title:
Electroweak symmetry breaking in Higgs mechanism with composite
  operators and solution of naturalness

abstract:
  Introducing a source for a bi-local composite operator motivated by the
perturbative expansion in gauge couplings, we calculate its effective potential
in the renormalization group of Standard Model with no involvement of
technicolor. The potential indicates the breaking of electroweak symmetry below
a scale M due to a nonzero vacuum expectation value of neutral component for
the SU(2)-doublet operator. At virtualities below a cut off \Lambda we
introduce the local higgs approximation for the effective fields of sources
coupled to the composite operators. The value of \Lambda\approx 600 GeV is
fixed by the measured masses of gauge vector bosons. The exploration of
equations for infrared fixed points of calculated Yukawa constants allows us to
evaluate the masses of heaviest fermion generation with a good accuracy, so
that m_t(m_t) = 165\pm 4 GeV, m_b(m_b) = 4.18\pm 0.38 GeV and m_\tau(m_\tau) =
1.78\pm 0.27 GeV. After a finite renormalization of effective fields for the
sources of composite operators, the parameters of effective Higgs field
potential are calculated at the scale of matching with the local theory
\Lambda. The fixed point for the Yukawa constant of t quark and the matching
condition for the null effective potential at M drive the M value to the GUT
scale. The equation for the infrared fixed point of quartic self-action allows
us to get estimates for two almost degenerate scalar particles with m_H= 306\pm
5 GeV, while third scalar coupled with the tau lepton is more heavy: m_{H_\tau}
= 552\pm 9 GeV. Some phenomenological implications of the offered approach
describing the effective scalar field, and a problem on three fermion
generations are discussed.


title:
Light Lepton Number Violating Sneutrinos and the Baryon Number of the
  Universe

abstract:
  Recent results of neutrino oscillation experiments point to a nonvanishing
neutrino mass. Neutrino mass models favour Majorana-type neutrinos. In such
circumstances it is natural that the supersymmetric counterpart of the
neutrino, the sneutrino, bears also lepton number violating properties. On the
other hand, the fact that the universe exhibits an asymmetry in the baryon and
antibaryon numbers poses constraints on the extent of lepton number violation
in the light sneutrino sector if the electroweak phase transition is second or
weak first order. From the requirement that the Baryon Asymmetry of the
Universe should not be washed out by sneutrino induced lepton number violating
interactions and sphalerons below the critical temperature of the electroweak
phase transition we find that the mass splitting of the light sneutrino mass
states is compatible with the sneutrino Cold Dark Matter hypothesis only for
heavy gauginos and opposite sign gaugino mass parameters.


title:
Bloom-Gilman duality of the nucleon structure function and the elastic
  peak contribution

abstract:
  The occurrence of the Bloom-Gilman duality in the nucleon structure function
is investigated by analyzing the Q**2-behavior of low-order moments, both
including and excluding the contribution arising from the nucleon elastic peak.
The Natchmann definition of the moments has been adopted in order to cancel out
target-mass effects. It is shown that the onset of the Bloom-Gilman duality
occurs around Q**2 ~ 2 (GeV/c)**2 if only the inelastic part of the nucleon
structure function is considered, whereas the inclusion of the nucleon elastic
peak contribution leads to remarkable violations of the Bloom-Gilman duality.


title:
Free Energy of an SU(2) Model of (2+1)-dimensional QCD in the Constant
  Condensate Background

abstract:
  Gluon and quark contributions to the thermodynamic potential (free energy) of
a (2+1)-dimensional QCD model at finite temperature in the background of a
constant homogeneous chromomagnetic field H combined with A_0 condensate are
calculated. The role of the tachyonic mode in the gluon energy spectrum is
discussed. A possibility of the free energy global minimum generation at
nonzero values of H and A_0 condensates is investigated.


title:
Polarization and Spin Effects in Neutralino Production and Decay in
  Supersymmetric Models

abstract:
  We study polarization and spin correlation effects in the MSSM and in
extended supersymmetric models at an e^+e^- linear collider with polarized
beams. The production of light neutralinos e^+ e^- --> \tilde\chi^0_1
\tilde\chi^0_2 and the subsequent decay \tilde\chi^0_2 --> \tilde\chi^0_1 e^+
e^- including full spin correlations is compared in three supersymmetric
models: MSSM, NMSSM and an E_6-inspired model with an additional U(1)' gauge
group. It is shown that polarization and spin effects can lead to a complete
different behavior of these models. Finally, the dependence of the cross
section and the decay angular distribution on the gaugino mass parameter M_1
for polarized beams is briefly outlined.


title:
Can Baryogenesis Survive in the Standard Model Due To Strong
  Hypermagnetic Field?

abstract:
  The electroweak phase transition in a constant hypermagnetic field=A0 is
studied in the Standard Model. The symmetry behaviour is investigated within
the consistent effective potential of the scalar and magnetic fields at finite
temperature. It includes the one-loop and ring diagram contributions. All
fundamental fermions and bosons are taken into consideration with their actual
masses. The only free parameter is the Higgs boson mass which is chosen to be
in the energy interval 75 GeV $\le m_H \le$=A0 115 GeV.=A0 It is found that for
the field strengths $H \sim 10^{22}- 10^{23}$G the electroweak phase transition
is of first order but a baryogenesis condition is not satisfied. For stronger
fields it=A0 becomes of second order. Hence it is concluded that the smooth
hypermagnetic field does not generate the strong first order phase transition
and the baryogenesis does not survive in the Standard Model. The comparison
with the results of other approaches is done.


title: Magnetic screening in the hot gluon system

abstract:
  The gluon transverse self-energy of the pure Yang-Mills system at
high-temperature is analysed in the static limit and at fourth order in the
coupling. Possible contributions to this function are collected, seen to be
gauge-fixing independent subsets and shown to vanish all, except those which
are either regulators or constituents of the self-energy of Euklidean 3D
Yang-Mills theory at zero temperature. The latter self-energy, in turn, is
known from the non-perturbative analysis by Karabali and Nair.


title:
Static Potential in the SU(2)-Higgs Model and the Electroweak Phase
  Transition

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: Strange Form Factors of Octet and Decuplet Baryons

abstract:
  The strange form factors of baryon octet are evaluated, in the chiral models
with the general chiral SU(3) group structure, to yield the theoretical
predictions comparable to the recent experimental data of SAMPLE Collaboration
and to study the spin symmetries. Other model predictions are also briefly
reviewed to compare with our results and then the strange form factors of
baryon octet and decuplet are predicted.


title: Signals for CPT and Lorentz Violation in Neutral-Meson Oscillations

abstract:
  Experimental signals for indirect CPT violation in the neutral-meson systems
are studied in the context of a general CPT- and Lorentz-violating
standard-model extension. In this explicit theory, some CPT observables depend
on the meson momentum and exhibit diurnal variations. The consequences for CPT
tests vary significantly with the specific experimental scenario. The wide
range of possible effects is illustrated for two types of CPT experiment
presently underway, one involving boosted uncorrelated kaons and the other
involving unboosted correlated kaon pairs.


title: On Effective Theory of Brane World with Small Tension

abstract:
  The five dimensional theory compactified on $S^1$ with two ``branes'' (two
domain walls) embedded in it is constructed, based on the field-theoretic
mechanism to generate the ``brane''. Some light states localized in the
``brane'' appear in the theory. One is the Nambu-Goldstone boson, which
corresponds to the breaking of the translational invariance in the transverse
direction of the ``brane''. In addition, if the tension of the ``brane'' is
smaller than the fundamental scale of the original theory, it is found that
there may exist not only massless states but also some massive states lighter
than the fundamental scale in the ``brane''. We analyze the four dimensional
effective theory by integrating out the freedom of the fifth dimension. We show
that some effective couplings can be explicitly calculated. As one of our
results, some effective couplings of the state localized in the ``brane'' to
the higher Kaluza-Klein modes in the bulk are found to be suppressed by the
width of the ``brane''. The resultant suppression factor can be quantitatively
different from the one analyzed by Bando et al. using the Nambu-Goto action,
while they are qualitatively the same.


title:
Resonances, Chiral Symmetry, Coupled Channel Unitarity and Effective
  Lagrangians

abstract:
  By means of a coupled channel non-perturbative unitary approach, it is
possible to extend the strong constrains of Chiral Perturbation Theory to
higher energies. In particular, it is possible to reproduce the lowest lying
resonances in meson-meson scattering up to 1.2 GeV using the parameters of the
O(p^2) and O(p^4) Chiral Lagrangian. We report on an update of these results
examining their possible relevance for meson spectroscopy.


title:
Nuclear-Medium Modification of the Rho(1S)- and Rhoprim(2S)-Mesons in
  Coherent Photo- and Electroproduction: Coupled Channel Analysis

abstract:
  We study medium modifications of the dilepton mass spectrum in coherent
photo- and electroproduction of the Rho(1S)- and Rhoprim(2S)-meson resonances
on nuclear targets. The analysis is performed within the coupled Rho,
Rhoprim... channel formalism in which nuclear modifications derive from the
off-diagonal rescatterings. We find that the effect of off-diagonal
rescatterings on the shape of the dilepton mass spectrum in the Rho(1S)-meson
mass region is only marginal but is very important in the Rhoprim mass region.
The main off-diagonal contribution in the Rhoprim mass region comes from the
sequential mechanism gamma* -> Rho -> Rhoprim(2S), which dominates the
Rhoprim(2S) production for heavy nuclei.
  Our results show also that in the Rhoprim(2S) mass region there is a
considerable effect of the interference of the Breit-Wigner tail of
Rho(1S)-meson with the Rhoprim-meson.


title:
Astrophysical Implications of the Induced Neutrino Magnetic Moment from
  Large Extra Dimensions

abstract:
  Theories involving extra dimensions, a low (TeV) string scale and bulk
singlet neutrinos will produce an effective neutrino magnetic moment which may
be large (< 10^{-11} mu_B). The effective magnetic moment increases with
neutrino energy, and therefore high energy reactions are most useful for
limiting the allowed number of extra dimensions. We examine constraints from
both neutrino-electron scattering and also astrophysical environments. We find
that supernova energy loss considerations require a number of extra dimensions,
n > 1, for an electron neutrino-bulk neutrino Yukawa coupling of order 1.


title: Tau Decay Determination of the Strange Quark Mass

abstract:
  The recent ALEPH measurements of the inclusive Cabibbo--suppressed decay
width of the $\tau$ and several moments of its invariant mass distribution are
used to determine the value of the strange quark mass. We obtain, in the
$\bar{\rm MS}$ scheme, $m_s(M_\tau^2) = (119\pm 24)$ MeV, which corresponds to
$ m_s(1 {\rm GeV}^2) = (164 \pm 33) {\rm MeV}, m_s(4 {\rm GeV}^2) = (114\pm 23)
{\rm MeV} $.


