title: Charged Higgs production from SUSY particle cascade decays at the LHC

abstract:
  We analyze the cascade decays of the scalar quarks and gluinos of the Minimal
Supersymmetric extension of the Standard Model, which are abundantly produced
at the Large Hadron Collider, into heavier charginos and neutralinos which then
decay into the lighter ones and charged Higgs particles, and show that they can
have substantial branching fractions. The production rates of these Higgs
bosons can be much larger than those from the direct production mechanisms, in
particular for intermediate values of the parameter $\tan \beta$, and could
therefore allow for the detection of these particles. We also discuss charged
Higgs boson production from direct two-body top and bottom squark decays as
well as from two- and three-body gluino decays.


title: Scalar perturbations during multiple-field slow-roll inflation

abstract:
  We calculate the scalar gravitational and matter perturbations in the context
of slow-roll inflation with multiple scalar fields, that take values on a
(curved) manifold, to first order in slow roll. For that purpose a basis for
these perturbations determined by the background dynamics is introduced and
multiple-field slow-roll functions are defined. To obtain analytic solutions to
first order, the scalar perturbation modes have to be treated in three
different regimes. Matching is performed by analytically identifying leading
order asymptotic expansions in different regions. Possible sources for
multiple-field effects in the gravitational potential are the particular
solution caused by the coupling to the field perturbation perpendicular to the
field velocity, and the rotation of the basis. The former can contribute even
to leading order if the corresponding multiple-field slow-roll function is
sizable during the last 60 e-folds. Making some simplifying assumptions, the
evolution of adiabatic and isocurvature perturbations after inflation is
discussed. The analytical results are illustrated and checked numerically with
the example of a quadratic potential.


title: Higgs Physics at a Future e+e- Linear Collider

abstract:
  This letter reviews the potential of a high luminosity e+e- linear collider
(LC) in the precision study of the Higgs boson profile. The complementarity
with the Large Hadron Collider (LHC) Higgs physics program is briefly
discussed.


title:
Physical Reach of a Neutrino Factory in the 2+2 and 3+1 Four-Family
  Scenario

abstract:
  We compare the physical reach of a Neutrino Factory in the 2+2 and 3+1
four-family models, with similar results in the two schemes; in both cases huge
CP-violating effects can be observed with a near detector in the $\nu_\mu \to
\nu_\tau$ channel. We also study the capability of long baseline experiments
(optimized for the study of the three-family mixing parameter space) in
distinguishing a three (active) neutrino model from a four-family scenario.


title:
On hard electroproduction of mesons: helicity flip amplitudes with
  tensor gluon contributions

abstract:
  We consider hard electroproduction of mesons at twist-3 level and focus our
attention on helicity flip amplitudes corresponding to the production of
transversely polarized mesons by transverse photons. We demonstrate that
helicity-flip amplitude for the transversely polarized particles are closely
related to the contributions of the matrix elements of the tensor gluon
operator which can serve as pure gluonic probe of the hadrons. Using standard
factorisation approach and Wanzura-Wilczek approximation for the twist-3 matrix
elements we find that such amplitudes do not have divergencies from the
endpoint regions which appear in the other twist-3 amplitudes.


title: CP Violation in SUSY

abstract:
  Supersymmetry exhibts new sources of CP violation. We discuss the
implications of these new contributions to CP violation both in the K and B
physics. We show that CP violation puts severe constraints on low energy SUSY,
but it represents also a promising ground to look for signals of new physics.


title: Reactor-based Neutrino Oscillation Experiments

abstract:
  The status of neutrino oscillation searches employing nuclear reactors as
sources is reviewed. This technique, a direct continuation of the experiments
that proved the existence of neutrinos, is today an essential tool in
investigating the indications of oscillations found in studying neutrinos
produced in the sun and in the earth's atmosphere. The low-energy of the
reactor \nuebar makes them an ideal tool to explore oscillations with small
mass differences and relatively large mixing angles.
  In the last several years the determination of the reactor anti-neutrino flux
and spectrum has reached a high degree of accuracy. Hence measurements of these
quantities at a given distance L can be readily compared with the expectation
at L = 0, thus testing \nuebar disappearance.
  While two experiments, Chooz and Palo Verde, with baselines of about 1 km and
thus sensitive to the neutrino mass differences associated with the atmospheric
neutrino anomaly, have collected data and published results recently, an
ambitious project with a baseline of more than 100 km, Kamland, is preparing to
take data. This ultimate reactor experiment will have a sensitivity sufficient
to explore part of the oscillation phase space relevant to solar neutrino
scenarios. It is the only envisioned experiment with a terrestrial source of
neutrinos capable of addressing the solar neutrino puzzle.


title:
Preliminary Calculation of $\alpha_s$ from Green Functions with
  Dynamical Quarks

abstract:
  We present preliminary results on the computation of the QCD running coupling
constant in the $\widetilde{MOM}$ scheme and Landau gauge with two flavours of
dynamical Wilson quarks. Gluon momenta range up to about 7 GeV ($\beta =$ 5.6,
5.8 and 6.0) with a constant dynamical-quark mass. This range already allows to
exhibit some evidence for a sizable $1/\mu^2$ correction to the asymptotic
behaviour, as in the quenched approximation, although a fit without power
corrections is still possible with a reasonable $\chi^2$. Following the
conclusions of our quenched study, we take into account $1/\mu^2$ correction to
the asymptotic behaviour. We find $\Lambda_{\rm \bar{MS}}^{N_f=2} = 264(27)
{\rm MeV} \times [{a^{-1}(5.6,0.1560)}/{2.19 {\rm GeV}}] $, which leads to
$\alpha_s(M_Z) = 0.113(3)(4)$. The latter result has to be taken as a
preliminary indication rather than a real prediction in view of the systematic
errors still to be controlled. Still, being two sigmas below the experimental
result makes it very encouraging.


title: Anomalous magnetic moment of muon and L-violating Supersymmetric Models

abstract:
  We consider L-violating Supersymmetric Models to explain the recent muon
$g_{\mu} -2$ deviation from the Standard Model. The order of trilinear
L-violating couplings which we require also generate neutrino mass which is
somewhat higher than expected unless one considers highly suppressed $L-R$
mixing of sfermions. However, without such fine tuning for sfermions it is
possible to get appropriate muon $g_{\mu}-2$ deviation as well as neutrino mass
if one considers some horizontal symmetry for the lepton doublet. Our studies
show that $g_{\mu} -2$ deviation may not imply upper bound of about 500 GeV on
masses of supersymmetric particles like chargino or neutralino as proposed by
other authors for R parity conserving supersymmetric models. However, in our
scenario sneutrino mass is expected to be light ($\sim 100$ GeV) and
$e-\mu-\tau$ universality violation may be observed experimentally in near
future.


title: Tachyonic Preheating

abstract:
  I review the theory of preheating after inflation, focusing on the recently
found tachyonic preheating in the theories with spontaneous symmetry breaking.
This occurs due to the tachyonic instability of the scalar field near the top
of its effective potential. Contrary to the common expectation, tachyonic
instability converts most of the energy into that of colliding classical waves
very rapidly, within a single oscillation. Efficient tachyonic preheating is
typical for the hybrid inflationary scenario, including SUSY motivated and
brane inflation models.


title: Leptogenesis via Collisions: Leaking Lepton Number to the Hidden Sector

abstract:
  We propose a lepto-baryogenesis mechanism in which the non-zero B-L of the
universe is produced in out-of-equilibrium, lepton number and CP violating
scattering processes that convert ordinary particles into particles of some
hidden sector. In particular, we consider the processes $l \phi > l' \phi',
\bar l' \bar phi'$ mediated by the heavy Majorana neutrinos $N$ of the seesaw
mechanism, where $l$ and $\phi$ are ordinary lepton and Higgs doublets and
$l'$, $\phi'$ their hidden counterparts. Such a leptogenesis mechanism is
effective even if the reheating temperature is much smaller than the heavy
neutrino masses. In particular, it can be as low as $10^{9}$ GeV.


title: Analytic Perturbation Theory in analyzing some QCD observables

abstract:
  The paper is devoted to application of recently devised ghost-free Analytic
Perturbation Theory (APT) for analysis of some QCD observables. We start with
the discussion of the main problem of the perturbative QCD -- ghost
singularities and with the resume of this trouble solution within the APT.
  By a few examples in the various energy and momentum transfer regions (with
the flavor number f=3, 4 and 5) we demonstrate the effect of improved
convergence of the APT modified perturbative QCD expansion. Our first
observation is that in the APT analysis the three-loop contribution $\sim
\alpha_s^3$) is as a rule numerically inessential. This gives raise a hope for
practical solution of the well-known problem of asymptotic nature of common QFT
perturbation series.
  The second result is that a usual perturbative analysis of time-like events
with the big $\pi^2$ term in the $\alpha_s^3$ coefficient is not adequate at
$s\leq 2 \GeV^2$. In particular, this relates to $\tau$ decay.
  Then, for the "high" (f=5) region it is shown that the common two-loop (NLO,
NLLA) perturbation approximation widely used there (at $10
\GeV\lesssim\sqrt{s}\lesssim 170 \GeV$) for analysis of shape/events data
contains a systematic negative error of a 1--2 per cent level for the extracted
$\bar{alpha}_s^{(2)} $ values.
  Our physical conclusion is that the $\bar{alpha}_s(M^2_Z)$ value averaged
over the f=5 data appreciably differs $<bar{alpha}_s(M^2_Z)>_{f=5}\simeq 0.124$
from the currently accepted "world average" (=0.118).}


title: Unitary mixing scalar-vector in $\xi$ gauge

abstract:
  We study the effect of unitary mixing of scalar and vector fields in general
$\xi$ gauge. This effect takes place for non-conserved vector currents and
$\xi$ gauge generates some additional problems with unphysical scalar field. We
obtained solutions of Dyson-Schwinger equations and perfomed the
renormalization of full propagators. The key feature of renormalization is the
usage of Ward identity, which relates some different Green functions. We found
that using Ward identity leads to disappearing of $\xi$-dependence in
renormalized matrix element.


title:
Theoretical interpretation of the experiments on Parametric X-ray
  radiation in case of backward diffraction

abstract:
  The spectral-angular and angular distributions of parametric X-radiation for
case of backward diffraction (particular case of Bragg geometry scheme) is
discussed. It is shown that in case of Bragg geometry it is necessary to use
dynamical approach for PXR consideration. The comparison of the theory and
experiment is carried out.


title: A quark loop model for heavy mesons

abstract:
  I consider a model based on a quark--meson interaction Lagrangian. The
transition amplitudes are evaluated by computing diagrams in which heavy and
light mesons are attached to quark loops. The light chiral symmetry relations
and the heavy quark spin-flavour symmetry dictated by the heavy quark effective
theory are implemented. The model allows to compute the decay form factors and
therefore can give predictions for the decay rates, the invariant mass spectra
and the asymmetries.


