title: Heavy Quark Hadronic Lagrangian for S-wave Quarkonium

abstract:
  We use Heavy Quark Effective Theory (HQET) techniques to parametrize certain
non-perturbative effects related to quantum fluctuations that put both heavy
quark and antiquark in quarkonium almost on shell.
  The large off-shell momentum contributions are calculated using Coulomb type
states. The almost on-shell momentum contributions are evaluated using an
effective 'chiral' lagrangian which incorporates the relevant symmetries of the
HQET for quarks and antiquarks. The cut-off dependence of both contributions
matches perfectly. The decay constants and the matrix elements of bilinear
currents at zero recoil are calculated. The new non-perturbative contributions
from the on-shell region are parametrized by a single constant. They turn out
to be $O(\alpha^2/\Lambda_{QCD} a_{n})$, $a_{n}$ being the Bohr radius and
$\alpha$ the strong coupling constant, times the non-perturbative contribution
coming from the multipole expansion (gluon condensate). We discuss the physical
applications to $\Upsilon$, $J/\Psi$ and $B_{c}$ systems.


title:
Comment on "The Phenomenology of a Nonstandard Higgs Boson in W_L W_L
  Scattering"

abstract:
  We show that in Composite Higgs models, the coupling of the Higgs resonance
to a pair of $W$ bosons is weaker than the corresponding Standard Model
coupling, provided the Higgs arises from electroweak doublets only. This is
partly due to the effects of the nonlinear realization of the chiral symmetries
at the compositeness scale.


title: Second-Order Scaling in the Two-Flavor QCD Chiral Transition

abstract:
  Scaling behavior is analyzed for the two-flavor QCD lattice gauge theory
chiral transition. Leading scaling behavior and correction to leading scaling
from lattice spacing effects are examined for the quark condensate. Scaling
predictions under the assumption of quark mass dominance are tested for the
longitudinal correlation length. Second order scaling behavior is consistent
with present data.


title: High Density QCD and Entropy Production at Heavy Ion Colliders

abstract:
  The role of entropy production in the context of probing QCD properties at
high densities and finite temperatures in ultra-relativistic collisions of
heavy nuclei is inspected. It is argued that the entropy generated in these
reactions provides a powerful tool to investigate the space-time evolution and
the question whether and how a deconfined plasma of quarks and gluons is
formed. I will address the questions how entropy is produced, and how it is
measurable. The uncertainties in predicting the different contributions to the
total entropy and particle multiplicities during the course of heavy ion
collisions are also discussed.


title: Model independent determination of |Vub| in heavy meson effective thoery

abstract:
  We propose a strategy of the model-independent determination of the
Kobayashi-Maskawa matrix element $|V_{ub}|$ within the framework of the heavy
meson effective theory. The effective theory is model-independent, since no
assumption on the dynamics is introduced except for the symmetry of QCD.
Although the effective theory can only be applied to the decay process with
soft pions, high detection efficiency on the soft pions in the future
B-factories makes this theory effective. The two exclusive processes, $B
\rightarrow \pi l \nu$ and $B \rightarrow \pi \pi l \nu$, are used to determine
the value of $|V_{ub}|$, under the condition that the values of the decay
constants of $B$ and $B^*$ mesons are given.


title:
Testing factorization in colour-suppressed beauty decays with the B ->
  \eta_c + K(K^*) modes

abstract:
  The large discrepancy recently observed between $B \ra J/\Psi + K (K^*)$ data
and commonly used hadronic form factor models might be due to a breakdown of
the factorization assumption. By showing that the $B \ra \eta_c + K (K^*)$
rates can be calculated without relying on any form factor model, we propose a
test of the factorization hypothesis. This test is free of possible
uncertainties caused by final state interactions and $W$-exchange graph
contributions. If factorization holds, the measurable ratio $\Gamma(B \ra
\eta_c + K^*)/\Gamma(B \ra \eta_c + K )$ is predicted to be in the range from
0.18 to 0.95 when the CLEO II data on $B \ra J/\Psi + K (K^*)$ are used.


title: QCD corrections to inclusive $\Delta S=1,2$ transitions

abstract:
  The talk summarises a calculation of the two-point functions for $\Delta S=1$
current-current and QCD-penguin operators, as well as for the $\Delta S=2$
operator, at the next-to-leading order. The size of the gluonic corrections to
current-current operators is large, providing a qualitative understanding of
the observed enhancement in $\Delta I=1/2$ transitions. In the $\Delta S=2$
sector the QCD corrections are quite moderate ($\approx -20\%$). This work has
been done in collaboration with Antonio Pich.


title: New phenomena in the standard no-scale supergravity model

abstract:
  We revisit the no-scale mechanism in the context of the simplest no-scale
supergravity extension of the Standard Model. This model has the usual
five-dimensional parameter space plus an additional parameter $\xi_{3/2}\equiv
m_{3/2}/m_{1/2}$. We show how predictions of the model may be extracted over
the whole parameter space. A necessary condition for the potential to be stable
is ${\rm Str}{\cal M}^4>0$, which is satisfied if $\bf m_{3/2}\lsim2 m_{\tilde
q}$. Order of magnitude calculations reveal a no-lose theorem guaranteeing
interesting and potentially observable new phenomena in the neutral scalar
sector of the theory which would constitute a ``smoking gun'' of the no-scale
mechanism. This new phenomenology is model-independent and divides into three
scenarios, depending on the ratio of the weak scale to the vev at the minimum
of the no-scale direction. We also calculate the residual vacuum energy at the
unification scale ($C_0\, m^4_{3/2}$), and find that in typical models one must
require $C_0>10$. Such constraints should be important in the search for the
correct string no-scale supergravity model. We also show how specific classes
of string models fit within this framework.


title:
CP Violation in the Heavy Neutrinos Production Process
  $e^+e^-\rightarrow N_1N_2$

abstract:
  The problem of CP conservation and CP violation for two heavy neutrinos
production in $e^+e^-$ interaction is considered. Very convenient way of
parametrization of the neutrino mass matrix, from which necessary and
sufficient condition for CP conservation easily follows, is presented. Contrary
to the Kobayashi-Maskawa mechanism, the effects of CP violation in the lepton
sector with Majorana neutrinos can be very large. Change of the total cross
section caused by CP violation can be much larger then the cross section
itself.


title:
Higgs Boson Contributions to Neutrino Production in e-e+ Collisions in a
  Left-Right Symmetric Model

abstract:
  In gauge models with bigger number of Higgs particles their couplings to
fermions are more complicated then in the standard model (SM). The influence of
the Higgs bosons exchange on the neutrino production cross section in $e^-e^+$
collision ($e^-e^+ \rightarrow \nu N$) is investigated. The study has been done
in the framework of the left-right symmetric model with the rich Higgs sector
containing bidoublet and two triplets. The couplings of the Higgs particles
even to light leptons can be as large as the gauge bosons couplings. The total
effect of the Higgs bosons is small as a result of the big Higgs mass in the
propagators.


title:
Some Prospects for the Determination of the Unitarity Triangle Before
  the LHC Era

abstract:
  Anticipating improved determinations of $m_t$, $|V_{cb}|$, $|V_{ub}/V_{cb}|$,
$B_K$ and $F_B \sqrt{B_B}$ in the next five years we make an excursion into the
future in order to find a possible picture of the unitarity triangle, of quark
mixing and of CP violation around the year~2000. We then analyse what impact on
this picture will result from the measurements of the four possibly cleanest
quantities: $BR(K^+ \to \pi^+ \nu \bar\nu)$, $x_d/x_s$, $\sin(2\alpha)$ and
$\sin(2\beta)$. In the course of our investigations we extend the analysis of
the unitarity triangle beyond the leading order in the Wolfenstein parameter
$\lambda$. \\ We will also shortly present the status of direct CP violation in
$K \rightarrow \pi\pi$ and $K_{\rm L} \rightarrow \pi^0 e^+ e^-$.