title: B-Decay CP Asymmetries, Discrete Ambiguities and New Physics

abstract:
  The first measurements of CP violation in the $B$ system will likely probe
$\sin 2\alpha$, $\sin 2\beta$ and $\cos 2\gamma$. Assuming that the CP angles
$\alpha$, $\beta$ and $\gamma$ are the interior angles of the unitarity
triangle, these measurements determine the angle set $(\alpha,\beta,\gamma)$
except for a twofold discrete ambiguity. If one allows for the possibility of
new physics, the presence of this discrete ambiguity can make its discovery
difficult: if only one of the two candidate solutions is consistent with
constraints from other measurements in the $B$ and $K$ systems, one is not sure
whether new physics is present or not. We review the methods used to resolve
the discrete ambiguity and show that, even in the presence of new physics, they
can usually be used to uncover this new physics. There are some exceptions,
which we describe in detail. We systematically scan the parameter space and
present examples of values of $(\alpha,\beta,\gamma)$ and the new-physics
parameters which correspond to all possibilities. Finally, we show that if one
relaxes the assumption that the bag parameters $\BBd$ and $\BK$ are positive,
one can no longer definitively establish the presence of new physics.


title: Exploring CP Violation with B_d -> D K_s Decays

abstract:
  We (re)examine CP violation in the decays B_d -> D K_s, where D represents
D^0, D(bar), or one of their excited states. The quantity $\sin^2(2\beta +
\gamma)$ can be extracted from the time-dependent rates for $B_d(t) -> {\bar
D}^{**0} K_s$ and $B_d(t) -> D^{**0} K_s$, where the $D^{**0}$ decays to
$D^{(*)+}\pi^-$. If one considers a non-CP-eigenstate hadronic final state to
which both D(bar) and D^0 can decay (e.g. $K^+\pi^-$), then one can obtain two
of the angles of the unitarity triangle from measurements of the time-dependent
rates for $B_d(t) -> (K^+\pi^-)_{D K_s}$ and $B_d(t) -> (K^-\pi^+)_{D K_s}$.
There are no penguin contributions to these decays, so all measurements are
theoretically clean.


title: CP Violation in Hyperon Decays from Supersymmetry

abstract:
  It was pointed out recently that supersymmetry can generate flavor-changing
gluonic dipole operators with sufficiently large coefficients to dominate the
observed value of epsilon'/epsilon. We point out that the same operators
contribute to direct CP violation in hyperon decay and can generate a CP
violating asymmetry A(\Lambda^0_-) in the range probed by the current E871
experiment. Interestingly, models that naturally reproduce the relation lambda
= sqrt{m_d/m_s} do not generate epsilon'/epsilon but could lead to an
A(\Lambda^0_-) of O(10^{-3}).


title: Constraints on Hidden Sector Gaugino Condensation

abstract:
  We study the phenomenology of a class of models describing modular invariant
gaugino condensation in the hidden sector of a low-energy effective theory
derived from the heterotic string. Placing simple demands on the resulting
observable sector, such as a supersymmetry-breaking scale of approximately 1
TeV, a vacuum with properly broken electroweak symmetry, superpartner masses
above current direct search limits, etc., results in significant restrictions
on the possible configurations of the hidden sector.


title: Model-independent information on gamma from B^+- -> pi K Decays

abstract:
  Measurements of the rates for the hadronic decays B^+- -> pi K can be used to
derive information on the weak phase gamma=arg(V_ub^*) in a largely
model-independent way. Hadronic uncertainties can be reduced to the level of
nonfactorizable contributions to the decay amplitudes that are power-suppressed
in Lambda/m_b and, in addition, either violate SU(3) flavor symmetry or are
doubly Cabibbo suppressed. Various strategies to obtain bounds on gamma and to
extract its value with small theoretical uncertainty are described. The
potential of B^+- -> pi K decays for probing physics beyond the Standard Model
is also discussed.


title: alpha_s^3 conversion relation betweeen MS-bar and Euclidean quark masses

abstract:
  We report on the analytical calculation of NNNLO (of order alpha_s^3)
conversion factor between the MS-bar quark mass and the one defined in the
so-called Regularization Invariant scheme. The NNNLO contribution in the
conversion factor turns out to be relatively large and comparable to the known
NNLO term.


title: Direct CP violation in B decays in R-parity violating models

abstract:
  In the standard model, CP asymmetries in the $B^\pm \to \pi^\pm K$ channels
are about 2% based on perturbative calculation. Rescattering effects might
enhance it to at most (20-25)%. We show that lepton-number-violating $\lambda'$
couplings in supersymmetric models are capable of enhancing it to as large as
100%. Upcoming B factories will test this scenario.


title:
Large extra dimensions and dijet production in $\gamma \gamma$
  collisions

abstract:
  We have studied dijet production in $\gamma \gamma$ collisions with a view to
probing the physics of large extra dimensions. The exchange of virtual spin-2
Kaluza-Klein excitations is found to modify the dijet cross-section
substantially from its Standard Model value and allows the effective string
scale to be probed to values between 2.5 and 6.4 TeV in the unpolarised case.
In the case where the photons are polarised, the limits are seen to improve by
roughly 20%. Dijet production in $\gamma \gamma$ collisions is thus shown to be
a very effective probe of large extra dimensions.


title:
The Inverse Amplitude Method and Heavy Baryon Chiral Perturbation Theory
  applied to pion-nucleon scattering

abstract:
  We report on our present work, where by means of the Inverse Amplitude Method
we unitarize the elastic pion nucleon scattering amplitudes of Heavy Barion
Chiral Perturbation Theory at O(q^3). We reproduce the scattering up to the
inelastic thresholds including the Delta(1232) resonance. The fitted chiral
constants are rather different from those obtained by fitting the extrapolated
threshold parameters for the non-unitarized theory.


title: Preon Trinity - a new model of leptons and quarks

abstract:
  A new model for the substructure of quarks, leptons and weak gauge bosons is
discussed. It is based on three fundamental and absolutely stable spin-1/2
preons. Its preon flavour SU(3) symmetry leads to a prediction of nine quarks,
nine leptons and nine heavy vector bosons. One of the quarks has charge
$-4e/3$, and is speculated to be the top quark (whose charge has not been
measured). The flavour symmetry leads to three conserved lepton numbers in all
known weak processes, except for some neutrinos, which might either oscillate
or decay. There is also a (Cabibbo) mixing of the $d$ and $s$ quarks due to an
internal preon-antipreon annihilation channel. An identical channel exists
inside the composite $Z^0$, leading to a relation between the Cabibbo and
Weinberg mixing angles.


title:
Quasi-infra-red fixed points and renormalisation group invariant
  trajectories for non-holomorphic soft supersymmetry breaking

abstract:
  In the MSSM the quasi-infra-red fixed point for the top-quark Yukawa coupling
gives rise to specific predictions for the soft-breaking parameters. We discuss
the extent to which these predictions are modified by the introduction of
additional ``non-holomorphic'' soft-breaking terms. We also show that in a
specific class of theories there exists an RG-invariant trajectory for the
``non-holomorphic'' terms, which can be understood using a holomorphic spurion
term.


title: High Energy Theorems at Large-N

abstract:
  Sum rules for products of two, three and four QCD currents are derived using
chiral symmetry at infinite momentum in the large-N limit. These exact
relations among meson decay constants, axialvector couplings and masses
determine the asymptotic behavior of an infinite number of QCD correlators. The
familiar spectral function sum rules for products of two QCD currents are among
the relations derived. With this precise knowledge of asymptotic behavior, an
infinite number of large-N QCD correlators can be constructed using dispersion
relations. A detailed derivation is given of the exact large-N pion vector form
factor and forward pion-pion scattering amplitudes.


title: APACIC++, A Parton Cascade in C++

abstract:
  In this talk the newly developped Monte-Carlo event generator {\tt APACIC++}
suitable to describe multijet-events in high-energetic electron-positron
annihilations is presented. A new ansatz to match the corresponding matrix
elements for the production of jets via the strong and electroweak interactions
to the subsequent parton shower modelling the inner-jet evolution is discussed
in some detail. Results obtained with {\tt APACIC++} are compared to other QCD
event generators and to some representative experimental data.


title:
Probing the Space-Time evolution of Heavy Ion Collisions with
  Bremsstrahlung

abstract:
  We examine the bremsstrahlung photons emitted in the central collisions of
two gold nuclei at the Relativistic Heavy Ion Collider. While the measurements
of the final hadrons can reveal only the amount of stopping, they tell us very
little about the space-time evolution of the bulk matter in the collisions. By
using two extreme collision scenarios, we argue that the low and medium energy
bremsstrahlung photons can, not only reveal the amount of stopping, but also
the finer details of the space-time evolution of the charges.


title: Patterns of Symmetry Breaking in QCD at High Baryon Density

abstract:
  We study the structure of QCD at very large baryon density for an arbitrary
number of flavors $N_f$. We provide evidence that for any number of flavors
larger than $N_f=2$ chiral symmetry remains broken at asymptotically large
chemical potential. For $N_c=N_f=3$, chiral symmetry breaking follows the
standard pattern $SU(3)_L\times SU(3)_R\to SU(3)$, but for $N_f>3$ unusual
patterns emerge. We study the case $N_f=3$ in more detail and calculate the
magnitude of the chiral order parameters $<\bar\psi\psi>$ and
$<(\bar\psi\psi)^2>$ in perturbative QCD. We show that, asymptotically,
$<\bar\psi\psi>^{1/3}$ is much smaller than $<(\bar\psi\psi)^2>^{1/6}$. The
result can be understood in terms of an approximate discrete symmetry.


title:
Penguins diagrams in Delta I=1/2 rule and \epsilon'/\epsilon with \sigma
  models

abstract:
  We study the correlation between $\epe$ and $\Delta I=1/2$ rule in the
framework of non-linear $\sigma$ model including scalar mesons. The matrix
elements of QCD and Electroweak (EW) penguin operators are computed within
factorization approximation. Using the matrix elements and changing the scalar
meson mass, we find that there is correlation between $\epe$ and $\Delta I=1/2$
amplitude. However, it is difficult to explain both $\epe$ and $\Delta I=1/2$
amplitude simultaneously. In order to be compatible with $\epe$, typically,
about half of $\Delta I=1/2$ amplitude can be explained at most. Our result
suggests there may be substantial non-factorizable contribution to CP
conserving $K \to \pi \pi$ amplitudes.


title: On Basic Concepts of the Quasiclassical Operator Approach

abstract:
  We present a derivation of the probability of bremsstrahlung from high-energy
electrons in a screened Coulomb field using the quasiclassical operator method.
It is shown that recent Zakharov's criticism is completely groundless and comes
from misunderstanding of the method. We confirm all our published results.


title:
Discretized light-cone quantization and the effective interaction in
  hadrons

abstract:
  Light-cone quantization of gauge theories is discussed from two perspectives:
as a calculational tool for representing hadrons as QCD bound-states of
relativistic quarks and gluons, and as a novel method for simulating quantum
field theory on a computer. A general non-perturbative method for numerically
solving quantum field theories, `discretized light-cone quantization', is
outlined. Both the bound-state spectrum and the corresponding relativistic
wavefunctions can be obtained by matrix diagonalization and related techniques.
Emphasis is put on the construction of the light-cone Fock basis and on how to
reduce the many-body problem to an effective Hamiltonian. The usual divergences
are avoided by cut-offs and subsequently removed by the renormalization group.
For the first time, this programme is carried out within a Hamiltonian
approach, from the beginning to the end. Starting with the QCD-Lagrangian, a
regularized effective interaction is derived and renormalized, ending up with
an almost solvable integral equation.Its eigenvalues yield the mass spectrum of
physical mesons, its eigenfunctions yield their wavefunctions including the
higher Fock-space components. An approximate but analytic mass formula is
derived for all physical mesons.


