title:
Technique for Direct eV-Scale Measurements of the Mu and Tau Neutrino
  Masses Using Supernova Neutrinos

abstract:
  Early black hole formation in a core-collapse supernova will abruptly
truncate the neutrino fluxes. The sharp cutoff can be used to make
model-independent time-of-flight neutrino mass tests. Assuming a neutrino
luminosity of $10^{52}$ erg/s per flavor at cutoff and a distance of 10 kpc,
SuperKamiokande can detect an electron neutrino mass as small as 1.8 eV, and
the proposed OMNIS detector can detect mu and tau neutrino masses as small as 6
eV. This {\it Letter} presents the first technique with direct sensitivity to
eV-scale mu and tau neutrino masses.

categories: hep-ph astro-ph gr-qc hep-ex nucl-ex nucl-th


title: Parapositronium Decay and Dispersion Relations

abstract:
  Positronium decay rates are computed at the one-loop level, using
convolution-type factorized amplitudes. The dynamics of this factorization is
probed with dispersion relations, showing that unallowed approximations are
usually made, and some ordre alpha^2 corrections missed. Further, we discuss
the relevance of the Schrodinger wavefunction as the basis for perturbative
calculations. Finally, we apply our formalism to the parapositronium two-photon
decay.


title:
E_6 unification model building II. Clebsch-Gordan coefficients of
  78$\otimes$78

abstract:
  We have computed the Clebsch-Gordan coefficients for the product (000001)
$\otimes$ (000001), where (000001) is the adjoint 78-dimensional representation
of $E_6$. The results are presented for the dominant weights of the irreducible
representations in this product. As a simple application we express the singlet
operator in $ 27 \otimes 78 \otimes \bar{27}$ in terms of multiplets of the
Standard Model gauge group.


title: Analytical Behaviour of Positronium Decay Amplitudes

abstract:
  Positronium annihilation amplitudes that are computed by assuming a
factorization approximation with on-shell intermediate leptons do not exhibit
good analytical behaviour. Using dispersion techniques, we find new
contributions that interfere with the known results to restore analytical
properties. Those new amplitudes which cannot be obtained using standard
factorized amplitude formalism, contribute at order alpha^2. Therefore they
have to be evaluated before any theoretical conclusion can be drawn upon the
orthopositronium lifetime puzzle.


title:
Dynamics of barrier penetration in thermal medium: exact result for
  inverted harmonic oscillator

abstract:
  Time evolution of quantum tunneling is studied when the tunneling system is
immersed in thermal medium. We analyze in detail the behavior of the system
after integrating out the environment. Exact result for the inverted harmonic
oscillator of the tunneling potential is derived and the barrier penetration
factor is explicitly worked out as a function of time. Quantum mechanical
formula without environment is modifed both by the potential renormalization
effect and by a dynamical factor which may appreciably differ from the
previously obtained one in the time range of 1/(curvature at the top of
potential barrier).


title:
Two Hagedorn temperatures: a larger one for mesons, a lower one for
  baryons

abstract:
  We show that the Hagedorn temperature obtained from experimental spectra is
larger for mesons than for baryons. Dual string models explain this behavior
asymptotically.


title:
The spin correlation in top quark production: QCD corrections vs
  anomalous couplings

abstract:
  We discuss top quark production and its subsequent decay at lepton colliders
including both QCD corrections and anomalous gamma / Z - t t-bar couplings. The
off-diagonal spin basis for the top and anti-top quarks is shown to be useful
to probe the anomalous couplings.


title: $B\to \pi \pi, K \pi$ Decays in QCD Improved Factorization Approach

abstract:
  Motivated by recent measurements, we investigate $B\to \pi \pi, K \pi$ decay
modes in the framework of QCD improved factorization, which was recently
proposed by Beneke $et al$. We find that all the measured branching ratios are
well accommodated in the reasonable parameter space except for $B\to K^0 \pi^0
$. We also discuss in detail the strong penguin contributions and the ${\cal
O}(\alpha_s)$ corrections to the chirally enhanced terms. We find that the weak
phase $\gamma$ lies in the region $120^{\circ}<\gamma<240^{\circ}$, which is
mainly constrained by $B\to \pi^- \pi^+ $.


title: Are charge fluctuations a good signal for QGP?

abstract:
  A recent proposal to study charge fluctuations as a possible signal of
quark-gluon plasma is discussed. It is shown that the "pion gas model"
considered as the reference sample is unrealistic and the expected signal from
plasma may be difficult to distinguish from that coming from "standard
collisions".


title:
Canonical Description of Strangeness Enhancement from p-A to Pb-Pb
  Collisions

abstract:
  We consider the production of strange particles in Pb-Pb and p-A collisions
at the SPS energy reported by the WA97 experiment. We show that the observed
enhancement of strange baryon and antibaryon yields in Pb-Pb collisions
relative to p-Be and p-Pb can be explained in terms of the statistical model
formulated in canonical ensemble with respect to strangeness conservation. The
importance and the role of strangeness under saturation is also discussed.


title:
Parton Distributions in the Virtual Photon Target and Factorization
  Scheme Dependence

abstract:
  We investigate parton distributions in the virtual photon target, both
polarized and unpolarized, up to the next-leading order (NLO) in QCD. Parton
distributions can be predicted completely up to NLO, but they are
factorization-scheme-dependent. We analyze parton distributions in several
factorization schemes and discuss their scheme dependence. Particular
attentions are paid to the axial anomaly effect on the first moments of the
polarized quark parton distributions, and also to the large-$x$ behaviors of
polarized and unpolarized parton distributions.


title:
Statistical treatment of detection cross-section uncertainties in the
  analysis of solar neutrino data

abstract:
  We propose a modification to the standard statistical treatment of the
detection cross-section uncertainties in the analysis of solar neutrino data.
We argue that the uncertainties of the energy-averaged cross sections of the
different neutrino fluxes in the same experiment should be treated as
correlated. We show that the resulting allowed regions for the neutrino
oscillation parameters are significantly larger than the ones obtained with
uncorrelated uncertainties.


title: Unbroken versus broken mirror world: a tale of two vacua

abstract:
  If the Lagrangian of nature respects parity invariance then there are two
distinct possibilities: either parity is unbroken by the vacuum or it is
spontaneously broken. We examine the two simplest phenomenologically consistent
gauge models which have unbroken and spontaneously broken parity symmetries,
respectively. These two models have a Lagrangian of the same form, but a
different parameter range is chosen in the Higgs potential. They both predict
the existence of dark matter and can explain the MACHO events. However, the
models predict quite different neutrino physics. Although both have light
mirror (effectively sterile) neutrinos, the ordinary-mirror neutrino mixing
angles are unobservably tiny in the broken parity case. The minimal broken
parity model therefore cannot simultaneously explain the solar, atmospheric and
LSND data. By contrast, the unbroken parity version can explain all of the
neutrino anomalies. Furthermore, we argue that the unbroken case provides the
most natural explanation of the neutrino physics anomalies (irrespective of
whether evidence from the LSND experiment is included) because of its
characteristic maximal mixing prediction.


title:
Elastic neutrino - electron scattering and potential effects of magnetic
  and electric dipole moments

abstract:
  We consider elastic neutrino - electron scattering of solar neutrinos with
magnetic moments and electric dipole moments, where the solar neutrino state at
the scattering site is determined by the evolution in matter and solar magnetic
fields of the initial electron neutrino state. We present the general cross
section for an arbitrary superposition of active and sterile neutrino types
with positive and negative helicities, with particular emphasis on the effect
of transverse polarization, which gives rise to an azimuthal asymmetry as a
function of the recoil electron momentum. Within our physically motivated
approximation, we perform a general CP analysis and show that in the 1-Dirac
and 2-Majorana neutrino cases no CP-violating effects are present, which means
that it is not possible to distinguish between magnetic and electric dipole
moments in these cases. We also study the consequences of neutrino energy
averaging on the cross section and stress that in the 2-Majorana neutrino case
this averaging leads to a suppression of the transverse neutrino polarization
effects.


title: SO(10)-Inspired See-Saw Mechanism

abstract:
  We determine the nu_{R} Majorana mass matrix from the experimental data on
neutrino oscillations in the framework of a see-saw SO(10) model, where we
impose the condition (M^R)_{33} = 0 to avoid too large fine-tunings in the
see-saw formula. We find a class of solutions with the two lowest neutrino
masses almost degenerate and the scale of the matrix elements of M^R in the
range 10^{11} -10^{12} GeV in agreement with Pati-Salam intermediate symmetry.
We find also solutions with smaller neutrino masses, for which the scale of M_R
depends on the solution to the "solar neutrino problem" and on the value of the
component of \nu_e along the highest mass eigenstate, U_{e3}.


title: Higgs and SUSY searches at future colliders

abstract:
  In this talk, I discuss some aspects of Higgs searches at future colliders,
particularly comparing and contrasting the capabilities of LHC and Next Linear
Collider (NLC), including the aspects of Higgs searches in supersymmetric
theories. After this, I will discuss how the search and study of sparticles
other than the Higgs can give information about the parameters of the Minimal
Supersymmetric Standard Model (MSSM).


title: Constraining New Physics with Vertex Corrections

abstract:
  We discuss how new physics not encompassed within the STU oblique correction
framework can be constrained from precision electroweak measurements via vertex
corrections to Z-pole observables.


title: CP Violation in Top Physics

abstract:
  CP violation in top physics is reviewed. The Standard Model has negligible
effects, consequently CP violation searches involving the top quark may
constitute the best way to look for physics beyond the Standard Model.
Non-standard sources of CP violation due to an extended Higgs sector with and
without natural flavor conservation and supersymmetric theories are discussed.
Experimental feasibility of detecting CP violation effects in top quark
production and decays in high energy e+ e-, gamma-gamma, mu+ mu-, pp and p-bar
p colliders are surveyed. Searches for the electric, electro-weak and the
chromo-electric dipole moments of the top quark in e+ e- -> t-bar t and in p p
-> t-bar t X are descibed. In addition, other mechanisms that appear promising
for experiments, e.g., tree-level CP violation in e+ e- -> t-bar t h, t-bar t
Z, t-bar t nu_e-bar nu_e and in the top decay t -> b tau nu_tau and CP
violation driven by s-channel Higgs exchanges in p p, gamma gamma, mu+ mu- ->
t-bar t etc., are also discussed.


title: Lorentz and CPT Tests in Atomic Systems

abstract:
  A review of Lorentz and CPT tests performed in atomic systems is presented. A
theoretical framework extending QED in the context of the standard model is
used to analyze a variety of systems. Experimental signatures of possible
Lorentz and CPT violation in these systems are investigated. Estimated bounds
attainable in future experiments and actual bounds obtained in recent
experiments are given.