title: Singlet Charge $2/3$ Quark hiding the Top: Tevatron and LEP Implications

abstract:
  If $c$ and $t$ quarks are strongly mixed with a weak singlet charge $2/3$
quark, $BR(t\to \ell\nu + X)$ could be suppressed via the $t\to cH^0$ mode,
thereby the top quark could still hide below $M_W$, whereas the heavy quark
signal observed at the Tevatron is due to the dominantly singlet quark $Q$.
This may occur without affecting the small $m_c$ value. Demanding $m_Q \simeq
175$ GeV and $m_t \ltap M_W$, we find that $BR(t\to \ell\nu + X)$ cannot be too
suppressed. The heavy quark $Q$ decays via $W,\ H$, and $Z$ bosons. The latter
can lead to $b$-tagged $Z + 4$ jet events, while the strong $c$--$Q$ mixing is
reflected in sizable $Q\to sW$ fraction. $Z\to t\bar c$ decay occurs at tree
level and may be at the $10^{-3}$ order, leading to the signature of $Z\to
\ell\nu b\bar c$, all isolated and with large $p_T$, at $10^{-5}$ order.


title: Looking Beyond the Standard Model

abstract:
  Within the framework of the Standard Model, the scale of electroweak symmetry
breaking is unstable to radiative corrections. We discuss two broad classes of
models of new physics (one with a strongly interacting and the other with a
perturbatively coupled electroweak symmetry breaking sector) in which this
stability is restored. After reviewing experimental constraints on these, we
discuss the implications of these types of models for experiments, both at
currently operating colliders as well as the next generation of colliders under
consideration for construction. Other extensions of the Standard Model are
briefly alluded to.


title: Enhancement of CP Violation in B^+- to K_i^+- D^0 By Resonant Effects

abstract:
  Resonance width effects in charged $B$ decays to neutral $D$ mesons and
excited kaon states $K_i$ around 1400 MeV are shown to lead to large calculable
final state phases. $CP$ asymmetries are defined for any charged $B$ decay to
three pseudoscalar mesons involving intermediate overlapping resonance states.
Asymmetries up to about 10$\%$ are found in $B^+\to K^+_i D^0\to (K\pi)^+ D^0$.
Decay distributions can be used to determine the weak phase $\gamma$ of the
Cabibbo-Kobayashi-Maskawa (CKM) matrix. No separation of the contributions from
individual resonances is required.


title: Higher-order QCD corrections to deep-inelastic sum rules

abstract:
  The brief review of the current status of the studies of the effects of the
higher-order perturbative QCD corrections to the deep-inelastic sum rules is
presented.


title: 2 and 3-point functions in the ENJL-model

abstract:
  We discuss the extended Nambu-Jona-Lasinio model as a low energy expansion,
all two-point functions and an example of a three-point function to all orders
in momenta and quark masses. The model is treated at leading level in $1/N_c$
but otherwise exact. Some comments about the QCD flavour anomaly and Vector
Meson Dominance in this class of models is made. Uses epsf.sty and rotate.sty.
One postscript figure included at the end.


title: A possible resolution of the CDF psi^prime anomaly

abstract:
  We consider the contribution of radially excited 2^3P_{1,2} states to
psi^prime production at the Tevatron energy. Production of these states via the
conventional gluon fusion mechanism and via gluon and charm quark fragmentation
processes is considered. We find that it is possible to account for the data on
psi^prime production from the CDF experiment, by taking into account the decays
of these 2^3P_{1,2} states into psi^prime.


title: Physics Beyond the Standard Model: Prospects and Perspectives

abstract:
  In this talk I discuss the effects of physics beyond the standard model on
the process $Z \to b\bar{b}$. I argue that, because the top-quark is heavy,
this process is susceptible to large corrections from new physics.


title: CP Violation in a Multi-Higgs Doublet Model

abstract:
  We study CP violation in a multi-Higgs doublet model based on a $S_3 \times
Z_3$ horizontal symmetry. We consider two mechanisms for CP violation in this
model: a) CP violation due to complex Yukawa couplings; and b) CP violation due
to scalar-pseudoscalar mixings. We find that the predictions for
$\epsilon'/\epsilon$, CP violation in B decays and the electric dipole moments
of neutron and electron are different between these two mechanisms. These
predictions are also dramatically different from the minimal Standard Model
predictions.


title: Proton Decay In Supersymmetric Finite Grand Unificatione

abstract:
  We study proton decay in finite supersymmetric SU(5) grand unified theories.
We find that the finite supersymmetric SU(5) models are ruled out from this
consideration.


title: CP Violation In Hyperon Decays

abstract: The present status for CP violation in hyperon decays is reviewed.


title: A Light $Z'$ Boson

abstract:
  A model of a light $Z'$ boson based on gauged $L_\mu - L_\tau$ $U(1)$
symmetry is constructed. The $Z'$ boson mass is constrained to be in the range
of 0.8 to 1 GeV from Z and $Z'$ mass relation, g-2 of muon, and tau decays. The
two body decay $\tau \rightarrow \mu Z'$ is possible. This will provide a
striking signature to test the model. Talk presented at the Eighth Meeting of
the American Physical Society, Division of Particles and Fields (DPF'94),
Albuqurque, New Mexico, August 2-6, 1994.


title:
Additional Soft Jets in ${\rm t\bar{t}}$ Production at the Tevatron
  $\pp$ Collider

abstract:
  A large fraction of top quark events in $\pp$ collisions at $1.8\ \TeV$ will
contain additional soft hadronic jets from gluon bremsstrahlung off the quarks
and gluons in the hard processes $\qq, gg \to \tt \to \bb \ww$. These extra
jets can cause complications when attempting to reconstruct $m_t$ from the
invariant mass of combinations of final-state quarks and leptons. We show how
such soft radiation cannot be unambiguously associated with either
initial-state radiation or or with final-state radiation off the $b$ quarks.
The top quarks can radiate too, and in fact the pattern of radiation has a very
rich structure, which depends on the orientation of the final-state particles
with respect to each other and with respect to the beam. We calculate the full
radiation pattern of soft jets in the soft gluon approximation and compare with
several approximate forms which are characteristic of parton shower Monte
Carlos. The implications for top mass measurements are discussed.


title: Supersymmetry at LEPII, the Tevatron, and Future Accelerators

abstract:
  I present a brief review of prospects for discovering supersymmetry, focusing
primarily on the Tevatron and LEPII, but commenting on the LHC and a next
linear $\epem$ collider. Special emphasis is given to expectations in the
context of models with GUT boundary conditions motivated by Supergravity and
Superstrings. An overview of related conference contributions is given.


title: $b \to s(d) \gamma$ with a Vector-like Quark as Fourth-generation

abstract:
  We study the implications of a vector-like quark, especially a down-type
vector-like quark in $b \rightarrow s(d) \gamma$ including the neutral Higgs in
the calculation. After analyzing some possible constraints for the mixing, the
contribution may be significant for the $b \rightarrow d \gamma$, but not for
the $b \rightarrow s \gamma$. We also find that the FCNC among ordinary quarks
vanishes for a special form of down-type quark mass matrix.


title: Meson Supermultiplet Decay Constants

abstract:
  We use a covariant supermultiplet theory to determine the primary coupling
constant associated with several types of two-body meson decay. Despite the
diverse range of decays considered the primary coupling constant is
surprisingly uniform. We envisage the extension of the techniques to heavy
quark cases, including as preliminary examples the calculation of the $D^{*+}$
and $D^{*0}$ total decay widths with results $57.7 \pm 1.5$ KeV and $42.5 \pm
2.6$ KeV respectively, as well as some predictions about $D^*$ and $B^*$
radiative decays. (3 uuencoded Postscript Files are appended at the end of the
TexFile.)