title: Asymptotic scaling of the gluon propagtor on the lattice

abstract:
  We pursue the study of the high energy behaviour of the gluon propagator on
the lattice in the Landau gauge in the flavorless case (n_f=0). It was shown in
a precedin g paper that the gluon propagator did not reach three-loop
asymptotic scaling at an energy scale as high as 5 GeV.
  Our present high statistics analysis includes also a simulation at
$\beta=6.8$ ($a\simeq 0.03$ fm), which allows to reach $\mu \simeq 10$ GeV.
Special care has been devoted to the finite lattice-spacing artifacts as well
as to the finite volume effects, the latter being acute at $\beta=6.8$ where
the volume is bounded by technical limits. Our main conclusion is a strong
evidence that the gluon propagator has reached three-loop asymptotic scaling,
at $\mu$ ranging from 5.6 GeV to 9.5 GeV. We buttress up this conclusion on
several demanding criteria of asymptoticity, including scheme independence. Our
fit in the 5.6 GeV to 9.5 GeV window yields $\Lambda^{\bar{{\rm MS}}} =
  319 \pm 14 ^{+10}_{-20}$ MeV, in good agreement with our previous result,
$\Lambda^{\bar{{\rm MS}}} = 295 \pm 20 $ MeV, obtained from the three gluon
vertex, but it is significantly above the Schr\"odinger functional method
estimate : $238 \pm 19$ MeV. The latter difference is not understood.
Confirming our previous paper, we show that a fourth loop is necessary to fit
the whole ($2.8 \div 9.5$) GeV energy window.


title: GENIUS - a Supersensitive Germanium Detector System for Rare Events

abstract:
  To increase by a major step the present sensitivity for dark matter and
double beta decay search, a new project is suggested, which would operate
'naked' GErmanium detectors in liquid NItrogen as shielding in an Underground
Setup (GENIUS). In a first step using 100 kg of natural Ge a large part of the
MSSM parameter space for prediction of neutralinos as cold dark matter will be
covered making the experiment complementary to LHC in the search for
supersymmetry. In the second step use of one ton of enriched 76Ge would yield a
sensitivity for double beta decay for the effective Majorana neutrino mass of
\0.01 eV. This would be a breakthrough for neutrino physics. GENIUS would also
be a breakthrough into the multi-TeV range for many other beyond standard
models currently discussed, and the sensitivity would be comparable or even
superior to LHC or NLC for various quantities such as right-handed W boson
mass, R-parity violation, leptoquark or compositeness searches, or left-handed
heavy neutrinos.


title:
Two Photon Radiation in W and Z Boson Production at the Tevatron
  Collider

abstract:
  We present a calculation of two photon radiation in W and Z boson production
in hadronic collisions, based on the complete matrix elements for the processes
q\bar q'\to\ell^\pm\nu\gamma\gamma and q\bar q\to\ell^+\ell^-\gamma\gamma,
including finite charged lepton masses. In order to achieve stable numerical
results over the full phase space, multiconfiguration Monte Carlo techniques
are used to map the peaks in the differential cross section. Numerical results
are presented for the Fermilab Tevatron.


title: Constraints on Extra Time Dimensions

abstract:
  We discuss phenomenology of extra time dimensions in a scenario where the
standard model particles are localized in ``our'' time, whereas gravity can
propagate in all time dimensions. For an odd number of extra times, at small
distances, the (real part of the) Newtonian potential is ``screened'' by
tachyonic Kaluza-Klein gravitons. In general, the gravitational self-energy of
objects acquires an imaginary part. This complexity may either be interpreted
as an amplitude for the disappearance into ``nothing'', leading to the
causality and probability violation in low-energy processes, or as an artifact
of the fictitious decay into the unphysical negative energy tachyons. The
former case would put the most severe phenomenological restrictions on such
theories. In the latter case the size of extra times may be within the reach of
the proposed gravitational experiments. In such a case these experiments should
observe that the strength of the Newtonian gravity diminishes at short
distances.


title: Variational Principle for Relativistic Fluid Dynamics

abstract:
  The variational principle for the special and general relativistic
hydrodynamics are discussed in view of its application to obtain approximate
solutions to these problems. We show that effective Lagrangians can be obtained
for suitable ansatz for the dynamical variables such as density profile of the
system. As an example, the relativistic version of spherical droplet motion
(Rayleigh-Plesset equation) is derived from a simple Lagrangian. For the
general relativistic case the most general Lagrangian for spherically symmetric
systems is given.


title: Renormalization group scaling in nonrelativistic QCD

abstract:
  We discuss the matching conditions and renormalization group evolution of
non-relativistic QCD. A variant of the conventional MS-bar scheme is proposed
in which a subtraction velocity nu is used rather than a subtraction scale mu.
We derive a novel renormalization group equation in velocity space which can be
used to sum logarithms of v in the effective theory. We apply our method to
several examples. In particular we show that our formulation correctly
reproduces the two-loop anomalous dimension of the heavy quark production
current near threshold.


title:
Charm production in the semi-hard approach of QCD and the unintegrated
  gluon distribution

abstract:
  In the framework of semi-hard QCD approach, we present a consistent analysis
of D^* meson production at HERA energies. The consideration is based on
universal unintegrated gluon densities, which have BFKL behavior in the small x
region. Predictions of the CCFM evolution equation for D^* production are
obtained and show a good description of D^* data at HERA.


title:
Anatomy of Mixing-Induced CP Asymmetries in Left-Right-Symmetric Models
  with Spontaneous CP Violation

abstract:
  We investigate the pattern of CP violation in K, B_d and B_s mixing in a
symmetrical SU(2)_R x SU(2)_L x U(1) model with spontaneous CP violation. We
calculate the phases of the left and right quark mixing matrices beyond the
small phase approximation and perform a careful analysis of all relevant
restrictions on the model's parameters from Delta m_K, Delta m_B, epsilon,
epsilon'/epsilon and the CP asymmetry in B->J/psi K_S. We find that, with
current experimental data, the mass of the right-handed charged gauge boson,
M2, is restricted to be in the range 2.75 to 13 TeV and the mass of the
flavour-changing neutral Higgs boson, MH, in 10.2 to 14.6 TeV. This means in
particular that the decoupling limit M2, MH -> infinity is already excluded by
experiment. We also find that the model favours opposite signs of epsilon and
sin 2beta and is excluded if sin 2beta > 0.1.


title: Exclusive Hadronic Reactions at High $Q^2$

abstract:
  The observed scaling laws for large angle exclusive hadronic reactions are
successfully accounted for by the short-distance QCD quark interchange
processes. We focus on three hadronic reactions which shows evidence for a
slight oscillatory deviation from the expected scaling behaviour. Possible
explanations for these oscillations and connections to spin observables will be
mentioned. Better data from excisting facilities (or a possible future KEK
proton accelerator, JHP) can clarify the theoretical situation.


title:
Lepton Flavor Violation in the Standard Model Extended by Heavy Singlet
  Dirac Neutrinos

abstract:
  Low energy neutrinoless lepton flavor violating (LFV) processes are studied
in an extension of the Standard Model (SM) by heavy SU(2)xU(1) singlet Dirac
neutrinos. An upper bound procedure is elaborated for the evaluation of
amplitudes. A comment on the extraction of heavy neutrino mixings from
astrophysical observations is given. For processes not treated in the applied
model the formalism not treated in the applied model the formalism for
evaluating the branching ratios (BRs) is presented. The processes previously
studied in the model are carefully examined. Some of the previous results are
improved. Special attention is paid to the structure of the amplitudes and BRs
as well as to the relations between BRs of different LFV processes. Numerical
analysis of the BRs is done. The decoupling of heavy neutrinos is discussed and
it is explicitely shown that the very heavy neutrinos decouple when the upper
bound procedure is applied. The upper limits of the BRs are compared with the
current experimental upper bounds and the processes interesting for the search
for LFV are proposed. The LFV decays are shown to be unsuitable for finding
upper bounds on "diagonal" LFV parameters. The B-meson LFV processes are
suggested for the search of LFV in future B-factories.


title: Preheating of the nonminimally coupled inflaton field

abstract:
  We investigate preheating of an inflaton field $\phi$ coupled nonminimally to
a spacetime curvature. In the case of a self-coupling inflaton potential
$V(\phi)=\lambda \phi^4/4$, the dynamics of preheating changes by the effect of
the negative $\xi$. We find that the nonminimal coupling works in two ways.
  First, since the initial value of inflaton field for reheating becomes
smaller with the increase of $|\xi|$, the evolution of the inflaton quanta is
delayed for fixed $\lambda$. Second, the oscillation of the inflaton field is
modified and the nonadiabatic change around $\phi=0$ occurs significantly. That
makes the resonant band of the fluctuation field wider. Especially for strong
coupling regimes $|\xi| \gg 1$, the growth of the inflaton flutuation is
dominated by the resonance due to the nonminimal coupling, which leads to the
significant enhancement of low momentum modes. Although the final variance of
the inflaton fluctuation does notchange significantly compared with the
minimally coupled case, we have found that the energy transfer from the
homogeneous inflaton to created particles efficiently occurs for $\xi<-60$.


title: Testing quark mass matrices with right-handed mixings

abstract:
  In the standard model, several forms of quark mass matrices which correspond
to the choice of weak bases lead to the same left-handed mixings $V_L=V_{CKM}$,
while the right-handed mixings $V_R$ are not observable quantities. Instead, in
a left-right extension of the standard model, such forms are ansatze and give
different right-handed mixings which are now observable quantities. We
partially select the reliable forms of quark mass matrices by means of
constraints on right-handed mixings in some left-right models, in particular on
$V^R_{cb}$. Hermitian matrices are easily excluded.


title: Chiral symmetry breaking and instantons in both quenched and full QCD

abstract:
  We investigate the contribution that instantons make to the QCD chiral
condensate for Nf= 0, 1 and 2 quark flavours. We use a simplified model: the
instantons are a (weighted) gas, the fermionic integrations are restricted to
the subspace spanned by the would-be zero-modes and only the dimensional and
chiral features of the Dirac operator are retained. Previous work along these
lines found a power-like divergence of the Dirac spectral density at zero
eigenvalue. By changing the various components of the model, we show that a
power divergence appears to be a generic feature of instanton mixing for both
Nf=0 and Nf=/=0. In the latter case the divergence disappears as m->0 in such a
way that psibar-psi remains finite. We find that the exponent of the power
decreases for larger instanton densities, becoming negligible for very dense
instanton `gases'. We reproduce the expected m-dependence of the topological
susceptibility, we investigate the space-time structure of the eigenfunctions,
as a function of the eigenvalue, and we calculate the eta-prime mass. In
summary: instantons appear to provide a natural mechanism for the spontaneous
breaking of chiral symmetry in QCD, but they typically produce a power-like
divergence in the Dirac spectral density. This divergence is non-standard but
`harmless' in the case of full QCD, and implies a pathology in the case of
quenched QCD.


