title: Updated Analysis of a_1 and a_2 in Hadronic Two-body Decays of B Mesons

abstract:
  Using the recent experimental data of $B\to D^{(*)}(\pi,\rho)$, $B\to D^{(*)}
D_s^{(*)}$, $B\to J/\psi K^{(*)}$ and various model calculations on form
factors, we re-analyze the effective coefficients a_1 and a_2 and their ratio.
QCD and electroweak penguin corrections to a_1 from $B\to D^{(*)}D_s^{(*)}$ and
a_2 from $B\to J/\psi K^{(*)}$ are estimated. In addition to the
model-dependent determination, the effective coefficient a_1 is also extracted
in a model-independent way as the decay modes $B\to D^{(*)}h$ are related by
factorization to the measured semileptonic distribution of $B\to D^{(*)}\ell
\bar\nu$ at $q^2=m_h^2$. Moreover, this enables us to extract model-independent
heavy-to-heavy form factors, for example,
$F_0^{BD}(m_\pi^2)=0.66\pm0.06\pm0.05$ and
$A_0^{BD^*}(m_\pi^2)=0.56\pm0.03\pm0.04$. The determination of the magnitude of
a_2 from $B\to J/\psi K^{(*)}$ depends on the form factors $F_1^{BK}$,
$A_{1,2}^{BK^*}$ and $V^{BK^*}$ at $q^2=m^2_{J/\psi}$. By requiring that a_2 be
process insensitive (i.e., the value of a_2 extracted from $J/\psi K$ and
$J/\psi K^*$ states should be similar), as implied by the factorization
hypothesis, we find that $B\to K^{(*)}$ form factors are severely constrained;
they respect the relation $F_1^{BK}(m^2_{J/\psi})\approx 1.9
A_1^{BK^*}(m^2_{J/\psi})$. Form factors $A_2^{BK^*}$ and $V^{BK^*}$ at
$q^2=m^2_{J/\psi}$ inferred from the measurements of the longitudinal
polarization fraction and the P-wave component in $B\to J/\psi K^*$ are
obtained. A stringent upper limit on a_2 is derived from the current bound on
$\ov B^0\to D^0\pi^0$ and it is sensitive to final-state interactions.


title: New physics with mirror particles

abstract:
  The introduction of mirror fermions with masses between the weak scale and 1
TeV could offer a dynamical origin to the standard-model electro-weak symmetry
breaking mechanism. The purpose of this work is to study the dynamics needed in
order to render models with such a fermion content phenomenologically
acceptable.


title:
Decay rate asymmetry in $B \to X_s \gamma$ as a signature of
  supersymmetry

abstract:
  In the supersymmetric standard model, the radiative $B$-meson decay $B \to
X_s \gamma$ could receive a large contribution from a new source of
flavor-changing neutral current, which also violates CP invariance. The
CP-conjugate processes then may sizably differ in decay width. If a new
CP-violating phase is not suppressed, this decay rate asymmetry can be
significantly larger than the prediction by the standard model, possibly
detectable at B factories. Such a large asymmetry may be implied by the
measured branching ratio which is consistent with the standard model.


title:
Vacuum Solutions of Neutrino Anomalies Through a Softly Broken U(1)
  symmetry

abstract:
  We discuss an extended SU(2)XU(1) model which naturally leads to mass scales
and mixing angles relevant for understanding both the solar and atmospheric
neutrino anomalies in terms of the vacuum oscillations of the three known
neutrinos. The model uses a softly broken L_e-L_{\mu}-L_{\tau} symmetry and
contains a heavy scale M_H\sim 10^{15} GeV. The L_e-L_{\mu}-L_{\tau} symmetric
neutrino masses solve the atmospheric neutrino anomaly while breaking of
L_e-L_{\mu}-L_{\tau} generates highly suppressed radiative mass scale
\Delta_S\sim 10^{-10} eV^2 needed for the vacuum solution of the solar neutrino
problem. All the neutrino masses in the model are inversely related to M_H,
thus providing seesaw-type of masses without invoking any heavy right-handed
neutrinos. Possible embedding of the model into an SU(5) grand unified theory
is discussed.


title: Linking Parton Distributions to Form Factors and Compton Scattering

abstract:
  We relate ordinary and skewed parton distributions to soft overlap
contributions to elastic form factors and large angle Compton scattering, using
light-cone wave functions in a Fock state expansion of the nucleon. With a
simple ansatz for the wave functions of the three lowest Fock states we achieve
a good description of unpolarised and polarised parton distributions at large
x, and of the data for the Dirac form factor and for Compton scattering, both
of which can be saturated with soft contributions only. Large angle Compton
scattering appears as a good case to investigate the relative importance of
soft and hard contributions in exclusive processes which are sensitive to the
end point regions of the nucleon wave function.


title: Signal and Backgrounds for Leptoquarks at the LHC II: Vector Leptoquarks

abstract:
  We perform a detailed analyses of the CERN Large Hadron Collider (LHC)
capability to discover first generation vector leptoquarks through their pair
production. We study the leptoquark signals and backgrounds that give rise to
final states containing a pair e+e- and jets. Our results show that the LHC
will be able to discover vector leptoquarks with masses up to 1.3-2.1 TeV
depending on their couplings to fermions and gluons.


title: Double D-term inflation

abstract:
  Comparisons of cosmological models to current data show that the presence of
a non-trivial feature in the primordial power spectrum of fluctuations, around
the scale k=0.05 h/Mpc, is an open and exciting possibility, testable in a near
future. This could set new constraints on inflationary models. In particular,
current data favour a Lambda-CDM model with a steplike spectrum, and more power
on small scales. So far, this possibility has been implemented only in toy
models of inflation. In this work, we propose a supersymmetric model with two
U(1) gauge symmetries, associated with two Fayet-Iliopoulos terms. Partial
cancellation of the Fayet-Iliopoulos by one of the charged fields generates a
step in the primordial power spectrum of adiabatic perturbations. We show that
when this field if charged under both symmetries, the spectrum may have more
power on small scales.


title:
Process Z->h(A)+gamma in the Two Higgs Doublet Model and the
  Experimental Constraints from LEP

abstract:
  The one-loop branching ratios for the process Z->h(A)+gamma are calculated in
the general Two Higgs Doublet Model (Model II) taking into account existing
constraints on the model parameters. For Higgs boson masses below 50 GeV and
tan beta of order 1-10 the fraction of such Z decays are at the level of
10^{-7}, but can be significantly stronger for very low or high tan beta, where
the dependence of these results on other model parameters like sin(beta-alpha)
and the mass of the charged Higgs boson is found to be of little importance.
The results are compared to the LEP measurements, which are sensitive to
branching ratios of Z->h(A)+gamma of the order 10^{-5} for masses larger than
20 GeV, but approach 10^{-6} for low masses. Relating the expectation to the
experimental limits, constraints on the parameter space of the 2HDM are
derived.


title:
Electric Dipole Moments in Gauge Mediated Models and a Solution to the
  SUSY CP Problem

abstract:
  The SUSY CP problem in the framework of gauge mediated SUSY breaking model is
considered. We first discuss the electric dipole moments of the electron and
neutron, which are likely to be larger than the experimental upper bound if all
the phases in the Lagrangian are O(1). We derive a constraint on the phases in
the so-called $\mu$- and $B_\mu$-parameters and gaugino masses. Then, we
discuss a model in which the CP violating phase can be adequately suppressed.
If the $\mu$- and $B_\mu$-parameters originate from the same superpotential
interaction as the SUSY breaking field, the CP violating phase vanishes.
However, in this class of models, the ratio $B_\mu/\mu$ becomes too large, and
we discuss a possible scenario to fix this problem.


title: On A New Class of Models for Soft CP Violation

abstract:
  We elaborate on a new class of models proposed recently by us and compare
with another class proposed by Georgi and Glashow(GG). The models can be
roughly classified as the righted-handed (or left-handed) models in our (or
GG's) case. Both classes of models use softly broken CP symmetry to suppress
tree level KM phase as well as the strong CP phase. The measured value of the
CP-violating parameter $\epsilon$ are accounted for by employing a new heavy
sector of scalars and vectorial fermions. The models can be milliweak or
superweak in nature depending on the scale of the heavy sector. We review the
phenomenology of the right-handed models and compare with the left-handed
models.


title: Semileptonic B -> rho and B -> a_1 transitions in a quark-meson model

abstract:
  We evaluate the form factors governing the exclusive decays B->rho l nu,
B->a_1 l nu, by using an effective quark-meson lagrangian. The model is based
on meson-quark interactions, and the computation of the mesonic transition
amplitudes is performed by considering diagrams with heavy mesons attached to
loops containing heavy and light constituent quarks. This approach was
successfully employed to compute the Isgur-Wise form factors and other hadronic
observables for negative and positive parity heavy mesons and is presently used
for exclusive heavy-to-light weak transitions. We also evaluate a few strong
coupling constants appearing in chiral effective lagrangians for heavy and
light mesons.


title: The Parton Content of Virtual Photons

abstract:
  The QCD treatment of the parton structure of virtual photons is briefly
recalled, and possible limitations and open questions are pointed out. Various
models for these densities are compared, completed by a short discussion of the
treatment of heavy flavors. Finally, different ways to measure the parton
distributions of virtual photons in e^+e^- and ep experiments are summed up.


title: Chiral sum rules and duality in QCD

abstract:
  The ALEPH data on the vector and axial-vector spectral functions, extracted
from tau-lepton decays is used in order to test local and global duality, as
well as a set of four QCD chiral sum rules. These are the Das-Mathur-Okubo sum
rule, the first and second Weinberg sum rules, and a relation for the
electromagnetic pion mass difference. We find these sum rules to be poorly
saturated, even when the upper limit in the dispersion integrals is as high as
$3 GeV^{2}$. Since perturbative QCD, plus condensates, is expected to be valid
for $|q^{2}| \geq \cal{O}$$(1 GeV^{2})$ in the whole complex energy plane,
except in the vicinity of the right hand cut, we propose a modified set of sum
rules with weight factors that vanish at the end of the integration range on
the real axis. These sum rules are found to be precociously saturated by the
data to a remarkable extent. As a byproduct, we extract for the low energy
renormalization constant $\bar{L}_{10}$ the value $- 4 \bar{L}_{10}= 2.43
\times 10^{-2}$, to be compared with the standard value $- 4 \bar{L}_{10} =
(2.73 \pm 0.12) \times 10^{-2}$. This in turn implies a pion polarizability
$\alpha_{E} = 3.7 \times 10^{-4} fm^{3}$.


title: Sudakov Form Factors with an Effective Theory of Particle Worldlines

abstract:
  Sudakov-type form factors for quark vertex functions in QCD are discussed
using a worldline approach.


title: Strange Quark Mass Dependence of the Tau Hadronic Width

abstract:
  The perturbative quark mass corrections to the tau hadronic width are studied
to O(alpha_s^3 m_q^2). Including up to dimension four corrections, we get m_s(4
GeV^2)=(143 \pm 42) MeV [m_s(1 GeV^2)=(193 \pm 59) MeV ]. Possible improvements
to reduce the theoretical uncertainty are pointed out.


