title: Differential Renormalization of Gauge Theories

abstract:
  The scope of constrained differential renormalization is to provide
renormalized expressions for Feynman graphs, preserving at the same time the
Ward identities of the theory. It has been shown recently that this can be done
consistently at least to one loop for abelian and non-abelian gauge theories.
We briefly review these results, evaluate as an example the gluon selfenergy in
both coordinate and momentum space, and comment on anomalies.


title:
Testing Technicolor Models via Top Quark Pair Production in High Energy
  Photon Collisions

abstract:
  Pseudo-Goldstone boson contributions to $t\bar{t}$ production rates in
technicolor models with and without topcolor at the $\sqrt{s}=0.5 and 1.5$ TeV
photon colliders and hadron colliders are reviewed. For reasonable ranges of
the parameters, the contributions are large enough to be experimentally
observable. Models with topcolor, without topcolor and the MSSM with
$\tan\beta\geq 1$ can be experimentally distinguished.


title: Radiative corrections to $e^+ e^- \to H^+ H^-$: THDM versus MSSM

abstract:
  One loop radiative corrections to $e^+e^-\to H^+ H^-$ are considered at
future linear collider energies, in the general type II Two Higgs Doublet Model
(THDM) and in the Minimal Supersymmetric Standard Model-like (MSSM) Higgs
sector. To make the comparison between THDM and MSSM tractable, we have
introduced a quasi-SUSY parameterization which preserves all the tree-level
Higgs mass-sum-rules of the MSSM, and involves just 3 free parameters in the
Higgs sector (instead of 7 in the general THDM) and comprises the MSSM as a
particular case. The model-independent soft photon contribution is isolated and
shown to be substantial. Important effects come also from the contribution of
the model dependent $h^0 H^+ H^-$ and $H^0 H^+ H^-$ vertices to the final
state. In the MSSM, the contribution of the Higgs sector is moderate (a few
percent) while in the THDM and both for small and large $\tan \beta$ important
effects ($\sim +30%$) can be found.


title: Phenomenological Bounds on B to Light Semileptonic Form Factors

abstract:
  The form factors for the weak currents between B and light mesons are studied
by relating them to the corresponding D form factors at q^2_{max} according to
HQET, by evaluating them at q^2=0 by QCD sum rules, and by assuming a polar q^2
dependence. The results found are consistent with the information obtained from
exclusive non-leptonic two-body decays and, with the only exception of A_1,
with lattice calculations.


title: Solar Magnetic Field Profiles and SuperKamiokande Data

abstract:
  The distortion of the energy spectrum of recoil electrons in SuperKamiokande
resulting from several solar magnetic field profiles that are consistent with
data and standard solar models is investigated. The aim is to provide a test of
the general common features of these field profiles derived in a previous work
on the basis of the resonant spin flip flavour mechanism. It is found that the
distortion may be visible in the data, becoming possibly clearer when the
energy threshold succeeds in being reduced and distinct from the ones resulting
from oscillations.


title:
Differential cross sections for high energy elastic hadron-hadron
  scattering in nonperturbative QCD

abstract:
  Total and differential cross sections for high energy and small momentum
transfer elastic hadron-hadron scattering are studied in QCD using a functional
integral approach. The hadronic amplitudes are governed by vacuum expectation
values of lightlike Wegner-Wilson loops, for which a matrix cumulant expansion
is derived. The cumulants are evaluated within the framework of the Minkowskian
version of the model of the stochastic vacuum. Using the second cumulant, we
calculate elastic differential cross sections for hadron-hadron scattering. The
agreement with experimental data is good.


title:
Units and Numerical Values of the Effective Couplings in Perturbative
  Heterotic String Vacua

abstract:
  We determine the units and numerical values for a class of couplings in the
effective theory of perturbative heterotic string vacua, with the emphasis on
the correct translation between the canonical gauge coupling g and Planck scale
M_Planck ~ 1.2 x 10^19 GeV as used in the effective theory description and the
string coupling g_string and string tension alpha' as used in the S-matrix
amplitude calculation. In particular, we determine the effective couplings in
the superpotential and revisit the Fayet-Iliopoulos (FI) term in a class of
models with an anomalous U(1). We derive the values of the effective Yukawa
couplings (at the third and fourth order) after the restabilization of vacuum
along a particular F- and D-flat direction and show that they are comparable in
magnitude. The result corrects results quoted in the literature, and may have
implications for the string derived phenomenology, e.g., that of fermion
textures.


title: Chiral Perturbation Theory for |Delta I|=3/2 Hyperon Decays

abstract:
  We study the |Delta I|=3/2 amplitudes of hyperon non-leptonic decays of the
form B->B'+pi in the context of chiral perturbation theory. The lowest-order
predictions are determined in terms of only one unknown parameter and are
consistent within errors with current data. We investigate the theoretical
uncertainty of these predictions by calculating the leading non-analytic
corrections. We also present an estimate for the size of the S-wave Lambda and
Cascade decays which vanish at leading order. We find that the corrections to
the lowest-order predictions are within the expectations of naive power
counting and, therefore, that this picture can be tested more accurately with
improved measurements.


title: Superheavy Dark Matter

abstract:
  If there exist fields of mass of the order of $10^{13}$ GeV and large field
inflation occurs, their interaction with classical gravitation will generate
enough particles to give the universe critical density today regardless of
their nongravitational coupling. This is mainly a summary of the work
hep-ph/9802238.


title:
Extremely High Energy Neutrinos, Neutrino Hot Dark Matter, and the
  Highest Energy Cosmic Rays

abstract:
  Extremely high energy (up to 10**(22) eV) cosmic neutrino beams initiate high
energy particle cascades in the background of relic neutrinos from the Big
Bang. We perform numerical calculations to show that such cascades could
contribute more than 10% to the observed cosmic ray flux above 10**(19) eV if
neutrinos have masses in the electron volt range. The required intensity of
primary neutrinos could be consistent with astrophysical models for their
production if the maximum neutrino energy reaches to 10**(22) eV and the
massive neutrino dark matter is locally clustered. Future observations of ultra
high energy cosmic rays will lead to an indirect but practical search for
neutrino dark matter.


title:
$\bf D_s$-- mesons inclusive hadroproduction in the Quark -- Gluon
  String Model

abstract:
  The hadroproduction of $D_s$ mesons is discussed within the framework of the
modified Quark-Gluon String model (QGSM) taking into account the decays of
corresponding $S$--wave resonances. A description of the existing experimental
data on inclusive spectra of $D_s$ - mesons production in $\pi p$ - collision
and asymmetry of leading ($D_s^-$) and nonleading ($D_s^+$) mesons in $\Sigma^-
p$-- interaction is obtained. The predictions for cross sections and
leading/nonleading asymmetry in $\pi p$ - and $\Sigma^- p$-- collision for
different initial momenta are also given.


title:
Numerical analysis of formation and evolution of global strings in 2+1
  dimensions

abstract:
  We simulate the formation and the evolution of global strings taking into
account the expansion of the universe and the concomitant change of the
effective potential, that is, the change from the restoration stage of the
global {\it U}(1)-symmetry to the broken stage. Starting from the thermal
equilibrium state, we run simulations for 100 sets of different initial
conditions in 2+1 dimensions. As a result, we find deviation from scale
invariance. This is because the energy loss mechanism is pair annihilation
rather than intercommutation, so that a string and an anti-string attract each
other under a logarithmic potential.


title: Only Three

abstract:
  It is shown that it is possible to account for all experimental indications
for neutrino oscillations with just three flavours. In particular we suggest
that the atmospheric neutrino anomaly and the LSND result can be explained by
the same mass difference and mixing. Possible implications and future tests of
the resulting mass and mixing pattern are given.


title: Delta M_K and epsilon_K in SUSY at the Next-to-Leading order

abstract:
  We perform a Next-to-Leading order analysis of Delta S=2 processes beyond the
Standard Model. Combining the recently computed NLO anomalous dimensions and
the B parameters of the most general Delta S=2 effective Hamiltonian, we give
an analytic formula for Delta M_K and epsilon_K in terms of the Wilson
coefficients at the high energy scale. This expression can be used for any
extension of the Standard Model with new heavy particles. Using this result, we
consider gluino-mediated contributions to Delta S=2 transitions in general SUSY
models and provide an improved analysis of the constraints on off-diagonal mass
terms between the first two generations of down-type squarks. Finally, we
improve the constraints on R-violating couplings from Delta M_K and epsilon_K.


title: Charmless Nonleptonic Two-Body B Decays in the Factorization Approach

abstract:
  We calculate the two-body nonleptonic B decays using the factorization
method. The recent measured decays by CLEO Collaboration can be explained in
the factorization approach. We propose a number of ratios of branching ratios
to determine the effective coefficients and the form factors.


title: Nuclear Quark and Gluon Distributions in Coordinate Space

abstract:
  In coordinate space, quark and gluon distributions of the nucleon are defined
as correlation functions involving two field operators separated by a
light-cone distance $y^+ = 2l$. We study the nuclear modifications of these
distributions. The largest effect is a strong depletion of parton distributions
(shadowing) at large longitudinal distances, which starts for all parton
species at $l=2$ fm, i.e. at the average nucleon-nucleon separation in nuclei.
On the other hand, the nuclear radius does not play a significant role. At $l
\lsim 1$ fm, nuclear modifications of parton distributions are small. The
intrinsic structure of individual nucleons is evidently not very much affected
by nuclear binding. In particular, there is no evidence for a significant
increase of the quark or gluon correlation length in bound nucleons.


title: An apprach to generate large and small leptonic mixing angles

abstract:
  We take up the point of view that Yukawa couplings can be either 0 or 1, and
the mass patterns of fermions are generated purely from the structure of the
Yukawa matrices. We utilize such neutrino as well as charged leptonic textures
which lead to (maximal) mixing angles of $\pi/4$ in each sector for relevant
transitions. The combined leptonic CKM mixing angles are $\pi/4 \pm \pi/4$
which lead to very small $\sin^2 2 \Theta$ relevant to solar neutrino and LSND
experiments. We propose that on the other hand the absence of the charged
leptonic partner of the sterile neutrino maintains the angle $\pi/4$ from the
neutrino sector for the transition $\nu_\mu \leftrightarrow \nu_s$ and hence
atmospheric neutrino anomaly is explained through maximal mixing.


title: Real time simulations of high energy nuclear collisions

abstract:
  We discuss real time simulations of high energy nuclear collisions in a
classical effective theory of QCD at small x. At high transverse momenta, our
results match the lowest order predictions of pQCD based mini-jet calculations.
We discuss novel non-perturbative behaviour of the small x modes seen at small
transverse momenta.


title: Textures for Atmospheric and Solar Neutrino Oscillations

abstract:
  In theories with three light neutrinos, a complete list of five zeroth-order
textures for lepton mass matrices is found, which naturally yield: m_e =
m_mu=0, m_tau \neq 0, Delta m^2_sun = 0, together with theta_{e tau} = 0,
theta_{mu tau} approx 1. These textures provide suitable starting points for
constructing theories which account for both atmospheric and solar neutrino
fluxes. Using flavor symmetries, two schemes for such lepton masses are found,
and example constructions exhibited.


