title: The spin-dependent two-loop splitting functions

abstract:
  We present a complete description of the calculation of the spin-dependent
next-to-leading order splitting functions. The calculation is performed in the
light-cone gauge. We give results for different prescriptions for the Dirac
matrix $\gamma_5$ in $d=4-2 \epsilon$ dimensions and provide the link to the
results in dimensional reduction.


title:
Perturbative QCD study on the photonic penguin contributions to the
  decay $B\to K^* \gamma$

abstract:
  Including corrections of order $O(m_{K^*}/m_B)$, we present an analysis of
photonic penguin contributions to the decay $B\to K^* \gamma$ in the
perturbative QCD framework. Employing several models of the meson wave
functions, we demonstrate that the corrections of $O(m_{K^*}/m_B)$ are enhanced
and will providesubstantial contributions to the decay because of the B meson
wave function being sharply peaked (bound state effect). The numerical
predictions for the corrections are about $30%\sim 60%$ which depend on the
non-perturbative inputs such as the meson wave functions and the $b$-quark
mass.


title: SUSY Decays of Higgs Particles

abstract:
  Among the possible decay modes of Higgs particles into supersymmetric states,
neutralino and chargino decays play a prominent r\^ole. The experimental
opportunities of observing such decay modes at LEP2 and at future e+e- linear
colliders are analyzed within the frame of the Minimal Supersymmetric extension
of the Standard Model. For heavy Higgs particles, the chargino/neutralino decay
modes can be very important, while only a small window is open for the lightest
CP-even Higgs particle. If charginos/neutralinos are found at LEP2, such decay
modes can be searched for in a small area of the parameter space, and invisible
decays may reduce the exclusion limits of the lightest CP-even Higgs particle
slightly; if charginos/neutralinos are not found at LEP2 in direct searches,
the Higgs search will not be affected by the SUSY particle sector.


title: A Geometric Picture For Fermion Masses

abstract:
  We describe a geometric picture for the pattern of fermion masses of the
three generations which is invariant with respect to the renormalization group
below the electroweak scale. Moreover, we predict the upper limit for the ratio
between the Dirac masses of the $\mu$ and $\tau$ neutrinos, $m_{\nu_{\mu}}/
m_{\nu_{\tau}} < (9.6 \pm 0.6) 10^{-3}$.


title: Unification of Couplings in the MSSM

abstract:
  I briefly summarize the main features related to the unification of gauge and
Yukawa couplings in the MSSM, emphasizing the predictions derived in this
framework, which are of special interest in the light of present and
near--future experiments


title: Quarks, Squarks and Textures

abstract:
  By studying symmetric mass textures for the up and down quark sectors, and
expanding in a small parameter $\lambda \sim sin\theta_C$, bounds are set on
entries commonly assumed to vanish. Consequences of a 2 + 1 family structure
which can result from horizontal symmetry are examined. Generalizing to
squarks, we study suppression of Flavor Changing Neutral Currents by mass
degeneracy and/or small mixing angles.


title: Horizontal Symmetry for Quark and Squark Masses in Supersymmetric SU(5)

abstract:
  Recent interest in horizontal symmetry model building has been driven mainly
by the large top mass and hence strong hierarchy in quark masses, and the
possibility of appropriately constrained soft squark mass matrices, in place of
an assumed universality condition, for satisfying the relevant FCNC
constraints. Here we present the first successful SUSY-$SU(5)$ model that has
such a feature. The horizontal symmetry is a gauged $(Q_{12} \times U(1))_H$
($\subset (SU(2) \times U(1))_H$). All nonrenormalizable terms compatible with
the symmetry are allowed in the mass matrix constructions. Charged lepton
masses can also be accommodated.


title:
Numerical Study of Spectrum and HBT Radii for Three-Dimensionally
  Expanding, Cylindrically Symmetric, Finite Systems

abstract:
  This study is devoted to a detailed numerical testing of the analytical
results obtained recently for the $M_t$-scaling of the parameters of the
Bose-Einstein correlation functions. Numerical testing of analytical results
for the spectrum is also performed, since the geometrical sizes are folded into
the momentum distribution in the scaling limiting case. The analytical results
are shown to be valid in a wider rapidity-range than thought before.


title: Two-loop heavy top effects on the MZ-MW interdependence

abstract:
  The O(alpha^2 mt^2/mw^2) correction to the relation between G_\mu and the
vector boson masses is computed in the MSbar scheme, and the results are used
to investigate the magnitude of the effect on the theoretical prediction of mw
and sin^2\theta_\msbar(mz) from alpha, G_\mu, and mz.


title: Higher-twist Effects in Spin Structure Functions

abstract:
  We discuss the QCD effects of the higher-twist operators in the nucleon
spin-dependent structure functions measured by the polarized deep inelastic
leptoproduction.
  We particularly study the renormalization of the twist-3 and twist-4
operators within the framework of operator product expansions and
renormalization group methods in perturbative QCD.
  Emphasis will be placed on the role of the operators proportional to equation
of motion which appear in the mixing of the higher-twist operators through
renormalization.
  The logarithmic and power corrections in $Q^2$ due to the lowest spin
higher-twist operators are discussed for the first moment of $g_1$ structure
function, Bjorken and Ellis-Jaffe sum rules, as well as the lower moments of
$g_2$ structure function.


title: Neutrino Mixing in a Democratic-Seesaw-Mass-Matrix Model

abstract:
  On the basis of a seesaw-type mass matrix model for quarks and leptons, $M_f
\simeq m_L M_F^{-1} m_R$, where $m_L\propto m_R$ are universal for $f=u,d,\nu$
and $e$ (up-quark-, down-quark-, neutrino- and charged lepton-sectors), and
$M_F$ has a form [(unit matrix)+(democratic-type matrix)], neutrino masses and
mixings are investigated. It is tried to understand a large
$\nu_\mu$-$\nu_\tau$ mixing, i.e., $\sin^2 2\theta_{23}\sim 1$, with $m_{\nu 1}
\ll m_{\nu 2} \sim m_{\nu 3}$, which has been suggested by the atmospheric
neutrino data.


title: QCD Corrections to the nucleon's spin structure function $G_2(x,Q^2)$

abstract:
  We investigate the renormalization of the twist-3 operators which are
relevant for the spin-dependent structure function $g_{2}(x, Q^{2})$. We derive
the anomalous dimension for the non-singlet part by calculating the off-shell
Green's functions of the twist-3 operators including the operators which are
proportional to the equation of motion.


title: Classical decay of inflaton

abstract:
  We present the first fully non-linear calculation of inflaton decay. We map
inflaton decay onto an equivalent classical problem and solve the latter
numerically. In the $\lambda\phi^4$ model, we find that parametric resonance
develops slower and ends at smaller values of fluctuating fields, as compared
to estimates existing in literature. We also observe a number of qualitatively
new phenomena, including a stage of semiclassical thermalization, during which
the decay of inflaton is essentially as effective as during the resonance
stage.


title: Spontaneous breakdown of CP in left-right symmetric models

abstract:
  We show that it is possible to obtain spontaneous CP violation in the minimal
$SU(2)_L \times SU(2)_R \times U(1)_{B-L}$, i.e. in a left right symmetric
model containing a bidoublet and two triplets in the scalar sector. For this to
be a natural scenario, the non-diagonal quartic couplings between the two
scalar triplets and the bidoublet play a fundamental role. We analyze the
corresponding Higgs spectrum, the suppression of FCNC's and the manifestation
of the spontaneous CP phase in the electric dipole moment of the electron.


title:
The Effects of a New Vector Boson on the Top Quark Cross Section at the
  Tevatron

abstract:
  It has recently been shown that a new neutral vector boson $Z'$, with a mass
of order 1~TeV and weak couplings to quarks only, could explain both the
anomalous values of $R_b$ and $R_c$ and the apparent excess of large $E_T$ jet
events measured by the CDF collaboration. We calculate the effects of $Z'$
exchange on the $t\bar{t}$ production cross section at Tevatron $p \bar p$
collider energies, including next-to-leading-order QCD corrections. We find a
significant enhancement of the cross section and study the resulting $t \bar t$
invariant mass distribution, which could provide a decisive test of the $Z'$
model.


title:
Detection of minijet production in $\sqrt{s}$=1.8 TeV proton-antiproton
  collisions with multi-particle transverse energy correlation functions

abstract:
  Multi-particle transverse energy correlation(MTEC) functions are proposed to
study minijet production in high energy proton-antiproton collisions.
Obtainable with both the D0 and the CDF detector, the high-order MTEC functions
are shown to be sensitive probes of jet internal structure as well as promising
observables of detecting minijet production in $\sqrt{s}$=1.8 TeV $p\bar{p}$
collisions.


title: Shadowing of Ultrahigh Energy Neutrinos

abstract:
  The rise with energy of the neutrino--nucleon cross section implies that at
energies above few TeV the Earth is becoming opaque to cosmic neutrinos. The
neutrinos interact with the nucleons through the weak charged current,
resulting into absorption, and the weak neutral current, which provides a
redistribution of the neutrino energy. We Mellin transform the neutrino
transport equation and find its exact solution in the moment space. A simple
analytical formula is provided, which describes accurately the neutrino
spectrum, after the neutrinos have traversed the Earth. The effect of the weak
neutral current is most prominent for an initial flat neutrino spectrum and we
find that at low energies (around 1 TeV) the neutrino intensity is even
enhanced.


title:
The Standard Model process $e^+e^-\to \nu\bar{\nu}b\bar{b}$ and its
  Higgs signal at LEPI

abstract:
  We present and study the results for the standard model process $e^+e^-\to
\nu\bar{\nu}b\bar{b}$ at c.m energies 150$\leq \sqrt{s} (GeV) \leq $ 240 and
for Higgs boson masses $80 GeV \leq m_H \leq 120 GeV$, obtained from all
tree-level diagrams and including the most important radiative corrections. The
$\sqrt{s}$ dependence and the interference properties of the Higgs boson
contribution and of various coherent background contributions to the total
cross section are examined. The effect of the QED initial state radiative
corrections is estimated. The important differential distributions for the
Higgs boson and the background components are studied, providing information
usefull for choosing cuts in Higgs searches. We also examine the effect of a
minimal set of cuts and evaluate the importance of the WW fusion for detecting
a higher mass Higgs boson at LEPII.


title:
Motion of Chern-Simons Number at High Temperature Under a Chemical
  Potential

abstract:
  I investigate the evolution of finite temperature, classical Yang-Mills field
equations under the influence of a chemical potential for Chern Simons number
$N_{CS}$. The rate of $N_{CS}$ diffusion, $\Gamma_d$, and the linear response
of $N_{CS}$ to a chemical potential, $\Gamma_\mu$, are both computed; the
relation $\Gamma_d = 2 \Gamma_\mu$ is satisfied numerically and the results
agree with the recent measurement of $\Gamma_d$ by Ambjorn and Krasnitz. The
response of $N_{CS}$ under chemical potential remains linear at least to $\mu =
6 T$, which is impossible if there is a free energy barrier to the motion of
$N_{CS}$. The possibility that the result depends on lattice artefacts via hard
thermal loops is investigated by changing the lattice action and by examining
elongated rectangular lattices; provided that the lattice is fine enough, the
result is weakly if at all dependent on the specifics of the cutoff. I also
compare SU(2) with SU(3) and find $\Gamma_{\rm SU(3)} \sim 7
(\alpha_s/\alpha_w)^4 \Gamma_{\rm SU(2)}$.