title:
Towards Precise Determinations of the CKM Matrix without Hadronic
  Uncertainties

abstract:
  We illustrate how the measurements of the CP asymmetries in
$B^0_{d,s}$-decays together with a measurement of $Br(K_L\to
\pi^\circ\nu\bar\nu)$ or $Br(K^+\to \pi^+\nu\bar\nu)$ and the known value of
$\mid V_{us}\mid $ can determine all elements of the Cabibbo-Kobayashi-Maskawa
matrix essentially without any hadronic uncertainties. An analysis using the
ratio $x_d/x_s$ of $B_d-\bar B_d$ to $B_s-\bar B_s$ mixings is also presented.


title: Top Quarks and $CP$ Violation in Polarized $e^+e^-$ Collisions

abstract:
  Electroweak dipole moments of the top quark are conjectured and their effect
in polarized $e^+e^-$ collisions is examined for the expectation values of two
different $CP$-odd observables. One of these observables probes the real part
of the dipole moments whereas the other probes their imaginary part. It turns
out that varying the polarization of the electron beam substantially enhances
the resolving power of the experiment. PostScript version: preprints/mpi9454.ps
from gluon.hep.physik.uni-muenchen.de


title:
Limitations in Measuring the Angle $\beta$ by Using $SU(3)$ Relations
  for $B$-Meson Decay-Amplitudes

abstract:
  Flavour $SU(3)$ symmetry of strong interactions and certain dynamical
assumptions have been used in a series of recent publications to extract weak
CKM phases from $B$-decays into $\{\pi\pi,\pi K, K\bar K\}$ final states. We
point out that irrespectively of $SU(3)$-breaking effects the presence of
QCD-penguin contributions with internal $u$- and $c$-quarks precludes a clean
determination of the angle $\beta$ in the unitarity triangle by using the
branching ratios only. This difficulty can be overcome by measuring in addition
the ratio $x_d/x_s$ of $B^0_d-\bar B^0_d$ to $B^0_s-\bar B^0_s$ mixings. The
measurement of the angle $\gamma$ is unaffected by these new contributions.
Some specific uncertainties related to $SU(3)$-breaking effects and electroweak
penguin contributions are briefly discussed.


title: Operator product expansion and duality at finite temperature

abstract:
  The operator product expansion of current correlators at short distances, and
the notion of QCD-hadron duality are the cornerstone of QCD sum rules. The
extension of this programme to $T \neq 0$ is discussed, together with
applications to hot hadronic propagators. Indications are that the hadronic
spectrum suffers a substantial rearrangement with increasing temperature, and
hint on the existence of a quark deconfining phase transition. Phenomenological
order parameters to characterize this phase transition are discussed.


title: Braaten-Pisarski Method at Finite Chemical Potential

abstract:
  The effective perturbation theory developed by Braaten and Pisarski for gauge
theories at finite temperature is extended to finite chemical potential. As a
first application the collisional energy loss of a heavy quark propagating
through a quark-gluon plasma with non-vanishing quark chemical potential is
considered. Assuming $\mu /T\simeq 1$, motivated by numerical simulations of
heavy ion collisions at RHIC energies, we find that the effect of the quark
chemical potential is rather small, unless the energy density instead of the
temperature is fixed.


title: Theory of Semi-- and Nonleptonic Decays of Heavy Mesons

abstract:
  I review some of the recent developments in the theoretical description of
weak inclusive decays of heavy mesons. The topics cover the value of $|V_{cb}|$
as extracted from semileptonic inclusive decays and a short discussion of the
theoretical errors. I also present the results of a recent calculation of
next--to--leading order corrections to nonleptonic inclusive B decays which
allows an improved prediction of the semileptonic branching ratio of B mesons.


title: About Entropy and Thermalization - a Miniworkshop Perspective

abstract:
  We present a summary and perspective view of the Miniworkshop on ``{\it
Entropy and Thermalization}'' in strong interactions (convener J. Rafelski),
which was part of the NATO Advanced Research Workshop on ``{\it Hot Hadronic
Matter}'' that took place in Divonne, 27 June to 1 July 1994. To appear in the
Proceedings (Plenum Press).


title: Anomalous Evolution of Nonsinglet Structure Functions

abstract:
  We review a formalism that includes the effects of nonperturbative U(1)
symmetry breaking on the QCD evolution of nonsinglet structure functions. We
show that a strong scale dependence is generated in an intermediate energy
range $0.5 \lsim Q^2 \lsim 5$~GeV$^2$ for all values of $x$. We show that this
explains naturally the observed violation of the Gottfried sum, and allows a
determination of the shape of the nonsinglet structure function, in excellent
agreement with experiment. We argue that these effects may affect the
determination of $\alpha_s$ from deep--inelastic scattering.


title: Hydrodynamic Transport Coefficients in Relativistic Scalar Field Theory

abstract:
  Hydrodynamic transport coefficients may be evaluated from first principles in
a weakly coupled scalar field theory at arbitrary temperature. In a theory with
cubic and quartic interactions, the infinite class of diagrams which contribute
to the leading weak coupling behavior are identified and summed. The resulting
expression may be reduced to a single linear integral equation, which is shown
to be identical to the corresponding result obtained from a linearized
Boltzmann equation describing effective thermal excitations with temperature
dependent masses and scattering amplitudes. The effective Boltzmann equation is
valid even at very high temperature where the thermal lifetime and mean free
path are short compared to the Compton wavelength of the fundamental particles.
Numerical results for the shear and the bulk viscosities are presented.


title: Axion search with optical technique

abstract:
  A brief review of particle physics motivations for axion existence is
followed by a discussion of optical observables that can be used for axion
detection. It is emphasised that the resonant photon - axion transition can
occur in the presence of low density gas bringing the experimentally accessible
quantities within the reach of the present day technology.


title: Z Plus Four Jets Production in Hadronic Collisions

abstract:
  We present first results of $Z+4$ jet cross sections at the Tevatron $p\bar
p$ collider with heavy quark flavor identification. The $Z + 4$ jet channel is
of particular interest as a normalizer for the $W +4$ jet background to top
quark signals, as a background to a possible $t\to cZ$ flavor-changing
neutral-current (FCNC) decay signal, and as a background to missing-$p_T$
signals from gluino pairs. We also calculate the different heavy flavor
contributions to $W+4$ jet production. The MADGRAPH program is used to generate
all leading order subprocess helicity amplitudes. We present Monte Carlo
studies with separation and acceptance criteria suitable for the Tevatron
experimental analyses.


title: Charm Production at RHIC and LHC to $O(\alpha_{s}^3)$

abstract:
  We present results on rapidity and transverse momentum distributions of
inclusive charm quark production in hadronic and heavy-ion collisions at RHIC
and LHC energies, including the next-to-leading order, $O(\alpha_s^3)$,
radiative corrections and the nuclear shadowing effect. We determine hadronic
and nuclear K-factor for the differential and total inclusive cross sections
for the charm production. We discuss theoretical uncertainties inherent in our
calculation. In particular, we find that different extrapolations of gluon
density to low-$x$ region introduce large theoretical uncertainty in the
calculation of charm production at LHC energies. Finally, we comment on the
possibility of detecting the quark-gluon plasma signal as an enhanced charm
production in heavy-ion collisions at RHIC.


title: Positivity Constraints for Spin-Dependent Parton Distributions

abstract:
  We derive new positivity constraints on the spin-dependent structure
functions of the nucleon. These model independent results reduce conside\-rably
their domain of allowed values, in particular for the chiral-odd parton
distribution $h_1 (x)$.


title: $B_K$ and Explicit Chiral Symmetry Breaking

abstract:
  The $B_K$ parameter is discussed in the general context of calculating beyond
the factorization approximation for hadronic matrix elements. A variant of the
$1/N_c$ method of Bardeen et al. is used. We present calculations within a low
energy approach and a calculation within the Nambu--Jona-Lasinio model.
Matching with the QCD behaviour and dependence on non-zero current quark masses
is studied.