title: Quark Hadron Continuity in QCD with one Flavor

abstract:
  We study QCD with one flavor at finite baryon density. In the limit of very
high baryon density the system is expected to be a color superconductor. In the
case of one flavor, the order parameter is in a $\bar 3$ of color and has total
angular momentum one. We show that in weak coupling perturbation theory, the
energetically preferred phase exhibits ``color-spin-locking'', i.e. the color
and spin direction of the condensate are aligned. We discuss the properties of
this phase and argue that it shares important features of the hadronic phase at
low density. In particular, we find an unbroken rotational symmetry, spin 3/2
quasiparticles, and an unusual mechanism for quark-anti-quark condensation. Our
results are relevant to three flavor QCD in the regime where the strange quark
mass is bigger than the critical value for color-flavor-locking. We find that
the gaps in this case are on the order of one MeV.


title: Note on tree-level unitarity in the General Two Higgs Doublet Model

abstract:
  Tree-level unitarity constraints on the masses of the Higgs bosons in the
general Two Higgs Doublet Model (THDM) are studied. We first consider the case
where the Higgs potential is invariant under a discrete symmetry
transformation, and derive strong constraints on the mass of the lightest
CP-even Higgs boson ($M_h$) as a function of $\tan\beta$. We then show that the
inclusion of the discrete symmetry breaking term weakens the mass bounds
considerably. It is suggested that a measurement of $M_h$ and $\tan\beta$ may
enable discrimination between the two Higgs potentials.


title: Flavour non-conservation in goldstino interactions

abstract:
  We point out that the interactions of goldstinos with matter supermultiplets
are a potential source of flavour violation, if fermion and sfermion mass
matrices are not aligned and supersymmetry is spontaneously broken at a low
scale. We study the impact of those couplings on low-energy processes such as
\mu \to e \gamma, \mu \to eee, K \to \mu^+ \mu^-, K-\ov{K} transitions and
analogous ones. Moreover, we address the issue of flavour violation in
low-energy processes involving two goldstinos and two matter fermions,
generalizing earlier results obtained in the flavour-conserving case.


title: Radion Mass is Milli-eV in the Goldberger-Wise Stabilization Mechanism

abstract:
  A complete calculation of the radion mass has been given by Tanaka and
Montes, hep-th/0001092, and also by Csaki, Graesser and Kribs (in preparation),
which both obtain the TeV-scale. It seems likely that the problem with our
computation was neglect of the back-reaction of the scalar field on the
graviton zero mode, and consequent contributions to the radion kinetic term
from the gravitational part of the Lagrangian. We thank T. Tanaka and C. Csaki
for pointing out their results to us.


title:
A Poincare-Covariant Parton Cascade Model for Ultrarelativistic
  Heavy-Ion Reactions

abstract:
  We present a new cascade-type microscopic simulation of nucleus-nucleus
collisions at RHIC energies. The basic elements are partons (quarks and gluons)
moving in 8N-dimensional phase space according to Poincare-covariant dynamics.
The parton-parton scattering cross sections used in the model are computed
within perturbative QCD in the tree-level approximation. The Q^2 dependence of
the structure functions is included by an implementation of the DGLAP mechanism
suitable for a cascade, so that the number of partons is not static, but varies
in space and time as the collision of two nuclei evolves. The resulting parton
distributions are presented, and meaningful comparisons with experimental data
are discussed.


title: N*, Lambda*, Sigma* and Xi* Resonances from J/Psi and Psi' Decays

abstract:
  Vector charmonium states $J/\Psi$ and $\Psi'$ are copiously produced by
$e^+e^-$ annihilations at the Beijing Electron Positron Collider (BEPC). Their
decays provide an excellent place for studying excited nucleons and hyperons --
$N^*$, $\Lambda^*$, $\Sigma^*$ and $\Xi^*$ resonances. The systematic study of
these excited nucleons and hyperons can provide us with critical insights into
the internal quark structure of baryons.


title:
Two-loop Radiative Neutrino Mechanism in an $SU(3)_L\times U(1)_N$ Gauge
  Model

abstract:
  By using the $L_e$ - $L_\mu$ - $L_\tau$ symmetry, we construct an
$SU(3)_L\times U(1)_N$ gauge model that provides two-loop radiative neutrino
masses as well as one-loop radiative neutrino masses. The generic smallness of
two-loop neutrino masses leading to $\Delta m^2_\odot$ compared with one-loop
neutrino masses leading to $\Delta m^2_{atm}$ successfully explains $\Delta
m^2_{atm}$ $>>$ $\Delta m^2_{\odot}$ by invoking the $L_e$ - $L_\mu$ - $L_\tau$
breaking. The Higgs scalar ($h^+$) that initiates radiative mechanisms is
unified into a Higgs triplet together with the standard Higgs scalar ($\phi^+$,
$\phi^0$) to form ($\phi^+$, $\phi^0$, $h^+$), which calls for three families
of lepton triplets: ($\nu^i_L$, $\ell^i_L$, $\omega^i_L$) (i = 1,2,3), where
$\omega^i$ denote heavy neutral leptons. The two-loop radiative mechanism is
found possible by introducing a singly charged scalar, which couples to
$\ell^i_R\omega^j_R$ (i,j = 2,3).


title: Experimental Probes of Localized Gravity: On and Off the Wall

abstract:
  The phenomenology of the Randall-Sundrum model of localized gravity is
analyzed in detail for the two scenarios where the Standard Model (SM) gauge
and matter fields are either confined to a TeV scale 3-brane or may propagate
in a slice of five dimensional anti-deSitter space. In the latter instance, we
derive the interactions of the graviton, gauge, and fermion Kaluza-Klein (KK)
states. The resulting phenomenological signatures are shown to be highly
dependent on the value of the 5-dimensional fermion mass and differ
substantially from the case where the SM fields lie on the TeV-brane. In both
scenarios, we examine the collider signatures for direct production of the
graviton and gauge KK towers as well as their induced contributions to
precision electroweak observables. These direct and indirect signatures are
found to play a complementary role in the exploration of the model parameter
space. In the case where the SM field content resides on the TeV-brane, we show
that the LHC can probe the full parameter space and hence will either discover
or exclude this model if the scale of electroweak physics on the 3-brane is
less than 10 TeV. We also show that spontaneous electroweak symmetry breaking
of the SM must take place on the TeV-brane.


title: Large Extra Dimensions in Rare Decays

abstract:
  The prospect of experimental verification of the large extra dimension
scenario in rare decays is discussed. The case of J/\Psi and \Upsilon to photon
+ missing energy is calculated in detail, and it is shown that the limit on the
compactification scale M_S lies at present in the ten GeV range. In contrast to
the quarkonium systems, signals in Kaon and Pion decays will be small.


title:
Improved Unitarized Heavy Baryon Chiral Perturbation Theory for $\pi N $
  Scattering

abstract:
  We show how the unitarized description of pion nucleon scattering within
Heavy Baryon Chiral Perturbation Theory can be considerably improved, by a
suitable reordering of the expansion over the nucleon mass. Within this
framework, the $\Delta$ resonance and its associated pole can be recovered from
the chiral parameters obtained from low-energy determinations. In addition, we
can obtain a good description of the six $S$ and $P$ wave phase shifts in terms
of chiral parameters with a natural size and compatible with the Resonance
Saturation Hypothesis.


title: Helicity in diffractive vector-meson production

abstract:
  We study the helicity amplitudes describing the quasielastic production of
vector mesons in deep inelastic scattering within the context of the model
which we previously introduced to describe the ratio of longitudinal to
transverse cross sections. We calculate here a full set of spin flip (and
non-flip) amplitudes and naturally find a significant violation of s-channel
helicity conservation. We present predictions for the 15 spin-density matrix
elements which completely define the angular distributions and the helicity
properties of the produced meson.


title: S-wave Kpi scattering in chiral perturbation theory with resonances

abstract:
  We present a detailed analysis of S-wave Kpi scattering up to 2 GeV, making
use of the resonance chiral Lagrangian predictions together with a suitable
unitarisation method. Our approach incorporates known theoretical constraints
at low and high energies. The present experimental status, with partly
conflicting data from different experiments, is discussed. Our analysis allows
to resolve some experimental ambiguities, but better data are needed in order
to determine the cross-section in the higher-energy range. Our best fits are
used to determine the masses and widths of the relevant scalar resonances in
this energy region.


title: Verifiable Model of Neutrino Masses from Large Extra Dimensions

abstract:
  We propose a new scenario of neutrino masses with a Higgs triplet
$(\xi^{++},\xi^+,\xi^0)$ in a theory of large extra dimensions. Lepton number
violation in a distant brane acts as the source of a very small trilinear
coupling of $\xi$ to the standard Higgs doublet in our brane. Small realistic
Majorana neutrino masses are \underline{naturally} obtained with the
fundamental scale $M_* \sim {\cal O}(1)$ TeV, foretelling the possible
discovery of $\xi$ $(m_\xi\lsim M_*)$ at future colliders. Decays of $\xi^{++}$
into same-sign dileptons are fixed by the neutrino mass matrix. Observation of
$\mu-e$ conversion in nuclei is predicted.


title:
The GUT Scale and Superpartner Masses from Anomaly Mediated
  Supersymmetry Breaking

abstract:
  We consider models of anomaly-mediated supersymmetry breaking (AMSB) in which
the grand unification (GUT) scale is determined by the vacuum expectation value
of a chiral superfield. If the anomaly-mediated contributions to the potential
are balanced by gravitational-strength interactions, we find a
model-independent prediction for the GUT scale of order $M_{\rm Planck} /
(16\pi^2)$. The GUT threshold also affects superpartner masses, and can easily
give rise to realistic predictions if the GUT gauge group is asymptotically
free. We give an explicit example of a model with these features, in which the
doublet-triplet splitting problem is solved. The resulting superpartner
spectrum is very different from that of previously considered AMSB models, with
gaugino masses typically unifying at the GUT scale.


title: Squeezed Fermions at Relativistic Heavy Ion Colliders

abstract:
  Large back-to-back correlations of observable fermion -- anti-fermion pairs
are predicted to appear, if the mass of the fermions is modified in a
thermalized medium. The back-to-back correlations of protons and anti-protons
are experimentally observable in ultra-relativistic heavy ion collisions,
similarly to the Andreev reflection of electrons off the boundary of a
superconductor. While quantum statistics suppresses the probability of
observing pairs of fermions with nearby momenta, the fermionic back-to-back
correlations are positive and of similar strength to bosonic back-to-back
correlations.


title:
Constraining Anomaly Mediated Supersymmetry Breaking Framework via
  Ongoing Muon g-2 Experiment at Brookhaven

abstract:
  The ongoing high precision E821 Brookhaven National Laboratory experiment on
muon g-2 is promising to probe a theory involving supersymmetry. We have
studied the constraints on the minimal Anomaly Mediated Supersymmetry Breaking
(AMSB) model using the current data of muon g-2 from Brookhaven. A scenario of
seeing no deviation from the Standard Model is also considered, within a
$2\sigma$ limit of the combined error from the Standard Model result and the
Brookhaven predicted uncertainty level. The resulting constraint is found to be
complementary to what one obtains from $b \to s+ \gamma$ bounds within the AMSB
scenario, since only a definite sign of $\mu$ is effectively probed via $b \to
s+ \gamma$. A few relevant generic features of the model are also described for
disallowed regions of parameter space.