title: Quantum decoherence effect and neutrino oscillation

abstract:
  In the view of the quantum dynamic theory of measurement developed from the
Hepp-Colemen (HC) model (K. Hepp, Hev.Phys.Acta, {\bf 45}, 237 (1972)), the
quantum decoherence in neutrino flavor oscillation caused by an environment
surrounding neutrinos is generally considered in this paper. The Ellis,
Hagelin, Nanopoulos and Srednicki (EHNS) mechanism for solving the solar
neutrino problem can be comprehended in a framework of the ordinary quantum
mechanics. In the weak- coupling limit, a microscopic model is proposed to
describe the transition of two neutrino system from a pure state to a mixed
state. It gives the modified formula of survival probability of neutrino
oscillation with two additional time-dependent parameters. For specified
environments, this result shows that the oscillating phenomena of neutrino
still exist even without a mass difference in free neutrino.


title: Positivity constraints in QCD

abstract:
  The density matrix positivity is a natural counterpart of unitarity. The
resulting constraints for various parton distribution and correlations are
considered. Their compatibility with leading order QCD evolution is guaranteed
by the probabilistic interpretation of the latter. In the case of non-forward
distributions the positivity constraints naturally imply the symmetric form of
the evolution equation.


title: On the evolution of abelian-Higgs string networks

abstract:
  We study the evolution of abelian-Higgs string networks in numerical
simulations. These are compared against a modified velocity-dependent one scale
model for cosmic string network evolution. This incorporates the contributions
of loop production, massive radiation and friction to the energy loss processes
that are required for scaling evolution. We find that the loop distribution
statistics in the simulations are consistent with the long-time scaling of the
network being dominated by loop production. For an oscillating sinusoidal
perturbation, we also demonstrate that the power emitted into massive radiation
decays strongly with wavelength. Putting these observations together and
extrapolating, we believe there is insufficient evidence to reject the the
standard picture of string network evolution in favour of one where direct
massive radiation is the dominant decay mechanism, a proposal which has
attracted much recent interest.


title:
Effect of spatial fluctuations on the scaled factorial moments in
  second-order quark-hadron phase transition within Ginzburg-Landau description

abstract:
  The scaled factorial moments in second-order quark-hadron phase transition
are reexamined within the Ginzburg-Landau description, with the spatial
fluctuations of phase angle of the complex field $\phi$ taken into account
rigorously. Scaling behaviors between $F_q$ and $F_2$ are shown, and the
exponent $\nu$ is found very close to the one without spatial fluctuations.


title:
Critical basis dependence in bounding R-parity breaking couplings from
  neutral meson mixing

abstract:
  Assuming one nonzero product of two $\lambda'$-type couplings and working in
two different bases for the left-handed quark superfields, the neutral meson
mixings are used to bound these products. We emphasize the strong basis
dependence of the bounds: in one basis many products contribute to neutral
meson mixings at tree level, while in the other these products except one
contribute at 1-loop level only and the GIM mechanism takes place.
Correspondingly, these bounds differ between bases by orders of magnitudes.


title: Skeletons and Variation

abstract:
  Well known from the sixties, the pressure of e.g. massless phi-four theory
may be written as a series of 2PI-diagrams (skeletons) with the lines fully
dressed. Varying the self-energy Pi in this expression, it turns into a
functional U[Y] having a maximum in function space at Y=Pi. There is also the
Feynman-Jensen thermal variational principle V[S], a potentially
non-perturbative tool. Here actions S are varied.
  It is shown, through a few formal but exact steps, that the functional U is
covered by V. The corresponding special subset of trial actions is made
explicit.


title:
On the 2nd Order Corrections to the Hard Pomeron and the Running
  Coupling Constant

abstract:
  It is shown that solutions to the 2nd order BFKL eigenvalue equation exist
for arbitrary large real values of the complex angular momentum $j$. This
corresponds to a cut in the complex $j$ plane along the whole real axis, and it
makes the use of the complex angular momentum variable for the calculation of
the high-energy behavior somewhat questionable. The eigenfunctions contain
non-perturbative pieces which behave as $\exp(-1/\alpha_s b)$ and have no
counterpart in the leading-log BFKL equation. The high-energy behavior of the
2nd order BFKL Green function as found by other authors, is reproduced by
excluding these non-perturbative pieces of the eigenfunctions.


title:
Radiative symmetry breaking and the ${b \to s \gamma}$ decay in
  generalized GMSB models

abstract:
  We study a class of generalized models of gauge mediated supersymmetry
breaking (GMSB). We find the parameters and the full particle spectrum of the
minimal supersymmetric standard model (MSSM) for all GMSB models with messenger
multiplicities that satisfy the perturbativity of the gauge couplings up to the
GUT scale. We give a detailed description of the algorithm that has been used
to predict all the unmeasured parameters of the MSSM by taking (one-loop)
radiative effects into account. We also calculate the branching ratio $BR(b \to
s \gamma)$ and find that it always turns out to be larger than the standard
model prediction. However, we find that the branching ratio typically remains
within the current experimental bounds, except for some special cases with a
light charged Higgs boson, or a small supersymmetry breaking scale and a
negative $\mu$-parameter.


title:
Neutrino conversions in random magnetic fields and $\tilde{\nu}_e$ from
  the Sun

abstract:
  The magnetic field in the convective zone of the Sun has a random small-scale
component with the r.m.s. value substantially exceeding the strength of a
regular large-scale field. For two Majorana neutrino flavors $\times$ two
helicities in the presence of a neutrino transition magnetic moment and nonzero
neutrino mixing we analyze the displacement of the allowed ($\Delta m^2-
\sin^22\theta$)-parameter region reconciled for the SuperKamiokande(SK) and
radiochemical (GALLEX, SAGE, Homestake) experiments in dependence on the r.m.s.
magnetic field value $b$, or more precisely, on a value $\mu b$ assuming the
transition magnetic moment $\mu = 10^{-11}\mu_B$. In contrast to RSFP in
regular magnetic fields we find an effective production of electron
antineutrinos in the Sun even for small neutrino mixing through cascade
conversions $\nu_{eL}\to \nu_{\mu L}\to \tilde{\nu}_{eR}$, $\nu_{eL}\to
\nu_{\mu R}\to \tilde{\nu}_{eR}$ in a random magnetic field that would be a
signature of the Majorana nature of neutrino if $\tilde{\nu}_{eR}$ will be
registered. Basing on the present SK bound on electron antineutrinos we have
also found an excluded area in the same $\Delta m^2,~\sin^22\theta$-plane and
revealed a strong sensitivity to the random magnetic field correlation length
$L_0$.


title: Evidence for "sterile neutrino" dark matter?

abstract:
  I show that it may be possible to explain the present evidence for a
gamma-ray emission from the galactic halo as due to halo WIMP annihilations.
Not only the intensity and spatial pattern of the halo emission can be matched
but also the relic density of the candidate WIMP can be in the cosmologically
interesting domain. After a model-independent analysis to learn about the
properties of a suitable candidate, I present a working model: a sterile
neutrino in a model with an extended Higgs sector. Two examples indicate the
existence of an interesting region in the model parameter space where present
observational and experimental constraints are satisfied and the gamma-ray
emission is reproduced.


title: Hot QED beyond ladder graphs

abstract:
  At finite temperature a breakdown of the hard thermal loop expansion arises
whenever external momenta are light-like or tend to very soft scales. A
resummation of ladder graphs is important in these cases where the effects of
infrared or light-cone singularities are enhanced. We show that in hot QED
another class of diagrams is also relevant at leading order due to long range
magnetic interactions and therefore recent studies about ladder expansions need
to be corrected. A general cancellation of the hard modes damping effects still
occurs near the light-cone or in the infrared region. The validity of an
improved version of the hard thermal loop resummation scheme is discussed.


title: Anomaly Matching and Syzygies in N=1 Gauge Theories

abstract:
  We investigate the connection between the moduli space of N=1 supersymmetric
gauge theories and the set of polynomial gauge invariants constrained by
classical/quantum relations called syzygies. We examine the existence of a
superpotential reproducing these syzygies and the link with the 't Hooft
anomaly matching between the fundamental fields at high energy and the gauge
invariant degrees of freedom at low energy for the flavour symmetry group. We
show that the anomaly matching is equivalent to the vanishing of the flavour
anomaly on the normal space to the manifold defined by the syzygies. For normal
spaces in a real representation of the flavour group we strengthen the
connection between the 't Hooft anomaly matching and the existence of a
superpotential by constructing a flavour invariant polynomial whose gradient
vanishes at least on the solutions of the syzygies. This corroborates a recent
definition of confining theories. We illustrate our general result by
considering two examples based on the SU(Nc) and Spin(7) gauge theories. We
also examine the role of syzygies in the context of non-Abelian duality. We
emphasize the relevance of non-perturbative effects in the dual magnetic
theories in proving the equivalence of the electric and magnetic syzygies.


title: Hybrid Meson Decay Phenomenology

abstract:
  The phenomenology of a newly developed model of hybrid meson decay is
developed. The decay mechanism is based on the heavy quark expansion of QCD and
the strong coupling flux tube picture of nonperturbative glue. A comprehensive
list of partial decay widths of a wide variety of light, $s\bar s$, $c\bar c$,
and $b \bar b$ hybrid mesons is presented. Results which appear approximately
universal are highlighted along with those which distinguish different hybrid
decay models. Finally, we examine several interesting hybrid candidates in
detail.


title: Hybrid Charmonium Production in NRQCD

abstract:
  Using the operator product expansion and nonrelativistic QCD we study the
production of charmonium hybrids in B decays. We express the decay rate in
terms of a few matrix elements which eventually will be fixed by experimental
measurements or calculated on the lattice. While the Fock state expansion is
problematic for hybrids, the operator product expansion still provides a model
independent framework for phenomenological calculations of hybrid production
and decay. We then use a simple flux tube model to estimate the branching ratio
B -> psi_g+X, where psi_g is a J^{PC}=0^{+-} hybrid, the large production of
which could help resolve the low charm multiplicity observed in B decays.


title: The QCD Tricritical Point: Beyond Monotony in Heavy Ion Physics

abstract:
  I first sketch recent developments concerning the phase diagram of strongly
interacting matter as a function of temperature and baryon density, obtained
using a model for two-flavor QCD in which the interaction between quarks is
modelled on that induced by instantons. The phase diagram has a chiral symmetry
breaking vacuum, a color superconductor phase at high density, and a mixed
phase in between which can describe nuclear matter if the high density regions
in the mixed phase form droplets. This is amusingly similar to the phase
diagram of the copper oxide superconductors, although their critical
temperatures are smaller by a factor of about 10^{-9} and their mixed phase
seems to form stripes, rather than droplets. This and other approaches to QCD
with two massless quarks suggests the existence of a tricritical point on the
boundary of the phase with spontaneously broken chiral symmetry. In QCD with
massive quarks there is then a critical point at the end of a first order
transition line. We discuss possible experimental signatures of this point,
which provide information about its location and properties. We propose a
combination of event-by-event observables, including suppressed fluctuations in
T and mu and, simultaneously, enhanced fluctuations in the multiplicity of soft
pions. As a control parameter (like the collision energy) is varied, the
fluctuations of appropriate event-by-event observables should therefore have
minima or maxima. Experimental detection of these non-monotonic signatures
would confirm that the matter was initially above the chiral phase transition,
increasing our confidence in the interpretation of monotonic changes in other
observables, and would teach us much about the QCD phase diagram.