title: A New Calculation of the NLO Energy-Energy Correlation Function

abstract:
  We present a new calculation of the $O(\alpha_s^2)$ coefficient of the
energy-energy correlation function (EEC) using two different schemes to cancel
infrared and collinear poles. The numerical evaluation uses the phase space
slicing and the hybrid subtraction method. Both schemes converge with
decreasing slicing cut. The results are independent of the scheme for small
cuts. For the pure phase space slicing method, the cut must be below $10^{-6}$
to achieve good results. All four approaches agree with each other and confirm
the results of Kunszt and Nason and Glover and Sutton, for the latter also with
respect to contributions of different colour factors.


title:
$N=1$ supersymmetry and the three loop anomalous dimension for the
  chiral superfield

abstract:
  We calculate the three loop anomalous dimension for a general $N=1$
supersymmetric gauge theory. The result is used to probe the possible existence
of renormalisation invariant relationships between the Yukawa and gauge
couplings.


title: Chiral symmetry and QCD sum rules for the nucleon mass in matter

abstract:
  The quark condensate in nuclear matter contains a term of order $\rho m_\pi$,
arising from the contribution of low-momentum virtual pions to the $\pi N$
sigma commutator. Standard treatments of QCD sum rules for a nucleon in matter
generate a similar term in the nucleon effective mass, although this is
inconsistent with chiral perturbation theory. We show how an improved treatment
of pionic contributions on the phenomenological side of the sum rules can
cancel out this unwanted piece. Our results also show that factorisation ansatz
for the four-quark condensate cannot be valid in matter.


title: Electroweak Baryogenesis in the Next to Minimal Supersymmetric Model

abstract:
  In the electroweak phase transition there arises the problem of baryon number
washout by sphaleron transitions, which can be avoided if the phase transition
is strongly enough first order. The minimal supersymmetric standard model has
just two Higgs doublets H1 and H2, while the next to minimal model, NMSSM, has
an additional singlet, N, this latter giving rise to the helpful feature that
the Higgs potential contains a tree level trilinear field term. We use the
tunneling criterion for the existence of a first order electroweak phase
change. A quantitative statistical analysis indicates that with parameters of
the NMSSM satisfying the experimental constraints a strong first order phase
change occurs in about 50% of cases.


title: A New Interpretation of the Observed Heavy Baryons

abstract:
  I suggest that the conventional assignment of quantum numbers to the observed
charm and bottom baryons is not correct, as these assignments imply large
violation of the heavy spin-flavor and light $SU(3)$ symmetries. I propose an
alternative interpretation of the observed states, in which the symmetries are
preserved. If these novel assignments are right, there is a new state with mass
approximately 2380~MeV which decays to $\Lambda_c+\gamma$, and another with
mass approximately 5760~MeV which decays to $\Lambda_b+\gamma$. Although such
states have not been seen, neither are they excluded by current analyses.


title: Light Gluino And Squark Production In Dijet Experiments At Tevatron

abstract:
  We consider single squark production in $p\overline{p}$ collisions at
$\sqrt{s}=1800$ Gev in the light gluino scenario, where production is dominated
by the parton subprocess $qg\rightarrow \tilde{q}\tilde{g}\rightarrow
q\tilde{g}\tilde{g}$. Computed are the total production cross-sections as well
as the contribution of such production to the dijet mass distribution. We
compare our cross-sections to the experimental data from the CDF collaboration
with integrated luminosity of $19 pb^{-1}$.


title: Indirect Probes of New Physics

abstract:
  We summarize the indirect effects of new physics in a variety of processes.
We consider precision electroweak measurements, the $g-2$ of the muon, rare
decays, meson mixing, CP violation, lepton number violating interactions,
double beta decay, and the electric dipole moments of atoms, molecules, and the
neutron. We include discussions of both model independent and dependent
analyses where applicable.


title: Neutrino Clouds

abstract:
  We consider the possibility that neutrinos are coupled very weakly to an
extremely light scalar boson. We first analyze the simple problem of one
generation of neutrino and show that, for ranges of parameters that are allowed
by existing data, such a system can have serious consequences for the evolution
of stars and could impact precision laboratory measurements. We discuss the
extension to more generations and show that the general conclusion remains
viable. Finally, we note that, should such a scalar field be present,
experiments give information about effective masses, not the masses that arise
in unified field theories.


title: The Unitarity Triangle and Quark Mass Matrices on the NNI Basis

abstract:
  We examine the unitarity triangle of the KM matrix by using the general quark
mass matrices on the NNI basis. The Fritzsch anz\"atz is modified by
introducing four additional parameters. The KM matrix elements are expressed in
terms of quark mass ratios, two phases and four additional parameters. It is
found that the vertex of the unitarity triangle is predicted to be almost in
the second quadrant on the $\rho -\eta$ plane as far as $V_{us}\simeq
-{\displaystyle \sqrt{\frac{m_d}{m_s}}e^{ip}+ \sqrt{\frac{m_u}{m_c}}e^{iq}}$ is
held.


title: grc4f v1.0: a Four-fermion Event Generator for e+e- Collisions

abstract:
  grc4f is a Monte-Carlo package for generating e+e- to 4-fermion processes in
the standard model. All of the 76 LEP-2 allowed fermionic final state processes
evaluated at tree level are included in version 1.0. grc4f addresses event
simulation requirements at e+e- colliders such as LEP and up-coming linear
colliders. Most of the attractive aspects of grc4f come from its link to the
GRACE system: a Feynman diagram automatic computation system. The GRACE system
has been used to produce the computational code for all final states, giving a
higher level of confidence in the calculation correctness. Based on the
helicity amplitude calculation technique, all fermion masses can be kept finite
and helicity information can be propagated down to the final state particles.
The phase space integration of the matrix element gives the total and
differential cross sections, then unweighted events are Generated. Initial
state radiation (ISR) corrections are implemented in two ways, one is based on
the electron structure function formalism and the second uses the parton shower
algorithm called QEDPS. The latter can also be applied for final state
radiation (FSR) though the interference with the ISR is not yet taken into
account. Parton shower and hadronization of the final quarks are performed
through an interface to JETSET. Coulomb correction between two intermediate
W's, anomalous coupling as well as gluon contributions in the hadronic
processes are also included.


title: Fermion Scattering by Phase Boundaries

abstract:
  We consider interactions of fermions with the domain wall bubbles produced
during the first order phase transitions. New exact solution of Dirac equations
and reflection coefficient are obtained.


title: Long Range Forces and Neutrino Mass

abstract:
  We explore the limits on neutrino mass which follow from a study of the
long-range forces that arise from the exchange of massless or ultra-light
neutrinos. Although the 2-body neutrino-exchange force is unobservably small,
the many-body force can generate a very large energy density in neutron stars
and white dwarfs. We discuss the novel features of neutrino-exchange forces
which lead to large many-body effects, and present the formalism that allows
these effects to be calculated explicitly in the Standard Model. After
considering, and excluding, several possibilities for avoiding the unphysically
large contributions from the exchange of massless neutrinos, we develop a
formalism to describe the exchange of massive neutrinos. It is shown that the
stability of both neutrons stars and white dwarfs in the presence of many-body
neutrino-exchange forces implies a lower bound, $m \gtrsim 0.4$ eV/$c^{2}$ on
the mass $m$ of any neutrino.


title:
On the twist-2 contributions to polarized structure functions and new
  sum rules

abstract:
  The twist-2 contributions to the polarized structure functions in deep
inelastic lepton--hadron scattering are calculated including the exchange of
weak bosons and using both the operator product expansion and the covariant
parton model. A new relation between two structure functions leading to a
sequence of new sum rules is found. The light quark mass corrections to the
structure functions are derived in lowest order QCD.


title:
Top pair production in e+ e- collisions with virtual and real
  electroweak radiative corrections

abstract:
  The effect of virtual electroweak corrections to $e^+e^- \rightarrow t
\bar{t}$ and the contribution of the radiation processes $e^+e^- \rightarrow
t\bar{t}Z, t\bar{t}H$ to the inclusive top pair production cross section and
forward-backward asymmetry are discussed in the high energy regime.


title:
Tests of the Standard Model and its Extensions in High-Energy e+e-
  Collisions

abstract:
  This thesis concerns the testing of the SM and its extensions in e+e-
collisions, the main emphasis being on neutrino physics (abridged abstract).


title: Hadro-production of Quarkonia in Fixed Target Experiments

abstract:
  We analyze charmonium and bottomonium production at fixed target experiments.
We find that inclusion of color octet production channels removes large
discrepancies between experiment and the predictions of the color singlet model
for the total production cross section. Furthermore, including octet
contributions accounts for the observed direct to total $J/\psi$ production
ratio. As found earlier for photo-production of quarkonia, a fit to fixed
target data requires smaller color octet matrix elements than those extracted
from high-$p_t$ production at the Tevatron. We argue that this difference can
be explained by systematic differences in the velocity expansion for collider
and fixed-target predictions. While the color octet mechanism thus appears to
be an essential part of a satisfactory description of fixed target data,
important discrepancies remain for the $\chi_{c1}/\chi_{c2}$ production ratio
and $J/\psi$ ($\psi'$) polarization. These discrepancies, as well as, the
differences between pion and proton induced collisions emphasize the need for
including higher twist effects in addition to the color octet mechanism.


title: Fermion Scattering at a Phase Wave

abstract:
  We study fermion reflection at a phase wave which is formed during a bubble
collision in a first order phase transition. We calculate the reflection and
the transmission coefficients by solving the Dirac equation with the phase wave
background. Using the results we analyze the damping and the velocity of the
wave.


title: Singularity-Free Breit Equation from Constraint Two-Body Dirac Equations

abstract:
  We examine the relation between two approaches to the quantum relativistic
two-body problem: (1) the Breit equation, and (2) the two-body Dirac equations
derived from constraint dynamics. The Breit equation is known to be
pathological when singularities appear at finite separations $r$ in the reduced
set of coupled equations for attractive potentials even when the potentials
themselves are not singular there. They then give rise to unphysical bound
states and resonances. In contrast, the two-body Dirac equations of constraint
dynamics do not have these pathologies in many nonperturbative treatments. To
understand these marked differences, we first express these contraint equations
in a hyperbolic form. These coupled equations are then re-cast into two
equivalent equations: (1) a covariant Breit-like equation with potentials that
are exponential functions of certain ``generator'' functions, and (2) a
covariant orthogonality constraint on the relative momentum. This reduction
enables us to show in a transparent way that finite-$r$ singularities do not
appear as long as the the exponential structure is not tampered with and the
exponential generators of the interaction are themselves nonsingular for finite
$r$. These Dirac or Breit equations, free of the structural singularities which
plague the usual Breit equation, can then be used safely under all
circumstances, encompassing numerous applications in the fields of particle,
nuclear, and atomic physics which involve highly relativistic and strong
binding configurations.