title: R-parity violation and the cosmological gravitino problem

abstract:
  Based on the R-parity violation option of the minimal supersymmetric Standard
Model, we examine the scenario where the massive gravitino, relic from the hot
big-bang, is the lightest supersymmetric particle and can decay through one or
several of the trilinear R-parity violating interactions. We calculate the
rates of the gravitino decay via the various three-body decay channels with
final states involving three quarks and/or leptons. By taking into account the
present constraints on the trilinear R-parity violating coupling constants and
assuming the gravitino and scalar superpartner masses do not exceed ${\cal
O}(10TeV)$, it turns out that the gravitinos could easily have decayed before
the present epoch but not earlier than the big-bang nucleosynthesis one.
Therefore, the considered scenario would upset the standard big-bang
nucleosynthesis and we conclude that it does not seem to constitute a natural
solution for the cosmological gravitino problem.


title: Extragalactic Sources for Ultra High Energy Cosmic Ray Nuclei

abstract:
  In this article we examine the hypothesis that the highest energy cosmic rays
are complex nuclei from extragalactic sources. Under reasonable physical
assumptions, we show that the nearby metally rich starburst galaxies (M82 and
NGC 253) can produce all the events observed above the ankle. This requires
diffusion of particles below $10^{20}$ eV in extragalactic magnetic fields $B
\approx 15$ nG. Above $10^{19}$ eV, the model predicts the presence of
significant fluxes of medium mass and heavy nuclei with small rate of change of
composition. Notwithstanding, the most salient feature of the
starburst-hypothesis is a slight anisotropy induced by iron debris just before
the spectrum-cutoff.


title: Phi Mesons from a Hadronic Fireball

abstract:
  Production of $\phi$ mesons is considered in the course of heavy-ion
collisions at SPS energies. We investigate the possible difference in momentum
distributions of $\phi$ mesons measured via their leptonic ($\mu^+\mu^-$) and
hadronic ($K^+K^-$) decays. Rescattering of secondary kaons in the dense hadron
gas together with the influence of in-medium kaon potential can lead to a
relative decrease of a $\phi$ yield observed in the hadronic channel. We
analyze how the in-medium modifications of meson properties affect apparent -
reconstructed momentum distributions of $\phi$ mesons. Quantitative results are
presented for central Pb+Pb collisions at $E_{beam}=158 GeV/A$.


title: One-loop stau masses in the effective potential approach

abstract:
  We calculate the one-loop contributions to the tau slepton masses in the
Minimal Supersymmetric Standard Model in the effective potential approach. For
the majority of parameter space under study, those corrections are shown to
elevate the value of the lightest stau mass.


title:
Supersymmetry and electroweak breaking with large and small extra
  dimensions

abstract:
  We consider the problem of supersymmetry and electroweak breaking in a 5d
theory compactified on an $S^{1}/Z_{2}$ orbifold, where the extra dimension may
be large or small. We consider the case of a supersymmetry breaking 4d brane
located at one of the orbifold fixed points with the Standard Model gauge
sector, third family and Higgs fields in the 5d bulk, and the first two
families on a parallel 4d matter brane located at the other fixed point. We
compute the Kaluza-Klein mass spectrum in this theory using a matrix technique
which allows us to interpolate between large and small extra dimensions. We
also consider the problem of electroweak symmetry breaking in this theory and
localize the Yukawa couplings on the 4d matter brane spatially separated from
the brane where supersymmetry is broken. We calculate the 1-loop effective
potential using a zeta-function regularization technique, and find that the
dominant top and stop contributions are separately finite. Using this result we
find consistent electroweak symmetry breaking for a compactification scale {$
1/R \approx 830$ GeV} and a lightest Higgs boson mass $m_{h} \approx 170$ GeV.


title: Bounding Noncommutative QCD

abstract:
  Jurco, Moller, Schraml, Schupp, and Wess have shown how to construct
noncommutative SU(N) gauge theories from a consistency relation. Within this
framework, we present the Feynman rules for noncommutative QCD and compute
explicitly the most dangerous Lorentz-violating operator generated through
radiative corrections. We find that interesting effects appear at the one-loop
level, in contrast to conventional noncommutative U(N) gauge theories, leading
to a stringent bound. Our results are consistent with others appearing recently
in the literature that suggest collider limits are not competitive with
low-energy tests of Lorentz violation for bounding the scale of spacetime
noncommutativity.


title:
B-quark mediated neutrinoless $\mu^--e^-$ conversion in presence of
  R-parity violation

abstract:
  We found that in supersymmetric models with R-parity non-conservation the
b-quarks may appreciably contribute to exotic neutrinoless muon-electron
conversion in nuclei via the triangle diagram with two external gluons. This
allowed us to extract previously overlooked constraints on the third generation
trilinear R-parity violating parameters significantly more stringent than those
existing in the literature.


title:
Probing Top-Charm Associated Production at the LHC in the R-parity
  violating MSSM

abstract:
  We present the analytical and numerical investigations of top-charm
associated production at the LHC in the framework of the R-parity violating
MSSM. The numerical analysis of their production rates is carried out in the
mSUGRA scenario with some typical parameter sets. The results show that the
cross sections of associated $t\bar{c}(\bar{t}c)$ production via gluon-gluon
fusion can reach 5% of that via $d\bar{d}$ annihilation. The total cross
section will reach the order of $10 \sim 10^2 ~fb$ and the cross sections are
strongly related to the R-parity violating parameters.


title:
Nonleading charmed quark mass corrections to K^0-anti K^0 mixing in the
  standard model

abstract:
  The nonleading corrections in the inverse mass of the heavy charmed quark to
the effective local \Delta S=2 Lagrangian of K^0-anti K^0 mixing are calculated
within the standard model.


title: BLM scale for the pion transition form factor

abstract:
  The NLO Brodsky-Lepage-Mackenzie (BLM) scale for the pion transition form
factor has been determined. To achieve that, a consistent calculation up to
nf-proportional NNLO contributions to both the hard-scattering amplitude and
the perturbatively calculable part of the pion distribution amplitude has been
performed. By combining and matching the results obtained for these two
amplitudes, a proper cancellation of collinear singularities has been
established and the gamma5 ambiguity problem (related to the use of the
dimensional regularization method) has been resolved by using the naive-gamma5
as well as the 't Hooft-Veltman (HV) schemes. It has been demonstrated that the
prediction for the pion transition form factor is independent of the
factorization scale muF at every order in the strong coupling constant, making
it possible to use the simplest choice muF^2=Q^2 at the intermediate steps of
the calculation. Assuming the pion asymptotic distribution amplitude and
working in the \bar{MS} scheme, we have found the BLM scale to be muR^2=muBLM^2
~ Q^2/9. Based on the same distribution, the complete NLO prediction for the
pion transition form factor has been calculated in the alphaV definition of the
QCD coupling renormalized at muR^2=muV^2 = e^{5/3} muBLM^2 ~ Q^2/2. It is in
good agreement with the presently available experimental data.


title: A chiral theory of strange sea distributions in the nucleon

abstract:
  Theoretical predictions are given for the strange sea distributions in the
nucleon based on the flavor SU(3) chiral quark soliton model, with emphasis
upon the asymmetry of quark and antiquark distributions. We find that the
quark-antiquark asymmetry of the strange sea is much larger for the
longitudinally polarized distribution functions than for the unpolarized ones.
A preliminary comparison with the CCFR data for the unpolarized $s$-quark
distribution and with the LSS fits of the longitudinally polarized distribution
functions is encouraging.


title: Right-handed Neutrinos as Superheavy Dark Matter

abstract:
  We propose that right-handed neutrinos are very long-lived dark matter. The
long lifetime is realized by the separation of the wavefunction of right-handed
neutrinos and that of other fermions in an extra dimension. Such long-lived and
superheavy dark matter can naturally explain observed ultra high energy cosmic
rays above the GZK cutoff (5 * 10^{19} eV) and huge amounts of cold dark matter
simultaneously. Furthermore, the exponentially suppressed Yukawa couplings of
right-handed neutrinos leads to the high predictablilty on the mass parameter
of the neutrinoless double beta decay, as all the models which predict very
small neutrino mass of one generation.


title: See-saw mechanism and four light neutrino state

abstract:
  A formal proof is given that in a see-saw type neutrino mass matrix with only
two neutrino mass scales ($m_D \ll m_R$) and the maximal rank of $m_{R(D)}$, we
can not get a fourth light sterile neutrino.


title: Isospin breaking corrections to low-energy pi-K scattering

abstract:
  We evaluate the matrix elements for the processes pi^0 K^0 -> pi^0 K^0 and
pi^- K^+ -> pi^0 K^0 in the presence of isospin breaking terms at leading and
next-to-leading order. As a direct application the releveant combination of the
S-wave scattering lengths involved in the pion-kaon atom lifetime is
determined. We discuss the sensitivity of the results with respect to the input
parameters.


title: Conformal expansions and renormalons

abstract:
  The large-order behaviour of QCD is dominated by renormalons. On the other
hand renormalons do not occur in conformal theories, such as the one describing
the infrared fixed-point of QCD at small beta_0 (the Banks--Zaks limit). Since
the fixed-point has a perturbative realization, all-order perturbative
relations exist between the conformal coefficients, which are renormalon-free,
and the standard perturbative coefficients, which contain renormalons.
Therefore, an explicit cancellation of renormalons should occur in these
relations. The absence of renormalons in the conformal limit can thus be seen
as a constraint on the structure of the QCD perturbative expansion. We show
that the conformal constraint is non-trivial: a generic model for the
large-order behaviour violates it. We also analyse a specific example, based on
a renormalon-type integral over the two-loop running-coupling, where the
required cancellation does occur.


title:
Initial conditions and charged multiplicities in ultra-relativistic
  heavy-ion collisions

abstract:
  At ultra-relativistic energies the minijet production in heavy-ion collisions
becomes sensitive to semi-hard parton rescatterings in the initial stages of
the process. As a result global characteristics of the event, like the initial
minijet density, become rather insensitive on the infrared cutoff that
separates hard and soft interactions. This allows to define a nearly
parameter-free {\it saturation cutoff} at which the initial conditions may be
computed. As an application we study the centrality dependence of the charged
particle multiplicity, which is compared with present RHIC data and predicted
at higher energies.


title: On the form factor of physical mesons and their distribution function

abstract:
  This work addresses more to the technical rather than to the physical
problem, how to calculate analytically the form factor $F(Q)$, the associated
mean-square radius $<r^2>$, and the distribution function $\Phi(x,Q^2)$ for a
given light-cone wave function $\Psi_{q\bar q}(x,\vec k_{\perp})$ of the pion.
They turn out to be functions of only one dimensionless parameter, which is the
ratio of the constituent quark mass and an effective Bohr momentum which
measures the width of the wave function in momentum space. Both parameters are
subject to change in the future, when the presently used solution for the over
simplified $\uparrow\downarrow$-model will be replaced by something better.
Their relation to and agreement with experiment is discussed in detail.
  The procedure can be generalized also to other hadrons.


title: The Structure of Screening in QED

abstract:
  The possibility of constructing charged particles in gauge theories has long
been the subject of debate. In the context of QED we have shown how to
construct operators which have a particle description. In this paper we further
support this programme by showing how the screening interactions arise between
these charges. Unexpectedly we see that there are two different gauge invariant
contributions with opposite signs. Their difference gives the expected result.