title: Viscosity of the Scalar Fields from the Classical Theory

abstract:
  We show how the resummation for time dependent quantities at high temperature
can be performed with an effective classical theory. As an application we
demonstrate that the leading term in the shear viscosity, which is related to
the $\rho_{\Phi^2\Phi^2}$ spectral function can be calculated classically,
either using classical linear response theory or from the classical $\Phi^2$
correlation function. The classical result depends explicitly on the cutoff,
and the choice $\Lambda\sim T$ reproduces the known quantum result.


title: New physics potential of double beta decay and dark matter search

abstract:
  The search for neutrinoless double beta decay and WIMP dark matter has a
broad potential to test particle physics beyond the standard model. During the
last years, the analysis of various contributions to the double beta decay rate
by the Heidelberg group led, besides the most restrictive limit on the
effective Majorana neutrino mass, to bounds on left-right-symmetric models,
leptoquarks and supersymmetry. In a general framework bounds on arbitrary
lepton number violating theories can be derived. Using double beta technology
for direct dark matter detection, stringent limits on the spin-independent
WIMP--nucleon interaction have been obtained. These results deduced from the
Heidelberg-Moscow double beta decay experiment are reviewed. Also an outlook on
the future of double beta decay and dark matter search, the GENIUS proposal, is
given.


title: NRQED Approach to the Hyperfine Structure of the Muonium Ground State

abstract:
  The method of NRQED is an adaptation of QED to bound systems. While it is
fully equivalent to QED, it enables us to explore the QED bound states
systematically as an expansion in the fine structure constant $\alpha$ and
velocity ($\sim Z\alpha$) of the bound electron. I describe how to construct
the NRQED Hamiltonian choosing recent works on the $\alpha (Z\alpha)$,
$\alpha^2 (Z\alpha)$,$\alpha (Z\alpha)^2$, $\alpha (Z\alpha)^3$, and $\alpha^2
(Z\alpha)^2$ radiative corrections to the hyperfine structure of the muonium
ground state as examples.


title: Coherence Time in High Energy Proton-Nucleus Collisions

abstract:
  Precisely measured Drell-Yan cross sections for 800 GeV protons incident on a
variety of nuclear targets exhibit a deviation from linear scaling in the
atomic number A. We show that this deviation can be accounted for by energy
degradation of the proton as it passes through the nucleus if account is taken
of the time delay of particle production due to quantum coherence. We infer an
average proper coherence time of 0.4 +- 0.1 fm/c, corresponding to a coherence
path length of 8 +- 2 fm in the rest frame of the nucleus.


title: Four-Neutrino Oscillations

abstract:
  Models with three active neutrinos and one sterile neutrino can naturally
account for maximal oscillations of atmospheric neutrinos, explain the solar
neutrino deficit, and accommodate the results of the LSND experiment. The
models predict either $\nu_e\to\nu_\tau$ or $\nu_e\to\nu_s$ oscillations in
long-baseline experiments with the atmospheric $\delta m^2$ scale and amplitude
determined by the LSND oscillations.


title: Higgs Physics and Supersymmetry

abstract:
  The quest for the physics underlying the breaking of the electroweak symmetry
and the generation of mass is surveyed.


title:
Large Mixing and Large Hierarchy Between Neutrinos with Abelian Flavor
  Symmetries

abstract:
  The experimental data on atmospheric and solar neutrinos suggest that there
is near-maximal mixing between \nu_\mu and \nu_\tau but that their masses are
hierarchically separated. In models of Abelian horizontal symmetries, mixing of
O(1) generically implies that the corresponding masses are of the same order of
magnitude. We describe two new mechanisms by which a large hierarchy between
strongly mixed neutrinos can be achieved in this framework. First, a discrete
Abelian symmetry can give the desired result in three ways: mass enhancement,
mixing enhancement and mass suppression. Second, holomorphic zeros can give
mass suppression.


title: Decays of l=1 Baryons to Delta gamma

abstract:
  Recently we considered the electromagnetic decays of the orbitally-excited
SU(6) 70-plet baryons in large-N_c QCD, fitting to the helicity amplitudes
measured in photoproduction experiments. Using the results of this analysis, we
predict the helicity amplitudes for the decays N^* \to \Delta\gamma and
\Delta^* \to \Delta\gamma. These decays can be studied at a number of new
experimental facilities, and thus provide another nontrivial test of the lowest
order large-N_c predictions.


title: Non SUSY and SUSY one--step Unification

abstract:
  We explore the possibility of achieving one--step unification of the standard
model coupling constants within non supersymmetric and supersymmetric gauge
models, which at low energies have only the standard particle content. The
constraints are the experimental values of $\alpha_{em}$, $\alpha_s$ and
$\sin^2\theta_W$ at $10^2 GeV$, and the lower bounds for FCNC and proton decay
rates. The analysis is done in a model independent way.


title: More on Large $Q^2$ Events with Polarized Beams

abstract:
  We discuss polarized proton-positron scattering in the context of the excess
of large $Q^2$ events at HERA. We define and estimate a polarized asymmetry to
examine two scenarios, the contact interaction and the stop scenario with
broken R-parity. This asymmetry exhibits a characteristic behavior depending on
the scenarios. Thus the polarized experiment at HERA will provide with a good
test for these models.


title: Non-Equilibrium HTL Resummation

abstract:
  We present an extension of the HTL resummation technique to non-equilibrium
situations, starting from the real time formalism in the Keldysh
representation. As an example we calculate the HTL photon self energy, from
which we derive the resummed photon propagator. This propagator is applied to
the computation of the interaction rate of a hard electron in a non-equilibrium
QED plasma. In particular we show the absence of of pinch singularities in
these quantities. Finally we show that the Ward identities relating the HTL
electron self energy to the HTL electron-photon vertex hold as in equilibrium.


title: QCD analysis of inclusive B decay into charmonium

abstract:
  We compute the decay rates and $H$-energy distributions of $B$ mesons into
the final state $H+X$, where $H$ can be any one of the $S$-wave or $P$-wave
charmonia, at next-to-leading order in the strong coupling. We find that a
significant fraction of the observed $J/\psi$, $\psi'$ and $\chi_c$ must be
produced through $c\bar{c}$ pairs in a colour octet state and should therefore
be accompanied by more than one light hadron. At the same time we obtain
stringent constraints on some of the long-distance parameters for colour octet
production.


title:
Searching for Bottom Squarks at Luminosity Upgrades of the Fermilab
  Tevatron

abstract:
  Because of their Yukawa interactions, third generation squarks may be
substantially lighter than those of the first two generations. Assuming that
$\tb_1 \to b\tz_1$ and $\tz_1$ escapes experimental detection, we show that
experiments at the Main Injector upgrade (integrated luminosity of $2 fb^{-1}$)
of the Tevatron should be sensitive to $b$-squark masses up to 210 GeV for
$m_{\tz_1} \leq 120$ GeV. For integrated luminosities of $10 fb^{-1}$ (25
$fb^{-1}$) the sbottom mass reach increases by 20 GeV (35 GeV). If the channel
$\tb_1 \to b\tz_2$ is also accessible, the reach becomes model-dependent and
may be degraded relative to the case where only the decay to $\tz_1$ is
allowed. In models with gaugino mass unification and $\mu$ much larger than
gaugino masses, we argue that this degradation is unlikely to be larger than
30-40 GeV.


title: Introduction to Equilibrium Thermal Field Theory

abstract:
  Within the next few years experiments at RHIC and the LHC will seek to create
in the laboratory a quark-gluon plasma, the phase of matter through which the
Universe passed very early in its life. It is believed that the plasma will
survive long enough to reach thermal equilibrium. I give an introduction to the
formalism of thermal field theory, the combination of statistical mechanics and
quantum field theory needed to describe the plasma in thermal equilibrium, in a
way that tries to keep close to the physics it describes.


title: Mass effects in the quark-gluon decays of heavy paraquarkonia

abstract:
  Quark-gluon decays of heavy paraquarkonia $^1 S_0(\bar Q Q) \to \bar q q g$
are investigated with account of the masses of final quarks. The decay widths
and the energy distributions of the final quarks and gluons are calculated in
dependence on the relative quark masses. The strong collinear enhancement of
the gluon energy distribution at the end of the spectrum is shown to take place
in all such decays of $\eta_c$ and $\eta_b$ mesons except the decay $\eta_b \to
\bar c c g$. The total decay width is shown to have an essential dependence on
the final quark masses. The corresponding branching ratios of $\eta_c$ and
$\eta_b$ mesons are numerically estimated with a good agreement of $Br(\eta_c
\to \bar s s g)$ with experimental data on $\eta_c$ decays.


title: Multijet rates in e+e- annihilation: perturbation theory versus LEP data

abstract:
  We show that the next-to-leading order perturbative prediction, matched with
the next-to-leading logarithmic approximation for predicting both two-, three-
and four-jet rates using the Durham jet-clustering algorithm, in the 0.001 <
ycut < 0.1 range gives a very accurate description of the data obtained at the
Large Electron Positron collider. This information can be utilized either for
simultaneous measurement of the strong coupling and the QCD colour charges, or
for improving the QCD background prediction in new particle searches at LEP2.


title:
Evaluation of hadronic vacuum polarization contribution to muonium
  hyperfine splitting

abstract:
  The contribution of hadronic vacuum polarization (HVP) to the hyperfine
splitting of the muonium ground state is evaluated with the account of modern
experimental data on the cross section of $e^+e^- \to$ annihilation into
hadrons.


title: Parity odd bubbles in hot QCD

abstract:
  We consider the topological susceptibility for an SU(N) gauge theory in the
limit of a large number of colors, $N \to \infty$. At nonzero temperature, the
behavior of the topological susceptibility depends upon the order of the
deconfining phase transition. The most interesting possibility is if the
deconfining transition, at $T=T_d$, is of second order. Then we argue that
Witten's relation implies that the topological susceptibility vanishes in a
calculable fashion at $T_d$. As noted by Witten, this implies that for
sufficiently light quark masses, metastable states which act like regions of
nonzero $\theta$ --- parity odd bubbles --- can arise at temperatures just
below $T_d$. Experimentally, parity odd bubbles have dramatic signatures: the
$\eta'$ meson, and especially the $\eta$ meson, become light, and are copiously
produced. Further, in parity odd bubbles, processes which are normally
forbidden, such as $\eta \to \pi^0 \pi^0$, are allowed. The most direct way to
detect parity violation is by measuring a parity odd global asymmetry for
charged pions, which we define.


title: Inferred 4.4 eV Upper Limits on the Muon- and Tau-Neutrino Masses

abstract:
  By combining experimental constraints from atmospheric and solar neutrino
oscillations and the tritium beta decay endpoint, we infer upper limits of 4.4
eV on the $\nu_\mu$ and $\nu_\tau$ masses, if the universe consists of three
neutrinos. For hierarchical mass spectra $m_3 \gg m_1, m_2$ or $m_3 \simeq m_2
\gg m_1$ we infer that $m_{\nu_\alpha} \lsim 0.08$ eV for $\alpha = e, \mu,
\tau$. In a four neutrino universe, and assuming neutrino oscillations also
account for the LSND experimental results, $m_{\nu_\alpha} \lsim 5.4$ eV. We
also obtain lower limits on the masses.