title: QCD phase transitions from relativistic hadron models

abstract:
  The models of translationally invariant infinite nuclear matter in the
relativistic mean field models are very interesting and simple, since the
nucleon can connect only to a constant vector and scalar meson field. Can one
connect these to the complicated phase transitions of QCD ? For an affirmative
answer to this question, one must consider models where the coupling constants
to the scalar and vector fields must depend on density in a non-linear way,
since as such the models are not explicitly chirally invariant. Once this is
ensured, indeed one can derive a quark condensate indirectly from the energy
density of nuclear matter which goes to zero at large density and temperature.
The change to zero condensate indicates a smooth phase transition.


title: Virtual $O(\a_s)$ corrections to the inclusive decay $b \to s \gamma$

abstract:
  We present in detail the calculation of the $O(\a_s)$ virtual corrections to
the matrix element for $b \to s \g$. Besides the one-loop virtual corrections
of the electromagnetic and color dipole operators $O_7$ and $O_8$, we include
the important two-loop contribution of the four-Fermi operator $O_2$. By
applying the Mellin-Barnes representation to certain internal propagators, the
result of the two-loop diagrams is obtained analytically as an expansion in
$m_c/m_b$. These results are then combined with existing $O(\a_s)$
Bremsstrahlung corrections in order to obtain the inclusive rate for $B \to X_s
\g$. The new contributions drastically reduce the large renormalization scale
dependence of the leading logarithmic result. Thus a very precise Standard
Model prediction for this inclusive process will become possible once also the
corrections to the Wilson coefficients are available.


title:
Determination of light-flavor asymmetry in the $\Sigma^{\pm}$ sea by the
  Drell-Yan process

abstract:
  We propose a flavor asymmetry in the light quark sea of $\Sigma^{\pm}$, which
can be measured in Drell-Yan experiments using charged hyperon beams on proton
and deuteron targets. Such a measurement would help to reinforce the presence
of pseudoscalar mesons in a quark model of baryons.


title: Quark Matter in Strong Magnetic Field

abstract:
  The effect of strong magnetic field on the stability and gross properties of
bulk as well as quasi-bulk quark matter has been investigated using the
conventional MIT bag model. Both the Landau diamagnetism and the paramagnetism
of quark matter has been studied. How the quark hadron phase transition is
affected by the presence of strong magnetic field has also been investigated.
The equation of state of strange quark matter changes significantly in strong
magnetic field. It is also shown that the thermal nucleation of quark bubbles
in compact metastable state of neutron matter is completely forbidden in
presence of strong magnetic field.


title:
Expulsion of Magnetic Flux Lines from Growing Superconducting Core of a
  Quark Star and The Possibility of Mullins-Sekerka Interface Instability

abstract:
  The expulsion of magnetic flux lines from a growing superconducting core of a
quark star has been investigated using the idea of impurity diffusion in molten
alloys. The possibility of Mullins-Sekerka normal-superconducting interface
instability has also been studied.


title: Transition Form Factor gamma gamma* -> pi0 and QCD sum rules

abstract:
  The transition gamma*(q_1)gamma*(q_2) -> \pi0(p) is studied within the QCD
sum rule framework. As a first step, we analyze the kinematic situation when
both photon virtualities are spacelike and large. We construct a QCD sum rule
for F(q_1^2,q_2^2) and show that, in the asymptotic limit |q_1^2|, |q_2^2| \to
\infty, it reproduces the leading-order pQCD result. Then we study the limit
|q_1^2| -> 0, in which one of the photons is (almost) real. We develop a
factorization procedure for the infrared singularities ln(q_1^2),
1/q_1^2,1/q_1^4,etc., emerging in this limit. The infrared-sensitive
contributions are absorbed in this approach by bilocal correlators, which can
be also interpreted as the distribution amplitudes for (almost) real photon.
Under explicitly formulated assumptions concerning the form of these
amplitudes, we obtain a QCD sum rule for F(q_1^2=0,q_2^2=-Q^2) and study its
Q^2-dependence. In contrast to pQCD, we make no assumptions about the shape of
the pion distribution amplitude varphi_{\pi}(x). Our results agree with the
Brodsky-Lepage proposal that the Q^2-dependence of this form factor is given by
an interpolation between its Q^2=0 value fixed by the axial anomaly and 1/Q^2
pQCD value dictated by the asymptotic form of the pion distribution amplitude.
We interpret this as an evidence that the latter is rather close to the
asymptotic form.


title: Anomalous couplings in the Higgs-strahlung process

abstract:
  The angular distributions in the Higgs-strahlung process $e^+e^-\to HZ\to
H\bar f f$ are uniquely determined in the Standard Model. We study how these
predictions are modified if non-standard couplings are present in the $ZZH$
vertex, as well as lepton-boson contact terms. We restrict ourselves to the set
of operators which are singlets under standard $SU_3\times SU_2\times U_1$
transformations, CP conserving, dimension 6, helicity conserving, and custodial
$SU_2$ conserving.


title: Production of Stop, Sbottom, and Stau at LEP2

abstract:
  We present a comprehensive study of pair production and decay of stops,
sbottoms, and staus in $e^+ e^-$ annihilation at LEP2. We give numerical
predictions within the Minimal Supersymmetric Standard Model for cross sections
and decay rates, and discuss the important signatures. In the case of stau
production we also study the polarization of the tau in the decays stau_1 ->
tau + neutralino_{1,2}.


title:
The effect of the Higgs boson on the threshold cross-section in W-pair
  production

abstract:
  We investigate the uncertainty induced by the Higgs-boson mass on the
determination of $m_W$ from the LEP-2 run near the threshold for $W$-pair
production. For a light Higgs boson the Yukawa interaction between the two
slowly-moving $W$ bosons gives rise to a correction of close to 1\% to the
total cross-section. This corresponds to a 15 MeV shift in the deduced $W$ mass
for a Higgs-boson mass of 60 GeV. We present a simple approximation for this
correction and discuss its validity.


title: Constraints on $R$-parity violating interactions from $\mu\to e\gamma$

abstract:
  The lepton number violating process $\mu\rightarrow e\gamma$ is used to study
the lepton number violating couplings in MSSM extended by terms violating
$R$-parity explicitly. Bounds are obtained for the products of $\lambda $- or
$\lambda '$-type couplings. It is found that many of these limits are more
stringent than the ones obtained previously.


title:
The Densities, Correlations and Length Distributions of Vortices
  Produced at a Gaussian Quench

abstract:
  We present a model for the formation of relativistic global vortices
(strings) at a quench, and calculate their density and correlations. The
significance of these results to early universe and condensed-matter physics is
discussed. In particular, there is always open, or infinite, string.


title:
Improved Bounds for the Slope and Curvature of $\bar B\to
  D^{(*)}\ell\bar\nu$ Form Factors

abstract:
  We derive a theoretically allowed domain for the slope $\widehat\varrho^2$
and curvature $\widehat c$ of the physical form factor appearing in the decay
$\bar B\to D^*\ell\bar\nu$. Using heavy-quark symmetry, we relate this function
to a particular $\bar B \to D$ form factor free of ground-state $B_c$ poles
below the threshold for $B D$ production, for which almost model-independent
constraints are derived from QCD using unitarity and analyticity. Our results
are of interest for the extraction of $|V_{cb}|$ from the recoil spectrum in
exclusive semileptonic $B$ decays. Making conservative estimates of the
theoretical uncertainties, we find (up to $1/m_Q$ corrections)
$\widehat\varrho^2<1.11$ and $\widehat c\simeq 0.66\widehat\varrho^2-0.11$. We
also derive the corresponding bounds for the form factor in the decay $\bar
B\to D\ell\bar\nu$.


title: The status of the determination of $\alpha(m_Z)$ and $\alpha_s(m_z)$

abstract:
  I will discuss the current status of the determination of $\alpha(m_Z)$ and
$\alpha_s(m_Z)$, emphasizing the pitfalls that one must avoid in performing
statistical analyses.


title: Gauge-boson scattering signals at the LHC

abstract:
  We have extended our earlier treatment of the gauge-boson scattering with
radiative corrections in the standard model at supercollider energies, and
computed the rates for gauge-boson scattering modes in $pp$ collisions leading
to the final states $W^+W^-$, $ZZ(4l)$, $ZZ(2l2\nu)$, $W^\pm Z$, and $W^\pm
W^\pm $. Our results at the LHC \hbox{energy} of $\sqrt{s}=14$~TeV for
$m_H=1000$~GeV are compared with those recently obtained by Bagger {\it et al.}
These results will be useful in the search for the Higgs bosons at
supercollider energies as well as for experimentally distinguishing the
standard model from non-minimal Higgs models.


title: The $c \to u \gamma$ Contribution to Weak Radiative Charm Decay

abstract:
  The $c \to u \gamma$ transition does not occur at the tree level in the
Standard Model and is strongly GIM-suppressed at one loop. The leading QCD
logarithms are known to enhance the amplitude by two orders of magnitude. We
point out that the amplitude increases further by two orders of magnitude after
including the complete 2-loop QCD contributions. Nevertheless, $\Delta S =0$
radiative decays of charmed hadrons remain dominated by the $c \to d \bar{d} u
\gamma$ and $c \to s \bar{s} u \gamma$ quark subprocesses.


title: CP symmetry and fermion masses in O(10) grand unification models

abstract:
  O(10) grand unification models which do not necessarily have an extra global
symmetry are discussed, taking the model with one 10-plet in the Yukawa sector
as an example. A strong correlation between mass ratios and CP is found. The
mass relation $m_t/m_b=v_u/v_d$ is recovered when $G_W=0$; and another special
relation $m_t/m_b=G_E/G_W$ appears when $v_d=0$, where $G_{E,W}$ are Yukawa
coupling constants and $v_{u,d}$ are VEVs. To facilitate this discussion, a set
of $O(10)$ $\gamma$- matrices is offered based on a physical representation of
the spinors and that of the vector of the $SO(10)$ group. Flavor changing
neutral currents in such models are also discussed.


title: A Possible Explanation of the CP Puzzle

abstract:
  The problem of mirror-reflection symmetry (MRS) and time-reversal symmetry
(TRS) in our world is discussed. The opinion is expressed, that well-known
experiments on parity violation and CP-violation can be treated as signals of
some new, yet unknown, level of matter. An hypothesis, which can be used as a
base for some future model or theory is formulated. In the framework of this
hypothesis, experiments which demonstrate parity violation or CP-violation do
not contradict MRS or TRS conservation.


title: Opening the Window for Electroweak Baryogenesis

abstract:
  We perform an analysis of the behaviour of the electroweak phase transition
in the Minimal Supersymmetric Standard Model, in the presence of light stops.
We show that, in previously unexplored regions of parameter space, the order
parameter $v(T_c)/T_c$ can become significantly larger than one, for values of
the Higgs and supersymmetric particle masses consistent with the present
experimental bounds. This implies that baryon number can be efficiently
generated at the electroweak phase transition. As a by-product of this study,
we present an analysis of the problem of colour breaking minima at zero and
finite temperature, and we use it to investigate the region of parameter space
preferred by the best fit to the present precision electroweak measurement
data, in which the left-handed stops are much heavier than the right-handed
ones.


title: Hadronic Correlators and Condensate Fluctuations in QCD Vacuum

abstract:
  Phenomenological results of equal time, point to point spatial correlation
functions of hadronic currents are used to deduce the structure of the QCD
vacuum. It is found that a model with only quark condensate is not adequate to
explain the observations. Inclusion of condensate fluctuations (explicit four
point structure in the vacuum) leads to excellent overall agreement with the
phenomenological curves and parameters in various channels.