title: Entropy in cluster analysis of single events in heavy ion collisions

abstract:
  We analyse the cluster structure of the final multihadron states resulting
from heavy ion collisions using the concept of Jaynes - Shannon entropy.
Further evidence for an interesting differentiation of events is provided.


title:
Analysis of the exclusive semileptonic decay Lambda_b -> Lambda_c + l
  nu_l within a light-front constituent quark model

abstract:
  The exclusive semileptonic decay Lambda_b -> Lambda_c + l nu_l is
investigated including both radiative and first-order power corrections in the
inverse heavy-quark mass, while the Isgur-Wise function is calculated within a
light-front constituent quark model. It turns out that the dependence on the
model parameters can be effectively constrained using recent lattice QCD
results at low values of the recoil. Our final predictions for the exclusive
semileptonic branching ratio, the longitudinal and transverse asymmetries, and
the longitudinal to transverse decay ratio are: Br(Lambda_b -> Lambda_c + l
nu_l) = (6.3 \pm 1.6) % |V_{bc} / 0.040|**2 \tau(\Lambda_b) / (1.24 ps), a_L =
-0.945 \pm 0.014, a_T = -0.62 \pm 0.09 and R_L/T = 1.57 \pm 0.15, respectively.
Moreover, the theoretical uncertainties both on a_L and the (partially
integrated) R_L/T are found to be quite small and, therefore, the experimental
determination of these quantities is a very interesting tool for testing the
Standard Model and for investigating possible New Physics. In this respect the
sensitivity to extract unique information both on the strength and phase of
possible hadronic right-handed currents is illustrated.


title: Standard Sources of Particle Production in Heavy Ion Collisions

abstract:
  We describe particle production in the framework of an independent string
model: the dual parton model. We show that an improved version of this model,
containing a diquark breaking component, allows to describe the bulk of
particle production and, in particular, baryon stopping and most of the
observed enhancement of strange baryons. Only for very rare processes, such as
$\Omega$ or $J/\psi$ production, the model has to be supplemented with final
state interaction (comovers interaction). Recent data on event-by-event
fluctuations in $p_{T}$ are also described by the model. Predictions for RHIC
and LHC are presented and the effect of nuclear shadowing is discussed.


title:
Photonic penguins at two loops and m_t-dependence of BR[ B -> X_s l^+
  l^-]

abstract:
  We calculate two-loop matching conditions for all the operators that are
relevant to B -> X_s l^+ l^- decay in the Standard Model. In effect, we are
able to remove the +_16% uncertainty in the decay spectrum, which was mainly
due to the renormalization-scale dependence of the top-quark mass. We find 1.46
* 10^-6 for the branching ratio integrated in the domain 0.05 <
m_{l^+l^-}^2/m_b^2 < 0.25, for l= e or mu. There remains around 13%
perturbative uncertainty in this quantity, while the non-perturbative effects
are expected to be smaller.


title:
A Comparative Study of the Decays $B \to (K,K^*) \ell^+ \ell^-$ in
  Standard Model and Supersymmetric Theories

abstract:
  Using improved theoretical calculations of the decay form factors in the
Light Cone-QCD sum rule approach, we investigate the decay rates, dilepton
invariant mass spectra and the forward-backward (FB) asymmetry in the decays $B
\to (K,K^*) \ell^+ \ell^-$ ($\ell^\pm =e^\pm,\mu^\pm,\tau^\pm$) in the standard
model (SM) and a number of popular variants of the supersymmetric (SUSY)
models. Theoretical precision on the differential decay rates and FB-asymmetry
is estimated in these theories taking into account various parametric
uncertainties. We show that existing data on $B \to X_s \gamma$ and the
experimental upper limit on the branching ratio ${\cal B}(B \to K^* \mu^+
\mu^-)$ provide interesting bounds on the coefficients of the underlying
effective theory. We argue that the FB-asymmetry in $B \to K^* \ell^+ \ell^-$
constitutes a precision test of the SM and its measurement in forthcoming
experiments may reveal new physics. In particular, the presently allowed
large-$\tan \beta$ solutions in SUGRA models, as well as more general
flavor-violating SUSY models, yield FB-asymmetries which are characteristically
different from the corresponding ones in the SM.


title:
Review of different approaches to understanding the phenomenon of
  diffraction

abstract:
  This brief review of hard diffraction is focussed on the theory of the
diffractive structure function F_2^D. Some aspects of diffractive vector meson
production and of diffractive processes in hadron-hadron collisions are also
discussed.


title:
Single mass scale diagrams: construction of a basis for the
  $\epsilon$-expansion

abstract:
  Exploring the idea of Broadhurst on the ``sixth root of unity'' we present an
ansatz for construction of a basis of transcendental numbers for the
epsilon-expansion of single mass scale diagrams with two particle massive cut.
As example, several new two- and three-loop master integrals are calculated.


title:
Explicit results for all orders of the epsilon-expansion of certain
  massive and massless diagrams

abstract:
  An arbitrary term of the epsilon-expansion of dimensionally regulated
off-shell massless one-loop three-point Feynman diagram is expressed in terms
of log-sine integrals related to the polylogarithms. Using magic connection
between these diagrams and two-loop massive vacuum diagrams, the
epsilon-expansion of the latter is also obtained, for arbitrary values of the
masses. The problem of analytic continuation is also discussed.


title:
On gap equations and color-flavor locking in cold dense QCD with three
  massless flavors

abstract:
  The superconductivity in cold dense QCD with three massless flavors is
analyzed in the framework of the Schwinger-Dyson equation. The set of two
coupled gap equations for the color antitriplet, flavor antitriplet
(bar{3},bar{3}) and the color sextet, flavor sextet (6,6) order parameters is
derived. It is shown that the antitriplet-antitriplet gives the dominant
contribution to the color-flavor locked order parameter, while the
sextet-sextet is small but nonzero.


title: Evolution of average multiplicities of quark and gluon jets

abstract:
  The energy evolution of average multiplicities of quark and gluon jets is
studied in perturbative QCD. Higher order (3NLO) terms in the perturbative
expansion of equations for the generating functions are found. First and second
derivatives of average multiplicities are calculated. The mean multiplicity of
gluon jets is larger than that of quark jets and evolves more rapidly with
energy. It is shown which quantities are most sensitive to higher order
perturbative and nonperturbative corrections. We define the energy regions
where the corrections to different quantities are important. The latest
experimental data are discussed.


title: Loop Calculations with FeynArts, FormCalc, and LoopTools

abstract:
  Three programs are presented for automatically generating and calculating
Feynman diagrams: the diagrams are generated with FeynArts, algebraically
simplified with FormCalc, and finally evaluated numerically using the LoopTools
package. The calculations are performed analytically as far as possible, with
results given in a form well suited for numerical evaluation. The latter is
then straightforward using the implementations of the one-loop integrals in
LoopTools.


title: Measuring the Higgs Yukawa Couplings at a Next Linear Collider

abstract:
  We investigate the inclusive production of a Higgs boson with a pair of heavy
quarks (t-tbar b-bbar), in e^+e^- collisions at high energies, sqrt(s)=500 GeV
and sqrt(s)=1 TeV. We consider both the Standard Model and the supersymmetric
case. In both cases O(alpha_s) QCD corrections are included. The associated
production of a Higgs boson with a t-tbar pair is extremely sensitive to the
top-Higgs Yukawa coupling and may allow the precision measurement of this
coupling. In some regions of the supersymmetric parameter space the associated
production of a Higgs boson with a b-bbar pair receives large resonant
contributions and can have a significant rate.


title: Can Induced Theta Vacua be Created in Heavy Ion Collisions?

abstract:
  The development of the early Universe is a remarkable laboratory for the
study of most nontrivial properties of particle physics. What is more
remarkable is the fact that these phenomena at the QCD scale can be, in
principle, experimentally tested in heavy ion collisions. We expect that, in
general, an arbitrary theta-state would be created in the heavy ion collisions,
similar to the creation of the disoriented chiral condensate with an arbitrary
isospin direction. It should be a large domain with a wrong $\theta\neq 0$
orientation. We test this idea numerically in a simple model where we study the
evolution of the phases of the chiral condensates in QCD with two quark flavors
with non-zero theta-parameter. We see the formation of a non-zero theta-vacuum
with the formation time of the order of $10^{-23}$ seconds. This result will
have important implications for a possible axion search experiment at RHIC.


title: A Minimal Superstring Standard Model II: A Phenomenological Study

abstract:
  Recently, we demonstrated the existence of heterotic--string solutions in
which the observable sector effective field theory just below the string scale
reduces to that of the MSSM, with the standard observable gauge group being
just SU(3)_C x SU(2)_L x U(1)_Y and the SU(3)_C x SU(2)_L x U(1)_Y-charged
spectrum of the observable sector consisting solely of the MSSM spectrum.
Associated with this model is a set of distinct flat directions of vacuum
expectation values (VEVs) of non-Abelian singlet fields that all produce solely
the MSSM spectrum. In this paper, we study the effective superpotential induced
by these choices of flat directions. We investigate whether sufficient degrees
of freedom exist in these singlet flat directions to satisfy various
phenomenological constraints imposed by the observed Standard Model data. For
each flat direction, the effective superpotential is given to sixth order. The
variations in the singlet and hidden sector low energy spectrums are analyzed.
We then determine the mass matrices (to all finite orders) for the three
generations of MSSM quarks and leptons. Possible Higgs mu-terms are
investigated. We conclude by considering generalizations of our flat directions
involving VEVs of non-Abelian fields.


title: Fixed points in the evolution of neutrino mixings

abstract:
  We derive the renormalization group equations for the neutrino masses and
mixing angles in explicit form and discuss the possible classes of their
solutions. We identify fixed points in the equations for mixing angles, which
can be reached during the evolution for several mass patterns and give
$\sin^22\theta_{sol}=\sin^22\theta_{atm}\sin^2\theta_3/
(\sin^2\theta_{atm}\cos^2\theta_3 + \sin^2\theta_3)^2$, consistently with the
present experimental information. Further experimental test of this relation is
of crucial interest. Moreover, we discuss the stability of quantum corrections
to neutrino mass squared differences. Several interesting mass patterns show
stability in the presence of fixed point solutions for the angles.


title: CP Violation in Hyperon Decays

abstract: The theory and phenomenology of CP violation in hyperon decays is summarized.


title: Probing lepton flavour violation with Higgs boson decays H-> li+lj

abstract:
  We evaluate the lepton flavour violating (LFV) decays of HIggs bosons
H->li+lj in several extensions of the SM, including both the effective
lagrangian approach and several specific models. For the effective lagrangian
case, we focus on dimension-six operators that induce LFV vertices for the
Higgs and or Z bosons. For those operators whose coefficients can not be
constrained by present data, LFV Higgs decays can have a B.R. of order
0.1-0.01. Those cases when current bounds apply, induce strong bounds for e-mu
transitions, and the b.r. for H->e mu is of order 10^-9; however H->tau mu, tau
e, can have B.R. of order 0.1. In the case of the two-higgs doublet model III,
we obtain a similar B.R. for H-> tau mu, tau e, whereas in the SM with massive
neutrinos and the minimal SUSY-SM the corresponding B.R. are very suppressed.