title: SUSY Scaling Violations and UHECR

abstract:
  Advancing QCD toward astroparticle applications generates new challenges for
perturbation theory, such as the presence of large evolution scales with
sizeable scaling violations involving both the initial and the final state of a
collision. Possible applications in the context of Ultra High Energy Cosmic
Rays (UHECR) of these effects are discussed.


title:
Muon anomalous magnetic dipole moment in the $\mu$-problem solvable
  extra U(1) models

abstract:
  The recent measurement of the muon anomalous magnetic dipole moment shows
2.6$\sigma$ deviation of $a_\mu$ from the standard model prediction which can
be explained by a chargino-sneutrino loop correction in the supersymmetric
models. In this paper we consider extra U(1) models where the $\mu$ parameter
is radiatively generated. This model predicts the sign of $\mu$ is positive in
wide parameter regions. But even the 2$\sigma$ constraint causes a serious
contradiction to the experimental bound of the extra neutral gauge boson mass.
Although a minimal supergravity scenario is ruled out, a very small window is
remained as an allowed region for a no-scale model with non-universal gaugino
masses.


title:
Ultra high energy cosmic rays from extragalactic astrophysical sources:
  energy losses and spectra

abstract:
  The energy losses and spectra of Ultra High Energy Cosmic Rays (UHECR) are
calculated for protons as primary particles. The attention is given to the
energy losses due to electron-positron production in collisions with the
microwave 2.73 K photons. The energy spectra are calculated for several models,
which differ by production spectra and by source distribution, namely: (i)
Uniform distribution of the sources with steep generation spectra with indices
2.4 - 2.7, with cosmological evolution and without it. In this case it is
possible to fit the shape of the observed spectrum up to 8.10^{19} eV, but the
required CR emissivity is too high and the GZK cutoff is present. (ii) Uniform
distribution of the sources with flat generation spectrum dE/E^2 which is
relevant to GRBs. The calculated spectrum is in disagreement with the observed
one. The agreement at E\lesssim 8.10^{19} eV can be reached using a complex
generation spectrum, but the required CR emissivity is three orders of
magnitude higher than that of GRBs, and the predicted spectrum has the GZK
cutoff. (iii) The case of local enhancement within region of size 10 - 30 Mpc
with overdensity given by factor 3- 30. The overdensity larger than 10 is
needed to eliminate the GZK cutoff.


title: Multi-Localization in Multi-Brane Worlds

abstract:
  We study bulk fields in various multi-brane models with localized gravity. In
the case of spin 0, 1/2 and 3/2 fields, the non-trivial background geometry
itself can induce (multi-) localization of the zero modes along the extra
dimension. The addition of appropriate mass terms controls the strength or/and
the position of this localization and can induce (multi-) localization of spin
1 fields as well. We show that multi-brane models may also give rise to
anomalously light KK modes which are also localized. The possibility of
multi-localization in the context of supersymmetric brane world models in AdS_5
spacetime is also discussed.


title: Signal of heavy Majorana neutrinos at hadron colliders

abstract:
  The lepton number violating signal of like-sign-dileptons (LSD), p p \to
\ell^\pm\ell^\pm + 2 jets, is investigated within a model of mixing in the
neutrino sector assuming the existence of heavy Majorana neutrino states with a
left--handed coupling to the light leptons. The LSD signal receives
contributions both from the resonant production of a heavy Majorana neutrino
(N) and from the exchange of a virtual N in the WW fusion mechanisms. These two
possibilities are discussed in detail and compared. Helicity amplitudes are
given pointing out differences with calculations previously reported by other
authors. The signal cross--sections are computed at the energy of the LHC
collider (sqrt{S}=14 TeV) at CERN and within the existing experimental limits
on the mixing couplings, including those coming from neutrinoless double beta
decay. Detailed angular distributions of signal reactions which are
complementary to previous studies on the argument are presented.


title: QCD Factorized Drell-Yan Cross Section at Large Transverse Momentum

abstract:
  We derive a new factorization formula in perturbative quantum chromodynamics
for the Drell-Yan massive lepton-pair cross section as a function of the
transverse momentum $Q_T$ of the pair. When $Q_T$ is much larger than the
pair's invariant mass $Q$, this factorization formula systematically resums the
logarithmic contributions of the type $\alpha_s^m \ln^m(Q_T^2/Q^2)$ to all
orders in the strong coupling $\alpha_s$. When $Q_T\sim Q$, our formula yields
the same Drell-Yan cross section as conventional fixed order QCD perturbation
theory. We show that resummation is important when the collision energy
$\sqrt{S}$ is large enough and $Q_T\gg Q$, and we argue that perturbative
expansions are more stable and reliable in terms of the modified factorization
formula.


title: Are there nu_mu or nu_tau in the flux of solar neutrinos on earth?

abstract:
  Using the model independent method of Villante, Fiorentini, Lisi, Fogli,
Palazzo, and the rates measured in the SNO and Super-Kamiokande solar neutrino
experiment, we calculate the amount of active nu_mu or nu_tau present in the
flux of solar neutrinos on Earth. We show that the probability of
nu_e->nu_{mu,tau} transitions is larger than zero at 99.89% CL. We find that
the averaged flux of nu_{mu,tau} on Earth is larger than 0.17 times the 8B nu_e
flux predicted by the BP2000 Standard Solar Model at 99% CL. We discuss also
the consequences of possible nu_e->anti-nu_{mu,tau} or nu_e->anti-nu_e
transitions of solar neutrinos. We derive a model-independent lower limit of
0.52 at 99% CL for the ratio of the 8B nu_e flux produced in the Sun and its
value in the BP2000 Standard Solar Model.


title:
A note on the factorization scale dependence of the PQCD predictions for
  exclusive processes

abstract:
  We briefly review the calculational procedure for the PQCD prediction for
hard exclusive quantities and reconsider the problem of the factorization scale
dependence.


title: Neutrino induced hard exclusive D_s production

abstract:
  Motivated by the possibility to use high intensity neutrino beams for
neutrino-nucleon scattering experiments we analyze charged current induced
exclusive meson production within the framework of generalized parton
distributions. The cross section for hard exclusive D_s production is estimated
in this formalism to leading order in QCD. The integrated cross section proves
to be sizable. It is shown that the considered process is well suited to
provide novel information on the gluon structure of nucleons, which is
contained in the generalized gluon parton distribution.


title:
A natural solution for the \mu problem with anomalous U(1)_A gauge
  symmetry

abstract:
  Recently we proposed an attractive scenario of grand unified theories with
anomalous $U(1)_A$ gauge symmetry, in which doublet-triplet splitting is
naturally realized in SO(10) unification using Dimopoulos-Wilczek mechanism and
realistic quark and lepton mass matrices can be obtained in a simple way. In
this paper we show that there is a mechanism in which the doublet Higgs obtains
the supersymmetric mass which is proportional to the SUSY breaking parameters.
This mechanism can be applied easily in the above scenario. The point is that
the mass term, which is forbidden by SUSY zero mechanism, can be induced by
SUSY breaking. The proportional coefficient is controlled by the anomalous
U(1)_A charges.


title:
Electroweak baryogenesis mediated by locally supersymmetry-breaking
  defects

abstract:
  We consider the scenario of electroweak baryogenesis mediated by cosmological
defect in models of supersymmetry breaking. When the effective electroweak
breaking scale is raised in the defect configuration, the mechanism of
electroweak baryogenesis works at a higher energy scale. The baryon charge
produced by the mechanism is captured in the defect, protected from sphalerons
and then released when the defect decay.


title:
Renormalization of the two-photon vacuum polarization and the self
  energy vacuum polarization for a tightly bound electron

abstract:
  The renormalization method of Bogoljubov-Parasiuk-Hepp-Zimmermann (BPHZ) is
used in order to derive the renormalized energy shift due to the gauge
invariant K\"all\'en-Sabry diagram of the two-photon vacuum polarization (VPVP)
as well as the self energy vacuum polarization S(VP)E beyond the Uehling
approximation. It is outlined, that no outer renormalization is required for
the two-photon vacuum polarization and that only the inner renormalization has
to b e accomplished. It is shown that the so-called nongauge invariant spurious
term is absent for a wide class of vacuum polarization (VP) diagrams if one
applies the widely used spherical expansion of bound and free-electron propagat
or. This simplifies significantly calculations in bound state quantum
electrodynamis . As one result of our paper the use of the BPHZ-approach in
bound state QED is established.


title:
Constraints on the Minimal Supergravity Model and Prospects for SUSY
  Particle Production at Future Linear e^+ e^- Colliders

abstract:
  We perform a complete analysis of the supersymmetric particle spectrum in the
Minimal Supergravity (mSUGRA) model where the soft SUSY breaking scalar masses,
gaugino masses and trilinear couplings are unified at the GUT scale, so that
the electroweak symmetry is broken radiatively. We show that the present
constraints on the Higgs boson and superparticle masses from collider searches
and precision measurements still allow for large regions of the mSUGRA
parameter space where charginos, neutralinos, sleptons and top squarks as well
as the heavier Higgs particles, are light enough to be produced at the next
generation of $\ee$ linear colliders with center of mass energy around
$\sqrt{s} \sim 800$ GeV, with sizeable cross sections. An important part of
this parameter space remains even when we require that the density of the
lightest neutralinos left over from the Big Bang, which we calculate using
standard assumptions, falls in the range favored by current determinations of
the Dark Matter density in the Universe. Already at a c.m. energy of 500 GeV,
SUSY particles can be accessible in some parameter range, and if the energy is
increased to $\sqrt{s} \simeq 1.2$ TeV, the $e^+e^-$ collider will have a reach
for high precision studies of SUSY particles in a range that is comparable to
the discovery range of the LHC.


title: QCD Analysis of Polarized Deep Inelastic Scattering Data

abstract:
  A QCD analysis of the world data on inclusive polarized deep inelastic
scattering of leptons on nucleons is presented in leading and next-to-leading
order. New parameterizations are derived for the quark and gluon distributions
and the value of $\alpha_s(M_Z)$ is determined. Emphasis is put on the
derivation of fully correlated error bands for these distributions which are
directly applicable to determine experimental errors of other polarized
observables. The impact of the variation of both the renormalization and
factorization scales on the value of $\alpha_s$ is studied. Finally a
factorization-scheme invariant QCD analysis based on the observables
$g_1(x,Q^2)$ and $d g_1(x,Q^2)/d \log(Q^2)$ is performed in next-to-leading
order, which is compared to the standard analysis.


title: Calculation of $\bar{\alpha}_{\rm Q.E.D.}$ on the Z

abstract:
  We perform a new, detailed calculation of the hadronic contributions to the
running electromagnetic coupling, $\bar{\alpha}$, defined on the Z particle (91
GeV). We find for the hadronic contribution, including radiative corrections,
$$10^5\times \deltav_{\rm had.}\alpha(M_Z^2)= 2740\pm12,$$ or, excluding the
top quark contribution, $$10^5\times \deltav_{\rm had.}\alpha^{(5)}(M_Z^2)=
2747\pm12.$$
  Adding the pure QED corrections we get a value for the running
electromagnetic coupling of $$\bar{\alpha}_{\rm Q.E.D.}(M_Z^2)=
{{1}\over{128.965\pm0.017}}.$$


title:
$J/\Psi$ suppression at SPS, RHIC and LHC energies and the percolation
  of strings

abstract:
  We study the enhancement of $c \bar c$ pair production that takes place in
central heavy ion collisions due to the formation of clusters of strings. These
clusters produce heavy flavors more efficiently due to their higher color. We
discuss the competition between this mechanism and the well-known screening of
color charge, which, above a critical string density, reduces strongly the
probability of binding these $c \bar c$ pairs to form $J/\Psi$ particles. The
dependence of $J/\Psi$ suppression on the centrality shows a peak at both RHIC
and LHC energies corresponding to the percolation critical density.


