title: On the Minimal Messenger Model

abstract:
  We study the Minimal Messenger Model, a minimal version of Gauge Mediated
Supersymmetry Breaking models. Boundary conditions equal to zero for trilinear
and bilinear soft parameters at the messenger scale make this model free from
the supersymmetric CP problem and extremely predictive. These boundary
conditions and the vicinity of the messenger scale to the electroweak one,
require a careful implementation of the mechanism of radiative breaking of
$SU(2)\times U(1)$. We assess the importance of considering the complete
one-loop effective potential and of including a set of logarithmic two-loop
corrections to the B parameter for the correct determination of the electroweak
minimum. We analyze the resulting low-energy spectrum and give predictions of
interest for future experimental searches.


title:
Interplay of Non-Relativistic and Relativistic Effects in Neutrino
  Oscillations

abstract:
  A theoretical structure that involves neutrino mass eigenstates at non
relativistic as well as relativistic energies is presented. Using this
framework, we find that if the particle X, with mass 33.9 MeV, of the KARMEN
collaboration anomaly is identified with the third neutrino mass eigenstate,
then the present limit of 23 MeV upper bound on the tau neutrino mass implies
|U_{\tau 3}| < 0.82.


title: The Running Gauge Coupling in the Exact Renormalization Group Approach

abstract:
  We discuss the perturbative running Yang-Mills coupling constant in the
Wilsonian exact renormalization group approach, and compare it to the running
coupling in the more conventional MS-bar scheme. The exact renormalization
group approach corresponds to a particular renormalization scheme, and we
relate explicitly the corresponding Lambda-parameters. The unambiguous
definition of an exact renormalization group scheme requires, however, the use
of a one-loop improved high energy effective action.


title: Theory of Inclusive B Decays

abstract:
  We present the theory of inclusive decays of hadrons containing a heavy quark
and discuss its most important applications to the decays of B mesons. We also
review the theoretical understanding of the hadronic parameters lambda_1 and
lambda_2 (or mu_pi^2 and mu_G^2) entering the heavy-quark expansion.


title:
Equivalence of renormalized covariant and light-front perturbation
  theory: I. Longitudinal divergences in the Yukawa model

abstract:
  Light-front perturbation theory has been proposed as an alternative to
covariant perturbation theory. Light-front perturbation theory is only
acceptable if it produces invariant S-matrix elements. Doubts have been raised
concerning the equivalence of light-front and covariant perturbation theory.
One of the obstacles to a rigorous proof of equivalence is the occurrence of
longitudinal divergences not present in covariant perturbation theory. We show
in the case of the Yukawa model of fermions interacting with scalar bosons at
the one-loop level how to deal with the longitudinal divergences. Invariant
S-matrix elements are obtained using our method.


title: Flavour Changing Neutral Current Processes in B Decays

abstract:
  We review the theory and experimental measurements in the flavour changing
neutral current (FCNC) processes involving B decays in the context of the
standard model (SM). The role of these processes in determining the weak mixing
matrix elements is stressed.


title: K+ to pi-mu+mu+ and doubly-charged Higgs

abstract:
  The rate for the lepton-number-violating decay K+ to pi- mu+mu+ is calculated
in a model which incorporates doubly-charged Higgs bosons. We find that for
reasonable values of the parameters the decay branching ratio may be as large
as 2E-16. Although this is a discouragingly small number, it is of the same
order of magnitude as the rate mediated by massive Majorana neutrinos.


title:
Chiral Symmetry Amplitudes in the S-Wave Isoscalar and Isovector
  Channels and the \sigma, f_0(980), a_0(980) Scalar Mesons

abstract:
  We use a nonperturbative approach which combines coupled channel Lippmann
Schwinger equations with meson-meson potentials provided by the lowest order
chiral Lagrangians. By means of one parameter, a cut off in the momentum of the
loop integrals, which results of the order of 1 GeV, we obtain singularities in
the S-wave amplitudes corresponding to the \sigma,f_0 and a_0 resonances. The
\pi\pi-->\pi\pi, \pi\pi-->K\bar{K} phase shifts and inelasticities in the T=0
scalar channel are well reproduced as well as the \pi^-\eta and K^-K^0 mass
distributions in the T=1 channel. Furthermore, the total and partial decay
widths of the f_0 and a_0 resonances are properly reproduced including also the
decay into the \gamma\gamma channel. The results seem to indicate that chiral
symmetry constraints at low energy and unitarity in coupled channels is the
basic information contained in the meson-meson interaction below \sqrt(s)=1.2
GeV.


title: Consequences of a U(2) Flavour Symmetry

abstract:
  While solving the supersymmetric flavour problem, a U(2) flavour symmetry
might be at the origin of the pattern of fermion masses and mixings. The
consequences of this hypothesis are spelled out concerning the parameters of
the CKM matrix and their observability in B- and K-physics. The relevance of
searching for lepton flavour violation and for the electric dipole moments of
the electron and the neutron is also emphasized.


title: tau-->eta(eta')2pi nu, 3pi nu and WZW anomaly

abstract:
  The effects of the anomalous contact terms are taken into account in tau to
eta(eta')2pi nu decay. tau to 3pi nu is computed. Theoretical result agrees
with data. It is the first time the anomalous vertex eta aa is tested. An a_{1}
resonance is predicted in the final state. The decay rate of tau to eta'3pi nu
is predicted.


title: Neutrino Magnetic Moment Behaviour in a Renormalizable Model

abstract:
  We have shown in hep-ph/9608266 that a neutrino magnetic moment form factor
$\mu_{\nu} (q^2)$ could be considerably amplified at low momentum transfer,$q^2
\leq m_N^2$, at the cost of introducing an extra light neutral fermion $N$ with
mass $m_N$ and nonzero magnetic moment. It was assumed that the magnetic moment
of $N$ would originate in a renormalizable way at a heavy scale $M$. While the
enhancement of the neutrino magnetic moment was unambiguous, we stressed that
in this effective Lagrangian approach an uncertainty persisted about the
behaviour of $\mu_{\nu} (q^2)$ in the interval $m_N^2 \ll q^2 \ll M^2$. This is
not unexpected in presence of a nonrenormalizable effective theory (a particle
with bare magnetic moment). We show in a simple renormalizable model for the
magnetic moment of particle $N$ how a 2 loop calculation solves the ambiguity.
In the domain $m_N^2 \ll q^2 \ll M^2$ we confirm the result obtained in
hep-ph/9608266 using a sharp cut-off. It is amusing that the correct results
are given, as expected, through dimensional regularization in the full theory,
but not in the effective lagrangian approach.


title: QCD estimate of the long-distance effect in $B \to K^* \gamma$

abstract:
  We suggest to use operator product expansion and QCD sum rule techniques to
estimate the long-distance contribution to the amplitude of the exclusive rare
decay $B\to K^* \gamma$. In contrast to a phenomenological description in terms
of $\psi$ resonances converting into a photon, the virtual charm quark loop
interacting with soft gluons is represented by a new quark-gluon-photon
operator. The matrix element of this operator is calculated in the same
approximation as the matrix element of the leading magnetic penguin operator.
The overall correction is found to be small, not more than about 5%.


title: Supersymmetry and Broken Symmetries at High Temperature

abstract:
  It is generally believed that internal symmetries are necessarily restored at
high temperature in supersymmetric theories. We provide simple and natural
counterexamples to this no-go theorem for systems having a net background
charge. We exemplify our findings on abelian models, for both cases of global
and local symmetries and discuss their possible implications.


title:
``Topcolor''; Invited talk presented at "Strongly Coupled Gauge
  Theories, 1996", Nagoya, Japan, Nov. 1996

abstract:
  We review a class of dynamical models in which top condensation occurs at the
weak scale, giving rise to the large top quark mass and other phenomena. This
typically requires a color embedding, $SU(3)_c \rightarrow SU(3)_1\times
SU(3)_2$. These models imply many signatures addressable in near term
experiments at colliders and in fixed target mode.


title:
Gauge Dependence of Lower Bounds on the Higgs Mass Derived from
  Electroweak Vacuum Stability Constraints

abstract:
  We examine the gauge dependence of lower bounds on the Higgs mass obtained
from the requirement that the electroweak vacuum be the global minimum of the
effective potential. We study a simple model, the spontaneously-broken Abelian
Higgs model coupled to a chiral quark doublet in a two-parameter gauge and
demonstrate that the lower bounds on the Higgs mass obtained in this model are
dependent on the choice of gauge parameters. We discuss the significance of
this result for calculations in the Standard Model.


title: Comment on nonperturbative effects in $B\to X_s\gamma$

abstract:
  Uncertainties in the theoretical prediction for the inclusive $B\to
X_s\gamma$ decay rate are discussed. We emphasize that there is no operator
product expansion for this process. Nonetheless, some nonperturbative effects
involving a virtual $c\bar c$ loop are calculable using the operator product
expansion. They give a contribution to the decay rate that involves the B meson
matrix element of an infinite tower of operators. The higher dimension
operators give effects that are only suppressed by powers of
$m_b\Lambda_{QCD}/m_c^2 \sim 0.6$, but come with small coefficients.


title: Field Theory for the Standard Model

abstract:
  We review the origin of the standard electroweak model and discuss in great
detail the on-shell renormalization scheme of the standard model as a field
theory. One-loop radiative corrections are calculated by the dimensional
regularization and the dominant higher-order corrections are also discussed. We
then show how well the standard model withstands the precision test against the
LEP and SLD data along with its prediction on the indirect bound of the Higgs
boson mass $m_H$. The uncertainty in $m_H$ and in $Z-$decay parameters due to
the experimental uncertainties in $m_t, M_W$ and QED and QCD couplings is also
discussed.


title:
Finite temperature effects on the neutrino decoupling in the early
  Universe

abstract:
  Leading finite temperature effects on the neutrino decoupling temperature in
the early Universe have been studied. We have incorporated modifications of the
dispersion relation and the phase space distribution due to the presence of
particles in the heat bath at temperature around MeV. Since both the expansion
rate of the Universe and the interaction rate of a neutrino are reduced by
finite temperature effects, it is necessary to calculate thermal corrections as
precisely as possible in order to find the net effect on the neutrino
decoupling temperature. We have performed such a calculation by using the
finite temperature field theory. It has been shown that the finite temperature
effects increase the neutrino decoupling temperature by 4.4%, the largest
contribution coming from the modification of the phase space due to the thermal
bath.


title:
Manifestation of a strong electroweak sector with decoupling at hadronic
  colliders

abstract:
  We study the expected phenomenology at present (Tevatron) and future
(Tevatron Upgrade, LHC) hadronic colliders of a model describing a strong
electroweak symmetry breaking sector with both vector and axial vector strong
interacting bosons degenerate in mass. Due to decoupling, this model at low
energies is almost indistinguishable from the Standard Model, passing therefore
all low energy precision tests at LEPI. We will show that it gives quite
visible signals at forthcoming hadronic accelerators. The new charged vector
bosons can be detected more easily than the neutral ones.