title: A Topcolor Jungle Gym

abstract:
  We discuss an alternative to the topcolor seesaw mechanism. In our scheme,
all the light quarks carry topcolor, and there are many composite SU(2)
doublets. This makes it possible to get the observed top quark mass and
observed $SU(2) \times U(1)$ breaking in a way that is quite different from the
classic seesaw mechanism. We discuss a model of this kind that arises naturally
in the context of dynamically broken topcolor. There are many composite scalars
in a theory of this kind. This has important effects on the Pagels-Stokar
relation and the Higgs mass. We find $m_{\rm Higgs} < 330$ GeV, lighter than in
typical topcolor models. We also show that the electroweak singlet quarks in
such a model can be lighter than the corresponding quarks in a seesaw model.


title: Chiral Models of Weak Scale Supersymmetry

abstract:
  I discuss supersymmetric extensions of the Standard Model containing an extra
U(1)' gauge symmetry which provide a solution to the mu-problem and at the same
time protect the proton from decaying via dimension 4 operators. Moreover, all
fields are protected by chirality and supersymmetry from acquiring high scale
masses. The additional requirements of anomaly cancellation and gauge coupling
unification imply the existence of extra matter multiplets and that several
fields participate in U(1)' symmetry breaking simultaneously. While there are
several studies addressing subsets of these requirements, this work uncovers
simultaneous solutions to all of them. It is surprising and encouraging that
extending the Minimal Supersymmetric Standard Model by a simple U(1) factor
solves its major drawbacks with respect to the non-supersymmetric Standard
Model, especially as current precision data seem to offer a hint to the
existence of its corresponding Z' boson. It is also remarkable that there are
many solutions where the U(1)' charges of the known quarks and leptons are
predicted to be identical to those E_6 motivated Z' bosons which give the best
fit to the data. I discuss the solutions to these constraints including some
phenomenological implications.


title: Asymptotic Behavior of Perturbations in Randall-Sundrum Brane-World

abstract:
  The asymptotic behavior of metric perturbations in Randall-Sundrum infinite
brane world is carefully investigated. Perturbations generated by matter fields
on the brane are shown to be regular even at the future Cauchy horizon.


title: Deep-inelastic structure functions: Reconstruction from Mellin moments

abstract:
  We summarize the method of calculating Mellin moments of deep-inelastic
structure functions in perturbative QCD. We briefly discuss all steps to a
complete analytical reconstruction of the perturbative corrrections in x-space.


title:
A Possible Arena for Searching New Physics - the $\Gamma(D^0 \to \rho^0
  \gamma)/\Gamma (D^0 \to \omega \gamma)$ Ratio

abstract:
  We propose to investigate flavour changing neutral currents in the $c \to u
\gamma$ transition through the measurement of the difference between $\Gamma
(D^0 \to \rho^0 \gamma)$ and $\Gamma (D^0 \to \omega \gamma)$. This is based on
the observation that $D^0 \to (d \bar d) \gamma$ is due to long distance
physics while $D^0 \to (u \bar u) \gamma$ arises from the $c \to u \gamma$
transition. The effect of $\rho - \omega$ mixing is included. A difference in
the decay widths of more than about 30% would be indicative of new physics.


title: Predictions for Lepton Flavour Violation in Z decays

abstract:
  Recent experimental results suggest that the neutrinos of the Standard Model
are massive, though light. Therefore they may mix with each other giving rise
to lepton flavour or even lepton number violating processes, depending on
whether they are Dirac or Majorana particles. Furthermore, the lightness of the
observed neutrinos may be explained by the existence of heavy ones, whose
effects on LFV would be very sizeable. We present an analysis of the effect of
massive neutrinos on flavour-changing decays of the Z boson into leptons, at
the one-loop level, independent of neutrino mass models. Constraints from
present experiments are taken into account.


title: Theoretical status of epsilon'/epsilon

abstract:
  We review the theory of epsilon'/epsilon and present an updated
phenomenological analysis using hadronic matrix elements from lattice QCD. The
present status of the computation of epsilon'/epsilon, considering various
approaches to the matrix-element evaluation, is critically discussed.


title:
Induced theta-vacuum states in heavy ion collisions: a possible
  signature

abstract:
  It has been suggested recently that an arbitrary induced theta-vacuum state
could be created in heavy ion collisions. If such a state can be created, it
would decay by various mechanisms to the fundamental theta=0 state which is the
true ground state of our world. In the following we will discuss the
possibility of studying this unusual state through the emission of pions,
eta-mesons, and eta'-mesons. We will also present the spectrum of the produced
particles in this non-zero theta background. We use the instantaneous
perturbation theory for our estimates.


title: Symmetries and Symmetry Breaking

abstract:
  Several new proton-proton parity violation experiments are presently either
being performed or are being prepared for execution in the near future.
Similarly, a new measurement of the parity-violating gamma-ray asymmetry in
polarized neutron capture on the proton is being developed with a ten-fold
improvement over previous measurements. These experiments are intended to
provide stringent constraints on the set of seven effective weak meson-nucleon
coupling constants. Time-reversal-invariance non-conservation has now been
unequivocally demonstrated in a direct measurement at CPLEAR. Tests may also be
made of time-reversal-invariance non-conservation in systems other than the
kaon system. There exist two classes of time-reversal invariance breaking
interactions: P-odd/T-odd and P-even/T-odd interactions. Constraints on the
first ones stem from measurements of the electric dipole moment of the neutron,
while constraints on the second ones stem from the same and measurements of
charge symmetry breaking in neutron-proton elastic scattering and from $K$
semi-leptonic decays. A series of precision experiments, either ongoing or
being prepared, will determine the neutral weak current of the proton by
measuring the parity-violating normalized asymmetry in electron-proton elastic
scattering. A direct comparison between the electromagnetic and neutral weak
ground state currents of the nucleon will allow a delineation of the
contributions to these currents of the various quark flavours, including quarks
which belong exclusively to the nucleon sea. An extension of these precision
experiments to very low momentum transfer would permit stringent limits to be
placed on physics beyond the standard model.


title: Anomaly Matching in Gauge Theories at Finite Matter Density

abstract:
  We investigate the application of 't Hooft's anomaly matching conditions to
gauge theories at finite matter density. We show that the matching conditions
constrain the low-energy quasiparticle spectrum associated with possible
realizations of global symmetries.


title: Effects of The Initial Hadron in $B\to J/\psi+X$

abstract:
  In the framework of HQET inclusive decays of b-flavored hadrons can be
handled as decays of the free b-quark approximately. We analyse the correction
to this approximation for the inclusive decays into a polarized $J/\psi$,the
correction is characterized by two matrix elements defined in HQET. For the
$J/\psi$ we use NRQCD to parameterize the formation of the $c\bar c$ pair into
$J/\psi$. Numerically the correction is remarkably large, it can be at the
level of 30% and it is mainly due to the Fermi-motion of the $b$-quark. With
this correction we give a new determination for combinations of two NRQCD
matrix elements.


title:
Electromagnetic Pion and Nucleon Form Factors at Positive and Negative
  $q^2$ Within the Framework of Quark-Gluon Strings Model

abstract:
  The electromagnetic form factors of pion and nucleon are considered within
the framework of the Quark-Gluon Strings Model, where the dependence of the
form factors on $q^2$ is determined by the intercept of a dominant Regge
trajectory and Sudakov form factor. The analytical expressions for the form
factors found in the time-like region can be directly continued to the
space-like region. Good agreement with available experimental data on the pion
and magnetic nucleon form factor is obtained at positive as well as negative
$q^2$. It is shown that the difference in $F_\pi$ and $G_m$ at positive and
negative values of $q^2$ is mainly related to the behavior of the double
logarithmic term in the exponent of Sudakov form factor. The model describes
also existing data on the Pauli nucleon form factor $F_2$ and the ratio
$G_e/G_m$.


title: A new approach to multi-jet calculations in hadron collisions

abstract:
  The ALPHA algorithm to evaluate the exact, tree-level matrix elements is
reviewed in the context of multi-parton processes in QCD. The algorithm is
suited for the authomatic calculation of tree-level scattering amplitudes and
allows for straightforward inclusion of mass effects. It's CPU cost grows like
K^n (K constant, n number of external particles) as opposed to the factorial
growth of Feynman graphs. I also discuss the summation over colour
configurations which is designed to allow the construction of parton-level
event generators suitable to interfacing with a parton-shower evolution
including the effects of colour-coherence. Explicit results for the total rates
and differential distributions of processes with 8 final-state partons are
given.


title:
Structure of the Yang-Mills vacuum in the zero modes enhancement quantum
  model

abstract:
  We have formulated new quantum model of the QCD vacuum using the effective
potential approach for composite operators. It is based on the existence and
importance of such kind of the nonperturbative, topologically nontrivial
excitations of gluon field configurations, which can be effectively correctly
described by the $q^{-4}$-type behavior of the full gluon propagator in the
deep infrared domain. The ultraviolet part of the full gluon propagator was
approximated by the asymptotic freedom to-leading order perturbative logarithm
term of the running coupling constant. Despite the vacuum energy density
remains badly divergent, we have formulated a method how to establish a finite
(in the ultraviolet limit) relation between the two scale parameters of our
model. We have expressed the asymptotic scale parameter as $pure number$ times
the nonperturbative scale, which is inevitably contained in any realistic
Ansatz for the full gluon propagator.


title: One-loop fermion determinant with explicit chiral symmetry breaking

abstract:
  We use a proper-time regularization to define the one-loop fermion
determinant for the case in which explicit chiral symmetry breaking takes
place. We show how to obtain the polynomial by which the standard definition of
lndetD needs to be modified in order to arrive at the fermion determinant whose
transformation properties are consistent with the general symmetry requirements
of the basic Lagrangian. As an example it is shown how the fundamental
symmetries and the explicit chiral symmetry breaking pattern associated with
the ENJL model are preserved in a consistent way.


title: Towards a unified theory of gauge and Yukawa interactions

abstract:
  It is suggested to combine gauge and Yukawa interactions into one expression
involving the generalized Dirac operator associated with a superconnection
$D+L$, $L$ being linked to the Higgs field (one doublet). We advocate a version
of the Minimal Standard Model where the Higgs field gives masses to the
neutrinos and a CKM matrix to the leptons.


title: Gell-Mann - Low Function in the Phi^4 Theory

abstract:
  An algorithm is proposed for the determination of the asymptotics of a sum of
a perturbation series from the given values of its coefficients in the
strong-coupling limit. When applied to the \Phi^4 theory, the algorithm yields
the \beta(g)\propto g^\alpha behavior with \alpha\approx 1 at large g for the
Gell-Mann - Low function.


title:
Back reaction of a long range force on a Friedmann-Robertson-Walker
  background

abstract:
  It is possible that there may exist long-range forces in addition to gravity.
In this paper we construct a simple model for such a force based on exchange of
a massless scalar field and analyze its effect on the evolution of a
homogeneous Friedmann-Robertson-Walker cosmology. The presence of such an
interaction leads to an equation of state characterized by positive pressure
and to resonant particle production similar to that observed in preheating
scenarios.