title: The Context of High Energy QCD Spin Physics

abstract:
  Opening talk presented at the Adriatico Research Conference -- Trends in
Collider Spin Physics and at the RIKEN Symposium -- Spin Structure of the
Nucleon.
  We present an overview of the opportunities to explore QCD at a very high
energy polarized hadron collider. We review connections to low energy flavor
physics, transverse spin in QCD and higher twist. It is clear that polarized
colliders will provide a wealth of new information about the behavior of quarks
and gluons inside hadrons complementing that available from lepton scattering
and other more familiar probes of hadron structure.


title: QCD Corrections to SUSY Higgs Production: The Role of Squark Loops

abstract:
  We calculate the two-loop QCD corrections to the production of the neutral
supersymmetric Higgs bosons via the gluon fusion mechanism at hadron colliders,
including the contributions of squark loops. To a good approximation, these
additional contributions lead to the same QCD corrections as in the case where
only top and bottom quark loops are taken into account. The QCD corrections are
large and increase the Higgs production cross sections significantly.


title: Feynman integral in regularized non-relativistic quantum electrodynamics

abstract:
  We express the unitary time evolution in non-relativistic regularized quantum
electrodynamics at zero and positive temperature by a Feynman integral defined
in terms of a complex Brownian motion. An average over the quantum
electromagnetic field determines the form of the quantum mechanics in an
environment of a quantum black body radiation. In this non-perturbative
formulation of quantum electrodynamics we prove the existence of the classical
limit $\hbar \rightarrow 0$.We estimate an error to some approximations
commonly applied in quantum radiation theory.


title: Relativistic and Neutrino Mass Effects in Partial Muon Capture

abstract:
  The characteristics of the partial nuclear muon capture with massive
left-handed Dirac neutrino and relativistic component of the muon wave function
have been derived. The multipole amplitudes are given as a function of neutrino
mass parameter and reduced nuclear matrix elements which are modified by the
small component of the muon wave function. As an example, the capture rate,
asymmetry and polarization of recoil nuclei are investigated in terms of these
multipole amplitudes.


title:
Two-body Cabibbo-suppressed Decays of Charmed Baryons into Vector Mesons
  and into Photons

abstract:
  The heavy quark effective theory and the factorization approximation are used
to treat the Cabibbo-suppressed decays of charmed baryons to vector mesons,
$\Lambda_C\rightarrow p{\rho^0}, p\omega$,
$\Xi_C^{+,0}\rightarrow\Sigma^{+,0}\phi, \Sigma^{+,0}{\rho^0},
\Sigma^{+,0}\omega$ and $\Xi_C^{0}\rightarrow\Lambda\phi, \Lambda\rho,
\Lambda\omega$. The input from two recent experimental results on $\Lambda_C$
decays allows the estimation of the branching ratios for these modes, which
turn out to be between $10^{-4}$ and $10^{-3}$. The long distance contribution
of these transitions via vector meson dominance to the radiative weak processes
$\Lambda_C\rightarrow p\gamma$, $\Xi_C\rightarrow\Sigma\gamma$ and
$\Xi_C^0\rightarrow\Lambda\gamma$ leads to quite small branching ratios,
$10^{-6}-10^{-9}$; the larger value holds if a sum rule between the coupling
constants of the vector mesons is broken.


title: The hidden Higgs model at the NLC

abstract:
  We investigate the influence of massless scalar singlets on Higgs signals at
the NLC. An exclusion bound is presented which restricts large regions of the
parameter space but on the other hand implies that for strong interactions
between the Higgs boson and the singlet fields of the hidden sector, detection
of such a non standard Higgs signal can become impossible.


title: Higher-twist quark-mass contributions to deep-inelastic scattering

abstract:
  In this letter we extend the factorization procedure of the deep-inelastic
hadron tensor, proposed by Qiu, to include non-zero quark masses. The manifest
gauge invariance of both soft and hard parts is preserved. Using a so-called
spurion to generate the quark-mass terms, the simple parton-model
interpretation is also kept. The calculation of the deep-inelastic
transverse-spin structure function $g_2$ is used to illustrate the algorithm.


title: Relativistic Coulomb Problem: Analytic Upper Bounds on Energy Levels

abstract:
  The spinless relativistic Coulomb problem is the bound-state problem for the
spinless Salpeter equation (a standard approximation to the Bethe--Salpeter
formalism as well as the most simple generalization of the nonrelativistic
Schr\"odinger formalism towards incorporation of relativistic effects) with the
Coulomb interaction potential (the static limit of the exchange of some
massless bosons, as present in unbroken gauge theories). The nonlocal nature of
the Hamiltonian encountered here, however, renders extremely difficult to
obtain rigorous analytic statements on the corresponding solutions. In view of
this rather unsatisfactory state of affairs, we derive (sets of) analytic upper
bounds on the involved energy eigenvalues.


title: Real Oscillations of Virtual Neutrinos

abstract:
  We study the conditions for neutrino oscillations in a field theoretical
approach by taking into account that only the neutrino production and detection
processes, which are localized in space around the coordinates $\vec{x}_P$ and
$\vec{x}_D$, respectively, can be manipulated. In this sense the neutrinos
whose oscillations are investigated appear as virtual lines connecting
production with detection in the total Feynman graph and all neutrino fields or
states to be found in the discussion are mass eigenfields or eigenstates. We
perform a thorough examination of the integral over the spatial components of
the inner neutrino momentum and show that in the asymptotic limit $L=|\vec{x}_D
- \vec{x}_P| \rightarrow \infty$ the virtual neutrinos become ``real'' and
under certain conditions the usual picture of neutrino oscillations emerges
without ambiguities.


title: Probing Lepton Flavor Violation at Future Colliders

abstract:
  Supersymmetric theories with significant lepton flavor violation have
$\tilde{e}$ and $\tilde{\mu}$ nearly degenerate. In this case, pair production
of $\tilde{e}^+ \tilde{e}^-$ and $\tilde{\mu}^+ \tilde{\mu}^-$ at LEPII and at
the Next Linear Collider leads to the phenomenon of slepton oscillations, which
is analogous to neutrino oscillations. The reach in $\Delta m^2$ and $\sin^2 2
\theta$ gives a probe of lepton flavor violation which is significantly more
powerful than the current bounds from rare processes, such as $\mu \to
e\gamma$. Polarizable $e^-$ beams and the $e^-e^-$ mode at the NLC are found to
be promising options.


title: The Top Quark and other Fermion Masses

abstract:
  Recent developments on approaches to the quark lepton mass problem are
reviewed. In particular we discuss dynamical calculations of the top quark mass
at (a) the infrared quasifixed point of the Minimal Supersymmetric Standard
Model renormalisation group equations, and (b) a strongly first order critical
point of the Standard Model effective potential. The phenomenology of symmetric
mass matrix ans\"{a}tze with texture zeros at the unification scale is also
considered. The underlying chiral symmetry presumed responsible for the fermion
mass hierarchy is discussed, with particular reference to superstring based
models.


title:
Simultaneous Search for Two Higgs Bosons of Minimal Supersymmetry at the
  LHC

abstract:
  The prospects of detecting the CP-odd Higgs pseudoscalar ($A$) in the minimal
supersymmetric model via its decay into a $Z$ boson and the lighter CP-even
Higgs scalar ($h$) at the CERN Large Hadron Collider are investigated. The
final state of $Z \to l^+l^-$ and $h \to b\bar{b}$, may provide a promising way
to simultaneously detect the $A$ and the $h$. The compact muon solenoid
detector performance is adopted for a realistic study of observability. In this
discovery channel, the masses of the $h$ and the $A$ can be reconstructed. The
impact of supersymmetric decay modes is considered.


title:
Symmetry Restoration in Gauge Boson Wave Packet Collisions in
  Yang-Mills-Higgs Theory

abstract:
  We investigate the restoration of spontaneously broken gauge symmetry in
collisions of gauge boson wave packets in the SU(2) Higgs model.


title:
Yukawa Corrections to Top Quark Production at the LHC in Two-
  Higgs-Doublet Models

abstract:
  The O(alpha m_t^2/m_W^2) corrections to top quark pair production by
gluon-gluon fusion at the LHC are calculated in two-Higgs-doublet models. We
find that the correction to the cross-section can exceed about -10% for certain
parameter values.


title: Could there be a Fourth Generation of Quarks Without More Leptons?

abstract:
  We investigate the possibility of adding a fourth generation of quarks. We
also extend the Standard Model gauge group by adding another SU(N) component.
In order to cancel the contributions of the fourth generation of quarks to the
gauge anomalies we must add a generation of fermions coupling to the SU(N)
group. This model has many features similar to the Standard Model and, for
example, includes a natural generalisation of the Standard Model charge
quantisation rule. We discuss the phenomenology of this model and, in
particular, show that the infrared quasi-fixed point values of the Yukawa
coupling constants put upper limits on the new quark masses close to the
present experimental lower bounds.


title: Need for Two Vectorlike Families in SUSY Composite Models

abstract:
  Within the context of a viable and economical SUSY preon model, two
vector--like families $Q_{L,R} = (U,D,N,E)_{L,R}$ and $Q^\prime_{L,R} =
(U^\prime,D^\prime,N^\prime,E^\prime)_{L,R}$ with masses of order 1 TeV, one of
which is a doublet of $SU(2)_L$ and the other a doublet of $SU(2)_R$, have been
predicted to exist together with the three observed chiral families. The
existence of these two vector--like families turns out to be crucial especially
for an explanation of the inter--family mass--hierarchy and therefore for the
SUSY preon model itself. This paper is devoted to a detailed study of the
expected masses, mixings and decay modes of the vector--like fermions.
Including QCD renormalization--effects, the masses of the vector--like quarks
are expected to lie in the range of 500 GeV to about 2.5 TeV, while those of
the vector--like leptons are expected to be in the range of 200 GeV to 1 TeV.


title:
GENTLE/4fan - A package of Fortran programs for the description of e+ e-
  annihilation into four fermions

abstract:
  We describe the program package gentle/4fan, which consists of the Fortran
codes gentle\_4fan.f, 4fan.f, and gentle\_nc\_qed.f and is devoted to the
description of e+ e- annihilation into four fermions. The codes are based on
the semi-analytical approach. Initial state QED corrections are taken into
account. The program versions, which are described here were used in the 1995
workshop `Physics at LEP~2'.


title: Colour-octet NLO QCD corrections to hadronic $\chi_J$ decays

abstract:
  In this paper we present a complete next-to-leading order QCD calculation of
the $\chi_J$ ($^3P_J\; ;J=0,1,2$) hadronic decay width. We include the NLO
colour-octet contribution, as defined in the Bodwin, Braaten and Lepage
formalism. We extract an estimate of the colour-octet parameter \height\ from
the charmonium decay data.


title:
Main phenomenological features of the spontaneous CP violation in SU(3)
  x U(1) models

abstract:
  We analyze the phenomenological consequences of assuming spontaneous CP
violation in an SU(3) x U(1) model with three Higgs triplets and one sextuplet.
After the identification of the relevant physical scalars, we estimate the
contributions to the parameters $\Delta m_K$, $\epsilon$ and $\epsilon'$ coming
from the Higgs-fermion couplings.


