title: New Types of Accessible Environmental Influence on Neutrino Oscillation

abstract:
  To describe possible effects of medium, besides the hamiltonian introduced by
Mikheev, Smirnov and Wolfenstein (MSW), in principle, there may exist new terms
in the evolution equation for the neutrino oscillation due to the environment.
Considering a two-energy-level quantum system: $\nu_1-\nu_2$, two-species
neutrino system which is embedded in a matter environment, we solve the
neutrino evolution equation precisely with the possible extra terms,
especially, those cause alternations between pure and mixed states of the
neutrino quantum system. We obtain some remarkable features for the neutrino
oscillations, which are different from that of MSW and accessible to be
observed in solar neutrino observation and/or in the planned long-baseline
neutrino experiments.


title: Neutrino mixing from neutrino oscillation data

abstract:
  We show that the existing neutrino oscillation data are in favour of the
schemes with mixing of four massive neutrinos and that only two of these
schemes, with two pairs of neutrinos with close masses separated by a gap of
about 1 eV, are compatible with all data. Possible implications of these
schemes for future experiments are discussed.


title: Strange Antibaryons from QGP

abstract:
  We study as function of the collision energy and stopping the thermal
conditions reached in a quark-gluon plasma fireball formed in a relativistic
heavy ion collision. We explore strange particle yields for the current round
of Pb-Pb and Au-Au experiments.


title:
Cosmic Strings, Zero Modes and SUSY breaking in Nonabelian N=1 Gauge
  Theories

abstract:
  We investigate the microphysics of cosmic strings in Nonabelian gauge
theories with N=1 supersymmetry. We give the vortex solutions in a specific
example and demonstrate that fermionic superconductivity arises because of the
couplings and interactions dictated by supersymmetry. We then use supersymmetry
transformations to obtain the relevant fermionic zero modes and investigate the
role of soft supersymmetry breaking on the existence and properties of the
superconducting strings.


title: Electroweak Theory and the 1996/97 Precision Electroweak Data

abstract:
  We review the empirical evidence for the validity of the Standard Electroweak
Theory in Nature. The experimental data are interpreted in terms of an
effective Lagrangian for Z physics, allowing for potential sources of SU(2)
violation and containing the predictions of the Standard Electroweak Theory as
a special case. Particular emphasis is put on discriminating loop corrections
due to fermion-loop vector-boson propagator corrections on the one hand, from
corrections depending on the non-Abelian structure and the Higgs sector on the
other hand. Results from recently obtained fits of the Higgs-boson mass are
reported, yielding M_H < 430 GeV [680 GeV] at 95% C.L. based on the input of
\swbar^2(\LEP+\SLD)_{`97} = 0.23152 +- 0.00023 [\swbar^2(\LEP)_{`97} = 0.23196
+- 0.00028]. The LEP2 data provide first direct experimental evidence for
non-zero non-Abelian couplings among the electroweak vector bosons.


title:
Pion Exchange Currents in Neutrinoless Double Beta Decay and Limits on
  Supersymmetry

abstract:
  We examine the pion exchange mode of neutrinoless double beta decay induced
by the R-parity violating quark-lepton operators of the supersymmetric (SUSY)
extensions of the standard model of the electroweak interactions. The
corresponding nuclear matrix elements are evaluated within the renormalized
quasiparticle random phase approximation with proton-neutron pairing, which
includes the Pauli effect of fermion pairs and does not collapse for a physical
value of the nuclear force strength. It is argued that the pion-exchange mode
of neutrinoless double beta decay dominates over the conventional two-nucleon
mode in the case of the SUSY mechanism. As a result sensitivity of neutrinoless
double beta decay to the SUSY contribution turns out to be significantly better
that previously expected from the two-nucleon mode calculations. An upper limit
on the R-parity violating coupling $\lambda'_{111}$ is derived from
non-observation of neutrinoless double beta decay. This limit is much stronger
than that expected from the near future accelerator experiments.


title: Low-energy Anti-neutrinos from the Sun

abstract:
  We consider the sensitivity of future neutrino experiments in the low energy
region, such as BOREXINO or HELLAZ, to a solar electron antineutrino signal. We
show that, if neutrino conversions within the Sun result in partial
polarization of initial solar neutrino fluxes, then a new opportunity arises to
observe the electron antineutrinos and thus to probe the Majorana nature of the
neutrinos. This is achieved by comparing the slopes of the energy dependence of
the differential neutrino electron scattering cross section for different
neutrino conversion scenarios. We also show how the \nu_e -> \bar{\nu}_e
conversions may take place for low energy solar neutrinos while being
unobservable at the Kamiokande and Super-Kamiokande experiments.


title: New dynamical symmetry breaking in eletroweak theory

abstract:
  A new dynamical symmetry breaking of $SU(2)_{L}\times U(1)$ caused by the
combination of the axial-vector component and the fermion mass is found in
electroweak theory. We obtain (m^{2}_{W}={1/2}g^{2}m^{2}_{t}) and
(m^{2}_{Z}=\rho m^{2}_{W}/cos^{2}\theta_{W}) with (\rho\simeq 1), (G_{F}={1/2
\sqrt{2}m^{2}_{t}})}}). Two fixed gauge fixing terms for W and Z boson fields
are dynamically generated. Massive neutrinos are required.


title: NLO correction to Higgs boson parameters in the 1/N expansion

abstract:
  We present the result of a calculation of the next-to-leading correction to
the Higgs propagator in the 1/N expansion, where the Higgs sector is treated as
an O(N) symmetric sigma-model. The results are compared with two-loop
perturbation theory. The existing discrepancy between the lowest order of the
1/N expansion and perturbation theory is dramatically reduced by including the
NLO in 1/N. We find a maximum effective Higgs mass of 930-980 GeV. We give an
approximate relation between Higgs width and mass, which can be used for
phenomenological purposes.


title:
The two-pion spectra for the reaction \pi^- p -> \pi^0\pi^0 n at 38
  GeV/c pion momentum and combined analysis of the GAMS, Crystal Barrel and BNL
  data

abstract:
  We perform the K-matrix analysis of meson partial waves with IJ^{PC}
=00^{++}, 10^{++}, 02^{++}, 12^{++} basing on GAMS data on \pi^-p -> \pi^0\pi^0
n, \eta\eta n, \eta\eta' n together with BNL data on \pi^-p -> K\bar K n and
Crystal Barrel data on p\bar p (at rest) -> \pi^0\pi^0\pi^0, \pi^0\eta\eta,
\pi^0\pi^0\eta. The positions of the amplitude poles (physical resonances) are
determined as well as the positions of the K-matrix poles (bare states) and the
values of bare state couplings to two-meson channels. Nonet classification of
the determined bare states is discussed.


title: Does the ``Soft Pomeron'' Cope with the HERA Data?

abstract:
  It is demonstrated that the "soft pomeron" (together with a secondary
reggeon) describing cross-sections of hadron-hadron collisions is fairly able
to describe the energy dependence of cross-sections of exclusive (virtual)
photoproduction of vector mesons $(\rho^0, \phi, J/\psi)$ obtained at HERA.
However these poles are insufficient for description of the total DIS
cross-section.


title: Strangeness and Particle Freeze-out in Nuclear Collisions at 14.6 Gev a

abstract:
  We study the chemical conditions at freeze-out associated with the production
of strange-particles in Si-Au collisions at 14.6 GeV A. We obtain freeze-out
chemical potentials and temperature, and determine the entropy as well as the
final particle abundance. We also consider in detail the alternative evolution
scenarios involving the hadronic gas and the deconfined phase.


title: Weak Electric Dipole Moments of Heavy Fermions in the MSSM

abstract:
  A minimal supersymmetric version of the Standard Model with complex
parameters allows contributions to the weak-electric dipole moments of fermions
at the one-loop level. Assuming generation-diagonal trilinear
soft-susy-breaking terms and the usual GUT constraint, a set of CP-violating
physical phases can be introduced. In this paper the general expressions for
the one-loop contribution to the WEDM in a generic renormalizable theory are
given and the size of the WEDM of the tau lepton and the b quark in such a
supersymmetric model is discussed.


title: The Double Scattering Contribution to $b_1(x,Q^2)$ in the Deuteron

abstract:
  We study the tensor structure function $b_1\xq$ in deep inelastic scattering
(DIS) of an electron from a polarized deuteron target. We model the
electron-nucleon cross section at the starting point for $Q^2$ evolution by
vector-meson-dominance (VMD). Shadowing due to the double-scattering of vector
mesons, along with the presence of a d-state admixture in ground state deuteron
wave function gives rise to a non-vanishing contribution to $b_1\xq$. Although
significant at large Bjorken $x$, the restoration of rotational symmetry for
small $x$ ($\leq10^{-3}$) requires that $b_1^{(2)}\xq$ approach zero as $x\to
0$ in this model. If the model is valid, it should apply within the range of
present fixed target experiments.


title: Formation and Evolution of the Quark-Gluon Plasma

abstract:
  Imposing an equilibrium between the thermal pressure of deconfined quarks and
gluons and the dynamical compression pressure exercised by in-flowing nuclear
matter, we study the initial thermal conditions reached in a quark-gluon plasma
fireball formed in a relativistic heavy ion collision. We show that entropy is
produced primarily in the pre-equilibrium stage of the reaction. We test our
approach, comparing our results with the S-W/Pb collision results at 200 GeV A
and find a surprising degree of agreement assuming about 50% stopping. We apply
our method to a determination of the conditions in collisions of Au-Au at 11
GeV A and Pb-Pb at 157 GeV A, assuming full stopping of momentum, energy and
baryon number. Our detailed results directly determine the spectral shape and
abundance of (strange) hadrons and electromagnetic probes (photons, dileptons)
produced in the collision, and we explore specific experimental consequences.


title: CP Violating Anomalous Couplings at a 500 GeV e+ e- Linear Collider

abstract:
  We study the sensitivity of a 500 GeV $e^+e^-$ Linear Collider to $CP$
violating anomalous couplings. We find that with 50~fb$^{-1}$, and taking only
one non-zero coupling at a time, the process $e^+e^-\to W^+ W^-$ can be used to
place the 95% confidence level bounds $|\tilde\kappa_\gamma|\leq0.1$,
$|\tilde\kappa_Z|\leq 0.1$ and $|g_4^Z|\leq 0.1$ from CP even observables. By
studying certain distributions in the process $e^+e^-\to
\mu^+\mu^-\nu\bar{\nu}$ one of the bounds can be improved to $|g_4^Z| \leq
0.06$. This process also allows the construction of a CP odd observable which
can be used to place bounds on CP violating new physics. At the 95% confidence
level we find $|\tilde\kappa_\gamma|\leq 0.3$, $|\tilde\kappa_Z|\leq 0.2$ and a
much weaker bound for $|g_4^Z|$.


title: New Sum Rules for Nucleon Tensor Charges

abstract:
  Two new sum rules for the quark tensor charges of the nucleon are proposed,
based on a relation connecting the quark transversity distributions to the
quark helicity distributions and the quark model spin distributions, and on the
sum rules for the quark helicity distributions. The two sum rules are useful
for an estimate of the values of the quark tensor charges $\delta U$ and
$\delta D$ from the measured quantities of $\Gamma^p$, $\Gamma^n$, $g_A/g_V$
and $\Delta S$, and two model correction factors with limited uncertainties. We
predict a small value for the sum of the quark tensor charges compared to most
other predictions, in analogy to the unexpectedly small quark helicity sum
which gave rise to the proton ``spin puzzle''.