title:
On the Inclusive Determination of V_{ub} from the Lepton Invariant Mass
  Spectrum

abstract:
  Bauer, Ligeti and Luke have recently proposed a new method for measuring
|V_{ub}| in inclusive semileptonic B decays, using a cut on the lepton
invariant mass to discriminate against b->c transitions. We investigate the
structure of the heavy-quark expansion for this case and show that to all
orders the magnitude of the leading perturbative and nonperturbative
corrections is controlled by a hadronic scale mu_c=O(m_c) depending on the
minimal value of q^2. These corrections can be analyzed using a modified
version of the heavy-quark expansion (``hybrid expansion''). We find that the
theoretical uncertainty in the extraction of |V_{ub}| is a factor 2.5 larger
than previously estimated, which allows for a determination with 10% accuracy.


title: Effective String Theory of Vortices and Regge Trajectories

abstract:
  Starting from a field theory containing classical vortex solutions, we obtain
an effective string theory of these vortices as a path integral over the two
transverse degrees of freedom of the string. We carry out a semiclassical
expansion of this effective theory, and use it to obtain corrections to Regge
trajectories due to string fluctuations.


title: Strong decays and Adler selfconsistency condition in two-dimensional QCD

abstract:
  Strong mesonic decays are studied in the framework of the 't Hooft model for
the two-dimensional QCD in the axial gauge. Special attention is payed to the
processes with pions in the final state involved and the low energy theorems
have been checked including the "Adler zero". It is demonstrated explicitly
that in the chiral limit any three-meson decay amplitude with at least one pion
vertex vanishes identically for any values of the external momenta. Ward
identities for the dressed vector and axial-vector currents vertices are
identified and their relationship to the pionic vertex are discussed.


title: Inhomogeneous nucleation in quark hadron phase transition

abstract:
  The effect of subcritical hadron bubbles on a first-order quark-hadron phase
transition is studied. These subcritical hadron bubbles are created due to
thermal fluctuations, and can introduce a finite amount of phase mixing (quark
phase mixed with hadron phase) even at and above the critical temperature. For
reasonable choices of surface tension and correlation length, as obtained from
the lattice QCD calculations, we show that the amount of phase mixing at the
critical temperature remains below the percolation threshold. Thus, as the
system cools below the critical temperature, the transition proceeds through
the nucleation of critical-size hadron bubbles from a metastable quark-gluon
phase (QGP), within an inhomogeneous background populated by an equilibrium
distribution of subcritical hadron bubbles. The inhomogeneity of the medium
results in a substantial reduction of the nucleation barrier for critical
bubbles. Using the corrected nucleation barrier, we estimate the amount of
supercooling for different parameters controlling the phase transition, and
briefly discuss its implications to cosmology and heavy-ion collisions.


title: QCD sum rules as applied to heavy baryons

abstract:
  We give an overview over recent calculations of baryonic correlator functions
with finite mass quarks in view on their applicability for QCD sum rules. The
QCD sum rule method is then demonstrated within the Heavy Quark Effective
Theory.


title: Vibrating the QCD string

abstract:
  The large distance behaviour of the adiabatic hybrid potentials is studied in
the framework of the QCD string model. The calculated spectra are shown to be
the result of interplay between potential-type longitudinal and string-type
transverse vibrations.


title: Structure of High Order Corrections to Lipatov's Asymptotics

abstract:
  High orders of perturbation theory can be calculated by the Lipatov method,
whereby they are determined by saddle-point configurations (instantons) of the
corresponding functional integrals. For most field theories, the Lipatov
asymptotics has the functional form c a^N \Gamma(N+b) (N is the order of
perturbation theory), and the relative corrections to it have a form of a
series in powers of 1/N. It is shown that this series diverges factorially and
its high-order coefficients can be calculated using a procedure similar to
Lipatov's one. The K-th expansion coefficient has the form
const(\ln(S1/S0))^{-K}\Gamma(K+(r1-r0)/2), where S0 and S1 are the values of
the action for the first and the second instanton of the field theory under
consideration, while r0 and r1 are the corresponding numbers of zero modes. The
instantons satisfy the same equation as in the Lipatov method and are assumed
to be renumbered in order of increasing of their action. This result has the
universal character and is valid in any field theory for which the Lipatov
asymptotic form is as specified above.


title: The Semiclassical Approach to Small x Physics

abstract:
  The semiclassical approach to small-x physics is briefly reviewed, where the
main emphasis is on the determination of the gluon distribution at NLO.


title: A Predictive Minimal Model for Neutrino Masses and Mixings

abstract:
  A model is considered in which the scale of the heavy singlet neutrinos is a
few orders of magnitude below the grand unification scale and where
right-handed vector bosons play still a negligible role. In a basis with
diagonal up-quark and Dirac-neutrino mass matrices it is assumed that the heavy
neutrino mass matrix has only zero elements in its diagonal, in analogy to the
light neutrino mass matrix in the Zee model. Connecting then the remaining
matrix elements with the small parameter describing the hierarchy of quark
masses and mixings and by assuming commutativity of the charged lepton with the
down-quark mass matrix, the calculation of all neutrino properties can be
performed in terms of the two mass differences relevant for atmospheric and
solar neutrino oscillations. CP-violation is directly related to CP-violation
in the quark sector.


title: Mass gap effects and higher order electroweak Sudakov logarithms

abstract:
  The infrared structure of spontaneously broken gauge theories is
phenomenologically very important and theoretically a challenging problem.
Various attempts have been made to calculate the higher order behavior of large
double-logarithmic (DL) corrections originating from the exchange of
electroweak gauge bosons resulting in contradictory claims. We present results
from two loop electroweak corrections for the process $g \longrightarrow f_{\rm
R} {\bar f}_{\rm L}$ to DL accuracy. This process is ideally suited as a
theoretical model reaction to study the effect of the mass gap of the neutral
electroweak gauge bosons at the two loop level. Contrary to recent claims in
the literature, we find that the calculation performed with the physical
Standard Model fields is in perfect agreement with the results from the
infrared evolution equation method. In particular, we can confirm the
exponentiation of the electroweak Sudakov logarithms through two loops.


title: Correlations of Solar Neutrino Observables for SNO

abstract:
  Neutrino oscillation scenarios predict correlations, and zones of avoidance,
among measurable quantities such as spectral energy distortions, total fluxes,
time dependences, and flavor content. The comparison of observed and predicted
correlations will enhance the diagnostic power of solar neutrino experiments. A
general test of all presently-allowed (two neutrino) oscillation solutions is
that future measurements must yield values outside the predicted zones of
avoidance. To illustrate the discriminatory power of the simultaneous analysis
of multiple observables, we map currently allowed regions of neutrino masses
and mixing angles onto planes of quantities measurable with the Sudbury
Neutrino Observatory (SNO). We calculate the correlations that are predicted by
vacuum and MSW (active and sterile) neutrino oscillation solutions that are
globally consistent with all available neutrino data. We derive approximate
analytic expressions for the dependence of individual observables and specific
correlations upon neutrino oscillations parameters. We also discuss the
prospects for identifying the correct oscillation solution using multiple SNO
observables.


title:
Radiative tail from the quasielastic peak in deep inelastic scattering
  of polarized leptons off polarized He-3

abstract:
  The contribution of the radiative tail from the quasielastic peak to low
order radiative correction to deep inelastic scattering of polarized leptons by
polarized $^3$He was calculated within the sum rules formalism and $y$-scaling
hypothesis. Numerical analysis was carried out under the conditions of HERMES
experiment.


title: DIS structure functions from the saturation model

abstract:
  We present a description of inclusive and diffractive structure functions in
DIS at small $x$, using a model based on high energy factorization. In this
model the two processes have physical interpretation in terms of the virtual
photon wave function and the dipole cross section. We postulate the dipole
cross section form in a way in which unitarity is taken into account. A good
description of data (including DIS diffraction) is obtained after determining
three parameters of the dipole cross section from the fit to inclusive data
only.


title:
Exclusive Hadronic D Decays to $\eta'$ or $\eta$: Addendum on Resonant
  Final-State Interactions

abstract:
  For hadronic two-body decays of charmed mesons involving $\eta$ or $\eta'$,
resonance-induced final-state interactions (FSI) that mimic the W-exchange or
the W-annihilation topology can play an essential role. In particular, the
decays $D^0\to\bar K^0\eta'$ and $D^+\to\pi^+\eta$, which are largely
suppressed in the absence of FSI, are enhanced dramatically by resonant FSI. It
is stressed that the effect of resonant FSI is negligible for
$\rho^+(\eta,\eta')$ final states because of the mismatch of the G parity of
$\rho^+(\eta,\eta')$ and the J=0, I=1 meson resonance. We argue that a possible
gluon-mediated process in which two gluons couple directly to the gluonic
component of the $\eta'$, e.g. the gluonium, rather than to the flavor-singlet
$\eta_0$, can enhance both modes $D_s^+\to\rho^+\eta'$ and
$D_s^+\to\rho^+\eta$, especially the former; that is, this new mechanism can
account for the unexpectedly large branching ratio of $\rho^+\eta'$ without
suppressing $\rho^+\eta$.


title: Photon structure at HERA

abstract:
  The structure of the virtual photon and its contribution to small x processes
in deep inelastic scattering at HERA is discussed.


title: The light sigma meson

abstract:
  In the framework of the dispersion relation N/D-approach, we restore the
low-energy pi-pi (IJ^{PC}=00^{++})-wave amplitude sewing it with the previously
obtained K-matrix solution for the region 450-1900 MeV. The restored
N/D-amplitude has a pole on the second sheet of the complex-s plane near the
pi-pi threshold, that is the light sigma meson.


title: Democratic Universal Seesaw Model with Three Light Sterile Neutrinos

abstract:
  Based on the "democratic" universal seesaw model, where mass matrices $M_f$
of quarks and leptons f_i (f=u,d,\nu,e; i=1,2,3) are given by a seesaw form
M_f\simeq -m_L M_F^{-1} m_R, and m_L and m_R are universal for all the fermion
sectors, and the mass matrices M_F of hypothetical heavy fermions F_i have a
democratic structure, a possible neutrino mass matrix is investigated. In the
model, there are three sterile neutrinos \nu_{iR} which mix with the active
neutrinos \nu_{iL} with \theta \sim 10^{-2} and which are harmless for
constraint from the bib bang nucleosynthesis. The atmospheric, solar and LSND
neutrino data are explained by the mixings \nu_{\mu L} \leftrightarrow\nu_{\tau
L}, \nu_{eL}\leftrightarrow \nu_{eR} and \nu_{eL}\leftrightarrow \nu_{\mu L},
respectively. The model predicts that \Delta m^2_{solar}/\Delta m^2_{atm}
\simeq (R^2-1) m_e/\sqrt{m_\mu m_\tau} [R=m(\nu_{iR})/m(\nu_{iL}) (i=1,2,3)]
with \sin^{2}2\theta_{atm}\simeq 1 and \Delta m_{LSND}^2/\Delta m^2_{atm}
\simeq (1/4)\sqrt{m_\mu/m_e} with \sin^2 2\theta_{LSND} \simeq 4m_e/m_\mu.