title:
Sin(phi) azimuthal asymmetry in semi-inclusive electroproduction on
  longitudinally polarized nucleon

abstract:
  We investigate the $sin \phi$ azimuthal asymmetry in the semi-inclusive
deep-inelastic lepton scattering off longitudinally polarized nucleon target
arising from the time reversal odd structures. The order 1/Q contributions of
the leading twist and twist-three distribution and fragmentation functions to
that asymmetry for the certain kinematical conditions are numerically
estimated.


title: Radiative decays of D mesons

abstract:
  The short-distance contribution due to the $c\to u\gamma$ penguin as well as
long-distance contributions are considered in an analysis of $D\to V\gamma$
decays, the latter being dominant. The matrix elements for nine $D\to V\gamma$
transitions are calculated using a hybrid model which combines heavy quark
effective theory and the chiral Lagrangian. We present the expected range of
the branching ratios for these decays, the most frequent ones $D^0\to
\bar{K}^{*0}\gamma$ and $D^+_s \to \rho^+\gamma$, being a few times $10^{-4}$.


title:
Limits on the magnetic moment of sterile neutrino and two-photon
  neutrino decay

abstract:
  It is shown that the non-zero transition magnetic moment ($\mu_{tran}$)
between the sterile neutrino ($\nu_{s}$) and the muon neutrino ($\nu_{\mu}$)
could be effectively searched for via the Primakoff effect, in the process of
$\nu_{\mu} Z \to \nu_{s}Z$ conversion in the external Coulomb field of a
nucleus $Z$, with the subsequent $\nu_{s}\to \nu_{\mu} + \gamma$ decay. From
the recent results of the NOMAD neutrino detector at CERN a model-independent
constraint of $\mu_{tran} < (10^{-6} - 10^{-9}) \mu_{B}$ is obtained depending
on the value of $\nu_{s}$ mass. For the $m_{s}\sim O(1) GeV$ region these
bounds are comparable with the present experimental ones on $\nu_{\mu}$ and
$\nu_{e}$ diagonal magnetic moments and are more sensitive than those on
$\nu_{\tau}$ magnetic moment.
  From the same analysis the constraint on $\nu_{\tau}(\nu_{s})\to \nu_{\mu}
+\gamma + \gamma$ decay lifetime $\tau > 2\times10^{13} sec/m_{\nu}^{7}(MeV)$
is obtained. The limit is valid for neutrino masses up to $m_{\nu}\sim
O(1)GeV$.


title:
Scheme dependence, leading order and higher twist studies of MRST
  partons

abstract:
  We extend a recent global analysis of nucleon parton distributions carried
out at next-to-leading order (NLO) in the MSbar scheme to provide distributions
in the so-called DIS scheme. We pay particular attention to the translation of
the heavy quark distributions in going from the MSbar to the DIS scheme. We
repeat the global analysis at leading order (LO) and comment on the major
effects produced when going from LO to NLO. Finally we include in the global
analysis a freely parameterised form of possible higher twist contributions to
make an exploratory study of the size of these effects as a function of x.


title:
Radiative Corrections to Deep Inelastic Scattering in the Presence of an
  Additional Z' at LEP x LHC

abstract:
  The study of ep-scattering at LEP x LHC offers an interesting opportunity to
search for additional heavy neutral gauge bosons. We study the influence of
radiative corrections, especially of the potentially large QED contributions,
to the expected cross sections. These corrections are typically of the same
order as the effect searched for or even larger and have to be taken into
account properly.


title: Correlations and fluctuations '98

abstract:
  Summary talk at the VIIIth International Workshop on Multiparticle Production
"Correlations and Fluctuations '98" held at Matrahaza, Hungary, from 14th till
21st of June 1998.


title: ZZ' Mixing in Presence of Standard Weak Loop Corrections

abstract:
  We derive a method for a common treatment of Z' exchange, QED corrections,
and weak loops. It is based on the form factor approach to the description of
weak loop corrections to partial Z widths and cross sections. Problems
connected with ZZ' mixing are discussed with special care. Our theoretical
results are applied to the package ZFITTER. We demonstrate two different ways
to the data analysis - one based on an extension of the standard model cross
sections, the other on model-independent formulae together with the Z width
calculations in presence of a Z'. With the resulting package ZEFIT+ZFITTER,
LEP1 data from fermion pair production, including Bhabha scattering, can be
analysed on, but also off the Z peak. Further, the code may be used at very
high energies, e.g. in the region of a possible future linear e+e- collider.


title: Heavy Quark Fragmentation in Deep Inelastic Scattering

abstract:
  We perform an analysis of semi-inclusive production of charm (D-mesons) in
neutral current (NC) and charged current (CC) deep inelastic scattering (DIS)
at full O(alpha_s^1). Our calculation is based on the heavy quark scheme
developed by Aivazis, Collins, Olness and Tung (ACOT) where we include an
O(alpha_s^1) calculation of quark scattering contributions for general masses
and couplings. We review the relevant massive formulae and subtraction terms
and discuss their massless limits. We show how the charm fragmentation function
can be measured in CC DIS and we investigate whether the charm production
dynamics may be tested in NC DIS. We also discuss finite initial state quark
mass effects in CC and NC DIS.


title: SU(N) Elastic Rescattering in B and D Decays

abstract:
  The treatment of elastic final state interactions (FSI) under a symmetry
group is presented. The proposed model is based on Watson's theorem, i.e. on
symmetry properties of the S-matrix and on its unitarity. This theorem provides
an easy way to introduce rescattering effects by defining final state
interactions mixing matrices. A symmetry group fixes the structure of such
mixing matrices, and the passage from one group to another is studied (for
example, SU(2) to SU(3)). Mixings among two charmless pseudoscalar decay
product states will be systematically analyzed. Finally, these mixing matrices
will be used on quark diagram parametrizations of B and D decay amplitudes.
This will have some important consequences on the definition of quark diagrams.
It will be argued that these diagrams should not contain any FSI effects, i.e.
they should be real (except for CKM factors). FSI are then introduced at the
hadronic level, by mixing basic quark diagram topologies.


title: Signals for CP-Violation in Scalar Tau Pair Production at Muon Colliders

abstract:
  We discuss signals for CP-violation in $\mu^+ \mu^- \to \tilde \tau_i^-
\tilde \tau_j^+$, where $i,j = 1,2$ label the two scalar $\tau$ mass
eigenstates. We assume that these reactions can proceed through the production
and decay of the heavy neutral Higgs bosons present in supersymmetric models.
CP-violation in the Higgs sector can be probed through a rate asymmetry even
with unpolarized beams, while the CP-odd phase associated with the $\tilde
\tau$ mass matrix can be probed only if the polarization of at least one beam
can be varied. These asymmetries might be ${\cal O}(1)$.


title: Bremsstrahlung of a Quark Propagating through a Nucleus

abstract:
  The density of gluons produced in the central rapidity region of a heavy ion
collision is poorly known. We investigate the influence of the effects of
quantum coherence on the transverse momentum distribution of photons and gluons
radiated by a quark propagating through nuclear matter. We describe the case
that the radiation time substantially exceeds the nuclear radius (the relevant
case for RHIC and LHC energies), which is different from what is known as
Landau-Pomeranchuk-Migdal effect corresponding to an infinite medium. We find
suppression of the radiation spectrum at small transverse photon/gluon momentum
k_T, but enhancement for k_T>1GeV. Any nuclear effects vanish for k_T > 10GeV.
Our results allow also to calculate the k_T dependent nuclear effects in prompt
photon, light and heavy (Drell-Yan) dilepton and hadron production.


title: Rare B Decays in Supersymmetry without R-parity

abstract:
  We perform the complete computation of the contributions to $b\to s+\gamma,
b\to s e^{+}e^{-}, b\to s\sum \nu_{i} \bar{\nu}_{i}$ in supersymmetric model
with bilinear R-parity violation. We compare our calculations with the
evaluations in SM and the experimental results. We find that the supersymmetric
contributions can be quite large in those processes.
  From the analysis and experimental results, we can get some constraints on
the mass spectrum in the model.


title: Large N_f calculations in deep inelastic scattering

abstract:
  We describe the evaluation of the anomalous dimensions of twist-2 deep
inelastic light cone operators to O(1/N_f) as a check on future perturbative
calculations. In particular we present recent results for the singlet gluonic
operator dimension in polarised and unpolarised scattering and give three loop
predictions for the O(1/N_f) gluonic eigenoperator. The section of the 3-loop
O(1/N_f) DGLAP splitting function proportional to the adjoint quadratic Casimir
is also calculated for the singlet gluonic operators.


title: The Strange Magnetic Moment of the Proton in the Chiral Quark Model

abstract:
  The strange magnetic moment of the proton is small in the chiral quark model,
because of a near cancellation between the quantum fluctuations that involve
kaons and $s$-quarks and loops that involve radiative transitions between
strange vector mesons and kaons.


title: Derivative expansions of Euclidean thermal effective actions

abstract:
  I compute the derivative expansion of an effective action at finite
temperature using the imaginary time approach. I show that it is a well behaved
expansion giving a unique seriers contrary to previous results. This disparity
is shown to originate in the choice of thermal Green functions used in the
calculations.


title: The Unique Derivative Expansion for Thermal Effective Actions

abstract:
  I show that there is a unique and well behaved derivative expansion of an
effective action at finite temperature. The result is true for all formalisms
including the popular Closed Time Path and Imaginary Time methods.


title: Rapidity gaps and color evolution in QCD hard scattering

abstract:
  We discuss rapidity-gap events between two jets produced at high momentum
transfer in $p$ $\bar{p}$ scattering, from the point of view of the soft energy
flow into the interjet region. We define a gap cross section and, in
perturbative QCD (pQCD), resum all the leading logarithms in the soft
intermediate energy. We show that the numerical result from our cross section
reproduces the shape of the D0 and CDF \cite{D0,CDF,D0fig} experimental data.