title:
Massive Quark Production in Electron Positron Annihilation to Order
  $\alpha_s^2$

abstract:
  Recent analytical and numerical results for the three-loop polarization
function allow to present a phenomenological analysis of the cross section for
massive quark production in electron positron annihilation to order
$\alpha_s^2$. Numerical predictions based on fixed order perturbation theory
are presented for charm and bottom production above 5 and 11.5 GeV,
respectively. The contribution from these energy regions to $\alpha(M_Z^2)$,
the running QED coupling constant at scale M_Z, are given. The dominant terms
close to threshold, i.e. in an expansion for small quark velocity $\beta$, are
presented.


title: Detecting the Higgs Bosons of Minimal Supergravity with Muon Pairs

abstract:
  The prospects at the CERN LHC are investigated for the discovery via decays
into muon pairs of neutral Higgs bosons in the minimal supergravity model.
Promising results are found for the CP-odd pseudoscalar ($A^0$) and the heavier
CP-even scalar ($H^0$) Higgs bosons at large $\tan\beta \equiv v_2/v_1$. For
$\tan\beta \agt 10$ and 100 GeV $\alt m_A,m_H \alt$ 550 GeV, the $A^0$ and the
$H^0$ masses could be precisely reconstructed from the dimuon invariant mass.


title:
Multiplicity difference correlators under first-order QGP phase
  transition

abstract:
  The multiplicity difference correlators between two well-separated bins in
high-energy heavy-ion collisions are studied as a means to detect evidence of a
first-order quark-hadron phase transition. Analytical expressions for the
scaled factorial moments of multiplicity difference distribution are obtained
for small bin size $\delta$ with mean multiplicity in the bin ${\bar s}\le 1.0$
within Ginzburg-Landau description. The scaling behaviors between the moments
are still valid, though they behave completely different from the so-called
intermittency patterns. A universal exponent $\gamma=1.4066$ is given to
describe the dynamical fluctuations in the phase transition in small $\delta$
limit.


title: New Viewpoint to the Source of Weak CP Phase

abstract:
  The relation between CP-violation phase angle and the other three mixing
angles in Cabibbo-Kobayashi-Maskawa matrix is postulated. This relation has a
very definite geometry meaning. The numerical result coincides surprisingly
with that extracting from the experiments. It can be further put to the more
precise tests in the future.


title: Stabilization of the Electroweak String by the Bosonic Zero Mode

abstract:
  In the minimal standard model we discuss stability of the Z-string
configuration, which includes the zero mode connected with the broken gauge
symmetry. The zero mode induces charge and current on the string and gives
backreaction to the string profile changing the region of dynamical stability.
For \sin ^2\theta_W=0.23 it is found that the string is stabilized for the
Higgs mass M_H<132 GeV in some finite range of the time-like currents.


title: Periodicity and quark-antiquark static potential

abstract:
  Beyond the standard model, a static potential between quark pairs is obtained
phenomenologically (QCD inspired), associated with the range of strong
interaction, when the virtual exchange gluon squared momentum transfer has a
periodicity for periodic boundary conditions of the quark-pair system enclosed
by a constant volume, in the lowest order of the effective perturbed QCD (in
which the gluon propagator is replaced by the effective gluon one). This
potential includes a periodicity dependent effect, characterized by a finite
face value of the periodicity $N$, in addition to the periodicity independent
potential (the Coulomb type plus linear one). That periodicity dependent
effect, dominant at short distance, is applied to an explanation of the top
quark mass $$m_t=8\pi m_\pi N^{{1/2}},$$ whose numerically calculated results
indicate approximately both upper and lower bounds of $m_t$
  $$177~\mbox{{GeV}} > m_t > 173 ~\mbox{{GeV}}$$ for the range of strong
interaction $L=1.40~fm~(=m_\pi^{-1})$.


title: QED Corrections to Deep Inelastic Scattering with Tagged Photons at HERA

abstract:
  We calculate the QED corrections to deep inelastic scattering with tagged
photons at HERA in the leading logarithmic approximation. Due to the special
experimental setup, two large scales appear in the calculation that lead to two
large logarithms of comparable size. The relation of our formalism to the
conventional structure function formalism is outlined. We present some
numerical results and compare with previous calculations.


title: Cosmic Ray particle production

abstract:
  The status of some popular models to simulate hadronic and nuclear
interactions at Cosmic Ray energies is reviewed. The models predict the rise of
all the hadronic and nuclear cross sections with energy and a smooth
(logarithmic) rise of average multiplicities, rapidity plateaus and average
transverse momenta with the energy. The importance is stressed to put more
effort into the models and especially a better understanding of the minijet
component at the highest energies. Likewise, experimental data on particle
production are needed at the highest possible energies, to guide the models.


title:
O(\alpha_s^2) contributions to the fragmentation function g_1(x,Q^2) in
  polarized e^+e^- annihilation

abstract:
  Misprints in the C_F^2 part of the splitting function \Delta P_{gq}^(1) Eq.
(3.29) are corrected. Due to a minus sign error between the C_F^2- 1/2 C_A C_F
piece and the remaining part of Eq. (A.4), Eq. (3.46) is changed. Finally
z_{qq}^{PS,(2)} is know so that we can give the full expression for \Delta \bar
{\cal C}_{1,q}^{PS} in Eq. (A.1).


title: Four-fermion production at LEP2 and NLC

abstract:
  The present knowledge on four-fermion production in electron-positron
collisions is reviewed, with emphasis on W boson physics. Different methods to
extract M_W from the data are presented and the role of QCD loop corrections
discussed.


title: Two lectures on heavy quark production in hadronic collisions

abstract:
  These lectures present a pedagogical introduction to the physics of
heavy-flavour production in hadronic collisions. The first lecture gives the
theoretical background, with a discussion of leading-order calculations and of
the effects of next-to-leading-order corrections. The origin and implications
of the large logarithmic corrections appearing at this order are presented in
an elementary way. The second lecture provides a survey of current experimental
data on charm and bottom production, and describes their comparison with
theoretical predictions. We emphasize the role played by some non-perturbative
effects in the determination of charm distributions, and study the theoretical
systematic uncertainties which affect our predictions.


title:
Decay constants, semi-leptonic and non-leptonic decays in a
  Bethe-Salpeter Model

abstract:
  We evaluate the decay constants for the B and $D$ mesons and the form factors
for the semileptonic decays of the B meson to $D$ and $D^*$ mesons in a
Bethe-Salpeter model. From data we extract $V_{cb}=0.039 \pm 0.002$ from ${\bar
B} \to D^* l {\bar{\nu}} $ and $V_{cb}=0.037 \pm 0.004$ from ${\bar B} \to D l
{\bar{\nu}} $ decays. The form factors are then used to obtain non-leptonic
decay partial widths for $ B\to D \pi (K) $ and $B \to D D (D_s) $ in the
factorization approximation.


title: On the anomalous U(1) in free fermionic superstring models

abstract:
  The realistic free fermionic models have had an intriguing success in
explaining different properties of the observed particle spectrum. In this
paper we discuss in some detail the anomalous U(1) symmetry which exists in
these models. We study the properties of the anomalous U(1) in both the more
realistic NAHE--based free fermionic models and those in a general NAHE class.
Appearance of an anomalous U(1) in the more realistic NAHE models is shown to
be an effect of reduction of world-sheet supersymmetry from (2,2) to (2,0). We
show, however, that in more general (2,1) and (2,0) models, all U(1) can remain
anomaly-free under certain conditions. Several phenomenological issues related
to the anomalous U(1) are discussed. In particular, we note that in some
examples the anomalous U(1) arises from the breaking $E_6 -> SO(10) X U(1)_A$,
resulting in $U(1)_A$ being family universal.


title:
Phenomenological neutrino mass matrix for neutrino oscillations and dark
  matter

abstract:
  A phenomenological neutrino mass matrix is proposed to explain the solar and
atmospheric neutrino deficits and to present the neutrino as a candidate of hot
dark matter in the $3\nu_L+3\nu_R$ framework. The realization of mixing angles
which can explain the solar and atmospheric neutrino problems is taken as the
first criterion in this construction. The differences among neutrino mass
eigenvalues are introduced as a perturbation. In this scheme the structure of a
charged lepton mass matrix is not severely constrained by the solar and
atmospheric neutrino data.


title:
Hara's theorem, quark model, and gamma_5-dependent renormalization
  constants

abstract:
  We discuss the applicability of gamma_5-dependent field renormalization as a
means of renormalizing away the apparent violation of Hara's theorem observed
in the quark model. It is pointed out that a result totally analogous to the
violation of Hara's theorem is predicted by the quark model also for neutral
baryons. For neutral baryons, however, such a result cannot be renormalized
away. This proves that gamma_5-dependent renormalization does not provide a
proper way for a hadron-level understanding of the violation of Hara's theorem
observed in the quark model.


title: A Composite Model of Quarks with the `Effective Supersymmetry'

abstract:
  We present a composite model of quarks with `effective supersymmetry'. The
model is based on the gauge group $(SU(2)_S \times SU(2)_M) \times (SU(2)_U
\times SU(2)_C \times SU(2)_T) \times SU(5)_{SM}$, where $SU(5)_{SM}$ is the
standard model gauge group. In the dynamical supersymmetry breaking sector
based on the gauge group $SU(2)_S \times SU(2)_M$, supersymmetry is dynamically
broken. The preon sector is constructed by the model proposed by Nelson and
Strassler. The fermion mass hierarchy among the up-type quarks originates from
the $SU(2)_U \times SU(2)_C \times SU(2)_T$ gauge dynamics. The supersymmetry
breaking is mediated to the minimal supersymmetric standard model sector by the
`preon' superfields which compose the quarks in the first two generations. To
obtain an experimentally acceptable mass spectrum, the scalar quarks in the
first two generations need masses of order 10 TeV, while the other
superpartners need masses less than 1 TeV. Therefore, the mass spectrum in our
model is one example of the `effective supersymmetry' model proposed by Cohen,
Kaplan and Nelson.


title: QCD Sum Rule Analysis of B \to (K,K^*) (\ell^+\ell^-,\nu\bar\nu) Decays

abstract:
  We use three-point QCD sum rules to calculate the form factors governing the
rare exclusive decays B \to (K,K^*) \ell^+ \ell^-, B \to (K,K^*) \nu \bar\nu.
We predict the branching ratios, the invariant mass distributions of the lepton
pair for B \to (K,K^*) \ell^+ \ell^-, and the spectra of missing energy for B
\to (K,K^*) \nu \bar\nu. The forward-backward asymmetry in B \to K^* \ell^+
\ell^- provides us with interesting tests of the Standard Model and its
extensions.


title: Strange Particle Freeze-Out

abstract:
  We reconsider thermal conditions of the central fireball presumed to be the
source of abundantly produced strange (anti-)baryons in S -> W collisions at
200 GeV A. We show that it is possible to completely fix the freeze-out
temperature of strange particles in terms of the central rapidity kaon to
Lambda particle abundance ratio at fixed, high transverse mass using a
non-equilibrium hadronization model and the measured quark fugacities.