title: Sudakov effects in BBNS approach

abstract:
  The end-point singularity is an unsolved problem in BBNS approach.
Incorporating the partonic transverse momentum and the Sudakov form factor,
this problem can be solved model-independently. We discuss the Sudakov effects
in BBNS approach. The BBNS approach is compared with the modified PQCD
approach. The main idea of Sudakov form factor is briefly discussed. Our
conclusion is that the twist-3 contribution for the hard spectator scattering
is numerically not important in $B\to \pi\pi$ decays, compared with the twist-2
contribution.


title: New Hadrons Formed by the Fourth SM Family and Iso-singlet Quarks

abstract:
  The properties of new heavy mesons containing new heavy quarks have been
investigated. As an example, the fourth SM family quarks and weak isosinglet
quarks predicted by E_{6} GUT are considered. Production of these hadrons at
TeV energy lepton colliders have been analyzed.


title: Universal Singlets, Supergravity and Inflation

abstract:
  In supersymmetric theories, the occurrence of universal singlets is a
delicate issue, because they usually induce tadpoles that destabilize the
hierarchy. We study the effects of these tadpoles in supersymmetric hybrid
inflation models. The resulting scenario is generically modified, but it is
still possible to achieve inflation in a natural way. It is argued that
singlets, despite the problems associated with their presence, can lead to
interesting cosmological consequences.


title: Quark degrees of freedom in hadronic systems: Partonic distributions

abstract:
  The role of models in Quantum Chromodynamics is to produce simple physical
pictures that connect the phenomenological regularities with the underlying
structure. The static properties of hadrons have provided experimental input to
define a variety of very succesful Quark Models. We discuss applications of
some of the most widely used of these models to the high energy regime, a
scenario for which they were not proposed. The initial assumption underlying
our presentation will be that gluon and sea bremsstrahlung connect the
constituent quark momentum distributions with the partonic structure functions.
The results obtained are encouraging but lead to the necessity of more complex
structures at the hadronic scale. This initial hypothesis may be relaxed by
introducing some non perturbative model for the constituent quarks. Within this
scheme we will discuss some relevant problems in nucleon structure as seen in
high energy experiments.


title: On the massless contributions to the vacuum polarization of heavy quarks

abstract:
  Recently Groote and Pivovarov have given notice of a possible fault in the
use of sum rules involving two-point correlation functions to extract
information on heavy quark parameters, due to the presence of massless
contributions that invalidate the construction of moments of the spectral
densities. Here we show how to circumvent this problem through a new definition
of the moments, providing an infrared safe and consistent procedure.


title: Large Phases and CP Violation in SUSY

abstract:
  A brief overview is given of recent developments in the analyses of large
phases and CP violation in supersymmetric unified models. The problem of
experimental electric dipole moment constraints and large phases is discussed.
Implications of large phases on supersymmetric phenomena are reviewed. The
possibility of generating a muon electric dipole moment much larger than
implied by the scaling relation $d_{\mu}/d_e\simeq m_{\mu}/m_e$ from lepton
flavor nonuniversality and within reach of the recently proposed Brookhaven
experiment for a sensitive probe of $d_{\mu}$ is also discussed.


title: Radiation zeros in weak boson production processes at hadron colliders

abstract:
  The Standard Model amplitudes for processes where one or more gauge bosons
are emitted exhibit zeros in the angular distributions. The theoretical and
experimental aspects of these radiation amplitude zeros are reviewed and some
recent results are discussed. In particular, the zeros of the $WZ\gamma$ and
$WZZ$ production amplitudes are analyzed. It is briefly explained how radiation
zeros can be used to test the SM.


title: Muonium hyperfine structure and hadronic effects

abstract:
  A new result for the hadronic vacuum polarization correction to the muonium
hyperfine splitting (HFS) is presented:
  Delta nu(had - vp) = (0.233 +- 0.003) kHz.
  Compared with previous calculations, the accuracy is improved by using the
latest data on e+e- -> hadrons. The status of the QED prediction for HFS is
discussed.


title:
Hadronic Vacuum Polarization Contribution to the Muonium Hyperfine
  Splitting

abstract:
  We discuss hadronic effects in the muonium hyperfine structure and derive an
expression for the hadronic contribution to the hfs interval in form of the
one-dimensional integral of the cross section of e+e- annihilation into
hadrons. Higher-order hadronic contributions are also considered.


title: B -> X_s gamma in Supersymmetry with Explicit CP Violation

abstract:
  We discuss B -> X_s gamma decay in both constrained and unconstrained
supersymmetric models with explicit CP violation within the minimal flavor
violation scheme by including tan(beta) -enhanced large contributions beyond
the leading order. In this analysis, we take into account the relevant
cosmological and collider bounds, as well as electric dipole moment
constraints. In the unconstrained model, there are portions of the parameter
space yielding a large CP asymmetry at leading order (LO). In these regions, we
find that the CP phases satisfy certain sum rules, e.g., the sum of the phases
of the \mu parameter and the stop trilinear coupling centralize around \pi with
a width determined by the experimental bounds. In addition, at large values of
tan(beta), the sign of the CP asymmetry tracks the sign of the gluino mass, and
the CP asymmetry is significantly larger than the LO prediction. In the
constrained minimal supersymmetric standard model based on minimal
supergravity, we find that the decay rate is sensitive to the phase of the
universal trilinear coupling. This sensitivity decreases at large values of the
universal gauino mass. We also show that for a given set of the mass
parameters, there exists a threshold value of the phase of the universal
trilinear coupling which grows with tan(beta) and beyond which the experimental
bounds are satisfied. In both supersymmetric scenarios, the allowed ranges of
the CP phases are wide enough to have phenomenological consequences.


title: The sigma and rho in D and B decays

abstract:
  We study the D^{+} -> sigma pi^{+}, D^{+} -> rho^0 pi^{+}, B^{-} -> sigma
pi^{-}, B^{-} -> rho^0 pi^{-} and \bar{B}^0 -> rho^{\pm} pi^{\mp} decays in a
valence quark triangle model, incorporating chiral symmetries. We find a good
agreement with recent experimental data for D^{+} -> sigma pi^{+} and for D^{+}
-> rho^0 pi^{+}. We point out that a "long-distance" contribution due to the
axial vector a_1 meson pole, calculated by using chiral symmetry, can be
relevant to explain D^{+}-> rho^0 \pi^{+} and for lowering the ratio
R=Br(\bar{B}^0 -> rho^{\pm} pi^{\mp})/Br(B^{-} -> rho^0 pi^{-}) to be
consistent with its phenomenological determination, within the large
experimental uncertainity.


title: Gauge-Higgs Unification in Higher Dimensions

abstract:
  The electroweak Higgs doublets are identified as components of a vector
multiplet in a higher dimensional supersymmetric field theory. We construct a
minimal model in 6D where the electroweak $SU(2) \otimes U(1)$ gauge group is
extended to SU(3), and unified 6D models with the unified SU(5) gauge symmetry
extended to SU(6). In these realistic theories the extended gauge group is
broken by orbifold boundary conditions, leaving Higgs doublet zero modes which
have Yukawa couplings to quarks and leptons on the orbifold fixed points. In
one SU(6) model the weak mixing angle receives power law corrections, while in
another the fixed point structure forbids such corrections. A 5D model is also
constructed in which the Higgs doublet contains the fifth component of the
gauge field. In this case Yukawa couplings are introduced as non-local
operators involving the Wilson line of this gauge field.


title: Pion Physics at Low Energy and High Accuracy

abstract:
  The role of the quark condensate for the low energy structure of QCD is
discussed in some detail. In particular, the dependence of M_pi on m_u and m_d
and the low energy theorems for the pi-pi scattering amplitude are reviewed.
The new data on Ke4 decay beautifully confirm the standard picture, according
to which the quark condensate is the leading order parameter of the
spontaneously broken chiral symmetry.


title:
Supersymmetric corrections to Higgs decays and b-> s gamma for large tan
  beta

abstract:
  If tan beta is large, supersymmetric QCD corrections can become large,
putting naive perturbation theory into doubt. I show how these
tan-beta-enhanced corrections can be controlled to all orders in alpha_s
tanbeta. The result is shown for the decays H^+ -> t b-bar and b -> s gamma.


title: Radion Mediated Supersymmetry Breaking as a Scherk-Schwarz Theory

abstract:
  Recently, it has been demonstrated that radion mediated supersymmetry
breaking gives the same spectrum as Scherk-Schwarz supersymmetry breaking, and
can be interpreted as a dynamical realization of it. We make this connection
explicit by exhibiting the direct transformation from one theory to the other.
We then use the extreme UV softness of Scherk-Schwarz theories to calculate the
one-loop soft masses of matter fields. We do not find any cutoff sensitive
``Kaluza-Klein mediated'' contributions.


title: Doublet-Triplet Splitting and Fat Branes

abstract:
  We consider the doublet-triplet splitting problem in supersymmetric SU(5)
grand unified theory in five dimensions where the fifth dimension is
non-compact. We point out that an unnatural fine-tuning of parameters in order
to obtain the light Higgs doublets is not required due to the exponential
suppression of the overlap of the wave functions.


title:
Model with Gauge Coupling Unification 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
contains additional ${\bf 10 + \overline{10}}$, (${\bf 15 + \overline{15}}$)
and two ${\bf 24}$ Higgs multiplets in the non-supersymmetric SU(5) grand
unified theory. Although this model is non-supersymmetric theory, the gauge
coupling unification is realized due to the mass splittings of Higgs multiplets
by $S^1/(Z_2 \times Z_2')$ orbifolding. The constraints from the $b \to s
\gamma$, $\mu \to e \gamma$, and electron and muon anomalous magnetic moments
are also discussed.


title: Test of Factorization Hypothesis from Exclusive Non-leptonic B decays

abstract:
  We investigate the possibility of testing factorization hypothesis in
non-leptonic exclusive decays of B-meson. In particular, we considered the non
factorizable \bar{B^0} -> D^{(*)+} D_s^{(*)-} modes and \bar{B^0} -> D^{(*)+}
(\pi^-, \rho^-) known as well-factorizable modes. By taking the ratios
BR(\bar{B^0}-> D^{(*)+}D_s^{(*)-})/BR(\bar{B^0}-> D^{(*)+}(\pi^-,\rho^-)), we
found that under the present theoretical and experimental uncertainties there's
no evidence for the breakdown of factorization description to heavy-heavy
decays of the B meson.