title: On the Geometry Origin of Weak CP Phase

abstract:
  In this work, the postulation that weak CP phase originates in a certain
geometry, is further discussed. Some intrinsic and strict constraints on the
mixing angles, weak CP phase, and the Wolfenstein's parameters $\rho$ and
$\eta$ are given by present data and the postulation itself. Especially, we
predict $0.0076 \leq |V_{td}| \leq 0.0093, 74.9^o \leq \gamma \leq 75.7^o$ when
the corresponding inputs are at the $90% C. L.$. The comparison of the
predictions to the relevant experimental and theoretical results is listed. All
the predictions coincide with the present experimental results and theoretical
analysis very well.


title:
Can Geodesics in Extra Dimensions Solve the Cosmological Horizon
  Problem?

abstract:
  We demonstrate a non-inflationary solution to the cosmological horizon
problem in scenarios in which our observable universe is confined to three
spatial dimensions (a three-brane) embedded in a higher dimensional space. A
signal traveling along an extra-dimensional null geodesic may leave our
three-brane, travel into the extra dimensions, and subsequently return to a
different place on our three-brane in a shorter time than the time a signal
confined to our three-brane would take. Hence, these geodesics may connect
distant points which would otherwise be ``outside'' the four dimensional
horizon (points not in causal contact with one another).


title:
Combined analysis of the unitarity triangle and CP violation in the
  Standard Model

abstract:
  We perform a combined analysis of the unitarity triangle and of the CP
violating parameter epsilon'/epsilon using the most recent determination of the
relevant experimental data and, whenever possible, hadronic matrix elements
from lattice QCD. We discuss the role of the main non-perturbative parameters
and make a comparison with other recent analyses. We use lattice results for
the matrix element of Q_8 obtained without reference to the strange quark mass.
Since a reliable lattice determination of the matrix element of Q_6 is still
missing, the theoretical predictions for epsilon'/epsilon suffer from large
uncertainties. By evaluating this matrix element with the vacuum-saturation
approximation, we typically find as central value epsilon'/epsilon = (4 - 7) x
10^(-4). We conclude that the experimental data suggest large deviation of the
value of the matrix element of Q_6 from the vacuum-saturation approximation,
possibly due to penguin contractions.


title: Epsilon'/epsilon from Lattice QCD

abstract:
  Lattice calculations of matrix elements relevant for kaon decays, and in
particular for epsilon'/epsilon, are reviewed. The role of the strange quark
mass is also discussed. A comparison with other non-perturbative approaches
used to compute kaon decay amplitudes is made.


title: The Heavy Quarkonium Spectrum at Order $m\alpha_s^5 \ln \alpha_s$

abstract:
  We compute the complete leading-log terms of the
next-to-next-to-next-to-leading-order corrections to potential NRQCD. As a
by-product we obtain the leading logs at $O(m\alpha_s^5)$ in the heavy
quarkonium spectrum. These leading logs, when $\Lambda_{QCD} \ll m\alpha_s^2$,
give the complete $O(m\alpha_s^5 \ln \alpha_s)$ corrections to the heavy
quarkonium spectrum.


title: Heavy Quarkonium and Nonrelativistic Effective Field Theories

abstract:
  We study some general aspects of the formalism of potential NRQCD (pNRQCD),
an effective field theory that deals with ultrasoft degrees of freedom in Heavy
Quarkonium systems. Specific attention is paid to its effective Lagrangian that
it is displayed at the present level of accuracy.


title: Resummation for direct photon and W + jet production

abstract:
  I discuss the resummation of soft gluon contributions to direct photon and W
+ jet production and I present some results for the next-to-next-to-leading
order expansions of the resummed cross sections for these processes near
threshold.


title: Strong Interaction Effects in Scalar Top Production

abstract:
  We discuss effects of fragmentation and hard gluon radiation on the signal
for the pair production of the lighter scalar top eigenstate $\tilde{t}_1$ at
e^+e^- colliders. The main emphasis is on scenarios with small stop--LSP mass
splitting, where strong interaction effects can considerably modify kinematical
properties of the final state.


title: Dynamical generation of the gauged SU(2) linear sigma model

abstract:
  The fermion and meson sectors of the quark-level SU(2) linear sigma model are
dynamically generated from a meson-quark Lagrangian, with the quark (q) and
meson ($\sigma,\pi$) fields all treated as elementary, having neither bare
masses nor expectation values. In the chiral limit, the masses are predicted to
be $m_q = f_\pi g, m_\pi = 0, m_\sigma = 2m_q$, and we also find that the
quark-meson coupling $g = 2\pi/sqrt{N_c}$, the three-meson coupling is $g' =
m_\sigma^2/2f_\pi = 2gm_q$ and the four-meson coupling is $\lambda = 2g^2 =
g'/f_\pi$, where $f_\pi \simeq 90$ MeV is the pion decay constant and $N_c = 3$
is the color number. By gauging this model one can generate the couplings to
the vector mesons $\rho$ and $A_1$, including the quark-vector coupling
constant $g_\rho = 2\pi, g_{\rho\pi\pi}, g_{A_1\rho\pi}$ and the masses
$M_\rho\sim 700$ MeV, $m_{A_1}\simeq \sqrt{3}m_\rho$; of course the vector and
axial vector currents remain conserved throughout.


title: Pion Interactions in Chiral Field Theories

abstract:
  We study in various chiral models the pion charge radius, $\pi_{e3}$ form
factor ratio, $\pi^\circ \to \gamma \gamma$ amplitude, charge pion
polarizabilities, $\gamma\gamma \to \pi^\circ \pi^\circ$ amplitude at low
energies and the $\pi\pi$ s-wave I = 0 scattering length. We find that a
quark-level linear sigma-model approach (also being consistent with tree-level
vector meson dominance) is quite compatible with all of the above data.


title: Kaon Weak Decays in Chiral Theories

abstract:
  The ten nonleptonic weak decays $K \to 2\pi$, $K \to 3\pi$, $K_L \to
2\gamma$, $K_S \to 2\gamma$, $K_L \to \pi^\circ 2\gamma$, are predicted for a
chiral pole model based on the linear sigma model theory which automatically
satisfies the partial conservation of axial current (PCAC) hypothesis. These
predictions, agreeing with data to the 5% level and containing no or at most
one free parameter, are compared with the results of chiral perturbation theory
(ChPT). The latter ChPT approach to one-loop level is known to contain at least
four free parameters and then predicts a $K_L \to \pi^\circ \gamma\gamma$ rate
which is 60% shy of the experimental value. This suggests that ChPT is an
unsatisfactory approach towards predicting kaon weak decays.


title: A Method For Extracting cos\alpha

abstract:
  We show that it is possible to extract the weak mixing angle alpha via a
measurement of the rate for B^+(-) -> \pi^+(-) e^+e^-. The sensitivity to
cos(alpha) results from the interference between the long and short distance
contributions. The short distance contribution can be computed, using heavy
quark symmetry, in terms of semi-leptonic form factors. More importantly, we
show that, using Ward identities and a short distance operator product
expansion, the long distance contribution can be calculated without recourse to
light cone wave functions when the invariant mass of the lepton pair, q^2, is
much larger than LQCDs. We find that for q^2 > 2 GeV^2 the branching fraction
is approximately 1 * 10^{-8}|V_{td}/0.008|^2. The shape of the differential
rate is very sensitive to the value of cos(alpha) at small values of q^2 with
dGamma /dq^2 varying up to 50% in the interval
  -1< cos(alpha)< 1 at q^2= 2 GeV^2. The size of the variation depends upon the
ratio V_{ub}/V_{td}.


title: Neutrino Anomalies without Oscillations

abstract:
  I review explanations for the three neutrino anomalies (solar, atmospheric
and LSND) which go beyond the ``conventional'' neutrino oscillations induced by
mass-mixing. Several of these require non-zero neutrino masses as well.


title: Color Superconductivity in Asymmetric Matter

abstract:
  The influence of different chemical potential for different flavors on color
superconductivity is analyzed.
  It is found that there is a first order transition as the asymmetry grows.
This transition proceeds through the formation of bubbles of low density,
flavor asymmetric normal phase inside a high density, superconducting phase
with a gap {\it larger} than the one found in the symmetric case. For small
fixed asymmetries the system is normal at low densities and superconducting
only above some critical density. For larger asymmetries the two massless
quarks system stays in the mixed state for arbitrarily high densities.


title: Effect of sigma(600)-Production in pp_bar to 3pi0 at rest

abstract:
  The pi0 pi0 mass spectra and angular distributions around KK_bar-threshold
and at 1.5 GeV in pp_bar(at rest) to 3pi0 in the Crystal Barrel experiment are
reanalyzed by applying the new method, which is consistent with unitarity of
S-matrix and expressed directly by resonance parameters. The effects of light
sigma-meson production are clearly seen to improve the fit with sigma, in
comparing with the fit without sigma.


title:
Influence of the re-scattering process on polarization observables in
  reaction gamma + d --> p + p + pi- in Delta - resonance region

abstract:
  Influence of the effects of the pion-nucleon and nucleon-nucleon
re-scattering on the polarization observables of the reaction gamma + d = p + p
+ pi- in Delta - isobar region is investigated. Pion-nucleon and
nucleon-nucleon re-scattering are studied in the diagrammatic approach.
Relativistic-invariant forms of the pion photoproduction and pion-nucleon
scattering operators are used. The unitarization procedure in K-matrix approach
is applied for the resonance partial amplitudes. It is shown a considerable
influence of the re-scattering effects on the polarization observables of this
reaction in the Delta - resonance region for the large momenta of the final
protons.


title:
Comparison between variable flavor number schemes for charm quark
  electroproduction

abstract:
  Where appropriate, the abbreviation 'VFNS' is replaced by 'CSN' to indicate
the scheme using massive heavy quark coefficient functions proposed in this
paper. The text below Eq. (2.13) and between Eqs. (2.33) and (2.36) has been
considerably changed.


title: Predicting F2D(3) from the dipole cross-section

abstract:
  We employ a parameterisation of the proton dipole cross section previously
extracted from electroproduction and photoproduction data to predict the
diffractive structure function F2D(3)(Q^2, beta, xpom). Comparison with HERA H1
data yields good agreement.


title:
Large-p_T Inclusive pi^0 Cross Sections and Next-to-Leading-Order QCD
  Predictions

abstract:
  We review the phenomenology of pi^0 production at large transverse momentum
in proton-induced collisions. Uncertainties in the next-to-leading-order
predictions of Quantum Chromodynamics are discussed. The comparison with data
reveals that the disagreement between theory and experiment lies essentially in
an overall normalization factor. The situation for pi^0 production is
contrasted with that of prompt-photon production in hadronic collisions.


title: Multi-Photon Amplitudes for Next-to-Leading Order QCD

abstract:
  We present the tree-level amplitudes involving one, two and three photons
that are required for next-to-leading order QCD calculations of production
rates of three final-state particles. We also present the required one-loop
amplitudes in terms of previously published results.


