT models where the GUT gauge group is broken by a
4D analogue of the Scherk-Schwarz mechanism. These models are inspired by
``deconstructed'' 5D Scherk-Schwarz orbifold models. However, no fine tuning of
parameters or assumption of higher dimensional Lorentz invariance is necessary,
and the number of lattice sites can be as low as just two. These models provide
simple ways to solve the doublet-triplet splitting problem, changes proton
decay predictions, and may provide insight into the structure of the CKM
matrix. Since the number of fields in these models is finite, the corrections
to the unification of gauge couplings can be reliably calculated, and as
expected result only in threshold corrections to the differential running of
the couplings. Our analysis also suggests new 4D models which can enjoy the
benefits of orbifold models but cannot be obtained by deconstruction of a 5D
model.


title:
Flavor Symmetry on Non-Commutative Compact Space and $SU(6) \times
  SU(2)_R$ Model

abstract:
  In the four-dimensional effective theory from string compactification
discrete flavor symmetries arise from symmetric structure of the compactified
space and generally contain both the $R$ symmetry and non-$R$ symmetry. We
point out that a new type of non-Abelian flavor symmetry can also appear if the
compact space is non- commutative. Introducing the dihedral group $D_4$ as such
a new type of flavor symmetry together with the $R$ symmetry and non-$R$
symmetry in $SU(6) \times SU(2)_R$ model, we explain not only fermion mass
hierarchies but also hierarchical energy scales including the breaking scale of
the GUT-type gauge symmetry, intermediate Majorana masses of R-handed neutrinos
and the scale of $\mu$-term.


title: GUT Breaking on the Lattice

abstract:
  We construct a supersymmetric grand unified model in the framework of a
latticized extra dimension. The SU(5) symmetries on the lattice are broken by
the vacuum expectation values of the link fields connecting adjacent SU(5)
sites, leaving just the MSSM at low energies. Below the SU(5) breaking scale,
the theory gives rise to a similar spectrum as in orbifold breaking of SU(5)
symmetry in 5 dimensions, and shares many features with the latter scenario. We
discuss gauge coupling unification and proton decay emphasizing the differences
with respect to the usual grand unified theories. Our model may be viewed as an
effective four dimensional description of the orbifold symmetry breaking in
higher dimensions.


title: Recent results in the BFKL theory

abstract:
  The Balitsky-Fadin-Kuraev-Lipatov (BFKL) approach for the cross sections at
high energy $\sqrt s$ in perturbative QCD is briefly reviewed. The role of
gluon Reggeization in the derivation of the BFKL equation and its compatibility
with $s$-channel unitarity (``bootstrap'') are discussed.


title: The rare top decay $t\to c g$ in topcolor assisted technicolor models

abstract:
  In the framework of topcolor-assisted technicolor(TC2) models, we calculate
the contributions of flavor changing scalar couplings involved the neutral
top-pion $\pi_{t}^{0}$ and top-Higgs $h_{t}^{0}$ to the branching ratio
$B_{r}(t\longrightarrow cg)$. We find that the value of $B_{r}(t\longrightarrow
cg)$ can reach $ 1\times10^{-3}$ with reasonable values of the parameters in
TC2 models, which may be testable in the future experiments.