title: Quark-Gluon Plasma Fireball

abstract:
  Lattice-QCD results provide an opportunity to model, and extrapolate to
finite baryon density, the properties of the quark-gluon plasma (QGP). Upon
fixing the scale of the thermal coupling constant and vacuum energy to the
lattice data, the properties of resulting QGP equations of state (EoS) are
developed. We show that the physical properties of the dense matter fireball
formed in heavy ion collision experiments at CERN-SPS are well described by the
QGP-EoS we presented. We also estimate the properties of the fireball formed in
early stages of nuclear collision, and argue that QGP formation must be
expected down to 40A GeV in central Pb--Pb interactions.


title: Superheavy Particles in Friedmann Cosmology and the Dark Matter Problem

abstract:
  The model of creation of observable particles and particles of the dark
matter, considered to be superheavy particles, due to particle creation by the
gravitational field of the Friedmann model of the early Universe is given.
Estimates on the parameters of the model leading to observable values of the
baryon number of the Universe and the dark matter density are made.


title:
Nonlinear sigma model approach for chiral fluctuations and symmetry
  breakdown in Nambu-Jona-Lasinio model

abstract:
  In this paper we discuss symmetry breakdown in NJL model at low N_c. In
particular we propose a modified NJL model that displays a symmetry breakdown
and also at finite temperatures under certain conditions the chiral
fluctuations in this model give rise to a phase analogous to pseudogap phase of
strong-coupling and low carrier density superconductors.


title: Random values of the cosmological constant

abstract:
  One way that an anthropic selection mechanism may be manifest in a physical
theory involves multiple domains in the universe with different values of the
physical parameters. If this mechanism is to be relevant for understanding the
small observed value of the cosmological constant, it may involve a mechanism
by which some contributions to the cosmological constant can be fixed at a
continuous range of values in the different domains. I study the properties of
four possible mechanisms, including the possibility of the Hubble damping of a
scalar field with an extremely flat potential. Another interesting possibility
involves fixed random values of non-dynamical form fields, and a cosmological
mechanism is suggested. This case raises the possibility of anthropic selection
of other parameters in addition. Further requirements needed for a consistent
cosmology are discussed.


title: Improved Conformal Mapping of the Borel Plane

abstract:
  The conformal mapping of the Borel plane can be utilized for the analytic
continuation of the Borel transform to the entire positive real semi-axis and
is thus helpful in the resummation of divergent perturbation series in quantum
field theory. We observe that the rate of convergence can be improved by the
application of Pad\'{e} approximants to the Borel transform expressed as a
function of the conformal variable, i.e. by a combination of the analytic
continuation via conformal mapping and a subsequent numerical approximation by
rational approximants. The method is primarily useful in those cases where the
leading (but not sub-leading) large-order asymptotics of the perturbative
coefficients are known.


title: Masses and Mixings from Neutrino Beams pointing to Neutrino Telescopes

abstract:
  We discuss the potential to determine leading oscillation parameters, the
value and the sign of \Delta m^2_{31}, as well as the magnitude of \sin^2
2\theta_{13} using a conventional wide band neutrino beam pointing to water or
ice Cherenkov neutrino detectors known as ``Neutrino Telescopes''. We find that
precision measurements of \Delta m^2_{31} and \theta_{23} are possible and
that, even though it is not possible to discriminate between charges in the
detector, there is a remarkably good sensitivity to the mixing angle
\theta_{13} and the sign of \Delta m^2_{31}.


title: O(m_d-m_u) Effects in CP-even and CP-odd K-->pi pi Decays

abstract:
  Strong isospin-breaking (IB) effects in CP-even and CP-odd K-->pi pi decays
are computed to next-to-leading order (NLO) in the chiral expansion. The impact
of these corrections on the magnitude of the Delta I=1/2 Rule and on the size
of the IB correction, Omega_IB, to the gluonic penguin contribution to
epsilon'/epsilon are discussed.


title:
Robust flavor equalization of cosmic neutrino flux by quasi bi-maximal
  mixing

abstract:
  For high energy cosmic neutrinos Athar, Jezabek, and Yasuda (AJY) have
recently shown that the existing data on neutrino oscillations suggests that
cosmic neutrino flux at the AGN/GRB source, F(nu_e):F(nu_mu):F(nu_tau) approx
1:2:0, oscillates to F(nu_e):F(nu_mu):F(nu_tau) approx 1:1:1. These results can
be confirmed at AMANDA, Baikal, ANTARES and NESTOR, and other neutrino
detectors with a good flavor resolution. Here, we re-derive the AJY result from
quasi bi-maximal mixing, and show that observation of
F(nu_e):F(nu_\mu):F(nu_tau) approx 1:1:1 does not necessarily establish cosmic
neutrino flux at the AGN/GRB source to be F(nu_e):F(nu_mu):F(nu_tau) approx
1:2:0.


title:
Hierarchical Radiative Quark Mass Matrices with an $U(1)_X$ Horizontal
  Symmetry Model

abstract:
  In a model with a gauge group $G_{SM}\otimes U(1)_X$, where $G_{SM} \equiv
SU(3)_C \otimes SU(2)_L \otimes U(1)_Y$ is the standard model gauge group and
$U(1)_X$ is a horizontal local gauge symmetry, we propose a radiative
generation of the spectrum of quark masses and mixing angles. The assignment of
horizontal charges is such that at tree level only the third family is massive.
Using these tree level masses and introducing exotic scalars, the light
families of quarks acquire hierarchical masses through radiative corrections.
The rank three quark mass matrices obtained are written in terms of a minimal
set of free parameters of the model, whose values are estimated performing a
numerical fit. The resulting quark masses and CKM mixing angles turn out to be
in good agreement with the experimental values.


title:
Leading logarithm calculation of the e^+ e^- -> e^+ \nu_e \bar{u} d
  cross section

abstract:
  We analytically evaluate in the leading logarithm approximation the
differential cross section for e^+ e^- -> e^+ \nu_e \bar{u} d. We compare our
order \alpha^4 \alpha_s^0 leading-log result to the order \alpha^4 \alpha_s^0
exact result obtained from the GRC4F Monte Carlo program. Finally we use the
Gluck, Reya, Schienbien distribution of partons in a virtual photon, which
incorporates both evolution and nonperturbative strong interaction
contributions, to obtain better estimates of the differential cross section.


title:
Tritium Beta Decay, Neutrino Mass Matrices and Interactions Beyond the
  Standard Model

abstract:
  The interference of charge-changing interactions, weaker than the V-A
Standard Model (SM) interaction and having a different Lorentz structure, with
that SM interaction, can, in principle, produce effects near the end point of
the Tritium beta decay spectrum which are of a different character from those
produced by the purely kinematic effect of neutrino mass expected in the
simplest extension of the SM. We show that the existence of more than one mass
eigenstate can lead to interference effects at the end point that are stronger
than those occurring over the entire spectrum. We discuss these effects both
for the special case of Dirac neutrinos and the more general case of Majorana
neutrinos and show that, for the present precision of the experiments, one
formula should suffice to express the interference effects in all cases.
Implications for "sterile" neutrinos are noted.


title:
The renormalization group for correlated scales: one-stage versus
  two-stage running

abstract:
  Nonrelativistic bound states have two low energy scales, a soft scale mu_S of
order mv and an ultrasoft scale mu_U of order mv^2. In two-stage running, the
soft and ultrasoft scales are lowered from m to mv, and then the ultrasoft
scale is lowered from mv to mv^2. In one-stage running, the two scales are
lowered in a correlated way using a subtraction velocity. We compare these two
methods of summing logarithms and show that only the correlated running in
velocity space of the one-stage method correctly reproduces the logarithms in
non-relativistic bound states in QED. The argument for one-stage running is
general, and should apply to any system with correlated scales.


title: The g-2 of the Muon in Localized Gravity Models

abstract:
  The (g-2) of the muon is well known to be an important model building
constraint on theories beyond the Standard Model. In this paper, we examine the
contributions to $(g-2)_\mu$ arising in the Randall-Sundrum model of localized
gravity for the case where the Standard Model gauge fields and fermions are
both in the bulk. Using the current experimental world average measurement for
$(g-2)_\mu$, we find that strong constraints can be placed on the mass of the
lightest gauge Kaluza-Klein excitation for a narrow part of the allowed range
of the assumed universal 5-dimensional fermion mass parameter, $\nu$. However,
employing both perturbativity and fine-tuning constraints we find that we can
further restrict the allowed range of the parameter $\nu$ to only one fourth of
its previous size. The scenario with the SM in the RS bulk is thus tightly
constrained, being viable for only a small region of the parameter space.


title:
Scale- and scheme-independent extension of Pade approximants; Bjorken
  polarized sum rule as an example

abstract:
  A renormalization-scale-invariant generalization of the diagonal Pad\'e
approximants (dPA), developed previously, is extended so that it becomes
renormalization-scheme-invariant as well. We do this explicitly when two terms
beyond the leading order (NNLO, $\sim \alpha_s^3$) are known in the truncated
perturbation series (TPS). At first, the scheme dependence shows up as a
dependence on the first two scheme parameters $c_2$ and $c_3$. Invariance under
the change of the leading parameter $c_2$ is achieved via a variant of the
principle of minimal sensitivity. The subleading parameter $c_3$ is fixed so
that a scale- and scheme-invariant Borel transform of the resummation
approximant gives the correct location of the leading infrared renormalon pole.
The leading higher-twist contribution, or a part of it, is thus believed to be
contained implicitly in the resummation. We applied the approximant to the
Bjorken polarized sum rule (BjPSR) at $Q^2_{\rm ph}=5$ and $3 GeV^2$, for the
most recent data and the data available until 1997, respectively, and obtained
${\alpha}_s^{\bar MS}(M_Z^2)=0.119^{+0.003}_{-0.006}$ and
$0.113^{+0.004}_{-0.019}$, respectively. Very similar results are obtained with
the Grunberg's effective charge method and Stevenson's TPS principle of minimal
sensitivity, if we fix $c_3$-parameter in them by the aforementioned procedure.
The central values for ${\alpha}_s^{\bar MS}(M_Z^2)$ increase to 0.120 (0.114)
when applying dPA's, and 0.125 (0.118) when applying NNLO TPS.


title: Generic Relations of Flavor Mixings between Leptons and Quarks in SU(5)

abstract:
  We have studied implications of the generic lopsided mass matrix of the
charged leptons by taking the SU(5) GUT relation in the nearest-neighbor
interaction (NNI) basis. We have found four interesting relations among the
lepton mixings and the quark ones, which are independent of details of the
model. These relations are discussed by using the experimental data. We have
also discussed the relation between U_{e2} and U_{e3} incuding the contribution
from the neutrino mass matrix. We have presented the probable value U_{e3}=0.05
\sim 0.16, which is independent of the solar neutrino solutions. The CP
violating quantity J_{CP} is also discussed.


title: Anatomy of the Proton Structure Functions in $\kappa$-factorization

abstract:
  We present the first experiment-based parameterization of differential gluon
structure function, which is called upon in many applications. We compare
$\kappa$-factorization and DGLAP approaches and analyze properties of DGSF,
with special emphasis on soft-to-hard/hard-to-soft diffusion.