title: Neutrino Mass Operator Renormalization Revisited

abstract:
  We re-derive the renormalization group equation for the effective coupling of
the dimension five operator which corresponds to a Majorana mass matrix for the
Standard Model neutrinos. We find a result which differs somewhat from earlier
calculations, leading to modifications in the evolution of leptonic mixing
angles and CP phases. We also present a general method for calculating
beta-functions from counterterms in MS-like renormalization schemes, which
works for tensorial quantities.


title: Superlight gravitinos in electron-photon collisions

abstract:
  Motivated by recent studies of supersymmetry in higher-dimensional spaces, we
discuss the experimental signatures of a superlight gravitino, mass < 0.001 eV.
We concentrate on the process (e- gamma -> selectronR gravitino) as a probe of
supersymmetry, where a single heavy superpartner and a superlight gravitino are
produced. The fact that there is only one heavy superpartner in the final state
in this process would require a lower center-of-mass energy for on-shell
production compared to conventional pair production. For instance, for a 500
GeV machine, we find that a positive signal will be found if the supersymmetry
breaking scale is less than about 2 TeV. If no positive signal is found, this
process puts a bound on the supersymmetry breaking scale.


title: B -> X_s l+ l- in the vectorlike quark model

abstract:
  We extend the standard model by adding an extra generation of isosinglet up-
and down-type quark pair which engage in weak interactions only via mixing with
the three ordinary quark families. It is shown that the generalized $4\times 4$
quark mixing matrix, which is necessarily nonunitary, leads to nonvanishing
flavor changing neutral currents. We then proceed to investigate various
distributions and total branching ratio of the inclusive B -> X_s l+ l- (l
=e,\mu) rare B decays in the context of this model. It is shown that the shapes
of the differential branching ratio and forward-backward asymmetry distribution
are very sensitive to the value of the model parameters which are constrained
by the experimental upper bound on BR(B -> X_s \mu^+ \mu^-). We also indicate
that, for certain values of the dileptonic invariant mass, CP asymmetries up to
10% can be obtained.


title: Dynamical Chaos and the Growth of Cosmological Fluctuations

abstract:
  I demonstrate that instability in a system of homogeneous scalar fields leads
to the growth of super-Hubble metric perturbations. This generalizes the result
that parametric resonance can lead to the growth of cosmological perturbations.
Since dynamical chaos is common in multi-field quartically coupled systems, I
argue that the evolution of the fields after inflation must be examined to
determine whether the amplitude of cosmological metric perturbations is
underestimated in the standard inflationary calculations. I illustrate this
effect with a simple hybrid inflation model.


title: Phenomenological Equations of State for the Quark-Gluon Plasma

abstract:
  Two phenomenological models describing an SU(N) quark-gluon plasma are
presented. The first is obtained from high temperature expansions of the free
energy of a massive gluon, while the second is derived by demanding color
neutrality over a certain length scale. Each model has a single free parameter,
exhibits behavior similar to lattice simulations over the range T_d - 5T_d, and
has the correct blackbody behavior for large temperatures. The N = 2
deconfinement transition is second order in both models, while N = 3,4, and 5
are first order. Both models appear to have a smooth large-N limit. For N >= 4,
it is shown that the trace of the Polyakov loop is insufficient to characterize
the phase structure; the free energy is best described using the eigenvalues of
the Polyakov loop. In both models, the confined phase is characterized by a
mutual repulsion of Polyakov loop eigenvalues that makes the Polyakov loop
expectation value zero. In the deconfined phase, the rotation of the
eigenvalues in the complex plane towards 1 is responsible for the approach to
the blackbody limit over the range T_d - 5T_d. The addition of massless quarks
in SU(3) breaks Z(3) symmetry weakly and eliminates the deconfining phase
transition. In contrast, a first-order phase transition persists with
sufficiently heavy quarks.


title:
Confinement and Chiral Symmetry Breaking via Domain-Like Structures in
  the QCD Vacuum

abstract:
  A qualitative mechanism for the emergence of domain structured background
gluon fields due to singularities in gauge field configurations is considered,
and a model displaying a type of mean field approximation to the QCD partition
function based on this mechanism is formulated. Estimation of the vacuum
parameters (gluon condensate, topological susceptibility, string constant and
quark condensate) indicates that domain-like structures lead to an area law for
the Wilson loop, nonzero topological susceptibility and spontaneous breakdown
of chiral symmetry. Gluon and ghost propagators in the presence of domains are
calculated explicitly and their analytical properties are discussed. The
Fourier transforms of the propagators are entire functions and thus describe
confined dynamical fields.


title: Revisiting W gamma production at RHIC

abstract:
  We discuss W gamma production in polarized p p collisions at RHIC energy. We
point out that the RHIC collider has two advantages over other hadron colliders
to measure the characteristic feature of W gamma production: (1) the RHIC
energy is not so high and (2) the polarized beams are available. We calculate
the tree level cross section for W gamma production using a generic spin basis
for W and discuss both the angular dependence and spin correlation.


title: Quintessence in a Brane World

abstract:
  We reanalyze a new quintessence scenario in a brane world model, assuming
that a quintessence scalar field is confined in our 3-dimensional brane world.
We study three typical quintessence models : (1) an inverse-power-law
potential, (2) an exponential potential, and (3) kinetic-term quintessence
($k$-essence) model. With an inverse power law potential model ($V(\phi) = \mu
^{\alpha + 4} \phi^{- \alpha}$), we show that in the quadratic dominant stage,
the density parameter of a scalar field $\Omega_\phi$ decreases as
$a^{-4(\alpha-2)/(\alpha+2)}$ for $2<\alpha < 6$, which is followed by the
conventional quintessence scenario. This feature provides us wider initial
conditions for a successful quintessence. In fact, even if the universe is
initially in a scalar-field dominant, it eventually evolves into a radiation
dominant era in the $\rho^2$-dominant stage.
  Assuming an equipartition condition, we discuss constraints on parameters,
resulting that $\alpha\geq 4$ is required. This constraint also restricts the
value of the 5-dimensional Planck mass, e.g. $4 \times 10^{-14}m_4 \lsim m_5
\lsim 3 \times 10^{-13}m_4$ for $\alpha=5$. For an exponential potential model
$V=\mu^4\exp(-\lambda \phi/m_4)$, we may not find a natural and successful
quintessence scenario as it is. While, for a kinetic-term quintessence, we find
a tracking solution even in $\rho^2$-dominant stage, rather than the
$\Omega_\phi$-decreasing solution for an inverse-power-law potential. Then we
do find a little advantage in a brane world. Only the density parameter
increases more slowly in the $\rho^2$-dominant stage, which provides a wider
initial condition for a successful quintessence.


title: Cosmological Constraint on the Zee model

abstract:
  It is well known that the Zee model induces small neutrino masses by
radiative corrections, where the bi-maximal flavor mixing is possible. We
analyze the cosmological condition in order for the baryon asymmetry generated
in the early universe not to be washed out in the
  Zee model. Since the lepton number is violated explicitly in the Zee model,
the baryon asymmetry might be washed out through the sphaleron processes
together with the lepton-number violating interactions. In this letter, we will
show that the baryon asymmetry is {\it not} washed out, although it has been
said that the Zee model cannot preserve the baryon asymmetry generated in the
early universe. This can be seen by considering an approximately conserved
number, $L' \equiv
  L_e-L_\mu-L_\tau$.


title:
Structure of the Coulomb and unitarity corrections to the cross section
  of $e^+e^-$ pair production in ultra-relativistic nuclear collisions

abstract:
  We analyze the structure of the Coulomb and unitarity corrections to the
single pair production as well as the cross section for the multiple pair
production. In the external field approximation we consider the probability of
$e^+e^-$ pair production at fixed impact parameter $\rho$ between colliding
ultra-relativistic heavy nuclei. We obtain the analytical result for this
probability at large $\rho$ as compared to the electron Compton wavelength. We
estimate also the unitary corrections to the total cross section of the
process.


title: Delocalization of the axial charge in the chiral limit

abstract:
  The nucleon's axial vector charge, g_A, becomes delocalized in the chiral
limit. When m_\pi = 0, and SU(2)_L x SU(2)_R is exact, 1/3 of the nucleon's
axial charge is to be found at infinite distance from the nucleon. For finite
m_\pi this result is approached smoothly as m_\pi -> 0. We illustrate this
effect by considering the lepton-proton spin-spin interaction arising from Z^0
exchange as a function of m_\pi. Delocalization may have implications for
lattice calculations of g_A and in nuclei.


title: Comments on multiple scattering of high-energy muons in thick layers

abstract:
  We describe two independent methods to calculate the angular distribution of
muons after traversing a thick scatterer due to multiple Coulomb scattering.
Both methods take into account the nuclear size effect. We demonstrate a
necessity to account for the nucleus extension as well as incoherent scattering
on atomic electrons to describe the muon scattering at large angles in thick
matter layers. The results of the two methods of calculations are in good
agreement.


title: Heavy-light current correlators at order $\alpha_s^2$ in QCD and HQET

abstract:
  The non-diagonal correlators of vector and scalar currents are considered at
three-loop order in QCD. The full mass dependence is computed in the case where
one of the quarks is massless and the other one carries mass $M$. We exploit
the decoupling relations between the full theory and the heavy quark effective
theory (HQET) in order to obtain the logarithmic parts of the leading threshold
terms. With the help of conformal mapping and Pad\'e approximation numerical
estimates for the non-logarithmic terms are extracted which in turn lead to a
prediction of the correlator in HQET at order $\alpha_s^2$. As applications of
the vector and scalar correlator we consider the single-top-quark production
via the process $q\bar{q}\to t\bar{b}$ and the decay rate of a charged Higgs
boson into hadrons, respectively. In both cases the computed NLO corrections
are shown to be numerically much less important than the leading ones. On the
contrary, the NLO order QCD corrections to the HQET sum rule for the leptonic
decay rate of a heavy-light meson proves to be comparable to the leading one.


title:
Bounds on tau neutrino magnetic moment and charge radius from Super-K
  and SNO observations

abstract:
  Neutrinos can scatter electrons in water detectors through their magnetic
moments and charge radii in addition to the charged and neutral currents
channels. The recent solar neutrino charged current event rates announced by
SNO with the earlier solar and atmospheric neutrino observations from
Super-Kamiokande allows us to put upper bounds of $\mu <10^{-9} \mu_B$ on
neutrino magnetic moments and $<r^2> < 10^{-31} cm^2$ on the neutrino charge
radii. For the electron and muon neutrinos these bounds are comparable with
existing bounds but for tau neutrinos these bounds are three orders of
magnitude more stringent than earlier terrestrial bounds. These bounds are
independent of any specific model of neutrino oscillations.


title: Experimental study of Pomeron

abstract:
  A Pomeron phenomenon remains a mystery. A short review of the experimental
situation in diffractive physics and an account of some spectacular
manifestations of the Pomeron are given.


title: Neutrino masses from operator mixing

abstract:
  We show that in theories that reduce, at the Fermi scale, to an extension of
the standard model with two doublets, there can be additional dimension five
operators giving rise to neutrino masses. In particular there exists a singlet
operator which can not generate neutrino masses at tree level but generates
them through operator mixing. Under the assumption that only this operator
appears at tree level we calculate the neutrino mass matrix. It has the Zee
mass matrix structure and leads naturally to bimaximal mixing. However, the
maximal mixing prediction for solar neutrinos is very sharp even when higher
order corrections are considered. To allow for deviations from maximal mixing a
fine tuning is needed in the neutrino mass matrix parameters. However, this
fine tuning relates the departure from maximal mixing in solar neutrino
oscillations with the neutrinoless double beta decay rate.


