title: New Physics in the Third Family and its Effect on Low Energy Data

abstract:
  We investigate, in detail, a model in which the third family fermions are
subjected to an SU(2) dynamics different from the first two families.
Constrained by the precision Z-pole data, the heavy gauge boson mass is bounded
from below to be about 1.7 TeV at the $2\sigma$ level. The flavor-changing
neutral current (FCNC) in the lepton sector can be significant in
$\tau\leftrightarrow e$ and $\tau \leftrightarrow \mu$ transitions. In the
latter case, the ratio $Br(\tau\to \mu \bar{\nu_\mu} \nu_\tau)/ Br(\tau\to e
\bar{\nu_e} \nu_\tau)$ and $Br(\tau\to \mu \mu \mu)$ can constrain the model
better than LEP/SLC data in some region of the parameter space. Furthermore,
FCNCs are unavoidable in the quark sector. Significant effects to the
$B^0-\bar{B^0}$ mixing and the rare decays of the K and B mesons, such as
$K^\pm \to \pi^\pm \nu {\bar \nu}$, $b \to s \nu {\bar \nu}, B_s \to
\tau^+\tau^-, \mu^+\mu^-$ and $B_{s,d} \to \mu^\pm \tau^\mp$, are expected.


title: Low x_{bj} DIS, QCD and Generalized Vector Dominance

abstract:
  We give a brief overview on the present status of Generalized Vector
Dominance as appplied to vector-meson production and the total photoabsorption
cross section in the region of small x_{bj}. We comment on how GVD originates
from QCD notions such as color transparency.


title: Two-hadron Inclusive DIS and Interference Fragmentation Functions

abstract:
  We investigate the properties of interference fragmentation functions arising
from the emission of two leading hadrons inside the same jet for semi-inclusive
lepton-nucleon deep-inelastic scattering. Using an extended spectator model we
give numerical estimates for the example of the fragmentation into a
proton-pion pair with its invariant mass on the Roper resonance.


title:
Observing H -> W*W* -> e mu pT(miss) in weak boson fusion with dual
  forward jet tagging at the LHC

abstract:
  Weak boson fusion promises to be a copious source of intermediate mass
Standard Model Higgs bosons at the LHC. The additional very energetic forward
jets in these events provide for powerful background suppression tools. We
analyze the H -> W^(*)W^(*) -> e mu pTmiss decay mode for a Higgs boson mass in
the 130-200 GeV range. A parton level analysis of the dominant backgrounds
(production of W pairs, tt~ and Z -> tau tau in association with jets)
demonstrates that this channel allows the observation of H -> W^(*)W^(*) in a
virtually background-free environment, yielding a significant Higgs boson
signal with an integrated luminosity of 5 fb^-1 or less. Weak boson fusion
achieves a much better signal to background ratio than inclusive H -> e mu
pTmiss and is therefore the most promising search channel in the 130-200 GeV
mass range.


title:
A direct evaluation of the Lambda_c^+ absolute branching ratios: a new
  approach

abstract:
  A novel method for a direct measurement of the exclusive Lambda_c^+ branching
ratios is here described. The approach is based on the peculiar topology of the
quasi-elastic charm neutrino-induced events on nucleons. The intrinsic
potentiality of the method is thoroughly discussed using a "perfect detector".
As an application, the statistical accuracy reachable with existing data sample
has been estimated. From a theoretical point of view, such measurement provides
a better understanding of the baryonic b-decays.


title: Color Coherent Phenomena with Hadron Beams

abstract:
  We outline major ideas involved in discussion of color coherence phenomena
(CCP) at intermediate energies. We point out that the recent advances in
calculating cross sections of hard exclusive processes off light nuclei allow
to use the lightest nuclei for sensitive tests of CCP. Consistency of the
results of the measurements of color transparency in quasielastic A(p,2p) and
A(e,e$'$p) processes is emphasized. Evidence for presence of significant color
fluctuations in nucleons and pions emerging from the study of diffractive
processes is summarized. A new class of hard processes leading to three
particle final state is suggested for electron and hadron projectiles. A number
of new experiments are suggested to probe color fluctuations in hadrons.


title:
CP Asymmetry for Inclusive Decay $B \to X_d + \gamma$ in the Minimal
  Supersymmetric Standard Model

abstract:
  We study the inclusive rare decay $B\to X_d+\gamma$ in the supergravity
inspired Minimal Supersymmetric Standard Model and compute the CP-asymmetry in
the decay rates. We show that there exist two phenomenologically acceptable
sets of SUSY parameters: for one set the CP-asymmetry has the same (positive)
sign as in the Standard Model and lies in the range (5-45)% while for the other
set it is negative with values within -(2-21)%.


title: The Small x Behaviour of Altarelli-Parisi Splitting Functions

abstract:
  We extract the small x asymptotic behaviour of the Altarelli-Parisi splitting
functions from their expansion in leading logarithms of 1/x. We show in
particular that the nominally next-to-leading correction extracted from the
Fadin-Lipatov kernel is enhanced asymptotically by an extra ln 1\x over the
leading order. We discuss the origin of this problem, its dependence on the
choice of factorization scheme, and its all-order generalization. We derive
necessary conditions which must be fulfilled in order to obtain a well behaved
perturbative expansion, and show that they may be satisfied by a suitable
reorganization of the original series.


title: Color gauge invariance in the Drell-Yan process

abstract:
  We consider the color gauge invariance of a factorized description of the
Drell-Yan process cross section. In particular, we focus on the next-to-leading
twist contributions for polarized scattering and on the cross section
differential in the transverse momentum of the lepton pair in the region where
the transverse momentum is small compared to the hard scale. The hadron tensor
is expressed in terms of manifestly color gauge invariant, nonlocal operator
matrix elements and a color gauge invariant treatment of soft gluon poles is
given. Also, we clarify the discrepancy between two published results for a
single spin asymmetry in the Drell-Yan cross section. This asymmetry arises if
such a soft gluon pole is present in a specific twist-three hadronic matrix
element.


title: Searching for R-Parity Violation at Run-II of the Tevatron

abstract:
  We present an outlook for possible discovery of supersymmetry with broken
R-parity at Run II of the Tevatron. We first present a review of the literature
and an update of the experimental bounds. In turn we then discuss the following
processes: 1. Resonant slepton production followed by R-parity violating decay,
(a) via $LQD^c$ and (b) via $LLE^c$. 2. How to distinguish resonant slepton
production from $Z'$ or $W'$ production. 3. Resonant slepton production
followed by the decay to neutralino LSP, which decays via $LQD^c$. 4. Resonant
stop production followed by the decay to a chargino, which cascades to the
neutralino LSP. 5. Gluino pair production followed by the cascade decay to
charm squarks which decay directly via $L_1Q_2D^c_1$. 6. Squark pair production
followed by the cascade decay to the neutralino LSP which decays via
$L_1Q_2D^c_1$. 7. MSSM pair production followed by the cascade decay to the LSP
which decays (a) via $LLE^c$, (b) via $LQD^c$, and (c) via $U^cD^cD^c$,
respectively. 8. Top quark and top squark decays in spontaneous R-parity
violation.


title:
Exploring the timelike region for the elastic form factor in the
  light-front quantization

abstract:
  Even though the Drell-Yan-West formulation is the most rigorous and
well-established framework to compute the exclusive processes, its utility has
been limited only to the spacelike region because of the intrinsic kinematic
constraint $q^+=0$. We present an explicit example demonstrating how one may
obtain the necessary information (i.e. nonvalence or so called Z-graph
contribution) in the timelike region of exclusive process without encountering
a formidable task of direct calculation that has hindered so far the progress
in this area. In the analysis of $q\bar{Q}$ bound state form factors using an
exactly solvable model of $(3+1)$ dimensional scalar field theory interacting
with gauge fields, the results analytically continued from the spacelike region
coincide exactly with the direct results in the timelike region. This example
verifies that the method of analytic continuation is capable of yielding the
effect of complicate nonvalence contributions. The meson peaks analogous to the
vector meson dominance(VMD) phenomena are also generated at the usual VMD
positions.


title:
A Relation on Gaugino Masses in a Supersymmetric SO(10)_GUT x SO(6)_H
  Unified Model

abstract:
  The doublet-triplet splitting problem in supersymmetric grand unified
theories is elegantly solved in a supersymmetric SO(10)_GUT x SO(6)_H model. In
this model, the gauginos in the supersymmetric standard model do not respect
the usual GUT gaugino mass relation. We point out that in spite of non-unified
gaugino masses there is one nontrivial relation among gaugino masses in the
model. Thus, it can be used to test the model in future experiments.


title: Twist-3 effects in polarized Drell-Yan and semi-inclusive DIS

abstract:
  Two twist-3 processes are discussed. We first present a simple estimate of
the longitudinal-transverse spin asymmetry in the polarized Drell-Yan process.
We next derive a cross section for the semi-inclusive production of a polarized
spin-1/2 baryon in the DIS of an unpolarized electron off the polarized
nucleon.


title: The exact parametrization of the neutrino mixing

abstract:
  We discuss the propagation and the flavour mixing of neutrinos in the context
of the Quantum Field Theory. We propose an exact parametrization of the
neutrino mixing matrix and its transformation in a simpler form which accounts
for a small $\nu_e - \nu_\mu$ and a large $\nu_\mu - \nu_\tau$ mixing. Finally,
we comment the differences between the charged quark and neutral lepton sector
and consider the physical situations that require this approach.


title:
Theoretical Summary: 1999 Electroweak Session of the Rencontres de
  Moriond

abstract:
  The following aspects of the electroweak interactions are discussed, based on
presentations here: the status of the Standard Model, CP violation, neutrino
masses and oscillations, supersymmetry and models in extra dimensions, and
future projects. Particular emphasis is laid on the tests of CP and CPT by KTeV
and CPLEAR, on the problems of degenerate neutrinos, on supersymmetric dark
matter, on future long-baseline neutrino beams, and on muon storage rings that
may be used as neutrino factories.


title: Detecting Heavy Charged Higgs Bosons at the LHC with Four b-Quark Tags

abstract:
  We investigate the signature of a heavy charged Higgs boson of the Minimal
Supersymmetric Standard Model in the lepton plus multi-jet channel at the Large
Hadron Collider with four $b$-tags. The signal is the gluon-gluon fusion
process $gg\to t\bar b H^-$, followed by the $H^-\to \bar t b$ decay, while the
main background is from $gg\to t\bar t b\bar b$. We find that the two can be
separated effectively by kinematic cuts and mass reconstruction, but the signal
size is not very large in the end. Nonetheless, with a good $b$-tagging
efficiency, $\epsilon_b\sim50%$, this channel can provide a viable signature
over a limited but interesting range of the parameter space.


title: Update of MRST partons

abstract:
  We discuss topical issues concerning the MRST parton analysis. We introduce
some new parton sets in order to estimate the uncertainty in the cross sections
predicted for W and Z production at the Tevatron and the LHC. We compare with
CTEQ5 partons.