title: Axion decay $a \to f \tilde f$ in a strong magnetic field

abstract:
  The axion decay into charged fermion-antifermion pair $a ~\to f ~\tilde f$ is
studied in external crossed and magnetic fields. The result we have obtained
can be of use to re-examine the lower limit on the axion mass in case of
possible existence of strong magnetic fields at the early Universe stage.


title: CP Violation, Mixing, and Quantum Mechanics

abstract:
  We discuss the quantum mechanics of B-factory experiments, and that of
neutral K or B decay. Predictions for the processes to be studied at the B
factories can be made through an approach based on amplitudes, rather than on
wave functions. This approach avoids the puzzles of the "collapse of the wave
function." In the treatment of the decay of a neutral K or B, the contributions
of the different mass eigenstate components of the decaying particle must be
evaluated at exactly the same spacetime point. Otherwise, the frequency
predicted for the oscillation of the decay rate may be incorrect.


title: Exclusive photo- and electroproduction of mesons in the GeV region

abstract:
  We consider the reactions gamma p --> M B, with M B being either K+ Lambda,
K+ Sigma0, or Pi n, within a diquark model which is based on perturbative QCD.
The model parameters and the quark-diquark distribution amplitudes of the
baryons are taken from previous investigations of electromagnetic baryon form
factors and Compton-scattering off protons. Reasonable agreement with the few
existing photoproduction data at large momentum transfer is found for meson
distribution amplitudes compatible with the asymptotic one (proportional to x
(1-x)). We present also first results for hard electroproduction of the K+
Lambda final state. Our predictions exhibit some characteristic features which
could easily be tested in forthcoming electroproduction experiments.


title: Does Neutrino Really Exist ?

abstract:
  An analysis of known experiments on direct and indirect detection of the
electron-type neutrino and antineutrino has been made. The analysis based on a
new hypothesis that the observed physical space is formed from a finite set of
byuons, "one-dimensional vectorial objects". It is shown in the article that
the hypothesis for existence of neutrinos advanced by Pauli on the basis of an
analysis of the conservation laws, is not unquestionable since the fulfillment
of these laws may be secured by the physical space itself (physical vacuum)
being the lowest energy state of a discrete oscillating system originating in
the course of byuon interaction. This effect is analogous to that of
M\"ossbauer. The direct experiments on detecting neutrinos are explained from
the existence of a new information channel due to the uncertainty interval for
coordinate of the four-contact byuon interaction forming the interior geometry
of elementary particles and their properties. Given are also the results of an
experiment on observation of cyclic variations of the $\beta$-decay rate, which
confirm the existence of said new information channel.


title: Higgs Physics: An Historical Perspective

abstract:
  ``Weakly-coupled'' and ``strongly-coupled'' models of electroweak symmetry
breaking are introduced by analogy with the Fermi theory of the weak
interaction and the low-energy interaction of pions, respectively. The
implications of these two classes of models for colliders beyond the LHC and
NLC are discussed.


title:
The Vacuum Polarization Function to O(alpha^2) Accuracy Near Threshold
  and Darwin Corrections

abstract:
  The QED vacuum polarization function is calculated to O(alpha^2)
(next-to-leading order) accuracy in the threshold regime by using the concept
of effective field theories to resum diagrams with the instantaneous Coulomb
exchange of longitudinally polarized photons. It is shown that the O(alpha^2)
contributions are of order alpha^2 in size rather than alpha^2/Pi^2. The vacuum
polarization contributions to the O(alpha^6) hyperfine splitting of the
positronium ground state are recalculated and differences with an older
calculation are pointed out. The results are used to determine O(C_F^2
alpha_s^2) (next-to-next-to-leading order) Darwin corrections to heavy
quark-antiquark bound state l=0 wave functions at the origin and to the heavy
quark-antiquark production cross section in e^+e^- collisions in the threshold
region. The absolute value of the corrections amounts to 10%-20% and 17%-34% in
the modulus squared of the ground state wave functions at the origin for the
$b\bar b$ and $c\bar c$ systems, respectively. In the case of the $t\bar t$
production cross section in the threshold region the absolute value of the
corrections is between 2% and 6% around the 1S peak and between 1% and 2% for
higher energies. A critical comment on recent QCD sum rule calculations for the
$\Upsilon$ system is made.


title: Existence of sigma meson in pi-pi scattering

abstract:
  In this talk I summarize a recently proposed mechanism to understand pi pi
scattering to 1 GeV. The model is motivated by the 1/Nc expansion to QCD, and
includes a current algebra contact term and resonant pole exchanges. Chiral
symmetry plays an important role in restricting the form of the interactions.
The existence of a broad low energy scalar (sigma) is indicated.


title: A Model with Anomalous U(1) Induced Supersymmetry Breaking

abstract:
  A model based on an anomalous Abelian symmetry $U(1)_1\times U(1)_2$ is
presented. This symmetry is responsible for both supersymmetry breaking and
fermion mass generation. Quark and squark mass matrices are aligned to prevent
large flavor-changing neutral current and CP-violation.


title: Precision W-boson and top-quark mass determinations at a muon collider

abstract:
  Precise determinations of the masses of the $W$ boson and of the top quark
could stringently test the radiative structure of the Standard Model (SM) or
provide evidence for new physics. We analyze the excellent prospects at a muon
collider for measuring $M_W$ and $m_t$ in the $W^+W^-$ and $t\bar t$ threshold
regions. With an integrated luminosity of 10 (100) fb$^{-1}$, the $W$-boson
mass could be measured to a precision of 20 (6) MeV, and the top-quark mass to
a precision of 200 (70) MeV, provided that theoretical and experimental
systematics are understood. A measurement of $\Delta m_t=200$ MeV for fixed
$M_W$ would constrain a 100 GeV SM Higgs mass within about $\pm 2$ GeV, while
$\Delta M_W=6$ MeV for fixed $m_t$ would constrain $m_h$ to about $\pm 10$ GeV.


title:
Multiplicity distributions in e+e- annihilation into hadrons and the
  extended modified negative binomial

abstract:
  It is shown that simple extension of the modified negative binomial
distribution describes negatively charged particle multiplicity distributions
in e+e- annihilation, measured in the whole phase space, as well as the
modified negative binomial.


title:
Fine-Tuning Problem in a Left-Right Symmetric Model and Sogami's
  Generalized Covariant Derivative Method

abstract:
  We study Sogami's generalized covariant derivative method for a $SU(2)_{L}
\times SU(2)_{R} \times U(1)_{B-L} \times SU(3)_{c}$ model that contains
bi-doublet and triplet Higgs bosons. In particular, a detailed study is made on
the minimization conditions of the Higgs potential. It is known that a
minimization condition and certain phenomenology for a extra gauge boson mass
derive a restriction on potential parameters, which requires fine-tuning. We
show that the restriction can be reduced to a condition of Yukawa coupling
constants giving a heavy mass of the right-handed tau neutrino in our model. We
also discuss the consistency among parameter restrictions of our model by
taking phenomenology of the Higgs boson masses into account.


title: Spontaneous CP violation and the B system

abstract:
  We investigate effects of spontaneous breakdown of CP in
$B^0_{d,s}-\overline{B^0}_{d,s}$ systems in left-right symmetric models.
Assuming that the left-right contribution to the $B^0-\overline{B^0}$ matrix
element $M_{12}$ can be at most equal to the standard model one we obtain a new
lower bound, $M_H\gsim 12$ TeV, on the flavour changing Higgs boson mass. Most
importantly, the convention independent parameter $Re(\overline{\epsilon}_B),$
which measures the amount of $\Delta B=2$ CP violation, can be enhanced by a
factor of four or more for $B^0_d$ and almost by two orders of magnitude for
$B^0_s$ systems when compared with the Standard Model predictions. Therefore,
interesting possibilities to observe indirect CP violation in the $B$ system
are open in the planned facilities.


title:
Dimensional structural constants from chiral and conformal bosonization
  of QCD

abstract:
  We derive the dimensional non-perturbative part of the QCD effective action
for scalar and pseudoscalar meson fields by means of chiral and conformal
bosonization. The related structural coupling constants L_5 and L_8 of the
chiral lagrangian are estimated using general relations which are valid in a
variety of chiral bosonization models without explicit reference to model
parameters. The asymptotics for large scalar fields in QCD is elaborated, and
model-independent constraints on dimensional coupling constants of the
effective meson lagrangian are evaluated. We determine also the interaction
between scalar quarkonium and the gluon density and obtain the scalar
glueball-quarkonium potential.


title: Scalar glueball: analysis of the (IJ^{PC}=00^{++})-wave

abstract:
  Basing on the previously performed K-matrix analysis of experimental data, we
investigate, in the framework of the propagator matrix (D-matrix) technique,
the 1100-1900 MeV mass region, where overlapping resonances $f_0(1300)$,
$f_0(1500)$, $f_0(1530^{+90}_{-250})$, and $f_0(1780)$ are located. Necessary
elements of the D-matrix technique are developed. The D-matrix analysis
confirms previous K-matrix results: in the region 900-1900 MeV five
scalar/isoscalar states are located. Four of them are members of the two $q\bar
q$-nonets, while one state is an extra for the $q\bar q$ systematics, being a
good candidate for the lightest scalar glueball. The D-matrix analysis shows
that this extra state, a candidate for the lightest scalar glueball, is
dispersed, due to a mixing with $q\bar q$- states, over three resonances:
$f_0(1300)$, $f_0(1500)$, and $f_0(1530^{+90}_{-250})$. The broad resonance
$f_0(1530^+{90}_{-250})$ is a descendant of the lightest glueball carrying
about 50% of the gluonium component, the rest of the gluonium is shared between
$f_0(1300)$ and $f_0(1500)$.


title: Why the SU(\infty) phase transition might be of second order

abstract:
  Based upon what is known about the phase transition(s) of an SU(3) gauge
theory, we argue that in a SU(N_c) gauge theory without quarks, at nonzero
temperature the deconfining phase transition is of second order when N_c \geq
4.


title:
Perturbative Corrections to a Sum Rule for the Heavy Quark Kinetic
  Energy

abstract:
  We calculate the perturbative corrections to order \alpha_s^2\beta_0 to the
sum rule derived from the second moment of the time-ordered product of b \to c
currents near zero recoil. This sum rule yields a bound on \lambda_1, the
expectation value of the b quark kinetic energy operator inside the B meson.
The perturbative corrections significantly weaken the bound relative to the
tree level result, yielding \lambda_1 < -0.15 GeV^2.


title: Supergravity corrections to $(g-2)_l$ in differential renormalization

abstract:
  The method of differential renormalization is extended to the calculation of
the one-loop graviton and gravitino corrections to $(g-2)_l$ in unbroken
supergravity. Rewriting the singular contributions of all the diagrams in terms
of only one singular function, U(1) gauge invariance and supersymmetry are
preserved. We compare this calculation with previous ones which made use of
momentum space regularization (renormalization) methods.


title:
Earth regeneration effect in solar neutrino oscillations: an analytic
  approach

abstract:
  We present a simple and accurate method for computing analytically the
regeneration probability of solar neutrinos in the Earth. We apply this method
to the calculation of several solar model independent quantities than can be
measured by the SuperKamiokande and Sudbury Neutrino Observatory experiments.