title: Supersymmetric three-body decays of the Top Quark in the MSSM

abstract:
  We survey all possible supersymmetric three-body decays of the top quark in
the framework of the MSSM and present detailed numerical analyses of the most
relevant cases. Although the two-body channels are generally dominant, it is
not inconceivable that some or all of our most favourite two-body SUSY
candidates could be suppressed. In this event there is still the possibility
that some of the available three-body SUSY modes might exhibit a substantial
branching fraction and/or carry exotic signatures that would facilitate their
identification. Furthermore, in view of the projected inclusive measurement of
the top-quark width $\Gamma_t$ in future colliders, one should have at one's
disposal the full second order correction (electroweak and strong) to the value
of that parameter in the MSSM. Our analysis confirms that some supersymmetric
three-body decays could be relevant and thus contribute to $\Gamma_t$ at a
level comparable to the largest one loop supersymmetric effects on two-body
modes recently computed in the literature.


title:
Top-squark mixing effects in the supersymmetric electroweak corrections
  to top quark production at the Tevatron

abstract:
  Taking into account the mixing effects between left- and right-handed
top-squarks, we calculate the genuine supersymmetric eletroweak correction to
top quark production at the Tevatron in the minimal supersymmetric model. The
analytic expressions of the corrections to both the parton level cross section
and the total hadronic cross section are presented. Some numerical examples are
also given to show the size of the corrections.


title: Resonant neutrino spin-flavor precession and supernova shock revival

abstract:
  A new mechanism of supernova shock revival is proposed, which involves
resonant spin--flavor precession of neutrinos with a transition magnetic moment
in the magnetic field of the supernova. The mechanism can be operative in
supernovae for transition magnetic moments as small as $10^{-14}\mu_B$ provided
the neutrino mass squared difference is in the range $\Delta m^2 \sim (3 \;{\rm
eV})^2-(600 \;{\rm eV})^2$. It is shown that this mechanism can increase the
neutrino--induced shock reheating energy by about 60\%.


title:
Form factor $\pi^0\to \gamma^* +\gamma^*$ at different photon
  virtualities

abstract:
  The $\pi^0 \gamma\gamma$ vertex for virtual photons of squared masses $q_1^2$
and $q_2^2$ plays a vital r\^ole in several physical processes; for example for
$q_1^2<0$, $q_2^2<0$, in the two-photon physics reaction $e^+ e^-\to e^+ e^-
\pi^0$, and for $q_1^2>0$, $q_2^2>0$, in the annihilation process $e^+ e^-\to
\pi^0 l^+ l^-$. It is also of interest because of its link to the axial
anomaly. We suggest a new approach to this problem. We have obtained a closed
analytic expression for the vertex in the limit in which at least one of
$|q_1^2|$ and $|q_2^2|$ is large for arbitrary fixed values of the ratio
$q_1^2/q_2^2$. We compare our results with those obtained previously by Brodsky
and Lepage. It should be straightforward to test our predictions
experimentally.


title: Non-minimal neutral Higgs bosons at LEP2

abstract:
  We study the phenomenology of the neutral Higgs sector of a non-SUSY
non-minimal Standard Model. Models with more than one Higgs doublet are
possible, and may contain neutral Higgs scalars with branching ratios
significantly different to those of the Minimal Standard Model Higgs boson. We
show how these differences may be exploited at LEP2 in order to distinguish the
non-minimal Standard Model from the minimal version.


title: Do Sum Rules in Deep Inelastic Scattering Follow From QCD?

abstract:
  We consider restrictions imposed on the electromagnetic and weak current
operators by Poincare invariance and show that some assumptions used in
deriving the sum rules in deep inelastic scattering (DIS) have no physical
ground. In particular there is no ground to neglect the contribution of
nonperturbative effects to these operators, even in the Bjorken limit.
Therefore the conclusion that the sum rules in DIS unambiguously follow from
QCD is not substantiated.


title: Heavy Baryons in SU(2) $\times$ SU(6)

abstract:
  The spectrum of baryons containing heavy quarks of one flavor is described in
terms of representations of the group SU(2) X SU(6), where the two factor
groups refer to spin rotations of the heavy quarks and spin-flavor rotations of
the light quarks, respectively. This symmetry has a natural interpretation in
the heavy quark limit. We exhibit the decomposition of baryon mass operators
under this symmetry and compare to experimental results. We discuss the
relation of this analysis to that of large-N_c QCD as well as four-flavor
SU(8), and indicate the generalization of this work to other properties of
heavy baryons.


title:
Order 1/m_b^3 corrections to B\to X_c\ell\bar\nu decay and their
  implication for the measurement of \bar\Lambda and \lambda_1

abstract:
  We compute the order 1/m_b^3 nonperturbative contributions to the inclusive
differential B\to X_c\ell\bar\nu decay rate. They are parametrized by the
expectation values of two local and four nonlocal dimension-six operators. We
use our results to estimate part of the theoretical uncertainties in the
extraction of matrix elements \bar\Lambda and \lambda_1 from the lepton
spectrum in the inclusive semileptonic B decay and find them to be very large.
We also compute the 1/m_b^3 corrections to the moments of the hadronic
invariant mass spectrum in this decay, and combine them with the extracted
values of \bar\Lambda and \lambda_1 to put an upper bound on the branching
fraction Br(B\to D^{**}\ell\bar\nu).


title: Heavy Baryon Masses in the $1/m_Q$ and $1/N_c$ Expansions

abstract:
  The masses of baryons containing a single heavy quark are studied in a
combined expansion in $1/m_Q$, $1/N_c$ and $SU(3)$ flavor symmetry breaking.
Heavy quark baryon mass splittings are related to mass splittings of the octet
and decuplet baryons. The $\Sigma_c^*$, $\Xi_c^\prime$ and $\Omega_c^*$ are
predicted to the level of a few MeV. A number of bottom baryon mass splittings
are predicted very accurately.


title:
On the Resummation of $\alpha \ln^2 x$ Terms for Non-Singlet Structure
  Functions in QED and QCD

abstract:
  The resummation of $O(\alpha^{l+1} \ln^{2l} x)$ terms in the evolution
kernels of non--singlet combinations of structure functions is investigated for
both QED abd QCD. Numerical results are presented for unpolarized and polarized
structure functions.


title:
Nucleosynthesis constraints on heavy tau-neutrino in the presence of
  annihilations to majorons

abstract:
  We show that in the presence of sufficiently strong $\nu_\tau$ annihilations
to majorons, primordial nucleosynthesis constraints can not rule out any values
of the $\nu_\tau$ mass up the present laboratory limit.


title: Failure of Local Duality in Inclusive Non-Leptonic Heavy Flavour

abstract:
  We argue that there is strong experimental evidence in the data of b- and
c-decays that the pattern of power suppressed corrections predicted by the
short distance expansion, the heavy quark effective theory and the assumption
of local duality is not correct for the non-leptonic inclusive widths. The data
indicate instead the presence of 1/m corrections that should be absent in the
above theoretical framework. These corrections can be simply described by
replacing the heavy quark mass by the mass of the decaying hadron in the m^5
factor in front of all the non-leptonic widths.


title: On the Spectrum of Scalar-Scalar Bound States

abstract:
  A new, exactly solvable, Barbieri-Remiddi like equation for bound states of
two scalar constituents interacting with massless vector particles is
presented, both for stable and unstable particles. With the help of this
equation the bound state spectrum is calculated to O(\alpha^4) for a SU(N)
nonabelian gauge theory. The result for the abelian case reproduces the known
result from the Foldy-Wouthuysen calculation. It is shown how different graphs
as in the fermionic theory contribute to the spectrum to this order.
Furthermore the bound state correction to the decay width for a weakly decaying
system is calculated. This result is equal to its fermionic counterpart. Thus
the theorem on bound state corrections for weakly decaying particles,
formulated previously for fermions only, has been extended to the scalar
theory.


title: Quarks and Gluons in Nucleon Polarized Structure Functions

abstract:
  We study the available data in polarized e-p deep inelastic scattering to
test two different solutions to the so called spin crisis: one of them based on
the axial gluon anomaly and consistent with the Bjorken sum rule and another
one, where the defects in the spin sum rules and in the Gottfried sum rule are
related. In this case a defect is also expected for the Bjorken sum rule.
Experimental data, especially the very recent SLAC E154, favour the first
solution and demand a gluon polarization $\Delta G = 2.25 \pm 1.39$.


title: The $m^4 \ln m\,$ Contribution to the Nucleon Mass in CHPT

abstract:
  In CHPT the hadron masses obtain loop corrections from the pseudoscalar
mesons which are identified with the Goldstone bosons of broken chiral
symmetry. An expansion of the baryon mass in the quark masses therefore
includes non-analytic terms. We calculate the nucleon mass in the one-loop
approximation to order $m^4 \sim m_q^2$. We compare the result in the
relativistic and in the heavy mass formulation of the theory and derive
matching relations between corresponding low-energy constants. We calculate the
pion-nucleon loop in old-fashioned perturbation theory and find a contribution
to the $m^4 \ln m$ term from an intermediate state which does not occur in the
heavy baryon theory.


title: Multigluon Tree Amplitudes and Self-Duality Equation

abstract:
  A generating function for a class of multigluon amplitudes is constructed as
a particular solution of the self-duality equation.


title: New Algorithm to Investigate Neural Networks

abstract:
  Random cost simulations were introduced as a method to investigate
optimization problems in systems with conflicting constraints. Here I study the
approach in connection with the training of a feed-forward multilayer
perceptron, as used in high energy physics applications. It is suggested to use
random cost simulations for generating a set of selected configurations. On
each of those final minimization may then be performed by a standard algorithm.
For the training example at hand many almost degenerate local minima are thus
found. Some effort is spend to discuss whether they lead to equivalent
classifications of the data.


title: Charm and Bottom Semileptonic Decays

abstract:
  We review the present status of theoretical attempts to calculate the
semileptonic charm and bottom decays and then present a calculation of these
decays in the light--front frame at the kinematic point $q^2=0$. This allows us
to evaluate the form factors at the same value of $q^2$, even though the
allowed kinematic ranges for charm and bottom decays are very different. Also,
at this kinematic point the decay is given in terms of only one form factor
$A_{0}(0)$. For the ratio of the decay rates given by the E653 collaboration we
show that the determination of the ratio of the Cabibbo--Kobayashi--Maskawa
(CKM) matrix elements is consistent with that obtained from the unitarity
constraint. At present, though, the unitarity method still has greater
accuracy. Since comparisons of the semileptonic decays into $\rho$ and either
electrons or muons will be available soon from the E791 Fermilab experiment, we
also look at the massive muon case. We show that for a range of $q^2$ the
$SU(3)_F$ symmetry breaking is small even though the contributions of the
various helicity amplitudes becomes more complicated. For $B$ decays, the decay
$B \rightarrow K^{*} \ell \bar{\ell}$ at $q^2=0$ involves an extra form factor
coming from the photon contribution and so is not amenable to the same kind of
analysis, leaving only the decay $B \rightarrow K^{*}\nu \bar{\nu}$ as a
possibility. As the mass of the decaying particle increases we note that the
$SU(3)$ symmetry becomes badly broken at $q^2=0$.