title: A Modern Introduction to Quarkonium Theory

abstract:
  Recent advances in lattice and continuum QCD have given us new insights into
quarkonium physics. These set of lectures are intend for the uninitiated. We
first give a physical picture of quarkonium and describe the hybrids states
established in lattice QCD. Then we give an unorthodox presentation of
Non-Relativistic QCD (NRQCD) including a novel method for the application of
spin-symmetries. Finally we describe the prototypical application of NRQCD:
cancellation of infrared divergences in decays of P-wave quarkonia.


title: Neutrino masses and mixings from an SMG \times U(1)^2 model

abstract:
  A natural solution to the fermion mass hierarchy problem suggests the
existence of a partially conserved chiral symmetry. We show that this can lead
to a reasonably natural solution to the solar and atmospheric neutrino problems
without fine-tuning or the addition of new low energy fermions. The atmospheric
neutrino atmospheric neutrino anomaly is given by large mixing between
$\nu_{\mu}$ and $\nu_{\tau}$, with $\Delta m^2_{atm} \sim 10^{-3} \eV^2$, and
the solar neutrino deficit is due to nearly maximal electron neutrino vacuum
oscillations. We present an explicit model for the neutrino masses which is an
anomaly free Abelian extension of the standard model that also yields a
realistic charged fermion spectrum.


title: Minimal See-Saw Model for Atmospheric and Solar Neutrino Oscillations

abstract:
  We present a minimal see-saw model based on an extension of the standard
model (SM) which includes an additional U(1), with gauge charge $B -
\frac{3}{2} (L_\mu + L_\tau)$. Requirement of anomaly cancellation implies the
existence of two right-handed singlet neutrinos, carrying this gauge charge,
which have normal Dirac couplings to $\nu_\mu$ and $\nu_\tau$ but suppressed
ones to $\nu_e$. Assuming the U(1) symmetry breaking scale to be
10$^{12-16}$~GeV, this model can naturally account for the large (small) mixing
solutions to the atmospheric (solar) neutrino oscillations.


title: On the physics of massive neutrinos

abstract:
  Massive neutrinos open up the possibility for a variety of new physical
phenomena. Among them are oscillations and double beta decay. Furthermore they
influence several fields from particle physics to cosmology. In this article
the concept of massive neutrinos is given and the current status of
experimental research is extensively reviewed. This includes astrophysical
studies of solar, supernova and very high energy neutrinos. Future perspectives
are also outlined.


title: Tau neutrino fluxes from atmospheric charm

abstract:
  We present an evaluation of the atmospheric tau neutrino flux in the energy
range between $10^2$ and $10^6$ GeV. The main source of tau neutrinos is from
charmed particle production and decay. The $\nu_\tau N\to \tau X$ event rate
for a detector with a water equivalent volume of 1 km$^3$ is on the order of
60-100 events per year for $E_\tau>100$ GeV, reducing to 18 events above 1 TeV.
Event rates for atmospheric muon neutrino oscillations to tau neutrinos are
also evaluated.


title:
How does the geodesic rule really work for global symmetry breaking
  first order phase transitions?

abstract:
  The chain of events usually understood to lead to the formation of
topological defects during phase transitions is known as the Kibble mechanism.
A central component of the mechanism is the so-called ``geodesic rule''.
Although in the Abelian Higgs model the validity of the geodesic rule has been
questioned recently, it is known to be valid on energetic grounds for a global
U(1) symmetry breaking transition. However, even for these globally symmetric
models no dynamical analisys of the rule has been carried to this date, and
some points as to how events proceed still remain obscure. This paper tries to
clarify the dynamics of the geodesic rule in the context of a global U(1)
model. With an appropriate ansatz for the field modulus we find a family of
analytical expressions, phase walls, that accounts for both geodesic and
nongeodesic configurations. We then show how the latter ones are unstable and
decay into the former by nucleating pairs of defects. Finnally, we try to give
a physical perspective of how the geodesic rule might really work in these
transitions.


title:
Bose-Einstein Correlations in a Space-Time Approach to e+ e-
  Annihilation into Hadrons

abstract:
  A new treatment of Bose-Einstein correlations is incorporated in a space-time
parton-shower model for e+ e- annihilation into hadrons. Two alternative
afterburners are discussed, and we use a simple calculable model to demonstrate
that they reproduce successfully the size of the hadron emission region. One of
the afterburners is used to calculate two-pion correlations in e+ e- -> Z^0 ->
hadrons and e+ e- -> W+ W- -> hadrons. Results are shown with and without
resonance decays, for correlations along and transverse to the thrust jet axis
in these two classes of events.


title: Leptoquark Pair Production Cross Sections at Hadron Colliders

abstract:
  A compilation is given of the pair production cross sections for scalar and
vector leptoquarks in the kinematic range of the hadron colliders Tevatron and
LHC.


title: Wilsonian flow equation and thermal field theory

abstract:
  We review the use of Wilsonian renormalization group methods for quantum
field theories at finite temperature. The implementations within both real and
imaginary time formalism is carefully discussed. In particular, the question of
gauge invariance is addressed in detail. A recently proposed real time thermal
renormalization group is then used to derive the RG flows for Abelian Higgs
models. Further applications are outlined.


title:
Non-Equilibrium Bose-Einstein Condensates, Dynamical Scaling and
  Symmetric Evolution in large N Phi^4 theory

abstract:
  We analyze the non-equilibrium dynamics of the O(N) Phi^4 model in the large
N limit and for states of large energy density. The dynamics is dramatically
different when the energy density is above the top of the tree level potential
V_0 than when it is below it.When the energy density is below V_0, we find that
non-perturbative particle production through spinodal instabilities provides a
dynamical mechanism for the Maxwell construction. The asymptotic values of the
order parameter only depend on the initial energy density and all values
between the minima of the tree level potential are available, the asymptotic
dynamical `effective potential' is flat between the minima. When the energy
density is larger than V_0, the evolution samples ergodically the broken
symmetry states, as a consequence of non-perturbative particle production via
parametric amplification. Furthermore, we examine the quantum dynamics of phase
ordering into the broken symmetry phase and find novel scaling behavior of the
correlation function. There is a crossover in the dynamical correlation length
at a time scale t_s \sim \ln(1/lambda). For t < t_s the dynamical correlation
length \xi(t) \propto \sqrt{t} and the evolution is dominated by spinodal
instabilities, whereas for t>t_s the evolution is non-linear and dominated by
the onset of non-equilibrium Bose-Einstein condensation of long-wavelength
Goldstone bosons.In this regime a true scaling solution emerges with a non-
perturbative anomalous scaling length dimension z=1/2 and a dynamical
correlation length \xi(t) \propto (t-t_s). The equal time correlation function
in this scaling regime vanishes for r>2(t-t_s) by causality. For t > t_s the
equal time correlation function falls of as 1/r. A semiclassical but stochastic
description emerges for time scales t > t_s.


title: Nonspectator Effects and B Meson Lifetimes

abstract:
  We review the B meson lifetime problems and nonspectator effects. The
predictions of B meson lifetime ratios depend on four unknown hadronic
parameters $B_1$, $B_2$, $\epsilon_1$ and $\epsilon_2$, where $B_1$ and $B_2$
parametrize the matrix elements of color singlet-singlet four-quark operators
and $\epsilon_1$ and $\epsilon_2$ the matrix elements of color octet-octet
operators. To understand contributions of the nonspectator effects to the B
meson lifetime ratios, we derive the renormalization-group improved QCD sum
rules for these parameters within the framework of heavy quark effective
theory.


title: Short-distance tachyonic gluon mass and 1/Q^2 corrections

abstract:
  We consider the assumption that a tachyonic gluon mass imitates
short-distance nonperturbative physics of QCD. The phenomenological
implications include modifications of the QCD sum rules for correlators of
currents with various quantum numbers. The new 1/Q^2 terms allow to resolve in
a natural way old puzzles in the pion and scalar-gluonium channels. They lead
to a slight reduction of the values of the running light quark masses from the
(pseudo)scalar sum rules and of alpha_s(M_\tau) from tau decay data. Further
tests can be provided by precision measurements of the correlators on the
lattice and by the e^+e^- --> hadrons data.


title: Glueballs : the Naked Truth

abstract:
  The current status of the accepted glueball candidates is reviewed. The
difference between bare and dressed hadrons is emphasised. What two photon
processes, both production and decay, have taught us about these is discussed.


title: Strange Magnetism

abstract:
  We present an analytic and parameter-free expression for the momentum
dependence of the strange magnetic form factor of the nucleon and its
corresponding radius which has been derived in Heavy Baryon Chiral Perturbation
Theory. We also discuss a model-independent relation between the isoscalar
magnetic and the strange magnetic form factors of the nucleon based on chiral
symmetry and SU(3) only. These limites are used to derive bounds on the strange
magnetic moment of the proton from the recent measurement by the SAMPLE
collaboration.


title: Effects of Parton kt in High-pt Particle Production

abstract:
  We report on recent work concerning the phenomenology of initial-state
parton-kt effects in direct-photon production and related processes in hadron
collisions. After a brief summary of a kt-smearing model, we present a study of
recent results on fixed-target and collider direct-photon production, using
complementary data on diphoton and pion production that provide empirical
guidance on the required amount of kt broadening. This approach provides a
consistent description of the observed deviations of next-to-leading order QCD
calculations relative to the inclusive direct-photon and pizero data. We also
comment on the implications of these results for the extraction of the gluon
distribution of the nucleon.


title: Non-perturbative QCD spin studies

abstract:
  A whole class of non-perturbative QCD studies, e.g. the instanton models,
chiral quark models, etc. indicates that the effective degrees of freedom for
the physics in the low Q^(2) < 1 GeV^(2) region could be the constituent quarks
(CQs) and internal Goldstone bosons (IGBs). This leads to a nucleon structure
with the spin being carried by three constituent quark systems, each composed
of a massive compact CQ surrounded by a q\bar{q} sea perturbatively generated
by the valence quark's IGB emissions. Such a CQ-system has a total angular
momentum of 1/2 and a small anomalous magnetic moment, built up from a
quark-spin polarization and a significant orbital motion in the quark sea. The
distinctive phenomenological signal for such a non-perturbative structure is
that the sea-quarks are polarized negatively, while the antiquarks are not
polarized. This picture also suggests a negligibly small gluon polarization.
All such features can be tested by experiments in the near future.


title: Soft superweak CP violation in a 331 model

abstract:
  We show that it is possible to implement soft superweak CP violation in the
context of a 331 model with only three triplets. All CP violation effects come
from the exchange of singly and doubly charged scalars. We consider the
implication of this mechanism in the quark and lepton sectors. In particular it
is shown that in this model, as in most of those which incorporate the scalar
mediated CP violation, it is possible to have large electric dipole moments for
the muon and the tau lepton while keeping small those of the electron and the
neutron. The CKM mixing matrix is real up to the two loop level.