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

abstract:
  We compute the QCD corrections to the decay rate difference in the $B_s-\bar
B_s$ system, $\Delta\Gamma_{B_s}$, in the next-to-leading logarithmic
approximation using the heavy quark expansion approach. Going beyond leading
order in QCD is essential to obtain a proper matching of the Wilson
coefficients to the matrix elements of local operators from lattice gauge
theory. The lifetime difference is reduced considerably at next-to-leading
order. We find $(\Delta\Gamma/\Gamma)_{B_s}=(f_{B_s}/210 MeV)^2 [0.006
B(m_b)+0.150 B_S(m_b)-0.063]$ in terms of the bag parameters $B, B_S$ in the
NDR scheme. As a further application of our analysis we also derive the
next-to-leading order result for the mixing-induced CP asymmetry in inclusive
$b\to u\bar ud$ decays, which measures $\sin 2\alpha$.


title: Phenomenology of Neutral D-meson Decays and Double-Flavor Oscillations

abstract:
  Decays of neutral D-mesons are considered phenomenologically without invoking
any particular models. Special attention is given to cascade decays with
intermediate neutral kaons where coherent double-flavor oscillations (CDFO)
become possible. We show necessity and unique possibilities of experiments on
CDFO. They allow to relate with each other widths and masses of D-meson
eigenstates, to separate interference effects due to $D^0 - \bar D^0$ mixing
and/or Cabibbo-favored vs. doubly-suppressed transitions. Such experiments
provide the only known ways to unambiguous model-independent measurements of
all CP-violating parameters and of Cabibbo-doubly-suppressed amplitudes, where
the New Physics may have more prominent manifestations. Similar experiments
would be useful and interesting also for charged $D$-meson decays to neutral
kaons.


title: Deacay and scattering amplitudes are not the same

abstract:
  We study the lowest lying $\pi^+ \pi^-$ resonance R, bound by the long range
Coulomb potential and destabilized by short range strong interactions mediating
the dominant decay into two neutral pions. Parametrizing the corresponding
partial decay width by $\Gamma (R \to 2 \pi^0) = 2/9 \alpha^3 \sqrt{m_{\pi^+}^2
- m_{\pi^0}^2} (\Delta a_{D} m_{\pi^+})^2$ the quantity $\Delta a_{D}$ depends
within QCD & QED on four basic parameters : $\Lambda_{QCD}, m_{u} + m_{d},
\alpha, m_{d}- m_{u}$. We are interested here only in the limit where the last
two parameters vanish $\Delta a_{D}^{0} = \Delta a_{D} (\Lambda_{QCD}, m_{u} +
m_{d}, \alpha = 0, m_{d} - m_{u} = 0)$.
  While isospin invariance implies $\Delta a_{D}^{0} = a_{D}^{I = 0} - a_{D}^{I
= 2}$ it is shown that beyond the first order expansion in the strong
interaction the identities $a_{D}^{I} = a^{I}$, where $a^{I}$ denote the strong
interaction scattering lengths, do not hold.


title:
Do the SuperKamiokande atmospheric neutrino results explain electric
  charge quantisation?

abstract:
  We show that the SuperKamiokande atmospheric neutrino results explain
electric charge quantisation, provided that the oscillation mode is $\nu_{\mu}
\to \nu_{\tau}$ and that the neutrino mass is of Majorana type.


title: Two-loop renormalization of Wilson loop for Drell-Yan production

abstract:
  We study the renormalization of the Wilson loop with a path corresponding to
the Drell-Yan lepton pair production in two-loop approximation of perturbation
theory. We establish the renormalization group equation in next-to-leading
order and find a process specific anomalous dimension Gamma_DY in the
corresponding approximation.


title: Radiative Neutrino Decay in Media

abstract:
  In this letter we introduce a new method to determine the radiative neutrino
decay rate in the presence of a medium. Our approach is based on the
generalisation of the optical theorem at finite temperature and density.
Differently from previous works on this subject, our method allows to account
for dispersive and dissipative electromagnetic properties of the medium. Some
inconsistencies that are present in the literature are pointed-out and
corrected here. We shortly discuss the relevance of our results for neutrino
evolution in the early universe.


title: Decay constant of pion in the quark model

abstract:
  To describe pion as a bound state of two quark, when their current masses are
non equal to zero, is considered. In the framefowrk of the potential
approximate the Schwinger-Dyson and Bethe-Salpeter equations are solved. The
quark-antiquark interaction as sum of the oscillator and Coulomb potential is
chosen. The mass and constant of pion are calculated.


title: The Massive Yang-Mills Model and Diffractive Scattering

abstract:
  We argue that the massive Yang-Mills model of Kunimasa and Goto, Slavnov, and
Cornwall, in which massive gauge vector bosons are introduced in a
gauge-invariant way without resorting to the Higgs mechanism, may be useful for
studying diffractive scattering of strongly interacting particles. We perform
in this model explicit calculations of S-matrix elements between quark states,
at tree level, one loop, and two loops, and discuss issues of renormalisability
and unitarity. In particular, it is shown that the S-matrix element for quark
scattering is renormalisable at one-loop order and is only logarithmically
non-renormalisable at two loops. The discrepancies in the ultraviolet regime
between the one-loop predictions of this model and those of massless QCD are
discussed in detail. Also, some of the similarities and differences between the
massive Yang-Mills model and theories with a Higgs mechanism are analysed at
the level of the S-matrix. Finally, we briefly discuss the high-energy
behaviour of the leading-order amplitude for quark-quark elastic scattering in
the diffractive region. The above analysis sets up the stage for carrying out a
systematic computation of the higher order corrections to the two-gluon
exchange model of the Pomeron using massive gluons inside quantum loops.


title: New developments in the 1/N expansion and nonperturbative Higgs physics

abstract:
  We show in this paper that the 1/N expansion is a reliable tool to calculate
the properties of a heavy Higgs boson. The 1/N expansion sums up all orders in
perturbation theory, and therefore avoids the renormalization scheme dependence
of the conventional perturbative approach. It is explained how effects due to
the Landau pole of the Higgs sector are isolated and subtracted, and how to
perform actual calculations, by computing the Higgs line shape for the
processes f\bar f\to H \to ZZ,f'\bar f' at next-to-leading order in the 1/N
expansion. The results are compared to the perturbative results to show the
agreement between the perturbative and the nonperturbative approach for Higgs
masses up to 1 TeV. We conclude that the theoretical predictions for Higgs
observables are well under control for the entire kinematical region of the
LHC.


title: Hadronization in Heavy-Ion Reactions

abstract:
  We present a model of fast hadronization of constituent quark matter in
relativistic heavy ion collisions based on rate equations and capture cross
sections in non-relativistic potential. We utilize a thermodynamically
consistent approach with a non-ideal equation of state including correlation
terms based on string phenomenology. We investigate strange and non-strange
particle ratios observed in CERN SPS experiments.


title:
Neutrino electron scattering and electroweak gauge structure: Probing
  the masses of a new Z boson

abstract:
  Low-energy high-resolution neutrino-electron scattering experiments may play
an important role in testing the gauge structure of the electroweak
interaction. We discuss the use of strong radioactive neutrino sources (e.g.
$^{51}$Cr) in underground experiments such as BOREXINO, HELLAZ and LAMA. We
display the sensitivity of these detectors in testing the possible existence of
extra neutral $E_6$ gauge bosons.


title:
Two-loop renormalization group restrictions on the standard model and
  the fourth chiral family

abstract:
  In the framework of the two-loop renormalization group, the global profile of
the Standard Model (SM) in its full parameter space is investigated up to the
scale of the gauge singularity. The critical Higgs masses bordering the strong
coupling, unstable and the safe regions are explicitly found. Restrictions on
the Higgs boson mass as a function of a cutoff scale are obtained from the
stability of the electroweak vacuum and from the absence of the strong coupling
both in the Higgs and Yukawa sectors. The cutoff being equal to the Plank scale
requires the Higgs mass to be M=(161.3+-20.6)+4-10 GeV and M>=140.7+-10 GeV,
where the M corridor is the theoretical one and the errors are due to the top
mass uncertainty.
  The SM two-loop beta-functions are generalized to the massive neutrino case.
Modification of the two-loop global profile of the SM extended by one new
chiral family is studied, and bounds on the masses of the family are found. The
requirement of self-consistency of the perturbative SM as an underlying theory
up to the Planck or GUT scale excludes the fourth chiral family with the mass
up to 250 GeV depending on the Higgs mass and the cutoff scale. Under precision
experiment restriction M<=200 GeV, the fourth chiral family, taken alone, is
excluded. Nevertheless a pair of the chiral families constituting the
vector-like one could still exist.


title: Limits on Pauli principle violation by nucleons

abstract:
  We consider nuclei produced in core collapse supernovae and subjected to a
high neutron flux. We show that an accelerator mass spectrometry experiment
that searched for traces of anomalous iron isotopes could set limits on the
order of $10^{-20}-10^{-25}$ on (or perhaps discover) Pauli principle violation
by neutrons. A similar search for anomalous Co isotopes could set limits in the
range $10^{-13}-10^{-18}$ on Pauli principle violation by protons. We show that
existing data on Oxygen can be used to set a limit of about $10^{-17}$ in one
proposed model of such violation.


title:
The Wilson Renormalisation Group Applied to the Potential in NN
  Scattering

abstract:
  Nonrelativistic two-body scattering by a short-ranged potential is studied
using the renormalisation group. Two fixed points are identified: a trivial one
and one describing systems with a bound state at zero energy. The eigenvalues
of the linearised renormalisation group are used to assign a systematic
power-counting to terms in the potential near each of these fixed points. The
expansion around the nontrivial fixed point defines a power counting scheme
which is equivalent to the effective-range expansion.


title:
A Color Mutation Model of Soft Interaction in High Energy Hadronic
  Collisions

abstract:
  A comprehensive model, called ECOMB, is proposed to describe multiparticle
production by soft interaction. It incorporates the eikonal formalism, parton
model, color mutation, branching and recombination. The physics is conceptually
opposite to the dynamics that underlies the fragmentation of a string. The
partons are present initially in a hadronic collision; they form a single,
large, color-neutral cluster until color mutation of the quarks leads to a
fission of the cluster into two color-neutral subclusters. The mutation and
branching processes continue until only $q\bar q$ pairs are left in each small
cluster. The model contains self-similar dynamics and exhibits scaling behavior
in the factorial moments. It can satisfactorily reproduce the intermittency
data that no other model has been able to fit.


title: Constraints on top couplings in models with exotic quarks

abstract:
  The extension of the Standard Model with exotic quark singlets and doublets
introduces large flavor changing neutral couplings between ordinary fermions.
We derive inequalities which translate the precise determination of the
diagonal Z couplings, in particular at LEP, into stringent bounds on the
off-diagonal ones. The resulting limits can be saturated in minimal extensions
with one vector doublet or singlet. In this case, 23 and 6 single top events,
respectively, are predicted at LEP2 for an integrated luminosity of 500 1/pb
per experiment.


title: Nucleosynthesis Bounds in Gauge-Mediated Supersymmetry Breaking Theories

abstract:
  In gauge-mediated supersymmetry breaking theories the next-to-lightest
supersymmetric particle can decay during or after the nucleosynthesis epoch.
The decay products such as photons and hadrons can destroy the light element
abundances. Restricting the damage that these decays can do leads to
constraints on the abundance and lifetime of the NLSP. We compute the freezeout
abundance of the NLSP by including all coannhilation thresholds which are
particularly important in the case in which the NLSP is the lightest stau. We
find that the upper bound on the messenger scale can be as stringent as 10^12
GeV when the NLSP is the lightest neutralino and 10^13 GeV when the NLSP is the
lightest stau. Our findings disfavour models of gauge mediation where the
messenger scale is close to the GUT scale or results from balancing
renormalisable interactions with non-renormalisable operators at the Planck
scale. When combined with the requirement of no gravitino overabundance, our
bound implies that the reheating temperature after inflation must be less than
10^7 GeV.