title: Contact interactions in the four-fermion processes at LEP2 and HERA

abstract:
  We consider the possibility of experimental observation of flavor-diagonal
and helicity conserving contact terms in the four fermion reactions e^+ e^- ->
e^+ e^- \mu^+ \mu^- and e^- q -> e^- \mu^+ \mu^- q at LEP2 and HERA.


title: Some implications of meson dominance in weak interactions

abstract:
  The hypothesis is scrutinized that the weak interaction of hadronic systems
at low energies is dominated by the coupling of the pseudoscalar, vector, and
axial-vector mesons to the weak gauge bosons. The strength of the weak coupling
of the rho(770) meson is uniquely determined by vector-meson dominance in
electromagnetic interactions; flavor and chiral symmetry breaking effects
modify the coupling of other vector mesons and axial-vector mesons. Many decay
rates are calculated and compared to experimental data and partly to
predictions of other models. A parameter-free description of the decay K^+ -->
pi^+ e^+e^- is obtained. Predictions for several not yet observed decay rates
and reaction cross sections are presented. The relation between the conserved
vector current hypothesis and meson dominance is clarified. Phenomenological
success of the meson dominance suggests that in some calculations based on the
standard model the weak quark-antiquark annihilation and creation diagrams may
be more important than anticipated so far. The processes are identified where
the meson dominance fails, implying that they are governed, on the quark level,
by some other standard model diagrams.


title: Final State Interactions in Bose-Einstein Correlations

abstract:
  We are presenting here the new formulae for Bose-Einstein correlations (BEC)
which contain effects of final state interactions (FSI) of both strong (in
$s$-wave) and electromagnetic origin. We demonstrate the importance of FSI in
BEC by analysing data for $e^+e^-$ annihilation and for heavy collisions. The
inclusion of FSI results in the practical elimination (at least in $e^+e^-$
data) of the so called degree of coherence parameter $\lambda$ (which becomes
equal unity) and the long range parameter $\gamma$ (which is now equal zero).


title:
Quasiscaling in the analysis of the yield ratio $\pi^-/\pi^+$:
  Mathematical structure and estimation of source size

abstract:
  Recently we have found that integral of the squared Coulomb wave function
describing systemcomposed of charged pion and central charged fragment
$Z_{eff}$ protons, $|\psi_r(r)|^2$, times pion source function $\rho(r)$ (of
the size $\beta$), $\intdr |\psi_r(r)|^2 \rho(r)$, shows a quasiscaling
behavior. This is approximately invariant under the following transformation:
$(\beta,Z_{eff}) \to (\lambda\beta,\lambda Z_{eff})$; $\lambda >0$. We called
such behavior $\beta-Z_{eff}$ quasiscaling. We examine this quasiscaling
behavior in detail. In particular we provide a semi-analytical examination of
this behavior and confirm it for the exponential pionic source functions in
addition to the Gaussian ones and for the production of K mesons as well. When
combined with the results of the HBT, a result of the yield ratio allows us to
estimate the size of the central charged fragment (CCF) to be $125\le
Z_{eff}\le 150$ for Pb+Pb collisions at energy 158 GeV/nucleon. From our
estimation, the baryon number density $0.024 \le n_{B}\le0.036$ [1/fm^3] is
obtained.


title: Wavelet Analyses of High Multiplicity Events

abstract:
  Pseudo-rapidity distributions of high multiplicity JACEE events ( Ca-C,
Si-AgBr and G27) and Texas Lone Star (TLS) event are analysed by the wavelet
transform method. Using the Daubechies' waveltes, $D_4, D_6, D_8,$ and $ D_{10}
$, wavelet spectra of those events are calculated. Two JACEE events are
compared with the simulation calculations. We discuss how to distinguish
prominent peak from apparent peaks. The wavelet spectrum of Ca-C event seems to
resemble that simulated with the Poisson random number distributions. The
wavelet spectrum of TLS event shows an oscillatory behavior. It is found that
the wavelet spectra of JACEE G27 event are different from those of Arizona
group.


title:
Single-quark spin asymmetries in e+ e- ---> t tbar and anomalous gluon
  couplings

abstract:
  The effect of anomalous chromoelectric couplings of the gluon to the top
quark are considered in e+ e- --> t tbar. The total cross section, as well as t
and tbar polarizations are calculated to order alpha_s in the presence of the
anomalous couplings. One of the two linear combinations of t and tbar
polarizations is CP even, while the other is CP odd. Limits that could be
obtained at a future linear collider on CP-odd combinations of anomalous
couplings are determined.


title: New Supersymmetric Contributions to $t->cV$

abstract:
  We calculate the electroweak-like one-loop supersymmetric contributions to
the rare and flavor-violating decay of the top quark into a charm quark and a
gauge boson: $t->c V$, with $V=\gamma,Z,g$. We consider loops of both charginos
and down-like squarks (where we identify and correct an error in the
literature) and neutralinos and up-like squarks (which have not been calculated
before). We also account for left-right and generational squark mixing. Our
numerical results indicate that supersymmetric contributions to $t->cV$ can be
upto 5 orders of magnitude larger than their Standard Model counterparts.
However, they still fall short of the sensitivity expected at the
next-generation top-quark factories.


title: Negative Parity Baryons in the QCD Sum Rule

abstract:
  Masses and couplings of the negative parity excited baryons are studied in
the QCD sum rule. Separation of the negative-parity spectrum is proposed and is
applied to the flavor octet and singlet baryons. We find that the quark
condensate is responsible for the mass splitting of the ground and the
negative-parity excited states. This is expected from the chiral symmetry and
supports the idea that the negative-parity baryon forms a parity doublet with
the ground state. The meson-baryon coupling constants are also computed for the
excited states in the QCD sum rule. It is found that the \pi NN^* coupling
vanishes in the chiral limit.


title:
Gluon polarization in transversely polarized nucleons and jet spin
  asymmetries at RHIC

abstract:
  We derive the analog of the Wandzura-Wilczek relation for the light-cone
distributions of polarized gluons in a transversely polarized nucleon. The
short distance cross-section is entirely due to the intrinsic transverse
momenta of gluon in the nucleon, in complete analogy to the quark case.
Numerical estimate for the double spin transverse asymmetries at RHIC are
presented.


title:
Penguin corrections and strong phases in a time-dependent analysis of
  $B^0_{d} \to \pi^+ \pi^-$

abstract:
  From a time-dependent analysis of the decay $B^0_{d} \to \pi^+ \pi^-$ and
using a model-dependent $A_P/A_T$ ratio of the penguin-to-tree amplitudes
contributing to the decay, both the weak phase $\alpha$ and the strong phase
shift difference $\delta$ can be extracted from the data. The value of the weak
phase $\beta$, expected to be measured from the decay $B^0_{d} \to J/\psi K_S$,
is used to parameterize the value of $A_P/A_T$ and the corresponding penguin
correction to the observed asymmetry in $B^0_{d} \to \pi^+ \pi^-$.


title:
Scale dependence of the chiral-odd twist-3 distributions $h_L(x)$ and
  $e(x)$

abstract:
  We evaluate the complete leading-order evolution kernels for the chiral-odd
twist-3 distributions $e(x)$ and $\widetilde h_L(x)$ of the nucleon. We
establish the connection between the evolution equations in light-cone position
and light-cone fraction representations, which makes a correspondence between
the non-local string operator product expansion and the QCD-inspired parton
model. The compact expression obtained for the local anomalous dimension matrix
coincides with previous calculations. In the multicolour QCD as well as in the
large-$x$ limit the twist-3 distributions obey simple DGLAP equations.
Combining these two limits, we propose improved DGLAP equations and compare
them numerically with the solutions of the exact evolution equations.


title:
Higgs Boson Mass Bounds in the Standard and Minimal Supersymmetric
  Standard Model with Four Generations

abstract:
  We study the question of distinguishability of the Higgs sector between the
standard model with four generations(SM4) and the minimal supersymmetric
standard model with four generations (MSSM4). We find that a gap exists between
the SM4 and MSSM4 Higgs boson masses for a range of the fourth generation
fermion mass considered in the analysis at a fixed top quark mass. We also
compare the Higgs boson mass bounds in these models with those in the standard
and the minimal supersymmetric standard models.


title:
Evolution of twist-3 fragmentation functions in multicolour QCD and the
  Gribov-Lipatov reciprocity

abstract:
  It is shown that twist-3 fragmentation functions in the large-$N_c$ limit of
QCD obey the DGLAP evolution equations. The anomalous dimensions are found
explicitly. The Gribov-Lipatov reciprocity is violated at the twist-3 level in
the leading logarithmic approximation.


title: Indirect effects of new resonances at future linear colliders

abstract:
  In this paper we consider a general $SU(2)_L\otimes SU(2)_R$ invariant
Lagrangian describing scalar, vector and axial-vector resonances. By expanding
the WW and the ZZ scattering amplitude up to the fourth order in the external
momenta we can compare the parameters of our Lagrangian with the ones used in
the effective chiral Lagrangian formalism. In the last approach there has been
a recent study of the fusion processes at future e^+e^- colliders at energies
above 1 TeV. We use these results to put bounds on the parameter space of our
model and to show that for the case of vector resonances the bounds obtained
from the annihilation channel in fermion pairs are by far more restrictive,
already at energies of the order of 500 GeV.


title: Re-examination of long distance effects in $b\to sl^+l^-$

abstract:
  We re-analyse the long distance contributions to the process $b \to s l^+
l^-$. Full $q^2$-behavior of the vector meson dominance amplitude is used
together with the effect of Terasaki suppression, and comparisons with the
previous results are given. We show that the interference between short- and
long- distance contributions makes it difficult to extract the short distance
information from the dominant long distance background, either in the dilepton
invariant mass distribution or in the single lepton energy spectrum.


title:
Horizontal, Anomalous U(1) Symmetry for the More Minimal Supersymmetric
  Standard Model

abstract:
  We construct explicit examples with a horizontal, ``anomalous'' $U(1)$ gauge
group, which, in a supersymmetric extension of the standard model, reproduce
qualitative features of the fermion spectrum and CKM matrix, and suppress FCNC
and proton decay rates without the imposition of global symmetries. We review
the motivation for such ``more'' minimal supersymmetric standard models and
their predictions for the sparticle spectrum. There is a mass hierarchy in the
scalar sector which is the inverse of the fermion mass hierarchy. We show in
detail why DeltaS = 2 FCNC are suppressed when compared with naive estimates
for nondegenerate squarks.


title: N=1 Supersymmetric Cosmic Strings

abstract:
  We investigate the microphysics of supersymmetric cosmic strings. In
particular we focus on the vortices admitted by N=1 supersymmetric abelian
Higgs models. We find the vortex solutions and demonstrate that the two
simplest supersymmetric cosmic string models admit fermionic superconductivity.
Further, by using supersymmetry transformations, we show how to solve for the
fermion zero modes giving rise to string superconductivity in terms of the
background string fields.