title: Spin Issues in t-tbar Production and Decay

abstract:
  We describe the off-diagonal spin basis for observing angular correlations in
top quark pair production events at the Fermilab Tevatron. For events initiated
by quark-antiquark annihilation, the top and antitop quark spins are 100%
correlated in this basis: a spin-up top quark is always accompanied by a
spin-down antitop quark and vice versa. Inclusion of the gluon-gluon initial
state lowers the fraction of unlike spin events to 92%. Nevertheless, the
angular correlations between the top and antitop quark decay products are twice
as large in the off-diagonal basis as those in the more traditional helicity
basis. We give two brief examples of how the presence of new physics would
alter these correlations.


title:
Neutrino Oscillations and Other Key Issues in Supersymmetric SU(4)_c
  \times SU(2)_L \times$ SU(2)_R

abstract:
  We try to gain an understanding of the recent Superkamiokande data on
neutrino oscillations and several other important phenomenological issues
within the framework of supersymmetric $SU(4)_c \times SU(2)_L \times SU(2)_R$
($\equiv G_{422}$). By supplementing $G_{422}$ with a U(1)-${\cal R}$ symmetry,
we can provide an explanation of the magnitude $M_G$ ($\sim 10^{16}$ GeV) of
the $G_{422}$- symmetry breaking scale, resolve the MSSM $\mu $ problem, and
understand why proton decay has not been seen ($\tau_p \gg 10^{34}$ yr). The
family dependent ${\cal R}$ - symmetry also helps provide an explanation of the
charged fermion mass hierarchies as well as the magnitudes of the CKM matrix
elements. Several additional heavy states in the mass range $10^4-10^7$ GeV are
predicted, and the MSSM parameter $\tan \beta $ turns out to be of order unity.
The atmospheric neutrino problem is explained through $\nu_{\mu}-\nu_{\tau}$
mixing with $\sin^2 2\theta_{\mu \tau}\simeq 1$. The resolution of the solar
neutrino puzzle is via the small angle MSW oscillations and necessarily
requires a sterile neutrino $\nu_s$ which, thanks to the ${\cal R}$ - symmetry,
has a tiny mass.


title: On Bose-condensation of wave-packets in heavy ion collisions

abstract:
  A recently obtained exact analytic solution to the wave-packet version of the
pion-laser model is presented. In the rare gas limit, a thermal behaviour is
found while the dense gas limiting case corresponds to Bose-Einstein
condensation of wave-packets to the wave-packet mode with the smallest possible
energy.


title: Cosmological Fine Tuning, Supersymmetry, and the Gauge Heirarchy Problem

abstract:
  We study the extent to which the cosmological fine-tuning problem - why the
relic density of neutralino cold dark matter particles $\chi$ is similar to
that of baryons - is related to the fine-tuning aspect of the gauge hierarchy
problem - how one arranges that M_W << M_P without unnatural choices of MSSM
parameters. Working in the minimal supergravity framework with universal soft
supersymmetry-breaking parameters as inputs, we find that the hierarchical fine
tuning is minimized for \Omega_{\chi} h^2 \sim 0.1. Conversely, imposing
\Omega_{\chi} h^2 < 1 does not require small hierarchical fine tuning, but the
exceptions to this rule are rather special, with parameters chosen such that
m_{\chi}\sim M_Z/2 or M_h/2, or else m_{\chi} \simgt m_t. In the first two
cases, neutralino annihilation receives a large contribution from a
direct-channel pole, whereas in the third case it is enhanced by the large top
Yukawa coupling.


title:
Quark initiated coherent diffractive production of muon pair and W boson
  at hadron colliders

abstract:
  The large transverse momentum muon pair and W boson productions in the quark
initiated coherent diffractive processes at hadron colliders are discussed
under the framework of the two-gluon exchange parametrization of the Pomeron
model. In this approach, the production cross sections are related to the
small-x off-diagonal gluon distribution and the large-x quark distribution in
the proton (antiproton). By approximating the off-diagonal gluon distribution
by the usual gluon distribution function, we estimate the production rates of
these processes at the Fermilab Tevatron.


title:
Renormalization group and relations between scattering amplitudes in a
  theory with different mass scales

abstract:
  In the Yukawa model with two different mass scales the renormalization group
equation is used to obtain relations between scattering amplitudes at low
energies. Considering fermion-fermion scattering as an example, a basic
one-loop renormalization group relation is derived which gives possibility to
reduce the problem to the scattering of light particles on the "external field"
substituting a heavy virtual state. Applications of the results to problems of
searching new physics beyond the Standard Model are discussed.


title:
Phenomenon of the time-reversal-violating photon polarization plane
  rotation by a gas placed to an electric field

abstract:
  T-odd P-odd phenomenon of the photon polarization plane rotation (circular
dichroism) is considered for an atomic (molecules) gas placed to an electric
field. The expression for the T non-invariant polarizability of an atom
(molecule) placed to an electric field is obtained. It is shown that the T-odd
plane rotation angle increases when the interaction energy of an atom
(molecule) with an electric field is the same order as the opposite parity
levels spacing.


title: Resonant production of fermions in an axial background

abstract:
  We consider the resonant production of fermions from an oscillating axial
background. The classical evolution of the axial field is given by that of a
massive pseudovector field, as suggested by the renormalizability of the
theory. We look upon both the massive and the massless fermion production from
a perturbative point of view. We obtain the corresponding spectrum and angular
distributions for the different spins or helicities in the particular case of a
spatial-like axial field. We also extend our study to the non-perturbative
regime in the massless case and compare the results with the perturbative ones.


title: Sphalerons with CP-Violating Higgs Potentials

abstract:
  We investigate the effect on the sphaleron in the two Higgs doublet
electroweak theory of including CP violation in the Higgs potential. To have
better control over the relation between the sphaleron energy and the physical
quantities in the theory, we show how to parametrize the Higgs potential in
terms of physical masses and mixing angles, one of which causes CP violation.
By altering this CP violating angle (and keeping the other physical quantities
fixed) the sphaleron energy increases by up to 10%. We also calculate the
static minimum energy path between adjacent vacua as a function of Chern-Simons
number, using the method of gradient flow. The only effect CP violation has on
the barrier is the change in height. As a by-product of our work on
parametrization of the potential, we demonstrate that CP violation in the Higgs
sector favours nearly degenerate light Higgs masses.


title: QCD-bag mass spectrum and phase transitions

abstract:
  We obtain the hadronic mass spectrum in the `bag of bags' statistical
bootstrap model (BBSBM), implementing the colorless state condition, aside of
baryon and strangeness conservation, using group projection method. We study
the partition function, investigate the properties of dense hadronic matter,
and determine the conditions under which the system undergoes a phase
transition to a deconfined quark-gluon plasma. We show that a phase transition
cannot occur in the N=1 (Abelian) limit of our model, and is first order for
QCD-like case N=3.


title: Quantum Gravity and Extra Dimensions at High-Energy Colliders

abstract:
  Recently it has been pointed out that the characteristic quantum-gravity
scale could be as low as the weak scale in theories with gravity propagating in
higher dimensions. The observed smallness of Newton's constant is a consequence
of the large compactified volume of the extra dimensions. We investigate the
consequences of this supposition for high-energy collider experiments. We do
this by first compactifying the higher dimensional theory and constructing a
3+1-dimensional low-energy effective field theory of the graviton Kaluza-Klein
excitations and their interactions with ordinary matter. We then consider
graviton production processes, and select photon plus missing energy and jet
plus missing energy signatures for careful study. We find that both a 1 TeV
e+e- collider and the CERN LHC will be able to reliably and perturbatively
probe the fundamental gravity scale up to several TeV, with the precise value
depending on the number of extra dimensions. Similarly, searches at LEP2 and
the Tevatron are able to probe this scale up to approximately 1 TeV. We also
discuss virtual graviton exchange, which induces local dimension-eight
operators associated with the square of the energy-momentum tensor. We estimate
the size of such operators and study their effects on two fermions to two
photons observables.


title:
Double Scattering Effect in Transverse Momentum Distribution of
  Inclusive $J/\psi$ Production in Photo-Nucleus Collision

abstract:
  In terms of multiple scattering picture, we calculate the double scattering
effect in the transverse momentum distribution of $J/\psi$ photoproduction.
Applying the generalized factorization theorem, we find that the contributions
from double scattering can be expressed in terms of twist-4 nuclear parton
correlation functions, which is the same as that used to explain the nuclear
dependence in di-jet momentum imbalance and in direct photon production. Using
the known information on the twist-4 parton correlation functions, we estimate
that the double scattering contributes a small suppression in $J/\psi$
photoproduction. In the analysis we only take into account the leading order in
the small velocity expansion for the nonperturbative parts related to the
quarkonium.


title: The operator-product expansion away from euclidean region

abstract:
  The role of the operator-product expansion in QCD calculations is discussed.
Approximating the two-point correlation function by several terms and assuming
an upper bound on the truncation error along the euclidean ray, we consider two
model situations to examine how the bound develops with increasing deflection
from the euclidean ray towards the cut. We obtain explicit bounds on the
truncation error and show how they worsen with the increasing deflection. The
result does not support the believe that the remainder is constant for all
angles in the complex energy plane. Further refinements of the formalism are
dicussed.


title: QCD '98: status of the power corrections

abstract:
  We review status of the power corrections in QCD. The topics include shape
variables, unconventional 1/Q^2 corrections, tachyonic gluon mass as a fit
parameter to the 1/Q^2 corrections. The selection of the material is determined
mostly by results presented at the Conference QCD'98 (Montpellier, July 1998).
Some background comments are also included.


title:
The Interaction Structure and Cosmological Relevance of Mass Scales in
  String Motivated Supersymmetric Theories

abstract:
  A string motivated, N=1 global supersymmetric, general Lagrangian is obtained
that represents an inflaton interacting with the modes of a string. Focus is
placed on the Lagrangian's relevance to warm inflation, which is a cosmology
based on dissipative dynamics. Several interaction schemes are identified from
the general Lagrangian that may have interesting consequences for dissipative
dynamics. Distributed-mass-models, which have been shown to solve the horizon
problem within a warm inflation regime, are identified in the general
Lagrangian.


title: Neutrino Conversion and Neutrino Astrophysics

abstract:
  We consider main ingredients which determine neutrino transformations in
media. Strong transformations relevant for the astrophysics can be due to large
depth oscillations, resonance conversion, parametric resonance effect,
interplay of oscillations and inelastic collisions. Properties of transitions
are discussed using the graphic representation. The applications of the
transitions to supernova neutrinos are described. The supernova neutrinos can
probe whole neutrino mass spectrum. Their studies will help to identify the
pattern of neutrino mass and mixing.


title:
Neutrino Oscillations: a source of Goldstone fields and consequences for
  Supernovae

abstract:
  It is shown that true Nambu-Goldstone (NG) bosons develop coherent fields
whenever the associated charges of the matter particles are not conserved in a
macroscopic scale. The sources of the NG fields are the time rates of quantum
number violation. If the lepton numbers are spontaneously broken at a scale
below 1 TeV, the neutrino oscillation processes generate classic NG fields that
are strong enough in Supernovae to modify the neutrino flavor dynamics. The
oscillation patterns may change in the periods of largest $\nu $ fluxes. Two
examples are given: 1. the back reaction of a NG field improves the
adiabaticity of the $\nu_{e}$ resonant conversion; 2. ${\bar{\nu}_{e}}
\leftrightarrow {\bar{\nu}_{\mu}}$ oscillations may occur even if $\nu_{e}$ is
the lightest of the neutrinos.