title:
Small x parton distributions and initial conditions in ultrarelativistic
  nuclear collisions

abstract:
  At the colliders RHIC and LHC, nuclei at the ultrarelativistic energies of
$100$ GeV/A and $2.7$ TeV/A will be smashed together with the hope of creating
an elusive and short-lived state of matter called the quark gluon plasma. The
initial conditions which determine the dynamical evolution of the quark gluon
matter formed in the central region after the collision depend crucially on the
small $x$ component of the nuclear wavefunction before the collision. In this
comment, we discuss recent work which argues that, for large nuclei, weak
coupling techniques in QCD can be used to calculate the distribution of these
small $x$, or wee, partons. The ramifications of this approach for the dynamics
of heavy ion collisions and the various signatures of a quark gluon phase of
matter are discussed.


title: Parton model sum rules

abstract:
  This review article discusses the experimental and theoretical status of
various Parton Model sum rules. The basis of the sum rules in perturbative QCD
is discussed. Their use in extracting the value of the strong coupling constant
is evaluated and the failure of the naive version of some of these rules is
assessed.


title:
New Constraints from Electric Dipole Moments on Parameters of the
  Supersymmetric SO(10) Model

abstract:
  We calculate the chromoelectric dipole moment (CEDM) of d- and s-quark in the
supersymmetric SO(10) model. CEDM is more efficient than quark electric dipole
moment (EDM), in inducing the neutron EDM. New, strict constraints on
parameters of the supersymmetric SO(10) model follow in this way from the
neutron dipole moment experiments. As strict bounds are derived from the upper
limits on the dipole moment of odd isotope of mercury.


title:
Is the Model of Spontaneous CP-violation in the Higgs Sector Consistent
  with Experiment?

abstract:
  At natural values of parameters of the model dicussed, the contribution of
the chromoelectric dipole moment of the s-quark to the neutron electric dipole
moment (EDM) exceeds considerably the experimental upper limit for the neutron
EDM. As strict bounds on the parameters of the model are derived from the
atomic experiment with odd isotope of mercury.


title:
Induced Light-Quark Yukawa Couplings as a probe of Low-Energy Dynamics
  in QCD

abstract:
  We examine the heavy-quark-induced Yukawa interaction between light quarks
and a light Higgs field, which is facilitated in the chiral limit by the
dynamical mass of light quarks anticipated from the chiral-noninvariance of the
QCD vacuum. A low-energy estimate of the strong coupling near unity can be
obtained from a comparison of the explicit perturbative calculation of the
induced Yukawa interaction at zero momentum to a Higgs-low-energy theorem
prediction for the same interaction.


title:
Violations of universality in a vectorlike extension of the standard
  model

abstract:
  Violations of universality of couplings in a vectorlike extension of the
standard model with three heavy mirror fermion families are considered. The
recently observed discrepancies between experiments and the standard model in
the hadronic branching fractions $R_b$ and $R_c$ of the Z-boson are explained
by the mixing of fermions with their mirror fermion partners.


title: Partonic Structure of the Pomeron

abstract:
  The first measurement of diffractive processes in deep inelastic scattering
at the HERA collider is analysed in terms of a "soft" pomeron exchange model.
The partonic structure of the pomeron which emerges in this picture is
determined using the QCD parton model. The important role of the gluonic
component in the partonic interpretation of the data is particularly
emphasized.


title: All-order Finiteness in N=1 SYM Theories: Criteria and Applications

abstract:
  As a motivation, we first recall the possible connection of electric-magnetic
duality to finiteness in N=1 super-Yang-Mills theories (SYM). Then, we present
the criterion for all-order finiteness (i.e., vanishing of the beta-functions
at all orders) in N=1 SYM. Finally, we apply this finiteness criterion to an
SU(5) SGUT. The latter turns out to be all-order finite if one imposes
additional symmetries.


title: Scattering Lengths and Medium and High Energy $\pi\pi$ Scattering

abstract:
  Medium and high energy absorptive parts contribute to dispersive expressions
for D- wave scattering lengths, $a^0_2$ and $a^2_2$. For the model employed by
Basdevant, Frogatt and Peterson we find the D- wave driving term contributions
to the D- wave scattering lengths are $1.8\cdot 10^{-4}$ to $a^0_2$ and
$0.4\cdot 10^{-4}$ to $a^2_2$, roughly $10\%$ and $30\%$ of their respective
  central experimental values. Inequivalent sets of sum rules are used as a
compelling test of the consistency of the model for which crossing symmetry is
not guaranteed. Results for the F- wave scattering length $a^1_3$ are
presented, completing the recent Roy equation analysis of \pipi scattering in
the range for $a^0_0$ favored by standard chiral perturbation theory.


title: A Quasi-maximal mixing ansatz for neutrino oscillations

abstract:
  Inspired by the atmospheric multi-GeV neutrino data, we consider neutrino
flavor mixing matrices which are maximal in a $2\times 2$ subsector. This
condition is a strong restriction: the full matrix including complex phases
depends essentially on one parameter. The survival probability is an universal
function of $L/E$, independent of generation, in the region of interest for the
accelerator and atmospheric experiments. It is possible with the solar neutrino
data alone to recover completely the mixing matrix suggested by the atmospheric
data. The results are not essentially modified by the MSW effect in the solar
data. Consequences for future experiments are considered.


title:
The solution to the strong CP problem at the BCS level of chiral
  rotations

abstract:
  We briefly review the cases of forced and spontaneous chiral symmetry
breaking. In particular the chiral condensate of q anti-q pairs is parametrized
with two angles, phi which measures the chiral condensation, and theta which
measures the chiral rotation. The strong CP problem arises when it is assumed
that the current quark masses of the Standard Model, have a theta phase that
differs from the phase induced by the instanton term wich is originated in the
QCD sector of the Standard Model. We show how chiral symmetry breaking may
solve the strong CP problem at the BCS level. We show variationally that the
physical vacuum is CP conserving and therefore the interplay of the instanton
and the current mass terms cannot produce any strong CP violation. We also
study the possible effect of theta in weak interactions, and conclude that it
does not produce weak CP.


title: QCD Selection Rules in Polarized Hadron Collisions

abstract:
  Plans are underway to measure spin asymmetries at large momentum transfer in
hadron hadron collisions at RHIC and elsewhere. Proposals have focused on
measuring quark transversity and quark and gluon helicity distributions in the
nucleon. These experiments will also provide a strong and simple test of
perturbative QCD, namely that ${\cal A}_{TT}/{\cal A}_{LL}\ll 1$ in
$pp\rightarrow 2\, {\rm jets} +X$ and several related processes, whereas ${\cal
A}_{TT}/{\cal A}_{LL}\sim 1$ in Drell-Yan production of muon pairs. The
prediction tests the helicity, twist and chirality selection rules of
perturbative QCD that form the foundation for the analysis of spin dependent
hard processes. We estimate the ratio ${\cal A}_{TT}/{\cal A}_{LL}$ numerically
for polarized protons at RHIC.


title:
Search of Stop, Sbottom, and Stau at an $e^+e^-$ Linear Collider with
  $\sqrt{s}$ = 0.5 - 2 TeV

abstract:
  We discuss pair production and decays of stops, sbottoms, and staus in
$e^+e^-$ annihilation in the energy range $\sqrt{s}$ = 500 GeV to 2 TeV. We
present numerical predictions within the Minimal Supersymmetric Standard Model
for cross sections and decay rates. We study the stop discovery potential for
$\sqrt{s}$ = 500 GeV and $10~\fb^{-1}$ integrated luminosity with full
statistics background simulation.


title: A dark matter solution from the supersymmetric axion model

abstract:
  We study the effect of the late decaying saxino (the scalar superpartner of
the axion) and find out that there is a possible dark matter solution from a
class of supersymmetric extensions of the invisible axion model. In this class
of models, the saxino which decays into two axions acts as the late decaying
particle which reconciles the cold dark matter model with high values of the
Hubble constant. Recent observations of the Hubble constant are converging to
$H_0=70\!-\!80\,{\rm km}\,{\rm sec}^{-1}\,{\rm Mpc}^{-1}$, which would be
inconsistent with the standard mixed dark matter model. This class of models
provides a plausible framework for the alternative cold dark matter plus late
decaying particle model, with the interesting possibility that both cold dark
matter and the extra radiation consist of axion.


title:
QCD and Yukawa corrections to single-top-quark production via q qbar ->
  t bbar

abstract:
  We calculate the O(alpha_s) and O(alpha_W m_t^2/M_W^2) corrections to the
production of a single top quark via the weak process q qbar -> t bbar at the
Fermilab Tevatron and the CERN Large Hadron Collider. An accurate calculation
of the cross section is necessary in order to extract |V_tb| from experiment.


title:
Effects of Screening on Quark-Antiquark Cross Sections in Quark-Gluon
  Plasma

abstract:
  Lowest-order cross sections for $q\bar q$ production and annihilation can be
approximately corrected for higher-order QCD effects by using a corrective
$K$-factor. For energies where quark masses cannot be ignored, the $K$-factor
is dominated by the wave function distortion arising from the initial- or
final-state interaction between the quark and the antiquark. We evaluate this
$K$-factor for $q \bar q$ production and annihilation in a quark-gluon plasma
by taking into account the effects of Debye screening through a color-Yukawa
potential. We present the corrective $K$-factor as a function of dimensionless
parameters which may find applications in other systems involving attractive or
repulsive Yukawa interactions. Prominent peaks of the $K$-factor occur for an
attractive $q$-$\bar q$ color-Yukawa interaction with Debye screening lengths
of 0.835 and 3.23 times the Bohr radius, corresponding to two lowest $s$-wave
$q\bar q$ bound states moving into the continuum to become $q\bar q$ resonances
as the Debye screening length decreases. These resonances, especially the
$c\bar c$ and the $b \bar b$ resonances, may be utilized to search for the
quark-gluon plasma by studying the systematics of the temperature dependence of
heavy-quark pair production just above the threshold.


title: Average Kinetic Energy of Heavy Quark in Semileptonic B Decay

abstract:
  Within the ACCMM model the average kinetic energy of heavy quark in a
heavy-light meson is calculated as $\langle {\bf p}^2 \rangle = {3 \over 2}
{p_{_F}}^2$, solely from the fact that the Gaussian momentum probability
distribution has been taken in the ACCMM model. Therefore, the Fermi momentum
parameter $p_{_F}$ of the ACCMM model is not a truly free parameter, but is
closely related to the average kinetic energy of heavy quark, which is
theoretically calculable in principle. In this context, we determine $p_{_F}$
by comparing the theoretical prediction of the ACCMM model with the model
independent lepton energy spectrum of $B \rightarrow e \nu X$ from the recent
CLEO analysis, and find that $p_{_F}=0.54~\pm~^{0.16}_{0.15}$ GeV. We also
calculate $p_{_F}$ in the relativistic quark model by applying the quantum
mechanical variational method, and obtained $p_{_F}=0.5\sim 0.6$ GeV. We show
the correspondences between the relativistic quark model and the heavy quark
effective theory. We then clarify the importance of the value of $p_{_F}$ in
the determination of $|V_{ub}/V_{cb}|$.