title:
A Study of the Day - Night Effect for the Super - Kamiokande Detector:
  I. Time Averaged Solar Neutrino Survival Probability

abstract:
  This is the first of two articles aimed at providing comprehensive
predictions for the day-night (D-N) effect for the Super-Kamiokande detector in
the case of the MSW $\nu_e \to \numt$ transition solution of the solar neutrino
problem. The one-year averaged probability of survival of the solar $\nue$
crossing the Earth mantle, the core, the inner 2/3 of the core, and the (core +
mantle) is calculated with high precision (better than 1%) using the elliptical
orbit approximation (EOA) to describe the Earth motion around the Sun. Results
for the survival probability in the indicated cases are obtained for a large
set of values of the MSW transition parameters $\Delta m^2$ and
$sin^22\theta_{V}$ from the ``conservative'' regions of the MSW solution,
derived by taking into account possible relatively large uncertainties in the
values of the $^{8}$B and $^{7}$Be neutrino fluxes. Our results show that the
one-year averaged D-N asymmetry in the $\nu_e$ survival probability for
neutrinos crossing the Earth core can be, in the case of $sin^22 \theta_{V}
\leq 0.13$, larger than the asymmetry in the probability for (only mantle
crossing + core crossing) neutrinos by a factor of up to six. The enhancement
is larger in the case of neutrinos crossing the inner 2/3 of the core. This
indicates that the Super-Kamiokande experiment might be able to test the
$sin^22\theta_{V} \leq 0.01$ region of the MSW solution of the solar neutrino
problem by performing selective D-N asymmetry measurements.


title: How pi0 -> gamma gamma changes with temperature

abstract:
  At zero temperature, in the chiral limit the amplitude for pi0 to decay into
two photons is directly related to the coefficient of the axial anomaly. At any
nonzero temperature, this direct relationship is lost: while the coefficient of
the axial anomaly is independent of temperature, in a thermal bath the
anomalous Ward identities do not uniquely constrain the amplitude for pi0 ->
gamma gamma. Explicit calculation shows that to lowest order about zero
temperature, this amplitude decreases.


title: Nucleon spin-flavor structure in SU(3) breaking chiral quark model

abstract:
  The SU(3) symmetric chiral quark model, which describes interactions between
quarks, gluons and the Goldstone bosons, explains reasonably well many aspects
of the flavor and spin structure of the proton, except for the values of
$f_3/f_8$ and $\Delta_3/\Delta_8$. Introducing the SU(3)-breaking effect
suggested by the mass difference between the strange and nonstrange quarks, we
find that this discrepancy can be removed and better overall agreement
obtained.


title:
$W\gamma\gamma$ Production at the Fermilab Tevatron Collider: Gauge
  Invariance and Radiation Amplitude Zero

abstract:
  The electroweak process $p\bar p \to \ell^\pm\nu\gamma\gamma$ is calculated
at tree level, including finite W width effects. In order to obtain a gauge
invariant amplitude, the imaginary parts of $WW\gamma$ triangle graphs and
$WW\gamma\gamma$ box diagrams have to be included, in addition to resumming the
imaginary contributions to the W polarization. We demonstrate the existence of
a radiation amplitude zero in $p\bar p \to W^\pm \gamma\gamma \to
\ell^\pm\nu\gamma\gamma$, and discuss how it may be observed in correlations of
the $\gamma\gamma$ and lepton rapidities at the Fermilab Tevatron.


title: Dynamics and Phenomenology of Charmonium Production off Nuclei

abstract:
  Nuclear suppression of charmonium production in proton-nucleus interactions
is poorly understood, what restrains our attempts to single out unusual effects
in heavy ion collisions. We develop a phenomenological approach, based on the
light-cone dynamics of charmonium production, which has much in common with
deep-inelastic scattering and Drell-Yan lepton pair production. The key
observation is the existence of a soft mechanism of heavy flavour production,
which scales in the quark mass and dominates shadowing corrections and
diffraction. It naturally explains the surprisingly strong nuclear suppression
of J/Psi at large Feynman-x_F. The low-x_F region is subject to a complicated
interplay of hard and soft mechanisms. With evaluated parameters we nicely
describe available data on charmonium production in proton-nucleus collisions.
Using these results we predict a new process, diffractive production of
charmonium on a nucleon target, which fraction in the total production rate of
charmonium is evaluated at 12%.


title: Spectroscopy of Heavy Mesons Expanded in 1/m_Q

abstract:
  Operating just once with the naive Foldy-Wouthuysen-Tani transformation on
the relativistic Fermi-Yang equation for $Q\bar q$ bound states described by
the semi-relativistic Hamiltonian which includes Coulomb-like as well as
confining scalar potentials, we have calculated heavy meson mass spectra of D
and B together with higher spin states. Based on the formulation recently
proposed, their masses and wave functions are expanded up to the second order
in $1/m_Q$ with a heavy quark mass $m_Q$ and the lowest order equation is
examined carefully to obtain a complete set of eigenfunctions for the
Schr\"odinger equation. Heavy quark effective theory parameters, $\bar\Lambda$,
$\lambda_1$, and $\lambda_2$, are also determined at the first and second order
in $1/m_Q$.


title: Flavor Asymmetry of Antiquark Distributions in the Nucleon

abstract:
  1. Introduction
  2. Possible violation of the Gottfried sum rule
  2.1 Gottfried sum rule 2.2 Early experimental results 2.3 NMC finding and
recent progress 2.4 Small $x$ contribution 2.5 Nuclear correction: shadowing in
the deuteron 2.6 Parametrization of antiquark distributions
  3 Expectations in perturbative QCD
  3.1 Operator product expansion 3.2 Perturbative correction to the Gottfried
sum
  4 Theoretical ideas for the sum-rule violation
  4.1 Lattice QCD 4.2 Pauli exclusion principle 4.3 Mesonic models 4.3.1
Meson-cloud contribution 4.3.2 Chiral models 4.3.3 Anomalous $Q^2$ evolution
4.4 Diquark model 4.5 Isospin symmetry violation 4.6 Flavor asymmetry ubar-dbar
in nuclei 4.7 Relation to nucleon spin 4.8 Comment on effects of quark mass and
transverse motion
  5 Finding the flavor asymmetry ubar-dbar in various processes
  5.1 Drell-Yan process 5.1.1 Fermilab-E866 results 5.2 W and Z production 5.3
Quarkonium production at large $x_{_F}$ 5.4 Charged hadron production 5.5
Neutrino scattering 5.6 Experiments to find isospin symmetry violation
  6 Related topics on antiquark distributions
  7 Summary and outlook


title: Semilocal string formation in two dimensions

abstract:
  We present a toy model for the investigation of the formation of semilocal
strings, where a planar symmetry is employed to reduce the system to two
dimensions. We approximate the symmetry breaking using an extension of the
Vachaspati-Vilenkin algorithm, where we throw down random phases for the scalar
fields and then find the gauge field configuration which minimizes gradient
energy in this fixed scalar background. We show this procedure reproduces the
standard estimate for the formation rate of cosmic strings. For semilocal
strings the configurations generated by this method are ambiguous, and we
numerically evolve the configurations forward in time to identify which regions
form strings. We find a significant rate of formation, depending on the ratio
of couplings $\beta$. For low $\beta$ the formation rate is about one quarter
that of cosmic strings; this falls as $\beta$ is increased and above $\beta =
1$, where the string solution is dynamically unstable, no semilocal strings
form. We show the results are robust by examining different initial conditions
where, as expected in a thermal environment, the initial scalar field need not
be on the vacuum. We discuss implications for the three-dimensional case.


title: Confinement in the Coulomb Gauge Model

abstract:
  The Coulomb gauge model of QCD is studied with the introduction of a
confining potential into the scalar part of the vector potential. Using a Green
function formalism, we derive the self-energy for this model, which has both
scalar and vector parts, $\Sigma^S(p)$ and $\Sigma^V(p)$. A rotation of these
variables leads to the so-called gap and energy equations. We then analyse the
divergence structure of these equations. As this depends explicitly on the form
of potential, we give as examples both the linear plus Coulomb and
quadratically confining potentials. The nature of the confining single particle
Green function is investigated, and shown to be divergent due to the infrared
singularities caused by the confining potential. Solutions to the gap equation
for the simpler case of quadratic confinement are found both semi-analytically
and numerically. At finite temperatures, the coupled set of equations are
solved numerically in two decoupling approximations. Although chiral symmetry
is found only to be exactly restored as $T\to\infty$, the chiral condensate
displays a steep drop over a somewhat small temperature range.


title: Lambda_b polarization in the Z boson decays

abstract:
  In the framework of the perturbative QCD and the diquark model of baryons we
have obtained the fragmentation functions for heavy quark that split into
polarized Lambda_b baryons. We predict the longitudinal polarization asymmetry
for the prompt Lambda_b produced in electron-positron annihilation at the Z
resonance and estimate the spin-1/2 and spin-3/2 beauty baryon production rate.


title: The Future of Particle Physics as a Natural Science

abstract:
  In the first part of the talk, I give a low-resolution overview of the
current state of particle physics - the triumph of the Standard Model and its
discontents. I review and re-endorse the remarkably direct and (to me)
compelling argument that existing data, properly interpreted, point toward a
unified theory of fundamental particle interactions and toward low-energy
supersymmetry as the near-term future of high energy physics as a natural
science. I then attempt, as requested, some more `visionary' - i.e. even lower
resolution - comments about the farther future. In that spirit, I emphasize the
continuing importance of condensed matter physics as a source of inspiration
and potential application, in particular for expansion of symmetry concepts,
and of cosmology as a source of problems, applications, and perhaps ultimately
limitations.


title: Supernova Bounds on Resonant Active-Sterile Neutrino Conversions

abstract:
  We discuss the effects of resonant $\nu_e \to \nu_s$ and $\bar{\nu}_e \to
\bar{\nu}_s$ ($\nu_s$ is a sterile neutrino) conversions in the dense medium of
a supernova. In particular, we assume the sterile neutrino $\nu_s$ to be in the
hot dark matter few eV mass range. The implications of such a scenario for the
supernova shock re-heating, the detected $\bar\nu_e$ signal from SN1987A and
for the r-process nucleosynthesis hypothesis are analysed in some detail. The
resulting constraints on mixing and mass difference for the $\nu_e-\nu_s$
system are derived. There is also an allowed region in the neutrino parameter
space for which the r-process nucleosynthesis can be enhanced.


title: Diffractive Parton Distributions in the Semiclassical Approach

abstract:
  Recently, a semiclassical approach to diffraction has been proposed, which
treats the proton as a classical colour field. The present paper demonstrates
that this approach is consistent with the concept of diffractive parton
distributions. The diffractive quark and gluon distributions are expressed
through integrals of non-Abelian eikonal factors in the fundamental and adjoint
representation respectively. As a by-product, previously calculated diffractive
cross sections for processes with a final state gluon are rederived in a
simpler way.


title:
Two-loop Anomalous Dimensions of Heavy Baryon Currents in Heavy Quark
  Symmetry

abstract:
  This talk presents details of the calculation of two-loop corrections to
heavy baryon currents containing one heavy quark in leading order of the
$1/m_Q$-expansion, i.e. in the limit of Heavy Quark Symmetry (HQS). The
calculations lead to the determination of the anomalous dimension of these
currents. I also discuss problems with different $\gamma_5$-schemes and their
solution by the finite renormalization procedure.