title:
Diffractive Vector Meson Production In A Unified $\kappa$-Factorization
  Approach

abstract:
  In the framework of the $\kappa$-factorization approach and on the basis of
recently determined DGSF, we calculated the production rates of ground and
excited (2S and D wave) states of vector mesons and investigated their various
kinematical and spin dependencies. We also addressed the issue of S/D wave
mixing in quarkonia.


title: Light vector meson photoproduction at high $|t|$

abstract:
  We have studied in perturbative QCD all independent helicity amplitudes
describing the photoproduction of light vector mesons at large $t$. We found a
new hard production mechanism which is related to the possibility for a real
photon to fluctuate into a massless $q\bar q$ pair in a chiral-odd spin
configuration. Each helicity amplitude is given as a sum of chiral-even
contribution (when the helicities of quark and antiquark are antiparallel) and
this additional chiral-odd part (where the helicities of quark and antiquark
are parallel). The chiral-odd contribution is large, it leads to a dominance of
the non spin-flip amplitude in a very broad region of intermediately high
$|t|$.}


title: Restrictions on neutrino oscillations from BBN. Non-resonant case

abstract:
  New nucleosynthesis bounds on the oscillation parameters of active neutrinos
mixed with a sterile one are derived for the non-resonant case. The controversy
in the literature whether to use the annihilation rate or the total reaction
rate for the estimates of sterile neutrino production is resolved in favor of
the annihilation rate. In contrast to previous papers, the restrictions on
oscillations of electronic neutrinos are weaker than those of muonic and
tauonic ones.


title: Decays and Lifetime of B_c in QCD Sum Rules

abstract:
  In the framework of three-point QCD sum rules, the form factors for the
semileptonic decays of B_c^+ -> B_s(B_s^*) l \nu are calculated with account
for the Coulomb-like alpha_s/v-corrections in the heavy quarkonium. The
generalized relations due to the spin symmetry of HQET/NRQCD for the form
factors are derived at the recoil momentum close to zero. The nonleptonic
decays are studied using the assumption on the factorization. The B_c meson
lifetime is estimated by summing up the dominating exclusive modes in the c ->
s transition combining the current calculations with the previous analysis of b
-> c decays in the sum rules of QCD and NRQCD.


title: Radiative mass in QCD at high density

abstract:
  We show that radiatively generated Majorana mass for antiquarks is same as
the Cooper-pair gap. We then calculate the electromagnetic corrections to mass
of particles in the color-flavor locking phase of QCD at high density. The mass
spectrum forms multiplets under $SU(2)_V\times U(1)_V$. The charged pions and
kaons get the electromagnetic mass which is proportional to the Cooper-pair
gap.


title: Lifetime Effects in Color Superconductivity at Weak Coupling

abstract:
  Present computations of the gap of color superconductivity in weak coupling
assume that the quarks which participate in the condensation process are
infinitely long-lived. However, the quasiparticles in a plasma are
characterized by having a finite lifetime. In this article we take into account
this fact to evaluate its effect in the computation of the color gap. By first
considering the Schwinger-Dyson equations in weak coupling, when one-loop
self-energy corrections are included, a general gap equation is written in
terms of the spectral densities of the quasiparticles. To evaluate lifetime
effects, we then model the spectral density by a Lorentzian function. We argue
that the decay of the quasiparticles limits their efficiency to condense. The
value of the gap at the Fermi surface is then reduced. To leading order, these
lifetime effects can be taken into account by replacing the coupling constant
of the gap equation by a reduced effective one.


title:
Model-independent analysis of the exclusive semileptonic B -> pi^+ pi^-
  l^+ l^- decay

abstract:
  A model-independent analysis for the exclusive, rare B -> pi^+ pi^- l^+ l^-
decay is presented. The dependence of the various physically measurable
asymmetries and CP violating asymmetry on the new Wilson coefficients is
studied in detail. It is observed that different measurable quantiles are very
sensitive to the different new Wilson coefficients, i.e., to the existence of
new physics beyond standard model.


title: Fractal Electromagnetic Showers

abstract:
  We study the self-similar structure of electromagnetic showers and introduce
the notion of the fractal dimension of a shower. Studies underway of showers in
various materials and at various energies are presented, and the range over
which the fractal scaling behaviour is observed is discussed. Applications to
fast shower simulations and identification, particularly in the context of
extensive air showers, are also discussed.


title: Charmless two body hadronic decays of $\Lambda_b$ baryon

abstract:
  Using a theoretical framework based on the next-to-leading order QCD improved
effective Hamiltonian, we have estimated the branching ratios and asymmetry
parameters for the two body charmless nonleptonic decay modes of $\Lambda_b$
baryon i.e. $\Lambda_b \to p (\pi/\rho),~p(K/K^*)$ and $\Lambda (\pi/\rho)$,
within the framework of generalized factorization. The nonfactorizable
contributions are parametrized in terms of the effective number of colors,
$N_c^{eff}$. So in addition to the naive factorization approach ($N_c^{eff}=3
$), here we have taken two more values for $N_c^{eff}$ i.e., $N_c^{eff}=2 $ and
$\infty $. The baryonic form factors at maximum momentum transfer ($ q_m^2 $)
are evaluated using the nonrelativistic quark model and the extrapolation of
the form factors from $q_m^2$ to the required $q^2$ value is done by assuming
the pole dominance. The obtained branching ratios for $\Lambda_b \to p\pi, ~pK$
processes lie within the present experimental upper limit .


title:
Effects of the Fourth Generation on $\Delta M_{B_{d,s}}$ in $B^0-\bar
  B^0$ Mixing

abstract:
  We investigate the mass differences $\Delta M_{B_{d,s}}$ in the mixing
$B^0_{d,s}-\bar B^0_{d,s}$ with a new up-like quark $t^{\prime}$ in the
sequential fourth generation model. We give the basic formulae for $\Delta
M_{B_{d,s}}$ in this model and obtain two kinds of numerical results of $\Delta
M_{B_{s}}$ which is the function of $m_{t^{\prime}}$. We find that one of our
results can satisfy the present experimental low bound of $\Delta M_{B_s}$. We
also get the constraints of the fourth generation CKM factor
$V^{*}_{t^{'}b}V_{t^{'}d}$, which is the function of $t^{'}$, from the
experimental measurements of $\Delta M_{B_d}$. Thus, $\Delta M_{B_{d,s}}$
provide a possible test of the fourth generation and give a signal of the new
physics.


title: On the Nucleon Stability and Sigma_N Term Puzzles

abstract:
  A stable soliton configuration for a nucleon emerges when the nucleon
stability and $\Sigma_N$ term discrepancy problems are studied
semi-quantitatively within a local theory developed recently. The approach
developed here goes beyond the mean field or Hartree-Fock approximation by
taking into account of the non-perturbative wave function renormalization in a
way that is consistent with the chiral Ward-Takahashi identities of QCD. The
stability condition for a nucleon and the recently extracted nucleon $\Sigma_N$
term are used to estimate the radius of the soliton. It is found that 0.67 fm
$\le R \le$ 0.78 fm. A new mechanism for the stability of a nucleon is
proposed. The discrepancy between the nucleon $\Sigma_N$ term extracted from
pion--nucleon scattering data and the one from baryonic spectra is resolved by
assuming the existence of a metastable virtual color superconducting phase for
the strong interaction vacuum. Under such a scenario, the difference between
the energy density of the chiral symmetry breaking phase and the metastable
color superconducting phase is found to be 0.41 GeV/fm$^3$ $\le
\Delta\epsilon\le $ 0.85 GeV/fm$^3$.


title:
Can CPT Symmetry Be Tested With K^0 vs \bar{K}^0--> \pi^+\pi^-\pi^0
  Decays?

abstract:
  We show that the CP-violating effect in K^0 vs \bar K^0-->\pi^+\pi^-\pi^0
decays differs from that in K_{\rm L}-->\pi^+\pi^-, K_{\rm L}-->\pi^0\pi^0 or
the semileptonic K_{\rm L} transitions, if there exists CPT violation in
K^0-\bar{K}^0 mixing. A delicate measurement of this difference in the KTeV
experiment and at the \phi factory will provide a new test of CPT symmetry in
the neutral kaon system.


title: Axial Anomaly Effects in Pion and $Z^0$ Radiative Decays

abstract:
  We discuss a connection between axial anomaly and polarized radiative
processes. By comparison with the corresponding unpolarized cases, we consider
some physical outputs for the $\pi^+$ and $Z^0$ polarized radiative decays. We
analyse in detail the pattern of mass singularity cancellation.


title:
Searching for Narrow Graviton Resonances with the ATLAS Detector at the
  Large Hadron Collider

abstract:
  A spectrum of massive graviton states is present in several recent
theoretical models that include extra space dimensions. In some such models the
graviton states are well separated in mass, and can be detected as resonances
in collider experiments. The ability of the ATLAS detector at the Large Hadron
Collider to identify such states and measure their properties is considered, in
the case that the resonances are narrow compared to the experimental
resolution. The discovery limits for the detection of the decay mode G->e+e-
are derived. The angular distribution of the lepton pair is used to determine
the spin of the intermediate state. In one specific model, the resonance can be
detected up to a graviton resonance mass of 2080 GeV, while the angular
distribution favours a spin-2 hypothesis over a spin-1 hypothesis at 90%
confidence for resonance masses up to 1720 GeV.


title: Electroweak baryogenesis at and after preheating: What's the difference?

abstract:
  Two recent scenarios of preheating-related baryogenesis are compared within
the framework of Abelian Higgs model in (1+1) dimensions. It is shown that they
shift baryon number in opposite directions. Once both scenarios can realize
simultaneously as overlapped stages of the same physical process, even the sign
of net generated asymmetry becomes dependent on initial parameters.


title: R-symmetry, Yukawa textures and anomaly mediated supersymmetry breaking

abstract:
  We explore, in the MSSM context, an extension of the Anomaly Mediated
Supersymmetry Breaking solution for the soft scalar masses that is possible if
the underlying theory has a gauged R-symmetry. The slepton mass problem
characteristic of the scenario is resolved, and a context for the explanation
of the fermion mass hierarchy provided.


title: The Lame equation in parametric resonance after inflation

abstract:
  We show that the most general inflaton potential in Minkowski spacetime for
which the differential equation for the Fourier modes of the matter fields
reduces to Lam\'e's equation is of the form $V(\phi)=
\lambda\phi^4/4+K\phi^2/2+\mu/(2\phi^2)+V_0$. As an application, we study the
preheating phase after inflation for the above potential with K=0 and arbitrary
$\lambda,\mu>0$. For certain values of the coupling constant between the
inflaton and the matter fields, we calculate the instability intervals and the
characteristic exponents in closed form.


title:
Regge Analysis of Diffractive and Leading Baryon Structure Functions
  from DIS

abstract:
  In this paper we present a combined analysis of the H1 data on leading baryon
and diffractive structure functions from DIS, which are handled as two
components of the same semi-inclusive process. The available structure function
data are analyzed in a series of fits in which three main exchanges are taking
into account: pomeron, reggeon and pion. For each of these contributions, Regge
factorization of the correspondent structure function is assumed. By this
procedure, we extract information about the interface between the diffractive,
pomeron-dominated, region and the leading proton spectrum, which is mostly
ruled by secondary exchanges. One of the main results is that the relative
reggeon contribution to the semi-inclusive structure function is much smaller
than the one obtained from a analysis of the diffractive structure function
alone.