title: Strange Particle Abundance in QGP Formed in 200 GeV A Nuclear Collisions

abstract:
  We investigate here the relative abundance of strange particles produced in
nuclear collisions at the SPS energies (9 GeV A in CM frame) assuming that the
central reaction fireball consists of quark-gluon plasma. We show that the
total strangeness yield in S-S, S-Ag and S-W reactions is compatible with this
picture.


title: Gluon production, cooling and entropy in nuclear collisions

abstract:
  We study the cooling (heating) of a glue-parton gas due to production
(destruction) of particles and determine the associated production of entropy.
We incorporate sharing of the system energy among a changing number of
particles. We find that the entropy of an evolving glue-parton gas changes in
an insignificant range once the initial high temperature state has been formed,
despite a great change in particle number and temperature.


title: QCD_2 in the modified Fock-Schwinger gauge

abstract:
  The system of light quark and heavy antiquark source is studied in 1+1 QCD in
the large N_C limit. The situation is demonstrated to be the two dimensional
analogue of the problem in 3+1 QCD corresponding to the essentially nonlocal
case of zero vacuum correlation length, which does not allow perturbative
treatment. The modified Fock-Schwinger gauge condition is employed to derive
the effective Dirac-type equation for the spectrum, which is proved to be
equivalent to the 't Hooft equation in the limit of one heavy mass. The chiral
condensate is shown to appear naturally in the given approach and to coincide
with the convenient value.


title:
Atmospheric Neutrino Oscillation and Large Lepton-Flavour Violation in
  the SUSY SU(5) GUT

abstract:
  The atmospheric neutrino anomaly reported by the super-Kamiokande
collaboration suggests existence of a large flavour violating Yukawa coupling
in the lepton sector. We discuss lepton-flavour violation at low energies in
the framework of the supersymmetric SU(5)_{GUT} model with right-handed
neutrinos. We find that for a wide range of parameter space suggested from the
atmospheric neutrino anomaly, if the tau-neutrino Yukawa coupling is as large
as that of top quark, lower bounds of the branching ratios of mu -> e gamma,
tau -> mu gamma, and the mu-e conversion rate on $^{48}_{22}Ti$ become around
10^{-14}, 10^{-9}, and 10^{-16}, respectively. These reaction rates may be in
the region accessible by near future experiments.


title: Evidence for a high entropy phase in nuclear collisions

abstract:
  We determine the entropy per baryon content of the central reaction region in
terms of the charged particle multiplicity. We study the consistency of our
findings with recent data on strange anti-baryon production at 200 GeV A in S
-> A collisions (A=200) assuming formation of a central fireball. Hadron gas
models which do not invoke strong medium modifications of hadron masses do not
provide enough entropy and are inconsistent with the combined experimental
results. In contrast the quark-gluon plasma hypothesis explains them naturally.


title: Strange anti-baryons - QGP versus HG

abstract:
  We study quark-gluon plasma (QGP) and hadronic gas (HG) models of the central
fireball presumed to be the source of abundantly produced strange
(anti-)baryons in S -> W collisions at 200 GeV A. We consider how multi-strange
(anti-)baryon multiplicities depend on strangeness conservation and compare the
HG and QGP fireball scenarios. We argue that the total particle multiplicity
emerging from the central rapidity region as well as the variation of
production rates with changes in the beam energy allows to distinguish between
the two reaction scenarios.


title: Hot hadronic matter and strange anti-baryons

abstract:
  We demonstrate that both quark-gluon plasma (QGP) and hadronic gas (HG)
models of the central fireball created in S -> W collisions at 200 GeV A are
possible sources of the recently observed strange (anti-) baryons. From the
theoretical point of view, the HG interpretation we attempt remains more
obscure because of the high fireball temperature required. The thermal
properties of the fireball as determined by the particle ratios, are natural
for the QGP state. We show that the total particle multiplicity emerging from
the central rapidity region allows to distinguish between the two scenarios.


title: Leptoquarks and the HERA High-Q2 Events

abstract:
  The excess of high-Q2 events recently observed in deep-inelastic
positron-proton scattering at HERA has refuelled speculations on physics beyond
the standard model, in particular on low-mass leptoquark-type particles. We
review the theoretical framework for leptoquark interactions, and their
production and decay at HERA. Bounds on leptoquark masses and couplings, and
implications on other experiments are also discussed.


title:
Target Fragmentation at Polarized HERA: A Test of Universal Topological
  Charge Screening in QCD

abstract:
  Topological charge screening has been proposed as the mechanism responsible
for the anomalous suppression in the first moment of the polarized proton
structure function -- the `proton spin' effect. An immediate consequence is
that this suppression should be target-independent, since the screening is a
fundamental property of the QCD vacuum. Here, we study the possibility of
testing the target-independent suppression in semi-inclusive target
fragmentation processes at polarized HERA.


title: D+- and D0 (anti D0) production asymetries in pion-proton collisions

abstract:
  We use a two-component model to describe the production mechanism of D mesons
in pi-p collisions. The model combines the usual QCD processes plus
fragmentation and recombination of charm that has been produced by
nonperturbative QCD mechanisms. A hard charm component in the pion must be
responsible of the particle anti-particle production asymmetries observed.


title:
Parton distributions in the photon from $\gamma^* \gamma$ and $\gamma^*
  p$ scattering

abstract:
  Leading order parton distributions in the photon are extracted from the
existing $F_2^\gamma$ measurements and the low-$x$ proton structure function.
The latter is related to the photon structure function by assuming Gribov
factorization to hold at low $x$. The resulting parton distributions in the
photon are found to be consistent with the Frankfurt-Gurvich sum rule for the
photon.


title:
Novel Electroweak Symmetry Breaking Conditions From Quantum Effects In
  The MSSM

abstract:
  We present, in the context of the Minimal Supersymmetric Standard Model, a
detailed one-loop analytic study of the minimization conditions of the
effective potential in the Higgs sector.
  Special emphasis is put on the role played by $Str M^4$ in the determination
of the electroweak symmetry breaking conditions, where first and second order
derivatives of the effective potential are systematically taken into account.
Novel, necessary (and sufficient in the Higgs sector) model-independent
constraints, are thus obtained analytically, leading to new theoretical lower
and upper bounds on $\tan \beta$. Although fully model-independent, these
bounds are found to be much more restrictive than the existing model-dependent
ones! A first illustration is given in the context of a SUGRA-GUT motivated
scenario.


title:
Determining the parameters of the Minimal Supergravity Model from 2l +
  E_T^{miss} + (jets) final states at LHC

abstract:
  We analyse the events with two same-flavour, opposite-sign leptons +
$E_T^{miss}$ + (jets) as expected in pp collisions at LHC within the framework
of the minimal Supergravity Model. The objective is the determination of the
parameters m_0 and m_{1/2} of this model (for a given value of $\tan\beta$).
The signature $l^+ l^- + E_T^{miss}$ + (jets) selects the leptonic decays of
$\tilde{\chi}^0_2$, $\tilde{\chi}^0_2 \to \tilde{\chi}^0_1 l^+ l^- $,
$\tilde{\chi}^0_2 \to \tilde{l}_{L,R}^{\pm} l^{\mp} \to \tilde{\chi}^0_1 l^+
l^-$. We exploit the fact that the invariant dilepton mass distribution has a
pronounced structure with a sharp edge at the kinematical endpoint even in such
an inclusive final state over a significant part of parameter space. We
determine the domain of parameter space where the edge is expected to be
visible. We show that a measurement of this edge already constrains the model
parameters essentially to three lines in the ($m_0, m_{1/2}$) parameter plane.
We work out a strategy to discriminate between the three-body leptonic decays
of $\tilde{\chi}^0_2$ and the decays into sleptons $\tilde{l}_{L,R}$. This
procedure may make it possible to get information on SUSY particle masses
already with low luminosity, L_{int}=10^3 pb^{-1}.


title: An Introduction To Solar Neutrino Research

abstract:
  The first lecture describes the conflicts between the combined standard model
(minimal electroweak and solar) predictions and the results of solar neutrino
experiments. The second lecture discusses the possibilities for detecting with
solar neutrinos ``smoking gun'' indications of departures from minimal
electroweak theory. Viewgraphs and related data are available at
http://www.sns.ias.edu/~jnb .


title: Quark-Gluon Coupling in the Global Colour Model of QCD

abstract:
  The Global Colour Model of QCD is used in conjunction with a pure-gluon
lattice correlator (by Marenzoni et al.) to extract from meson data a
momentum-dependent quark-gluon coupling down to $s \approx 0.3 GeV^2$. This is
compared with a lattice calculation (by Skullerud) of the quark-gluon coupling.


title: Preheating in Hybrid Inflation

abstract:
  We investigate the possibility of preheating in hybrid inflation. This
scenario involves at least two scalar fields, the inflaton field $\phi$, and
the symmetry breaking field $\sigma$. We found that the behavior of these
fields after inflation, as well as the possibility of preheating (particle
production due to parametric resonance), depends crucially on the ratio of the
coupling constant $\lambda$ (self-interaction of the field $\sigma$) to the
coupling constant $g^2$ (interaction of $\phi$ and $\sigma$). For $\lambda \gg
g^2$, the oscillations of the field $\sigma$ soon after inflation become very
small, and all the energy is concentrated in the oscillating field $\phi$. For
$\lambda \sim g^2$ both fields $\sigma$ and $\phi$ oscillate in a rather
chaotic way, but eventually their motion stabilizes, and parametric resonance
with production of $\chi$ particles becomes possible. For $\lambda \ll g^2$ the
oscillations of the field $\phi$ soon after inflation become very small, and
all the energy is concentrated in the oscillating field $\sigma$. Preheating
can be efficient if the effective masses of the fields $\phi$ and $\sigma$ are
much greater than the Hubble constant, or if these fields are coupled to other
light scalar (or vector) fields $\chi$. In the recently proposed hybrid models
with a second stage of inflation after the phase transition, both preheating
and usual reheating are inefficient. Therefore for a very long time the
universe remains in a state with vanishing pressure. As a result, density
contrasts generated during the phase transition in these models can grow and
collapse to form primordial black holes. Under certain conditions, most of the
energy density after inflation will be stored in small black holes, which will
later evaporate and reheat the universe.


title: Working group on $\pi\pi$ and $\pi$N interactions - Summary

abstract:
  This is the summary of the working group on $\pi\pi$ and $\pi$N interactions
of the Chiral Dynamics Workshop in Mainz, September 1-5, 1997. Each talk is
represented by an extended one page abstract. Some additional remarks by the
convenors are added


title: Rare exclusive semileptonic b -> s transitions in the Standard Model

abstract:
  We study long-distance effects in rare exclusive semileptonic decays B -> (K,
K*) (l+ l-, nu bar{nu}) and analyze dilepton spectra and asymmetries within the
framework of the Standard Model. The form factors, describing the meson
transition amplitudes of the effective Hamiltonian are calculated within the
lattice-constrained dispersion quark model: the form factors are given by
dispersion representations through the wave functions of the initial and final
mesons, and these wave functions are chosen such that the B -> K* transition
form factors agree with the lattice results at large q**2. We calculate
branching ratios of semileptonic B -> K, K* transition modes and study the
sensitivity of observables to the long-distance contributions. The shape of the
forward-backward asymmetry and the longitudinal lepton polarization asymmetry
are found to be independent of the long-distance effects and mainly determined
by the values of the Wilson coefficients in the Standard Model.