title: Lambda-bar from QCD sum rules for heavy quarkonium

abstract:
  Using a specific scheme of the QCD sum rules for heavy quarkonium in the
leading approximation over the inverse heavy quark mass, one gets the estimate
of the difference between the masses of the heavy meson and heavy quark $\bar
\Lambda = 0.59\pm 0.02$ GeV.


title: MRS(1994): parton distributions of the proton

abstract:
  To obtain improved parton densities of the proton, we present a new global
analysis of deep-inelastic and related hard scattering data including, in
particular, the recent measurements of F2 at HERA, of the asymmetry of the
rapidity distributions of W+- production at the FNAL pbar p collider and of the
asymmetry in Drell-Yan production in pp and pn collisions. We discuss the
evolution of the new partons to low values of Q2.


title: Comments on QCD Corrections to $b \to s \gamma$ Decay

abstract:
  We find some errors in previous calculation of leading log QCD corrections to
$b \to s\gamma $ decay, which include corrections from $m_{top}$ to $M_W$ in
addition to corrections from $M_{W}$ to $m_b$. The inclusive decay rate is
found to be enhanced more than previous calculations. At $m_t=170$GeV, the
running from $m_{top}$ to $M_W$ results in 13\% enhancement, and for
$m_t=250$GeV, 16\% is found.


title:
\Omb \rightarrow \Omc , \Omc ^* $ transitions: Model-independent bounds
  on invariant form factors

abstract:
  In this note we report some model-independent bounds involving transition
form factors for $ \Omb \rightarrow \Omc $ and $ \Omb \rightarrow \Omc ^* $ and
the nonperturbative matrix elements of the $ \Omb $ system. They are derived by
using operator product expansion (OPE) in Heavy Quark Effective Theory .


title: Unitarity Constraints for New Physics Induced by dim-6 Operators

abstract:
  We compute the helicity amplitudes for boson-boson scattering at high energy
due to the operators $\O_{B\Phi}$, $\O_{W\Phi}$ and $\O_{UB}$, and we derive
the corresponding unitarity bounds. Thus, we provide relations between the
couplings of these operators and the corresponding New Physics thresholds,
where either unitarity is saturated or new degrees of freedom are excited. We
compare the results with those previously obtained for the operators $\O_W$ and
$\O_{UW}$ and we discuss their implications for direct and indirect tests at
present and future colliders. The present treatment completes the study of the
unitarity constraints for all blind bosonic operators.


title: Non-factorization and the Decays B into J/psi + K(*)

abstract:
  Many known models, which generally use a factorization hypothesis, give a
poor account of the decays B into J/psi + K(*). Usually there is a free overall
factor, which is fit to the data, so that tests of the models rely upon ratios.
The models tend to give too much K* compared to K and too much transverse
polarization compared to longitudinal. Our microscopic calculations, which use
perturbative QCD, do well for both ratios. A microscopic calculation allows us
to see how well factorization, heavy quark symmetry, and other features of
various models are working. In the present case, agreement with the
experimental ratios is dependent upon a breakdown of factorization for one of
the amplitudes.


title: Electromagnetic Form Factors at Large Momentum Transfer

abstract:
  Recent improvements of the hard scattering picture for the large $p_{\perp}$
behaviour of electromagnetic form factors, namely the inclusion of both Sudakov
corrections and intrinsic transverse momentum dependence of the hadronic wave
function, are reviewed. On account of these improvements the perturbative
contributions to the pion's and the nucleon's form factor can be calculated in
a theoretically self-consistent way for momentum transfers as low as about $2$
and $3\,{\rm GeV}$, respectively. This is achieved at the expense of a
substantial suppression of the perturbative contribution in the few GeV region.
Eventual higher twist contributions are discussed in some detail.


title:
Extracting the Intermediate-Mass Higgs Resonance at Photon-Photon
  Colliders

abstract:
  We address the problem of how to extract the signal of a Higgs within the
intermediate mass range at a photon-photon collider that has a wide energy
spectrum. All backgrounds from two-jets production are included: direct,
so-called resolved and twice-resolved as well as single $Z$ and $W$ production.
Uncertainties in the evaluation of the QCD-initiated processes such as the
choice of structure function and the issue of radiative corrections are
discussed. We consider various combinations of the polarizations and invariant
mass resolutions as well as jet-tagging strategies with different efficiencies.
The analysis is based on an automatized technique that, given a specific
detector and machine configuration, returns the optimal set of cuts
corresponding to the best significance one may hope to achieve for each
particular Higgs mass. We find that at a photon machine obtained from a 500GeV
\epm\ linear collider with $\int\!{\cal L}=10$~fb$^{-1}$ it will be possible to
extract a Higgs signal in the range 110--140~GeV, while with the same
luminosity, a 350~GeV option not only extends the discovery limit down to
90~GeV but gives much better significance levels.


title: Testing Supersymmetry at the Next Linear Collider

abstract:
  If new particles are discovered, it will be important to determine if they
are the supersymmetric partners of standard model bosons and fermions.
Supersymmetry predicts relations among the couplings and masses of these
particles. We discuss the prospects for testing these relations at a future
$e^+e^-$ linear collider with measurements that exploit the availability of
polarized beams.


title: Fusing Gauge Theory Tree Amplitudes Into Loop Amplitudes

abstract:
  We identify a large class of one-loop amplitudes for massless particles that
can be constructed via unitarity from tree amplitudes, without any ambiguities.
One-loop amplitudes for massless supersymmetric gauge theories fall into this
class; in addition, many non-supersymmetric amplitudes can be rearranged to
take advantage of the result. As applications, we construct the one-loop
amplitudes for $n$-gluon scattering in $N=1$ supersymmetric theories with the
helicity configuration of the Parke-Taylor tree amplitudes, and for six-gluon
scattering in $N=4$ super-Yang-Mills theory for all helicity configurations.


title: Heavy Polonyi Field as a Solution of the Polonyi Problem

abstract:
  We study properties of the Polonyi field in the renormalizable hidden sector
in supergravity models. It is shown that radiative corrections induce a sizable
coupling of the Polonyi field to gravitinos as well as raise its mass to an
intermediate scale. We find it serves a solution of the Polonyi problem and
show that the gravitino abundance produced by the Polonyi decay is not large.
It is also pointed out that soft supersymmetry breaking terms induced by this
hidden sector are very restricted.


title:
Late-time Phase transition and the Galactic halo as a Bose Liquid: (II)
  the Effect of Visible Matter

abstract:
  In the previous work, we investigated the rotation curves of galaxies
assuming that the dark matter consists of ultra light boson appearing in
$'$late time phase transition' theory. Generalizing this work, we consider the
effect of visible matter and classify the types of rotation curves as we vary
the fraction of the mass and extention of visible matter. We show that visible
matter, in galaxies with flat rotation curves, has mass fraction $ 2\% \sim
10\% $ and it is confined within the distance fraction $ 10\% \sim 20\%$.


title: Hyperon in Chiral Effective Quark Models

abstract:
  Baryonic correlation functions are calculated within an effective chiral
quark model motivated by the instanton liquid model of QCD. Using a flavour
SU(3) symmetry for the local four-quark interaction and taking rotational zero
modes for the quantization into account low-energy hadronic observables are in
surprising agreement with experimental data. (Talk presented at the Conference
on Hypernuclear and Strange Particle Physics (HYP94), Vancouver, B.C., Canada,
4.-8- Juli 1994)


title:
Higher Order Corrections to the Equation of State of QED at High
  Temperature

abstract:
  We elaborate on the computation of the pressure of thermal quantum
electrodynamics, with massless electrons, to the fifth ($e^5$) order. The
calculation is performed within the Feynman gauge and the imaginary-time
formalism is employed. For the $e^4$ calculation, the method of Sudakov
decomposition is used to evaluate some ultraviolet finite integrals which have
a collinear singularity. For the $e^5$ contribution, we give an alternative
derivation and extend the discussion to massive electrons and nonzero chemical
potential. Comments are made on expected similarities and differences for
prospective three-loop calculations in QCD.