title: B Decays and the Heavy-Quark Expansion

abstract:
  We review the theory and phenomenology of heavy-quark symmetry, exclusive
weak decays of B mesons, inclusive decay rates and lifetimes of b hadrons.


title: Screened Perturbation Theory

abstract:
  A new perturbative scheme is proposed for the evaluation of the free energy
density of field theories at finite temperature. The screened loop expansion
takes into account exactly the phenomenon of screening in thermal propagators.
The approach is tested in the N-component scalar field theory at 2-loop level
and also at 3-loop in the large N limit. The perturbative series generated by
the screened loop expansion shows much better numerical convergence than
previous expansions generated in powers of the quartic coupling.


title: Cosmic Texture from a Broken Global SU(3) Symmetry

abstract:
  We investigate the observable consequences of creating cosmic texture by
breaking a global SU(3) symmetry, rather than the SU(2) case which is generally
studied. To this end, we study the nonlinear sigma model for a totally broken
SU(3) symmetry, and develop a technique for numerically solving the classical
field equations. This technique is applied in a cosmological context: the
energy of the collapsing SU(3) texture field is used as a gravitational source
for the production of perturbations in the primordial fluids of the early
universe. From these calculations, we make predictions about the appearance of
the anisotropies in the cosmic microwave background radiation (CMBR) which
would be present if the large scale structure of the universe was
gravitationally seeded by the collapse of SU(3) textures.


title: SU(4) Preonic Interpretation of the HERA Positron-Jet Events

abstract:
  We show that our recent SU(4) generalized ``rishon'' composite model for
quarks and leptons, augmented either by the hypothesis of breaking of color
SU(3) to ``glow'' SO(3), or by the hypothesis of incomplete color
neutralization in very hard processes, leads to an interpretation of the HERA
positron-jet events as the production by color gluon exchange, followed by the
decay by color gluon emission, of the positron member of a heavy family partner
of the positron.


title: A Study of Off-Forward Parton Distributions

abstract:
  An extensive theoretical analysis of off-forward parton distributions (OFPDs)
is presented. The OFPDs and the form factors of the quark energy-momentum
tensor are estimated at a low-energy scale using a bag model. Relations among
the second moments of OFPDs, the form factors, and the fraction of the nucleon
spin carried by quarks are discussed.


title: Comment On Nonperturbative O(1/m_c^2) Corrections to B -> X_s gamma

abstract:
  We present an estimate of certain higher order corrections to the
contribution of the charm triangle loop in the inclusive B -> X_s gamma decay
rate, recently discussed by Voloshin. We find that these corrections are minute
and hence the result found by Voloshin, although small, is quite robust.


title: Top quark condensation

abstract:
  Top quark condensation, in particular the minimal framework where the neutral
Higgs scalar is (predominantly) an effective ${\bar t} t$ condensate of the
Standard Model, is reviewed. Computational approaches are compared and
similarities, differences and deficiencies pointed out. Extensions of the
minimal framework, including scenarios with two composite Higgs doublets,
additional neutrino condensates, and ${\bar t}t$ condensation arising from
four-fermion interactions with enlarged symmetries, are described. Possible
renormalizable models of underlying physics potentially responsible for the
condensation, including topcolor assisted technicolor frameworks, are
discussed. Phenomenological implications of top condensate models are outlined.
Outstanding theoretical issues and problems for future investigation are
pointed out. Progress in the field after this article was accepted has been
briefly covered in a Note added at the end.


title: Isospin Violation in tau -> 3 pi nu_tau

abstract:
  Isospin violating signals in the tau -> 3 pi nu_tau decay mode are discussed.
For the tau -> pi^- pi^- pi^+ nu_tau decay mode, isospin violation arises from
the vector current contribution in the tau -> omega pi nu_tau decay with the
subsequent isospin violating omega decay into pi^+ pi^-. We demonstrate that
such effects may be observed in presently available data through the
measurement of the interference effects of these vector current contributions
with the dominating axial vector current, i.e. through a measurement of the
structure functions W_F,W_G,W_H and W_I. In the case of the tau -> pi^0 pi^0
pi^- nu_tau decay mode, a vector current contribution is generated by eta pi
mixing in the decay chain tau -> eta rho nu_tau -> pi^0 pi^0 pi^- nu_tau. We
find that this effect is rather small, the magnitude of the associated
interference terms being too low for present statistics.


title:
\eta-\eta' -Glueball mixing from photon-meson transition form factors
  and decay ratio D_s --> \eta l \nu / \eta' l \nu

abstract:
  The background due to the direct diffractive dissociation of the photon into
the $\pi^+\pi^-$-pair to the "elastic" diffractive $\rho^0$-meson production in
electron-proton collisions is calculated. The amplitude for the background
process $\gamma p \to \pi^+ \pi^- p$ is proportional to the $\pi$-meson -
proton cross section. Therefore, describing the HERA data, we can estimate
$\sigma (\pi p)$ at energy $s_{\pi p}\sim (2 - 3) 10^{3} GeV^2$ that is
considerably higher the existing data. At large $Q^2$ the interference between
resonant and non-resonant $\pi^+ \pi^-$ production leads also to the more slow
increase of the $\sigma^L/\sigma^T$ ratio with the mass of the $2\pi$ (i.e.
$\rho^0$-meson) state.


title:
Order (1/m_Q) Corrections to Masses of Excited Heavy Mesons From QCD Sum
  Rules

abstract:
  The $O(1/m_Q)$ corrections to masses of excited heavy mesons are studied with
sum rules in the heavy quark effective theory. Numerical results for the matrix
elements of the heavy quark kinetic energy operator K and chromomagnetic
interaction operator S are obtained for the lowest excited doublets $(0^+,
1^+)$ and $(1^+, 2^+)$.


title: Charmonium Production at ELFE Energies

abstract:
  I discuss issues related to charmonium production, in view of physics
possibilities at a 15 ... 30 GeV continuous beam electron facility. High energy
photo- and hadroproduction of heavy quarkonia presents several challenges to
QCD models concerning cross sections, polarization and nuclear target
dependence. Theoretical approaches based on color evaporation as well as on
color singlet and color octet mechanisms have met with both successes and
failures, indicating that charmonium production is a sensitive probe of color
dynamics. Experiments close to charm kinematic threshold will be sensitive also
to target substructure since only unusual, compact target configurations
contribute. In particular, subthreshold production on nuclei should identify
nuclear hot spots of high energy density. At low energies, charmonium will form
inside the target nucleus, allowing a determination of c cbar bound state
interactions in nuclear matter.


title: Decays of W Bosons to Charginos and Neutralinos

abstract:
  The region of the supersymmetry parameter space, in which charginos decay
predominantly into sneutrinos and leptons: chi+ -> \tilde{\nu} + l+, is not
excluded experimentally for small mass differences between charginos and
sneutrinos. The decay sneutrinos are invisible in R-parity conserving theories
since they are either the lightest supersymmetric particles or they decay
primarily into the channel: neutrino + lightest neutralino. If the energy of
the decay leptons is so small that they escape detection, chargino events e+e-
-> chi+chi- in e+e- collisions remain invisible, eroding the excluded chargino
mass range at LEP. This region of the supersymmetry parameter space can partly
be covered by searching for single W events in e+e- -> W+W-$, with one W boson
decaying to leptons or quark jets, but the second W boson decaying to
(undetected) charginos and neutralinos.


title:
Complete Leading Order Analysis in Chiral Perturbation Theory of the
  Decays $K_L\to\gamma\gamma$ and $K_L\to\ell^+\el^-\gamma$

abstract:
  The decays $K_L \to \gamma\gamma$ and $K_L \to \ell^+ \ell^- \gamma$ are
studied at the leading order $p^6$ in Chiral Perturbation Theory. One-loop
contributions stemming from the odd intrinsic parity $|\Delta S| = 1$ effective
Lagrangian of order $p^4$ are included and shown to be of possible relevance.
They affect the decay $K_L \to \gamma\gamma$ adding to the usual pole terms a
piece free of counterterm uncertainties. In the case of the $K_L \to \ell^+
\ell^- \gamma$ decays the dependence of the form factor on the dilepton
invariant mass requires a counterterm. The form factor may receive a sizeable
contribution from chiral logarithms. Including considerations from the $K_L \to
\pi^+ \pi^- \gamma$ direct emission amplitude, we obtain two consistent
scenarios. In one scenario the long distance contributions from the one-loop
terms are important, while in the other they are marginal. In both cases the
counterterm is shown to be significant.


title: On the thermal mass shift of nucleons

abstract:
  The mass shift $\Delta m_N$ of a nucleon in the finite temperature pion gas
is calculated in the case of an arbitrary nucleon momentum. A general formula
is used which relates the in-medium mass shift $\Delta m(E)$ of a particle to
the real part of the forward scattering amplitude $Re f(E)$ of this particle on
constituents of the medium and its applicability domain is formulated. The mass
shift of the nucleon in thermal equilibrium with pion gas is also calculated.


title: D^* production from e^+e^- to ep collisions in NLO QCD

abstract:
  Fragmentation functions for D mesons, based on the convolution of a
perturbative part, related to the heavy quark perturbative showering, and a
non-perturbative model for its hadronization into the meson, are used to
describe D^* production in e^+e^- and ep collisions. The non-perturbative part
is determined by fitting the e^+e^- data taken by ARGUS and OPAL at 10.6 and
91.2 GeV respectively. When fitting with a non perturbative Peterson
fragmentation function and using next-to-leading evolution for the perturbative
part, we find an epsilon parameter sensibly different from the one commonly
used, which is instead found with a leading order fit. The use of this new
value is shown to increase considerably the cross section for D^* production at
HERA, suggesting a possible reconciliation between the next-to-leading order
theoretical predictions and the experimental data.


title:
Top and Higgs decays: looking for quantum SUSY signatures in hadron
  colliders

abstract:
  I present an updated discussion of the one-loop corrections to the standard
top quark decay, t-> W^+ b, and to the charged Higgs mode, t-> H^+ b, within
the framework of the MSSM. These higher order contributions to the top width
are compared with the direct top decays into 2 and 3 real SUSY particles. It
turns out that whereas the SUSY effects on t-> W^+ b add up to those from
standard QCD, they tend most likely to erase the conventional QCD corrections
to t-> H+ b. However, in the latter case the full (strong plus electroweak)
SUSY quantum effects are generally so large that the QCD corrections
effectively come out with the ``wrong sign''. A qualitatively distinct, and
quantitatively significant, ``quantum signature'' of that type might constitute
a most sought-after imprint of ``virtual'' Supersymmetry, which remains
sizeable enough even in the absence of any direct top decay into SUSY
particles. Similar considerations are made for the hadronic partial widths of
the Higgs bosons of the MSSM. While a first valuable test of these effects
could possibly be performed at the upgraded Tevatron, a more precise
verification would most probably be carried out in future experiments at the
LHC.