title: Gauge Unification In Six Dimensions

abstract:
  We study the breaking of a supersymmetric SO(10) GUT in 6 dimensions by
orbifold compactification. In 4 dimensions we obtain a N=1 supersymmetric
theory with the standard model gauge group enlarged by an additional U(1)
symmetry. The 4-dimensional gauge symmetry is obtained as intersection of the
Pati-Salam and the Georgi-Glashow subgroups of SO(10), which appear as unbroken
subgroups in the two 5 dimensional subspaces, respectively. The doublet-triplet
splitting arises as in the recently discussed SU(5) GUTs in 5 dimensions.


title: Progress in weakly coupled string phenomenology

abstract:
  The weakly coupled vacuum of $E_8\otimes E_8$ heterotic string theory remains
an attractive scenario for particle physics. The particle spectrum and the
issue of dilaton stabilization are reviewed. A specific model for hidden sector
condensation and supersymmetry breaking, that respects known constraints from
string theory, is described, and its phenomenological and cosmological
implications are discussed.


title: Sensitivity to the KARMEN Timing Anomaly at MiniBooNE

abstract:
  We present sensitivities for the MiniBooNE experiment to a rare exotic pion
decay producing a massive particle, Q^0. This type of decay represents one
possible explanation for the timing anomaly reported by the KARMEN
collaboration. MiniBooNE will be able to explore an area of the KARMEN signal
that has not yet been investigated.


title:
Information on $B \to \pi \pi$ Provided by the Semileptonic Process $B
  \to \pi l \nu$

abstract:
  Analysis of the present data on the semileptonic process $B \to \pi \ell \nu$
indicates that they have not yet reached the precision to provide adequate
information on the $B \to \pi$ form factor $F_+(q^2)$, which for $q^2 =
m_\pi^2$ is known to be related to the factorized color-favored (``$T$'', or
``tree'') contribution to $B^0 \to \pi^+ \pi^-$. It is shown here that with
around 500 $B \to \pi \ell \nu$ events in which rate and spectrum are measured
one can improve the accuracy of $T$ by a significant amount. A recent CLEO
determination of the $D^* D \pi$ coupling constant is compared with an earlier
prediction, and its role in the description of the $B \to \pi$ form factors is
noted. When combined with an estimate of the penguin amplitude (``$P$'')
obtained using flavor SU(3) symmetry from $B \to K \pi$ decays, information on
$T$ allows one to gauge the effects of the penguin amplitude on extraction of
the weak phase $\alpha = \phi_2$ from the time-dependent CP-violating rate
asymmetry in $B^0 \to \pi^+ \pi^-$. The constraint on $\alpha$ implied by a
recent experimental result on this asymmetry is described.


title: Quark-Hadron Duality for Hybrid Mesons at Large-Nc

abstract:
  We investigate implications of quark-hadron duality for hybrid mesons in the
large-Nc limit. A simple formalism is developed which implements duality for
QCD two-point functions of currents of quark bilinears, with any number of
gluons. We argue that the large-Nc meson masses share a common parameter, which
is related to the QCD string tension. This parameter is fixed from correlators
of conserved vector and axial-vector currents, and using lattice QCD
determinations of the string tension. Our results predict towers of hybrid
mesons which, within expected 1/Nc corrections, naturally accommodate the
1^(-+) experimental hybrid candidates.


title:
Complete High Temperature Expansions for One-Loop Finite Temperature
  Effects

abstract:
  We develop exact, simple closed form expressions for partition functions
associated with relativistic bosons and fermions in odd spatial dimensions.
These expressions, valid at high temperature, include the effects of a
non-trivial Polyakov loop and generalize well-known high temperature
expansions. The key technical point is the proof of a set of Bessel function
identities which resum low temperature expansions into high temperature
expansions. The complete expressions for these partition functions can be used
to obtain one-loop finite temperature contributions to effective potentials,
and thus free energies and pressures.


title:
Extraction of Polarized Gluon Distributions from Large-pt Light Hadron
  Pair Production

abstract:
  We propose a new formula for extracting the polarized gluon distribution from
the large-$p_T$ light hadron pair production for semi-inclusive processes in
polarized deep inelastic scattering. In general, a large-$p_T$ hadron pair is
produced via photon-gluon fusion(PGF) and QCD Compton at the lowest order of
QCD. The PGF gives us a direct information on $\Delta g$ in the nucleon, while
QCD Compton becomes background to the signal process for extracting $\Delta g$.
We show that the contribution from this background, i.e. the QCD Compton
process, can be removed by using symmetry relation among fragmentation
functions and taking an appropriate combination of various light hadron pair
production processes, and thus the double spin asymmetry can be described in
terms of $\Delta g/g$ alone.


title:
Sneutrino-Antisneutrino Mixing and Neutrino Mass in Anomaly--mediated
  Supersymmetry Breaking Scenario

abstract:
  In supersymmetric models with nonzero Majorana neutrino mass, the sneutrino
and antisneutrino mix, which may lead to same sign dilepton signals in future
collider experiments. We point out that the anomaly-mediated supersymmetry
breaking scenario has a good potential to provide an observable rate of such
signals for the neutrino masses suggested by the atmospheric and solar neutrino
oscillations. The sneutrino mixing rate is naturally enhanced by
m_{3/2}/m_{\tilde{\nu}}={\cal O}(4\pi/\alpha) while the sneutrino decay rate is
small enough on a sizable portion of the parameter space. We point out also
that the sneutrino-antisneutrino mixing can provide much stronger information
on some combinations of the neutrino masses and mixing angles than neutrino
experiments.


title: Characteristics of graviton-induced bremsstrahlung

abstract:
  We discuss Bremsstrahlung induced by graviton exchange in proton-proton
interactions at hadronic colliders, resulting from gg\to G\to \mu^+\mu^-\gamma.
Both the ADD and RS scenarios are discussed. Due to the coupling of the
graviton to two photons, the cross section has a new kinematical singularity
for hard photons. Thus, graviton-induced Bremsstrahlung tends to yield more
hard photons than QED-based Bremsstrahlung. As compared with the corresponding
two-body final state, \mu^+\mu^-, the cross section is, for realistic cuts,
smaller by a factor \sim 0.02. At the LHC, and with a string scale of a few TeV
(ADD scenario), or a graviton mass of a few TeV (RS scenario), a few events of
high invariant mass are expected per year.


title: Gluon-fusion contributions to Higgs plus two-jet production

abstract:
  Real emission corrections to Higgs production via gluon fusion, at order
alpha_s^4, lead to a Higgs plus two-jet final state. We present the calculation
of these scattering amplitudes, as induced by top-quark triangle-, box- and
pentagon-loop diagrams. These diagrams are evaluated analytically for arbitrary
top mass m_t. We study the renormalization and factorization scale-dependence
of the resulting H + 2 jet cross section, and discuss phenomenologically
important distributions at the LHC. The gluon fusion results are compared to
expectations for weak-boson fusion cross sections.


title: On a clean determination of $\phi_2$

abstract:
  We point out that time dependent study of four decay modes $B^0(t)\to \Dbar
K_S$, $B^0(t)\to D K_S$ $\Bbar^0(t)\to \Dbar K_S$, and $\Bbar^0(t)\to D K_S$
allows us to measure $\sin(\phi_1-\phi_2)$ - contrary to previously obtained
result that it measures $\sin(2\phi_1+\phi_3)$. The time dependent study of
$B_s^0(t)\to D^\pm_sK^\mp$, and the study of $B^-\to K^-(D,\Dbar)\to K^-f$
decay where $D\to f$ is a doubly Cabibbo suppressed decay yield information on
$\phi_3$, as previusly expected.


title:
On the stability of nontopological solitons in supersymmetric extensions
  of the Standard Model: A Numerical Approach

abstract:
  In various supersymmetric extensions of the Standard Model there appear
non-topological solitons due to the existence of U(1) global symmetries
associated with Baryon and/or Lepton quantum numbers. Trilinear couplings
(A-terms) in the scalar potential break explicitly the U(1) invariance. We
investigate numerically the stability of these objects in the case that this
breaking is small. We find that stable configurations, oscillating though, can
still appear. Other relevant properties are also examined.


title: Developments in Deep-inelastic Structure Function Calculations

abstract:
  We review recent developments in the calculation of deep-inelastic structure
functions to next-to-next-to leading order in perturbative QCD. We discuss the
impact of these corrections on the determination of the strong coupling alpha_s
and the parton distributions.


title: Finite baryon density effects on gauge field dynamics

abstract:
  We discuss the effective action for QCD gauge fields at finite temperatures
and densities, obtained after integrating out the hardest momentum scales from
the system. We show that a non-vanishing baryon density induces a charge
conjugation (C) odd operator to the gauge field action, proportional to the
chemical potential. Even though it is parametrically smaller than the leading C
even operator, it could have an important effect on C odd observables. The same
operator appears to be produced by classical kinetic theory, allowing in
principle for a non-perturbative study of such processes.


title:
Nucleus polarizability contribution to the hydrogen-deuterium isotope
  shift

abstract:
  The correction to the hydrogen-deuterium isotope shift due to the proton and
deuteron polarizability is evaluated on the basis of modern experimental data
on the structure functions of inelastic lepton-nucleus scattering. The
numerical value of this contribution is equal 63\pm 12 Hz.


title: Color-flavor locked strangelets

abstract:
  Finite lumps of color-flavor locked strange quark matter (CFL-strangelets)
are significantly more stable than strangelets without color-flavor locking for
wide ranges of parameters, increasing the likelihood of strangelet
metastability, or even absolute stability beyond some minimum baryon number
$A_{min}$. Whereas bulk CFL strange quark matter is electrically neutral,
CFL-strangelets are positively charged, with $Z\approx 0.3 A^{2/3}$. This is
quite different from ``ordinary'' strangelets and may provide a possible test
of color-flavor locking if strangelets are detected in upcoming cosmic-ray
space experiments.


title: Correlation of B_s -> mu^+ mu^- and (g-2)_mu in Minimal Supergravity

abstract:
  We analyse the rare decay mode B_s -> mu^+ mu^- in the minimal supergravity
scenario (mSUGRA). We find a strong correlation with the muon anomalous
magnetic moment (g-2)_mu. An interpretation of the recently measured excess in
(g-2)_mu in terms of mSUGRA corrections implies a substantial supersymmetric
enhancement of the branching ratio Br(B_s -> mu^+ mu^-): if (g-2)_mu exceeds
the Standard Model prediction by 4*10^{-9}, Br(B_s -> mu^+ mu^-) is larger by a
factor of 10-100 than in the Standard Model and within reach of Run-II of the
Tevatron. Thus an experimental search for B_s -> mu^+ mu^- is a stringent test
of the mSUGRA GUT scale boundary conditions. If the decay B_s -> mu^+ mu^- is
observed at Run-II of the Tevatron, then we predict the mass of the lightest
supersymmetric Higgs boson to be less than 120 GeV. The decay B_s -> mu^+ mu^-
can also significantly probe the favoured parameter range in SO(10) SUSY GUT
models.