title: Supersymmetric Electroweak Baryogenesis

abstract:
  We re-examine the generation of the baryon asymmetry in the minimal
supersymmetric standard model (MSSM) during the electroweak phase transition.
We find that the dominant source for baryogenesis arises from the chargino
sector. The CP-violation comes from the complex phase in the mu parameter,
which provides CP-odd contributions to the particle dispersion relations. This
leads to different accelerations for particles and antiparticles in the wall
region which, combined with diffusion, leads to the separation of Higgsinos and
their antiparticles in the front of the wall. These asymmetries get transported
to produce perturbations in the left-handed chiral quarks, which then drive
sphaleron interactions to create the baryon asymmetry. We present a complete
derivation of the semiclassical WKB formalism, including the chargino
dispersion relations and a self-consistent derivation of the diffusion
equations starting from semiclassical Boltzmann equations for WKB-excitations.
We stress the advantages of treating the transport equations in terms of the
manifestly gauge invariant physical energy and kinetic momentum, rather than in
the gauge variant canonical variables used in previous treatments. We show that
a large enough baryon asymmetry can be created for the phase of the complex mu
parameter as small as ~ 0.001, which is consistent with bounds from the neutron
electric dipole moment.


title: Additional Isospin-Breaking Effects in epsilon'/epsilon

abstract:
  Isospin-breaking effects, in particular those associated with
electroweak-penguin contributions and pi0-eta,eta' mixing, have long been known
to affect the Standard Model prediction of Re(epsilon'/epsilon) in a
significant manner. We have found an heretofore unconsidered isospin-violating
effect of importance; namely, the u-d quark mass difference can spawn |Delta
I|=3/2 components in the matrix elements of the gluonic penguin operators.
Using chiral perturbation theory and the factorization approximation for the
hadronic matrix elements, we find within a specific model for the low-energy
constants that we can readily accommodate an increase in Re(epsilon'/epsilon)
by a factor of two.


title:
One-Loop Factorization of the Nucleon g_2-Structure Function in the
  Non-Singlet Case

abstract:
  We consider the one-loop factorization of the simplest twist-three process:
inclusive deep-inelastic scattering of longitudinally-polarized leptons on a
transversely-polarized nucleon target. By studying the Compton amplitudes for
certain quark and gluon states at one loop, we find the coefficient functions
for the non-singlet twist-three distributions in the factorization formula of
g_2(x_B,Q^2). The result marks the first step towards a next-to-leading order
(NLO) formalism for this transverse-spin-dependent structure function of the
nucleon.


title:
Charged Higgs decays in models with singlet neutrino in large extra
  dimensions

abstract:
  In models with large extra dimensions and TeV scale quantum gravity, small
(Dirac) neutrino masses can be obtained naturally if the right-handed neutrino
propagates in the extra dimensions. In this scenario, with 2 Higgs doublets, we
show that the decay of charged Higgs into {\em left-handed} charged lepton (say
\tau) and right-handed neutrino can be significantly enhanced, with O(1)
branching ratio, due to the large number of Kaluza-Klein states of the
right-handed neutrino. Since \tau's from the standard decay of charged Higgs
are {\em right-handed}, the above novel charged Higgs decay can provide a
distinctive signature of these models at hadron/lepton colliders. Similarly,
top quark decays to b \mu^+ \nu, b \tau^+ \nu through virtual charged Higgs can
be enhanced.


title: Prospects for observations of high-energy cosmic tau neutrinos

abstract:
  We study prospects for the observations of high-energy cosmic tau neutrinos
(E \geq 10^6 GeV) originating from proton acceleration in the cores of active
galactic nuclei. We consider the possibility that vacuum flavor neutrino
oscillations induce a tau to muon neutrino flux ratio greatly exceeding the
rather small value expected from intrinsic production. The criterias and event
rates for under water/ice light Cerenkov neutrino telescopes are given by
considering the possible detection of downgoing high-energy cosmic tau
neutrinos through characteristic double shower events.


title:
QCD factorization for exclusive, non-leptonic B meson decays: General
  arguments and the case of heavy-light final states

abstract:
  We provide a rigorous basis for factorization for a large class of
non-leptonic two-body $B$-meson decays in the heavy-quark limit. The
factorization formula incorporates elements of the naive factorization approach
and the hard-scattering approach, but allows us to compute systematically
radiative (``non-factorizable'') corrections to naive factorization for decays
such as $B\to D\pi$ and $B\to \pi \pi$. We discuss the factorization formula
for a general final state from a general point of view. We then consider
factorization for decays into heavy-light final states (such as $B\to D\pi$) in
more detail, including a proof of the factorization formula at two-loop order.
Explicit results for the leading QCD corrections to factorization are presented
and compared to existing measurements of branching fractions and final-state
interaction phases.


title:
QCD corrections up to order alpha_s^2 to polarized quark production in
  e^+ e^- -annihilation

abstract:
  The revised version contains two additional references i.e. [13], [14] w.r.t.
to the original paper. Furthermore Eq. (33) in [11] at the end of the paragraph
below (3.17) must be Eq. (33) in [10]. Misprints in the list of references are
corrected.


title: Wavelets on nuclear interactions and QCD on jet multiplicities

abstract:
  This talk at Fradkin conference is devoted to brief description of latest
results in two topics I worked on during last years. The multiresolution
analysis and fast wavelet transform became a standard procedure for pattern
recognition and I describe how it has been used for analysis of high energy
nucleus-nucleus interactions. Latest QCD results on multiplicities in quark and
gluon jets are discussed and confronted to experimental data.


title: CP and T violation in long baseline experiments with low energy neutrino

abstract:
  Stimulated by the idea of PRISM, a very high intensity muon ring with rather
low energy, we consider possibilities of observing CP-violation effects in
neutrino oscillation experiments. Destructive sum of matter effect and
CP-violation effect can be avoided with use of initial $\nu_{\rm e}$ beam. We
finally show that the experiment with (a few) $\times$ 100 MeV of neutrino
energy and (a few) $\times$ 100 km of baseline length, which is considered in
this paper, is particularly suitable for a search of CP violation in view of
3-generation nature of CP violation.


title: New type of stable Q balls in the gauge-mediated supersymmetry breaking

abstract:
  We obtain a new type of a stable Q ball in the context of gauge-mediated
supersymmetry breaking in minimal supersymmetric standard model. It is
so-called gravity-mediation type of Q ball, but stable against the decay into
nucleons, since the energy per unit charge is equal to gravitino mass m_{3/2},
which can be smaller than nucleon mass in the gauge-mediation mechanism. We
consider the cosmological consequences in this new Q-ball scenario, and find
that this new type of the Q ball can be considered as the dark matter and the
source for the baryon number of the universe simultaneously.


title: Anisotropic transverse flow and the quark-hadron phase transition

abstract:
  We use (3+1)-dimensional hydrodynamics with exact longitudinal
boost-invariance to study the influence of collision centrality and initial
energy density on the transverse flow pattern and the angular distributions of
particles emitted near midrapidity in ultrarelativistic heavy-ion collisions.
We concentrate on radial flow and the elliptic flow coefficient v2 as functions
of the impact parameter and of the collision energy. We demonstrate that the
finally observed elliptic flow is established earlier in the collision than the
observed radial flow and thus probes the equation of state at higher energy
densities. We point out that a phase transition from hadronic matter to a
color-deconfined quark-gluon plasma leads to non-monotonic behaviour in both
beam energy and impact parameter dependences which, if observed, can be used to
identify such a phase transition. Our calculations span collision energies from
the Brookhaven AGS (Alternating Gradient Synchrotron) to beyond the LHC (Large
Hadron Collider); the QGP phase transition signature is predicted between the
lowest available SPS (CERN Super Proton Synchrotron) and the highest RHIC
(Brookhaven Relativistic Heavy Ion Collider) energies. To optimize the chances
for applicability of hydrodynamics we suggest to study the excitation function
of flow anisotropies in central uranium-uranium collisions in the side-on-side
collision geometry.


title: Talk on fermion masses and mixings

abstract:
  Two topics are covered in this paper. In the first part the relation between
quark mass matrices and observable quantities in gauge theories. In the second
part neutrino masses and mixings in a seesaw framework.


title: Semi-inclusive vector meson production in DIS

abstract:
  We analyze one-particle inclusive DIS in the case when a spin-1 hadron (such
as a vector meson) is observed in the final state. We consider only leading
order contributions in 1/Q, but we include transverse momentum of partons.
Several new fragmentation functions appear in cross sections. One of them can
be measured in connection with the transverse-spin disbtribution function h_1.


title: Theoretical Overview of CP Violation in B-Meson Decay

abstract:
  After a brief look at CP violation in kaon decays, a short overview of CP
violation in the $B$-meson system and of strategies to determine the angles of
the unitarity triangles of the CKM matrix is given. Both general aspects and
some recent developments are discussed, including $B_c^\pm\to D^\pm_s D$ and
$B\to\pi K$ decays, as well as the $B_d\to\pi^+\pi^-$, $B_s\to K^+K^-$ system.


title:
Parton counting: physical and computational complexity of multi-jet
  production at hadron colliders

abstract:
  We present an enumeration of all possible amplitudes that contribute to an
n-jet process in QCD. We estimate the number of amplitudes for large number of
jets and determine the actual number of amplitudes to be calculated, which is
smaller due to relabelling among (massless) quark flavours.


title:
A unique large thermal source of real and virtual photons in the
  reactions Pb(158 AGeV) + Pb, Au

abstract:
  The data of direct single-photon measurements of the WA98 collaboration in
the reaction Pb(158 AGeV) + Pb are analyzed within a thermal model with a
minimum number of parameters adjusted to the dilepton data obtained by the
CERES and NA50 collaborations in the reactions Pb(158 AGeV) + Au, Pb. The
agreement of our model with the WA98 data points to a unique large thermal
source emitting electromagnetic radiation observable in both the real and
virtual photon channels.


title: A Theoretical Prediction of the Bs-Meson Lifetime Difference

abstract:
  We present the results of a quenched lattice calculation of the operator
matrix elements relevant for predicting the Bs width difference. Our main
result is (\Delta\Gamma_Bs/\Gamma_Bs)= (4.7 +/- 1.5 +/- 1.6) 10^(-2), obtained
from the ratio of matrix elements, R(m_b)=<\bar B_s^0|Q_S|B_s^0>/<\bar
B_s^0|Q_L|B_s^0>=-0.93(3)^(+0.00)_(-0.01). R(m_b) was evaluated from the two
relevant B-parameters, B_S^{MSbar}(m_b)=0.86(2)^(+0.02)_(-0.03) and
B_Bs^{MSbar}(m_b) = 0.91(3)^(+0.00)_(-0.06), which we computed in our
simulation.