title: Unresolved Questions in J/psi Production and Propagation in Nuclei

abstract:
  In order to understand the J/psi suppression arising from the possible
occurrence of the quark-gluon plasma in high-energy heavy-ion collisions, it is
necessary to have a comprehensive picture how the J/psi and its precursors are
produced, what their properties after production are, and how the J/psi and its
precursors propagate inside nuclear matter. There are unresolved questions in
the descriptions of J/psi production and propagation. We outline some of these
questions and discuss the approaches for their resolution.


title: Gluon Radiation in Top Quark Production and Decay at an e^+ e^- Collider

abstract:
  We study the effects of gluon radiation on top production and decay processes
at an $e^+e^-$ collider.The matrix elements are computed without any
approximations, using spinor techniques. We use a Monte Carlo event generator
which takes into account the infrared singularity due to soft gluons and
differences in kinematics associated with radiation in the production versus
decay process. The calculation is illustrated for several strategies of top
mass reconstruction.


title: General Relativistic effects in preheating

abstract:
  General relativistic effects in the form of metric perturbations are usually
neglected in the preheating era that follows inflation. We argue that in
realistic multi-field models these effects are in fact crucial, and the fully
coupled system of metric and quantum field fluctuations needs to be considered.
Metric perturbations are resonantly amplified, breaking the scale-invariance of
the primordial spectrum, and in turn stimulate scalar field resonances via
gravitational rescattering. This non-gravitationally dominated nonlinear growth
of gravitational fluctuations may have significant effects on the Doppler peaks
in the cosmic background radiation, primordial black hole formation,
gravitational waves and nonthermal symmetry restoration.


title:
Statistical interpretations of the null result of the KARMEN 2
  experiment

abstract:
  Several possible statistical interpretations of the null result of the KARMEN
2 neutrino oscillation experiment are discussed with the aim of clarifying the
implications of the fact that KARMEN 2 did not observe any of the expected
background events. The formalism that allows to take into account the error of
the expected mean background in a Poisson process with background is presented
and applied to the statistical analysis of the KARMEN 2 null result. The
possibility of ignoring the expected mean background calculated for the KARMEN
2 experiment is discussed and it is shown that the resulting exclusion curves
are ultra-conservative, but may be a safe choice in such a controversial case.
It is also shown that the sensitivity curves of neutrino oscillation
experiments cannot be considered as exclusion curves. The implications of the
different statistical analyses of the KARMEN 2 null result for the
compatibility of the results of the KARMEN 2 and LSND experiments is discussed.


title: CP Violating B Decays with R-parity Violation

abstract:
  We study CP violating B decays in the minimal supersymmetric standard model
with R-parity violation. We estimate how much R-parity violation modifies the
SM predictions for CP asymmetries in B decays within the present bounds. The
effects of R-parity- and lepton-number-violating couplings on the ratio of the
decay amplitude due to R-parity violation to that of the SM can differ by one
or two orders of magnitudes depending on the models of the left-handed quark
mixing. It is possible to disentangle the R-parity violating effects from those
of the SM and R-parity- conserving supersymmetric models within the present
bounds comparing different CP violating decay amplitudes. We also study the
effects of R-parity- and baryon-number-violating couplings and find that the
effects could be large.


title: DIRAC Experiment at CERN: Lifetime Measurement of Pionium

abstract:
  The DIRAC experiment, a magnetic double arm spectrometer, aims to measure the
$\pi^+\pi^-$ atom lifetime with 10% precision, using the high intensity 24
GeV/c proton beam of the CERN Proton Synchrotron. Since the value of this
lifetime of order $10^{-15}$~s is dictated by strong interaction at low energy,
a precise measurement of this quantity enables to study characteristic pion
parameters in detail and to submit predictions of QCD to a severe check.


title: Dipole Form Factors and Loop-induced CP-violation in Supersymmetry

abstract:
  The one-loop Minimal Supersymmetric Standard Model (MSSM) contributions to
the weak and electromagnetic dipole form factors of heavy fermions are
reviewed. For the $Z$ boson on shell, the weak-magnetic and weak-electric
dipole moments of the $\tau$ lepton and the $b$ quark can be defined and
directly connected to observables. But far from the $Z$ peak, the weak and
electromagnetic dipole form factors are not enough to account for all the new
physics effects. In the context of the calculation of the process $e^+e^-\to
t\bar{t}$ to one loop in the MSSM, we compare the impact on the phenomenology
of the CP-violating dipole form factors of the top quark with the contribution
from CP-violating box graphs. Some exemplificative observables are analyzed and
the relevance of both the contributions is pointed out. The set of tensor
integrals employed, the one-loop expressions for the electromagnetic and weak
dipole form factors in a general renormalizable theory and the SM and MSSM
couplings and conventions are also given.


title: Vacuum Structure of the $\mu$-Problem Solvable Extra U(1) Models

abstract:
  Vacuum structure and related phenomenological features are investigated in
$\mu$-problem solvable supersymmetric extra U(1) models. We present a framework
for the analysis of their vacuum structure taking account of an abelian gauge
kinetic term mixing, which can potentially modify a scalar potential and $Z^0$
gauge interactions. Applying this to data of the precise measurements at LEP,
we constrain an allowed region in a space of Higgs vacuum expectation values
based on consistency with potential minimum conditions. We find that such a
region is confined into rather restricted one. Bounds on masses of an extra
U(1) gauge boson and the lightest neutral Higgs boson are predicted.
Renormalization group equations for gauge coupling constants and gaugino soft
masses in an abelian gauge sector are also discussed in relation to the gauge
kinetic term mixing in some detail.


title:
Lepton-Flavor Violation in the Left-handed Slepton Production at Future
  Lepton Colliders

abstract:
  The Super-Kamiokande atmospheric neutrino data suggest existence of the large
lepton-flavor violating (LFV) interaction in the higher energy scale. If the
minimal supersymmetric standard model is extended to have right-handed
neutrinos, the left-handed sleptons in the second and third generations are
expected to have the LFV masses in the minimal supergravity scenario. In this
article we study the LFV signals in the left-handed slepton production at
$\mu^+\mu^-$ colliders and $\e^+\e^-$ linear colliders (LC's),
$\mu^+\mu^-(\e^+\e^-)\to\tau\mu +4jets + \E$ and
$\mu^+\mu^-(\e^+\e^-)\to\tau\mu l+ 2jets+ \E$. The main background comes from
decay of a tau lepton into a muon in the lepton-flavor conserving slepton pair
production. They are significantly reduced by the energy and the impact
parameter cuts for the muon. At $\mu^+\mu^-$ colliders (LC's) it may be
possible to reach the mixing angle $\sin 2\theta_{\tilde{\nu}} \gsim 0.1(0.5)$
and the mass difference $\Delta m_{\tilde{\nu}}\gsim 0.1(0.4)$ GeV for the
sneutrinos in the second and third generations at the statistical significance
of $3\sigma$. Such small mass difference and a mixing angle may be induced
radiatively even if the Yukawa coupling constant for the tau neutrino is of the
order of 0.1.


title: Experimental Constraints on the Cabibbo-Kobayashi-Maskawa Matrix

abstract:
  The LEP investigation of the Bd and Bs oscillations and of the
Cabibbo-Kobayashi-Maskawa matrix element Vub improve the constraints on the
other elements of this matrix.
  From a fit to the experimental data and the theory calculations it is
possible to determine the vertex of the unitarity triangle as:
  rho = 0.155 -0.105 +0.115 eta = 0.383 -0.060 +0.063.
  The corresponding values of its angles, in their customary definition in
terms of sines for alpha and beta, are:
  sin(2 alpha) = 0.08 -0.50 +0.43 sin(2 beta) = 0.75 +/- 0.10 gamma = 68 +/-
15o.
  The fit also yields indirect information on the compatibility with zero of
the CP violating phase of the matrix, on some non-perturbative QCD parameters
and on the Bs oscillation frequency.


title:
Charged Higgs Mass Bounds from b -> s gamma in a Bilinear R-Parity
  Violating Model

abstract:
  The experimental measurement of $B(b \to s\gamma)$ imposes important
constraints on the charged Higgs boson mass in the MSSM. If squarks are in the
few TeV range, the charged Higgs boson mass in the MSSM must satisfy
$m_{H^{\pm}} \gsim 440$ GeV. For lighter squarks, then light charged Higgs
bosons can be reconciled with $B(b \to s\gamma)$ only if there is also a light
chargino. In the MSSM if we impose $m_{\chi^{\pm}_1}>90$ GeV then we need
$m_{H^{\pm}} \gsim 110$ GeV. We show that by adding bilinear R--Parity
violation (BRpV) in the tau sector, these bounds are relaxed. The bound on
$m_{H^{\pm}}$ in the MSSM--BRpV model is $\gsim 340$ GeV for the the heavy
squark case and $m_{H^{\pm}} \gsim 75$ GeV for the case of light squarks. In
this case the charged Higgs bosons would be observable at LEP II. The
relaxation of the bounds is due mainly to the fact that charged Higgs bosons
mix with staus and they contribute importantly to $B(b \to s\gamma)$.


title:
Scalar and Vector Leptoquark Pair Production at Hadron Colliders: Signal
  and Backgrounds

abstract:
  We perform a systematic analysis of scalar and vector leptoquark pair
production at the Fermilab Tevatron and at the CERN LHC. We evaluate signal
expectations and background levels for the processes pp (p ppar) -> 2 jets +
e^{+} + e^{-} and 2 jets + e + missing p_T. The Monte Carlo event generator
ISAJET is used to simulate the experimental conditions at the current
(Sqrt{s}=1.8 TeV, Luminosity=100 pb^{-1}) and upgraded (Luminosity=100 pb^{-1})
Tevatron as well as the LHC (Sqrt{s}=14 TeV, Luminosity=10 fb^{-1}). Depending
on the luminosity, and assuming a branching ratio B(LQ -> eq)=0.5, we find a
discovery reach up to 170 (255) GeV for scalar leptoquarks at the current
(upgraded) Tevatron. Similarly, we find vector leptoquarks to be detectable at
masses below 300 (400) GeV depending on the coupling. At the LHC, the discovery
reach is enhanced to 1 TeV for scalar leptoquarks and to 1.5 TeV for vectors.


title:
Two-loop renormalization group profile of the standard model and a new
  generation

abstract:
  The two-loop renormalization group global profile of the Standard Model (SM)
in its full parameter space is investigated. Restrictions on the Higgs boson
mass as a function of a cutoff scale are obtained from the stability of the
electroweak vacuum and from the perturbative validity both in the Higgs and
Yukawa sectors. The cutoff equal to the Planck scale requires the Higgs mass to
be M=(161.3+-20.6)+4-10 GeV and M>=140.7+-10 GeV, where the M corridor is the
theoretical one and the errors are due to the top mass uncertainty.
Modification of the two-loop global profile of the SM extended by one new
chiral generation is studied, and bounds on the masses of the generation are
derived. Under the precision experiment restriction M<=200 GeV, the forth
chiral generation, taken alone, is excluded. Nevertheless a pair of the chiral
generations constituing the vector-like one could exist.