title: Coherence of neutrino oscillations in the wave packet approach

abstract:
  The temporal and spatial coherence widths of the microscopic process by which
a neutrino is detected are incorporated in the quantum mechanical wave packet
treatment of neutrino oscillations, confirming the observation of Kiers,
Nussinov and Weiss that an accurate measurement of the energies of the
particles participating in the detection process can increase the coherence
length. However, the wave packet treatment presented here shows that the
coherence length has an upper bound, determined by the neutrino energy and the
mass-squared difference, beyond which the coherence of the oscillation process
is lost.


title:
CP Violation from Charged Higgs Exchange in Hadronic Tau Decays with
  Unpolarized Beams

abstract:
  CP violating signals in semileptonic $\tau$ decays induced by an exotic
scalar exchange are studied in a completely model-independent way. These can be
observed in decays of unpolarized single $\tau$'s even if their rest frame
cannot be reconstructed. No beam polarization is required. The importance of
the two-meson channel, in particular the $K\pi$ final state is emphasized.


title: Chiral nucleon dynamics

abstract:
  These lectures give an introduction to baryon chiral perturbation theory. I
show in detail how to construct the chiral effective pion-nucleon Lagrangian in
the one loop approximation. Particular emphasis is put on the physics related
to electromagnetic probes, as manifest in pion photo- and electroproduction,
Compton scattering off nucleons and the electroweak form factors of the
nucleon. Other topics discussed in some detail are the meaning of low-energy
theorems, pion-nucleon scattering, the reaction $\pi N \to \pi \pi N$ and
isospin violation in the pion-nucleon system. The chiral predictions are
confronted with the existing data. Some remaining problems and new developments
are outlined.


title: Jet Production in DIS at NLO Including Z and W Exchange

abstract:
  Next-to-leading order QCD predictions for 1-jet and 2-jet cross sections in
deep inelastic scattering with complete neutral current ($\gamma^*$ and $Z$)
and charged current ($W^\pm$) exchange are presented.


title:
Update of the electromagnetic effective coupling constant
  $\alpha(M^2_Z)$

abstract:
  We recalculate the hadronic contribution to the effective electromagnetic
coupling constant $\alpha(M^2_Z)$ using quasi-analytical approximations for the
cross-section of $e^{+}e^{-} \to hadrons$ proposed earlier by one of the
authors(N.V.K.,Mod.Phys.Lett.A9(1994)2825). We find that $\alpha^{-1}(M^2_Z) =
128.98 \pm 0.06$.


title:
Chiral Constituent quarks and their role in quark distribution functions
  of nucleon and pion

abstract:
  We investigate the structure of constituent quarks and study implications for
quark distribution functions of hadrons. Constituent quarks are constructed by
dressing bare quarks with Goldstone bosons using the chiral quark model. We
calculate resulting corrections to the twist-2 structure functions $f_1(x)$,
$g_1(x)$ and $h_1(x)$. The Goldstone boson fluctuations produce a flavor
asymmetry of the quark distribution in the nucleon in agreement with
experimental data. They also generate significant depolarization effects which
reduce the fraction of the nucleon spin carried by quarks. Corrections to the
transversity spin structure function $h_1(x)$ differ from those to $g_1(x)$,
and in particular we find a large reduction (40%) of the $d$-quark tensor
charge, which is consistent with recent lattice calculations. We also study the
pion structure function and find the momentum fraction carried by the sea
quarks in the pion to be considerably larger than that in the nucleon.


title:
Mesonic Parton Densities Derived From Constituent Quark Model
  Constraints

abstract:
  Using constituent quark model constraints we calculate the gluon and sea
content of pions solely in terms of their valence density and the known sea and
gluon densities of the nucleon. The resulting small-x predictions for
g^{pi}(x,Q^2) and \bar{q}^{pi}(x,Q^2) are unique and parameter free, being
entirely due to QCD dynamics. Similar ideas are applied for calculating the
gluon and sea content of kaons which, for our suggested choice of the kaon's
valence densities, turn out to be identical to the ones of the pion.


title: Renormalization Group Flow Equations for the Sigma Model

abstract:
  We present a nonperturbative renormalization group solution of the
Gell-Mann--Levy $\sigma$-model which was originally proposed as a
phenomenological description of the dynamics of nucleons and mesons. In our
version of the model the fermions are interpreted as quarks which interact via
the $\sigma$ and $\pi$ mesons. We derive and numerically solve renormalization
group (RG) flow equations to leading order in a derivative expansion to study
the behavior of the model as it evolves from high to low momentum scales. We
develop an expansion in chiral-symmetry-breaking which enables us to track this
symmetry breaking with the evolution of the scale. We use infrared observables
to constrain the phenomenology allowing predictions of other quantities such as
$\pi-\pi$ scattering lengths. The results show improvement over the tree level
calculation and are consistent with experiment and the results of alternate
theoretical approaches such as chiral perturbation theory and lattice gauge
theory.


title:
The effect of off-diagonal parton distributions in diffractive vector
  meson electroproduction

abstract:
  We present a simple physical description of the off-diagonal gluon
distribution g (x,x^\prime,Q^2) and splitting function P_{gg}(x,x^\prime) which
enter the amplitude for diffractive vector meson production. We study the
off-diagonal effects both on the evolution in Q^2 and on the input
distribution. We predict the ratio $R$ of the off-diagonal to the diagonal
gluon density, x^\prime g(x,x^\prime,Q^2)/xg(x, Q^2), as a function of the
kinematic variables.


title:
Detecting Scalar Higgs Bosons in the Next-to-Minimal Supersymmetric
  Standard Model at Future Linear Colliders

abstract:
  We analyze the possibility of detecting one of the three scalar Higgs bosons
in the next-to-minimal supersymmetric model at the future $e^+e^-$ linear
collider, by examining their productions via the Higgsstrahlung process. The
production cross sections of the three scalar Higgs bosons in $e^+e^-$
collisions are evaluated for the proposed c.m. energies of the future $e^+e^-$
colliders, for the whole space of relevant parameters. We find that at least
one of the three production cross sections is not smaller than 16 fb, 4 fb, and
1 fb for ${\sqrt s} = 500$ GeV, 1000 GeV, and 2000 GeV, respectively. Those
numbers indicate that at least one of the three scalar Higgs bosons in the
next-to-minimal supersymmetric model may be detected at the future $e^+e^-$
linear colliders via the Higgsstrahlung process.


title:
The polarised gluon density from di-jet events in DIS at a polarised
  HERA

abstract:
  We present a possible direct measurement of the polarised gluon density
$\Delta G(x)$ in LO from di-jet production in polarised deep inelastic ep
scattering, assuming the kinematics of the HERA collider. We show the
sensitivity to the x-dependence of $\Delta G(x)$ and to the first moment $\int
\Delta G(x) dx$ in the range $0.002< x <0.2$, assuming the electron and proton
beam of HERA being polarised to 70% and an integrated luminosity of at least
200 pb$^{-1}$. We include in our study hadronisation and higher order effects,
as well as realistic detector smearing and acceptance. We find that the
statistical and systematic uncertainties are small enough to distinguish
between different parametrizations for $\Delta G(x)$, which all are in
accordance with present data. We stress that at HERA an x-range could be
measured, that is not accessible to any other present or proposed experiment.


title: Recent Results on Neutrino Masses

abstract:
  I review the main options one has of introducing mass to neutrinos, including
broken R-parity models, as well as the constraints on neutrino properties that
follow from astrophysics, cosmology as well as laboratory observations.


title: Aspects of Quenched Chiral Perturbation Theory for Matter Fields

abstract:
  Three topics about the application of quenched chiral perturbation theory to
matter fields are studied. It is proved that the hairpin axial current
couplings in quenched chiral perturbation theories do not contribute to the
quenched chiral singularities for one chiral loop renormalization of matter
field properties. The modification of mass corrections in the chiral limit due
to nonzero mass splittings are studied, and selection rules for hadron decays
in quenched QCD are obtained.


title:
Mass and width of sigma(750) scalar meson from measurements of
  pi(-)p->pi(-)pi(+)n on polarized target

abstract:
  Model independent amplitude analyses of $\pi^- p_\uparrow \to \pi^- \pi^+ n$
on polarized target at 17.2 GeV/c reveal resonant structure of S-wave
transversity amplitudes $|\bar S|^2\Sigma$ and $|S|^2\Sigma$ near 750 MeV.
Simultaneous fit to $|\bar S|^2\Sigma$ and $|S|^2\Sigma$ with a single $\sigma$
pole yields $m_\sigma = 775 \pm 17$ MeV and $\Gamma_\sigma = 147 \pm 33$ MeV.
Simultaneous fit with two common $\sigma$ poles yields a lower $\chi^2/dpt$.
Their resonance parameters are $m_\sigma = 786 \pm 24$ MeV, $\Gamma_\sigma =
130 \pm 47$ MeV and $m_{\sigma^\prime} = 670 \pm 30$ MeV,
$\Gamma_{\sigma^\prime} = 59 \pm 58$ MeV.


title: Long Distance Contribution to $K_L \to \ell^+ \ell^-$

abstract:
  We revisit the calculation of the long distance contribution to $K_L \to
\mu^+ \mu^-$. We discuss this process within the framework of chiral
perturbation theory, and also using simple models for the $K_L \gamma^*
\gamma^*$ vertex. We argue that it is unlikely that this mode can be used to
extract information on short distance parameters. The process $K_L \to e^+ e^-$
is also long-distance dominated and we find that $B(K_L \to e^+ e^-) \approx 9
\times 10^{-12}$.


title: On the LEP Measurements of the Rising Photon-Photon Total Cross Section

abstract:
  Using vector meson dominance we calculate the $\gamma\gamma$ total cross
section from data on $pp$, $p\bar p$ and $\gamma p$ total cross sections. Our
result agrees with recent high energy measurements performed by the L3
experiment at the LEP collider, not with the conflicting preliminary data
obtained by OPAL.


title: Glueball Spectrum from the B.S. Equation

abstract:
  The mass of the glueballs is calculated in the B.S. equation framework. Under
instantaneous approximation, the wave function of B.S. equations are obtained.
The kernel is chosen as the sum of an one-gluon exchange potential, a contact
interaction and a linear confining potential. The numerical results are in
agreement with that of recent lattice calculation.


title: Pseudoscalar Glueball Mass: QCD vs. Lattice Gauge Theory Prediction

abstract:
  We study whether the pseudoscalar glueball mass in full QCD can differ from
the prediction of quenched lattice calculations. Using properties of the
correlator of the vacuum topological susceptibility we derive an expression for
the upper bound on the QCD glueball mass. We show that the QCD pseudoscalar
glueball is lighter than the pure Yang-Mills theory glueball studied in
quenched lattice calculations. The mass difference between those two states is
of order of $1/N_c$. The value calculated for the $0^{-+}$ QCD glueball mass
can not be reconciled with any physical state observed so far in the
corresponding channel. The glueball decay constant and its production rate in
$J/\psi$ radiative decays are calculated. The production rate is large enough
to be studied experimentally.