title:
Bimaximal mixing from the leptonic new texture for triangular mass
  matrices

abstract:
  An analysis of the leptonic texture for the new triangular mass matrices has
been carried out. In particular, it is shown that both bimaximal and nearly
bimaximal solutions for solar and atmospheric neutrino anomalies can be
generated within this pattern. We have also derived exact and compact
parametrization of the leptonic mixing matrix in terms of the lepton masses and
the parameters $\alpha, \beta'$ and $\delta$. A consistency with the CHOOZ
reactor result for $V_m{_{13}}$ and a smallness of the Jarlskog's invariant
parameter are obtained.


title: Trilepton Signal for Supersymmetry at the Fermilab Tevatron Revisited

abstract:
  Within a wide class of models, the LEP2 lower limit of 95 GeV on the chargino
mass implies gluinos are heavier than $\sim$300 GeV. In this case electroweak
$\tw_1\twb_1$ and $\tw_1\tz_2$ production are the dominant SUSY processes at
the Tevatron, and the extensively examined isolated trilepton signal from
$\tw_1\tz_2$ production assumes an even greater importance. We update our
previous calculations of the SUSY reach of luminosity upgrades of the Fermilab
Tevatron in this channel incorporating ({\it i}) decay matrix elements in the
computation of the momenta of leptons from chargino and neutralino decays,
({\it ii}) the trilepton background from $W^*Z^*$ and $W^*\gamma^*$ production
which, though neglected in previous analyses, turns out to be the dominant
background, and finally, ({\it iii}) modified sets of cuts designed to reduce
these new backgrounds and increase the range of model parameters for which the
signal is observable. We show our improved projections for the reach for SUSY
of both the Fermilab Main Injector and the proposed TeV33 upgrade. We also
present opposite sign same flavor dilepton invariant mass distributions as well
as the $p_T$ distributions of leptons in SUSY trilepton events, and comment
upon how the inclusion of decay matrix elements impacts upon the Tevatron
reach, as well as upon the extraction of neutralino masses.


title:
Electroweak precision measurements and collider probes of the Standard
  Model with large extra dimensions

abstract:
  The elementary particles of the Standard Model may live in more than 3+1
dimensions. We study the consequences of large compactified dimensions on
scattering and decay observables at high-energy colliders. Our analysis
includes global fits to electroweak precision data, indirect tests at
high-energy electron-positron colliders (LEP2 and NLC), and direct probes of
the Kaluza-Klein resonances at hadron colliders (Tevatron and LHC). The present
limits depend sensitively on the Higgs sector, both the mass of the Higgs boson
and how many dimensions it feels. If the Higgs boson is trapped on a 3+1
dimensional wall with the fermions, large Higgs masses (up to 500 GeV) and
relatively light Kaluza-Klein mass scales (less than 4 TeV) can provide a good
fit to precision data. That is, a light Higgs boson is not necessary to fit the
electroweak precision data, as it is in the Standard Model. If the Higgs boson
propagates in higher dimensions, precision data prefer a light Higgs boson
(less than 260 GeV), and a higher compactification scale (greater than 3.8
TeV). Future colliders can probe much larger scales. For example, a 1.5 TeV
electron-positron linear collider can indirectly discover Kaluza-Klein
excitations up to 31 TeV if 500 fb^-1 integrated luminosity is obtained.


title: One-loop flavor changing electromagnetic transitions

abstract:
  We discuss the effect of the external fermion masses in the flavor-changing
radiative transitions of a heavy fermion (quark or lepton) to a lighter fermion
at the one-loop level, and point out an often overlooked crucial difference in
the sign of a charge factor between transitions of the down type $s\to d\gamma$
and the up type $c\to u\gamma$. We give formulas for the $F\to f\gamma$
effective vertex in various approximations and the exact formula for $t\to
c\gamma$ and $\tau \to \mu \gamma$.


title: 1/Q^2 corrections in DIS fragmentation functions

abstract:
  We present results of recent calculations of power corrections to
single-hadron inclusive momentum distributions in the current hemisphere of the
Breit frame in DIS. Though results are presented for both singlet and
non-singlet scattering contributions, we emphasise the fact that the former is
dominant in the kinematical region studied at HERA.


title:
Quark-antiquark Bethe-Salpeter formalism, spectrum and Regge
  Trajectories

abstract:
  Starting from a path integral representation of appropriate 4-point and
2-point gauge invariant Green functions and from the "Modified Area Law" model
for the evaluation of the Wilson loop, a q \bar q Bethe-Salpeter like equation
and a related Schwinger-Dyson equation can be obtained. From such equations an
effective relativistic Hamiltonian can be derived by standard methods and then
applied to the determination of the meson spectrum. The entire known
heavy-heavy and heavy-light spectra and the lowest light-light Regge
trajectories are rather well reproduced in terms of four parameters alone, the
light quark masses being fixed a priori on typical current values.


title: Low Scale Unification, Newton's Law and Extra Dimensions

abstract:
  Motivated by recent work on low energy unification, in this short note we
derive corrections on Newton's inverse square law due to the existence of extra
decompactified dimensions. In the four-dimensional macroscopic limit we find
that the corrections are of Yukawa type. Inside the compactified space of
n-extra dimensions the sub-leading term is proportional to the (n+1)- power of
the distance over the compactification radius ratio. Some physical implications
of these modifications are briefly discussed.


title:
Ruling out a higher spin field solution to the cosmological constant
  problem

abstract:
  We consider the modification of Newton's gravity law in Dolgov's higher spin
models designed to compensate the cosmological constant. We find that the
effective Planck mass is unacceptably large in these models. We also point out
that the properties of gravitational waves are entirely different in these
models as compared to general relativity.


title:
Constraints on Light Pseudoscalars Implied by Tests of the Gravitational
  Inverse-Square Law

abstract:
  The exchange of light pseudoscalars between fermions leads to a
spin-independent potential in order g^4, where g is the Yukawa
pseudoscalar-fermion coupling constant. This potential gives rise to detectable
violations of both the weak equivalence principle (WEP) and the gravitational
inverse-square law (ISL), even if g is quite small. We show that when
previously derived WEP constraints are combined with those arisingfrom ISL
tests, a direct experimental limit on the Yukawa coupling of light
pseudoscalars to neutrons can be inferred for the first time (g_n^2/4pi < 1.6
\times 10^-7), along with a new (and significantly improved) limit on the
coupling of light pseudoscalars to protons.


title: Hypermagnetic Knots, Chern-Simons Waves and the Baryon Asymmetry

abstract:
  At finite hyperconductivity and finite fermionic density the flux lines of
long range hypermagnetic fields may not have a topologically trivial structure.
The combined evolution of the chemical potentials and of pseudoscalar fields
(like the axial Higgs), possibly present for temperatures in the TeV range, can
twist the hypercharge flux lines, producing, ultimately, hypermagnetic knots
(HK). The dynamical features of the HK depend upon the various particle physics
parameters of the model (pseudoscalar masses and couplings, strength of the
electroweak phase transition, hyperconductivity of the plasma) and upon the
magnitude of the primordial flux sitting in topologically trivial
configurations of the hypermagnetic field. We study different cosmological
scenarios where HK can be generated. We argue that the fermionic number sitting
in HK can be released producing a seed for the Baryon Asymmetry of the Universe
(BAU) provided the typical scale of the knot is larger than the diffusivity
length scale. We derive constraints on the primordial hypermagnetic flux
required by our mechanism and we provide a measure of the parity breaking by
connecting the degree of knottedness of the flux lines to the BAU. We rule out
the ordinary axion as a possible candidate for production (around temperatures
of the order of the GeV) of {\em magnetic} knots since the produced {\em
electromagnetic} helicity is negligible (for cosmological standard) if the
initial amplitude of the axion oscillations is of the order of the Peccei-Quinn
breaking scale.


title: QCD critical point: what it takes to discover

abstract:
  This report summarizes the results of the work done in collaboration with K.
Rajagopal and E. Shuryak. We analyze the physics behind the event-by-event
fluctuations in heavy ion collisions. Using thermodynamic description of the
ensemble of events we analyze and quantify various effects that are sensitive
to the proximity of the critical point on the phase diagram of QCD.


title: The Dirac-Hestenes Lagrangian

abstract:
  We discuss the variational principle within Quantum Mechanics in terms of the
noncommutative even Space Time sub-Algebra, the Clifford $\Ra$-algebra
$Cl_{1,3}^+$. A fundamental ingredient, in our multivectorial algebraic
formulation, is the adoption of a $\D $-complex geometry, $\D \equiv span_{\RR}
\{1,\gamma_{21} \}$, $\gamma_{21} \in Cl_{1,3}^+$. We derive the Lagrangian for
the Dirac-Hestenes equation and show that such Lagrangian must be mapped on $\D
\otimes {\cal F}$, where $\cal F$ denotes an $\Ra$-algebra of functions.


title: Neutrino Mass and Oscillation

abstract:
  The question of neutrino mass is one of the major riddles in particle
physics. Recently, strong evidence that neutrinos have nonzero masses has been
found. While tiny, these masses could be large enough to contribute
significantly to the mass density of the universe. The evidence for
nonvanishing neutrino masses is based on the apparent observation of neutrino
oscillation -- the transformation of a neutrino of one type or "flavor" into
one of another. We explain the physics of neutrino oscillation, and review and
weigh the evidence that it actually occurs in nature. We also discuss the
constraints on neutrino mass from cosmology and from experiments with negative
results. After presenting illustrative neutrino mass spectra suggested by the
present data, we consider how near- and far-future experiments can further
illuminate the nature of neutrinos and their masses.


title:
Enhanced contribution to quark and neutron electric dipole moments with
  small mixing of right-handed currents and CKM CP violation

abstract:
  We study the light quark and the neutron electric dipole moments (EDMs) under
the assumptions that the CP source is still in the usual CKM matrix and that
there is a small mixing of right-handed charged currents in the quark sector.
We find that the EDMs arise already at two loop order that are much larger than
the standard model (SM) result even for a small mixing.


title: Off Mass Shell Effects in Hadron Electric Dipole Moments

abstract:
  We note that off the quark mass shell the operators $(p_i+p_f)_\mu\gamma_5$
and $i\sigma_{\mu\nu}(p_i -p_f)^\nu\gamma_5$, both of which reduce to
$-\vec{\sigma}\cdot\vec{E}$ in the non-relativistic limit, are no longer
identical. In this paper we explore the effects of this difference in the
contribution of these quark electric moments to hadronic electric moments.


title: Fine structure splittings of excited P and D states in charmonium

abstract:
  It is shown that the fine structure splittings of the $2 ^3P_J$ and $3 ^3P_J$
excited states in charmonium are as large as those of the $1^3P_J$ state if the
same $\alpha_s(\mu)\approx 0.36$ is used. The predicted mass $M(2 ^3P_0)=3.84$
GeV appears to be 120 MeV lower that the center of gravity of the $2 ^3P_J$
multiplet and lies below the $D\bar D^*$ threshold. Our value of $M(2 ^3P_0)$
is approximately 80 MeV lower than that from the paper by Godfrey and Isgur
while the differences in the other masses are $\la 20$ MeV. Relativistic
kinematics plays an important role in our analysis.


title:
On the Ter-Mikaelian and Landau--Pomeranchuk effects for induced soft
  gluon radiation in a QCD medium

abstract:
  The polarization of a surrounding QCD medium modifies the induced gluon
radiation spectrum of a high-energy parton at small transverse momenta for a
single interaction and for multiple scatterings as well. This effect is an
analogue of the Ter-Mikaelian effect in QED, superimposed to the
Landau--Pomeranchuk effect, however it appears in QCD in a different phase
space region.