title: Heavy Sneutrinos as Dark Matter

abstract:
  We calculate the relic density of very heavy, stable scalar neutrinos in the
minimal supersymmetric standard model. We include all two-body final states, as
well as the effects of co-annihilation with scalar electrons. We find that the
sneutrino relic density is in the cosmologically interesting region
$0.1\ltwid\Omega_{\sn}h^2\ltwid 1.0$ for $550\gev\ltwid\msn\ltwid 2300\gev$.
For nominal values of the parameters of our galactic halo, recent results from
the Heidelberg--Moscow direct detection experiment set an upper limit on
$\Omega_{\sn}$ which is lower by a factor ranging from two to ten, depending on
$\msn$.


title:
Instanton-induced production of jets with large transverse momentum in
  QCD

abstract:
  We consider the instanton-induced cross section for production of a gluon jet
with large transverse momentum in QCD and point out that Mueller's corrections
corresponding to the rescattering of hard quanta are likely to remove
contributions of large instantons, making this cross section well defined. Some
speculations about possible phenomenological signatures are presented.


title: Beta decay of hyperons in a relativistic quark model

abstract:
  A relativistic constituent quark model is used to calculate the semileptonic
beta decay of nucleons and hyperons. The parameters of the model, namely, the
constituent quark mass and the confinement scale, are fixed by a previous
calculation of the magnetic moments of the baryon octet within the same model.
We discuss the momentum dependence of the form factors, possible configuration
mixing and SU(3) symmetry breaking. We conclude that the relativistic
constituent quark model is a good framework to analyze electroweak properties
of the baryons.


title:
Algebraic Reduction of Feynman Diagrams to Scalar Integrals: a
  Mathematica implementation of LERG-I

abstract:
  A Mathematica implementation of the program LERG-I is presented that performs
the reduction of tensor integrals, encountered in one-loop Feynman diagram
calculations, to scalar integrals. The program was originally coded in REDUCE
and in that incarnation was applied to a number of problems of physical
interest.


title: Baryogenesis from Long Cosmic Strings

abstract:
  Based on the mechanism of cusp production on long cosmic strings, the baryon
asymmetry caused by cusp annihilation has been calculated. The result is
compatible with observation and stronger than the results from loops.


title: A New Technique for Detecting Supersymmetric Dark Matter

abstract:
  We estimate the event rate for excitation of atomic transition by
photino-like dark matter. For excitations of several eV, this event rate can
exceed naive cross-section by many orders of magnitude. Although the event rate
for these atomic excitation is smaller than that of nuclear recoil off of
non-zero spin nuclei, the photons emitted by the deexcitation are easier to
detect than low-energy nuclear recoils. For many elements, there are several
low-lying states with comparable excitation rates, thus, spectral ratios could
be used to distinguish signal from background.


title: Top Momentum and Extra Soft Jets

abstract:
  Top pairs produced at the Tevatron may be accompanied by extra jets due to
radiation of soft gluons. Whether these jets should be included in top momentum
reconstruction depends on the source of the gluons, which can be radiated off
the initial partons, the final state $b$ quarks, or the intermediate top
quarks. We compute soft gluon distributions and discuss their implications for
top mass measurements.


title: Light Flavor Dependence of the Isgur-Wise Function

abstract:
  We present an investigation on the ligh flavor dependence of the Isgur-Wise
function for $B_a\rightarrow D_a$ and $B_a\rightarrow D^{*}_a$ in the framework
of QCD sum rules. It is found that the Isgur-Wise function for $B_s$ decay
falls faster than that for $B_{u,d}$ decay , which is just contrary to the
recent prediction of the heavy meson chiral perturbation theory. SU(3) symmetry
breaking effects in the mass and the decay constant are also estimated.


title: The role of zero modes for the infrared behavior of QCD

abstract:
  We analyse the mechanism in which zero modes lead to an elimination of
fermionic color non--singlet states in 1+1 dimensions. Using a hamiltonian
lattice formulation we clarify the physical meaning of the zero modes but we do
not find support for speculations on the crucial importance of lower
dimensional fields (zero modes in 1+1 dimension) for the infrared behavior of
QCD in 2+1 or higher dimensions.


title: An angle representation of QCD

abstract:
  For the sake of eliminating gauge variant degrees of freedom we discuss the
way to introduce angular variables in the hamiltonian formulation of QCD. On
the basis of an analysis of Gauss' law constraints a particular choice is made
for the variable transformation from gauge fields to angular field variables.
The resulting formulation is analogous to the one of Bars in terms of corner
variables and it is closely related to the hamiltonian lattice QCD formulation.
Therefore the corner or angle formulation may constitute an useful starting
point for the investigation of the low energy properties of QCD in terms of
gauge invariant degrees of freedom.


title: Fermion damping rate in a hot medium

abstract:
  In principle every excitation acquires a finite lifetime in a hot system.
This nonzero spectral width is calculated self-consistently for massive
fermions coupled to massless scalar, vector and pseudoscalar bosons. It is
shown that the self-consistent summation of the corresponding Fock diagram for
fermions eliminates all infrared divergences although the bosons are not
screened at all. Our solutions for the fermion damping rate are analytical in
the coupling constant, but not analytical in the temperature parameter around
T=0.


title: Local and Nonlocal Defect-Mediated Electroweak Baryogenesis

abstract:
  We consider the effects of particle transport in the topological
defect-mediated electroweak baryogenesis scenarios of Ref. 1. We analyze the
cases of both thin and thick defects and demonstrate an enhancement of the
original mechanism in both cases due to an increased effective volume in which
baryogenesis occurs. This phenomenon is a result of imperfect cancellation
between the baryons and antibaryons produced on opposite faces of the defect.


title: Additional Degrees of Freedom in Skyrmion Motion

abstract:
  We consider the quantization of chiral solitons with baryon number $B>1$.
Classical solitons are obtained within the framework of a variational approach.
From the form of the soliton solution it can be seen that besides the group of
symmetry describing transformations of the configuration as a whole there are
additional symmetries corresponding to internal transformations. Taking into
account the additional degrees of freedom leads to some sort of spin alignment
for light nuclei and gives constraints on their spectra.


title:
Possible Tests for $b \rightarrow s g$ Penguins via Inclusive $K$
  Distributions and Exclusive Processes

abstract:
  We discuss experimental signatures capable of nearly immediate study that
would discern/constrain new physics manifested via enhanced gluonic penguin
decays of the $b$.


title: Semi-leptonic form-factors from lattice qcd

abstract:
  We present results for semi-leptonic form-factors obtained on a statistical
sample of $66$ $32^3 \times 64$ lattices at $\beta = 6.0$ using quenched Wilson
fermions. We find $f_+^{D \to K l \nu}(q^2 = 0) = 0.73 \pm 0.06$, $A_2/A_1({D
\to K^* l \nu}) = 0.72 \pm 0.22$, $V/A_1({D_s \to \phi l \nu}) = 1.91 \pm
0.04$, and $A_2/A_1({D_s \to \phi l \nu}) = 0.68 \pm 0.09$, where the error
estimate includes statistical errors and errors due to extrapolation to $q^2
=0$ and to physical values of $(m_u + m_d)/2$ and $m_s$. The remaining sources
of systematic errors are those due to $O(a)$ discretization errors and those
due to quenching, which our results indicate may be small. We also comment on
the validity of pole-dominance in these form-factors. Source available from
http://nqcd.lanl.gov/Lattice_QCD/papers/dpf94/


title: Supersymmetric SO(10) Simplified

abstract:
  In the context of supersymmetric $SO(10)$ grand unified models, it is shown
that the gauge symmetry breaking as well as a natural doublet--triplet
splitting can be achieved with a minimal Higgs system consisting of a single
adjoint and a pair of vector and spinor multiplets. Such a Higgs spectrum has
been shown to arise in the free fermionic formulation of superstrings. Since
the symmetry breaking mechanism relies on non--renormalizable operators, some
of the Higgs particles of the model turn out to have masses somewhat below the
GUT scale. As a consequence, the unification scale is raised to about $2 \times
10^{17}~GeV$ and sin$^2\theta_W$ is predicted to be slightly larger than the
minimal SUSY--$SU(5)$ value. Including threshold uncertainties, which turn out
to be surprisingly small in the model, we show that sin$^2\theta_W$ prediction
is consistent with experiments.