title: A Constraint on EHNS Parameters from Solar Neutrino Problem

abstract:
  We suppose that the solar neutrino problem is only due to the mechanism
introduced by Ellis, Hagelin, Nanopoulos and Srednicki (EHNS), then a lower
limit constraint on EHNS parameters is obtained. We find that gamma > 7.4
10^(-22)GeV if alpha < 2 gamma and alpha > 1.5 10^(-21)GeV if alpha > 2 gamma,
this limit is consistent with the upper limits extract from the K0-K0bar system
and can be detected in the future experiments.


title: Delta G(x) from high p_t hadrons in DIS at a polarised HERA

abstract:
  We investigate the possibility to identify photon-gluon fusion (PGF) events
in polarised deep inelastic ep scattering, assuming the kinematics of the HERA
collider, by a pair of charged high p_t particles. In a Monte Carlo study we
find possible selection criteria and show the expected measurable asymmetries.
We discuss the sensitivity to $\Delta G(x)$ and compare the result to the one
obtained using di-jets to tag PGF events.


title:
Hard diffraction and central diffraction in hadron-hadron and
  photon-hadron collisions

abstract:
  Hadron production in single and central diffraction dissociation is studied
in a model which includes soft hadron interaction as controlled by a
supercritical pomeron parametrization and hard diffraction. Within this model,
particle production in collisions with pomerons exhibit properties like
multiple soft interactions and multiple minijets, quite similar to hadron
production in non-diffractive hadronic collisions at high energies. However,
important differences occur in transverse momentum jet and hadron
distributions. It is shown that the model is able to describe data from the
CERN-SPS collider and from the HERA collider. Model predictions are presented
for single and central diffraction at TEVATRON.


title: Asymptotic Dynamics in Scalar Field Theory: Anomalous Relaxation

abstract:
  We analyze the dynamics of dissipation and relaxation in the unbroken and
broken symmetry phases of scalar theory in the nonlinear regime for large
initial energy densities, and after linear unstabilities (parametric or
spinodal) are shut-off by the quantum backreaction. A new time scale emerges
that separates the linear from the non-linear regimes. This scale is non-
perturbative in the coupling and initial amplitude. The non-perturbative
evolution is studied in the large the N limit for the O(N) vector model. A
combination of numerical analysis and the multitime scale analysis reveals the
presence of unstable bands in the nonlinear regime. These are associated with
power law growth of quantum fluctuations, that result in power law relaxation
and dissipation with non-universal and non-perturbative dynamical anomalous
exponents.We find substantial particle production during this non-linear evolu-
tion which is of the same order as that in the linear regime. The expectation
value of the scalar field vanishes asymptotically transferring all of the
initial energy into produced particles via the non-linear resonances in the
unbroken symmetry phase.The effective mass for the quantum modes tends asympto-
tically to a constant plus oscillating O(1/t) terms. This slow decay causes the
power behaviour in the modes which become free for t=infty. We derive a simple
expression for the equation of state for the fluid of produced particles that
interpolates between radiation-type and dust-type equations according to the
initial value of the order parameter for unbroken symmetry. For broken symmetry
the produced particles are massless Goldstone bosons with a radiation-type
equation of state. We find the onset of a novel form of dynamical Bose
condensation in the collisionless regime in the absence of thermalization.


title:
Tests for a Strong Electroweak Sector at Future e^+e^- High Energy
  Colliders

abstract:
  The study of the scattering at high energy of the gauge bosons W and Z, in
particular longitudinally polarized W and Z, can clarify the mechanism of
spontaneous symmetry breaking in the Standard Model of the electroweak
interactions. Different models of strong electroweak sector, based on the
effective lagrangian approach are briefly reviewed. They include models with no
resonance, with scalar resonance, additional vector and axial-vector
resonances. The effective Lagrangians are derived from the chiral symmetry of
the symmetry breaking sector. Limits on these models from existing
measurements, mainly LEP and Tevatron, are considered. We study also direct and
indirect effects of the new interactions at high energy future e^+e^- linear
colliders, through WW scattering and the direct production of these new vector
gauge bosons.


title: Theoretical Aspects of Heavy Flavour Physics

abstract:
  I review the status of theoretical aspects of B-decays. The principal
difficulty in interpreting the wealth of experimental data is the control of
non-perturbative QCD effects, and the talk is focused on attempts to control
these effects. Lattice results for the decay constants, B-$\bar B$ mixing and
semileptonic form-factors are summarized. The discrepancy of the theoretical
predictions and experimental measurements for the ratio of lifetimes
$\tau(\Lambda_b)/\tau(B_0)$ is discussed, as well as the status of the
semileptonic branching ratio of the B-meson. The difficulties in making
quantitative predictions for exclusive nonleptonic decays are stressed, and
some recent approaches to this problem are outlined.


title:
QCD Analysis of Unpolarized and Polarized Lambda - Baryon Production in
  Leading and Next-to-Leading Order

abstract:
  We analyze experimental data for the production of Lambda baryons in e^+e^-
annihilation in terms of scale dependent, QCD evolved, Lambda fragmentation
functions. Apart from the vast majority of the data for which the polarization
of an observed Lambda was not determined, we also consider the recent LEP
measurements of the longitudinal polarization of Lambda's produced on the
Z-resonance. Such data correspond to spin-dependent fragmentation functions for
the Lambda. We point out that the present data are insufficient to
satisfactorily fix these. We therefore suggest several different sets of
fragmentation functions, all compatible with present data, and study the
prospects for conceivable future semi-inclusive deep-inelastic scattering
experiments to discriminate between them. We provide the complete
next-to-leading order QCD framework for all the processes we consider.


title: Anti-Grand Unification and Critical Coupling Universality

abstract:
  The present work considers the phase transition between the confinement and
"Coulomb" phases in U(1), SU(2) and SU(3)-sectors of Anti-grand unified theory
described by regularized Wilson loop action. It was shown the independence of
the critical coupling constants of the regularization method ("universality").


title: A Baryon Model in Covariant Constraint Dynamics

abstract:
  An important ingredient of parton or string cascade models for
ultrarelativistic heavy-ion reactions is a parton description of the baryon.
Whereas previous models needed the concept of a diquark in an essential way, we
have developed a new model using Dirac's approach of Poincare-covariant
many-body dynamics with constraints.
  In our model, the baryon is described as a dynamical set of three valence
quarks and a fourth 'particle', the "junction", which carries the momentum
fraction of the sea quarks as well as all of the glue.
  The model's parameters are the quark current masses, and one interaction
strength, determined by the proton radius. Thus the model has no adjustable
free parameters. Nevertheless, we obtain a remarkably good fit to the valence
quark structure functions of the baryon


title: The Effective QCD Lagrangian and Renormalization Group Approach

abstract:
  The perturbative part of the effective QCD Lagrangian was constructed by the
renormalization group approach in the 4-loop approximation. It was extrapolated
in the non-perturbative region under the assumption of the existence of gluon
condensate at (F_{\mu\nu}^j)^2=F_0^2. The best result is F_0^2\approx 0.4
GeV^4.


title: Asymptotic expansion of Feynman integrals near threshold

abstract:
  We present general prescriptions for the asymptotic expansion of massive
multi-loop Feynman integrals near threshold. As in the case of previously known
prescriptions for various limits of momenta and masses, the terms of the
threshold expansion are associated with subgraphs of a given graph and are
explicitly written through Taylor expansions of the corresponding integrands in
certain sets of parameters. They are manifestly homogeneous in the threshold
expansion parameter, so that the calculation of the given Feynman integral near
the threshold reduces to the calculation of integrals of a much simpler type.
The general method is illustrated by two-loop two-point and three-point
diagrams. We discuss the use of the threshold expansion for problems of
physical interest, such as the next-to-next-to-leading order heavy quark
production cross sections close to threshold and matching calculations and
power counting in non-relativistic effective theories.


title: Perturbative Universality in Soft Particle Production

abstract:
  The spectrum of partons in a QCD jet becomes independent of the primary
energy in the low momentum limit. This follows within the perturbative QCD from
the colour coherence in soft gluon branching. Remarkably, the hadrons follow
such behaviour closely, suggesting the parton hadron duality picture to be
appropriate also for the low momentum particles. More generally, this scaling
property holds for particles of low transverse and arbitrary longitudinal
momentum, which explains an old experimental observation (``fan invariance'').
Further tests of the perturbatively based picture for soft particle production
are proposed for three-jet events in e+e- annihilation and di-jet production
events in gamma p, gamma-gamma and p\bar p collisions. They are based upon the
difference in the intensity of the soft radiation from primary q\bar q and gg
antennae.


title:
A Model for the Quark Mass and Flavor Mixing Matrices Based on Discrete
  Chiral Symmetry as the Origin of Families

abstract:
  We construct a model for the quark mass and flavor mixing matrices, based on
the hypothesis that the flavor weak eigenstates in the three families are
distinguished by a spontaneously broken discrete $Z_6$ chiral symmetry. In a
leading partially symmetric approximation, the model accommodates the family
mass spectra, with a CKM matrix that is exactly unity. Adding small asymmetries
in first order perturbation theory gives a CKM matrix with the correct
qualitative structure, with $s_{23}/s_{12}$ and $s_{13}/s_{12}$ naturally of
order $M_s/M_b$.


title: Higgs Production and Decay at Future Machines

abstract:
  Higgs boson production at future colliders within the Standard Model and its
minimal supersymmetric extension is reviewed. The predictions for decay rates
and production cross sections are presented including all relevant higher-order
corrections.


title:
QCD at Finite Baryon Density: Nucleon Droplets and Color
  Superconductivity

abstract:
  We use a variational procedure to study finite density QCD in an
approximation in which the interaction between quarks is modelled by that
induced by instantons. We find that uniform states with conventional chiral
symmetry breaking have negative pressure with respect to empty space at all but
the lowest densities, and are therefore unstable. This is a precisely defined
phenomenon which motivates the basic picture of hadrons assumed in the MIT bag
model, with nucleons as droplets of chiral symmetry restored phase. At all
densities high enough that the chirally symmetric phase fills space, we find
that color symmetry is broken by the formation of a <qq> condensate of quark
Cooper pairs. A plausible ordering scheme leads to a substantial gap in a
Lorentz scalar channel involving quarks of two colors, and a much smaller gap
in an axial vector channel involving quarks of the third color.


title: Diquark Bose Condensates in High Density Matter and Instantons

abstract:
  Instantons lead to strong correlations between up and down quarks with spin
zero and anti-symmetric color wave functions. In cold and dense matter,
$n_b>n_c\simeq 1 fm^{-3}$ and $T<T_c\sim$ 50 MeV, these pairs Bose-condense,
replacing the usual $< \bar qq >$ condensate and restoring chiral symmetry. At
high density, the ground state is a color superconductor in which diquarks play
the role of Cooper pairs. An interesting toy model is provided by QCD with two
colors: it has a particle-anti-particle symmetry which relates $<\bar qq>$ and
$< qq>$ condensates.