title:
High Temperature Symmetry Breaking, SUSY Flat Directions, and the
  Monopole Problem

abstract:
  Supersymmetric flat directions allow a generic counterexample to the
phenomenon of symmetry restoration at high temperatures. We show that
(exponentially) large VEVs can be developed along these directions through
temperature-induced `dimensional transmutation'. A minimum with broken gauge
charges (e.g. electric charge) can exist at arbitrarily high temperatures. In
such a scenario magnetic monopoles are never formed, independent of whether
inflation occurs before or after the GUT phase transition, or whether it occurs
at all.


title: U(2) and Maximal Mixing of nu_{mu}

abstract:
  A U(2) flavor symmetry can successfully describe the charged fermion masses
and mixings, and supress SUSY FCNC processes, making it a viable candidate for
a theory of flavor. We show that a direct application of this U(2) flavor
symmetry automatically predicts a mixing of 45 degrees for nu_mu to nu_s, where
nu_s is a light, right-handed state. The introduction of an additional flavor
symmetry acting on the right-handed neutrinos makes the model
phenomenologically viable, explaining the solar neutrino deficit as well as the
atmospheric neutrino anomaly, while giving a potential hot dark matter
candidate and retaining the theory's predictivity in the quark sector.


title: Trilepton Signal of Grand Unified Models at the Tevatron

abstract:
  At the Tevatron, the most promising channel to detect supersymmetry is three
leptons plus missing energy, where the leptons are $e$'s and/or $\mu$'s. This
final state appears from the production of chargino and second lighetst
neutralino. However in grand unified models with universal scalar masses at the
grand unified scale, this final state mostly consists of $\tau$'s which are
hard to detect. We show that for some regions of non universality in the scalar
masses at the GUT scale based on unifying groups like SU(5) or SO(10), the
final state mostly consists of 3$l$+${\rlap/E}_T$ and $\tau ll$+${\rlap/E}_T$.
The first mode has very high detection efficiency and the second one is
expected to have high detection efficency as well. We also show that these
models can have enough events in these modes to be detected in RUN II.


title: Quantum Kinetic Equation and Cosmic Pair Annihilation

abstract:
  Pair annihilation of heavy stable particle that occurs in the early universe
is investigated, and quantum kinetic equation for the momentum distribution of
the annihilating particle is derived, using the influence functional method. A
bosonic field theory model is used to describe the pair annihilation in the
presence of decay product particles making up a thermal environment. A crossing
symmetric Hartree approximation that determines self-consistently the
equilibrium distribution is developed for an otherwise intractable theory. The
time evolution equation and its Markovian approximation is derived, to give a
generalized Boltzmann equation including off-shell effects. The narrow width
approximation to an energy integral in this equation gives the usual Boltzmann
equation in a thermal bath of light particles. The off-shell effect is a
correction to the Boltzmann equation at high temperatures, but is dominant at
low temperatures. The effect changes the equilibrium distribution from the
familiar $1/(e^{\omega_{k}/T} - 1)$ to a modified one given by a Gibbs formula.
Integrated over momenta, the particle number density becomes roughly of order
(coupling) $\times \sqrt{T/M}\cdot T^{3}$ at low temperatures for the S-wave
annihilation. The relic mass density in the present universe is insensitive to
the coupling strength in a large range of the mass and the coupling parameters,
and scales with the WIMP mass as (\approx 6 \times 10^{4} eV cm^{-3}
(M/GeV)^{4/3}). The bound from the closure density gives an upper WIMP mass
bound roughly of order 1 $GeV$ in the present model.


title: Quantum theory of transition radiation and transition pair creation

abstract:
  Theory of the transition radiation and the transition pair creation is
developed in the frame of QED. The spectral-angular distributions of
probability of the transition radiation and of the transition pair creation are
found. The total energy losses of and the total probability of pair creation
are calculated and analyzed. Features of radiation and pair creation processes
in a superdence medium (typical for white dwarfs) are discussed.


title:
Exclusive Rare Decays of Heavy Baryons to Light Baryons: $\Lambda_b \ri
  ghtarrow \Lambda \gamma$ and $\Lambda_b \to \Lambda l^{+} l^{-}$

abstract:
  Rare decays $\Lambda_b \to \Lambda \gamma$ and $\Lambda_b \to \Lambda l^{+}
l^{-}$ (l= e, $\mu$) are examined. We use QCD sum rules to calculate the
hadronic matrix elements governing the decays. The $\Lambda$ polarization in
the decays is analyzed and it is shown that the polarization parameter in
$\Lambda_b \to \Lambda \gamma$ does not depends on the values of hadronic form
factors. And the energy spectrum of $\Lambda$ in $\Lambda_b \to \Lambda l^{+}
l^{-}$ is given.


title: Neutrino Mass and an Ever Expanding Universe (an Irreverent Perspective)

abstract:
  There have been two significant recent findings. One is a culmination of the
Superkamiokande experiments, which demonstrate Neutrino oscillation and
therefore a non-zero mass. The other is the finding that the universe will
continue to expand without declaration based on distant supernovae
observations. At the very least these two findings call for a review of the
existing and generally accepted theories. In this talk it is pointed out how
such a Neutrino Mass can in fact be deduced from a theoretical model, as also
the eternal expansion feature of the universe, and how both these findings do
not contradict each other.


title:
Upon symmetry of baryon magnetic moments in the chiral and the
  quark-soliton models

abstract:
  It is shown that the baryon magnetic moment descriptions in the frameworks of
the chiral model ChPT and the quark soliton $\chi QSM $ one are practically
identical. The main difference from the traditional unitary symmetry models
proves to be in terms due to the pionic current contribution into the magnetic
moments of nucleons and in the prediction for the $\Lambda$ magnetic moment.


title: Elastic cross sections for high energy hadron-hadron scattering

abstract:
  This report discusses some results on differential cross sections for high
energy and small momentum transfer elastic hadron-hadron scattering in QCD,
using a functional integral approach. In particulary a matrix cumulant
expansion for the vacuum expectation values of lightlike Wegner-Wilson loops,
which governs the hadronic amplitudes, is presented. The cumulants are
evaluated using the model of the stochastic vacuum.


title: Non-Equilibrium Phase Transition in Rapidly Expanding Matter

abstract:
  Non-equilibrium features of a first order phase transition from the
quark-gluon plasma to a hadronic gas in relativistic heavy-ion collisions are
discussed. It is demonstrated that strong collective expansion may lead to the
fragmentation of the plasma phase into droplets surrounded by undersaturated
hadronic gas. Subsequent hadronization of droplets will generate strong
non-statistical fluctuations in the hadron rapidity distribution in individual
events. The strongest fluctuations are expected in the vicinity of the phase
transition threshold.


title: Signatures of Supersymmetry and Yukawa Unification in Higgs Decays

abstract:
  We show that the branching ratio R_{b/tau}=BR(h^0->bb)/BR(h^0->tau tau) of
the Higgs boson h^0 may usefully differentiate between the Higgs sectors of the
Minimal Supersymmetric Standard Model (MSSM) and non-supersymmetric models such
as the Standard Model or its two Higgs doublet extensions. Although at tree
level R_{b/tau} is the same in all these models, only in the MSSM can it
receive a large radiative correction, for moderate to large values of the
parameter tan(beta). Such large corrections are motivated in supersymmetric
unified schemes wherein the Yukawa couplings of the b-quark and the tau-lepton
are equal at the unification scale; otherwise the b-quark mass prediction is
too large by 15-30% for most of parameter space. Thus accurate measurements of
the Higgs branching ratios can probe physics at the unification scale. The
branching ratio of h^0 into charm quarks, as well as of the other Higgs bosons
(H^0,A^0) into bb, tau tau, and cc can provide additional information about the
supersymmetric nature of the Higgs sector.


title: Summary and Outlook

abstract:
  This summary is organized into four parts. In the first section (News) I
discuss the SuperKamiokande results on atmospheric neutrino oscillations, as
well as recent results from cosmology. The second section (Refinements) focuses
on electroweak tests, recent results in the flavor sector and in probing QCD,
as well as searches for new particles. The third section (Mysteries) discusses
issues associated with neutrino masses and mixings in more depth. Finally, in
the last section (Hopes) I reflect on both the short and long term future of
the field.


title: "Non-Perturbative Methods" in Field Theory

abstract:
  This talk is an overview of selected topics related to renormalization group
flows and the phases of gauge theories.


title: Evolution of Axionic Strings and Spectrum of Axions Radiated from Them

abstract:
  Cosmological evolution of axionic strings is investigated by numerically
solving field equations of a complex scalar field in 3+1 dimensions. It is
shown that the global strings relax to the scaling solution with a
significantly smaller number density than the case of local strings. The power
spectrum of axions radiated from them is calculated from the simulation data,
which is found to be highly peaked around the Hubble scale, and a more accurate
constraint on the Peccei-Quinn breaking scale is obtained.


title:
Model-independent analysis of soft masses in heterotic string models
  with anomalous U(1) symmetry

abstract:
  We study the magnitudes of soft masses in heterotic string models with
anomalous U(1) symmetry model-independently. In most cases, D-term contribution
to soft scalar masses is expected to be comparable to or dominant over other
contributions provided that supersymmetry breaking is mediated by the
gravitational interaction and/or an anomalous U(1) symmetry and the magnitude
of vacuum energy is not more than of order $m_{3/2}^2 M^2$.


title: Standard Model Theory

abstract:
  In this conference report a summary is given on the theoretical work that has
contributed to provide accurate theoretical predictions for testing the
standard model in present and future experiments. Precision calculations for
the vector boson masses, for the Z resonance, W pair production, and for the
g-2 of the muon are reviewed and the theoretical situation for the Higgs sector
is summarized. The status of the standard model is discussed in the light of
the recent high and low energy data. New Physics beyond the standard model is
briefly addressed as well, with special emphasis on the minimal supersymmetric
standard model. A few references have been added.


title: Primary Cosmic-ray Spectrum and the Intensity of Atmospheric Neutrinos

abstract:
  Measurements of the intensity of primary cosmic-ray protons reported in the
last two years suggest a lower normalization than some earlier measurements.
Here we comment on the measurements, compare them to assumptions made in two
independent calculations of atmospheric neutrinos and discuss the possible
consequences for interpretation of measurements of atmospheric neutrinos.


title: Fluxes of Atmospheric Neutrinos and Related Cosmic Rays

abstract:
  The atmospheric neutrino beam simultaneously spans a range of pathlengths
from ten to ten thousand kilometers, which correspond respectively to downward-
and upward-going neutrinos. As with any neutrino oscillation experiment, also
in this case the interpretation of the data depends on a detailed knowledge of
the neutrino beam. The ingredients are the primary spectrum of cosmic-ray
nucleons, the geomagnetic fields in which the charged particles propagate and
the properties of interactions of hadrons in the atmosphere. In this talk I
review the status of calculations in light of the recent evidence for neutrino
oscillations from Super-Kamiokande (Y. Fukuda et al., Phys. Rev. Letters 81
(1998) 1562).