title:
Radiative Corrections to Quarkonium Decays: From a Model to a Rigorous
  Theory

abstract:
  Most previous calculations of the annihilation decay rates of heavy
quarkonium were based on factorization assumptions that were unproven and, in
some cases, even incorrect. The recent development of a general factorization
formula for heavy quarkonium annihilation rates has provided a rigorous
theoretical foundation for such calculations. The factorization formula is
based on the use of the effective field theory NRQCD to factor the decay rate
into short-distance coefficients that can be calculated in perturbation theory
and long-distance matrix elements that can be computed using lattice
simulations. This approach allows annihilation decay rates to be computed
entirely from first principles.


title:
Perturbative Strong Interaction Corrections to the Heavy Quark
  Semileptonic Decay Rate

abstract:
  We calculate the part of the order $\alpha_s^2$ correction to the
semileptonic heavy quark decay rate proportional to the number of light quark
flavors, and use our result to set the scale for evaluating the strong coupling
in the order $\alpha_s$ term according to the scheme of Brodsky, Lepage and
Mackenzie. Expressing the decay rate in terms of the heavy quark pole mass
$m_Q$, we find the scale for the $\overline{MS}$ strong coupling to be $0.07\,
m_Q$. If the decay rate is expressed in terms of the $\overline{MS}$ heavy
quark mass $\overline m_Q(m_Q)$ then the scale is $0.12\, m_Q$. We use these
results along with the existing calculations for hadronic $\tau$ decay to
calculate the BLM scale for the nonleptonic decay width and the semileptonic
branching ratio. The implications for the value of $|V_{bc}|$ extracted from
the inclusive semileptonic $B$ meson decay rate are discussed.


title: Alpha_s from spectroscopy of psi- and Upsilon-particles in QCD sum rules

abstract:
  In a specific scheme of the QCD sum rules, one gives the estimate of
$\alpha_S\simeq 0.20$ from the data on the masses and leptonic constants of
$\psi$- and $\Upsilon$-particles.


title:
FORTRAN program for a numerical solution of the nonsinglet
  Altarelli-Parisi equation

abstract:
  We investigate a numerical solution of the flavor-nonsinglet Altarelli-Parisi
equation with next-to-leading-order $\alpha_s$ corrections by using Laguerre
polynomials. Expanding a structure function (or a quark distribution) and a
splitting function by the Laguerre polynomials, we reduce an
integrodifferential equation to a summation of finite number of Laguerre
coefficients. We provide a FORTRAN program for Q$^2$ evolution of nonsinglet
structure functions (F$_1$, F$_2$, and F$_3$) and nonsinglet quark
distributions. This is a very effective program with typical running time of a
few seconds on SUN-IPX or on VAX-4000/500. Accurate evolution results are
obtained by taking approximately twenty Laguerre polynomials.


title:
Mixing-Induced CP Violation in the Decay $B_d\to K^0 \bar K^0$ within
  the Standard Model

abstract:
  Recently, flavour $SU(3)$ symmetry of strong interactions has been combined
with certain dynamical assumptions to derive triangle relations among $B$-meson
decay-amplitudes. We show that these relations allow a prediction of the
mixing-induced CP asymmetry $\acpmi(B_d\to K^0\bar K^0)$. Contrary to
statements made in several previous papers, this asymmetry should be
non-vanishing in the Standard Model due to QCD-penguins with internal up- and
charm-quark exchanges and could be as large as $\order(30\%)$. The branching
ratio BR$(B_d\to K^0\bar K^0)$ is expected to be of $\order(10^{-6})$. In the
future, the results presented in this letter should allow interesting tests of
the $SU(3)$ triangle relations and of the Standard Model description of CP
violation.


title:
Higgs Production and Decay via $e^+e^-\rightarrow Z^0 H^0 \rightarrow
  b\bar bW^+W^-$ and Irreducible Backgrounds at the Next Linear Collider

abstract:
  The complete matrix element for $e^+e^-\ar b\bar bW^+W^-$ has been computed
at tree--level and applied to $Z^0H^0$ production followed by $Z^0\ar b\bar b$
and $H^0\ar W^+W^-$, keeping into account all irreducible backgrounds, which
are dominated by \ttb production, at the Next Linear Colliders. We find that,
depending on the center of mass energies and on the search strategies, this
channel can be useful for the study of the parameters of the Standard Model
Higgs boson over the most part of the heavy mass range.


title:
Off-Shell Electromagnetic Form Fators of the Nucleon in Chiral
  Perturbation Theory

abstract:
  We study the electromagnetic form factors of a nucleon in next-to-leading
order chiral perturbation theory (CPT) in the case where one of the nucleons is
off its mass shell. We calculate the leading nonanalytic contributions to
relevant measures for the off-shell dependence in the limited kinematical range
allowed.


title:
$f_1$ Vector Meson Dominance Model for the Strange Axial Form Factor of
  the Nucleon

abstract:
  The axial strange form factor $F^s_A$ of the nucleon is assumed to be
dominated at low momentum transfer by the isoscalar axial vector mesons
$f_1(1285)$ and $f_1(1420)$. The importance of the $a_0\pi N$-triangular vertex
correction is demonstrated.


title: The production of jets from quasi real photons in \epem collisions

abstract:
  We consider the production of jets in photon-photon collisions beyond the
leading logarithm approximation. Theoretical uncertainties as well as
uncertainties due to the virtuality of the initial photons are discussed in
detail. The comparison with TOPAZ data is performed and good agreement is found
between experiment and theory. It is expected that future high precision
TRISTAN data will constrain the non-perturbative component of the photon
structure function.


title: The Strongly Interacting Electroweak Phase Transition

abstract:
  A quantitative discussion of nonperturbative effects for the high temperature
electroweak phase transition is presented. We propose a method for the
computation of the temperature dependent effective scalar potential that takes
into account the running of the effective gauge coupling. Compared to
perturbation theory we find a moderate decrease of the critical temperature and
an important change in the strength of the first order transition. We conclude
that perturbation theory gives a misleading picture of the dynamics of the
transition.


title: On the photoproduction of jets at HERA

abstract:
  We discuss the inclusive jet production at HERA in the next-to-leading
logarithm approximation. Theoretical uncertainties are considered in some
details. We show the importance of the jet rapidity distribution to constrain
the parton densities in the photon. A comparison is made with the recent H1
data.


title:
Isospin Mass Splittings and the $\ms$ Corrections in the Semibosonized
  SU(3)-NJL-Model

abstract:
  The mass splittings of hyperons including the isospin splittings are
calculated with $O(\ms^2)$ and $O(\ms \dm)$ accuracy respectively within the
semibosonized SU(3)-NJL model. The pattern of the isospin splittings is not
spoiled by the terms of the order $O(\ms \dm)$, and both splittings between the
different isospin multiplets and within the same multiplet are well reproduced
for acceptable values of $\ms$ and $\dm$.


title: The $(0^+,1^+)$ heavy meson multiplet in an extended NJL model

abstract:
  In this letter we reconsider the previously given description of heavy mesons
within a bosonized extended NJL model that combines heavy quark and chiral
symmetry. In that work the naive gradient expansion of the quark determinant
was used, which satisfactorily works in the light sector but does not
adequately describe the heavy $(0^+,1^+)$ mesons. By investigating the exact
momentum dependence of the quark loop we demonstrate that the naive gradient
expansion in the heavy sector is not the right method to treat the unphysical
$q\bar{q}$--thresholds which would be absent in confining theories. We propose
a modified gradient expansion which adequately extrapolates from the
low--momentum region beyond threshold. This expansion gives a satisfactory
description even of the $(0^+,1^+)$ heavy mesons whose masses are significantly
above threshold.