title:
Structure of the Light Scalar Mesons from a Coupled Channel Analysis of
  the s-wave pi pi - k kbar Scattering

abstract:
  The analysis of the poles of the $\pi\pi$ scattering amplitude is shown to
favour a dynamical origin of the sigma meson: it is created by a strongly
attractive $\pi\pi$ interaction in the $J^{PC}=0^{++}I=0$ channel. In the limit
$N_c\to\infty$, the $\sigma$ meson disappears, contrary to the case of
conventional $q\bar{q}$ states. Implications for the search of the scalar
$q\bar{q}$ and glueball states are discussed.


title: Explicit expressions of spin wave functions

abstract:
  We derive the explicit expressions of the canonical and helicity wave
functions for massive particles with arbitrary spins. Properties of these wave
functions are discussed.


title: Summary of the NOW'98 Phenomenology Working Group

abstract:
  Summary of the Phenomenology Working Group at the Europhysics Neutrino
Oscillation Workshop (NOW'98), 7-9 September 1998, Amsterdam.


title: Spin Correlations in Top Quark Production at e^+ e^- Linear Colliders

abstract:
  The object of this thesis is to study the spin-spin correlations for top
quark productions and their decay at polarized e^+e^- linear colliders. For the
analyses of the spin-spin correlations in top quark production, we introduce a
generic spin basis and show which spin basis is the most optimal. We discuss
the spin-angular correlations for the top quark decay, and demonstrate that the
directions of electro-weak decay products of polarized top quarks are strongly
correlated to the top quark spin. We also explain how to measure the top quark
spin using decay products. The spin correlations using the generic spin basis
are extensively studied at the next to leading order of QCD for top quark
productions at e^+e^- colliders. The radiative corrections induce an anomalous
\gamma/Z magnetic moment for the top quarks and allow for real gluon emissions.
Therefore they might change the leading order analyses. We show that higher
order effects on the top quark spin orientation are very small. The final
results are that the top (or anti-top) quarks are produced in an essentially
unique spin configuration for a particular spin basis even after including the
{\cal O}(\alpha_{s}) QCD corrections. Our results imply that measuring the spin
correlation for top quarks is very promising to reveal new aspects of the
Standard Model, as well as new physics beyond the Standard Model.


title: Heavy Majorana neutrino production at electron-muon colliders

abstract:
  Possibilities for detecting heavy Majorana neutrinos ($N$'s) at future
$e{\mu}$ colliders are investigated. In contrast to the $e^-e^+$ colliders
(LEP200 and NLC), the center-of-mass (CMS) energies achieved at $e{\mu}$
colliders can be much higher and the $Z$-mediated $s$ channel is excluded
automatically. This opens the attractive possibility of having high production
cross sections for $N$'s and at the same time probing only the strength of
charged current couplings of $N$'s ($NWe$ and $NW{\mu}$). The production cross
sections and the expected numbers of events for the reaction $e^{\mp}
{\mu}^{\pm} \to NN \to W^{\pm} {\ell}^{\mp} W^{\pm} {\ell}^{\prime \mp}$ are
calculated for various masses $M$ of the Majorana neutrinos and for the CMS
energies $\sqrt{s} = 0.5-6.0$ TeV. The values of the charged current coupling
parameters are set equal to their present upper bounds. We obtain reasonably
high production cross sections. Further, the effects of the off-shell
intermediate $N$'s turn out to be significant only at $\sqrt{s}
\stackrel{>}{\approx} 2$ TeV.


title: Charmonium production at neutrino factories

abstract:
  At existing and planned neutrino factories (high energy and high intensity
neutrino beam facilities) precision studies of QCD in neutrino-nucleon
interactions are a realistic opportunity. We investigate charmonium production
in fixed target neutrino experiments. We find that $J/\psi$ production in
neutrino-nucleon collision is dominated by the color octet $^3S_1$ NRQCD matrix
element in a neutral current process, which is not accessible in photo or
leptoproduction. Neutrino experiments at a future Muon Collider will acquire
sufficient event rate to accurately measure color octet matrix element
contributions. The currently running high energy neutrino experiments, NOMAD
and NuTeV could also observe several such events.


title:
Pair production of light pseudoscalar particles in strong inhomogeneous
  fields by the Schwinger mechanism

abstract:
  We calculate the rate for pair production of light pseudoscalars by strong
inhomogeneous and static electric (magnetic) fields. We show that, in the case
of axions, the stability of atoms over cosmic lifetimes is jeopardised unless
the Peccei-Quinn symmetry breaking scale $f_a$ is larger than ${\cal O}
(10^{10} GeV)$.


title:
Approximate Analytic Solutions of RG Equations for Yukawa and Soft
  Couplings in SUSY Models

abstract:
  We present simple analytical formulae which describe solutions of the RG
equations for Yukawa couplings in SUSY gauge theories with the accuracy of a
few per cent. Performing the Grassmannian expansion in these solutions one
finds those for all the soft couplings and masses. The solutions clearly
exhibit the fixed point behaviour which can be calculated analytically. A
comparison with numerical solutions is demonstrated.


title: Transverse Momentum Dependence of the Landau-Pomeranchuk-Migdal Effect

abstract:
  We study the transverse momentum dependence of the Landau-Pomeranchuk-Migdal
effect in QED, starting from the high energy expansion of the solution of the
Dirac equation in the presence of an external field. The angular integrated
energy loss formula differs from an earlier expression of Zakharov by taking
finite kinematical boundaries into account. In an expansion in powers of the
opacity of the medium, we derive explicit expressions for the radiation cross
section associated with N=1, 2 and 3 scatterings. We verify the Bethe-Heitler
and the factorization limit, and we calculate corrections to the factorization
limit proportional to the square of the target size. A closed form expression
valid to arbitrary orders in the opacity is derived in the dipole
approximation. The resulting radiation spectrum is non-analytic in the coupling
constant which is traced back to the transverse momentum broadening of a hard
parton undergoing multiple small angle Moliere scattering. In extending the
results to QCD, we test a previously used dipole prescription by comparing to
direct pQCD results for N=1 and 2. For N=1, the QCD dipole prescription
reproduces exactly the Bertsch-Gunion radiation spectrum. For N=2, we find a
sizeable correction which reduces to a multiplicative factor 17/8 at large
separation.


title: Quasiparticle description of deconfined matter at finite mu and T

abstract:
  An effective quasiparticle description of deconfined QCD thermodynamics
compatible with both finite temperature nonperturbative lattice data and the
asymptotic limit is generalized to finite chemical potential. Implications for
the N_f = 4 flavor lattice data extended to mu \neq 0 as well as for deconfined
matter with realistic quark masses are considered.


title: Classical Sphaleron Rate on Fine Lattices

abstract:
  We measure the sphaleron rate for hot, classical Yang-Mills theory on the
lattice, in order to study its dependence on lattice spacing. By using a
topological definition of Chern-Simons number and going to extremely fine
lattices (up to beta=32, or lattice spacing a = 1 / (8 g^2 T)) we demonstrate
nontrivial scaling. The topological susceptibility, converted to physical
units, falls with lattice spacing on fine lattices in a way which is consistent
with linear dependence on $a$ (the Arnold-Son-Yaffe scaling relation) and
strongly disfavors a nonzero continuum limit. We also explain some unusual
behavior of the rate in small volumes, reported by Ambjorn and Krasnitz.


title:
Static Potential in the SU(2)-Higgs Model and Coupling Constant
  Definitions in Lattice and Continuum Models

abstract:
  We present a one-loop calculation of the static potential in the SU(2)-Higgs
model. The connection to the coupling constant definition used in lattice
simulations is clarified. The consequences in comparing lattice simulations and
perturbative results for finite temperature applications are explored.


title:
Hard exclusive production of two pions: Dipion mass distributions in
  gamma* N -->pi pi N and gamma* gamma --> pi pi

abstract:
  The leading twist parametrization of dipion mass distribution in hard
exclusive reactions is proposed. Its parameters are related to quark
distributions (usual and skewed) in the pion and to distributions amplitudes of
mesons ($\pi$, $\rho$, etc.). We show that measurements of the shape of dipion
mass distribution in hard exclusie reactions can give important information
about partonic structure of the pion. The expression for the amplitude of the
reaction $\gamma^*\gamma\to \pi\pi$ near the threshold in terms of singlet
quark distribution in the pion is presented.


title:
Past electron-positron g-2 experiments yielded sharpest bound on CPT
  violation for point particles

abstract:
  In our past experiments on a single electron and positron we measured the
cyclotron and spin-cyclotron difference frequencies omega_c and omega_a and the
ratios a = omega_a/ omega_c at omega_c = 141 Ghz for e^- and e^+ and later,
only for e^-, also at 164 Ghz. Here, we do extract from these data, as had not
done before, a new and very different figure of merit for violation of CPT
symmetry, one similar to the widely recognized impressive limit |m_Kaon -
m_Antikaon|/m_Kaon < 10^-18 for the K-mesons composed of two quarks. That
expression may be seen as comparing experimental relativistic masses of
particle states before and after the C, P, T operations had transformed
particle into antiparticle. Such a similar figure of merit for a non-composite
and quite different lepton, found by us from our Delta a = a^- - a^+ data, was
even smaller, h_bar |omega_a^- - omega_a^+|/2m_0 c^2 = |Delta a| h_bar
omega_c/2m_0 c^2) < 3(12) 10^-22.


title: How Penguins Started to Fly

abstract:
  A mechanism explaining a strong enhancement of nonleptonic weak decays was
suggested in 1975, later to be dubbed the penguin. This mechanism extends
Wilson's ideas about the operator product expansion at short distances and
reveals an intricate interplay of subtle features of the theory such as heavy
quark masses in Glashow-Iliopoulos-Maini cancellation, light quarks shaping the
chiral properties of QCD, etc. The penguins have subsequently evolved to play a
role in a variety of fields in present-day particle phenomenology. I will
describe the history of this idea and review its subsequent development. The
recent measurement of direct CP violation in K decays gives a new confirmation
of the penguin mechanism.


title: Gluon Condensate and Beyond

abstract:
  We review briefly and in retrospect the development which brought about the
QCD sum rules based on introduction of the gluon condensate (M.A. Shifman, A.I.
Vainshtein, and V.I. Zakharov (1978)).


title: Leptogenesis in Theories with Large Extra Dimensions

abstract:
  We study the scenario of baryogenesis through leptogenesis in
higher-dimensional theories, in which the scale of quantum gravity is many
orders of magnitude smaller than the usual Planck mass. The minimal realization
of these theories includes an isosinglet neutrino which feels the presence of
large compact dimensions, whereas all the SM particles are localized on a
$(1+3)$-dimensional subspace. In the formulation of minimal leptogenesis
models, we pay particular attention to the existence of Majorana spinors in
higher dimensions. After compactification of the extra dimensions, we obtain a
tower of Majorana Kaluza-Klein excitations which act as an infinite series of
CP-violating resonators, and derive the necessary conditions for their
constructive interference. Based on this CP-violating mechanism, we find that
the decays of the heavy Majorana excitations can produce a leptonic asymmetry
which is reprocessed into the observed baryonic asymmetry of the Universe by
means of out-of-equilibrium sphaleron interactions, provided the reheat
temperature is above 5 GeV.