title: Magnetic fields within color superconducting neutron star cores

abstract:
  We discuss the Meissner effect for a color superconductor formed by cold
dense quark matter. Though color and ordinary electromagnetism are broken in a
color superconductor, there is a linear combination of the photon and a gluon
that remains massless. Consequently, a color superconducting region may be
penetrated by an external magnetic field. We show that at most a small fraction
of the magnetic field is expelled, and if the screening distance is the
smallest length scale in the problem there is no expulsion at all. We calculate
the behavior of the magnetic field for a spherical geometry relevant for
compact stars. If a neutron star contains a quark matter core, this core is a
color superconductor. Our results demonstrate that such cores admit magnetic
fields without restricting them to quantized flux tubes. Such magnetic fields
within color superconducting neutron star cores are stable on time scales
longer than the age of the universe, even if the spin period of the neutron
star is changing.


title: Indirect Collider Tests for Large Extra Dimensions

abstract:
  We review the capability of colliders to detect the virtual exchange of
Kaluza-Klein towers of gravitons within the low scale quantum gravity scenario
of Arkani-Hamed, Dimopoulos and Dvali.


title:
Generalized Drell-Hearn-Gerasimov Sum Rule at Order {\cal O}(p^4) in
  Chiral Perturbation Theory

abstract:
  We calculate the forward spin-dependent photon-nucleon Compton amplitudes
$S_1$ and $S_2$ as functions of photon energy $\nu$ and mass $Q^2$ at the
next-to-leading (${\cal O}(p^4)$) order in chiral perturbation theory, from
which we extract the contribution to a generalized Drell-Hearn-Gerasimov sum
rule at low $Q^2$. The result indicates a much rapid $Q^2$ variation of the sum
rule than a simple dimensional analysis would yield.


title: Theoretical status of epsilon'/epsilon

abstract:
  I give a detailed introduction into the theoretical formalism for
epsilon'/epsilon, which measures direct CP-violation in K -> pi pi decays. The
current status of hadronic matrix elements and the strange quark mass is
discussed. Several possible explanations of the unexpectedly high experimental
results for epsilon'/epsilon are pointed out: A small strange quark mass, an
enhancement of the hadronic parameter B_6^(1/2) from the sigma resonance, an
underestimate of isospin breaking and possible new physics contributions in the
sdZ-vertex and the sd-gluon-vertex.


title: Probing the structure of Nucleons in Electromagbetic Interactions

abstract:
  Open problems in the study of the nucleon structure using electromagnetic
probes are discussed. The focus is on experimental aspects in the regime of
strong interaction QCD. Significant progress in our understanding of the
nucleon structure in this domain of QCD may be expected in the first decade of
the next millenium. This is due to major experimental and theoretical efforts
currently underway in this field.


title: Spectra of Baryons Containing Two Heavy Quarks in Potential Model

abstract:
  In this work, we employ the effective vertices for interaction between
diquarks (scalar or axial-vector) and gluon where the form factors are derived
in terms of the B-S equation, to obtain the potential for baryons including a
light quark and a heavy diquark. The concerned phenomenological parameters are
obtained by fitting data of $B^{(*)}-$mesons instead of the heavy quarkonia.
The operator ordering problem in quantum mechanics is discussed. Our numerical
results indicate that the mass splitting between $B_{3/2}(V), B_{1/2}(V)$ and
$B_{1/2}(S)$ is very small and it is consistent with the heavy quark effective
theory (HQET).


title: Is Heavy Baryon Approach Necessary?

abstract:
  It is demonstrated that using an appropriately chosen renormalization
condition one can respect power counting within the relativistic baryon chiral
perturbation theory without appealing to the technique of the heavy baryon
approach. Explicit calculations are performed for diagrams including two-loops.
It is argued that the introduction of the heavy baryon chiral perturbation
theory was useful but not necessary.


title: Neutrino Masses and Mixings with Flavor Symmetries

abstract:
  Recent atmospheric neutrino data at Super-Kamiokande suggest the large flavor
mixing of neutrinos. Models for the lepton mass matrix, which give the
near-maximal flavor mixing, are discussed in the three family model.
Especially, details of the models with the $S_3$ or O(3) flavor symmetry are
studied.


title: Charm production at HERA

abstract:
  The ZEUS data on the charm structure function F_2^c at small x fit well to a
single power of x, corresponding to the exchange of a hard pomeron that is
flavour-blind. When combined with the contribution from the exchange of a soft
pomeron, the hard pomeron gives a good description of elastic $J/\psi$
photoproduction.


title: The $\Delta I=1/2$ rule and other matrix elements

abstract:
  Recent work by J.Prades and myself on $K\to\pi\pi$ is described. The method
we use to consistently connect long and short distances is described and
numerical results for the $\Delta I=1/2$ rule and on $B_6$, the parameter
relevant for the strong part of $\epsilon'/\epsilon$, are given in the chiral
limit.


title:
Complete Set of Splitting Functions Relevant in the Evolution of
  Nucleonic Helicity Distributions

abstract:
  In this work, we show how the complete set of splitting functions relevant
for the evolution of various distribution functions describing nucleonic
helicity structure can be obtained in the light front Hamiltonian perturbation
theory using completely fixed light front gauge, $A^+=0$.


title:
Pseudo-Goldstone Boson Effects in Top-Antitop Productions at High Energy
  Hadron Colliders and Testing Technicolor Models

abstract:
  We study the top quark pair production process p+p(anti-p)-->top+antitop in
various kinds of technicolor (TC) models at the Fermilab Tevatron Run II and
the CERN LHC. The s-channel neutral pseudo-Goldstone bosons (PGB's) contribute
dominately to the production amplitudes from its coupling to the gluons through
the triangle loops of techniquarks and the top quark. Cross sections in
different TC models with s-channel PGB contributions are calculated. It is
shown that the PGB effects can be experimentally tested and different TC models
under consideration can be distinguished at the LHC. Therefore, the
p+p-->top+antitop process at the LHC provides feasible tests of the TC models.


title:
Selected Topics in Light Front Field Theory and Applications to the High
  Energy Phenomena

abstract:
  In this thesis, we have presented some of the aspects of light-front (LF)
field theory through their successful application in the Deep Inelastic
Scattering (DIS). We have developed a LFQCD Hamiltonian description of the DIS
structure functions starting from Bjorken-Johnson-Low limit of virtual forward
Compton scattering amplitude and using LF current commutators. We worked in the
LF gauge $A^+=0$ and used the old-fashioned LFQCD perturbation theory in our
calculations. The importance of our work are summarized below.
  Our approach shares the intution of parton model and addresses directly the
structure functions, which are experimental objects, instead of its moments as
in OPE method. Moreover, it can potentially incorporate the non-perturbative
contents of the structure functions as we have demonstrated by introducing a
new factorization scheme.
  In the context of nucleonic helicity structure, the well known gauge fixed LF
helicity operator is shown to provide consistent physical information and helps
us defining new relevant structure functions. The anomalous dimensions relevant
for the $Q^2$-evolution of such structure functions are calculated.
  Our study is important in establishing the equivalance of LF field theory and
the usual equal-time one through perturbative calculations of the dressed
parton structure functions reproducing the well known results. Also the
importance of Gallilean boost symmetry in understanding the correctness of any
higher order calculation using ($x^+$)-ordered LFQCD perturbation theory are
emphasized.


title: A Direct Reconstruction of the Gaugino Parameters with Phases

abstract:
  A simple algebraic algorithm is described to recover the (complex valued)
gaugino/Higgsino basic parameters $\mu = |\mu| e^{i \phi_\mu}$, $M_1 = |M_1|
e^{i \phi_{M_1}}$, $M_2 = |M_2|$, directly in terms of (a minimal set of)
neutralino and chargino masses, accurately measurable at future linear collider
energies. An ambiguity in the $M_1$ reconstruction can be resolved by measuring
the corresponding $e^+e^- \to \chi^0_1 \chi^0_2$ cross section. This approach
should simplify the determination of allowed ranges of the gaugino parameters,
in particular if only a partial set of gaugino masses were measured.


title:
Charge exchange $\rho^0 \pi^+ $ photoproduction and implications for
  searches of exotic meson

abstract:
  We analyze the process $\vec \gamma +p\to \rho^0 \pi^{+}n$ at low momentum
transfer focusing on a possibility of production of an exotic $J^{PC}=1^{-+}$
meson state. In particular we discuss polarization observables and conclude
that linear photon polarization is instrumental for separating of the exotic
wave.


title: Stop-Stop-Higgs Production at future Linear Collider

abstract:
  In the Minimal Supersymmetric Standard Model, the cross section for the
associated production of the lightest neutral Higgs boson with the lightest top
squark pairs can be rather substantial at high energies. We summarize the
properties of this production process at a future e^+e^- linear collider,
including the $\gamma \gamma$ mode.


title:
Analysis of a three flavor neutrino oscillation fit to recent
  Super-Kamiokande data

abstract:
  We have analyzed the most recent available Super-Kamiokande data in a three
flavor neutrino oscillation model. We have here neglected possible matter
effects and performed a fit to atmospheric and solar Super-Kamiokande data. We
have investigated a large parameter range, where the mixing angles were
restricted to $0 \leq \theta_i \leq \pi/2$, $ i=1,2,3$, and the mass squared
differences were taken to be in the intervals $10^{-11} {\rm eV}^2 \leq \Delta
m^2 \leq 10^{-2} {\rm eV}^2$ and $10^{-4} {\rm eV}^2 \leq \Delta M^2 \leq 10
{\rm eV}^2$. This yielded a best solution characterized by the parameter values
$\theta_1 \simeq 45^\circ$, $\theta_2 \simeq 10^\circ$, $\theta_3 \simeq
45^\circ$, $\Delta m^2 \simeq 4.4 \times 10^{-10} {\rm eV}^2$, and $\Delta M^2
\simeq 1.01 \times 10^{-3} {\rm eV}^2$, which shows that the analyzed
experimental data speak in favor of a bimaximal mixing scenario with one of the
mass squared differences in the ``just-so'' domain and the other one in the
range capable of providing a solution to the atmospheric neutrino problem.


title:
Measuring Higgs Branching Ratios and telling the SM from a MSSM Higgs
  Boson at the e+e- Linear Collider

abstract:
  An accurate determination of the Higgs decay branching ratios to bb, cc, gg,
WW* and tau tau pairs is important for the study of the Higgs couplings and for
determining its SM or MSSM nature in the mass range 100 GeV/c2 < M_H < 140
GeV/c^2. This measurement also represents an important benchmark for the
optimisation of the detector design. The accuracy on the determination of the
Higgs decay branching ratio to fermions and WW* pairs has been studied using
the simulation of the detector designed for the TESLA e+e- linear collider at
c.m. energy of 350 GeV and 500 GeV. The results are discussed in terms of the
ability of discriminating between the SM and a MSSM neutral Higgs boson and of
the predictivity on the A boson mass in the MSSM scenario.


title: Meson-like Baryons and the Spin-Orbit Puzzle

abstract:
  I describe a special class of meson-like \Lambda_Q excited states and present
evidence supporting the similarity of their spin-independent spectra to those
of mesons. I then examine spin-dependent forces in these baryons, showing that
predicted effects of spin-orbit forces are small for them for the same reason
they are small for the analogous mesons: a fortuitous cancellation between
large spin-orbit forces due to one-gluon-exchange and equally large inverted
spin-orbit forces due to Thomas precession in the confining potential. In
addition to eliminating the baryon spin-orbit puzzle in these states, this
solution provides a new perspective on spin-orbit forces in all baryons.