title: Gauge-Yukawa Unified Models

abstract:
  Gauge-Yukawa Unification (GYU) is obtained in GUTs by searching for
renormalization group invariant relations among gauge and Yukawa couplings
beyond the unification scale. Of particular interest are two supersymmetric
GUTs, the finite and the minimal SU(5) models. Both models provided us,among
others,with predictions of the top quark mass which so far have passed
successfully the tests of progressively more accurate measurements.


title: R-Parity Violation at HERA ?

abstract:
  We examine the possibility that the high-Q^2 events seen at HERA are due to
the production and decay of squarks of R-parity violating supersymmetry. The
relevant R-parity violating coupling(s) is identified and shown to lie between
0.03 and 0.26. Consequences of such a coupling at other experiments, such as
the LEP and Tevatron, are discussed.


title:
Resonant CP violation induced by particle mixing in transition
  amplitudes

abstract:
  We analyze CP violation in resonant transitions involving scalar as well as
fermionic intermediate states, using a gauge-invariant resummation approach
implemented by the pinch technique. We derive the necessary conditions for
resonantly enhanced CP violation induced by particle mixing, by paying special
attention to CPT invariance, and apply the results of our analysis to two
representative new-physics scenarios: (i) the indirect mixing of a CP-even
Higgs scalar with a CP-odd Higgs particle in two-Higgs doublet models and (ii)
the CP-asymmetric mixing between the top quark and a new heavy up-type quark,
$t'$, in mirror fermion models. Furthermore, we explicitly demonstrate the
equivalence of our scattering-amplitude formalism with that based on the
effective Hamiltonian and discuss the possibility of maximal CP violation in
the limiting case of two degenerate particles.


title: Muon capture by a proton in heavy baryon chiral perturbation theory

abstract:
  The matrix element for muon capture by a proton is calculated to O(p^3)
within heavy baryon chiral perturbation theory using the new O(p^3) Lagrangian
of Ecker and Mojzis. External nucleon fields are renormalized using the
appropriate definition of the wave function renormalization factor Z_N. Our
expression for Z_N differs somewhat from that found in existing literature, but
is the one which is consistent with the Lagrangian we use and the one which
ensures, within our approach, the nonrenormalization of the vector coupling as
required by the conserved vector current. Expressions for the standard muon
capture form factors are derived and compared to experimental data and we
determine three of the coefficients of the Ecker - Mojzis Lagrangian, namely,
b_7, b_{19}, and b_{23}.


title: Time-of-night variation of solar neutrinos

abstract:
  We investigate the time-of-night variation of solar neutrino rate which will
be of relevance to Super-Kamioka and Sudbury neutrino detectors in the
framework of oscillations among the three flavors. An analytical method of
computing the regeneration in the earth is presented. If day-night effect is
seen, we show how the study of the time-of-night variation will allow the
determination of the neutrino parameters.


title: Current-Carrying Zero Mode for the Nielsen-Olesen String

abstract:
  Zero modes of strings in the abelian Higgs model are analyzed. In spite of
the fact that the gauge symmetry is not broken in the string center, the
corresponding zero mode is shown to exist and to see it one has to analyze
carefully the dependence on transverse coordinates for the excitations. The
analysis of this kind is also important for the Witten model of superconducting
string. Unusual properties of the zero modes connected with the broken gauge
symmetry in the string background are investigated. One of the modes carries
the current quite similar to that in the Witten model and gives back reaction
to the string profile. It is claimed that the current in the string improves
stability of the electroweak string.


title:
Multiplicity and Transverse Energy Distributions Associated to Rare
  Events in Nucleus-Nucleus Collisions

abstract:
  We show that in high energy nucleus-nucleus collisions the transverse energy
or multiplicity distribution P_C, associated to the production of a rare,
unabsorbed event C, is universally related to the standard or minimum bias
distribution P by the equation $P_C(\nu)={\nu\over<\nu>}P(\nu)$, with $\sum
P(\nu)=1$ and $\nu\equiv E_T$ or n. Deviations from this formula are discussed,
in particular having in view the formation of the plasma of quarks and gluons.
This possibility can be distinguished from absortion or interaction of
comovers, looking at the curvature of the $J/\Psi$ over Drell-Yan pairs as a
function of E_T.


title:
Moment Analysis, Multiplicity Distributions and Correlations in High
  Energy Processes: Nucleus-Nucleus Collisions

abstract:
  Cumulant oscillations, or $H_q$ moment oscillations, appear if the KNO
multiparticle distribution decreases at large z, $z\equiv n/ <n>$, faster than
the exponential, $exp(-D z^\mu)$, with $\mu > 1$. In nucleus-nucleus
interactions this behaviour is related to the limitation in the average number
of elementary central collisions (or average number of strings centrally
produced), due to the finite number of nucleons involved. Colour deconfinement,
via percolating string fusion, will drastically decrease the fraction of
centrally produced strings and increase the cut-off parameter $\mu$: Moment
oscillations will be displaced to smaller q and the width of the KNO
distribution and forward-backward particle correlations will become smaller.


title: Non-perturbative aspects of (supersymmetric) gauge theories

abstract:
  At an elementary level, we present some non-perturbative aspects of
non-abelian gauge theories in four dimensional space-time. Some rigorous
results have been obtained in the framework of supersymmetric theories, and a
very rich physics related to the strong-coupling dynamics of gauge fields has
been discovered. Some of the new phenomena which appeared may play a
significant role in future phenomenological models. However, quantitative
computations in non-supersymmetric theories, like quantum chromodynamics, is
out of reach for the moment.


title:
Three-Neutrino Mixing and Combined Vacuum Oscillations and MSW
  Transitions of Solar Neutrinos

abstract:
  Assuming three flavour neutrino mixing takes place in vacuum, we investigate
the possibility that the solar nu_e take part in MSW transitions in the Sun due
to Delta m^2_{31} from 10^{-7} eV^2 to 10^{-4} eV^2, followed by long wave
length vacuum oscillations on the way to the Earth, triggered by Delta m^2_{21}
(or Delta m^2_{32}) from 10^{-12} eV^2 to 10^{-10} eV^2, Delta m^2_{31} and
Delta m^2_{21} (Delta m^2_{32}) being the corresponding neutrino mass squared
differences. The solar nu_e survival probability is shown to be described in
this case by a simple analytic expression. Depending on whether the vacuum
oscillations are due to Delta m^2_{21} or Delta m^2_{32} there are two very
different types of interplay between the MSW transitions and the vacuum
oscillations of the solar nu_e. Performing an analysis of the most recently
published solar neutrino data we have found several qualitatively new solutions
of the solar neutrino problem of the hybrid MSW transitions + vacuum
oscillations type. The solutions differ in the way the pp, 7Be and 8B neutrino
fluxes are affected by the transitions in the Sun and the oscillations in
vacuum. The specific features of the new solutions are discussed.


title:
The Nuclear Effect Induced by Additional Parton Evolution and
  Recombination in Nuclear Environment

abstract:
  The relationship between the parton transverse momentum and longitudinal
momentum, which is obtained by analysing the hadron tensor in the deep
inelastic scattering (DIS) process, indicates that the transverse size of
partons in a nucleon is sensitively affected by the effective nucleon mass. The
change in this transverse size gives rise to an Additional Parton Evolution
(APE) in the nuclear environment refer to the normal QCD parton evolution thus
resulting in new parton distributions. The self-consistent integral equations
for these new parton distributions are given. Having undergone the normal QCD
evolution and the additional evolution in the nuclear environment, the partons
with the small x participate in recombination and contribute to the nuclear
shadowing effect. The reasonably good descriptions of the nuclear effect of
structure functions, nuclear Drell-Yan ratios and nuclear gluon distributions
are presented. A quantitative comparison between the APE model and the
Q^2-rescaling model is made.


title:
The Effective Lagrangian of QED with a Magnetic Charge and Dyon Mass
  Bounds

abstract:
  The effective Lagrangian of QED coupled to dyons is calculated. The resulting
generalization of the Euler-Heisenberg Lagrangian contains non-linear P and T
noninvariant terms corresponding to the virtual pair creation of dyons. The
corresponding P and T violating part of the matrix element for light-by-light
scattering is considered. This effect induces an electric dipole moment for the
electron, of order M^{-2}, where M is the dyon mass. The current limit on the
electric dipole moment of the electron yields the lower dyon mass bound M > 1
TeV.


title: Thermal Effective Potential of the O(N) Linear sigma Model

abstract:
  The finite-temperature effective potential of the O(N) linear \sigma model is
studied, with emphasis on the implications for the investigation of hot hadron
dynamics. The contributions from all the ``bubble diagrams'' are fully taken
into account for arbitrary N; this also allows to address some long-standing
issues concerning the use of non-perturbative approaches in
(finite-temperature) field theory.


title: Instantons and the Chiral Phase Transition

abstract:
  We examine the role of instantons in the zero-temperature chiral phase
transition in an SU(N) gauge theory. For a range of N_f (the number of fermion
flavors) depending on N, the theory exhibits an infrared fixed point at
coupling $\alpha_*$. As N_f decreases, $\alpha_*$ increases, and it eventually
exceeds a critical value sufficient to trigger chiral symmetry breaking. For
the case N = 2, we estimate the critical values of N_f and $\alpha_*$ due to
instantons by numerically solving a gap equation with an instanton-generated
kernel. We find instanton effects of strength comparable to that of gluon
exchange.


title: Towards a Solution of the Cosmological Domain Walls Problem

abstract:
  We show that all kinds of biasing of cosmological phase transitions produce
qualitatively new type of domain wall networks. The biased networks consist of
compact, finite size, bag-like wall structures and exhibit a generic
instability. The surface of biased networks disappears exponentially fast after
a limited period of scaling. We argue that fluctuations of the background make
the network unstable even in the case of the ``symmetric on the average''
initial distribution. We observe that the variation in parameters of the
potential, like its hight, can influence the lifetime of the wall network,
contrary to the standard beliefs.


title:
Chiral Perturbation Theory Calculations For S-wave $\pi^0$ production In
  pp Collision

abstract:
  The total cross section for the pp --> pp $\pi^0$ reaction at energies close
to threshold is calculated within the frame of a chiral perturbation theory.
The tree and one loop diagrams up to chiral order D=2 contributions are taken
into account. The $L^{(0)}$ isoscalar-scalar part of t-channel two-pion
exchange loop diagrams enhances the production amplitude strongly. The
calculated cross section scale and energy dependence are very close to data.


title:
A lattice test of alternative interpretations of ``triviality'' in
  $(\lambda \Phi^4)_4$ theory

abstract:
  There are two physically different interpretations of ``triviality'' in
$(\lambda\Phi^4)_4$ theories. The conventional description predicts a
second-order phase transition and that the Higgs mass $m_h$ must vanish in the
continuum limit if $v$, the physical v.e.v, is held fixed. An alternative
interpretation, based on the effective potential obtained in
``triviality-compatible'' approximations (in which the shifted `Higgs' field
$h(x)\equiv \Phi(x)-<\Phi>$ is governed by an effective quadratic Hamiltonian)
predicts a phase transition that is very weakly first-order and that $m_h$ and
$v$ are both finite, cutoff-independent quantities. To test these two
alternatives, we have numerically computed the effective potential on the
lattice. Three different methods were used to determine the critical bare mass
for the chosen bare coupling value. All give excellent agreement with the
literature value. Two different methods for obtaining the effective potential
were used, as a control on the results. Our lattice data are fitted very well
by the predictions of the unconventional picture, but poorly by the
conventional picture.