title:
Production of pseudovector heavy quarkonia by virtual Z boson in
  electron-positron collisions

abstract:
  It is shown that $BR(\chi_{b1}(1P)\rightarrow Z\rightarrow e^+e^-)\simeq
3.3\cdot 10^{-7}$, $BR(\chi_{b1}(2P)\rightarrow Z\rightarrow e^+e^-)\simeq
4.1\cdot 10^{-7}$ and $BR(\chi_{c1}(1P)\rightarrow Z\rightarrow e^+e^-)\simeq
10^{-8}$ that give a good chance to search for the direct production of
pseudovector $^3P_1$ heavy quarkonia in $e^+e^-$ collisions ($e^+e^-\rightarrow
Z\rightarrow ^3P_1$) even at current facilities not to mention $b$ and $c-\tau$
factories. Leading radiative corrections to annihilation of quarkonia in QCD
are discussed.


title: Integrating out Gluons in Flow Equations

abstract:
  We present an exact nonperturbative flow equation for the average action for
quarks which incorporates the effects of gluon fluctuations. With suitable
truncations this allows one to compute effective multiquark interactions in
dependence on an infrared scale $k$. Our method amounts to integrating out the
gluons with momenta larger than $k$.


title: Study of Long Distance Contributions to $K\to n\pi\nu\bar{\nu}$

abstract:
  We calculate long distance contributions to $K\to\pi\nu\bar{\nu}\,,\
\pi\pi\nu\bar{\nu}$, and $\pi\pi\pi\nu\bar{\nu}$ modes within the framework of
chiral perturbation theory. We find that these contributions to decay rates of
$K\to \pi\nu\bar{\nu}$ and $K\to \pi\pi\nu\bar{\nu}$ in the chiral logarithmic
approximation are at least seven orders of magnitude suppressed relative to
those from the short distance parts. The long distance effects in this class of
decays are therefore negligible.


title: Baryogenesis and lepton number violation

abstract:
  The cosmological baryon asymmetry can be explained by the nonperturbative
electroweak reprocessing of a lepton asymmetry generated in the
out-of-equilibrium decay of heavy right-handed Majorana neutrinos. We analyze
this mechanism in detail in the framework of a SO(10)-subgroup. We take three
right-handed neutrinos into account and discuss physical neutrino mass
matrices.


title: Quantum Statistical Parton Distributions and the Spin Crisis

abstract:
  Quantum statistical distributions for the partons provide a fair description
of deep inelastic scattering data at $Q^2 = 3$ and $10 (GeV/c)^2$. The study of
the polarized structure functions seems to suggest an alternative possible
solution of the {\it spin crisis} based on the Pauli principle. In this scheme,
in fact, the defects of the Gottfried sum rule and Ellis--Jaffe sum rule for
proton, result strongly connected. This possibility finds particular evidence
from the phenomenological observation that the relation $\Delta u = 2 \tilde{F}
+ u - d -1$ seems well satisfied by parton distributions.


title: Bubble collisions in Abelian gauge theories and the geodesic rule

abstract:
  In an Abelian gauge symmetry, spontaneously broken at a first order phase
transition, we investigate the evolution of two and three bubbles of the broken
symmetry phase. The full field equations are evolved and we concentrate in
particular on gauge invariant quantities, such as the magnetic field and the
integral around a closed loop of the phase gradient. An intriguing feature
emerges, namely, the geodesic rule, commonly used in numerical simulations to
determine the density of defects formed is shown not to hold in a number of
circumstances. It appears to be a function of the initial separation of the
bubbles, and the coupling strength of the gauge field. The reason for the
breakdown is that in the collision region the radial mode {\it can} be excited
and {\it often} oscillates about its symmetry restoring value rather than
settling to its broken symmetry value. This can lead to extra windings being
induced in these regions, hence extra defects (anti-defects) being formed.


title: Weak-Scale Supersymmetry: Theory and Practice

abstract:
  These lectures contain an introduction to the theory and practice of
weak-scale supersymmetry. They begin with a discussion of the hierarchy problem
and the motivation for weak-scale supersymmetry. They continue by developing
the coset approach to superfields. They use superfield techniques to construct
the minimal supersymmetric version of the standard model and to discuss soft
supersymmetry breaking and its implications. The lectures end with a brief
survey of expectations for future collider experiments.


title: Weak Phases From B Decays to Kaons and Charged Pions

abstract:
  Phases of elements of the Cabibbo-Kobayashi-Maskawa (CKM) matrix can be
obtained using decays of $B$ mesons to $\pi^+ \pi^-$, $\pi^\pm K^\mp$, and
$\pi^+ K^0$ or $\pi^- \overline{K}^0$. For $B^0~{\rm or}~ \overline{B}^0 \to
\pi^+ \pi^-$, one identifies the flavor of the neutral $B$ meson at time of
production and studies the time-dependence of the decay rate. The other
processes are self-tagging and only their rates need be measured. By assuming
flavor SU(3) symmetry and first-order SU(3) breaking, one can separately
determine the phases $\gamma \equiv {\rm Arg}~V_{ub}^*$ and $\alpha = \pi -
\beta - \gamma$, where $\beta \equiv {\rm Arg}~V_{td}^*$. Special cases include
the vanishing of strong interaction phase differences between amplitudes, the
possibility of recovering partial information when $\pi^+ \pi^-$ and $\pi^\pm
K^\mp$ decays cannot be distinguished from one another, and the use of a
correlation between $\gamma$ and $\alpha$ in the region of allowed parameters.


title: On the Resummation of Singular Distributions in QCD Hard Scattering

abstract:
  We discuss the resummation of distributions that are singular at the elastic
limit of partonic phase space (partonic threshold) in QCD hard-scattering cross
sections, such as heavy quark production. We show how nonleading soft
logarithms exponentiate in a manner that depends on the color structure within
the underlying hard scattering. This result generalizes the resummation of
threshold singularities for the Drell-Yan process, in which the hard scattering
proceeds through color-singlet annihilation. We illustrate our results for the
case of heavy quark production by light quark annihilation, and briefly discuss
its extension to heavy quark production through gluon fusion.


title: Lattice QCD Spectra at Finite Temperature: a Random Matrix Approach

abstract:
  We suggest that the lattice Dirac spectra in QCD at finite temperature may be
understood using a gaussian unitary ensemble for Wilson fermions, and a chiral
gaussian unitary ensemble for Kogut-Susskind fermions. For Kogut-Susskind
fermions, the lattice results by the Columbia group are in good agreement with
the spectral distribution following from a cubic equation, both for the valence
quark distribution and the anomalous symmetry breaking. We explicitly construct
a number of Dirac spectra for Wilson fermions at finite temperature, and use
the end-point singularities to derive analytically the pertinent critical
lines. For the physical current masses, the matrix model shows a transition
from a delocalized phase at low temperature, to a localized phase at high
temperature. The localization is over the thermal wavelength of the quark
modes. For heavier masses, the spectral distribution reflects on localized
states with competitive effects between the quark Compton wavelength and the
thermal wavelength. Some further suggestions for lattice simulations are made.


title:
Towards a viable grand unified model with $M_G\sim M_{\rm string}$ and
  $M_I\sim 10^{12}$ GeV

abstract:
  We present a model based on the gauge group
SU(2)$_L\times$SU(2)$_R\times$SU(4)$_C$ with gauge couplings that are found to
be unified at a scale $M_G$ near the string unification scale. The model breaks
to the minimal supersymmetric standard model at a scale $M_I\sim 10^{12}$ GeV,
which is instrumental in producing a neutrino in a mass range that can serve as
hot dark matter and this scale can also solve the strong CP problem via
Peccei-Quinn (PQ) mechanism with an invisible harmless invisible axion. We show
how this model can accommodate low and high values of $\tan\beta$ and ``exotic"
representations that often occur in string derived models. We show that this
model has lepton flavor violation which can lead to processes which are one or
two orders of magnitude below the current experimental limits.


title: Helicity Decomposition for Inclusive $J/\psi$ Production

abstract:
  We present a general method for calculating inclusive cross sections for the
production of heavy quarkonium states with definite polarization within the
NRQCD factorization approach. Cross sections for polarized production can
involve additional matrix elements that do not contribute to cross sections for
unpolarized production. They can also include interference terms between parton
processes that produce $Q \bar Q$ pairs with different total angular momentum.
The interference terms cancel upon summing over polarizations. Our method can
be generalized to $N$ dimensions and is therefore compatible with the use of
dimensional regularization to calculate radiative corrections. We illustrate
the method by applying it to the production of $J/\psi$ via the parton
processes $q \bar q \to c \bar c$ and $g g \to c \bar c$.


title:
Possible electric charge nonconservation and dequantization in $SU(2)
  \times U(1)$ models with hard symmetry breaking

abstract:
  We study a novel type of extensions of the Standard Model which include a
hard mass term for the U(1) gauge field and, optionally, the additional scalar
multiplets spontaneously violating the electric charge conservation. Contrary
to the case of abelian massive electrodynamics, in these theories the
massiveness of photon necessarily implies non-conservation (and also
dequantization) of the electric charge (even in the absence of spontaneous
breakdown of the electromagnetic symmetry). On the other hand, unexpectedly,
there exist models with charge non-conservation where it is possible to keep
the photon mass zero (at least, at the tree level).


title: Flavor Structure of Soft SUSY Breaking Parameters

abstract:
  Flavor structure of soft supersymmetry breaking parameters is studied in a
certain type of effective supergravity theory derived from moduli/dilaton
dominated supersymmetry breaking. Some interesting sum rules for soft scalar
masses are presented. They constrain their flavor structure and predict some
interesting patterns appeared in soft scalar masses in the non-universal case.
We also study the alignment phenomena in the flavor space of soft breaking
parameters due to Yukawa couplings and discuss their phenomenological
consequences.


title: Two-body non-leptonic decays on the lattice

abstract:
  We show that, under reasonable hypotheses, it is possible to study two-body
non-leptonic weak decays in numerical simulations of lattice QCD. By assuming
that final-state interactions are dominated by the nearby resonances and that
the couplings of the resonances to the final particles are smooth functions of
the external momenta, it is possible indeed to overcome the difficulties
imposed by the Maiani-Testa no-go theorem and to extract the weak decay
amplitudes, including their phases. Under the same assumptions, results can be
obtained also for time-like form factors and quasi-elastic processes.


title: Dynamical Mass in Strongly Coupled QED

abstract:
  We review dynamical mass generation in three and four dimensional Ableian
gauge theories. The basic approach analyzed here is to solve Schwinger-Dyson
equations in some approximations. In both cases, the coupling has to be larger
than a critical value to have dynamical symmetry breaking. In $QED_4$, chiral
symmetry is spontaneouly broken if $\alpha>\alpha_c (\simeq \pi/3)$ in ladder
approximation. The electron becomes massive, and is realized as Skyrmion in the
low energy effective action. In $QED_3$, electron gets dynmical mass in $1/N$
expansion if $N<N_c(\simeq 32/\pi^2)$. With a Chern-Simons term, parity tends
to break maximally in $QED_3$. The quntum phase structure of $QED_3$ with or
without a Chern-Simons term is peculiar.


title:
Neutrino Oscillation based on the Mixings with a Heavy Right-Handed
  Neutrino

abstract:
  We study a consistent explanation for both deficits of solar neutrino and
atmospheric neutrino due to the neutrino oscillation induced by the mixing of
light neutrinos with a heavy right-handed neutrino. We propose such a
phenomenological neutrino mass matrix that realizes this scenario in the simple
three generation left- and right- handed neutrino framework. Although this
model contains only one nonzero mass eigenvalue $\sim$ 10 eV for these light
neutrino states at the first approximation level, it can be expected to explain
consistently both deficiency due to the appropriate higher order corrections. A
suitable hot dark matter candidate is naturally included in it as its own
feature.