title: Photon Scattering in Muon Collisions

abstract:
  We estimate the benefit of muon colliders for photon physics. We calculate
the rate at which photons are emitted from muon beams in different production
mechanisms. Bremsstrahlung is reduced, beamstrahlung disappears, and laser
backscattering suffers from a bad conversion of the incoming to the outgoing
photon beam in addition to requiring very short wavelengths. As a consequence,
the cross sections for jet photoproduction in $\mu p$ and $\mu^+\mu^-$
collisions are reduced by factors of 2.2 and 5 compared to $ep$ and $e^+e^-$
machines. However, the cross sections remain sizable and measurable giving
access to the photon and proton parton densities down to $x$ values of
$10^{-3}$ to $10^{-4}$.


title:
Can Theta/N Dependence for Gluodynamics be Compatible with 2 pi
  Periodicity in Theta ?

abstract:
  In a number of field theoretical models the vacuum angle \theta enters
physics in the combination \theta/N, where N stands generically for the number
of colors or flavors, in an apparent contradiction with the expected 2 \pi
periodicity in \theta. We argue that a resolution of this puzzle is related to
the existence of a number of different \theta dependent sectors in a finite
volume formulation, which can not be seen in the naive thermodynamic limit V ->
\infty. It is shown that, when the limit V -> \infty is properly defined,
physics is always 2 \pi periodic in \theta for any integer, and even rational,
values of N, with vacuum doubling at certain values of \theta. We demonstrate
this phenomenon in both the multi-flavor Schwinger model with the bosonization
technique, and four-dimensional gluodynamics with the effective Lagrangian
method. The proposed mechanism works for an arbitrary gauge group.


title: New Physics Signatures in Dijets at Hadron Colliders

abstract:
  We show how to detect and disentangle at the upgraded Tevatron and at LHC,
the effects of the three purely gluonic $dim=6$ $SU(3)\times SU(2) \times U(1)$
CP-conserving and CP-violating gauge invariant operators $\ol{\O}_{DG}$, $\O_G$
and $\wtil{\O}_{G}$. These operators are inevitably generated by New Physics
(NP), if the heavy particles responsible for it are coloured. We establish the
relations between their coupling constants and the corresponding NP scales
defined through the unitarity relations. We then study the sensitivity and
limits obtainable through production processes involving one or two jets, and
express these limits in terms of the NP scales implied by unitarity. A detailed
comparison with the results of the studies of the analogous electroweak
operators, is also made.


title: Neutrino oscillation constraints on neutrinoless double beta decay

abstract:
  We have studied the constraints imposed by the results of neutrino
oscillation experiments on the effective Majorana mass |<m>| that characterizes
the contribution of Majorana neutrino masses to the matrix element of
neutrinoless double-beta decay. We have shown that in a general scheme with
three Majorana neutrinos and a hierarchy of neutrino masses (which can be
explained by the see-saw mechanism), the results of neutrino oscillation
experiments imply rather strong constraints on the parameter |<m>|. From the
results of the first reactor long-baseline experiment CHOOZ and the Bugey
experiment it follows that |<m>| < 3x10^{-2} eV if the largest mass-squared
difference is smaller than 2 eV^2. Hence, we conclude that the observation of
neutrinoless double-beta decay with a probability that corresponds to |<m>| >
10^{-1} eV would be a signal for a non-hierarchical neutrino mass spectrum
and/or non-standard mechanisms of lepton number violation.


title: Two Lectures on FCNC and CP Violation in Supersymmetry

abstract:
  These two lectures constitute a reappraisal and an update of the status of
the Flavour Changing Neutral Current (FCNC) and CP violation issues in
supersymmetry. The first lecture discusses these points in the framework of the
Minimal Supersymmetric Standard Model (MSSM), while the second one provides an
analysis in a generic low-energy supersymmetric extension of the Standard
Model. The goal of these lectures is twofold: on one hand we present a
qualitative and quantitative discussion of the threat that FCNC and CP
violation represent on supersymmetry model building; on the other hand, we
point out how precious FCNC and CP violation may be in obtaining some signals
of the presence of supersymmetry at low energy in the years that separate us
from the advent of LHC physics. In particular, concerning this latter point, we
emphasize and thoroughly analyze the role of experimental searches for rare B
decays and CP violation in B physics.


title:
Next-to-Leading Order QCD Corrections to $\Delta F =2$ effective
  Hamiltonians

abstract:
  The most general QCD next-to-leading anomalous-dimension matrix of all
possible four-fermion, dimension-six $\Delta F=2$ operators is computed. The
results of this calculation can be used in many phenomenological applications,
among which the most important are those related to theoretical predictions of
$K^0-\bar{K}^0 $ and $B^0-\bar{B}^0$ mixing in several extension of the
Standard Model (Supersymmetry, left-right symmetric, multi-Higgs models, etc.),
to estimates of the $B^0_s$--$\bar B^0_s$ width difference, $\Delta
\Gamma_{B_s}$, and to the calculation of the $O(1/m_b^3)$ corrections for
inclusive b-hadron decay rates.


title: Investigations into the BFKL Mechanism with a Running QCD Coupling

abstract:
  We present approximations of varying degree of sophistication to the integral
equations for the (gluon) structure functions of a hadron (``the partonic flux
factor'') in a model valid in the Leading Log Approximation with a running
coupling constant. The results are all of the BFKL-type, i.e. a power in the
Bjorken variable x_B^{-\lambda} with the parameter \lambda determined from the
size \alpha_0 of the ``effective'' running coupling \bar{\alpha}\equiv
3\alpha_s/\pi= \alpha_0/\log(k_{\perp}^2) and varying depending upon the
treatment of the transverse momentum pole. We also consider the implications
for the transverse momentum (k_{\perp}) fluctuations along the emission chains
and we obtain an exponential falloff in the relevant \kappa\equiv
\log(k_{\perp}^2)-variable, i.e. an inverse power (k_{\perp}^2)^{-(2+\lambda)}
with the same parameter \lambda. This is different from the BFKL-result for a
fixed coupling, where the distributions are Gaussian in the \kappa-variable
with a width as in a Brownian motion determined by ``the length'' of the
emission chains, i.e. \log(1/x_B). The results are verified by a realistic
Monte Carlo simulation and we provide a simple physics motivation for the
change.


title: Flavoring of Pomeron and Diffractive Production at Tevatron Energies

abstract:
  The most important consequence of Pomeron being a pole is the factorization
property. However, due to Pomeron intercept being greater than 1, the
extrapolated single diffraction dissociation cross section based on a classical
triple-Pomeron formula is too large leading to a potential unitarity violation
at Tevatron energies. It is our desire here to point out that the "flavoring"
of Pomeron plays the dominant role in resolving this apparent "paradox".


title:
Twist-2 Light-Ray Operators: Anomalous Dimensions and Evolution
  Equations

abstract:
  The non-singlet and singlet anomalous dimensions of the twist--2 light-ray
operators for unpolarized and polarized deep inelastic scattering are
calculated in $O(\alpha_s)$. We apply these results for the derivation of
evolution equations for partition functions, structure functions, and wave
functions which are defined as Fourier transforms of the matrix elements of the
light-ray operators. Special cases are the Altarelli-Parisi and Brodsky-Lepage
kernels. Finally we extend Radyushkin's solution from the non-singlet to the
singlet case.


title:
Renormalization-scale-invariant continuation of truncated QCD (QED)
  series -- an analysis beyond large-beta_0 approximation

abstract:
  An approximation algorithm is proposed to transform truncated QCD (or QED)
series for observables. The approximation is a modification of the Baker-Gammel
approximants, and is independent of the renormalization scale (RScl) $\mu$ --
the coupling parameter $\alpha(\mu)$ in the series and in the resulting
approximants can evolve according to the perturbative renormalization group
equation (RGE) to any chosen loop order. The proposed algorithm is a natural
generalization of the recently proposed method of diagonal Pad\'e approximants,
the latter making the result RScl-invariant in large-$\beta_0$ approximation
for ${\alpha}(\mu)$. The algorithm described below can extract large amount of
information from a calculated available truncated perturbative series for an
observable, by implicitly resumming large classes of diagrams.


title: MSSM Higgs Boson Production at the LHC

abstract:
  The theoretical status of Higgs boson production at the LHC within the
minimal supersymmetric extension of the Standard Model is reviewed. The focus
will be on the evaluation of higher-order corrections to the production cross
sections and their phenomenological implications.


title: Squark and Gluino Production at Hadron Colliders

abstract:
  The theoretical status of squark and gluino production at present and future
hadron colliders is reviewed. I shall concentrate on the evaluation of SUSY-QCD
corrections to the production cross sections and their phenomenological
implications.


title:
Has the general two-Higgs-doublet model unnatural FCNC suppression? An
  RGE analysis

abstract:
  There is a widespread belief that the general two-Higgs-doublet model (G2HDM)
behaves unnaturally with respect to evolution of the flavor-changing neutral
Yukawa coupling parameters (FCNYCP's) -- i.e., that the latter, although being
suppressed at low energies of probes, in general increase by a large factor as
the energy of probes increases. We investigate this, by evolving Yukawa
parameters by one-loop renormalization group equations (RGE's) and neglecting
contributions of the first quark generation. For patterns of FCNYCP suppression
at low energies suggested by the existing quark mass hierarchies, FCNYCP's
remain remarkably stable (suppressed) up to energies very close to the Landau
pole. This indicates that G2HDM preserves FCNYCP suppression, for reasonably
chosen patterns of that suppression at low energies.


title: Higgs Bosons Strongly Coupled to the Top Quark

abstract:
  Several extensions of the Standard Model require the burden of electroweak
symmetry breaking to be shared by multiple states or sectors. This leads to the
possibility of the top quark interacting with a scalar more strongly than it
does with the Standard Model Higgs boson. In top-quark condensation this
possibility is natural. We also discuss how this might be realized in
supersymmetric theories. The properties of a strongly coupled Higgs boson in
top-quark condensation and supersymmetry are described. We comment on the
difficulties of seeing such a state at the Tevatron and LEPII, and study the
dramatic signatures it could produce at the LHC. The four top quark signature
is especially useful in the search for a strongly coupled Higgs boson. We also
calculate the rates of the more conventional Higgs boson signatures at the LHC,
including the two photon and four lepton signals, and compare them to
expectations in the Standard Model.


title:
Critical Dynamics of Symmetry Breaking: Quenches, Dissipation and
  Cosmology

abstract:
  Symmetry-breaking phase transitions may leave behind topological defects
\cite{Kibble} with a density dependent on the quench rate \cite{Zurek}. We
investigate the dynamics of such quenches for the one-dimensional,
Landau-Ginzburg case and show that the density of kinks, $n$, scales
differently with the quench timescale, $\tau_Q$, depending on whether the
dynamics in the vicinity of the critical point is overdamped ($n \propto
\tau_Q^{-1/4}$) or underdamped ($n \propto \tau_Q^{-1/3}$). Either of these
cases may be relevant to the early Universe, and we derive bounds on the
initial density of topological defects in cosmological phase transitions.