title: Putative Light Scalar Nonet

abstract:
  We investigate the "family" relationship of a possible scalar nonet composed
of the a_0(980), the f_0(980) and the \sigma and \kappa type states found in
recent treatments of \pi\pi and \pi K scattering. We work in the effective
Lagrangian framework, starting from terms which yield "ideal mixing" according
to Okubo's original formulation. It is noted that there is another solution
corresponding to dual ideal mixing which agrees with Jaffe's picture of scalars
as qq\bar q \bar q states rather than as q\bar q states. At the Lagrangian
level there is no difference in the formulation of the two cases (other than
the numerical values of the coefficients). In order to agree with experiment,
additional mass and coupling terms which break ideal mixing are included. The
resulting model turns out to be closer to dual ideal mixing than to
conventional ideal mixing; the scalar mixing angle is roughly -17 degrees in a
convention where dual ideal mixing is 0 degrees.


title:
Partial Summary of Section a (CONFINEMENT Mechanism, Flux Tubes and
  String)

abstract:
  An overview of some issues discussed is given, including the following ones:
(i) the mechanism of confinement, (ii) the structure of the string, (iii)
non-perturbative glue in vacuum and hadrons, and (v) quark-hadron duality. In
doing so I try to indicate issues important for JLab. Finally I discuss another
issue debated during this conference, namely (vi) whether one can use some
common effective potential for description of various hadrons, using heavy
quarkonia as an example.


title: QCD Phase Shifts and Rising Total Cross-Sections

abstract:
  Energy dependence of $\gamma^*p$ total cross section is considered. It is
known from the HERA data that the cross section grows with energy, and the rate
of growth is an increasing function of the virtuality $Q^2$ of the photon
$\gamma^*$. This dependence can be explained in a simple and generic way by the
Froissart bound. To implement this mechanism quantitatively a theory satisfying
$s$-channel unitarity is required. This is achieved by computing the total
cross section from the optical theorem, and the forward elastic amplitude from
the phase shifts in the impact-parameter representation. A recipe to do so in
perturbative QCD is discussed, together with an expose of the advantage to
calculate the elastic amplitude via phase shift, rather than direct sum of all
Feynman diagrams. A two-loop computation of phase shift and total cross section
is presented, and compared with the HERA data with good agreements.


title: Physics at the Interface of Particle Physics and Cosmology

abstract:
  In these lectures I examine some of the principal issues in cosmology from a
particle physics point of view. I begin with nucleosynthesis and show how the
primordial abundance of the light elements can help fix the number of (light)
neutrino species and determine the ratio $\eta$ of baryons to photon in the
universe now. The value of $\eta$ obtained highlights two of the big open
problems of cosmology: the presence of dark matter and the need for
baryogenesis. After discussing the distinction between hot and cold dark
matter, I examine the constraints on, and prospect for, neutrinos as hot dark
matter candidates. I show next that supersymmetry provides a variety of
possibilities for dark matter, with neutralinos being excellent candidates for
cold dark matter and gravitinos, in some scenarios, possibly providing some
form of warm dark matter. After discussing axions as another cold dark matter
candidate, I provide some perspectives on the nature of dark matter before
turning to baryogenesis. Here I begin by outlining the Sakharov conditions for
baryogenesis before examining the issues and challenges of producing a, large
enough, baryon asymmetry at the GUT scale. I end my lectures by discussing the
Kuzmin-Rubakov-Shaposhnikov mechanism and issues associated with electrical
baryogenesis. In particular, I emphasize the implications that generating the
baryon asymmetry at the electroweak scale has for present-day particle physics.


title: Neutrino Oscillations and Lepton Flavor Mixing

abstract:
  In view of the recent announcement on non-zero neutrino mass from
Super-Kamiokande experiment, it would be very timely to investigate all the
possible scenarios on masses and mixings of light neutrinos. Recently suggested
mass matrix texture for the quark CKM mixing, which can be originated from the
family permutation symmetry and its suitable breakings, is assumed for the
neutrino mass matrix and determined by the four combinations of solar,
atmospheric and LSND neutrino data and cosmological hot dark matter bound as
input constraints. The charged-lepton mass matrix is assumed to be diagonal so
that the neutrino mixing matrix can be identified directly as the lepton flavor
mixing matrix and no CP invariance violation originates from the leptonic
sector. The results favor hierarchical patterns for the neutrino masses, which
follow from the case when either solar-atmospheric data or solar-HDM
constraints are used.


title: On the treatment of confinement in three-quark calculations

abstract:
  The treatment of confining interactions in non-relativistic three-quark
systems is revised. Usually in the Faddeev equations the Faddeev components are
coupled by the total potential. In the new treatment the Faddeev components are
coupled only by the non-confining short-range part of the potential, allowing
thus its channel-by-channel investigation. The convergence in angular momentum
channels is much faster.


title: Double Chiral Logs

abstract:
  We determine the full structure of the leading (double-pole) divergences of
O(p^6) in the meson sector of chiral perturbation theory. The field theoretic
basis for this calculation is described. We then use an extension of this
result to determine the p^6 contributions containing double chiral logarithms
(L^2), single logarithms times p^4 constants (L x L_i^r) and products of two
p^4 constants (L_i^r x L_j^r) for F_\pi, F_K/F_\pi, K_{l3} and K_{e4} form
factors. Numerical results are presented for these quantities.


title: Searching for QCD-Instantons at HERA

abstract:
  We review the present status of our ongoing systematic study of the discovery
potential of QCD-instanton induced events in deep-inelastic scattering at HERA.


title: On the Observability of "Invisible" / "Nearly Invisible" Charginos

abstract:
  It is shown that if the charginos decay into very soft leptons or hadrons +
$\not{E}$ due to degeneracy/ near- degeneracy with the LSP or the sneutrino,
the observability of the recently proposed signal via the single photon (+ soft
particles) + $\not{E}$ channel crucially depends on the magnitude of the $\SNU$
mass due to destructive interferences in the matrix element squared. If the
$\SNU$'s and, consequently, left-sleptons are relatively light, the size of the
signal, previously computed in the limit $\MSNU \to \infty$ only, is
drastically reduced. We present the formula for the signal cross section in a
model independent way and discuss the observability of the signal at LEP 192
and NLC energies.


title: Resummation of soft modes in the free energy of Phi^4 theory

abstract:
  A new method is proposed for the calculation of the free energy of an
N-component Phi^4 theory at finite temperature. The method combines a
perturbative treatment of the hard modes with a non-perturbative treatment in
the effectively three-dimensional sector of the soft modes. The separation
between hard and soft modes is achieved by the effective field theory method of
Braaten and Nieto. One- and two-loop gap equations for the screening mass are
used to resum higher order effects in the soft sector. The proposed method is
similar to the screened perturbation theory of Karsch, Patkos, and Petreczky
albeit avoiding the difficulty of solving gap equations in the full
four-dimensional theory. Since gap equations are only used in the
three-dimensional effective theory the tedious evaluation of Matsubara sums is
not necessary. This simplification makes it possible to go beyond the one-loop
gap equation. The large N as well as the finite N case are discussed.


title:
Basis independent parametrisations of R parity violation in the soft
  SUSY breaking sector

abstract:
  The magnitude of R-parity violating coupling constants depends on which
direction in the space of weak doublets with hypercharge = -2 corresponds to
the Higgs. To address this ``basis dependence'', one can construct combinations
of coupling constants that are invariant under these basis transformations, and
which parametrise how much R parity violation is present in the Lagrangian
(analogous to Jarlskog invariants for CP violation). This has previously been
done for the Higgs vev and the R parity violating couplings constants in the
superpotential. In this letter, I build invariants that include soft SUSY
breaking interactions, and briefly discuss their relation to invariants
involving the Higgs vev. This completes the construction of invariants based on
the MSSM with baryon parity.


title:
Single spin asymmetries in transversely polarized proton(antiproton) -
  proton inclusive processes

abstract:
  We consider several single spin asymmetries in inclusive, transversely
polarized proton(antiproton) - proton processes as higher twist QCD
contributions, taking into account spin and intrinsic transverse momentum
effects in the quark distribution functions. This approach has been previously
applied to the description of the single spin asymmetries observed in
transversely polarized proton - proton -> pion + X reactions and all its
parameters fixed: we give here predictions for new processes, which agree with
experiments for which data are available, and suggest further possible
measurements.


title: Cosmological Constraints on B-L Violation

abstract:
  This is a review of the cosmological bounds on $B-L$ violating interactions,
and the loopholes in the argument that gives these constraints. If one assumes
that the baryon asymmetry we observe today was present above the electroweak
phase transition in equilibrium with the non-perturbative $B+L$ violating
processes, then interactions that violate all three of ${B/3 - L_i}$ cannot
simultaneously be in equilibrium. Otherwise the baryon asymmetry would be
washed out. Therefore violation of at least one of the $B/3 - L_i$ must be
small. This argument can be evaded by not having the observed baryon asymmetry
present in the thermal bath (for instance, make it at the electroweak phase
transition), by using a non-standard cosmological model, or possibly by some
mass effects in models where the difference between lepton flavour asymmetries
is conserved.


title:
CP violation flavor asymmetries in slepton pair production at leptonic
  colliders from broken R parity

abstract:
  We examine the effect of the R parity odd renormalizable interactions on
flavor non-diagonal rates and CP violation asymmetries in the production of
slepton pairs at $e^- - e^+$ leptonic colliders, for center of mass energies
spanning the interval from the Z-boson pole up to 1000 GeV. The lepton number
violating interactions, associated with the lepton number violating coupling
constants, are assumed to incorporate CP odd complex phases. The flavor
changing rates are controlled by tree level amplitudes and quadratic products
of different R parity violating coupling constants and the CP asymmetries by
interference terms between tree and loop level amplitudes and quartic products.
The consideration of loop amplitudes is restricted to the photon and Z-boson
vertex corrections. We present numerical results using a family and species
independent mass parameter, $\tilde m$, for all the scalar superpartners and
making simple assumptions for the family dependence of the R parity odd
coupling constants. The flavor non-diagonal rates, $\s_{JJ'}$, vary in the
range, $(\l/0.1)^4 2 - 20$ fbarns, as one spans the interval of center of mass
energies from the Z-boson pole up to 1000 GeV. For sleptons masses, $\tilde m>
150 $ GeV, these observables could be of use at NLC energies to set useful
bounds on the R parity odd coupling constants. The values of the asymmetries,
vary from a few to a few tens of $10^{-3}$.


title: Spin correlations in $e^+e^-\to 4 jets$

abstract:
  Existence of discrepancies between experimental data and Monte Carlo
predictions for angular distributions in four-jet production via $e^+e^-$
annihilation has been known for some time at LEP1. As such QCD processes
constitute significant backgrounds to $e^+e^-\to W^+W^-\to 4$-jet production at
LEP2, we consider the possibility that an erroneous modelling of the helicity
structure of the final-state partons could affect the accuracy of experimental
measurements of the $W^\pm$ boson parameters


title: Six-jet production at lepton colliders

abstract:
  We study electron-positron annihilations into six jets at the parton level in
perturbative Quantum Chromo-Dynamics (QCD), via the elementary processes
$e^+e^-\ar q\bar q gggg$, $e^+e^-\ar q\bar q q'\bar q' gg$ and $e^+e^-\ar q\bar
q q'\bar q' q''\bar q''$, for massive quarks $q, q'$ and $q''$ and massless
gluons $g$. Several numerical results of phenomenological relevance are given,
at three different collider energies and for a representative selection of jet
clustering algorithms. We also present helicity amplitudes and colour factors
needed for the tree-level calculation


title: CP Violating B ---> s Gamma Decay in Supersymmetric Models

abstract:
  Supersymmetric models with nonuniversal down type squark masses can enrich
the chiral structure and CP violating phenomena in $b\to s\gamma$ decays.
Direct CP violation in $b\to s \gamma$, mixing induced CP violation in
radiative $B_{d,s}$ decays (such as $B_s\to \phi \gamma$ and $B_d \to
K^*_{1,2}\gamma$), and $\Lambda$ polarization in $\Lambda_b \to \Lambda \gamma$
can be substantially different from the Standard Model. Future experiements at
$e^+ e^-$ and hadronic B factories will give important information on the
underlying theory for radiative $b$ decays.