title: Generic and Chiral Extensions of the Supersymmetric Standard Model

abstract:
  We construct extensions of the Standard Model in which the gauge symmetries
and supersymmetry prevent the dangerously large effects that may potentially be
induced in a supersymmetric standard model by Planck scale physics. These
include baryon number violation, flavor changing neutral currents, the $\mu$
term, and masses for singlet or vector-like fields under the Standard Model
gauge group. For this purpose we introduce an extra non-anomalous $U(1)_\mu$
gauge group. Dynamical supersymmetry breaking in a secluded sector triggers the
breaking of the $U(1)_\mu$ and generates soft masses for the superpartners via
gauge mediation, with the scalars possibly receiving sizable contributions from
the $U(1)_\mu$ D-term. We find several classes of complete and calculable
models, in which the messengers do not present cosmological problems and
neutrino masses can also be accomodated. We derive the sparticle spectrum in
these models and study the phenomenological consequences. We give an exhaustive
list of the potential experimental signatures and discuss their observability
in the upcoming Tevatron runs. One class of models exhibits interesting new
discovery channels, namely $WW \not E_T$, $W\gamma \not E_T$ and $WZ \not E_T$,
which arise when the next-to-lightest supersymmetric particle is a short-lived
$SU(2)_W$ neutralino.


title:
Light-front Hamiltonian field theory. Towards a relativistic description
  of bound states

abstract:
  My thesis contains an introduction to Light-front Hamiltonian field theory
and updates of published articles: - "Equivalence of Covariant and Light-Front
Perturbation Theory" (hep-ph/9702311 and hep-ph/9806365, N. C. J.
Schoonderwoerd and B. L. G. Bakker, published in Phys.Rev.D) and -
"Entanglement of Fock-space expansion and covariance in light-front Hamiltonian
field theory" (hep-ph/9806365, N. C. J. Schoonderwoerd, B. L. G. Bakker and
V.A. Karmanov, accepted for publication in Phys.Rev.C.)


title:
On a possible estimation of the constituent--quark parameters from
  Jefferson Lab experiments on pion form factor

abstract:
  The charge form factor of the pion is calculated for momentum transfer range
of Jefferson Lab experiments. The approach is based on the instant form of the
relativistic Hamiltonian dynamics. It is shown that the form-factor dependence
on the choice of the model for quark wave function in pion is weak, while the
dependence on the constituent--quark mass is rather significant. It is possible
to estimate the mass of constituent quark and the sum of anomalous magnetic
moments of $u$- and $\bar d$- quarks from the JLab experiments.


title: Vilkovisky-DeWitt Effective Potential and the Higgs-Mass Bound

abstract:
  We compute the Vilkovisky-DeWitt effective potential of a simplified version
of the Standard Electroweak Model, where all charged boson fields as well as
the bottom-quark field are neglected. The effective potential obtained in this
formalism is gauge-independent. We derive from the effective potential the mass
bound of the Higgs boson. The result is compared to its counterpart obtained
from the ordinary effective potential.


title: Black holes with magnetic charge and quantized mass

abstract:
  We examine the issue of magnetic charge quantization in the presence of black
holes. It is pointed out that quantization of magnetic charge can lead to the
mass quantization for magnetically charged black holes. We also discuss some
implications for the experimental searches of magnetically charged black holes.


title: High Temperature Symmetry Breaking via Flat Directions

abstract:
  We show that the natural presence of flat directions in supersymmetric
theories allows for nonrestoration of global and/or gauge symmetries. This has
important cosmological consequences for supersymmetric GUTs and in particular
it offers a solution of the monopole problem.


title: Chern-Simons Violation of Lorentz and PCT Symmetries in Electrodynamics

abstract:
  Recently proposed Lorentz-PCT noninvariant modifications of electromagnetism
are reviewed. Their experimental consequences are described, and it is argued
that available data decisively rules out their occurrence in Nature.


title:
Some Remarks on Theories with Large Compact Dimensions and TeV-Scale
  Quantum Gravity

abstract:
  We comment on some implications of theories with large compactification radii
and TeV-scale quantum gravity. These include the behavior of high-energy
gravitational scattering cross sections and consequences for ultra-high-energy
cosmic rays and neutrino scattering, the question of how to generate naturally
light neutrino masses, the issue of quark-lepton unification, the equivalence
principle, and the cosmological constant.


title: On Big Bang Relics, the Neutrino Mass and the Cosmic Ray Spectrum

abstract:
  It is shown that high energy features of the cosmic ray spectrum, in
particular the kink around 4 PeV and the corresponding change in spectral
index, may be explained from interactions between highly energetic protons and
relic Big Bang antineutrinos, if the latter have a rest mass of about 0.4
eV/$c^2$. This explanation is supported by experimental data from extensive
air-shower experiments.


title:
Illuminating dark matter and primordial black holes with interstellar
  antiprotons

abstract:
  Interstellar antiproton fluxes can arise from dark matter annihilating or
decaying into quarks or gluons that subsequently fragment into antiprotons.
Evaporation of primordial black holes also can produce a significant antiproton
cosmic-ray flux. Since the background of secondary antiprotons from spallation
has an interstellar energy spectrum that peaks at $\sim 2\gev$ and falls
rapidly for energies below this, low-energy measurements of cosmic antiprotons
are useful in the search for exotic antiproton sources. However, measurement of
the flux near the earth is challenged by significant uncertainties from the
effects of the solar wind. We suggest evading this problem and more effectively
probing dark-matter signals by placing an antiproton spectrometer aboard an
interstellar probe currently under discussion. We address the experimental
challenges of a light, low-power-consuming detector, and present an initial
design of such an instrument. This experimental effort could significantly
increase our ability to detect, and have confidence in, a signal of exotic,
nonstandard antiproton sources. Furthermore, solar modulation effects in the
heliosphere would be better quantified and understood by comparing results to
inverse modulated data derived from existing balloon and space-based detectors
near the earth.


title: Neutrino Masses in R Parity Violating Supersymmetry

abstract:
  We discuss a model for neutrino masses and mixings based on R parity
violating Yukawa couplings. The model requires no right-handed neutrinos. It
accommodates the SuperKamiokande data on atmospheric neutrinos and successfully
relates this data to the mass difference for solar neutrinos in the small-angle
MSW solution. We obtain an unexpected testable pattern for the three neutrino
flavors.


title: One Theorist's Perspective on Four Eras of Electron-Proton Scattering

abstract:
  A transcription with minor alterations of the talk presented to honor Sid
Drell on the occasion of his retirement.


title: Polarized observables to probe Z' at the e+e- linear collider

abstract:
  We study the sensitivity to the Z' couplings of the processes $e^+e^-\to
l^+l^-,\bar{b}b$ and $\bar{c}c$ at the linear collider with $\sqrt{s}=500 GeV$
with initial beam polarization, for typical extended model examples. To this
aim, we use suitable integrated, polarized, observables directly related to the
helicity cross sections that carry information on the individual Z' chiral
couplings to fermions. We discuss the derivation of separate, model-independent
limits on the couplings in the case of no observed indirect Z' signal within
the expected experimental accuracy. In the hypothesis that such signals were,
indeed, observed we assess the expected accuracy on the numerical determination
of such couplings and the consequent range of Z' masses where the individual
models can be distinguished from each other as the source of the effect.


title: A New Parametrization of Polarized Parton Distribution Functions

abstract:
  Requiring the positivity and counting rule, we propose a new parametrization
of the polarized parton distribution which reproduce the data well. We found
that the NLO analysis is absolutely necessary to extract the correct
information on the polarized gluon distributions. The calculated results of
$x\Delta d_v(x)$ and $\Delta d_v(x)/d_v(x)$ seem to be consistent with the SMC
data at $Q^2=$10GeV$^2$.


title: Double Top Production at Hadronic Colliders

abstract:
  We calculate the contribution of anomalous top-quark interaction with a
gluon, photon, and $Z$-boson (FCNC) to $t \bar t$ pair production in hadronic
collisions. Using the current data from Run~1 of the Tevatron we evaluate the
upper limit on the the anomalous coupling of $t$-quark with gluon,
$|\kappa_g/\Lambda| \le 0.52$ TeV$^{-1}$. We examine the production of double
top ($t t$ or $\bar t \bar t$) at hadronic colliders as a result of FCNC
interactions of the top quark. It is shown that the study of such reactions at
LHC collider makes possible to obtain the constraint on strength of coupling at
the level of $|\kappa_g /\Lambda| \le 0.09$ TeV$^{-1}$.


title:
New Constraint on Weak CP Phase, Rephasing Invariant and Maximal CP
  Violation

abstract:
  By using the relation between CP-violation phase and the mixing angles in
Cabibbo-Kobayashi-Maskawa matrix postulated by us before, the rephasing
invariant is recalculated. Furthermore, the problem about maximal CP violation
is discussed. We find that the maximal value of Jarlskog's invariant is about
0.038. And it presents at alpha=1.239, beta=1.574 and gamma=0.327 in triangle
db.


title:
Effect of Non-Orthogonality of Residues in the Wigner-Weisskopf model on
  Regeneration for the Neutral $K$ Meson system

abstract:
  We review the application of the Wigner-Weisskopf model to the two-channel
decay problem for the neutral $K$ meson system in the resolvent formalism. The
residues in the pole approximation are not orthogonal, leading to additional
interference terms in the $K_S-K_L 2\pi$ channel. We show that these terms lead
to non-trivial changes in the exit beam in comparison to the result calculated
with the assumptions of Lee, Oehme and Yang, and Wu and Yang, corresponding to
semigroup evolution for which the pole residues are orthogonal, and hence
appear to rule out the applicability of the Wigner-Weisskopf model for the
computation of regeneration in the neutral $K$ meson system.


title: Search for Exotic Muon Decays

abstract:
  Recently, it has been proposed that the observed anomaly in the time
distribution of neutrino induced reactions, reported by the KARMEN
collaboration, can be interpreted as a signal from an exotic muon decay branch
mu+ to e+ X. It has been shown that this hypothesis gives an acceptable fit to
the KARMEN data if the boson X has a mass of m_X=103.9MeV/c^2, close to the
kinematical limit. We have performed a search for the X particle by studying
for the first time the very low energy part of the Michel spectrum in mu+
decays. Using a HPGe detector setup at the muE4 beamline at PSI we find
branching ratios BR(mu+ to e+ X)<5.7e-4 (90% C.L.) for most of the region
103MeV/c^2<m_X<105MeV/c^2.


title:
Associated stop Higgs Production at the Linear Collider and Extraction
  of the stop Parameters

abstract:
  We calculate stop stop Higgs production at the linear collider.
  Combining the measurements from the pair production of the lightest stop and
that of the mass of the Higgs we show how, in a scenario where only the
lightest stop and the lightest Higgs were accessible, one could extract the
mass of the heavier stop and infer some useful information on the SUSY
parameters.