title:
Probing CP violation with time integrated decay rates into non-CP
  eigenstates

abstract:
  Many of the experiments proposed to look for interference CP violation in
neutral B mesons concentrate on tagged decay into CP eigenstates. Aleksan,
Dunietz, Kayser and Le Diberder have shown that one can also look for
interference CP violation using tagged decays into non-CP eigenstates. In all
these methods, one must trace the time dependence of the decays. In this
article we discuss a new method to search for interference CP violation by
using only time integrated rates into non-CP eigenstates. The method hinges on
the comparison between the decays of $\Upsilon(4S)$ into $f f$, $\bar{f}
\bar{f}$, and $f \bar{f}$, and also uses the rates for $l^+ f$ and $l^- f$.
This method does not depend on how the $\Upsilon(4S)$ is produced; provided
enough statistics, one can use both symmetric and asymmetric colliders.


title:
Polarization Asymmetry Zero in Heavy Quark Photoproduction and
  Leptoproduction Cross Sections

abstract:
  We demonstrate two novel features of the sea-quark contributions to the
polarized structure functions and photoproduction cross sections, a zero sum
rule and a zero crossing point of the polarization asymmetry, which can be
traced directly to the dynamics of the perturbative tree-graph gluon-splitting
contributions. In particular, we show that the Born contribution of massive
quarks arising from photon-gluon fusion gives zero contribution to the
logarithmic integral over the polarization asymmetry $\int {d\nu \over
\nu}\Delta \sigma(\nu,Q^2)$ for any photon virtuality. The vanishing of this
integral in the Bjorken scaling limit then implies a zero gluon-splitting Born
contribution to the Gourdin-Ellis-Jaffe sum rule for polarized structure
functions from massive sea quarks. The vanishing of the polarization asymmetry
at or near the canonical position predicted by perturbative QCD provides an
important tool for verifying the dominance of the photon-gluon fusion
contribution to charm photoproduction and for validating the effectiveness of
this process as a measure of the gluon polarization $\Delta G(x,Q^2)$ in the
nucleon. The displacement of the asymmetry zero from its canonical position is
sensitive to the virtuality of the gluon in the photon-gluon fusion subprocess,
and it can provide a measure of intrinsic and higher-order sea quark
contributions.


title: R-Parity Violation and Sneutrino Resonances at Muon Colliders

abstract:
  In supersymmetric models with R-parity violating interactions, sneutrinos may
be produced as $s$-channel resonances at $\mu^+ \mu^-$ colliders. We
demonstrate that, for R-parity violating couplings as low as $10^{-4}$,
sneutrinos can be discovered and their couplings measured to high accuracy. The
excellent beam energy resolution of muon colliders is found to be especially
useful for studying such resonances in certain cases.


title: CP Violation in Neutrinoless Double Beta Decay and Neutrino Oscillation

abstract:
  Taking account of possible CP violation, we discuss about the constraints on
the lepton mixing angles from the neutrinoless double beta decay and from the
neutrino oscillation for the three flavour Majorana neutrinos. From the CHORUS
oscillation experiment, combined with the data of neutrinoless double beta
decay, we show that the large angle solution of (\theta_{23}) is improbable if
the neutrino mass (m_3) of the third generation is a candidate of hot dark
matters.


title: Neutrino masses and mixing from neutrino oscillation experiments

abstract:
  We discuss which information on neutrino masses and mixing can be obtained
from the results of all neutrino oscillation experiments in the cases of three
and four massive neutrinos. We show that in the three-neutrino case the
neutrino oscillation data are not compatible with a hierarchy of couplings. In
the case of four neutrinos, a hierarchy of masses is disfavored by the data and
only two schemes with two pairs of neutrinos with close masses separated by a
gap of the order of 1 eV can accommodate the results of all experiments.


title:
SUSYGEN 2.2 - A Monte Carlo Event Generator for MSSM Sparticle
  Production at e+ e- Colliders

abstract:
  SUSYGEN is a Monte Carlo program designed for computing distributions and
generating events for MSSM sparticle production in e+ e- collisions. The
Supersymmetric (SUSY) mass spectrum may either be supplied by the user, or can
alternatively be calculated in two different models of SUSY Breaking: gravity
mediated supersymmetry breaking (SUGRA), and gauge mediated supersymmetry
breaking (GMSB). The program incorporates the most important production
processes and decay modes, including the full set of R-parity violating decays,
and the decays to the gravitino in GMSB models. Initial state radiation
corrections take into account pT/pL effects in the Structure Function
formalism, and an optimised hadronisation interface to JETSET 7.4 including
final state radiation is also provided.


title:
A study on Delta u and Delta d in charged current events using polarized
  beams at HERA

abstract:
  Charged current events are studied at HERA with polarized beams, using a
Monte Carlo event generator and taking into account detector smearing effects.
The observed asymmetries are used to study the extraction of the polarized
structure function g_5 and the polarized parton distributions $\Delta u$ and
$\Delta d$ in the proton.


title:
MSSM Radiative Corrections to the Top Pair Production Processes at
  Hadron Colliders

abstract:
  We calculate the MSSM $O(\alpha)$ corrections to the main production
processes of strong top pair production at the upgraded Tevatron and at the
LHC. In exploring the potential of future hadron colliders for performing
electroweak precision physics we study their effects on the total hadronic
cross sections, the invariant $t\bar t$ mass distributions and give first
results for parity violating asymmetries in the production of left and right
handed top quarks.


title: Higgs-Boson Low-Energy Theorem and Compatible Gauge-Fixing Conditions

abstract:
  Conventional gauge-fixing schemes such as R$_\xi$ gauges may lead to a
violation of the Higgs-boson low-energy theorem beyond the tree level. To
elucidate this fact, we study a simple model whose U(1) gauge symmetry is
spontaneously broken, and show how the Higgs-boson low-energy theorem can
consistently be extended to the gauge and Higgs sectors of the model. In this
formulation, any gauge-fixing condition must comply with the requirement that
it should be independent of the vacuum expectation value of the Higgs field in
the symmetric limit of the theory. We give a diagrammatic proof of the
Higgs-boson low-energy theorem to all orders in perturbation theory, within the
context of a judiciously modified R$_\xi$ gauge compatible with the above
constraint. The dependence of the kinematic parameters on the Higgs tadpole is
found to be very important for the proof of the theorem.


title:
Zenith distribution of atmospheric neutrino events and electron neutrino
  mixing

abstract:
  Assuming atmospheric neutrino oscillations with dominant nu_mu<--->nu_tau
transitions, we discuss how subdominant nu_e mixing (within the Chooz reactor
bounds) can alter the zenith distributions of neutrino-induced electrons and
muons. We isolate two peculiar distortion effects, one mainly related to nu_e
mixing in vacuum and the other to matter oscillations, that may be sufficiently
large to be detected by the SuperKamiokande atmospheric nu experiment. These
effects (absent for pure two-flavor nu_mu<--->nu_tau transitions) do not vanish
in the limit of energy-averaged oscillations.


title: On Event-by-Event Fluctuations in Nuclear Collisions

abstract:
  We demonstrate that a new type of analysis in heavy-ion collisions, based on
an event-by-event analysis of the transverse momentum distribution, allows us
to obtain information on secondary interactions and collective behaviour that
is not available from the inclusive spectra. Using a random walk model as a
simple phenomenological description of initial state scattering in collisions
with heavy nuclei, we show that the event-by-event measurement allows a
quantitative determination of this effect, well within the resolution
achievable with the new generation of large acceptance hadron spectrometers.
The preliminary data of the NA49 collaboration on transverse momentum
fluctuations indicate qualitatively different behaviour than that obtained
within the random walk model. The results are discussed in relation to the
thermodynamic and hydrodynamic description of nuclear collisions.


title: The Spin and Flavour Dependence of High-Energy Photoabsorption

abstract:
  We review the present data on high-energy, spin-dependent photoabsorption. We
find a strong isotriplet term in $(\sigma_A - \sigma_P)$ which persists from
$Q^2 \sim 0.25$GeV$^2$ to high $Q^2$ polarised deep inelastic scattering. For
$Q^2 \sim 4$GeV$^2$ and $x$ between 0.01 and 0.12 the isotriplet part of $g_1$
behaves as $g_1^{(p-n)} \sim x^{-{1 \over 2}}$, in contrast to soft Regge
theory which predicts that $g_1^{(p-n)}$ should converge as $x \to 0$. The
isotriplet, polarised structure function $2x g_1^{(p-n)}$ is significantly
greater than the isotriplet, unpolarised structure function $F_2^{(p-n)}$ in
this kinematic region. We analyse the low $Q^2$ photoabsorption data from E-143
and SMC and use this data to estimate the high-energy Regge contribution to the
Drell-Hearn-Gerasimov sum-rule.


title: Supernova neutrinos in the light of FCNC

abstract:
  We study the effect of including flavor changing neutral currents (FCNC) in
the analysis of the neutrino signal of a supernova burst. When we include the
effect of the FCNC which are beyond the standard model (SM) in the study of the
MSW resonant conversion, we obtain dramatic changes in the \Delta
m^2-sin^2(2\theta) probability contours for neutrino detection.


title: Solar Fluctuations and the MSW Effect

abstract:
  This talk summarizes the results of recent calculations of how fluctuations
within the solar medium can influence resonant neutrino oscillations within the
sun. Although initial calculations pointed to helioseismic waves as possibly
producing detectable effects, recent more careful calculations show this not to
be true. Those features of fluctuations which maximize their influence on
neutrino propagation are identified, and are likely to have implications for
supernovae and the early universe.


title: B and D Meson Decay Constants in Lattice QCD

abstract:
  We have calculated the decay constants of B and $D$ mesons with lattice QCD.
We use an $O(a)$ improved action that takes light quark actions as a starting
point, tuned so that it can be directly applied at the physical masses of the
$b$ and $c$ quarks. Our results are $f_B = 164 \err{+14}{-11} \pm 8$ MeV,
$f_{B_s} = 185 \err{+13}{-8} \pm 9$ MeV, $f_D = 194 \err{+14}{-10} \pm 10$ MeV,
and $f_{D_s} = 213 \err{+14}{-11} \pm 11$ MeV in the quenched approximation.
The first error in each case is statistical, and the second is from
perturbation theory. We show that discretization errors are under control in
our approach, and smaller than our statistical errors. The effects of the
quenched approximation may raise our quenched result by up to 10%.


title: Quark-antiquark contribution to the BFKL kernel

abstract:
  The quark-antiquark contribution to the BFKL kernel is calculated. Using the
effective vertex for the $q\bar q$ pair production in the Reggeon-Reggeon
collision we find this contribution by integrating the square of this vertex
over relative transverse momenta and fractions of longitudinal momenta of
produced particles.


title: A New Mechanism for $B^{\pm}\to \eta'K^{\pm}$ in Perturbative QCD

abstract:
  We present a new mechanism for $B^{\pm}\to \eta' K^{\pm}$, and analyze it
strictly within perturbative QCD. We find that such a new mechanism may
dominate non-leptonic $B$-decays to light mesons. Within a reasonable parameter
space, our prediction is in good agreement with the recent CLEO data on
$B^{\pm}\to \eta' K^{\pm}$. We conclude that there is no room for an abnormally
large \bsg vertex from physics beyond the Standard Model.