title:
Bounds on Kaluza-Klein excitations of the SM vector bosons from
  electroweak tests

abstract:
  Within a minimal extension of the SM in 4+1 dimensions, we study how Kaluza
Klein excitations of the SM gauge bosons affect the electroweak precision
observables. Asymmetries in Z decays provide the dominant bound on the
compactification scale M of the extra dimension. If the higgs is so light that
will be discovered at LEP2, we find the following 95% CL bounds: M > 3.5 TeV
(if the higgs lives in the extra dimension) and M > 4.3 TeV (if the higgs is
confined to our 4 dimensions). In the second case Kaluza Klein modes give
"universal"corrections and a good fit of precision data can be obtained with an
heavier higgs (up to 500 GeV) and with a smaller M > 3.4 TeV.


title:
The $a_0(980)$, $a_0(1450)$ and $K_0^*(1430)$ Scalar Decay Constants and
  the Isovector Scalar Spectrum

abstract:
  The isovector scalar correlator is studied using a class of finite energy sum
rules shown recently to be very well satisfied in the vector isovector channel.
The values of the $a_0$ scalar decay constants extracted in this analysis,
which describe the couplings of the $a_0(980)$ and $a_0(1450)$ to the isovector
scalar current, are shown to be comparable, strongly disfavoring any scenario
in which the $a_0(980)$ is interpreted as a loosely bound $K\bar{K}$ molecule
and the $a_0(1450)$ is assigned to the same flavor multiplet as the
$K_0^*(1430)$. The $a_0$ decay constants are also compared to the analogous
decay constant describing the coupling of the $K_0^*(1430)$ to the divergence
of the strange vector current (which may be obtained from experimental $K_{e3}$
and $K\pi$ phase shift data), and implications of the relative magnitudes for
the interpretation of the nature of the $a_0$ states discussed.


title:
FCNC top quark decay in the MSSM: a door to SUSY physics in high
  luminosity colliders?

abstract:
  We study the FCNC top quark decays t -> c h in the framework of the MSSM,
where h= h^0,H^0,A^0 is any of the supersymmetric neutral Higgs bosons. We
include the leading set of SUSY-QCD and SUSY electroweak contributions. While
the FCNC top quark decay into the SM Higgs boson has such a negligible rate
that will not be accessible to any presently conceivable accelerator, we find
that there is a chance that the potential rates in the MSSM can be measured at
the high luminosity colliders round the corner, especially at the LHC and
possibly at a future LC, but we deem it difficult at the upgraded Tevatron. In
view of the large SUSY-QCD effects that we find in the Higgs channels, and due
to some discrepancies in the literature, we have revisited the FCNC top quark
decay into gluon, t -> c g, in our framework. We confirm that the possibility
of sizeable rates does not necessarily require a general pattern of
gluino-mediated FCNC interactions affecting both the LH and the RH sfermion
sectors -- the LH one being sufficient. However, given the present bounds on
sparticle masses, the gluon channel turns out to lie just below the expected
experimental sensibility, so our general conclusion is that the Higgs channels
t -> c h (especially the one for the light CP-even Higgs) have the largest
potential top quark FCNC rates in the MSSM, namely of order 10^-4.


title: Isospin Violation in ${\bf B\to \pi\pi}$ Decays

abstract:
  An isospin analysis of $B\to \pi\pi$ decays yields $\sin 2\alpha$, where
$\alpha$ is the usual CKM angle $\alpha\equiv {\rm arg} [-V_{td}
V_{tb}^\ast/(V_{ud}V_{ub}^\ast)]$ without hadronic uncertainty if isospin is a
perfect symmetry. Yet isospin symmetry is broken not only by electroweak
effects but also by the $u$ and $d$ quark mass difference --- the latter drives
$\pi^0-\eta,\eta'$ mixing and converts the isospin-perfect triangle relation
between the $B\to \pi\pi$ amplitudes to a quadrilateral. The error incurred in
$\sin 2\alpha$ through the neglect of the resulting isospin-violating effects
can be significant, particularly if $\sin 2\alpha$ is small.


title:
A study of SUSY signatures at the Tevatron in models with near mass
  degeneracy of the lightest chargino and neutralino

abstract:
  For some choices of soft SUSY-breaking parameters, the LSP is a stable
neutralino $\cnone$, the NLSP is a chargino $\cpmone$ almost degenerate in mass
with the LSP ($\dmchi\equiv\mcpmone-\mcnone\sim \mpi-$few GeV), and all other
sparticles are relatively heavy. In this case, detection of sparticles in the
usual, mSUGRA-motivated signals will be difficult, since the decay products in
$\cpmone\to\cnone...$ will be very soft, and alternative signals must be
considered. Here, we study the viability of signatures at the Tevatron based on
highly-ionizing charged tracks, disappearing charged tracks, large impact
parameters, missing transverse energy and a jet or a photon, and determine the
mass reach of such signatures assuming that only the $\cpmone$ and $\cnone$ are
light. We also consider the jet+$\etmiss$ and $\gamma+\etmiss$ signatures
assuming that the gluino is also light with $\mgl\sim \mcpmone$. We find that
the mass reach is critically dependent upon $\dmchi$ and $\mgl-\mcpmone$. If
$\dmchi$ is sufficiently big that $c\tau(\cpmone)\lsim$few cm and $\mgl$ is
large, there is a significant possibility that the limits on $\mcpmone$ based
on LEP2 data cannot be extended at the Tevatron. If $c\tau(\cpmone)>$few cm,
relatively background-free signals exist that will give a clear signal of
$\cpmone$ production (for some range of $\mcpmone$) even if $\mgl$ is very
large.


title:
Supersymmetry, local horizontal unification, and a solution to the
  flavor puzzle

abstract:
  Supersymmetric gauge models with local horizontal symmetries are known to
generate large flavor changing neutral current effects induced by supersymmetry
breaking D-terms. We show how the presence of a U(1) gauge symmetry solves this
problem. We then construct a realistic gauge model with SU(2)_H x U(1)_H as the
local horizontal symmetry and suggest that the U(1)_H factor may be identified
with the anomalous U(1) induced by string compactification. This model explains
the observed hierarchies among the quark masses and mixing angles, accommodates
naturally the solar and atmospheric neutrino data, and provides simultaneously
a solution to the supersymmetric flavor problem. The model can be excluded if
the rare decay \mu --> e \gamma is not observed in the current round of
experiments.


title: Dissipative contributions to epsilon'/epsilon

abstract:
  The time evolution and decay of the neutral kaon system can be described
using quantum dynamical semigroups. Non-standard terms appear in the expression
of relevant observables; they can be parametrized in terms of six, new
phenomenological constants. We discuss how the presence of these constants
affects the determination of the parameter epsilon'/epsilon.


title: Second Order QCD Corrections to $\Gamma(t \to Wb)$

abstract:
  Corrections of $O(\alpha_s^2)$ to the decay of the top quark into a W boson
and a bottom quark are calculated. The method is based on an expansion of the
top quark propagator for small external momentum, q, as compared to the top
quark mass, M_t. The physical point q^2 = M_t^2 is reached through Pad\'e
approximations. The described method allows to take effects induced by a finite
W boson mass into account. The numerical relevance of the result is discussed.
Important cross-checks against recent results for the decay rate $b \to u l
\bar\nu$ and the two-loop QED corrections to $\mu$-decay are performed.


title: Searching for New Physics in Non-Leptonic B Decays

abstract:
  We present allowed regions in the space of observables of certain
non-leptonic B-meson decays that characterize these modes within the Standard
Model. A future measurement of observables lying significantly outside of these
regions would indicate the presence of new physics. Making use of SU(3)
arguments, we give the range for $B\to\pi K$ decays, and for the system of
$B_d\to\pi^+\pi^-$, $B_s\to K^+K^-$ modes.


title: Neutrinoless double-beta decay with three or four neutrino mixing

abstract:
  Considering the scheme with mixing of three neutrinos and a mass hierarchy
that can accommodate the results of solar and atmospheric neutrino experiments,
it is shown that the results of solar neutrino experiments imply a lower bound
for the effective Majorana mass in neutrinoless double-beta decay, under the
natural assumptions that massive neutrinos are Majorana particles and there are
no unlikely fine-tuned cancellations among the contributions of the different
neutrino masses. Considering the four-neutrino schemes that can accommodate
also the results of the LSND experiment, it is shown that only one of them is
compatible with the results of neutrinoless double-beta decay experiments and
with the measurement of the abundances of primordial elements produced in
Big-Bang Nucleosynthesis. It is shown that in this scheme, under the
assumptions that massive neutrinos are Majorana particles and there are no
cancellations among the contributions of the different neutrino masses, the
results of the LSND experiment imply a lower bound for the effective Majorana
mass in neutrinoless double-beta decay.


title:
QCD running coupling effects for the non-singlet structure function at
  small x

abstract:
  A generalization of the leading-order DGLAP evolution at small x is performed
for the non-singlet structure function by resumming the leading-order DGLAP
anomalous dimension to all orders in the QCD coupling. Explicit expressions are
obtained for the non-singlet structure function of the deep inelastic
scattering, taking into account both the double-logarithmic and the
single-logarithmic contributions, including the running alpha_s effects. It is
shown that when these contributions are included, the asymptotic small-x
behaviour is power-like, with an exponent of about 0.4.


title:
Monte Carlo Program KoralW 1.42 for All Four-Fermion Final States in
  e+e- Collisions

abstract:
  The Monte Carlo program KoralW version 1.42 is presented. It generates all
four-fermion final states with multibranch dedicated Monte Carlo pre-samplers
and complete, massive, Born matrix elements. The presamplers cover the entire
phase space. Multiphoton bremsstrahlung is implemented in the ISR approximation
within the YFS formulation with the O(alpha**3) leading-log matrix element. The
anomalous WWV couplings are implemented in CC03 approximation. The standard
decay libraries (JETSET, PHOTOS, TAUOLA) are interfaced. The semi-analytical
CC03-type code KorWan for differential and total cross-sections is included.


title: NLL BFKL and NNLO

abstract:
  The BFKL resummation at LL and NLL accuracy is briefly reviewed, with
particular emphasis on the connection between the NLL corrections to the BFKL
equation and exact NNLO calculations.


title:
QCD determination of the axial-vector coupling of the nucleon at finite
  temperature

abstract:
  A thermal QCD Finite Energy Sum Rule (FESR) is used to obtain the temperature
dependence of the axial-vector coupling of the nucleon, $g_{A}(T)$. We find
that $g_{A}(T)$ is essentially independent of $T$, in the very wide range $0
\leq T \leq 0.9 T_{c}$, where $T_{c}$ is the critical temperature. While
$g_{A}$ at T=0 is $q^{2}$-independent, it develops a $q^{2}$ dependence at
finite temperature. We then obtain the mean square radius associated with
$g_{A}$ and find that it diverges at $T=T_{c}$, thus signalling quark
deconfinement. As a byproduct, we study the temperature dependence of the
Goldberger-Treiman relation.