title: Proton spin content from skyrmions

abstract:
  It is well known that in lowest order the skyrmion model of the nucleon gives
vanishing spin content. With new data indicating a proton spin content
$\Delta\Sigma = 0.22\pm 0.14,$ it is an increasing challenge to find ways in
which the skyrmion can move away from the null result. We show here that a
particular term in the skyrmion lagrangian in SU(3) involving six derivatives
of the field can, with plausible parameters, yield a spin content consistent
with present experiment.


title:
Studying the Quark Antiquark Force with Inelastic Pion Electron
  Scattering

abstract:
  The concept of studying the internal structure of mesons is explored. Mesons,
which are in principle two body quark antiquark interactions, may be much
easier to understand than the nucleon. Measurements of the inelastic form
factors to specific final states may permit careful direct studies of various
components of the strong force. For example by looking at vector meson final
states the spin flip amplitude can be isolated. Technical difficulties involved
in a realistic experiment are examined. Experiments to some final states such
as $\rho$, $K^*$ and $a_{0}$ are practical today.


title:
Event Rates in Dark Matter Detectors For Neutralinos Including
  Constraints From The $b\rightarrow s\gamma$ Decay

abstract:
  Event rates for dark matter detectors in neutralino--nucleus scattering are
studied for supergravity unified models, including the constraint arising from
the $b\rightarrow s\gamma$ experiment. The recent experimental measurement of
this decay by the CLEO Collaboration leads to strong constraints on the SUSY
particle spectrum,and also significantly affects the event rates in dark matter
detectors. The analysis given here uses the accurate method for the computation
of the relic density and leads to a dip in the event rate when the neutralino
mass is $\sim M_Z/2$ due to the $Z$-pole, and similar results hold when the
neutralino mass is $\sim m_h/2$ due to the Higgs pole . Implication of these
results for dark matter detectors are discussed.


title: Scattering off an SO(10) cosmic string

abstract:
  The scattering of fermions from the abelian string arising during the phase
transition $SO(10) \rightarrow SU(5) \times Z_2$ induced by the Higgs in the
126 representation is studied. Elastic cross-sections and baryon number
violating cross-sections due to the coupling to gauge fields in the core of the
string are computed by both a first quantised method and a perturbative second
quantised method. The elastic cross-sections are found to be Aharonov-Bohm
type. However, there is a marked asymmetry between the scattering
cross-sections for left and right handed fields. The catalysis cross-sections
are small, depending on the grand unified scale. If cosmic strings were
observed our results could help tie down the underlying gauge group.


title: Considerations Concerning the QCD Corrections to $\Delta\rho$

abstract:
  Using recent results of Avdeev et al. and an expansion for $\mu_t/\mms$
($M_t$ is the pole mass and $\mu_t\equiv \hat{m_t}(\mu_t)$ ), it is shown that
when deltarho is expressed in terms of $\hat{m_t}^2(M_t)$, the QCD correction
is only $(2-3)\times 10^{-3}$ in the NLO approximation. As a consequence, in
terms of $M_t^2$ the correction to $\dr$ is almost entirely contained in
$\mmss/M_t^2$, a pure QCD effect.
  The latter is studied using various optimization procedures, and the results
compared with the expansion proposed by Avdeev et al.. Implications for \ew
physics are discussed. Threshold effects are analyzed on the basis of a simple
sum rule.


title: Technicolor and Precision Tests of the Electroweak Interactions

abstract:
  Precision electroweak measurements have been claimed to eliminate almost all
models of technicolor. We show that the assumptions made to calculate the
oblique parameters $S$,$T$,$U$ apply to QCD--like technicolor models which were
ruled out long ago on much firmer grounds. These assumptions are invalid in
modern ``walking'' technicolor models.


title: Top-Production and Flavor Physics--The Talk

abstract:
  Because of the top quark's very large mass, about 175~GeV, it now provides
the best window into flavor physics. Thus, pair--production of top quarks at
the Tevatron Collider is the most incisive probe of this physics until the
Large Hadron Collider turns on in the next century. In this talk I discuss how
moments of the $\ttb$ invariant mass distribution can be used to distinguish
among standard and alternative mechanisms of $\ttb$ production.


title:
Theoretical Uncertainties in the Extraction of $|V_{cb}|$ from $\bar
  B\to D^*\ell\,\bar\nu$ Decays near Zero Recoil

abstract:
  I discuss the theoretical uncertainties in the extraction of $|\,V_{cb}|$
from a measurement of the $\bar B\to D^*\ell\,\bar\nu$ decay rate close to zero
recoil. In particular, I combine previous estimates of the $1/m_Q^2$
corrections to the normalization of the hadronic form factor at zero recoil
with sum rules derived by Shifman {\it et al}.\ to obtain a new prediction with
less uncertainty. I also give a prediction for the slope of the form factor
$\widehat\xi(w)$ at zero recoil: $\widehat\varrho^2=0.7\pm 0.2$. Using the most
recent experimental results, I obtain the model-independent value
$|\,V_{cb}|=0.0395\pm 0.0030$.


title: Chiral Anomaly Tests

abstract:
  For the gamma-pion interaction, the perturbative expansion of the effective
chiral Lagrangian (chi-PT) can be limited to terms quartic in momenta and
masses (O(p4)), or to higher order. The abnormal intrinsic parity (chiral
anomaly) component of the lagrangian leads to interesting predictions for the
processes pi0 -----> 2 gamma and gamma ----->3 pi. These are described by the
amplitudes F_{pi} and F_{3pi}, respectively. We demonstrate that the O(p4)
value of F_{3pi} disagrees with existing data, while the O(p6) value is nearly
consistent. We describe how Fermilab experiment E781 can get improved data for
tests of the chiral anomaly.


title:
Effective Field Theory Approach to Parton-Hadron Conversion in High
  Energy QCD Processes

abstract:
  A QCD based effective action is constructed to describe the dynamics of
confinement and symmetry breaking in the process of parton-hadron conversion.
The deconfined quark and gluon degrees of freedom of the perturbative QCD
vacuum are coupled to color singlet collective fields representing the
non-perturbative vacuum with broken scale and chiral symmetry. The effective
action recovers QCD with its scale and chiral symmetry properties at short
space-time distances, but yields at large distances (r > 1 fm) to the formation
of symmetry breaking gluon and quark condensates. The approach is applied to
the evolution of a fragmenting $q\bar q$ pair with its generated gluon
distribution, starting from a large hard scale $Q^2$. The modification of the
gluon distribution arising from the coupling to the non-perturbative collective
field results eventually in a complete condensation of gluons. Color flux tube
configurations of the gluons in between the $q\bar q$ pair are obtained as
solutions of the equations of motion. With reasonable parameter choice, the
associated energy per unit length (string tension) comes out $\simeq 1$ GeV/fm,
consistent with common estimates.


title:
QCD Factors a1 and a2 Beyond Leading Logarithms Versus Factorization in
  Non-Leptonic Heavy Meson Decays

abstract:
  We calculate the QCD factors $a_1$ and $a_2$, entering the tests of
factorization in non-leptonic heavy meson decays, beyond the leading
logarithmic approximation in three renormalization schemes (NDR, HV, DRED). We
investigate their $\mu$--dependence and the renormalization scheme dependence.
We point out that $a_1$ for B-decays depends very weakly on $\Lms$, $\mu$ and
the choice of the renormalization scheme. For $\Lms^{(5)}=225\pm85~MeV$ and
$4~GeV\leq\mu\leq 8~GeV$ we find $a_1=1.01\pm0.02$ in accordance with
phenomenology. The $\Lms$, $\mu$ and scheme dependences of $a_2$ are on the
other hand sizable. Interestingly, for the NDR scheme we find
$a_2^{NDR}=0.20\pm0.05$, in the ball park of recent phenomenological results
and substantially larger than leading order estimates. However
$a_2^{HV}=0.16\pm0.05$ and $a_2^{DRED}=0.15\pm0.05$. Implications of these
findings for the tests of factorization in B-decays and D-decays are critically
discussed.