title:
Quartic Gauge Boson Couplings at Linear Colliders ---Interplay of
  WWZ/ZZZ Production and WW-Fusion--

abstract:
  We study new physics effects to the quartic gauge boson couplings formulated
by the electroweak chiral Lagrangian. Five next-to-leading order operators
characterize the anomalous quartic gauge interactions which involve pure
Goldstone boson dynamics for the electroweak symmetry breaking. We estimate the
typical size of these couplings in different strongly-interacting models and
examine the sensitivity to directly probing them via the WWZ/ZZZ triple gauge
boson production at the high energy linear colliders. The important roles of
polarized e- and e+ beams are stressed. We then compare the results with those
from the W-pair production of the WW-fusion processes, and analyze the
interplay of these two production mechanisms for an improved probe of the
quartic gauge boson interactions.


title: Particles and Nuclei as Quantum Slings

abstract:
  Rotation of such objects as an atomic nucleus or a chromodynamical string can
result in specific effects in scattering processes and multiparticle
production. Secondary fragments of the rotating nucleus or of the decaying
string can move like stones thrown from a sling. That would be detected as the
azimuthal asymmetry of particle distributions in individual events.
Non-classical states of the created particles like the Schr"\{o}dinger cats are
produced. Some classical and quantum-mechanical estimates of possible effects
are given. Experimental facts which can be used for their verification are
discussed.


title: Note on the Mass Square of the Eta' Meson

abstract:
  We propose to use as a mathematical tool to study the mass square of the
etaprime meson an infinitely heavy supplementary quark flavor Q. This is
understood in the framework of QCD with one light quark flavor (or n_fl light
flavors) and the gauge group SU3 colour (or SUN colour). The full system thus
consists of n_fl + 1 flavors, including the infinitely heavy one. The purpose
of this note is to show how the heavy flavor can be made to represent the
anomalies of the subtheory describing the remnant physical degrees of freedom.
In the large N_c limit the mass square of etaprime tends to a finite limit. The
essential deviations from (semi) perturbative derivations are related to simple
properties of the 'heavy' flavor.


title:
Constraints on long-baseline neutrino oscillations from the results of
  neutrino oscillation experiments

abstract:
  It is shown that in the two schemes with four massive neutrinos which are
compatible with the results of all neutrino oscillation experiments, the
probabilities of nu_e disappearance and nu_mu->nu_e appearance in long-baseline
experiments are severely constrained.


title:
Vacuum structure, spectrum of excitations and low-energy phenomenology
  in chiral preon-subpreon model of elementary particles

abstract:
  Inner and empirically consistent model of elementary particles, including two
matter structural levels beyond the quark one is built. Excitations spectra,
masses and interactions are analysed using the phenomenological notion of
non-pertubative vacuum condensate. Essential low-energy predictions of
developed concepts are classified.
  Effective gauge U(1)xU(1)xSU(2)-theory of quark-lepton excitations behavior
based on the performed analysis of preon-subpreon phenomenology is consistently
built. The ability of its expansion with fermions and scalar leptoquark
coupling is also considered. Shown that the coupling constants generation
hierarchy is the same as generation hierarchy of quark masses.
  Using the built theory cross-sections of d-quark-positron scattering
processes with both charged and neutral currents are calculated. The obtained
resonance peak is proposed to be a possible explanation of deviating from
Standard Model predictions discovered in DESY in the beginning of 1997 year.


title: QCD Corrections to Jet Production in Polarized $ep$ Scattering

abstract:
  Next-to-leading order QCD predictions for 1-jet and 2-jet cross sections in
polarized deep inelastic scattering at HERA energies are presented. Whereas the
QCD corrections to the total polarized cross section are very large, only
moderate corrections are found for the dijet cross sections.


title:
The Minimal Supersymmetric Standard Model with a Bilinear R--Parity
  Violating Term

abstract:
  Some aspects of bilinear R-Parity violation, the simplest extension of the
MSSM which does not conserve R-Parity, are reviewed in comparison with the
MSSM. We put special emphasis on the effect of quantum corrections.


title:
Single Charged and Neutral Supersymmetric Higgs Bosons Production with
  Jet at pp Colliders

abstract:
  In the framework of Minimal Supersymmetric Standard Model Higgs bosons
production via gluino/squark loop in the processes $gu \to H^{+}d$, $gd \to
H^{-}u$,$gq \to H^{0}_iq$ are studied.


title:
Multi-Loop Calculations in the Standard Model: Techniques and
  applications

abstract:
  We present a review of the Bielefeld-Dubna activities on the multiloop
calculations. In the first part a C-program DIANA (DIagram ANAlyser) for the
automation of Feynman diagram evaluations is presented, in the second part
various techniques for the evaluation of scalar diagrams are described, based
on the Taylor expansion method and large mass expansion.


title: Post-GZK Air Showers, FCNC, Strongly Interacting Neutrinos and Duality

abstract:
  A review is given on the recently proposed idea that air showers with energy
$> 10^{20}$ eV beyond the Greisen-Zatsepin-Kuz'min cut-off may be due to
neutrinos having acquired a strong interaction at these energies, as suggested
by the Dualized Standard Model. Such a hypothesis is shown to be consistent
with the so far known facts. Further, by linking the astrophysical puzzle of
post-GZK air showers through electric-magnetic duality to the problem of
fermion generations in particle physics, one obtains on the one hand estimates
for the rates of some flavour-changing neutral current decays which are
accessible to experiments being planned, and on the other direct tests on the
hypothesis performable by new air shower detectors such as Auger. The
suggestion does not exclude other explanations for post-GZK showers given in
the literature. However, we diagree with a recent paper by Burdman, Halzen and
Gandhi which sweepingly claimed to have excluded nearly all explanations by new
particle physics including ours.


title: Four-Fermion Production with Anomalous Couplings at LEP2 and NLC

abstract:
  I give a short report on the semi-analytical approach to off-shell W pair
production. In particular, I show the effects of irreducible background
diagrams of the CC11 class in the differential cross-section. Further, I study
the influence of potential anomalous couplings at a future linear collider and
investigate the sensitivity of the forward-backward asymmetry to anomalous
couplings.


title:
Next-to-Leading Order Analysis of Inclusive and Semi-inclusive Polarized
  Data

abstract:
  We present a combined next-to-leading order QCD analysis to data on both
inclusive and semi-inclusive polarized deep inelastic scattering asymmetries.
Performing NLO QCD global fits with different sets of observables, we evaluate
the impact of the very recent semi-inclusive results presented by SMC in the
extraction of NLO polarized parton distributions.


title: Decoupling of Supersymmetric Particles in the MSSM

abstract:
  A heavy supersymmetric spectrum at the Minimal Supersymmetric Standard Model
is considered and the decoupling from the low energy electroweak scale is
analyzed. A formal and partial proof of decoupling of supersymmetric particles
in the limit where their masses are larger than the electroweak scale is
performed by integrating out all the sparticles to one loop and by evaluating
the effective action for the standard electroweak gauge bosons $W^{\pm}, Z$ and
$\gamma$. The Higgs sector is not considered here. Analytical results for the
two-point functions of the electroweak gauge bosons and the $S, T$ and $U$
parameters, to be valid in that limit, are also presented. A discussion on how
the decoupling takes place in terms of both the physical sparticle masses and
the non-physical mass parameters as the $\mu$-parameter and the soft-breaking
parameters is included.


title: The QCD triple Pomeron coupling from string amplitudes

abstract:
  Using the recent solution of the triple Pomeron coupling in the QCD dipole
picture as a closed string amplitude with six legs, its analytical form in
terms of hypergeometric functions and numerical value are derived.


title: Colour-Octet Contributions to J/psi Production via Fragmentation at HERA

abstract:
  We study J/psi photoproduction via fragmentation at next-to-leading order in
the QCD-improved parton model, using the nonrelativistic factorization
formalism proposed by Bodwin, Braaten, and Lepage. We predict that measurements
of J/psi photoproduction at DESY HERA should show a distinctive excess over the
expectation based on the colour-singlet model at small values of the
inelasticity variable z.


title: Neutrino Physics in a Muon collider

abstract:
  A muon collider is expected to produce a high intensity neutrino beam which
is an admixture of either $\nu_{\mu}+\bar{\nu_e}$ or $\bar{\nu}_{\mu} +\nu_e$
which can can be directed to underground detectors far away from the source. It
will not only allow a probe of the $\nu_e-\nu_{\mu}$ as well as
$\nu_{\mu}-\nu_{\tau}$ oscillations in a range of mixing angle and $\Delta m^2$
not probed heretofore but it will also provide information about the mixing
angle $\theta_{e\tau}$ for a wide range of $\Delta m^2_{\nu_e\nu_{\tau}}$ from
$10^{-4}$ eV$^2$ to $10^{-1}$ eV$^2$ which cannot be obtained from any other
existing or proposed machine. One can also search for violations of Lorentz
invariance and deviations from equivalence principle for neutrinos at a level
which is three to four orders of magnitude more sensitive than possible at the
moment. This will test for instance some unorthodox suggestions to understand
both solar and atmospheric neutrinos using a single mass difference -squared
between the $\nu_e$ and $\nu_{\mu}$. It can also test various proposed models
neutrino masses and mixings to understand existing neutrino data.


title: P-odd observables at the $\Upsilon$ peak

abstract:
  We study the $\gamma$-Z interference in the process $e^+ e^-\to \Upsilon \to
\tau^+ \tau^-$ as a means to measure the neutral current coupling of the
b-quark. The helicity amplitudes are calculated from resonant and background
diagrams and the spin density matrix of the final state is discussed. The spin
analyzer of the $\tau$'s is illustrated with the decays $\pi \nu$ and $\rho \nu
\to (\pi \pi) \nu$. With $10^8 \Upsilon$ a sensitivity to $g_V^b$ of a few per
cent could be reachable.


title:
Search for Non-standard Higgs Boson in Diphoton Events at p pbar
  Collisions

abstract:
  We estimate the attainable limits on the coupling of a non-standard Higgs
boson to two photons taking into account the data collected by the Fermilab
collaborations on diphoton events. We based our analysis on a general set of
dimension--6 effective operators that give rise to anomalous couplings in the
bosonic sector of the Standard Model. If the coefficients of all ``blind''
operators are of the same order of magnitude, bounds on the anomalous triple
vector-boson couplings can also be obtained.


title:
A Complete Order-alpha**3 Calculation of the Cross Section for Polarized
  Compton Scattering

abstract:
  The construction of a computer code to calculate the cross sections for the
spin-polarized processes e-gamma=>e-gamma,e-gamma-gamma,e-e+e- to
order-alpha**3 is described. The code calculates cross sections for
circularly-polarized initial-state photons and arbitrarily polarized
initial-state electrons. The application of the code to the SLD Compton
polarimeter indicates that the order-alpha**3 corrections produce a fractional
shift in the SLC polarization scale of -0.1% which is too small and of the
wrong sign to account for the discrepancy in the Z-pole asymmetries measured by
the SLD Collaboration and the LEP Collaborations.


title: Constraints from Precision Electroweak Data on Leptoquarks and Bileptons

abstract:
  Explicit expressions are derived for the oblique parameters $S$ and $T$ in
certain extensions of the standard model. In particular, we consider
leptoquarks and bileptons, and find phenomenological constraints on their
allowed masses. Leptoquarks suggested by the neutral and charged current
anomalies at HERA can give improved agreement with both $S$ and $T$. If
bileptons are the only new states, the singly-charged one must be heavier than
the directly-established lower limit. Finally, we study SU(15) grand
unification and show that there are regions of parameter space where the theory
is compatible with experimental data.