title:
Coherent Description of D^{*+-} Production in e^+e^- and Low-Q^2 ep
  Collisions

abstract:
  We present new sets of fragmentation functions for D^{*+-} mesons, both at
leading and next-to-leading order. They are determined by fitting LEP1 data on
inclusive D^{*+-} production in e^+e^- annihilation. In one of the sets, we
take the charm-quark fragmentation function to be of the form proposed by
Peterson et al. and thus obtain updated values of the epsilon_c parameter and
the c -> D^{*+} branching ratio. The new fragmentation functions lead to an
excellent description of other e^+e^- data with centre-of-mass energies between
10 and 35 GeV. They also nicely agree with recent HERA data on inclusive
D^{*+-} photoproduction in ep collisions, which may be considered as a test of
the universality of the fragmentation into D^{*+-} mesons.


title: Electroweak baryogenesis and low energy supersymmetry

abstract:
  Electroweak baryogenesis is an interesting theoretical scenario, which
demands physics beyond the Standard Model at energy scales of the order of the
weak boson masses. It has been recently emphasized that, in the presence of
light stops, the electroweak phase transition can be strongly first order,
opening the window for electroweak baryogenesis in the MSSM. For the
realization of this scenario, the Higgs boson must be light, at the reach of
the LEP2 collider. In this article, we compute the baryon asymmetry assuming
the presence of non-trivial CP violating phases in the parameters associated
with the left-right stop mixing term and the Higgsino mass $\mu$. We conclude
that a phase $|\sin \phi_{\mu}| > 0.01$ and Higgsino and gaugino mass
parameters $|\mu| \simeq M_2$, and of the order of the electroweak scale, are
necessary in order to generate the observed baryon asymmetry.


title: Dynamical determination of the Supersymmetric Higgs mass

abstract:
  Considering the supersymmetric Higgs mass ($\mu$-parameter) as a dynamical
variable to be determined by minimizing the energy, we predict its value as a
function of the soft masses of the potential. We find that $\mu$ has a nonzero
value close to the weak scale. This scenario offers a simultaneous solution to
the doublet-triplet splitting problem and to the $\mu$-problem. We discuss its
viability in theories with gauge mediated supersymmetry breaking.


title: The analytic structure of heavy quark propagators

abstract:
  The renormalised quark Dyson-Schwinger equation is studied in the limit of
the renormalised current heavy quark mass m_R --> infinity. We are particularly
interested in the analytic pole structure of the heavy quark propagator in the
complex momentum plane. Approximations in which the quark-gluon vertex is
modelled by either the bare vertex or the Ball-Chiu Ansatz, and the Landau
gauge gluon propagator takes either a gaussian form or a gaussian form with an
ultraviolet asymptotic tail are used.


title: SUSY without R-parity: symmetry breaking and LSP phenomenology

abstract:
  We have studied the predictions for the LSP decay within the framework of a
radiatively broken unified supergravity model without R-parity. Assuming that
Higgs/slepton mixing is the only source of R-parity breaking and responsible
for the observed neutrino oscillations we obtain predictons for the LSP
life-time and branching fractions.


title: Tests of Higgs and Top Effective Interactions

abstract:
  We study the possibility to detect heavy physics effects in the interactions
of Higgs bosons and the top quark at future colliders using the effective
Lagrangian approach. The modification of the interactions may enhance the
production of Higgs bosons at hadron colliders through the mechanisms of gluon
fusion and associated production with a W boson or $t\bar{t}$ pairs. The most
promising signature is through the decay of the Higgs boson into two photons,
whose branching ratio is also enhanced in this approach. As a consequence of
our analysis we get a bound on the chromomagnetic dipole moment of the top
quark.


title:
Z-gamma-Higgs vertex effects in Higgs production at future e-gamma
  linear colliders

abstract:
  One-loop production of a Higgs boson in electro-photon collisions at future
accelerators is studied via the process (e gamma -> e H), for intermediate
Higgs masses. Exact cross sections, including the possibility of longitudinally
polarized initial beams, are presented. Confirming previous estimates made in
the Weizs\"acker-Williams approximation, they are found to be more than two
orders of magnitude larger than the cross sections for the crossed process (e
e-> gamma H), in the energy range $\sqrt{s}=(0.5-2)$ TeV. We show that, not
only (e gamma -> e H) has a similar potential as the (gamma gamma -> H) process
for testing the one-loop gamma-gamma-H vertex, but, by requiring a final
electron tagged at large angle in (e gamma -> e H), the (H e) production
provides an excellent way of testing the Z-gamma-H vertex, too. Kinematical
distributions for the (e gamma -> e H -> e bb) process with a tagged final
electron are analyzed, and strategies for controlling the main irreducible
background are found. Initial-state-radiation effects are checked to be within
a few percent.


title:
Constraining the $SU(2)_R$ breaking scale in naturally R-parity
  conserving supersymmetric models

abstract:
  We obtain a relation between right-handed gauge boson mass and soft squark
mass in naturally R-parity conserving general supersymmetric left-right models.
This relation implies that either ${W_R}$ is lighter than twice the soft squark
mass, or a ratio of vacuum expectation values (VEVs) in the model, denoted by
$\tan\alpha$, is close to its value of unity in the limit of vanishing D-terms.
Generally, we find that for heavy $W_R$ $\tan\alpha$ is larger than one, and
that the right-handed sneutrino VEV, responsible for spontaneous R-parity
breaking, is at most of the order $M_{SUSY}/h_{\Delta_R}$, where $M_{SUSY}$ is
supersymmetry breaking scale and $h_{\Delta_R}$ is the Yukawa coupling in
Majorana mass term for right-handed neutrinos. These constraints follow from
$SU(3)_c$ and $U(1)_{em}$ gauge invariance of the ground state of the theory.


title: Flavor Physics and the Triviality Bound on the Higgs Mass

abstract:
  The triviality of the scalar sector of the standard one-doublet Higgs model
implies that this model is only an effective low-energy theory valid below some
cut-off scale $\Lambda$. The underlying high-energy theory must include flavor
dynamics at a scale of order $\Lambda$ or greater in order to give rise to the
different Yukawa couplings of the Higgs to ordinary fermions. This flavor
dynamics will generically produce flavor-changing neutral currents and
non-universal corrections to Z -> b b-bar. We show that the experimental
constraints on the neutral D-meson mass difference imply that $\Lambda$ must be
greater than of order 21 TeV. We also discuss bounds on $\Lambda$ from the
constraints on extra contributions to the K_L - K_S mass difference and to the
coupling of the Z boson to b-quarks. For theories defined about the
infrared-stable Gaussian fixed-point, we estimate that this lower bound on
$\Lambda$ yields an upper bound of approximately 460 GeV on the Higgs boson's
mass, independent of the regulator chosen to define the theory.


title:
Virtualities of Quarks and Gluons in QCD Vacuum and Nonlocal Condensates
  within Single Instanton Approximation

abstract:
  We calculate the lowest-dimensional nonlocal quark and gluon condensates
within the single instanton approximation of the instanton liquid model. As a
result, we determine the values of average virtualities of quarks $\lambda_q^2$
and gluons $\lambda_g^2$ in the QCD vacuum and obtain parameterless predictions
for the ratio $\lambda_g^2/\lambda_q^2 = 12/5$, and for some ratios of
different vacuum condensates of higher dimensions. The nonlocal properties of
quark and gluon condensates are analyzed, and insufficiency of the single
instanton approximation is discussed.


title: Structure functions and angular ordering at small x

abstract:
  We compute the gluon distribution in deep inelastic scattering at small x by
solving numerically the angular ordering evolution equation. The leading order
contribution, obtained by neglecting angular ordering, satisfies the BFKL
equation. Our aim is the analysis of the subleading corrections. Although not
complete - the exact next-to-leading contribution is not yet available - these
corrections are important since they come from the physical property of
coherence of QCD radiation. In particular we discuss the subleading correction
to the BFKL characteristic function and the gluon distribution's dependence on
the maximum available angle. Conformal invariance of the BFKL equation is lost,
however this is not enough to bring the small-x gluon distribution into the
perturbative regime: although large momentum regions are enhanced by angular
ordering, the small momentum regions are not fully suppressed. As a
consequence, the gluon anomalous dimension is finite and tends to the BFKL
value $\gamma=1/2$ for $\alpha_S \to 0$. The main physical differences with
respect to the BFKL case are that angular ordering leads to 1) a larger gluon
anomalous dimension, 2) less singular behaviour for $x \to 0$ and 3) reduced
diffusion in transverse momentum.


title: On the importance of testing gravity at distances less than 1cm

abstract:
  If the mechanism responsible for the smallness of the vacuum energy is
consistent with local quantum field theory, general arguments suggest the
existence of at least one unobserved scalar particle with Compton wavelength
bounded from below by one tenth of a millimeter. We show that this bound is
saturated if vacuum energy is a substantial component of the energy density of
the universe. Therefore, the success of cosmological models with a significant
vacuum energy component suggests the existence of new macroscopic forces with
range in the sub-millimeter region. There are virtually no experimental
constraints on the existence of quanta with this range of interaction.


title: QCD corrections to B -> J/psi + anything

abstract:
  We calculate the branching ratio for B -> J/psi + anything, within the
color-singlet approximation for J/psi production, but including perturbative
QCD corrections beyond the leading logarithm approximation. Such higher order
corrections are necessary, in order to obtain a result that is not strongly
dependent on the renormalization scale. As in the earlier work of Bergstrom and
Ernstrom, we use a double expansion in alpha_s and in the small ratio of Wilson
coefficients L_0/L_2, to identify the dominant terms in the decay amplitude. We
complete their work by calculating all the leading order terms in this double
expansion. The predicted branching ratio is then BR(B -> J/psi + anything) =
0.09 (+1.1)(-0.3) %, which is well below the experimental value
BR(experimental) = 0.80 (+-0.08) %. This confirms the suspicion that
non-perturbative corrections to the color-singlet approximation for J/psi
production in B decays are important.


title: Sneutrino Mixing Phenomena

abstract:
  In any model with nonzero Majorana neutrino masses, the sneutrino and
antisneutrino of the supersymmetric extended theory mix. We outline the
conditions under which sneutrino-antisneutrino mixing is experimentally
observable. The mass-splitting of the sneutrino mass eigenstates and sneutrino
oscillation phenomena are considered.


title: Self-Energy of Decuplet Baryons in Nuclear Matter

abstract:
  We calculate, in chiral perturbation theory, the change in the self-energy of
decuplet baryons in nuclear matter. These self-energy shifts are relevant in
studies of meson-nucleus scattering and of neutron stars. Our results are
leading order in an expansion in powers of the ratio of characteristic momenta
to the chiral symmetry-breaking scale (or the nucleon mass). Included are
contact diagrams generated by 4-baryon operators, which were neglected in
earlier studies for the $\Delta$ isomultiplet but contribute to the self-energy
shifts at this order in chiral perturbation theory.