title:
Addendum to: "On the anomalous dimension for the transversity
  distribution"

abstract:
  We review the results of our previous publication [Phys. Rev. D63, 116001
(2001); hep-ph/0012226] in the light of recent calculations and comments.


title: Axion and neutrino physics from anomaly cancellation

abstract:
  It has been recently shown that the requirement of anomaly cancellation in a
(non-supersymmetric) six-dimensional version of the standard model fixes the
field content to the known three generations. We discuss the phenomenological
consequences of the cancellation of the local anomalies: the strong CP problem
is solved and the fundamental scale of the theory is bounded by the physics of
the axion. Neutrinos acquire a mass in the range suggested by atmospheric
experiments.


title: Diquark Condensate in QCD with Two Colors at Next-to-Leading Order

abstract:
  We study QCD with two colors and quarks in the fundamental representation at
finite baryon density in the limit of light quark masses. In this limit the
free energy of this theory reduces to the free energy of a chiral Lagrangian
which is based on the symmetries of the microscopic theory. In earlier work
this Lagrangian was analyzed at the mean field level and a phase transition to
a phase of condensed diquarks was found at a chemical potential of half the
diquark mass (which is equal to the pion mass). In this article we analyze this
theory at next-to-leading order in chiral perturbation theory. We show that the
theory is renormalizable and calculate the next-to-leading order free energy in
both phases of the theory. By deriving a Landau-Ginzburg theory for the order
parameter we show that the finite one-loop contribution and the next-to-leading
order terms in the chiral Lagrangian do not qualitatively change the phase
transition. In particular, the critical chemical potential is equal to half the
next-to-leading order pion mass, and the phase transition is second order.


title: Top Quark Seesaw, Vacuum Structure and Electroweak Precision Constraints

abstract:
  We present a complete study of the vacuum structure of Top Quark Seesaw
models of the Electroweak Symmetry Breaking, including bottom quark mass
generation. Such models emerge naturally from extra dimensions. We perform a
systematic gap equation analysis and develop an improved broken phase
formulation for including exact seesaw mixings. The composite Higgs boson
spectrum is studied in the large-N_c fermion-bubble approximation and an
improved renormalization group approach. The theoretically allowed parameter
space is restrictive, leading to well-defined predictions. We further analyze
the electroweak precision constraints. Generically, a heavy composite Higgs
boson with a mass of ~1TeV is predicted, yet fully compatible with the
precision data.


title: QCD Sum-Rule Bounds on the Light Quark Masses

abstract:
  QCD sum-rules are related to an integral of a hadronic spectral function, and
hence must satisfy integral inequalities which follow from positivity of the
spectral function. Development of these Holder inequalities and their
application to the Laplace sum-rule for pions lead to a lower bound on the
average of the non-strange 2 GeV light-quark masses in the MS-bar scheme.


title:
Probing neutrino non-standard interactions with atmospheric neutrino
  data

abstract:
  We have reconsidered the atmospheric neutrino anomaly in light of the laetst
data from Super-Kamiokande contained events and from Super-Kamiokande and MACRO
up-going muons. We have reanalysed the proposed solution to the atmospheric
neutrino anomaly in terms of non-standard neutrino-matter interactions (NSI) as
well as the standard nu_mu -> nu_tau oscillations (OSC). Our statistical
analysis shows that a pure NSI mechanism is now ruled out at 99%, while the
standard nu_mu -> nu_tau OSC mechanism provides a quite remarkably good
description of the anomaly. We therefore study an extended mechanism of
neutrino propagation which combines both oscillation and non-standard
neutrino-matter interactions, in order to derive limits on flavour-changing
(FC) and non-universal (NU) neutrino interactions. We obtain that the
off-diagonal flavour-changing neutrino parameter epsilon and the diagonal
non-universality neutrino parameter epsilon' are confined to -0.03 < epsilon <
0.02 and |epsilon'| < 0.05 at 99.73% CL. These limits are model independent and
they are obtained from pure neutrino-physics processes. The stability of the
neutrino oscillation solution to the atmospheric neutrino anomaly against the
presence of non-standard neutrino interactions establishes the robustness of
the near-maximal atmospheric mixing and massive-neutrino hypothesis. The best
agreement with the data is obtained for Delta_m^2 = 2.3*10^{-3} eV^2,
sin^2(2*theta) = 1, epsilon = 6.7*10^{-3} and epsilon' = 1.1*10^{-3}, although
the chi^2 function is quite flat in the epsilon and epsilon' directions for
epsilon, epsilon' -> 0.


title:
Proton polarizability contribution to the hyperfine splitting in muonic
  hydrogen

abstract:
  The contribution of the proton polarizability to the ground state hyperfine
splitting in muonic hydrogen is evaluated on the basis of modern experimental
and theoretical results on the proton polarized structure functions. The value
of this correction is equal to 4.6(8)\cdot 10^{-4} times the Fermi splitting
E_F.


title:
Anomalous Anti-proton to Negative Pion Ratio as Revealed by Jet
  Quenching at RHIC

abstract:
  We study the apparent discrepancy between the standard PQCD predictions for
the meson and baryon ratios and multiplicities at moderate high $p_{T} > 2$ GeV
and recent experimental measurements in $Au+Au$ collisions at
$\sqrt{s}_{NN}=130$ GeV at the Relativistic Heavy Ion Collider (RHIC). We show
that the differences, most pronounced in central collisions, can be explained
by a strong non-perturbative baryon Junction component, which dominates the
currently accessible experimental $p_{T}$ window and the non-abelian energy
loss of fast partons propagating through hot and dense medium. The recently
introduced two component hybrid model, which combines a quenched jet PQCD
calculation in the Gyulassy-Levai-Vitev (GLV) formalism and a phenomenological
"soft" part, is further elaborated to take into account the full 3D expansion
in the pre-hadronization phase and include particle flavor dependent "soft"
inverse slopes as suggested by the baryon Junction picture. We show that such
approach can resolve what seems to be a factor of $\simeq 2$ difference in the
moderate high $p_{T}$ suppression of $\pi^0$ and $h^-$ as recently reported by
the PHENIX collaboration. The observed quenching of the high $p_{T}$ particle
spectra and the large $\bar{p}/\pi^-$ and $p/\pi^+$ ratios as a function of
$p_{T}$ are found to be consistent with a creation of a deconfined phase and
non-abelian energy loss of fast partons in a plasma of initial gluon rapidity
density $dN^g/dy \sim 1000$.


title: Photon-pair conversion into neutrinos in a strong magnetic field

abstract:
  A general analysis of the three-vertex loop amplitude in a strong magnetic
field, based on the asymptotic form of the electron propagator in the field, is
performed. In order to investigate the photon-neutrino process gamma gamma ->
nu bar nu, the vertex combinations of the scalar-vector-vector (SVV),
pseudoscalar-vector-vector (PVV), 3-vector (VVV), and
axial-vector-vector-vector (AVV) types are considered. It is shown that only
the SVV amplitude grows linearly with the magnetic field strength, while in the
other amplitudes, PVV, VVV, and AVV, the linearly growing terms are cancelled.
The process gamma gamma -> nu bar nu is investigated in the
left-right-symmetric extension of the standard model of electroweak
interaction, where the effective scalar nu nu e e coupling could exist.
Possible astrophysical manifestations of the considered process are discussed.


title: Fast simulation of the Cherenkov light from showers

abstract:
  A method for fast simulation of the Cherenkov light generated by
electromagnetic showers is described. The parametrization for the longitudinal
profile is used and fluctuations and correlations of the parameters are taken
into account in a consistent way. Our method dramatically reduces the CPU time
and its results are in a rather good agreement with a full Monte Carlo
simulation.


title: T-violating effects in three flavor neutrino oscillations in matter

abstract:
  In this talk, we consider the interplay of fundamental and matter-induced
T-violating effects in neutrino oscillations in matter. We present a simple
approximative analytical formula for the T-violating probability asymmetry for
three flavor neutrino oscillations in matter with an arbitrary density profile.
We also discuss some implications of the obtained results. Since there are no
T-violating effects in two flavor neutrino case (in the limit of vanshing
$\theta_{13}$ or $\Delta m_{21}^2$, the three flavor neutrino oscillations
reduces to the two flavor ones), the T-violating probability asymmetry can, in
principle, provide a way to measure $\theta_{13}$ and $\Delta m_{21}^2$.


title: Proton stability in 5D GUTs with orbifold compactification

abstract:
  We construct SU(5) SUSY GUT in 5D compactified on S^1/Z_2 orbifold where the
matter fields are living in the five dimensional bulk. SU(5) symmetry is broken
down to the Standard Model gauge group by the orbifold projection which
automatically ensures stability of proton in all orders of perturbation theory.
The model predicts extra mirror quark-lepton families which along with the GUT
particles and the excitations of extra dimensions could be observable at high
energy colliders providing the unification scale is in the TeV range.


title:
Clustering, Anisotropy, Spectra of Ultra High Energy Cosmic Ray:
  Finger-prints of Relic Neutrinos Masses in Dark Halos

abstract:
  The Ultra High Energy Cosmic Ray UHECR, by UHE neutrino-relic neutrino Z
showering in Hot Dark Halos HDM, should exhibits an energy spectra and an
anisotropy reflecting (also) the relic neutrino masses and their hierarchical
HDM halo clustering. A twin light neutrino mass splitting may reflect to twin Z
resonance and into a complex UHECR spectra modulation, a twin bump, at the edge
at highest GZK energy cut-off. Each possible neutrino mass associates a
characteristic dark halo size (galactic, local, Super Cluster) and its local
anisotropy due to our peculiar position within that dark matter distribution. A
neutrino HDM halo around a Mpc will allow to the UHECR neutron secondary
component at E_n> 10^{20} eV (due to Z decay) to arise playing a role
comparable with the charged p- anti{p} ones. Their un-deflected n-anti{n} (or
decayed p-anti{p}) flight is shorter leading to a prompt and hard UHECR trace
pointing toward the original UHECR source direction. The direct p -anti{p}
pairs are split and spread by random magnetic fields into a more diluted and
smeared UHECR signal around the original source direction. TeVs signals by
synchrotron radiation must also mark the Z-WW Showering. The UHE Neutrino- Z
showering signatures may be already found in recent (and future) events in
AGASA (and Auger) data. The observed hard doublet and triplets spectra, their
time and space clustering already favour the rising key role of UHECR neutron
secondaries originated by Z tail shower.


title: A mirror world explanation for the Pioneer spacecraft anomalies?

abstract:
  We show that the anomalous acceleration of the Pioneer 10/11 spacecraft can
be explained if there is some mirror gas or mirror dust in our solar system.