title:
Hadron Electric Dipole Moments from CP-Odd Operators of Dimension Five
  Via QCD Sum Rules: The Vector Meson

abstract:
  We present a complete analysis of the electric dipole moment (EDM) of the
\rho-meson induced by CP violating operators of dimension 4 and 5 within the
QCD sum rules approach. The set of CP-odd operators includes the theta term and
the electric and chromoelectric dipole moments of the three light quarks. We
find that the \rho-meson EDM induced purely by the EDMs of quarks is smaller,
but still in reasonable agreement, with the predictions of a naive constituent
quark model. However, the chromoelectric dipole moments, including that of the
strange quark, give comparable and sometimes larger contributions. We also
consider the effect on the hadronic EDM of the existence of Peccei-Quinn
symmetry. When this symmetry is active, chromoelectric dipole moments induce a
linear term in the axion potential which leads to a numerically important
vacuum contribution to the hadronic EDM.


title: J/psi Production: Tevatron and Fixed-Target Collisions

abstract:
  In this talk I show the results of a fit of the NRQCD matrix elements to the
CDF data for direct $J/\psi$ production, by including the radiative corrections
to the colour-singlet channel and the effect of the $k_T$-smearing. Furthermore
I perform the NLO NRQCD analysis of $J/\psi$ production in fixed-target
proton-nucleon collisions and I fit the colour-octet matrix elements to the
available experimental data. The results are compared to the Tevatron ones.


title: Stop and Sbottom Searches in Run II of the Fermilab Tevatron

abstract:
  We estimate the Tevatron Run II potential for top and bottom squark searches.
We find an impressive reach in several of the possible discovery channels. We
also study some new channels which may arise in non-conventional supersymmetry
models. In each case we rely on a detailed Monte Carlo simulation of the
collider events and the CDF detector performance in Run I.


title: Lifetime of Collective Isospin Rotations of a Quantum Meson Field

abstract:
  We calculate the lifetime of the collective isospin rotating solutions which
have been found recently in the case a quantum N-component meson field with
exact O(N) symmetry. For this purpose we take into account the small breaking
of the O(N) symmetry associated to the non vanishing mass of the pion. This
term induces a coupling between collective rotations and intrinsic meson
excitations. We evaluate the associated damping time in the framework of linear
response theory. We find damping times of the order of 100 fm/c, i.e.
substantially longer than reaction times.


title: Kaluza-Klein Thresholds and Regularization (In)dependence

abstract:
  We present a method to control the regularization scheme dependence in the
running of couplings in Kaluza-Klein theories. Specifically we consider the
scalar theory in five dimensions, assuming that one dimension is compactified
and we study various regularization schemes in order to analyze concretely the
regularization scheme dependence of the Kaluza-Klein threshold effects. We find
that in one-loop order, although the $\beta$-functions are different for the
different schemes, the net difference in the running of the coupling among the
different schemes is very small for the entire range of energies. Our results
have been extended to include more than one radii, and the gauge coupling
unification is re-examined. Strings are also used as a regulator. We obtain a
particular regularization of effective field theory which can accurately
describe the string Kaluza-Klein threshold effects.


title:
Electroweak Sudakov form factors and nonfactorizable soft QED effects at
  NLC energies

abstract:
  We study the leading log infrared behavior of electroweak corrections at TeV
scale energies, that will be reached by next generation of linear colliders
(NLC). We show that, contrary to what happens at typical LEP energies, it is
not anymore possible to disentangle ``pure electroweak'' from ``photonic''
corrections. This means that soft QED effects do not factorize and therefore
cannot be treated in the usual ``naive'' way they were accounted for in the
LEP-era. The nonfactorizable effects come up first at the two loop LL level,
that we calculate explicitly for a fermion source that is neutral under the
SU(2)$\otimes$U(1) gauge group (explicitly, a Z' decay into two fermions). The
basic formalism we set up can be used to calculate LL effects at any order of
perturbation theory. The results of this paper might be important for future
calculations of electroweak corrections at NLC energies.


title:
Quantization and renormalization of the manifest left-right symmetric
  model of electroweak interactions

abstract:
  Quantization and renormalization of the left-right symmetric model is the
main purpose of the paper. First the model at tree level with a Higgs sector
containing one bidoublet and two triplets is precisely discussed. Then the
canonical quantization and Faddeev-Popov Lagrangian are carried out ('t Hooft
gauge). The BRST symmetry is discussed. Subsequently the on mass shell
renormalization is performed and, as a test of consistency, the renormalization
of the ZNiNj vertex is analyzed.


title: Event Generation of Large-Angle Bhabha Scattering at LEP2 Energies

abstract:
  LABSMC Monte Carlo event generator is used to simulate Bhabha scattering at
high energies. Different sources of radiative corrections are considered. The
resulting precision is discussed.


title:
$\cal CPT$-invariant two-fermion Dirac equation with extended hyperfine
  operator

abstract:
  For the S-states of muonium and positronium, the hyperfine shifts to the
order $\alpha^6$ of a recently derived two-fermion equation with explicit $\cal
CPT$-invariance are checked against the results of a nonrelativistic reduction,
and the leading $\alpha^8$ shifts are calculated. An additional hyperfine
operator is discovered which can milden the singularity for $r\to 0$ of the
Dirac hyperfine operator, such that the resulting extended operator can be used
nonperturbatively. The binding correction to magnetic moments is mentioned.


title: Hyperon semileptonic decays and quark spin content of the proton

abstract:
  We investigate the hyperon semileptonic decays and the quark spin content of
the proton $\Delta \Sigma$ taking into account flavor SU(3) symmetry breaking.
Symmetry breaking is implemented with the help of the chiral quark-soliton
model in an approach, in which the dynamical parameters are fixed by the
experimental data for six hyperon semileptonic decay constants. As a result we
predict the unmeasured decay constants, particularly for $\Xi^0 \to \Sigma^+$,
which will be soon measured and examine the effect of the SU(3) symmetry
breaking on the spin content $\Delta \Sigma $ of the proton. Unfortunately
large experimental errors of $\Xi^-$ decays propagate in our analysis making
$\Delta \Sigma$ and $\Delta s$ practically undetermined. We conclude that
statements concerning the values of these two quantities, which are based on
the exact SU(3) symmetry, are premature. We stress that the meaningful results
can be obtained only if the experimental errors for the $\Xi$ decays are
reduced.


title: Precise Calculations for the Neutral Higgs-Boson Masses in the MSSM

abstract:
  We review the comparison of the results for the neutral CP-even Higgs-boson
masses recently obtained within the Feynman-diagrammatic approach with the
previous results based on the renormalization group approach. We show that the
results differ by new genuine two-loop contributions present in the
Feynman-diagrammatic calculation. The numerical effect of these terms on the
result for m_h is briefly discussed.


title:
The diagonal spin basis and calculation of processes involving polarized
  particles

abstract:
  The review of developed by the authors new techniques for covariant
calculation of matrix elements in QED, the so-called formalism of "Diagonal
Spin Basis" (DSB), is presented. In DSB spin 4-vectors of in- and out- fermions
are expressed just in terms of their 4-momenta. In this approach the little
Lorentz group, common for the initial and final states,is realized. This brings
the spin operators of in- and out-particles to coincidence. The developed
approach is valid both for massive fermions and for massless ones. There occur
no problems with accounting for spin flip amplitudes in it. Just 4-momenta of
particles participating in reactions are required in it to construct the
mathematical apparatus for calculations of matrix elements. We apply this
formalism to the next processes: 1) M\"oller and Bhabha bremsstrahlung
($e^{\pm}e^- \to e^{\pm}e^- \gamma$) in the ultrarelativistic limit when
initial particles and photon are helicity polarized; 2) Compton back-scattering
of photons of intensive circularly polarized laser wave on a beam of
longitudinally polarized ultrarelativistic electrons ($e+n\gamma_0 \to e+\gamma
$); 3) $e^+e^-$-pair production by a hard photon in simultaneous collision with
several laser beam photons ($\gamma+n \gamma_0 \to e^+ + e^-$); 4)
Bethe-Heitler process in the case of a linearly polarized photon emission by an
electron with account for proton recoil and form factors; 5) the reaction $ep
\to ep \gamma$ with proton polarizability being taken into account in the
kinematics when proton bremsstrahlung dominates; 6) orthopositronium 3-photon
annihilation ($e^+e^{-} \to 3 \gamma$).


title: Few-Body States in Lund String Fragmentation Model

abstract:
  The well-known Monte Carlo simulation packet JETSET is not built in order to
describe few-body states (in particular at the few GeV level in e^+e^-
annihilation as in BEPC). In this note we will develop the formalism to use the
basic Lund Model area law directly for Monte Carlo simulations


title: Earth Matter Effect in 7Be Solar Neutrino Experiments

abstract:
  We determine the sensitivity of the KamLAND and Borexino experiments to the
neutrino regeneration effect in the Earth as a function of Delta m^2 and theta,
using realistic numbers for the signal and background rates. We compare the
results obtained with the chi^2 method with those obtained from the
conventional day-night asymmetry analysis. We also investigate how well one
should be able to measure the neutrino oscillation parameters if a large
day-night asymmetry is observed, taking the LOW solution as an example. We
present an enlarged parameter space, which contains mixing angles greater than
pi/4 where the heavy mass eigenstate is predominantly nu_e, and determine the
electron neutrino survival probability for this traditionally neglected
scenario. We emphasize that this portion of the parameter space yields
different physics results when dealing with the MSW solutions to the solar
neutrino puzzle and should not be neglected.


title: Charged and Pseudoscalar Higgs production at a Muon Collider

abstract:
  We consider single charged Higgs ($H^{\pm}$) and pseudoscalar Higgs ($A^0$)
production in association with a gauge boson at $\mu^+\mu^-$ colliders. We find
that the tree-level t-channel and s-channel contributions to $\mu^+\mu^-\to
H^{\pm}W^{\mp}, A^0Z$ are enhanced for large values of $\tan\beta$, allowing
sizeable cross-sections whose analogies at $e^+e^-$ colliders would be very
small. These processes provide attractive new ways of producing such particles
at $\mu^+\mu^-$ colliders and are superior to the conventional methods in
regions of parameter space.


title: QCD Interconnection Effects

abstract:
  Heavy objects like the W, Z and t are short-lived compared with typical
hadronization times. When pairs of such particles are produced, the subsequent
hadronic decay systems may therefore become interconnected. We study such
potential effects at Linear Collider energies.


title: Derivation of the Gasser-Leutwyler Lagrangian from QCD

abstract:
  The normal part of the Gasser-Leutwyler formulation of the chiral Lagrangian
is formally derived from the first principles of QCD without taking
approximations. All the coefficients are expressed in terms of certain Green's
functions in QCD, which can be regarded as the general QCD definitions of the
normal part of the coefficients. The approximate values of the coefficients are
also presented.