title: Weak phases $\gamma$ and $\alpha$ from $B^+$, or $B^0$ and $B_s$ decays

abstract:
  An improved flavor SU(3) method is presented for determining the weak angle
$\gamma$ of the unitarity triangle using decay rates for $B^+\to K\pi, B^+\to
K^+\bar K^0$ and $B^+\to \pi^+\eta$ (or $B^0\to K\pi$ and $B_s\to K \pi$),
their CP-conjugate modes and the CP-averaged rate for $B^\pm\to\pi^\pm\pi^{0}$.
Rescattering (color-suppressed) contribution in $B^+(B^0)\to K\pi$, for which
an improved bound is obtained, is subtracted away. The only significant SU(3)
breaking effects are accounted for in the factorization approximation of tree
amplitudes. The weak angle $\alpha$ is obtained as a byproduct.


title: Muon Capture and the pseudoscalar form factor of the nucleon

abstract:
  We summarize recent work on muon capture and the pseudoscalar form factor of
the nucleon.


title: Collider Signatures of New Large Space Dimensions

abstract:
  Recently, Arkani-Hamed, Dimopoulos, and Dvali have proposed that there are
extra compact dimensions of space, accessible to gravity but not to ordinary
matter, which could be macroscopically large. In this letter, we argue that
high-energy collider processes in which gravitons are radiated into these new
dimensions place significant, model-independent constraints on this picture. We
present the constraints from anomalous single photon production at e+e-
colliders and from monojet production at hadron colliders.


title:
Measure of $\pi$'s and $\Lambda$'s emitter radius via Bose-Einstein and
  Fermi-Dirac Statistics

abstract:
  This report summarises the recent studies of the Bose-Einstein Correlations
(BEC) carried out by the four LEP experiments using hadronic Z$^0$ decay events
and $e^+ e^-$ reactions leading to the WW decay final states. The three
identical charged pion systems $\pi^{\pm} \pi^{\pm} \pi^{\pm}$ have been
studied by OPAL with $4 \times 10^6$ hadronic Z$^0$ decays events. The genuine
three-pion correlations corrected for Coulomb effects, were separated from the
known two-pion correlations by a novel subtraction procedure using the data
events themselves. From this analysis a value of $\mathrm r_3 = 0.580 \pm 0.029
\~fm $ was obtained. The recent L3 study of the two-dimensional two-pion BEC is
also discussed. In this study, which utilised the longitudinal co-moving
system, evidence is given for a non-spherical di-pion emitter shape where the
ratio of the minor to major axes is found to be $0.74 \pm 0.09$. Next we
summarise the experimental aspects of the BEC and colour reconnection phenomena
in W-pair events at LEP and their contribution to the systematic error
associated with the M$_W$ measurements. Finally we describe the first attempts
to evaluate the $\Lambda\Lambda$($\bar{\Lambda}\bar{\Lambda}$) emitter
dimension via the Pauli exclusion principle with a combined result of $ \mathrm
R_{\Lambda\Lambda} = 0.14 ^{+ 0.07}_{-0.03} ~~{\mathrm fm} taup


title: Lepton mass matrices from a quark-lepton analogy

abstract:
  We study the implications of having a similarity between quark and lepton
mixing in the Dirac sector of the Standard Model plus the right-handed
neutrino. This enable us to describe all masses and mixings in the Dirac sector
in terms of only five parameters: three mass scales $m_b$, $m_{\tau}$ and
$m_t$, one parameter $\lambda$ describing all the mixings, and a CP violating
phase in the quark sector. Then, from experimental data on neutrino masses and
mixings, we extract the heavy neutrino mass matrix. The approach considered,
although does not contraddict Grand Unified Theories, can help to find other
theoretical models of fermion masses.


title: $k_T$ and threshold resummations

abstract:
  We demonstrate that both the $k_T$ and threshold resummations can be
performed in the Collins-Soper resummation formalism by evaluating soft gluon
emissions with infrared cutoffs for the longitudinal and transverse loop
momenta, respectively. The reason the $k_T$ resummation for a parton
distribution function leads to suppression in the large $b$ region, $b$ being
the conjugate variable of parton transverse momentum $k_T$, and the threshold
resummation leads to enhancement in the large $N$ limit, $N$ being the moment
of a distribution function, is a consequence of opposite directions of
double-logarithm evolutions. The $k_T$ and threshold resummations for an
energetic final-state jet give suppression. The switch of the threshold
resummation from enhancement to suppression is attributed to a nonvanishing jet
invariant mass. In the same framework we derive a unification of the $k_T$ and
threshold resummations for a parton distribution function by requiring infrared
cutoffs for both longitudinal and transverse loop momenta. This unified
resummation exhibits suppression at large $b$, similar to the $k_T$
resummation, and exhibits enhancement at small $b$, similar to the threshold
resummation.


title: The Supersymmetric Standard Model

abstract:
  This set of lectures introduces at an elementary level the supersymmetric
Standard Model and discusses some of its phenomenological properties.
  (Lectures given by J. Louis at the summer school ``Grundlagen und neue
Methoden der theoretischen Physik'', Saalburg, 1996.)


title: Completely Automated Calculations of Multi-Loop Diagrams

abstract:
  The computation of higher order processes very often involves a large number
of diagrams. In addition, it is in general not possible to solve the occurring
integrals explicitly and expansions in small quantities have to be performed.
This makes it necessary to automate the calculations as much as possible. A
program package will be described which generates automatically the Feynman
diagrams, manipulates the expressions in the desired way and performs the
computation. As a physical application O(\alpha\alpha_s) corrections to the
decay rate of the $Z$ boson into bottom quarks are discussed.


title:
Hunting a Light U(1)_B Gauge Boson Coupled to Baryon Number in Collider
  Experiments

abstract:
  We analyze several signals at HERA and the Tevatron of a light $U(1)_B$ gauge
boson ($\gamma_B$) coupling to baryon number. We show that the study of the
production of $b \bar{b}$ pairs at the (upgraded) Tevatron can exclude
$\gamma_B$ with masses ($m_B$) in the range $40 \lesssim m_B \lesssim 300$ GeV
for $\gamma_B$ couplings ($\alpha_B$) greater than $2 \times 10^{-2}$ ($3
\times 10^{-3}$). We also show that the HERA experiments cannot improve the
present bounds on $\gamma_B$. Moreover, we demonstrate that the production at
HERA and the Tevatron of di--jet events with large rapidity gaps between the
jets cannot be explained by the existence of a light $\gamma_B$.


title: Neutrino Magnetic Moment and Solar Neutrino Experiments

abstract:
  We have studied the effect of a non-vanishing neutrino magnetic moment \
($\mu_{\nu}$) on the $\nu_{\rm x}$ ({x=$e,\mu,\tau$}) elastic scattering off
electrons for the Super-Kamiokande detector. The bounds on the $\mu_{\nu}$ we
have obtained are comparable to that extracted from laboratory experiments.
Furthemore, we outline the potential of the Borexino experiment which may be
sensitive to neutrino magnetic moments $\lsim 10^{-10}\mu_B$. In our analysis
we have considered both cases of Majorana and Dirac neutrinos.


title: Diffraction at small M^2/Q^2 in the QCD dipole picture

abstract:
  Using the QCD dipole picture of BFKL dynamics, the quasi elastic component of
the diffractive gamma*-dipole cross-section, dominating at small M^2/Q^2, is
calculated.


title: The Likelihood of DCC Formation

abstract:
  We estimate the probability that a disoriented chiral condensate forms during
the spherical expansion of a hot medium described by the linear sigma model.


title:
The Chiral Phase Transition at High Baryon Density from Nonperturbative
  Flow Equations

abstract:
  We investigate the QCD chiral phase transition at high baryon number density
within the linear quark meson model for two flavors. The method we employ is
based on an exact renormalization group equation for the free energy. Truncated
nonperturbative flow equations are derived at nonzero chemical potential and
temperature. Whereas the renormalization group flow leads to spontaneous chiral
symmetry breaking in vacuum, we find a chiral symmetry restoring first order
transition at high density. Combined with previous investigations at nonzero
temperature, the result implies the presence of a tricritical point with
long--range correlations in the phase diagram.


title: Theory of Spin Effects in Hard Hadronic Reactions

abstract:
  I discuss the present situation with regard to a variety of theoretical
topics in hadronic spin physics: (a) global analysis of the g1
data---positivity at leading and next-to-leading order, renormalisation-scheme
dependence, parametrisation, and hyperon beta-decays; (b) items from the realm
of transverse spin---twist-three effects, single-spin asymmetries, and
transversity; and finally (c) recent developments in understanding the Q^2
evolution of orbital angular momentum.


title:
Soft and Hard Pomeron in the Structure Function of the Proton at Low x
  and Low Q^2

abstract:
  We study inclusive electroproduction on the proton at low $x$ and low $Q^2$
using a soft and a hard Pomeron. The contribution of the soft Pomeron is based
on the Stochastic Vacuum Model, in which a nonperturbative dipole-dipole cross
section can be calculated by means of a gauge invariant gluon field strength
correlator. To model the hard Pomeron exchange we phenomenologically extend the
leading order evolution of a power-behaved structure function, $F_2 \propto
x^{- \lambda}$, proposed by L\'opez and Yndur\'ain. This extension allows to
consider both the case $Q^2 = 0$ and the region of higher $Q^2$ on the basis of
the same parametrization. A good simultaneous fit to the data on $F_2$ and on
the cross section $\sigma_{\gamma p}$ of real photoproduction is obtained for
$\lambda=0.37$. With four parameters we achieve a $\chi^2/\textrm{d.o.f.} =
0.98$ for 222 data points. In addition, we use our model of the inclusive
$\gamma^{\ast} p$ interaction to compute the longitudinal structure function
$F_L$.


title: On Kaluza-Klein States from Large Extra Dimensions

abstract:
  We consider the novel Kaluza-Klein (KK) scenario where gravity propagates in
the $4+n$ dimensional bulk of spacetime, while gauge and matter fields are
confined to the 3+1 dimensional world-volume of a brane configuration. For
simplicity we assume compactification of the extra $n$ dimensions on a torus
with a common scale $R$, and identify the massive KK states in the
four-dimensional spacetime. For a given KK level $\vec{n}$ there are one spin-2
state, $(n-1)$ spin-1 states and $n(n-1)/2$ spin-0 states, all mass-degenerate.
We construct the effective interactions between these KK states and ordinary
matter fields (fermions, gauge bosons and scalars). We find that the spin-1
states decouple and that the spin-0 states only couple through the dilaton
mode. We then derive the interacting Lagrangian for the KK states and Standard
Model fields, and present the complete Feynman rules. We discuss some low
energy phenomenology for these new interactions for the case when 1/R is small
compared to the electroweak scale, and the ultraviolet cutoff of the effective
KK theory is on the order of 1 TeV.


title: Heavy flavour contributions to the deep inelastic sum rules

abstract:
  We have calculated the first and second order corrections to several deep
inelastic sum rules which are due to heavy flavour contributions. A comparison
is made with the existing perturbation series which has been computed up to
third order for massless quarks only. In general it turns out that the effects
of heavy quarks are very small except when $Q \sim m$ or $Q \gg m$. Here $Q$
and $m$ denote the virtual mass of the vector boson and the mass of the heavy
quark, respectively. For $Q \gg m$ the radiative corrections reveal large
logarithms of the type $\ln Q^2/m^2$ which have to be absorbed in the running
coupling constant so that the number of light flavours $n_f$ is enhanced by one
unit. However this has to happen at much larger values of Q i.e. $Q \sim 6.5~
m$ than one usually assumes for the flavour thresholds which appear in the
running coupling constant. An alternative description for the heavy flavour
dependence of the running coupling constant in the context of the MOM-scheme is
discussed.