title:
The phenomenology of neutrinos with Majorana mass terms and
  standard-model interactions derived in the charge-parity basis

abstract:
  (abridged) The physical mechanisms that make a neutrino with standard-model
(SM) weak interactions a "lepton-number conservation (LNC) violating" neutrino
such as the Majorana neutrino are analysed in a basis of two Majorana states
that have opposite charge-parity ("charge-parity basis"). A small Majorana mass
that is larger than any Dirac mass makes the neutrino not a Majorana but a
"pseudo-Majorana" particle that has no definite chirality and therefore has a
different phenomenology than the physical neutrino. A combination of a large
Majorana and Dirac mass of nearly equal value makes the neutrino a Majorana
neutrino. However if this Majorana neutrino has SM interactions, its weak
transition amplitudes squared are a factor 2 smaller than the ones observed for
the physical neutrino. Only with a small Dirac mass that is larger than any
Majorana mass (and in the massless case), the physical neutrino's phenomenology
is correctly predicted by the SM. Such a mass combination makes the neutrino a
Dirac- or (the most likely possibility for the physical neutrino) Pontecorvo's
pseudo-Dirac particle which features neutrino-antineutrino oscillations, that
violate LNC. Pseudo-Dirac neutrinos enable a completely negligible rate for
neutrinoless double-beta decay if there is no Majorana-mass independent decay
mechanism. Off-diagonal components of the mass matrix in the charge-parity
basis make the neutrino a mixture of Dirac field with a different particle and
anti-particle mass (i.e. a mass that violates CPT invariance) and a
pseudo-Dirac field. Such a neutrino leads to a phenomenology similar to the one
with additional generations of sterile neutrinos.


title: Unitary and Analytic Models in Particle Physics Phenomenology

abstract:
  After two decades of a development of the unitary and analytic models of the
electromagnetic structure of hadrons and nuclei their main principles are
briefly formulated, then a general scheme of their applications to the
electromagnetic, weak and strong interaction processes are traced out and
finally, some results of their successful applications are reviewed.


title: Hadronic B Decays to Charmless VT Final States

abstract:
  Charmless hadronic decays of B mesons to a vector meson (V) and a tensor
meson (T) are analyzed in the frameworks of both flavor SU(3) symmetry and
generalized factorization. We also make comments on B decays to two tensor
mesons in the final states. Certain ways to test validity of the generalized
factorization are proposed, using $B \to VT$ decays. We calculate the branching
ratios and CP asymmetries using the full effective Hamiltonian including all
the penguin operators and the form factors obtained in the non-relativistic
quark model of Isgur, Scora, Grinstein and Wise.


title:
Fragmentation functions from semi-inclusive DIS pion production and
  implications for the polarized parton densities

abstract:
  By combining recent HERMES data on semi-inclusive DIS $\pi^\pm$-production
with the singlet fragmentation function $D_\Sigma^{\pi^+}$, which is well
determined from $e^+e^-$ data, we are able to extract, for the first time, the
flavoured fragmentation functions $D_u^{\pi^+}$, $D_d^{\pi^+}$ and
$D_s^{\pi^+}$ without making any assumptions about favoured and unfavoured
transitions. Whereas $D_u^{\pi^+}$ and $D_d^{\pi^+}$ are very well determined,
the accuracy of $D_s^{\pi^+}$ is limited by the uncertainty in evolving
$D_\Sigma^{\pi^+}$ from the $Z^0$ pole down to the SIDIS scale of a few
$(GeV)^2$. We discuss how the precision on $D_s^{\pi^+}$ could be improved.
Knowledge of the $D_{q=u,d,s}^{\pi^+}$ will permit the extraction of the
polarized parton densities from future polarized SIDIS asymmetry measurements.
We study the precision that can be expected in such an extraction.


title:
Effects of SO(10) D-Term on Yukawa Unification and Unstable Minima of
  the Supersymmetric Scalar Potential

abstract:
  We study the effects of SO(10) D-terms on the allowed parameter space (APS)
in models with $t - b - \tau$ and $b - \tau$ Yukawa unifiction. The former is
allowed only for moderate values of the D-term, if very precise ($\le$ 5%)
unification is required. Next we constrain the parameter space by looking for
different dangerous directions where the scalar potential may be unbounded from
below (UFB1 and UFB3). The common trilinear coupling $A_0$ plays a significant
role in constraing the APS. For very precise $t - b - \tau$ Yukawa unification,
$-m_{16} < or \approx A_0 < or \approx m_{16}$ can be probed at the LHC, where
$m_{16}$ is the common soft breaking mass for the sfermions. Moreover, an
interesting mass hierarchy with very heavy sfermions but light gauginos, which
is strongly disfavoured in models without D-terms, becomes fairly common in the
presence of the D-terms. The APS exhibits interesting characteristics if
$m_{16}$ is not the same as the soft breaking mass $m_{10}$ for the Higgs
sector. In $b - \tau$ unification models with D-terms, the APS consistent with
Yukawa unification and radiative electroweak symmetry breaking, increases as
the UFB1 constraint becomes weaker. However for $A_0 \leq 0$, a stronger UFB3
condition still puts, for a given $m_{16}$, a stringent upper bound on the
common gaugino mass ($m_{1/2}$) and a lower bound on $m_{16}$ for a given
$m_{1/2}$. The effects of sign of $\mu$ on Yukawa unification and UFB
constraints are also discussed.


title:
Semi-Simple Unification on T^6/Z_12 Orientifold in the Type IIB
  Supergravity

abstract:
  The semi-simple unification model based on SU(5)_GUT \times U(3)_H gauge
group is an interesting extension of the minimal SU(5)_GUT grand unification
theory (GUT), since it solves the two serious problems in the standard GUT: the
triplet-doublet splitting problem and the presence of dangerous dimension five
operators for proton decay. Here, the extra U(3)_H gauge interaction plays a
crucial role on the GUT breaking. In this paper, we show that the full
multiplet structure of the U(3)_H sector required for the desired GUT breaking
is reproduced naturally on T^6/Z_12 orientifold in the type IIB supergravity
with a D3-D7 system. The SU(5)_GUT vector multiplet lives on D7-branes and the
U(3)_H sector resides on D3-branes. We also show that various interesting
features in the original SU(5)_GUT \times U(3)_H model are explained in the
present brane-world scenario. A possible extension to the type IIB string
theory is also discussed.


title: Cluster Percolation and First Order Phase Transitions in the Potts Model

abstract:
  The q-state Potts model can be formulated in geometric terms, with
Fortuin-Kasteleyn (FK) clusters as fundamental objects. If the phase transition
of the model is second order, it can be equivalently described as a percolation
transition of FK clusters. In this work, we study the percolation structure
when the model undergoes a first order phase transition. In particular, we
investigate numerically the percolation behaviour along the line of first order
phase transitions of the 3d 3-state Potts model in an external field and find
that the percolation strength exhibits a discontinuity along the entire line.
The endpoint is also a percolation point for the FK clusters, but the
corresponding critical exponents are neither in the Ising nor in the random
percolation universality class.


title:
The Higgs Boson Sector of the Complex MSSM in the Feynman-diagrammatic
  approach

abstract:
  In the Minimal Supersymmetric Standard Model with complex parameters (cMSSM)
we calculate higher order corrections to the Higgs boson sector in the
Feynman-diagrammatic approach using the on-shell renormalization scheme. The
application of this approach to the cMSSM, being complementary to existing
approaches, is analyzed in detail. Numerical examples for the leading fermionic
corrections, including the leading two-loop effects, are presented. Numerical
agreement within 10% with other approaches is found for small and moderate
mixing in the scalar top sector. The leading fermionic corrections,
supplemented by the full logarithmic one-loop and the leading two-loop
contributions are implemented into the public Fortran code FeynHiggsFastC.


title: String Balls at the LHC and Beyond

abstract:
  In string theory, black holes have a minimum mass below which they transition
into highly excited long and jagged strings --- ``string balls''. These are the
stringy progenitors of black holes; because they are lighter, in theories of
TeV-gravity, they may be more accessible to the LHC or the VLHC. They share
some of the characteristics of black holes, such as large production cross
sections. Furthermore, they evaporate thermally at the Hagedorn temperature and
give rise to high-multiplicity events containing hard primary photons and
charged leptons, which have negligible standard-model background.


title:
Power corrections of off-forward quark distributions and harmonic
  operators with definite twist

abstract:
  A group theoretical procedure for parametrizing non-forward matrix elements
of non-local QCD operators is introduced. The related (two-variable)
distribution amplitudes are given as sum over power corrections of the double
distributions. For totally symmetric (local) operators the infinite twist
decomposition is given completely and for operators with non-trivial symmetry
type up to twist 3. The power corrections for most of the phenomenological
relevant double distributions and the vector meson wave functions are
determined. They may be obtained, by harmonic extension, from the corresponding
operators or distribution amplitudes on the light-cone.


title: Proton Electro-Magnetic Form-Factors in the Instanton Liquid Model

abstract:
  We report the first non-perturbative calculation of proton electro-magnetic
form-factors in the Random Instanton Liquid Model (RILM) and in the Interacting
Instanton Liquid Model (IILM). By calculating the ratio of appropriate
three-point to two-point functions, we divide out the coupling constants and
compare our results directly to some integral of the form-factors. Using
various parameterizations of the electric form-factor $G_E(Q^2)$ at large
$Q^2>3.5 GeV^2$, where it is not yet measured, we compare those with expected
theoretical dependence. We find from this comparison that some distributions of
charge are clearly excluded (e.g. the same as of the magnetic moment, $\mu
G_E/G_M=1$, as well as the opposite scenario in which $\mu G_E/G_M$ rapidly
approach zero), restricting possible behavior of the form-factor to rather
narrow band.
  Furthermore, we found that our calculation of the nucleon form-factors is
dominated by a configuration in which two out of three quarks interact with a
$single$-instanton, in spite of the fact that the evaluated three-point
function has rather large distances ($\sim 1.2 fm$) between points. We also
estimate the size of the scalar di-quark and found it to be very small,
comparable to the typical instanton size.


title:
Theoretical implications of the possible observation of Higgs bosons at
  LEP

abstract:
  Theoretical implications of the possible observation of a Higgs boson with a
mass of about 115 GeV at LEP are discussed. Within the Standard Model a Higgs
boson in this mass range agrees well with the indirect constraints from
electroweak precision data. However, it would nevertheless point towards
physics beyond the Standard Model, in particular to Supersymmetric extensions.
The interpretation of the LEP excess as production of the light or the heavy
CP-even Higgs boson is discussed within the unconstrained MSSM and the mSUGRA,
GMSB and AMSB scenarios. Prospects for Higgs physics at future colliders are
briefly summarized.


title:
Blocking Active-Sterile Neutrino Oscillations in the Early Universe with
  a Majoron Field

abstract:
  We propose a new mechanism to block the active-sterile neutrino oscillations
in the Early Universe. We show that a typical consequence of theories where the
lepton number is spontaneously broken is the existence of a coherent
cosmological Majoron field with a strength proportional to the lepton and
baryon numbers of the Universe. This field interacts with leptons and changes
the potentials relevant for neutrino oscillations. If the scale of lepton
number symmetry breaking is of the order of 1 GeV then a Majoron field and
lepton number asymmetry of the order of the baryon asymmetry are strong enough
to block the active-sterile neutrino oscillations with the atmospheric neutrino
mass gap which otherwise would bring the sterile neutrino into equilibrium at
the big bang nucleosynthesis epoch.