title:
Semi-Inclusive Hadron Production at HERA: the Effect of QCD Gluon
  Resummation

abstract:
  We present a formalism that improves the applicability of perturbative QCD in
the current region of semi-inclusive deep inelastic scattering. The formalism
is based on all-order resummation of large logarithms arising in the
perturbative treatment of hadron multiplicities and energy flows in this
region. It is shown that the current region of semi-inclusive DIS is similar to
the region of small transverse momenta in vector boson production at hadron
colliders. We use this resummation formalism to describe transverse energy
flows and charged particle multiplicity measured at the electron-proton
collider HERA. We find good agreement between our theoretical results and
experimental data for the transverse energy flows.


title:
Theoretical Constraints on the Vacuum Oscillation Solution to the Solar
  Neutrino Problem

abstract:
  The vacuum oscillation (VO) solution to the solar anomaly requires an
extremely small neutrino mass splitting, Delta m^2_{sol}\leq 10^{-10} eV^2. We
study under which circumstances this small splitting (whatever its origin) is
or is not spoiled by radiative corrections. The results depend dramatically on
the type of neutrino spectrum. If m_1^2 \sim m_2^2 \geq m_3^2, radiative
corrections always induce too large mass splittings. Moreover, if m_1 and m_2
have equal signs, the solar mixing angle is driven by the renormalization group
evolution to very small values, incompatible with the VO scenario (however, the
results could be consistent with the small-angle MSW scenario). If m_1 and m_2
have opposite signs, the results are analogous, except for some small (though
interesting) windows in which the VO solution may be natural with moderate
fine-tuning. Finally, for a hierarchical spectrum of neutrinos, m_1^2 << m_2^2
<< m_3^2, radiative corrections are not dangerous, and therefore this scenario
is the only plausible one for the VO solution.


title: Tensor glueball-meson mixing phenomenology

abstract:
  The overpopulated isoscalar tensor states are sifted using Schwinger-type
mass relations. Two solutions are found: one where the glueball is the
fJ(2220), and one where the glueball is more distributed, with f2(1820) having
the largest component. The f2(1565) and fJ(1710) cannot be accommodated as
glueball-(hybrid) meson mixtures in the absense of significant coupling to
decay channels. f2'(1525) -> pi pi is in agreement with experiment. The
fJ(2220) decays neither flavour democratically nor is narrow.


title: Strategy towards Mirror-fermion Signatures

abstract:
  The existence of mirror fermions interacting strongly under a new gauge group
and having masses near the electroweak scale has been recently proposed as a
viable alternative to the standard-model Higgs mechanism. The main purpose of
this work is to investigate which specific experimental signals are needed to
clearly differentiate the mirror-fermion model from other new-physics models.
In particular, the case is made for a future large lepton collider with c.o.m.
energies of roughly 4 TeV or higher.


title:
Hard scattering factorization and light cone hamiltonian approach to
  diffractive processes

abstract:
  We describe diffractive deeply inelastic scattering in terms of diffractive
parton distributions. We investigate these distributions in a hamiltonian
formulation that emphasizes the spacetime picture of diffraction scattering.
For hadronic systems with small transverse size, diffraction occurs
predominantly at short distances and the diffractive parton distributions can
be studied by perturbative methods. For realistic, large-size systems we
discuss the possibility that diffractive parton distributions are controlled
essentially by semihard physics at a scale of nonperturbative origin of the
order of a GeV. We find that this possibility accounts for two important
qualitative aspects of the diffractive data from HERA: the flat behavior in
beta and the delay in the fall-off with Q^2.


title: Correlator of Topological Charge Densities in Instanton Model in QCD

abstract:
  The QCD sum rule for the correlator of topological charge densities and
related to it longitudinal part of the correlator of singlet axial currents is
considered in the framework of instanton model. The coupling constant of
eta'-meson with the singlet axial current is determined. Its value appears to
be in a good coincidence with the value determined recently from the connection
of the part of proton spin, carried by u,d,s quarks, with the derivative of QCD
topological susceptibility. From the same sum rule eta-eta' mixing angle is
found in the framework of two mixing angles model. Its value is close to that
found in the chiral effective theory. The correlator of topological charge
densities at large momenta is calculated.


title: B -> Xs l+ l- decays in supersymmetry

abstract:
  We study the semileptonic decays B -> Xs e+ e- and B -> Xs mu+ mu- in generic
supersymmetric extensions of the Standard Model. SUSY effects are parameterized
using the mass insertion approximation formalism and differences with the
Constrained MSSM results are pointed out. Constraints on SUSY contributions
coming from other processes (e.g. b -> s photon) are taken into account.
Chargino and gluino contributions to photon and Z-mediated decays are computed
and non-perturbative corrections are considered. We find that the integrated
branching ratios and the asymmetries can be strongly modified. Moreover, the
behavior of the differential Forward-Backward asymmetry remarkably changes with
respect to the Standard Model expectation.


title: On Metric Preheating

abstract:
  We consider the generation of super-horizon metric fluctuations during an
epoch of preheating in the presence of a scalar field \chi quadratically
coupled to the inflaton. We find that the requirement of efficient broad
resonance is concomitant with a severe damping of super-horizon \delta\chi
quantum fluctuations during inflation. Employing perturbation theory with
backreaction included as spatial averages to second order in the scalar fields
and in the metric, we argue that the usual inflationary prediction for metric
perturbations on scales relevant for structure formation is not strongly
modified.


title:
Baryon Self-Energy With QQQ Bethe-Salpeter Dynamics In The
  Non-Perturbative QCD Regime: n-p Mass Difference

abstract:
  A qqq BSE formalism based on DB{\chi}S of an input 4-fermion Lagrangian of
`current' u,d quarks interacting pairwise via gluon-exchange-propagator in its
{\it non-perturbative} regime, is employed for the calculation of baryon
self-energy via quark-loop integrals. To that end the baryon-qqq vertex
function is derived under Covariant Instantaneity Ansatz (CIA), using Green's
function techniques. This is a 3-body extension of an earlier q{\bar q}
(2-body) result on the exact 3D-4D interconnection for the respective BS wave
functions under 3D kernel support, precalibrated to both q{\bar q} and qqq
spectra plus other observables. The quark loop integrals for the neutron (n) -
proton (p) mass difference receive contributions from : i) the strong SU(2)
effect arising from the d-u mass difference (4 MeV); ii) the e.m. effect of the
respective quark charges. The resultant n-p difference comes dominantly from
d-u effect (+1.71 Mev), which is mildly offset by e.m.effect (-0.44), subject
to gauge corrections. To that end, a general method for QED gauge corrections
to an arbitrary momentum dependent vertex function is outlined, and on on a
proportionate basis from the (two-body) kaon case, the net n-p difference works
out at just above 1 MeV. A critical comparison is given with QCD sum rules
results.


title:
Polarized lepton nucleon scattering -- summary of the theory talks on
  spin physics at DIS 99

abstract:
  We summarize the theory talks given in Working Group 4 `Polarized Lepton
Nucleon Scattering' at the DIS 99 workshop. The significant progress made over
the last year on many of the interesting topics in `spin physics' is
documented.


title: Factorization and Nonfactorization in B Decays

abstract:
  Using NLL values for Wilson coefficients and including the contributions from
the penguin diagrams, we estimate the amount of nonfactorization in two-body
hadronic B decays. Also, we investigate the model dependence of the
nonfactorization parameters by performing the calculation using different
models for the form factors. The results support the universality of
nonfactorizable contributions in both Cabibbo-favored and Cabibbo-suppressed B
decays.


title:
The Soft Gluon Emission Process in the Color-Octet Model for Heavy
  Quarkonium Production

abstract:
  The Color-Octet Model has been used successfully to analyze many problems in
heavy quarkonium production. We examine some of the conceptual and practical
problems of the soft gluon emission process in the Color-Octet Model. We use a
potential model to describe the initial and final states in the soft gluon
emission process, as the emission occurs at a late stage after the production
of the heavy quark pair. It is found in this model that the soft gluon M1
transition, 1S0(8)->3S1(1), dominates over the E1 transition, 3PJ(8)->3S1(1),
for J/psi and psi' production. Such a dominance may help resolve the questions
of isotropic polarization and color-octet matrix element universality in the
Color-Octet Model.


title: Bounds on Flavor Gauge Bosons from Precision Electroweak Data

abstract:
  Gauged flavor symmetries at low energies have been proposed in models of
dynamical electroweak symmetry breaking and fermion mass generation. The
massive flavor gauge bosons give rise to corrections to precisely measured
electroweak quantities. We perform a fit to collider electroweak data and place
indirect limits on such new physics. In particular we study several models from
the literature: universal coloron; chiral top color; chiral, quark family
symmetry; SU(9) and SU(12) chiral, flavor symmetry. The 95% exclusion limits on
the mass of the heavy gauge bosons for these models, at their critical coupling
for chiral symmetry breaking, typically lie between 1-3 TeV. We discuss the
robustness of these bounds with respect to changes in higgs mass, b-quark
asymmetry data, the SLD left right asymmetry data, or additional new physics.


title: Effective Functional Form of Regge Trajectories

abstract:
  We present theoretical arguments and strong phenomenological evidence that
hadronic Regge trajectories are essentially nonlinear and can be well
approximated, for phenomenological purposes, by a specific square-root form.


title: Asymptotic properties of DVCS

abstract:
  We compute the deeply virtual Compton scattering (DVCS) amplitude for forward
and backward scattering in the asymptotic limit. We make use of the Regge
calculus to resum important logarithmic contributions that are beyond those
included by the DGLAP evolution. We find a power-like behavior for the forward
DVCS amplitude.


title: Heavy Quark Production in DIS and Hadron Colliders

abstract:
  We provide a brief overview of some current experimental and theoretical
issues of heavy quark production.


title:
Heavy Thresholds, Slepton Masses and the $\mu$ Term in Anomaly Mediated
  Supersymmetry Breaking

abstract:
  The effects of heavy mass thresholds on anomaly-mediated soft supersymmetry
breaking terms are discussed. While heavy thresholds completely decouple to
lowest order in the supersymmetry breaking, it is argued that they do affect
the breaking terms at higher orders. The relevant contributions typically occur
at lower order in the loop expansion compared to purely anomaly mediated
contributions. The non decoupling contributions may be used to render models in
which the only source of supersymmetry breaking is anomaly mediation viable, by
generating positive contributions to the sleptons' masses squared. They can
also be used to generate acceptable mu- and B-terms.


title: Bimaximal Mixing in an SO(10) Minimal Higgs Model

abstract:
  An SO(10) SUSY GUT model was previously presented based on a minimal set of
Higgs fields. The quark and lepton mass matrices derived fitted the data
extremely well and led to large mixing of muon- and tau-neutrinos in agreement
with the atmospheric neutrino data and to the small-angle MSW solution for the
solar neutrinos. Here we show how a slight modification leading to a non-zero
up quark mass can result in bimaximal mixing for the atmospheric and solar
neutrinos. The "just-so" vacuum solution is slightly favored over the
large-angle MSW solution on the basis of the hierarchy required for the
right-handed Majorana matrix and the more nearly-maximal mixing angles
obtained.