title:
Vacuum oscillations and the distorted solar neutrino spectrum observed
  by Superkamiokande

abstract:
  The excess of solar-neutrino events above 13 MeV that has been recently
observed by Superkamiokande can be explained by vacuum oscillations (VO). If
the boron neutrino flux is 20% smaller than the standard solar model (SSM)
prediction and the chlorine signal is assumed 30% (or 3.5 sigmas) higher than
the measured one, there exists a VO solution that reproduces both the observed
boron neutrino spectrum, including the high energy distortion, and the other
measured neutrino rates. This solution might already be testable by the
predicted anomalous seasonal variation of the gallium signal. Its most distinct
signature, a large anomalous seasonal variation of Be7 neutrino flux, can be
easily observed by the future detectors, BOREXINO and LENS.


title:
New origin for approximate symmetries from distant breaking in extra
  dimensions

abstract:
  The recently proposed theories with TeV-scale quantum gravity remove the
usual ultraviolet desert between $\sim 10^{3} - 10^{19}$ GeV where effective
field theory ideas apply. Consequently, the success of the desert in explaining
approximate symmetries is lost, and theories of flavor, neutrino masses, proton
longevity or supersymmetry breaking, lose their usual habitat. In this paper we
show that these ideas can find a new home in an infrared desert: the large
space in the extra dimensions. The main idea is that symmetries are
primordially exact on our brane, but are broken at O(1) on distant branes. This
breaking is communicated to us in a distance-suppressed way by bulk messengers.
We illustrate these ideas in a number of settings: 1) We construct theories for
the fermion mass hierarchy which avoid large FCNC's. 2) We re-iterate that
proton stability can arise if baryon number is gauged in the bulk. 3) We study
experimental constraints on light gauge fields and scalars in the bulk. 4) We
remark that the same ideas can be used to explain small neutrino masses, and
hierarchical supersymmetry breaking. 5) We construct a theory with bulk
technicolor, avoiding the difficulties with extended technicolor. There are
also interesting experimental signals of these ideas: 1) Attractive or
repulsive, isotope dependent sub-millimeter forces $\sim 10^6$ times
gravitational strength, from the exchange of light bulk particles. 2) Novel
Higgs decays to light generation fermions plus bulk scalars. 3) Collider
production of bulk vector and scalar fields, leading to large $\gamma$ or jet+
missing energy signals.


title: Vector Quark Model and B to X_s gamma Decay

abstract:
  We study the $B$ meson radiative decay $B \to X_s \gamma$ in the vector quark
model. Deviation from the Standard Model arises from the non-unitarity of the
charged current KM matrix and related new FCNC interactions. We establish the
relation between the non-unitarity of charged current mixing matrix and the
mixing among the vector quark and the ordinary quarks. We also make explicitly
the close connection between this non-unitarity and the flavor changing neutral
currents. The complete calculation including leading logarithmic QCD correction
is carefully carried out. Using the most updated data and the NLO theoretical
calculation, the branching fraction of the observed $B$ meson radiative decay
places a limit on the mixing angles as stringent as that from the process $B\to
X \mu\bar\mu$.


title:
Physics Implications of Flat Directions in Free Fermionic Superstring
  Models II: Renormalization Group Analysis

abstract:
  We continue the investigation of the physics implications of a class of flat
directions for a prototype quasi-realistic free fermionic string model (CHL5),
building upon the results of the previous paper in which the complete mass
spectrum and effective trilinear couplings of the observable sector were
calculated to all orders in the superpotential. We introduce soft supersymmetry
breaking mass parameters into the model, and investigate the gauge symmetry
breaking patterns and the renormalization group analysis for two representative
flat directions, which leave an additional $U(1)'$ as well as the SM gauge
group unbroken at the string scale. We study symmetry breaking patterns that
lead to a phenomenologically acceptable $Z-Z'$ hierarchy, $M_{Z^{'}} \sim {\cal
O}(1~{\rm TeV})$ and $ 10^{12}~{\rm GeV}$ for electroweak and intermediate
scale $U(1)^{'}$ symmetry breaking, respectively, and the associated mass
spectra after electroweak symmetry breaking. The fermion mass spectrum exhibits
unrealistic features, including massless exotic fermions, but has an
interesting $d$-quark hierarchy and associated CKM matrix in one case. There
are (some) non-canonical effective $\mu$ terms, which lead to a non-minimal
Higgs sector with more than two Higgs doublets involved in the symmetry
breaking, and a rich structure of Higgs particles, charginos, and neutralinos,
some of which, however, are massless or ultralight. In the electroweak scale
cases the scale of supersymmetry breaking is set by the $Z^{'}$ mass, with the
sparticle masses in the several TeV range.


title: Indirect Collider Signals for Extra Dimensions

abstract:
  A recent suggestion that quantum gravity may become strong near the weak
scale has several testable consequences. In addition to probing for the new
large (submillimeter) extra dimensions associated with these theories via
gravitational experiments, one could search for the Kaluza Klein towers of
massive gravitons which are predicted in these models and which can interact
with the fields of the Standard Model. Here we examine the indirect effects of
these massive gravitons being exchanged in fermion pair production in \epem
annihilation and Drell-Yan production at hadron colliders. In the latter case,
we examine a novel feature of this theory, which is the contribution of gluon
gluon initiated processes to lepton pair production. We find that these
processes provide strong bounds, up to several TeV, on the string scale which
are essentially independent of the number of extra dimensions. In addition, we
analyze the angular distributions for fermion pair production with spin-2
graviton exchanges and demonstrate that they provide a smoking gun signal for
low-scale quantum gravity which cannot be mimicked by other new physics
scenarios.


title: Flavour Universal Dynamical Electroweak Symmetry Breaking

abstract:
  The top condensate see-saw mechanism of Dobrescu and Hill allows electroweak
symmetry to be broken while deferring the problem of flavour to an electroweak
singlet, massive sector. We provide an extended version of the singlet sector
that naturally accommodates realistic masses for all the standard model
fermions, which play an equal role in breaking electroweak symmetry. The models
result in a relatively light composite Higgs sector with masses typically in
the range of (400-700)~GeV. In more complete models the dynamics will
presumably be driven by a broken gauged family or flavour symmetry group. As an
example of the higher scale dynamics a fully dynamical model of the quark
sector with a GIM mechanism is presented, based on an earlier top condensation
model of King using broken family gauge symmetry interactions (that model was
itself based on a technicolour model of Georgi). The crucial extra ingredient
is a reinterpretation of the condensates that form when several gauge groups
become strong close to the same scale. A related technicolour model of Randall
which naturally includes the leptons too may also be adapted to this scenario.
We discuss the low energy constraints on the massive gauge bosons and scalars
of these models as well as their phenomenology at the TeV scale.


title: Birth of Neutrino Oscillation

abstract:
  This is a brief presentation of historical introduction to the theoretical
concept of neutrino oscillation during the early stage up to 60's. (Openig
address at the Europhysics NEUTRINO OSCILLATION WORKSHOP (NOW' 98), 7-9 Sept.
1998, Amsterdam.


title: The Arrival of Charm

abstract:
  Some of the theoretical motivations and experimental developments leading to
the discovery of charm are recalled.


title: High-Multiplicity Processes (Theoretical status)

abstract:
  We wish to demonstrate that investigation of asymptotically high multiplicity
(AHM) hadron reactions may solve, or at least clear up, a number of problems
unsolvable by other ways. We would lean upon the idea: (i) the entropy is
proportional to multiplicity and, by this reason, at the AHM domain one may
expect the equilibrium final state and (ii) the high-multiplicity processes
becomes hard. Last one means that the nonperturbative corrections are frozen
during this processes and the QCD predictions are available for them.


title: $\Upsilon$ Polarization at HERA-$B$

abstract:
  The production of $\Upsilon$ mesons in fixed target $pN$ collisions is
considered. It is shown that Non-Relativistic QCD predicts $\Upsilon$ states to
be produced with sizeable transverse polarization. The possibility of a
measurement of the $\Upsilon$ polarization at the HERA-$B$ experiment is
discussed.


title:
Effects of CP Violation on Event Rates in the Direct Detection of Dark
  Matter

abstract:
  A full analytic analysis of the effects of CP violating phases on the event
rates in the direct detection of dark matter in the scattering of neutralinos
from nuclear targets is given. The analysis includes CP violating phases in
softly broken supersymmetry in the framework of the minimal supersymmetric
standard model (MSSM) when generational mixings are ignored. A numerical
analysis shows that large CP violating phases including the constraints from
the experimental limits on the neutron and the electron electric dipole moment
(EDM) can produce substantial effects on the event rates in dark matter
detectors.


title: Atmospheric and Solar Neutrino Masses from Horizontal U(1) Symmetry

abstract:
  We study the neutrino mass matrix in supersymmetric models in which the quark
and charged lepton mass hierarchies and also the suppression of baryon or
lepton number violating couplings are all explained by horizontal $U(1)_X$
symmetry. It is found that the neutrino masses and mixing angles suggested by
recent atmospheric and solar neutrino experiments arise naturally in this
framework which fits in best with gauge-mediated supersymmetry breaking with
large $\tan\beta$. This framework highly favors the small angle MSW oscillation
of solar neutrinos, and determine the order of magnitudes of all the neutrino
mixing angles and mass hierarchies.


title: Quark Propagation in a Quark-Gluon Plasma with Gluon Condensate

abstract:
  We present a calculation of the thermal quark propagator taking the gluon
condensate above the critical temperature into account. The quark dispersion
relation following from this propagator, describing two massive modes, is
discussed.


title: Reduction of multi-leg loop integrals

abstract:
  I give an efficient algorithm for the reduction of multi-leg one-loop
integrals of rank one. The method combines the basic ideas of the spinor
algebra approach with the dual vector approach and is applicable to box
integrals or higher point integrals, if at least one external leg is massless.
This method does not introduce Gram determinants in the denominator. It
completes an algorithm recently given by R. Pittau.


title: On the size of isospin violation in low-energy pion-nucleon scattering

abstract:
  We present an analysis of isospin-breaking effects in threshold pion-nucleon
scattering due to the light quark mass difference and the dominant virtual
photon effects. We discuss the deviation from various relations, which are
exact in the isospin limit. The size of the isospin-violating effects in the
relations involving the isovector $\pi N$ amplitudes is typically of the order
of one percent. We also find a new remarkably large effect $(\sim 40%)$ in an
isoscalar triangle relation connecting the charged and neutral pion scattering
off protons.