title: Absolute Upper Bound on the 1-loop Corrected mass of $S_1$ in the NMSSM

abstract:
  We examine in detail radiative corrections to the lightest scalar Higgs boson
mass due to the top quark and scalar quark loops in the next-to-minimal
supersymmetric standard model (NMSSM). We take into account the nondegenerate
state for the top scalar quark masses. In our analysis, the mass matrix of the
top scalar quark contains the gauge terms. Therefore our formula for the scalar
Higgs boson mass matrix at the 1-loop level includes the contribution of the
gauge sector as well as the effect of the top scalar quark mass splitting. Thus
we calculate the upper bound on the lightest scalar Higgs boson mass using our
formula. We find that the absolute upper bound on the 1-loop corrected mass of
the lightest scalar Higgs boson is about 156 GeV.


title: LEP Sensitivities to Spontaneous R-Parity Violating Signals

abstract:
  We illustrate the sensitivities of LEP experiments to leptonic signals
associated to models where supersymmetry (SUSY) is realized with spontaneous
breaking of R-parity. We focus on missing transverse momentum plus acoplanar
muon events arising from lightest neutralino single production $\chi \nu$ as
well as pair production $\chi \chi$, followed by $\chi$ decays, where $\chi$
denotes the lightest neutralino. We show that the integrated luminosity
achieved at LEP already starts probing the basic parameters of the theory. We
discuss the significance of these constraints for the simplest spontaneous
R-parity breaking models and their relevance for future searches of SUSY
particles.


title: Multiplicity Moments in QCD and Experiment

abstract:
  QCD predictions for moments of parton multiplicity distributions are
discussed. The next-to-leading terms and conservation law give rise to the
peculiar oscillating shape of some ratio of the moments. The similar shape has
been found by moment analysis of hadron multiplicities. Experimental data,
theoretical Monte Carlo models and phenomenological fits have been used for ee,
hh, hA, AA reactions at high energies.


title: High E$_T$ jets and double scattering

abstract:
  The recently found excess of high E$_T$ jets over current QCD predictions is
attributed to gluon radiation at double scattering process inside a nucleon.
The order of magnitude estimate of the cross section fits experimental findings
rather well. The specific features of the process are discussed. Various
similar hadronic effects related to the short radiation length are described.


title: Moment Analysis of Multiplicity Distributions

abstract:
  Moment analysis of global multiplicity distribution previously done for
$e^{+}e^{-}$ and $hh$ processes is applied to $hA$ and $AA$ collisions. The
oscillations of cumulants as functions of their rank are found in all the
cases. Some phenomenological approaches and quark-gluon string models are
confronted to experimental data. It has been shown that the analysis is a
powerful tool for revealing the tiny features of the distributions, and its
qualitative results in various processes are rather stable for different
multiplicity cut-offs determined by experimental (or Monte-Carlo) statistics.


title: Quantum groups, coherent states, squeezing and lattice quantum mechanics

abstract:
  By resorting to the Fock--Bargmann representation, we incorporate the quantum
Weyl--Heisenberg algebra, $q$-WH, into the theory of entire analytic functions.
The $q$--WH algebra operators are realized in terms of finite difference
operators in the $z$ plane. In order to exhibit the relevance of our study,
several applications to different cases of physical interest are discussed:
squeezed states and the relation between coherent states and theta functions on
one side, lattice quantum mechanics and Bloch functions on the other, are shown
to find a deeper mathematical understanding in terms of $q$-WH. The r\^ole
played by the finite difference operators and the relevance of the lattice
structure in the completeness of the coherent states system suggest that the
quantization of the WH algebra is an essential tool in the physics of
discretized (periodic) systems.


title: Electroweak Baryogenesis in a Supersymmetric Model

abstract:
  In the electroweak phase transition there arises the problem of baryon number
washout by sphaleron transitions, which can be avoided if the phase transition
is strongly enough first order. The phase transition in the Standard Model or
in the Minimal Supersymmetric Standard Model seems to be too weak to suppress
the sphaleron transitions sufficiently. We report here on an investigation of
the Next to Minimal Supersymmetric Standard Model, NMSSM, which contains a
Higgs singlet N in addition to the two Higgs doublets of the minimal SUSY
model. This next to minimal model has the helpful new feature that the Higgs
potential contains a tree level trilinear field term. We consider the most
general form of the Higgs potential without imposing a discrete symmetry; in
particular we allow the presence of a mu-term in the superpotential. We find
that electroweak baryon preservation is compatible with the NMSSM.


title:
Quark-antiquark contribution to the multigluon amplitudes in the
  helicity formalism

abstract:
  Using the helicity formalism, we compute the contribution of a
quark-antiquark pair to the tree-level multigluon amplitudes in the high-energy
limit. The $\bar{q}\, q$-pair production is absent in the leading-log
formalism, but contributes to the next-to-leading corrections to it, and is
therefore relevant for the computation of parton-parton scattering in the
high-energy limit and of the gluon anomalous dimension at small $x_{bj}$, at
next-to-leading accuracy.


title: Mass Hierarchies from Anomalies: a Peek Behind the Planck Curtain

abstract:
  The masses of quarks and leptons suggest a strong hierarchical structure. We
argue that their patterns can be reproduced through the introduction of a new
Abelian symmetry. The data suggest that this symmetry is anomalous. We suggest
that the cancellation of its anomalies occur through the Green-Schwarz
mechanism. An important check of this idea is that it links the Weinberg angle
to a mass ratio of the elementary fermions. The Green-Schwarz mechanism occurs
naturally in many superstring compactifications, and produces a small
parameter, which we use to determine the quark mass hierarchy. We show that
hierarchy and mixings among the chiral fermions is a consequence of the
Green-Schwarz mechanism. We present several models where this idea is realized.


title: Interactions Between Solar Neutrinos and Solar Magnetic Fields

abstract:
  We attempt to correlate all of the available solar-neutrino capture-rate data
with the strong magnetic fields these neutrinos encounter in the solar interior
along their Earth-bound path. We approximate these fields using the
(photospheric, magnetograph-measured) surface magnetic flux from central
latitude bands, time delayed to proxy the solar interior. Our strongest
evidence for anticorrelation is for magnetic fields within the central $\pm
5^{0}$ solar-latitude band that have been delayed by 0.34 years. Assuming a
neutrino-magnetic interaction, this might indicate that interior fields travel
to the solar surface in this period of time. As more solar-neutrino flux
information is gathered, the question of whether such evidence is physical or
statistical in nature should be resolved, providing that new data span enough
solar cycles and that correlation studies focus on these isolated fields.


title:
Chiral Random Matrix Models : Thermodynamics, Phase Transitions and
  Universality

abstract:
  For one flavour, we observe that standard chiral random matrix models are
schematic variants of the Nambu-Jona-Lasinio (NJL) models whether in vacuum or
matter. The ensuing thermodynamics is that of constituent quarks, with
mean-field universality in general. For two and three flavours non-standard
chiral random matrix models with $U_A(1)$ breaking are suggested. For three
flavours the transition is reminiscent of the isotropic-nematic transition in
liquid crystals.


title: Explicit solutions of the n--loop vacuum integral recurrence relations

abstract:
  Explicit formulas for solutions of recurrence relations for 3--loop vacuum
integrals are generalized for the $n$-loop case.


title: Possible Phases in Strong Interaction Vacuum

abstract:
  A study of the possible vacuum phases in a strongly interacting two flavor
light quark system is presented. Four possible phases are found with some of
their properties presented. The possible existence of localized U(1) EM
symmetry breaking phases inside a nucleon and excited hadrons is investigated
by showing the potential of solving three selected current ``puzzles'' in
experimental obervations if such a possibility is taken into account. Base on
these results, the potential of producing these phases in heavy ion collisions
is speculated.


title: SO(10) Models on $Z_6$\ Orbifold with Dual Wilson Line

abstract:
  'Dual' is a promising key word in the particle physics at present. The string
theory is dual in any sense. The observed sector and the hidden sector are dual
on the 10-dim. $E_8\times E_8$ heterotic string. We find $Z_6$ orbifold models
preserving the duality under a torus compactification and realizing $SO(10)$
SUSY GUT in the obserbed sector under a twist division.


title: Proton Stability and Small Neutrino Mass in String Inspired $E_6$ Models

abstract:
  We propose a new possibility to realize simultaneously the sufficient proton
stability and the interesting structure of neutrino mass matrix in superstring
inspired $E_6$ models. In this model the leptons and Higgs fields are assigned
to a fundamental representation {\bf 27} in the different way among
generations. Two pairs of Higgs doublets naturally remain light from three
generation ones by imposing certain discrete symmetries, although all extra
color triplets become sufficiently heavy. Under these symmetries suitable
$\mu$-terms to bring appropriate vacuum expectation values are prepared and the
dangerous FCNC is avoidable. Some related phenomena to this model, especially,
the structure of neutrino mass matrix are also discussed.


title: The Strong g_B(**)BPi Coupling Constant in full QCD

abstract:
  To leading order in alpha_s, the leading and non-leading 1/m_b corrections to
the excited g_B^(**) meson coupling g_B^(**)BPi is calculated in the framework
of QCD spectral moment sum rules in the full theory. Our prediction is in good
agreement=20 with the light-cone QCD sum rule result.


title: Heavy Quark Fragmentation into Baryons in a Quark-Diquark Model

abstract:
  In the framework of the nonrelativistic QCD and a quark-diquark model of
baryons we have obtained the fragmentation functions for heavy quark to split
into spin-1/2 and spin-3/2 double heavy baryons. It was predicted the
production rates as well as the shape of the energy spectra for the $cc-$ and
$bc-$baryons in the region of $Z^o$ peak at LEP collider.


title: An Elusive Z' Coupled to Beauty

abstract:
  By extending the standard gauge group to SU(3)_c \times SU(2)_L \times U(1)_Y
\times U(1)_X with X charges carried only by the third family we accommodate
the LEP measurement of R_b and predict a potentially measurable discrepancy in
A_{FB}^{b} in e^+e^- scattering and that D^0\bar{D}^0 mixing may be near its
experimental limit. The Z', which explicitly violates the GIM mechanism, can
nevertheless be naturally consistent with FCNC constraints. Direct detection of
the Z' is possible but challenging.


title: Diffractive Contribution to $g_1$ Structure Function at Small $x$

abstract:
  We study the small $x$ diffractive contribution to the spin--dependent proton
structure function $g_1(x)$. We find that the $x\to 0$ behaviour of $ g_1(x)$
has a singular form like $1/(x^\alpha \ln^2(x))$ with $\alpha \sim 0.2-0.3$.


title: Would unitarity slow down the rise of $F_2(x,Q^2)$ at $x\to 0$?

abstract:
  On the grounds of the $U$--matrix form of $s$--channel unitarization, we
consider constraints unitarity provides for the total cross--section of the
virtual photon--induced reactions and discuss the preasymptotic nature of
hadron and photon scatterings at $\sqrt{s}\leq 0.5$ TeV.