title:
Phenomenology of non-standard Z couplings in exclusive semileptonic b ->
  s transitions

abstract:
  The rare decays $B\to K^{(*)}\ell^+\ell^-$, $B\to K^{(*)}\nu\bar\nu$ and
$B_s\to\mu^+\mu^-$ are analyzed in a generic scenario where New Physics effects
enter predominantly via $Z$ penguin contributions. We show that this
possibility is well motivated on theoretical grounds, as the $\bar sbZ$ vertex
is particularly susceptible to non-standard dynamics. In addition, such a
framework is also interesting phenomenologically since the $\bar sbZ$ coupling
is rather poorly constrained by present data. The characteristic features of
this scenario for the relevant decay rates and distributions are investigated.
We emphasize that both sign and magnitude of the forward-backward asymmetry of
the decay leptons in $\bar B\to \bar K^*\ell^+\ell^-$, ${\cal A}^{(\bar
B)}_{FB}$, carry sensitive information on New Physics. The observable ${\cal
A}^{(\bar B)}_{FB}+{\cal A}^{(B)}_{FB}$ is proposed as a useful probe of
non-standard CP violation in $\bar sbZ$ couplings.


title:
The Earth Regeneration Effect of Solar Neutrinos: a Numerical Treatment
  with Three Active Neutrino Flavors

abstract:
  We introduce an integrated algorithm for full scale investigation of the
earth regeneration effect of solar neutrinos with all three active neutrinos.
We illustrate that the earth effect on low energy solar neutrinos ($E_\nu < 20$
MeV) causes large variations in the survival probabilities for large values of
the mixing angle $\theta_{12}$ for a given value of $\theta_{13}$. But it is
maximal for small values of $\theta_{13}$ and diminishes for large values at a
given value of $\theta_{12}$. The nadir angle dependence is sensitive to the
value of $E'\equiv E/\Delta_{12}$. As far as low energy solar neutrinos are
concerned we notice that the earth effect is more pronounced for core
penetration. We confirm that the earth effect leaves the SMA region almost
intact regardless of $\theta_{13}$ and that it is significant for high energy
$^8$B and $hep$ neutrinos in the LMA region. We also show that for large values
of $\theta_{13}$, the earth effect is significant for high energy neutrinos
($E'\gtrsim 10^9$) and it can be large at any nadir angle.


title: U(1) symmetry and R parity violation

abstract:
  The patterns of $R$ violation resulting from imposition of a gauged U(1)
horizontal symmetry on the minimal supersymmetric standard model are
systematically analyzed. We concentrate on class of models with integer U(1)
charges chosen to reproduce the quark masses and mixings as well as charged
lepton masses exactly or approximately. The U(1) charges are further restricted
by the requirement that very large bilinear lepton number violating terms
should not be allowed in the superpotential. It is shown that this leads to
severely constrained patterns of trilinear interactions. Specifically, only
choice compatible with phenomenological restrictions is the one in which all
the trilinear $\lambda'_{ijk}$ and all but at most two trilinear
$\lambda_{ijk}$ couplings vanish or are enormously suppressed. The U(1)
symmetry can allow effective generation of bilinear lepton number violating
parameters through terms in the Kahler potential. Resulting models are
identified and structure of neutrino masses in some of these is briefly
discussed.


title: Nonexistence of the Longitudinal Polarisation of a Massive Gauge Bosons

abstract: This paper has been withdrawn by the authors due to some errors.


title: Neutrino Masses and Leptogenesis

abstract:
  I discuss the connection between neutrino masses and leptogenesis. I use
three prime examples: (1) canonical seesaw, (2) triplet Higgs, and (3) $R$
parity violation.


title: Pomeron models and exchange degeneracy of the Regge trajectories

abstract:
  Two models for the Pomeron, supplemented by exchange degenerate sub-leading
Regge trajectories, are fitted to the forward scattering data for a number of
reactions. By considering new Pomeron models, we extend the recent results of
the COMPAS group, being consistent with our predecessors.


title: NLO Exclusive Evolution Kernels

abstract:
  We outline a formalism used for a construction of two-loop flavor singlet
exclusive evolution kernels in the MS bar scheme. The approach is based on the
known pattern of conformal symmetry breaking in MS bar as well as constraints
arising from the superconformal algebra of the N = 1 super Yang-Mills theory.


title: Technicolor Signatures---Ieri, Oggi e Domani

abstract:
  We briefly review the basic structure of modern--day technicolor theories. We
then discuss the signatures for technicolor as they were in its early days, the
searches that have been recently performed at the Tevatron and LEP colliders,
and the prospects for testing technicolor in Tevatron Run II and at the LHC.


title: Study of R-parity Violation at a mu-p Collider

abstract:
  To explore the discovery possibilities of a high-energy muon-proton collider,
we examine signals that could arise from direct-channel formation of
supersymmetric-particle resonances through operators that do not respect
R-parity.


title: Estimating sigma-meson couplings from D \to 3\pi decays

abstract:
  Using recent experimental evidence from E791 on the sigma meson in D \to 3\pi
decays, we study the relevant couplings in D \to \sigma \pi and \sigma \to \pi\
pi within the accepted theoretical framework for non leptonic D decays. We also
review the linear sigma model, finding that it gives a description which is
consistent with the experimental data.


title: K0-anti-K0 mixing in the 1/Nc expansion

abstract:
  We present the result for the invariant B_K factor of K0-anti-K0 mixing in
the chiral limit and to next-to-leading order in the 1/Nc expansion. We
explicitly demonstrate the cancellation of the renormalization scale and scheme
dependences between short- and long-distance contributions in the final
expression. Numerical estimates are then given, by taking into account
increasingly refined short- and long-distance constraints of the underlying QCD
Green's function which governs the B_K factor.


title: Anisotropic flow in ultra-relativistic heavy ion collisions

abstract:
  A sign reversal of the directed flow parameter $v_1$ in the central rapidity
region in Au+Au collisions at $\sqrt s =200$~AGeV is predicted. This anti-flow
is shown to be linked to the expansion of the hot matter created. In line with
this observation the predicted elliptic flow parameter $v_2$ of various
particle species is predicted and linked to the mean free path of these
particles.


title:
Uncertainties of Parton Distribution Functions and Their Implications on
  Physical Predictions

abstract:
  We describe preliminary results from an effort to quantify the uncertainties
in parton distribution functions and the resulting uncertainties in predicted
physical quantities. The production cross section of the $W$ boson is given as
a first example. Constraints due to the full data sets of the CTEQ global
analysis are used in this study. Two complementary approaches, based on the
Hessian and the Lagrange multiplier method respectively, are outlined. We
discuss issues on obtaining meaningful uncertainty estimates that include the
effect of correlated experimental systematic uncertainties and illustrate them
with detailed calculations using one set of precision DIS data.


title: Phenomenological aspects of nonstandard supersymmetry breaking terms

abstract:
  In realistic supersymmetric models, very small hard supersymmetry breaking
terms generally appear. Some of them violate baryon and/or lepton number. We
discuss their possible applications to proton decay and generation of neutrino
masses.


title:
Multi-boson effects in Bose-Einstein interferometry and the multiplicity
  distribution

abstract:
  Multi-boson symmetrization effects on two-particle Bose-Einstein
interferometry are studied for ensembles with arbitrary multiplicity
distributions. This generalizes the previously studied case of a Poissonian
input multiplicity distribution. In the general case we find interesting
residual correlations which require a modified framework for extracting
information on the source geometry from two-particle correlation measurements.
In sources with high phase-space densities, multi-boson effects modify the
Hanbury Brown-Twiss (HBT) radius parameters and simultaneously generate strong
residual correlations. We clarify their effect on the correlation strength
(intercept parameter) and thus explain a variety of previously reported
puzzling multi-boson symmetrization phenomena. Using a class of analytically
solvable Gaussian source models, with and without space-momentum correlations,
we present a comprehensive overview of multi-boson symmetrization effects on
particle interferometry. For event ensembles of (approximately) fixed
multiplicity, the residual correlations lead to a minimum in the correlation
function at non-zero relative momentum, which can be practically exploited to
search, in a model-independent way, for multi-boson symmetrization effects in
high-energy heavy-ion experiments.


title:
Gauge-invariant description of the electromagnetic field in the Higgs
  phase of the Standard Model

abstract:
  It is shown that the definition of the photon field in the broken-symmetry
phase of the electroweak theory proposed recently by O.T(ornkvist is equivalent
to that proposed previously by Vlasov et al.


title: Pythia version 7-0.0 - a proof-of-concept version

abstract:
  This document describes the first proof-of-concept version of the Pythia7
program.
  Pythia7 is a complete re-write of the Pythia program in C++. It is mainly
intended to be a replacement for the `Lund' family of event generators, but is
also a toolkit with a structure suitable for implementing any event generator
model.
  In this document, the structure of the program is presented both from the
user and the developer point of view. It is not intended to be a complete
manual, but together with the documentation provided in the distribution, it
should be sufficient to start working with the program.


title:
Off-Diagonal Generalized Vector-Dominance and Colour-Dipoles in Low-x
  DIS

abstract:
  We briefly summarize the equivalence of off-diagonal generalized vector
dominance and the colour-dipole approach to deep-inelastic scattering (DIS) in
the diffraction region of values of $x \simeq Q^2/W^2 << 1$.


title: NNLO evolution of deep-inelastic structure functions: the singlet case

abstract:
  We study the next-to-next-to-leading order (NNLO) evolution of flavour
singlet parton densities and structure functions in massless perturbative QCD.
Present information on the corresponding three-loop splitting functions is used
to derive parametrizations of these quantities, including Bjorken-x dependent
estimates of their residual uncertainties. Compact expressions are also
provided for the exactly known, but in part rather lengthy two-loop singlet
coefficient functions. The size of the NNLO corrections and their effect on the
stability under variations of the renormalization and mass-factorizations
scales are investigated. Except for rather low values of the scales, the
residual uncertainty of the three-loop splitting functions does not lead to
relevant effects for x > 10^-3. Inclusion of the NNLO contributions
considerably reduces the theoretical uncertainty of determinations of the quark
and gluon densities from deep-inelastic structure functions.


title: Overlapping Instantons

abstract:
  Overlapping instantons have an action density profile that significantly
deviates from the simple addition of the density profiles of single instantons.
This turns out to have important consequences for identifying the proper
instanton content of a given configuration. Most dramatic is the case where the
instantons are parallel in group space, leading to the effect of hiding large
instantons. Sufficiently large instantons can have important contributions to a
confining interaction.


title:
Field Correlators in Abelian-Projected Theories and Stochastic Vacuum
  Model

abstract:
  The bilocal electric field strength correlators in Abelian-projected SU(2)-
and SU(3)-theories are derived with accounting for the contributions to these
quantities brought about by the virtual vortex loops, built out of the dual
Nielsen-Olesen strings. Owing to the screening of magnetic charge of the dual
vector bosons in the gas of such loops, these bosons become heavier, which
leads to the respective change of the correlation length of the vacuum in the
models under study. Besides that, it turns out that such a screening leads also
to the appearance of the long-range contribution to one of the two coefficient
functions, which parametrize the bilocal correlator within the Stochastic
Vacuum Model. Finally, the modifications of the propagators of the dual vector
bosons, inspired by the correlation effects in the gas of vortex loops, are
also discussed.