title:
Accelerated convergence of perturbative QCD by optimal conformal mapping
  of the Borel plane

abstract:
  The technique of conformal mappings is applied to enlarge the convergence of
the Borel series and to accelerate the convergence of Borel-summed Green
functions in perturbative QCD. We use the optimal mapping, which takes into
account the location of all the singularities of the Borel transform as well as
the present knowledge about its behaviour near the first branch points. The
determination of \alpha_{s}(m_{\tau}) from the hadronic decay rate of the
\tau-lepton is discussed as an illustration of the method.


title: Resolved virtual photons in the small $x$ domain

abstract:
  It has been found that recent results on forward jet production from deep
inelastic scattering can neither be reproduced by models which are based on
leading order $\alpha_s$ QCD matrix elements and parton showers nor by
next-to-leading order calculations. The measurement of forward jet cross
sections has been suggested as a promising probe of new small $\xbj$ parton
dynamics and the question is whether these data provide an indication of this.
The same question arises for other experimental data in deep inelastic
scattering at small $\xbj$ which can not be described by conventional models
for deep inelastic scattering. In this paper the influence of resolved photon
processes has been investigated and it has been studied to what extent the
inclusion of such processes in addition to normal deep inelastic scattering
leads to agreement with data. It is shown that two DGLAP evolution chains from
the hard scattering process towards the proton and the photon, respectively,
are sufficient to describe effects, observed in the HERA data, which have been
attributed to BFKL dynamics.


title: Higgs sector CP-violation at the electroweak phase transition

abstract:
  We consider explicit and spontaneous CP-violation related to the profile of
the two Higgs doublets at the MSSM electroweak phase transition. We find, in
accordance with previous results, that in principle spontaneous CP-violation
could exist in the MSSM at finite temperatures, but when the constraints from
experiment and the strength of the transition are taken into account, the
relevant region of the parameter space is rather restricted. Nevertheless, we
show that in this small region, perturbative estimates need not be reliable,
and non-perturbatively the region might be slightly larger (or smaller). To
allow for more precise perturbative studies and for a lattice study of the
non-perturbative corrections, we construct an effective 3d theory for the light
stops and the two Higgses in the regime of large mQ. The 3d theory involves
CP-violating parameters and allows to determine CP-odd observables.


title:
One-Photon Transitions between Heavy Baryons in a Relativistic
  Three-Quark Model

abstract:
  We study one-photon transitions between heavy baryon states in the framework
of a relativistic three-quark model. We calculate the one-photon transition
rates for ground-state to ground-state transitions and for some specific
excited state to ground-state transitions. Our rate predictions for the most
important transitions are: $\Gamma(\Sigma^{+}_{c}\to \Lambda_c^+\gamma)=
60.7\pm 1.5 $ KeV, $\Gamma(\Xi^{'+}_{c}\to \Xi_c^+\gamma) = 12.7\pm 1.5$ KeV,
$\Gamma(\Lambda_{c1}(2593)\to\Lambda_c^+\gamma)=104.3\pm 1.3$ KeV.


title: Q-Balls and the Proton Stability in Supersymmetric Theories

abstract:
  Abelian non-topological solitons with Baryon and/or Lepton quantum numbers
naturally appear in the spectrum of the minimal supersymmetric standard model.
They arise as a consequence of the existence of flat directions in the
potential lifted by non renormalizable operators and SUSY breaking. We examine
the conditions that these operators should satisfy in order to ensure proton
stability and present a realistic string model which fulfils these
requirements. We further identify a generic U(1) breaking term in the scalar
potential and discuss its effect of rendering Q-balls unstable.


title: Interfering QCD/QED Vacuum Polarization

abstract:
  Vacuum polarization mediated by quark loops is susceptible to external
electromagnetic fields as well as to the QCD vacuum structure. Employing the
stochastic vacuum model, we calculate the modification of the one-loop
Euler-Heisenberg effective action due to stochastic color fields with the
Fock-Schwinger technique. Our results indicate nonperturbative light quark
contributions of the same order of magnitude as the usual QED terms. Various
theoretical and experimental implications are discussed in this progress
report.


title: New Higgs Couplings at e+ e- and Hadronic Colliders

abstract:
  We examine the potentiality of both CERN LEP and Fermilab Tevatron colliders
to establish bounds on new couplings involving the bosonic sector of the
standard model. We pay particular attention to the anomalous Higgs interactions
with $\gamma$, $W^{\pm}$ and $Z^0$. A combined exclusion plot for the
coefficients of different anomalous operators is presented. The sensitivity
that can be achieved at the Next Linear Collider and at the upgraded Tevatron
is briefly discussed.


title: Three Jet Events and New Strong Couplings at LEP and NLC

abstract:
  We study the effects of new dimension--6 operators, resulting from a general
$SU(3)_C \otimes SU(2)_L \otimes U(1)_Y$ invariant effective Lagrangian, on
three jet production at LEP and at the Next Linear Collider. Contributions to
the total event rate and to some event shape variables are analysed in order to
establish bounds on these operators.


title: Quintessential Difficulties

abstract:
  An alternative to a cosmological constant is quintessence, defined as a
slowly-varying scalar field potential V(\phi). If quintessence is
observationally significant, an epoch of inflation is beginning at the present
epoch, with \phi the slowly-rolling inflaton field. In contrast with ordinary
inflation, quintessence seems to require extreme fine tuning of the potential
V(\phi). The degree of fine-tuning is quantified in various cases.


title: CP Violation in Non-Leptonic Omega^- Decays

abstract:
  We estimate the size of the CP-violating rate asymmetry for the decay Omega^-
-> Cascade + pion. Within the standard model we find a value of 2 x 10^(-5),
and it could be as much as ten times larger if new physics is responsible for
CP violation. Even though our calculation suffers from the usual uncertainty in
the estimate of hadronic matrix elements, we find a rate asymmetry that is
significantly larger than the corresponding one for octet-hyperon decays.


title: Duality-Violating 1/m_Q Effects in Heavy Quark Decay

abstract:
  I identify a source of \Lambda_{QCD}/m_Q corrections to the assumption of
quark-hadron duality in the application of heavy quark methods to inclusive
heavy quark decays. These corrections could substantially affect the accuracy
of such methods in practical applications and in particular compromise their
utility for the extraction of the Cabibbo-Kobayashi-Maskawa matrix element
V_{cb}.


title: Flavor Violation in Theories with TeV Scale Quantum Gravity

abstract:
  We study the effects of possible flavor-violating operators in theories with
the TeV scale quantum gravity, in which the ordinary matter is localized on a
3-brane embedded in the space with $N$ extra dimensions, whereas gravity
propagates in the bulk. These operators are scaled by the fundamental Planck
mass $M_{Pf}\sim$ TeV and must be suppressed by the gauge family symmetries. We
study suppression of the most dangerous and model-independent operators.
Several points emerge. First, we show that the Abelian symmetries can not do
the job and one has to invoke non-Abelian $U(2)_F$ (or $U(3)_F$) symmetries.
However, even in this case there emerge severe restrictions on the fermion
mixing pattern and the whole structure of the theory. In order not to be
immediately excluded by the well-known bounds, the horizontal gauge fields {\it
must} be the bulk modes, like gravitons. For the generic hierarchical breaking
pattern the four-fermion operators induced by the tree-level exchange of the
bulk gauge fields are unsuppressed for $N = 2$. For $N > 3$ the suppression
factor goes as a square of the largest $U(2)_F$-non-invariant Yukawa coupling,
which implies the lower bound $M_{Pf} > 10$ TeV or so from the $K^0 - \bar K^0$
system. Situation is different in the scenarios when flavor Higgs fields live
on a ($3 + N'$)-brane of lower dimensionality than the gauge fields. The
further suppression of gauge-mediated operators can be achieved by an explicit
construction: for instance, if $U(2)_F$ is broken by a vacuum expectation value
of the doublet, the troublesome operators are suppressed in the leading order,
due to custodial SO(4) symmetry of the Higgs-gauge quartic coupling.


title: Bi-maximal Lepton Flavor Mixing Matrix and Neutrino Oscillation

abstract:
  Recently, many authors showed that if the solar and atmospheric neutrino data
are both described by maximal mixing vacuum oscillations at the relevant mass
scale, then there exists a unique bi-maximal lepton mixing matrix for three
neutrino flavors. We construct the lepton mass matrices from the symmetry
principle so that maximal mixings for the atmospheric and the solar neutrino
vacuum oscillations are naturally generated. Although the hierarchical patterns
of the lepton sector are quite different from each other, we show how two
different mass matrices suggested in this work can be generated in a unified
way. We also give comments on possible future tests of the bi-maximal lepton
mixing matrix.


title:
The proton structure function and a soft Regge Dipole Pomeron: a test
  with recent data

abstract:
  A recently published soft Regge Dipole Pomeron model intended for all $x$ and
$Q^2$ is proved to give a good agreement with (non fitted) recent HERA data
from ZEUS (SVX95) on the protonstructure function $F_2^p(x,Q^2)$ at low $Q^2$
and low $x$. The model also reproduces (without fit) the recently estimated
experimental derivatives ${\partial F_2^p\over\partial\ell n Q^2}$ and
${\partial \ell n F_2^p\over\partial\ell n (1/x)}$ in a wide $x$ and
$Q^2$-region.


title: An Alternative to See-Saw

abstract:
  We give a new mechanism for generating very small, and almost degenerate,
neutrino masses, without resorting to the see-saw mechanism or unnatural small
Yukawa couplings. It requires the existence of at least 4 families with an
almost democratic structure for the Yukawa couplings. It is also proven that
this structure can account for large lepton mixings of the three light leptons.


title:
A critical phenomenological study of inclusive photon production in
  hadronic collisions

abstract:
  We discuss fixed target and ISR inclusive photon production and attempt a
comparison between theory and experiments. The dependence of the theoretical
predictions on the structure functions, and on the renormalization and
factorization scales is investigated. The main result of this study is that the
data cannot be simultaneously fitted with a single set of scales and structure
functions. On the other hand, there is no need for an additional intrinsic
$k_{_T}$ to force the agreement between QCD predictions and experiments, with
the possible exception of one data set. Since the data cover almost overlapping
kinematical ranges this raises the question of consistency among data sets. A
comparative discussion of some possible sources of experimental uncertainties
is sketched.


title: Lee-Friedrichs Model

abstract:
  A brief summary of the mathematical structure of the Lee-Friedrichs model is
given, including the natural extension of its Hamiltonian to a Gel'fand triple,
containing a generalized eigenstate for the complex pole. Contains references
to some physical applications and relativistic generalizations.


title: Of dips and structures

abstract:
  A detailed analysis of the existence of high energy secondary diffractive
dips and structures in the extrapolations of the fits to the data is given. The
existence of these dips and a fortiori their position is found to be rather
model-dependent: present in all eikonalized models including Pomeron, Odderon
and secondary Reggeons they disappear when an additional large- t term is added
(as sometimes advocated).


title: Approximate solution of the BFKL equation applicable at HERA

abstract:
  We suggest a formula interpolating between the known asymptotic regimes of
the BFKL equation as the approximate solution of that equation. The parameters
appearing in this interpolation are fitted to the data on deep inelastic
scattering in a wide range of the kinematical variables. Care is taken of the
large-$x$ domain as well, outside the HERA kinematical region. The boundaries
and the interface between various dynamical regimes are also studied.