title: Supersymmetric Baryogenesis at the Electroweak Phase Transition

abstract:
  We study the possibility of baryogenesis in the case of supersymmetry
breaking with large mixing between the right-handed scalar charm and
right-handed scalar top or right-handed scalar up and right-handed scalar top
squarks resulting in one light right-handed up-type squark mass eigenstate. We
argue that in this case the electroweak phase transition will be first order,
and that large phases already present in the quark mass matrices can generate a
baryon asymmetry of the correct magnitude without introducing any new phases
specifically for this purpose. We study in detail a particular ansatz for
supersymmetry breaking and CP violation where there is only one CP violating
phase in the theory: in the up-type quark mass matrix. We study the constraints
placed on this model by baryogenesis and flavor physics. This scenario has
robust implications for low energy flavor phsyics including D-Dbar mixing and
an electric dipole moment for the neutron that are close to the experimental
bounds, and CP violation in the B-Bbar system that is different from that in
the Standard Model.


title: Two-Loop Four-Gluon Amplitudes in N=4 Super-Yang-Mills

abstract:
  Using cutting techniques we obtain the two-loop N=4 super-Yang-Mills helicity
amplitudes for four-gluon scattering in terms of scalar integral functions. The
N=4 amplitudes are considerably simpler than corresponding QCD amplitudes and
therefore provide a testing ground for exploring two-loop amplitudes. The
amplitudes are constructed directly in terms of gauge invariant quantities and
therefore remain relatively compact throughout the calculation. We also present
a conjecture for the leading color four-gluon amplitudes to all orders in the
perturbative expansion.


title: Phenomenological interaction between current quarks

abstract:
  We construct a phenomenological model which describes the dynamical chiral
symmetry breaking (DCSB) of QCD vacuum and reproduces meson spectra. Quark
condensates, the pion decay constant, and meson spectra are well reproduced by
phenomenological interaction which consists of a linear confining potential, a
Coulombic potential, and the 't Hooft determinant interaction. In this model,
the 't Hooft determinant interaction plays a important role not to only
\eta,\eta' mass difference, but other meson masses through DCSB.


title: SUSY Higgs Boson Decays into Scalar Quarks: QCD Corrections

abstract:
  In supersymmetric theories, the decays of the neutral CP-even and CP-odd as
well as the charged Higgs bosons into scalar quarks, in particular into top and
bottom squarks, can be dominant if they are kinematically allowed. We calculate
the QCD corrections to these decay modes in the minimal supersymmetric
extension of the Standard Model, including all quark mass terms and squark
mixing. These corrections turn out to be rather large, altering the decay
widths by an amount which can be larger than 50%. The corrections can be either
positive or negative, and depend strongly on the mass of the gluino. We also
discuss the QCD corrections to the decays of heavy scalar quarks into light
scalar quarks and Higgs bosons.


title: A Hamilton-Jacobi approach to non-slow-roll inflation

abstract:
  I describe a general approach to characterizing cosmological inflation
outside the standard slow-roll approximation, based on the Hamilton-Jacobi
formulation of scalar field dynamics. The basic idea is to view the equation of
state of the scalar field matter as the fundamental dynamical variable, as
opposed to the field value or the expansion rate. I discuss how to formulate
the equations of motion for scalar and tensor fluctuations in situations where
the assumption of slow roll is not valid. I apply the general results to the
simple case of inflation from an ``inverted'' polynomial potential, and to the
more complicated case of hybrid inflation.


title: Covariant treatment of neutrino oscillations

abstract:
  We perform a covariant wavepacket analysis of neutrino oscillations taking
into account the lifetime of the neutrino production process . We find that
flavour oscillations in space are washed out when the neutrinos are produced
from long lived resonances - and what may be observed in
appearance/disappearance experiments is a uniform conversion probability
independent of distance.
  The lifetime of the resonance which produces the neutrinos acts as the the
effective baseline of the experiment.
  For this reason the LSND experiment where neutrinos are produced from muon
decay has two orders of magnitude more sensitivity to neutrino mass square
difference than other experiments where the neutrinos are produced from pion or
kaon decays.We also show that there are no EPR type oscillations of the
secondary decay particles.


title:
Effects for atmospheric neutrino experiments from electron neutrino
  oscillations

abstract:
  The minimal interpretation of the atmospheric neutrino data suggests that the
muon neutrino oscillates into another species with a mixing angle close to the
maximal $\pi/4$. In the Exact Parity Symmetric Model, both the muon and
electron neutrinos are expected to be maximally mixed with essentially sterile
partners ($\nu'_{\mu}$ and $\nu'_e$ respectively). We examine the impact of
maximal $\nu_e - \nu'_e$ oscillations on the atmospheric neutrino experiments.
We estimate that maximal $\nu_e - \nu'_e$ oscillations will have effects on
atmospheric neutrino data for $|\delta m^2 (\nu_e - \nu_e')| > 7 \times 10^{-5}
eV^2$. For $\delta m^2$ in this range, a slight but distinctive rise in the
ratio of muon-like to electron-like events is predicted for the low-energy
sample. Furthermore, the ratio of low-energy electron-like events with zenith
angles less than $90\deg$ to those with zenith angles greater than $90\deg$
should be greater than 1.


title: Neutrino physics from a U(2) flavor symmetry

abstract:
  We consider the neutrino physics of models with a sequentially broken U(2)
flavor symmetry. Such theories yield the observed pattern of quark and lepton
masses, while maintaining sufficient degeneracies between superparticles of the
first two generations to solve the supersymmetric flavor problem. Neutrino mass
ratios and mixing angles in these models may differ significantly from those of
the charged leptons, even though the neutrinos and charged leptons transform
identically under the flavor group. A wide class of well-motivated U(2)
theories yield order one $\nu_\mu - \nu_\tau$ mixing, without a fine-tuning of
parameters. These models provide a natural solution to the atmospheric neutrino
deficit, and also have distinctive signatures at long-baseline neutrino
oscillation experiments.


title: What is the mass of the lightest supersymmetric Higgs boson?

abstract:
  After reviewing briefly the upper bounds on the mass of the lightest Higgs
boson in the most general unconstrained minimal supersymmetric extension of the
Standard Model, we discuss various arguments which reduce the parameter space
of the model and give stronger predictions for $M_{h^0}$. First, the
constraints from the presently available experimental data are summarized.
Next, the role of of several additional theoretical assumptions is studied,
after extrapolating the model to high energy scales. The most important ones
are: perturbative validity up to the GUT scale and the electroweak symmetry
breaking. A Higgs boson with $M_{h^0}<$100 GeV is predicted in several
scenarios. Its absence in that mass range will have important implications for
the parameter space of the model.


title: The Higgs Particle as a Self Consistent Bound State

abstract:
  We consider Higgs-Higgs scattering in a minimal Higgs model with strong
coupling which leads to the Higgs as a bound state. The partial wave amplitude
is unitarized using general principles of analyticity. We find lambda(m_H)/16pi
is approximately 1/2. A Higgs mass of approximately 1 TeV follows from m_H =
sqrt{lambda/2} * v (spontaneous symmetry breaking).


title:
Blue Perturbation Spectra from Hybrid Inflation with Canonical
  Supergravity

abstract:
  We construct a hybrid inflationary model associated with the superheavy scale
of supersymmetric grand unified theories in which the inflaton potential is
provided entirely by canonical supergravity. We find that the spectrum of
adiabatic density perturbations is characterized by a strongly varying spectral
index which is considerably larger than unity. Moreover, the total number of
e-foldings is very limited. Implications of our analysis for other hybrid
inflationary scenarios are briefly discussed.


title: Gluon Confinement

abstract:
  In this paper we present a new model for a gauge field theory such that
self-interacting spin-one particles can be confined in a compact domain. The
necessary conditions to produce the confinement appear already in the
properties of the eikonal structure generated by the particular choice of the
dynamics. The gluons do not follow along Minkowski null cone and thus can be
equivalently interpreted as if they were massive.


title:
The (alpha_s)^3 approximation of Quantum Chromodynamics to the
  Ellis-Jaffe sum rule

abstract:
  We present the analytical calculation in perturbative Quantum Chromodynamics
of the (alpha_s)^3 contribution to the Ellis-Jaffe sum rule for the structure
function g1 of polarized deep inelastic lepton-nucleon scattering.


title: Resonant spin-flavour precession of neutrinos and pulsar velocities

abstract:
  Young pulsars are known to exhibit large space velocities, up to $10^3$ km/s.
We propose a new mechanism for the generation of these large velocities based
on an asymmetric emission of neutrinos during the supernova explosion. The
mechanism involves the resonant spin-flavour precession of neutrinos with a
transition magnetic moment in the magnetic field of the supernova. The
asymmetric emission of neutrinos is due to the distortion of the resonance
surface by matter polarisation effects in the supernova magnetic field. The
requisite values of the field strengths and neutrino parameters are estimated
for various neutrino conversions caused by their Dirac or Majorana-type
transition magnetic moments.


title:
Amplitude Spectroscopy with Meson Beams at JHP:Search for New Physics
  Beyond Standard Quark Model

abstract: The paper has been withdrawn


title:
Spin Physics and Amplitude Imaging of Hadron Reactions at Japanese
  Hadron Project

abstract: The paper has been withdrawn


title: An evaluation of the analytic continuation by duality technique

abstract:
  In Nucl. Phys. B391 (1993) 127, the value of the oblique correction parameter
S for walking technicolor theories was estimated using a technique called
Analytic Continuation by Duality (ACD). We apply the ACD technique to the
perturbative vacuum polarization function and find that it fails to reproduce
the well known result S=1/6\pi. This brings into question the reliability of
the ACD technique and the ACD estimate of S.


title: ACD estimation of the S parameter revisited

abstract:
  The analytic continuation by duality (ACD) technique has been used to
estimate the electroweak S parameter in technicolor models. In this letter, we
investigate the reliability of this method by applying it to some toy models
with known spectra. We find that in most instances the technique cannot be
trusted to give a reliable result.


title: Light Fermion Mass Effects in e^+e^- -> 4 Fermions

abstract:
  We investigated the effect of the light fermion masses on cross sections for
e^+e^- into 4 fermions in the Fermion Loop scheme defined in hep-ph/9612260,
and approximations to it. The effects are found to be very small, except of
course in the collinear region of single W-boson production where the electron
mass acts as the cut-off.


title:
R_b in Supergravity Grand Unification with Non-universal Soft SUSY
  Breaking

abstract:
  An analysis of supersymmetric contributions to R_b in supergravity grand
unification with non-universal boundary conditions on soft SUSY breaking in the
scalar sector is given. Effects on R_b of Planck scale corrections on gaugino
masses are also analysed. It is found that there exist regions of the parameter
space where positive corrections to R_b of size $\sim 1 \sigma$ can be gotten.
The region of the parameter space where enhancement of R_b occurs is
identified. Prediction of the full sparticle spectrum for the maximal R_b case
is given. The analysis has implications for the discovery of supersymmetric
particles at colliders.