title: The Production of Charginos/Neutralinos and Sleptons at Hadron Colliders

abstract:
  We analyse the production of charginos/neutralinos and sleptons at the hadron
colliders Tevatron and LHC in the direct channels: $p\bar{p}/pp \to
\tilde{\chi}_i \tilde{\chi}_j + X$ and $\tilde{\ell} \bar{\tilde{\ell}'} +X$.
The cross sections for these reactions are given in next-to-leading order SUSY
QCD. By including the higher-order corrections, the predictions become
theoretically stable, being nearly independent of the factorization and
renormalization scales. Since the corrections increase the cross sections, the
discovery range for these particles is extended in the refined analysis.


title: Relating the Quark and Gluon Condensates Through the QCD Vacuum Energy

abstract:
  Using the Cornwall-Jackiw-Tomboulis effective potential for composite
operators we compute the QCD vacuum energy as a function of the dynamical quark
and gluon propagators, which are related to their respective condensates as
predicted by the operator product expansion. The identification of this result
to the vacuum energy obtained from the trace of the energy-momentum tensor
allow us to study the gluon self-energy, verifying that it is fairly
represented in the ultraviolet by the asymptotic behavior predicted by the
operator product expansion, and in the infrared it is frozen at its asymptotic
value at one scale of the order of the dynamical gluon mass. We also discuss
the implications of this identity for heavy and light quarks. For heavy quarks
we recover, through the vacuum energy calculation, the relation $m_{f}
<{\bar{\psi_f}}\psi_f> \sim - {1/12} \gc$ obtained many years ago with QCD sum
rules.


title:
Reanalysis of the Four-Quark Operators Relevant to \Lambda_b Lifetime
  from QCD Sum Rule

abstract:
  \Lambda_b matrix element of four-quark operator relevant to its lifetime is
reanalyzed by QCD sum rule. The new ingredients introduced are that (1) more
vacuum condensates are considered; (2) different quark-hadron duality is
adopted; and (3) the possible deviation from the vacuum saturation assumption
for the four quark condensates is considered. With \kappa_1=4 the related
hadronic parameter r is calculated to be 3.6 \pm 0.9, and the lifetime ratio
\tau(\Lambda_b)/\tau(B^0) = 0.83 \pm 0.04, which is consistent with the
experimental data.


title:
Dynamical Pion Production via Parametric Resonance from Disoriented
  Chiral Condensate

abstract:
  We discuss a dynamical mechanism of pion production from disoriented chiral
condensates (DCC). It leads to an explosive production of pions via the
parametric amplification mechanism, which is similar to the reheating mechanism
in inflationary cosmology. Classically, it is related with the instability in
the solutions of the Mathieu equation and we explore the quantum aspects of the
mechanism. We show that nonlinearlities and back reactions can be ignorable for
sufficiently long time under the small amplitude approximations of background
$\sigma$ oscillations, which may be appropriate for the late stage of
nonequilibrium phase transition. It allows us to obtain an explicit quantum
state of the produced pions and $\sigma$, the squeezed state of BCS type.
Single particle distributions and two-pion correlation functions are computed
within these approximations. The results obtained illuminate the characteristic
features of multi-pion states produced through the parametric amplification
mechanism. In particular, two-pion correlations of various charge combinations
contain back-to-back correlations which cannot be masked by the identical
particle interference effect.


title: Small-x final states and the CCFM equation

abstract:
  The status of the Milan group's work on CCFM-based phenomenology at small x,
and possible directions of future investigation, are discussed.


title: Light Cone Condition for a Thermalized QED Vacuum

abstract:
  Within the QED effective action approach, we study the propagation of
low-frequency light at finite temperature. Starting from a general effective
Lagrangian for slowly varying fields whose structure is solely dictated by
Lorentz covariance and gauge invariance, we derive the light cone condition for
light propagating in a thermalized QED vacuum. As an application, we calculate
the velocity shifts, i.e., refractive indices of the vacuum, induced by
thermalized fermions to one loop. We investigate various temperature domains
and also include a background magnetic field. While low-temperature effects to
one loop are exponentially damped by the electron mass, there exists a maximum
velocity shift of $-\delta v^2_{max}=\alpha/(3\pi)$ in the
intermediate-temperature domain $T\sim m$.


title:
Nonperturbative Power Corrections in $\bar\alpha_s(q^2)$ of Two-Loop
  Analytization Procedure

abstract:
  The analytization procedure which allows one to remove nonphysical
singularities of the QCD running coupling constant $\bar\alpha_s(q^2)$ in the
infrared region is applied to standard as well as to iterative solutions of the
two-loop renormalization group equation. Non-leading at large momentum
nonperturbative contributions in $\bar\alpha_s(q^2)$ are obtained in an
explicit form. The coefficients of nonperturbative contributions expansions in
inverse powers of the squared Euclidean momentum are calculated. For both cases
considered there appear convergent at $q^2>\Lambda^2$ power series of negative
terms with different dependence on term numbers.


title:
Thermodynamics of Deconfined Matter at Finite Chemical Potential in a
  Quasiparticle Description

abstract:
  An effective quasiparticle description of the thermodynamics of deconfined
matter, compatible with both finite-temperature lattice data and the
perturbative limit, is generalized to finite chemical potential. Within this
approach, the available 4-flavor lattice equation of state is extended to
finite baryon density, and implications for cold, charge-neutral deconfined
matter in beta-equilibrium in compact stars are considered.


abstract:
  We present a study of $J/\psi + jet$ diffractive production in the direct
photon process at HERA based on the factorization theorem for lepton-induced
hard diffractive scattering and the factorization formalism of the
nonrelativistic QCD (NRQCD) for quarkonia production. Using the diffractive
gluon distribution function extracted from HERA data on diffractive deep
inelastic scattering and diffractive dijet photon production, we show that this
process can be studied at HERA with present integrated luminosity, and can give
valuable insights in the color-octet mechanism for heavy quarkonia production.


title: CP violation in neutrino mixing matrix and leptogenesis

abstract:
  The CP violation required in leptogenesis may have different origin, but in
an effective theory they all are related to the rephasing invariant CP
violating measure in the mixing matrix of the leptonic sector. We point out
that the maximum amount of CP violation in some models can be estimated with
our present knowledge of the neutrino mixing angles, which can help us
understand the CP violation in the generation of the lepton asymmetry of the
universe. For example, the possibility of leptogenesis may be ruled out in some
models from an knowledge of the effective neutrino mass matrix.


title: An Estimate of Twist-Four Contributions at Small x and Low Q^2

abstract:
  We present a first study of gluonic twist-four corrections to the deep
inelastic structure function F_2 at small x and small Q^2. The calculations are
based upon the double logarithmic approximation of the coupled twist-four
evolution equations of the gluonic twist-four operators that are expected to be
dominant at small x. We first review the analytical results which are presently
available and define the framework of our calculation. In the second part we
discuss the connection with DIS diffractive dissociation which can be used to
estimate the size of some of the twist-four corrections. In the final part we
show, for three different choices of the input distributions, the relative
magnitude of the leading-twist and the twist-four contributions.


title: The AGL Equation from a Dipole Picture

abstract:
  The AGL equation includes all multiple pomeron exchanges in the double
logarithmic approximation (DLA) limit, leading to an unitarized gluon
distribution in the small $x$ regime. This equation was originally obtained
using the Glauber-Mueller approach. We demonstrate in this contribution that
the AGL equation can also be obtained from the dipole picture. Our conclusion
is that the AGL equation is a good candidate for an unitarized evolution
equation at small $x$ in the DLA limit.


title: Neutrino masses and sneutrino mixing in R-parity violating supersymmetry

abstract:
  R-parity-violating supersymmetry with a conserved baryon number B provides a
framework for particle physics with lepton number (L) violating interactions.
Two important probes of the L-violating physics are neutrino masses and
sneutrino-antisneutrino mass-splittings. We evaluate these quantities in the
context of the most general CP-conserving, R-parity-violating B-conserving
extension of the minimal supersymmetric standard model. In generic
three-generation models, three sneutrino-antisneutrino mass splittings are
generated at tree-level. In contrast, only one neutrino mass is generated at
tree-level; the other two neutrinos acquire masses at one-loop. In many models,
the dominant contribution to the radiative neutrino masses is induced by the
non-zero sneutrino-antisneutrino mass splitting.


title:
Detailed study of BBN implications of neutrino oscillation generated
  neutrino asymmetries in some four neutrino models

abstract:
  We re-examine the evolution of neutrino asymmetries in several four neutrino
models. The first case involves the direct creation of $L_{\nu_e}$ by $\nu_e
\leftrightarrow \nu_s$ oscillations. In the second case, we consider the mass
hierarchy $m_{\nu_\tau} \gg m_{\nu_\mu}, m_{\nu_e}, m_{\nu_s}$ where $\nu_\tau
\leftrightarrow \nu_s$ oscillations generate a large $L_{\nu_\tau}$ and some of
this asymmetry is converted into $L_{\nu_e}$ by $\nu_{\tau} \leftrightarrow
\nu_{e}$ oscillations. We estimate the implications for BBN for a range of
cosmologically interesting $\delta m^2$ values. The present paper improves on
previous published work by taking into account the finite repopulation rate and
the time dependence of the distortions to the neutrino momentum distributions.
The treatment of chemical decoupling is also improved.


title:
Lepton-Flavor Violation at Future Lepton Colliders and the Atmospheric
  Neutrino Oscillation

abstract:
  It can be expected from the result for the atmospheric neutrino by the
SUPERKAMIOKANDE and the CHOOZ result that the the lepton-flavor violating (LFV)
interaction between the second and third generations exits at the high energy
scale. This leads to a non-vanishing LFV left-handed slepton mass between the
second and third generations, induced by the radiative correction, in the
minimal supergravity scenario. In this article, assuming that the
supersymmetric standard model with the right-handed neutrinos explains the
atmospheric neutrino result, we show that the reach of the LFV slepton
production in the future lepton colliders can be more significant than that of
tau -> mu gamma.


title:
$F^0-\bar{F}^0 $ Mixing and CP Violation in the General Two Higgs
  Doublet Model

abstract:
  A phenomenological analysis of the general two Higgs doublet model is
presented. Possible constraints of the Yukawa couplings are obtained from the
$K^0-\bar{K}^0, B^0-\bar{B}^0$ and $D^0-\bar{D}^0$ mixings. A much larger
$D^0-\bar{D}^0$ mixing than the standard model prediction is possible. It is
shown that the emerging of various new sources of CP violation in the model
could strongly affect the determination of the unitarity triangle. It can be
helpful to look for a signal of new physics by comparing the extracted angle
$\beta$ from two different ways, such as from the process $B\to J/\psi K_{S}$
and from fitting the quantities $|V_{ub}|, \Delta m_{B}$ and $\epsilon$.


title:
Comment on "Radiative decays, nonet symmetry and SU(3) breaking" by M.
  Benayoun et al

abstract:
  We comment on the paper by Benayoun, DelBuono, Eidelman, Ivanchenko, and
O'Connell [Phys. Rev. {\bf D 59}, 114027 (1999)]. We show that the decay
$\phi\to\pi^0\gamma$ is absent in model of the nonet symmetry and SU(3)
breaking suggested by authors.


title:
Hadronic vacuum polarization contribution to the Lamb shift in muonic
  hydrogen

abstract:
  The contribution of hadronic vacuum polarization to the Lamb shift in muonic
hydrogen is evaluated with the account of modern experimental data on the cross
section of $e^+e^-$ annihilation into hadrons. The numerical value of this
contribution to the (2P-2S) shift in muonic hydrogen is equal to 10.77 $\mu
eV$.