title: The Forward Cone and L/T Separation in Diffractive DIS

abstract:
  LPS provides access to new fundamental observables: the diffraction cone and
azimuthal asymmetries. Diffraction cone has a unique rise of $B_T$ from the
exclusive limit to excitation of continuum $M^2 \approx Q^2$ which is in
striking contrast to experience with real photoproduction and hadronic
diffraction. Azimuthal asymmetry is large and pQCD calculable at large $\beta$
and can be measured with LPS. It allows testing of the pQCD prediction of $L/T
>> 1$.


title: Higgs Radiation off Top Quarks in e^+e^- Collisions

abstract:
  The strength of the Yukawa coupling of the leptons and quarks with the Higgs
boson is uniquely determined by the Higgs mechanism for generating masses in
the Standard Model. The top-Higgs coupling can be measured directly in the
process e^+e^- --> t tbar H. This process therefore provides a fundamental test
of the Higgs mechanism. Extending earlier analyses carried out in the Born
approximation, we have determined the cross section for this process including
QCD corrections, which turn out to be important.


title: Quark model and strange baryon production in heavy ion collisions

abstract:
  It is pointed out that the recent data on strange baryon and antibaryon
production in Pb-Pb collisions at 159 GeV/c agree well with the hypothesis of
an intermediate state of quasi-free and randomly distributed constituent quarks
and antiquarks. Also the S-S data are consistent with this hypothesis. The p-Pb
data follow a different pattern.


title: Thermal Supersymmetry in Thermal Superspace

abstract:
  Thermal superspace is characterized by Grassmann variables which are
time-dependent and antiperiodic in imaginary time, with a period given by the
inverse temperature. The thermal superspace approach allows to define thermal
superfields obeying consistent boundary conditions and to formulate a
``super-KMS'' condition for superfield propagators. Upon constructing thermal
covariantizations of the superspace derivative operators, we define thermal
covariant derivatives and provide a definition of thermal chiral and antichiral
superfields. Thermal covariantizations of the generators of the
super-Poincar\'e algebra are also constructed, and the thermal supersymmetry
algebra is computed; it has the same structure as at T=0. We then investigate
realizations of this thermal supersymmetry algebra on systems of thermal
fields. In doing so, we observe thermal supersymmetry breaking in terms of the
lifting of the mass degeneracy, and of the non-invariance of the thermal
action.


title: The Feynman-Wilson gas and the Lund model

abstract:
  We derive a partition function for the Lund fragmentation model and compare
it with that of a classical gas. For a fixed rapidity ``volume'' this partition
function corresponds to a multiplicity distribution which is very close to a
binomial distribution. We compare our results with the multiplicity
distributions obtained from the JETSET Monte Carlo for several scenarios.
Firstly, for the fragmentation vertices of the Lund string. Secondly, for the
final state particles both with and without decays.


title:
Forward diffraction dissociation of the virtual photons at small x_Bj in
  the QCD dipole picture

abstract:
  Forward differential cross-section for diffraction dissociation of virtual
photons on nucleon target is calculated in the QCD dipole picture.
  The numerical estimates are presented and discussed.


title: The Confining Interaction and Radiative Decays of Heavy Quarkonia

abstract:
  The radiative spin-flip transition rates of heavy quarkonium states depend
sensitively on the matrix elements of the effective confining interaction
through the associated two-quark exchange current operator. The Hamiltonian
model based on a scalar linear confining interaction with a single gluon
exchange hyperfine term is shown to provide an adequate description of the
$J/\psi\to \eta_c\gamma$ and $\psi(2S)\to \eta_c\gamma$ decay widths once the
relativistic single quark magnetic moment operator is treated without
approximation and the exchange current is taken into account. Predictions are
given for the radiative spin-flip decay widths of the 1S,2S and 3S states of
the $c\bar c$, $b\bar b$ and $B_c^+$ systems. In the B_c^+ system the gluon
exchange current also contributes to the spin-flip transition rates.


title: The Electroweak Phase Transition in the MSSM

abstract:
  The construction of an effective 3D theory at high temperatures for the MSSM
as a model of electroweak baryogenesis is discussed. The analysis for a single
light scalar field shows, that given the experimental constraints, there is no
value of the Higgs mass for which a sufficiently first-order phase transition
is obtained. A precise determination of the 3D parameters of the effective
theory for the case of a light right-handed stop allows us to obtain an upper
bound on the masses of the lightest Higgs and right-handed stop using the
two-loop effective potential. A two-stage phase transition persists for a small
range of values of $m_{\tilde{t}_{R}}$.


title:
Exclusive production of vector mesons $\rho, \rho'$ and $\rho''$ by real
  and virtual photons

abstract:
  We present a non-perturbative QCD calculation of high-energy diffractive
photo- and leptoproduction of vector mesons $\rho$, $\rho'$ and $\rho''$ on a
nucleon. The initial photon splits up in a $q\bar{q}$-dipole and transforms
into a vector meson by scattering on the quark-diquark nucleon. The
dipole-dipole scattering amplitude is provided by the non-perturbative model of
the stochastic QCD vacuum, the wave functions result from considerations on the
light-cone. We assume the physical $\rho'$- and $\rho''$-states to be mixed
states of an active 2S-excitation and a rest whose coupling to the photon is
suppressed. We obtain good agreement with the experimental data and get an
understanding of the markedly different spectrum in the $\pi^+\pi^-$-invariant
mass for photoproduction and $e^+e^-$-annihilation.


title:
Effective chiral theory of mesons, coefficients of ChPT, axial-vector
  symmetry breaking

abstract:
  A review of effective chiral theory of pseudoscalar, vector, and axial vector
mesons is presented. 10 coefficients of the ChPT are predicted. A new symmetry
breaking-axial-vector symmetry breaking is found and applied to EW theory. The
masses of W and Z are dynamically generated and in agreement with data.


title: One-Particle Inclusive Semi-Leptonic B decays

abstract:
  We propose a method for a QCD based calculation of one-particle inclusive
decays of the form B \to \bar D X or B \to \bar D^* X. It is based on the heavy
mass limit and a short distance expansion of the amplitudes, which yield a
power series in the parameter 1/M^2_X for the spectra and in \Lambda_QCD
m_b/(m_b - m_c)^2 for the rates. We study the leading term of this expansion
for the case of the semi--leptonic decays B \to \bar D X l^+ \nu.


title: QCD Corrections to Associated Higgs Boson-Heavy Quark Production

abstract:
  We compute the O(alpha_s) QCD corrections to the inclusive process e^+e^- -->
t \bar t h. Although the total rate is small, it has a distinctive experimental
signature and can potentially be used to measure the top quark-Higgs boson
Yukawa coupling. The QCD corrections increase the rate by a factor of roughly
1.5 for e^+e^- --> t \bar t h at sqrt(s)=500 GeV and Mh=100 GeV. At sqrt(s)=1
TeV, the corrections are small.


title:
An Effective Field Theory Approach to Color Superconductivity at High
  Quark Density

abstract:
  We investigate the Fermi Liquid theory of high density QCD. Using the
renormalization group (RG), we determine the behavior of effective fermion
interactions near the Fermi surface. At sufficiently high densities the
matching between the Fermi Liquid theory and QCD can be accomplished in
perturbation theory and a reliable calculation of Cooper pair formation
performed, modulo the existence of a magnetic screening mass for the gluon. The
presence of a chemical potential leads to different RG flows for sub-components
of the effective interactions which would ordinarily be linked by Lorentz
invariance. We also study instanton-induced operators and find that near the
Fermi surface they are likely to be subdominant relative to operators induced
by perturbative gluon exchange. We discuss the implications of our results for
the phase structure of QCD at finite baryon density and temperature.


title: Properties of the B_{C} System

abstract:
  I summarize a comprehensive account of the energies, splittings and
electromagnetic decays of the low-lying states of the bottom charmed meson
system. Richardson's potential is used to include running coupling constant
effects in the central potential, and the full radiative one-loop expressions
derived by Pantaleone, Tye and Ng are used for the spin-dependent potentials.
Our result for the ground state energy is 6286 +15 -6 MeV. The ground state
lifetime is found to be 0.36 + 0.05 - 0.05 ps. Both of these numbers are
consistent with the measured values recently announced by the CDF collaboration
at Fermilab.


title: Evading the GZK Cosmic-Ray Cutoff

abstract:
  Explanations of the origin of ultra-high energy cosmic rays are severely
constrained by the Greisen-Zatsepin-Kuz'min effect, which limits their
propagation over cosmological distances. We argue that possible departures from
strict Lorentz invariance, too small to have been detected otherwise, can
affect elementary-particle kinematics so as to suppress or forbid inelastic
collisions of cosmic-ray nucleons with background photons. Thereby can the GZK
cutoff be relaxed or removed.


title: A Reexamination of Proton Decay in Supersymmetric Grand Unified Theories

abstract:
  We reconsider dimension-five proton decay operators, making semi-quantitative
remarks which apply to a large class of supersymmetric GUTs in which the
short-distance operators are correlated with the fermion Yukawa couplings. In
these GUTs, which include minimal SU(5), the operators
$(u^cd_i^c)^\dagger(d_j\nu_\tau)$, induced by charged Higgsino dressing,
completely dominate for moderate to large $\tanbeta$. The rate for $p \rarr
(K^+,\pi^+) \bar{\nu}_\tau$ grows rapidly, as $\tanbeta^4$, and the K^+ to
\pi^+ branching ratio can often be precisely predicted. At small $\tanbeta$ the
operators $(u d_i)(d_j \nu)$ are dominant, while the operators $(u d_i)(u
\ell^-)$, with left-handed charged leptons, are comparable to the neutrino
operators in the generic GUT and suppressed in minimal GUTs. Charged-lepton
branching fractions are always small at large $\tanbeta$. The electron to muon
ratio is small in minimal GUTs but can be larger, even of order one, in other
models. All other operators are very small. At small $\tanbeta$ in non-minimal
GUTs, gluino and neutralino dressing effects on neutrino rates are not
negligible.


title: Search for SUSY and Higgs particles

abstract:
  An overview of hints for new physics outside the Standard Model and the
status of sparticle and Higgs searches is given. The present limits on Higgs
bosons of about 90 GeV as well as the $\bsg$ rate and cosmological constraints
severely restrict the available parameter space of the MSSM.