title:
Classical String Solutions in Effective Infrared Theory of SU(3)
  Gluodynamics

abstract:
  We investigate string solutions to the classical equations of motion
("classical QCD strings") for a dual Ginzburg-Landau model corresponding to
SU(3) gluodynamics in an abelian projection. For a certain relation between
couplings of the model the string solutions are defined by first order
differential equations. These solutions are related to vortex configurations of
the Abelian Higgs model in the Bogomol'ny limit. An analytic expression for the
string tension is derived and the string-string interactions are discussed. Our
results imply that the vacuum of SU(3) gluodynamics is near a border between
type-I and type-II dual superconductivity.


title: Implications of Recent Measurements of Hadronic Charmless B Decays

abstract:
  Implications of recent CLEO measurements of hadronic charmless B decays are
discussed. (i) Employing the Bauer-Stech-Wirbel (BSW) model for form factors as
a benchmark, the $B\to\pi^+\pi^-$ data indicate that the form factor
$F_0^{B\pi}(0)$ is smaller than that predicted by the BSW model, whereas the
data of $B\to\omega\pi, K^*\eta$ imply that the form factors $A_0^{B\omega}(0),
A_0^{BK^*}(0)$ are greater than the BSW model's values. (ii) The tree-dominated
modes $B\to\pi^+\pi^-, \rho^0\pi^\pm, \omega\pi^\pm$ imply that the effective
number of colors N_c(LL) for (V-A)(V-A) operators is preferred to be smaller,
while the current limit on $B\to\phi K$ shows that N_c(LR)>3. The data of $B\to
K\eta'$ and $K^*\eta$ clearly indicate that $N_c(LR)\gg N_c(LL)$. (iii) In
order to understand the observed suppression of $\pi^+\pi^-$ and
non-suppression of $K\pi$ modes, both being governed by the form factor
$F_0^{B\pi}$, the unitarity angle $\gamma$ is preferred to be greater than
$90^\circ$. By contrast, the new measurement of $B^\pm\to\rho^0\pi^\pm$ no
longer strongly favors $\cos\gamma<0$. (iv) The observed pattern $K^-\pi^+\sim
\ov K^0\pi^-\sim {2\over 3}K^-\pi^0$ is consistent with the theoretical
expectation: The constructive interference between electroweak and QCD penguin
diagrams in the $K^-\pi^0$ mode explains why ${\cal B}(B^-\to K^-\pi^0)>{1\over
2}{\cal B}(\ov B^0\to K^-\pi^+)$. (v) The observation $\nc(LL)<3<\nc(LR)$ and
our preference for $\nc(LL)\sim 2$ and $\nc(LR)\sim 6$ are justified by a
recent perturbative QCD calculation of hadronic rare B decays in the heavy
quark limit.


title: Techniques for QCD calculations by numerical integration

abstract:
  Calculations of observables in quantum chromodynamics are typically performed
using a method that combines numerical integrations over the momenta of final
state particles with analytical integrations over the momenta of virtual
particles. I describe the most important steps of a method for performing all
of the integrations numerically.


title:
Study of e^{+}e^{-} --> \tilde{\chi}^{+}_{1} \tilde{\chi}^{-}_{1} -->
  \tilde{\tau}^{+}_{1}\nu_{\tau} + \tilde{\tau}^{-}_{1}\bar{\nu}_{\tau}

abstract:
  In Supersymmetry with large $\tan\beta$ values, the lighter stau
($\tilde{\tau}_{1}$) may be lighter than the lightest chargino
($\tilde{\chi}^{\pm}_{1}$). The decay $\tilde{\chi}^{\pm}_{1} \to
\tilde{\tau}^{\pm}_{1} \nu_{\tau}$, followed by $\tilde{\tau}^{\pm}_{1} \to
\tilde{\chi}^{0}_{1} \tau$, alters a phenomenology of the chargino production.
We study the chargino pair production at future $e^{+}e^{-}$ linear colliders.


title: Parton distributions, form factors and Compton scattering

abstract:
  The soft physics approach to form factors and Compton scattering at
moderately large momentum transfer is reviewed. It will be argued that in that
approach the Compton cross section is given by the Klein-Nishina cross section
multiplied by a factor describing the structure of the proton in terms of two
new form factors. These form factors as well as the ordinary electromagnetic
form factors represent moments of skewed parton distributions.


title:
A Random Matrix Model for Color Superconductivity at Zero Chemical
  Potential

abstract:
  We discuss random matrix models for the spontaneous breaking of both chiral
and color symmetries at zero chemical potential and finite temperature.
Exploring different Lorentz and gauge symmetric color structures of the random
matrix interactions, we find that spontaneous chiral symmetry breaking is
always thermodynamically preferred over diquark condensation. Stable diquark
condensates appear only as SU(2) rotated chiral condensates, which do not
represent an independent thermodynamic phase. Our analysis is based on general
symmetry arguments and hence suggests that no stable and independent diquark
phase can form in QCD with two flavors at zero quark chemical potential.


title: Tevatron Signatures of an R-parity Violating Supersymmetric Theory

abstract:
  We show that an R-parity violating supersymmetric scenario which can account
for the atmospheric nu(mu) deficit has testable signals at the Fermilab
Tevatron with upgraded energy and luminosity. The explanation of neutrino
masses and maximal nu(mu)-nu(tau) oscillation in terms of bilinear R-violating
terms in the superpotential associates comparable numbers of muons and tau's
resulting from decays of the lightest neutralino. We show that this should lead
to like-sign dimuons and ditaus with substantial rates, in a form that
separates them from standard model backgrounds and other signals of
supersymmetry. One here also has the possibility of completely reconstructing
the lightest neutralino.


title:
Improvements to the Method of Dispersion Relations for B Nonleptonic
  Decays

abstract:
  We bring some clarifications and improvements to the method of dispersion
relations in the external masses variables, that we proposed recently for
investigating the final state interactions in the B nonleptonic decays. We
first present arguments for the existence of an additional term in the
dispersion representation, which arises from an equal-time commutator in the
LSZ formalism and can be approximated by the conventional factorized amplitude.
The reality properties of the spectral function and the Goldberger-Treiman
procedure to perform the hadronic unitarity sum are analyzed in more detail. We
also improve the treatment of the strong interaction part by including the
contributions of both t and u-channel trajectories in the Regge amplitudes.
Applications to the $B^0\to \pi^+\pi^-$ and $B^+\to \pi^0 K^+$ decays are
presented.


title: Signature of exotic particles in light by light scattering

abstract:
  We discuss the implications on light by light scattering of two kind of
exotic particles: doubly charged scalar bosons and doubly charged fermions; the
virtual effects of a nonstandard singly charged gauge boson are also examined.
These particles, if their masses lie in the range 0.1--1.0 TeV, will have a
clear signature in the future linear colliders. The present analysis has the
advantage that it depends only on electromagnetic symmetry, so it is applicable
to any model which predicts this class of particles. In particular, our results
have interesting consequences on left-right models and their supersymmetric
extension.


title:
Minding one's P's and Q's : from the one loop effective action in
  quantum field theory to classical transport theory

abstract:
  The one loop effective action in quantum field theory can be expressed as a
quantum mechanical path integral over world lines, with internal symmetries
represented by Grassmanian variables. In this paper, we develop a real time,
many body, world line formalism for the one loop effective action. In
particular, we study hot QCD and obtain the classical transport equations
which, as Litim and Manuel have shown, reduce in the appropriate limit to the
non-Abelian Boltzmann-Langevin equation first obtained by B\"{o}deker. In the
Vlasov limit, the classical kinetic equations are those that correspond to the
hard thermal loop effective action. We also discuss the imaginary time world
line formalism for a hot $\phi^4$ theory, and elucidate its relation to
classical transport theory.


title: Diagnosis of QGP with Strange Hadrons

abstract:
  We review the current status of strangeness as signature of the formation and
dissociation of the deconfined QGP at the SPS energy scale, and present the
status of our considerations for RHIC energies. By analyzing, within the
framework of a Fermi statistical model, the hadron abundance and spectra, the
properties of a disintegrating, hadron evaporating, deconfined QGP fireball are
determined and can be compared with theory for the energy range 160--200AGeV on
fixed target. We discuss in more detail our finding that the pion yields occur
near to pion condensation condition. Dynamical models of chemical strangeness
equilibration are developed and applied to obtain strangeness production in a
QGP phase at conditions found at SPS and expected at RHIC.
  The sudden QGP break up model that works for the SPS data implies at RHIC
dominance of both baryon, and antibaryon, abundances by the strange baryon and
antibaryon yields.


title: Top-Higgs Yukawa Coupling Measurement at a Linear e+e- Collider

abstract:
  A feasibility study of the measurement of the top-Higgs Yukawa coupling at a
future linear e+e- collider operating at sqrt(s)=800 GeV is presented. As
compared to previous existing studies, much effort has been put in a
``realistic simulation'' by including irreducible+reducible backgrounds,
realistic detector effects and reconstruction procedures and finally, a
multivariate analysis. Both hadronic and semileptonic decay channels have been
considered.


title: Gauging the Shadow Sector with SO(3)

abstract:
  We examine the phenomenology of a low-energy extension of the Standard Model,
based on the gauge group SU(3) x SU(2) x U(1) x SO(3), with SO(3) operating in
the shadow sector. This model offers $\nu_{e} \to \nu_{s}$ and $\nu_{\mu} \to
\nu_{\tau}$ oscillations as the solution of the solar and atmospheric neutrino
problems. Moreover, it provides a neutral heavy shadow lepton X that could play
the role of a cold dark matter particle.


title: Topcolor-Assisted Supersymmetry

abstract:
  It has been known that the supersymmetric flavor changing neutral current
problem can be avoided if the squarks take the following mass pattern, namely
the first two generations with the same chirality are degenerate with masses
around the weak scale, while the third generation is very heavy. We realize
this scenario through the supersymmetric extension of a topcolor model with
gauge mediated supersymmetry breaking.


title:
pi^0 pi^0 Scattering Amplitudes and Phase Shifts Obtained by the pi^- P
  Charge Exchange Process

abstract:
  The results of the analysis of the pi^0 pi^0 scattering amplitudes obtained
with pi^- P charge exchange reaction, pi^- P --> pi^0 pi^0 n, data at 9 GeV/c
are presented. The pi^0 pi^0 scattering amplitudes show clear f_0(1370) and
f_2(1270) signals in the S and D waves, respectively. The pi^0 pi^0 scattering
phase shifts have been obtained below Kbar K threshold and been analyzed by the
Interfering Amplitude method with introduction of negative background phases.
The results show a S wave resonance, sigma. Its Breit-Wigner parameters are in
good agreement with those of our previous analysis on the pi^+ pi^- phase shift
data.


title:
Structure of Chiral Phase Transitions at Finite Temperature in Abelian
  Gauge Theories

abstract:
  The mechanism of the chiral symmetry breaking is investigated in the
strong-coupling Abelian gauge theories at finite temperature. The
Schwinger-Dyson equation in Landau gauge is employed in the real time formalism
and is solved numerically within the framework of the instantaneous exchange
approximation including the effect of the hard thermal loop for the photon
propagator. It is found that the chiral symmetry is broken below the critical
temperature T for sufficiently large coupling. The chiral phase transition is
found to be of the 2nd order and the phase diagram on the $T-\alpha$ plane is
obtained. It is investigated how the structure of the chiral phase transition
is affected by the hard thermal loops in the photon propagator.