title:
Some thoughts on how to match Leading Log Parton Showers with NLO Matrix
  Elements

abstract:
  We propose a scheme that could offer a convenient Monte Carlo sampling of
next-to-leading-order matrix elements and, at the same time, allow the
interfacing of such parton configurations with a parton-shower approach for the
estimation of higher-order effects. No actual implementation exists so far, so
this note should only be viewed as the outline of a possible road for the
future, submitted for discussion.


title:
Next-to-Leading Order QCD corrections to the Lifetime Difference of
  $B_s$ Mesons

abstract:
  In this talk we present a calculation of the dacay rate difference in the
neutral $B_s-\bar{B}_s$ system, $\Delta \Gamma_{B_s}$, in next-to-leading order
(NLO) QCD. We find a sizeable decrease compared to leading-order (LO)
estimates: $ (\Delta \Gamma/\Gamma)_{B_s} = (f_{B_s}/210 MeV)^2 [0.006 B(m_b) +
0.150 B_S(m_b) - 0.0063]$ in terms of the bag parameters $B$ and $B_S$ in the
NDR scheme. We put special emphasize on the theoretical and physical
implications of this quantity.


title: Rotating QCD string and the meson spectrum

abstract:
  The spectra of light-light and heavy-light mesons are described by spinless
Salpeter equation and Dirac equation respectively, which predict linear
dependence of the meson mass squared M^2 on angular momentum J and number of
radial nodes n. Both spectra are computed by the WKB method and shown to agree
with exact numerical data within few percent even for the lowest levels. The
drawback of Salpeter and Dirac equation is that (inverse) Regge slopes do not
coincide with the string ones, 2\pi\sigma and \pi\sigma respectively, because
the string dynamics is not taken into account properly. The lacking string
rotation is introduced via effective Hamiltonian derived from QCD which
generates linear Regge trajectories for light mesons with the correct string
slope.


title:
Logarithmic expansion of electroweak corrections to four-fermion
  processes in the TeV region

abstract:
  Starting from a theoretical representation of the electroweak component of
four-fermion neutral current processes that uses as theoretical input the
experimental measurements at the Z peak, we consider the asymptotic high energy
behaviour in the Standard Model at one loop of those gauge-invariant
combinations of self-energies, vertices and boxes that contribute all the
different observables. We find that the logarithmic contribution due to the
renormalization group running of the various couplings is numerically
overwhelmed by single and double logarithmic terms of purely electroweak
(Sudakov-type) origin, whose separate relative effects grow with energy,
reaching the 10% size at about one TeV. We then propose a simple "effective"
parametrization that aims at describing the various observables in the TeV
region, and discuss its validity both beyond and below 1 TeV, in particular in
the expected energy range of future linear electron-positron (LC) and muon-muon
colliders.


title: Higher-twist corrections to nucleon structure functions from lattice QCD

abstract:
  A genuinely non-perturbative evaluation of higher-twist contributions to the
structure functions of the nucleon, with all mixing effects and renormalon
ambiguities taken care of, is presented. Higher-twist corrections turn out to
be significant at moderate values of $q^2$.


title: Nucleon Spin with and without Hyperon Data: A New Tool for Analysis

abstract:
  We present a simple explanation of the underlying physics in the use of
hyperon decay data to obtain information about proton spin structure. We also
present an alternative input using nucleon magnetic moment data and show that
the results from the two approaches are nearly identical. The role of symmetry
breaking is clarified while pointing out that simple models explaining the
violation of the Gottfried sum rule via pion emission tend to lose the good
SU(3) predictions from Cabibbo theory for hyperon decays.


title:
Toward Equilibration in the Early Stages After a High Energy Heavy Ion
  Collision

abstract:
  The early stages in the evolution of the gluons produced in the central
region of a head-on high-energy heavy ion collision is studied. An equation is
given for the rate of change of transverse momentum into longitudinal momentum
where the longitudinal direction is along the collision axis. We are able to
follow the system up to the time where equilibration seems to be setting in,
but we are unable to actually follow the system as it reaches equilibrium.


title: Running Coupling BFKL Equation and Deep Inelastic Scattering

abstract:
  I examine the form of the solution of the BFKL equation with running coupling
relevant for deep inelastic scattering. The evolution of structure functions is
precisely determined and well described by an effective coupling of the form
1/(beta_0(ln(Q^2/Lambda^2)+3.6(alpha_s(Q^2)ln(1/x))^1/2)) (until very small x).
Corrections to the LO equation are relatively small, and the perturbative
expansion is stable. Comparison to data via a global fit is very successful.


title:
The Two-Loop Scale Dependence of the Static QCD Potential including
  Quark Masses

abstract:
  The interaction potential V(Q^2) between static test charges can be used to
define an effective charge $\alpha_V(Q^2)$ and a physically-based
renormalization scheme for quantum chromodynamics and other gauge theories. In
this paper we use recent results for the finite-mass fermionic corrections to
the heavy-quark potential at two-loops to derive the next-to-leading order term
for the Gell Mann-Low function of the V-scheme. The resulting effective number
of flavors $N_F(Q^2/m^2)$ in the $\alpha_V$ scheme is determined as a
gauge-independent and analytic function of the ratio of the momentum transfer
to the quark pole mass. The results give automatic decoupling of heavy quarks
and are independent of the renormalization procedure. Commensurate scale
relations then provide the next-to-leading order connection between all
perturbatively calculable observables to the analytic and gauge-invariant
$\alpha_V$ scheme without any scale ambiguity and a well defined number of
active flavors. The inclusion of the finite quark mass effects in the running
of the coupling is compared with the standard treatment of finite quark mass
effects in the $\bar{MS}$ scheme.


title: Photon emission in Pb+Pb collisions at SpS and LHC

abstract:
  Yield of direct photons in Pb+Pb collisions at SpS and LHC energy is
evaluated with emphasis on estimate of possible uncertainty. Possibility of
experimental observation of direct photons at LHC is discussed. Predictions of
several models at SpS energy are compared with experimental data.


title: Top and gluons at lepton colliders

abstract:
  In this talk we present results of an exact calculation of gluon radiation in
top production and decay at lepton colliders, including all spin correlations
and interferences. We compare properties of gluons radiated in the production
and decay stages and investigate the sensitivity of interference effects to the
top decay width.


title:
Gauge Coupling Unification with Extra Dimensions and Gravitational Scale
  Effects

abstract:
  We study gauge coupling unification in the presence of extra dimensions
compactified at a few TeV. Achieving unification requires a large number of
gauge boson Kaluza-Klein excitations lighter than the string scale, such that
the higher-dimensional gauge couplings are O(1) in string scale units.
Corrections to the gauge couplings from two or more loops are about 10% or
larger, hence string (or M) theory is generally expected to be strongly coupled
in TeV-scale extra-dimensional scenarios. Higher-dimensional operators induced
by quantum gravitational effects can shift the gauge couplings by a few
percent. These effects are sufficiently large that even the minimal Standard
Model, or the MSSM, allow unification at a scale in the TeV range. The strongly
coupled unified theory may induce dynamical electroweak symmetry breaking.


title:
Probing Neutrino Magnetic Moments at Underground Detectors with
  Artificial Neutrino Sources

abstract:
  Neutrino-electron scattering can be used to probe neutrino electromagnetic
properties at low-threshold underground detectors with good angular and recoil
electron energy resolution. We propose to do this using a number of artificial
neutrino and anti-neutrino sources such as $^{51}Cr_{24}$ and $^{90}Sr-Y$. The
neutrino flux is known to within one percent, in contrast to the reactor case
and one can reach lower neutrino energies. For the $^{90}Sr-Y$ source we
estimate that the signal expected for a neutrino magnetic moment of
$\mu_{\nu}=6 \times 10^{-11}\mu_{B}$ will be comparable to that expected in the
SM and corresponds to a 30% enhancement in the total number of expected events.


title: Anomalous Couplings of the Third Generation in Rare B Decays

abstract:
  We study the potential effect of anomalous couplings of the third generation
quarks to gauge bosons in rare B decays. We focus on the constraints from
flavor changing neutral current processes such as $b\to s\gamma$ and $b\to s
\ell^+\ell^-$. We consider both dimension-four and dimension-five operators and
show that the latter can give large deviations from the standard model in the
still unobserved dilepton modes, even after the bounds from $b\to s\gamma$ and
precision electroweak observables are taken into account.


title: FCNC and non-standard soft-breaking terms in weak-scale Supersymmetry

abstract:
  We study the inclusion of non-standard soft-breaking terms in the minimal
SUSY extension of the SM, considering it as a model of weak-scale SUSY. These
terms modify the sfermion mass matrices, which can induce new sources of
flavour violation. Bounds on the new soft parameters can be estimated from
current data. The results are then applied to evaluate FCNC top decay t -> c +
hi (hi= h,H,A). Implications of complex soft parameters for CP violation are
also addressed.


title: Assisted Chaotic Inflation in Higher Dimensional Theories

abstract:
  We address the problem of the large initial field values in chaotic inflation
and propose a remedy in the framework of the so-called assisted inflation. We
demonstrate that a 4-dimensional theory of multiple, scalar fields with initial
field values considerably below the Planck scale, can give rise to inflation
even though none of the individual scalar fields are capable of driving
inflation. The problems arising from the presence of possible
non-renormalizable interactions is therefore removed. As a concrete example of
a theory with multiple scalar fields, we consider a (4+d)-dimensional field
theory of a single, non-interacting massive scalar field whose KK modes play
the role of the assisted sector. For the KK modes to assist inflation, the
extra dimensions must have a size larger than the inverse (4D) Planck scale.


title:
Radiative corrections to the Z b b-bar vertex and constraints on
  extended Higgs sectors

abstract:
  We explore the radiative corrections to the process Z --> b b-bar in models
with extended Higgs sectors. The observables R_b (the Z hadronic branching
fraction to b b-bar) and the b-quark asymmetry A_b = (g_L^2 - g_R^2)/(g_L^2 +
g_R^2) are sensitive to these corrections. We find that in models containing
only Higgs doublets, singlets, or larger multiplets constrained by a custodial
SU(2) symmetry, the radiative corrections to R_b involving charged Higgs bosons
always worsen the Standard Model fit to electroweak data. Thus, the present R_b
data can be used to set lower bounds on the charged Higgs masses in such
models. Radiative corrections to R_b involving light neutral Higgs bosons in
models with enhanced couplings to b b-bar can improve the Standard Model fit to
present data. The Higgs sector alone cannot explain a significant deviation of
A_b from its Standard Model prediction. We present general formulas for the
corrections to R_b and A_b in an SU(2)xU(1) electroweak model with an arbitrary
extended Higgs sector, and derive explicit results for a number of specific
models.


title:
Precision Tests in e+e- and gamma-gamma processes and Virtual New
  Physics Effects

abstract:
  Contribution to LP99, International Symposium on Lepton-Photon Interactions,
Stanford, Aug.1999. Summary of works done in collaboration with M. Beccaria, P.
Ciafaloni, D. Comelli, G.J. Gounaris, J. Layssac, P. Porfyriadis, S. Spagnolo,
C. Verzegnassi. We report on several works dealing with precison tests of the
Standard Model (SM) and beyond, in the processes $e^+e^-\to f\bar f$ (f= lepton
or quarks) and $\gamma\gamma \to \gamma\gamma, \gamma Z$. We first point out a
set of remarkable properties of the SM amplitudes and observables at high
energies, at tree level and at 1-loop, like "Sudakov" behaviour or the
dominance of purely imaginary non-flip amplitudes due to the WWWW box. We then
consider various types of virtual NP contributions due to supersymmetry,
anomalous gauge boson couplings, technicolour and extended gauge structures.
Effects at LEP2 and LC (in particular with a laser backscattering
$\gamma\gamma$ mode) are discussed. We point out specific features like clear
threshold enhancements.


title:
Hadronic returns to the Z in electron-positron annihilation at high
  energy

abstract:
  The production of four hadronic jets in e+e- collisions above the Z pole is
dominated by the QCD e+e- --> qqqq,qqgg processes and, for sufficiently high
energy, the electroweak e+e- --> W+W- --> qqqq process. However there is
another mechanism for producing four jets, e+e- --> Z gg --> qqgg, which can be
regarded as a `hadronic return' to the Z pole. We investigate this new process
in detail


title: Models of Neutrino Masses and Baryogenesis

abstract:
  Majorana masses of the neutrino implies lepton number violation and is
intimately related to the lepton asymmetry of the universe, which gets related
to the baryon asymmetry of the universe in the presence of the sphalerons
during the electroweak phase transition. Assuming that the baryon asymmetry of
the universe is generated before the electroweak phase transition, it is
possible to dicriminate different classes of models of neutrino masses. While
see-saw mechanism and the triplet higgs mechanism are preferred, the Zee-type
radiative models and the R-parity breaking models requires additional inputs to
generate baryon asymmetry of the universe during the electroweak phase
transition.


title: Finding CP-violating Higgses

abstract:
  In a general two-Higgs-doublet model with CP violation in the Higgs sector,
the three neutral physical Higgs bosons have no definite CP properties. A new
sum rule relating Yukawa and Higgs-Z couplings implies that a neutral Higgs
boson cannot escape detection at an e^+e^- collider if it is kinematically
accessible in Z+Higgs, $b\bar b+$Higgs and $t\bar t+$Higgs production,
irrespective of the mixing angles and the masses of the other neutral Higgs
bosons. The implications of the sum rules for Higgs discovery at the Tevatron
and LHC are briefly mentioned.


title: Structure function evolution at next-to-leading order and beyond

abstract:
  Results are presented of two studies addressing the scaling violations of
deep-inelastic structure functions. Factorization-scheme independent fits to
all ep and mu p data on F_2 are performed at next-to-leading order (NLO),
yielding alpha_s(M_Z) = 0.114 +- 0.002_exp (+0.006-0.004)_th . In order to
reduce the theoretical error dominated by the renormalization-scale dependence,
the next-higher order (NNLO) needs to be included. For the flavour non-singlet
sector, it is shown that available calculations provide sufficient information
for this purpose at x > 10^-2.


title: Resummation for Heavy Quark Production Near Partonic Threshold

abstract:
  We review some techniques of resummation applied to heavy quark production in
hadronic scattering and electroproduction near partonic threshold, and discuss
the reduction of factorization scale dependence in resummed cross sections.


title:
Conformal Symmetry as a Template: Commensurate Scale Relations and
  Physics Renormalization Schemes

abstract:
  Commensurate scale relations are perturbative QCD predictions which relate
observable to observable at fixed relative scale, such as the "generalized
Crewther relation", which connects the Bjorken and Gross-Llewellyn Smith deep
inelastic scattering sum rules to measurements of the e+ e- annihilation cross
section. We show how conformal symmetry provides a template for such QCD
predictions, providing relations between observables which are present even in
theories which are not scale invariant. All non-conformal effects are absorbed
by fixing the ratio of the respective momentum transfer and energy scales. In
the case of fixed-point theories, commensurate scale relations relate both the
ratio of couplings and the ratio of scales as the fixed point is approached. In
the case of the $\alpha_V$ scheme defined from heavy quark interactions,
virtual corrections due to fermion pairs are analytically incorporated into the
Gell-Mann Low function, thus avoiding the problem of explicitly computing and
resumming quark mass corrections related to the running of the coupling.
Applications to the decay width of the Z boson, the BFKL pomeron, and virtual
photon scattering are discussed.


title: The entropy of the QCD plasma

abstract:
  Self-consistent approximations in terms of fully dressed propagators provide
a simple expression for the entropy of an ultrarelativistic plasma, which
isolates the contribution of the elementary excitations as a leading
contribution. Further approximations, whose validity is checked on a soluble
model involving a scalar field, allow us to calculate the entropy of the QCD
plasma. We obtain an accurate description of lattice data for purely gluonic
QCD, down to temperatures of about twice the transition temperature.


title: Phenomenology of flavor-mediated supersymmetry breaking

abstract:
  The phenomenology of a new economical SUSY model that utilizes dynamical SUSY
breaking and gauge-mediation (GM) for the generation of the sparticle spectrum
and the hierarchy of fermion masses is discussed. Similarities between the
communication of SUSY breaking through a messenger sector, and the generation
of flavor using the Froggatt-Nielsen (FN) mechanism are exploited, leading to
the identification of vector-like messenger fields with FN fields, and the
messenger U(1) as a flavor symmetry. An immediate consequence is that the first
and second generation scalars acquire flavor-dependent masses, but do not
violate FCNC bounds since their mass scale, consistent with effective SUSY, is
of order 10 TeV. We define and advocate a minimal flavor-mediated model (MFMM),
recently introduced in the literature, that successfully accommodates the small
flavor-breaking parameters of the standard model using order one couplings and
ratios of flavon field vevs. The mediation of SUSY breaking occurs via two-loop
log-enhanced GM contributions, as well as several one-loop and two-loop
Yukawa-mediated contributions for which we provide analytical expressions. The
MFMM is parameterized by a small set of masses and couplings, with values
restricted by several model constraints and experimental data. The
next-to-lightest sparticle (NLSP) always has a decay length that is larger than
the scale of a detector, and is either the lightest stau or the lightest
neutralino. Similar to ordinary GM models, the best collider search strategies
are, respectively, inclusive production of at least one highly ionizing track,
or events with many taus plus missing energy. In addition, D^0 - \bar{D}^0
mixing is also a generic low energy signal. Finally, the dynamical generation
of the neutrino masses is briefly discussed.


title:
The Higgs Boson Mass in Gauge-Mediated Supersymmetry-Breaking Models
  with Generalized Messenger Sectors

abstract:
  The lighter neutral scalar Higgs mass is examined in gauge-mediated
supersymmetry-breaking models in which the messenger sector responsible for
SUSY breaking is allowed to involve more general sets of $SU(3) \otimes SU(2)
\otimes U(1)$ multiplets than those contained in the SU(5) $5 + \bar{5}$ or $10
+ \bar{10}$ multiplets. The largest mass for the lighter scalar Higgs is found
to be 132 GeV when the breaking parameter $\Lambda$ is taken to be 100 TeV\@.
Thus the predictions for the lightest Higgs mass can be tested at the upgraded
Tevatron runs for these general classes of GMSB models.


title:
Unification of gauge couplings and the tau neutrino mass in Supergravity
  without R-parity

abstract:
  Minimal R-parity violating supergravity predicts a value for $alpha_s(M_Z)$
smaller than in the case with conserved R-parity, and therefore closer to the
experimental world average. We show that the R-parity violating effect on the
$alpha_s$ prediction comes from the larger two-loop b-quark Yukawa contribution
to the renormalization group evolution of the gauge couplings which
characterizes R-parity violating supergravity. The effect is correlated to the
tau neutrino mass and is sensitive to the initial conditions on the soft
supersymmetry breaking parameters at the unification scale. We show how a few
percent effect on $alpha_s(M_Z)$ may naturally occur even with tau neutrino
masses as small as indicated by the simplest neutrino oscillation
interpretation of the atmospheric neutrino data from Super-Kamiokande.


title: Signatures of HyperCharge Axions in Colliders

abstract:
  If in addition to the standard model fields, a new pseudoscalar field that
couples to hypercharge topological number density, the hypercharge axion,
exists, it can be produced in colliders in association with photons or Z
bosons, and detected by looking for its decay into photons or Z's. For a range
of masses below a TeV and coupling above a fraction of 1/TeV, existing data
from LEP II and the Tevatron can already put interesting constraints, and in
future colliders accessible detection range is increased significantly. The
hypercharge axion can help in explaining the matter-antimatter asymmetry in the
universe.


title:
Probing the Desert with Ultra--Energetic Neutrinos from the Sun and the
  Earth

abstract:
  Realistic superstring models generically give rise to exotic matter states,
which arise due to the ``Wilson-line'' breaking of the non-Abelian unifying
gauge symmetry. Often such states are protected by a gauge or local discrete
symmetry and therefore may be stable or meta-stable. We study the possibility
of a flux of high energy neutrinos coming from the sun and the earth due to the
annihilation of such exotic string states. We also discuss the expected flux
for other heavy stable particles -- like the gluino LSP. We comment that the
detection of ultra-energetic neutrinos from the sun and the earth imposes model
independent constraints on the high energy cutoff, as for example in the
recently entertained TeV scale Kaluza-Klein theories. We therefore propose that
improved experimental resolution of the energy of the muons in neutrino
detectors together with their correlation with neutrinos from the sun and the
center of the earth will serve as a probe of the desert in Gravity Unified
Theories.


title: On two-color QCD with baryon chemical potential

abstract:
  We study SU(2) color QCD with even number of quark flavors. First, using QCD
inequalities we show that at finite baryon chemical potential mu, condensation
must occur in the channel with scalar diquark quantum numbers. This breaks the
U(1) symmetry generated by baryon charge (baryon superconductivity). Then we
derive the effective Lagrangian describing low lying meson and baryon
excitations using extended local chiral symmetry of the theory. This enables us
to determine the leading term in the dependence of the masses on mu exactly.


title: On a possible EPR experiment with $B^{0}_{d}\bar{B^{0}_{d}}$ pairs

abstract:
  A very general local realistic theory of single $B^{0}_{d}$ mesons and of
correlated $B^{0}_{d}\bar{B^{0}_{d}}$ pairs is formulated. If these pairs are
produced in the $\Upsilon (4S)$ decay, the local realistic asymmetry for
observing pairs with like and unlike flavour at different proper times
remarkably differs from the quantum mechanical prediction. Asymmetric
B-factories provide a powerful tool for the study of the EPR problem since the
relative detection experiments are shown to be capable of a time-dependent
measurement precise enough to discriminate between local realism and quantum
theory.


title:
The Cosmological Constant as a Residual Energy in the Chaotic
  Inflationary Model

abstract:
  A new idea of the cosmological constant is proposed in this paper. Due to the
horizon is limited, the quantum fluctuation of the inflaton field is not zero,
a nonzero vacuum energy is remained as a residual inflationary energy of an
unusual potential, however the true stable vacuum energy is zero fortunately. A
unified model of the cosmological constant and the chaotic inflation is
proposed, which satisfies almost all cosmological phenomenology and will can be
tested by data of the cosmic large scale structure.