title:
New Neutral Gauge Bosons and New Heavy Fermions in the Light of the New
  LEP Data

abstract:
  We derive limits on a class of new physics effects that are naturally present
in grand unified theories based on extended gauge groups, and in particular in
$E_6$ and $SO(10)$ models. We concentrate on $i$) the effects of the mixing of
new neutral gauge bosons with the standard $Z_0$; $ii$) the effects of a mixing
of the known fermions with new heavy states. We perform a global analysis
including all the LEP data on the $Z$ decay widths and asymmetries collected
until 1993, the SLC measurement of the left--right asymmetry, the measurement
of the $W$ boson mass, various charged current constraints, and the low energy
neutral current experiments. We use a top mass value in the range announced by
CDF. We derive limits on the $Z_0$--$Z_1$ mixing, which are always $\lsim 0.01$
and are at the level of a few {\it per mille} if some specific model is
assumed. Model-dependent theoretical relations between the mixing and the mass
of the new gauge boson in most cases require $M_{Z'} > 1\,$TeV. Limits on
light--heavy fermion mixings are also largely improved with respect to previous
analyses, and are particularly relevant for a class of models that we discuss.


title: Low x phenomena

abstract:
  We review recent developments in the application of perturbative QCD to
phenomena at small x.


title: Summary of Top Quark Physics

abstract:
  I briefly review standard top quark physics at hadron colliders and summarize
the contributions to this conference. The possibility of new mechanisms for
$t\bar{t}$ production are also discussed.


title: Extraction of $V_{ub}$ from the Decay $B\to \pi l \nu$

abstract:
  We develop the perturbative QCD formalism including Sudakov effects for
semi-leptonic $B$ meson decays. We evaluate the differential decay rate of
$B\to \pi l \nu$, and find that the perturbative calculation is reliable for
the energy fraction of the pion above 0.3. Combining predictions from the soft
pion theorems, we extract the value of the matrix element $|V_{ub}|$ which is
roughly $2.7\times 10^{-3}$.


title:
${\cal O}(\alpha\as \ln m_t^2)$ Non-Universal Corrections to the Decay
  Rate $\Gamma(Z\rightarrow b\bar{b})$

abstract:
  The partial decay rate $\Gamma(Z\to b\bar{b})$ is significantly influenced by
the mass of the top quark due to electroweak radiative corrections. The leading
$\sim m_t^2$ and the next-to-leading contribution $\sim \ln m_t^2$ are known to
be numerically of similar size. In this work we calculate the QCD corrections
to the logarithmic correction using the heavy top mass expansion. The ${\cal O}
(\alpha\as \ln m_t^2)$ corrections are of the same order as the QCD corrections
to the quadratic top mass term, but of different sign.


title:
Z -> b\bar{b} Versus Dynamical Electroweak Symmetry Breaking involving
  the Top Quark

abstract:
  In models of dynamical electroweak symmetry breaking which sensitively
involve the third generation, such as top quark condensation, the effects of
the new dynamics can show up experimentally in Z->b\bar{b}. We compare the
sensitivity of Z->b\bar{b} and top quark production at the Tevatron to models
of the new physics. Z->b\bar{b} is a relatively more sensitive probe to new
strongly coupled U(1) gauge bosons, while it is generally less sensitive a
probe to new physics involving color octet gauge bosons as is top quark
production itself. Nonetheless, to accomodate a significant excess in
Z->b\bar{b} requires choosing model parameters that may be ruled out within run
I(b) at the Tevatron.


title:
Perturbative QCD Fragmentation Functions as a Model for Heavy-Quark
  Fragmentation

abstract:
  The perturbative QCD fragmentation functions for a heavy quark to fragment
into heavy-light mesons are studied in the heavy-quark limit. The fragmentation
functions for S-wave pseudoscalar and vector mesons are calculated to
next-to-leading order in the heavy-quark mass expansion using the methods of
heavy-quark effective theory. The results agree with the $m_b\to \infty$ limit
of the perturbative QCD fragmentation functions for $\bar b$ into $B_c$ and
$B_c^*$. We discuss the application of the perturbative QCD fragmentation
functions as a model for the fragmentation of heavy quarks into heavy-light
mesons. Using this model, we predict the fraction $P_{V}$ of heavy-light mesons
that are produced in the vector meson state as functions of the longitudinal
momentum fraction $z$ and the transverse momentum relative to the jet axis. The
fraction $P_V$ is predicted to vary from about 1/2 at small $z$ to almost 3/4
near $z=1$.


title: Determination of V_ub at the Z-boson resonance

abstract:
  We show that the observation of energetic charged leptons from semileptonic
$b$ becays at the LEP and SLC $Z$--boson factories offers a unique opportunity
to measure the quark mixing matrix element $V_{ub}$. We present various
distributions of the $b$ decay products to show that the $b \to u$ decays can
be cleanly separated from the $b \to c$ decays, with a signal of $O(100)$
events per million $Z$ bosons produced.


title:
Isolating the Penguin-diagram Contribution to $CP$ Violation in
  $B^{0}_{d}$ vs $\bar{B}^{0}_{d}\rightarrow \pi^{+}\pi^{-}$

abstract:
  A reliable prediction for $CP$ violation in $B^{0}_{d}$ vs
$\bar{B}^{0}_{d}\rightarrow \pi^{+}\pi^{-}$ suffers from the penguin-diagram
induced uncertainty. With the help of SU(3) relations, we show that both the
magnitude and strong phase shift of the penguin amplitude can be approximately
determined only from the branching ratios of $B^{0}_{d}\rightarrow
\pi^{+}\pi^{-}$, $B^{0}_{d}\rightarrow K^{+}\pi^{-}$, and $B^{+}_{u}\rightarrow
K^{0}\pi^{+}$.


title: Is baryon number violated when electroweak strings intercommute?

abstract:
  We reexamine the self-helicity and the intercommutation of electroweak
strings. A plausible argument for baryon number conservation when electroweak
strings intercommute is presented. The connection between a segment of
electroweak strings and a sphaleron is also discussed.


title: Vector boson pair production in e-e- collisions with polarized beams

abstract:
  The $W$-boson pair production in $e^-e^-$ collisions with polarized beams is
investigated. The helicity amplitudes are derived for general couplings and the
conditions for a good high-energy behaviour of the cross-section are given. The
results are applied to the heavy vector boson production in the context of the
left-right symmetric model. The Ward identities and the equivalence theorem are
also discussed.


title: Could Vector Leptoquarks be Rather Light?

abstract:
  A possible Standard Model extension of the Pati-Salam type with a lepton
number as the fourth color is reexamined. A new type of mixing in the
interaction of the $SU(4)_V$--leptoquark with quarks and leptons is shown to be
required. An additional arbitrariness of the mixing parameters could allow to
decrease noticeably the lower bound on the leptoquark mass $M_X$ originated
from the $\pi$ and $K$ decays and the $\mu e$ conversion. The only mixing
independent bound emerging from the cosmological limit on the $\pi^0
\rightarrow \nu \bar{\nu}$ decay width is $M_X > 18~TeV$.


title: Order $\alpha^4 (m/M) R_{\infty}$ corrections to hydrogen P levels

abstract:
  The order $\alpha^4 (m/M) R_{\infty}$ shift of hydrogen P levels is found.
The corrections are predominantly of relativistic origin. Our approach is a
straightforward extension of that developed and applied by us previously to
positronium P levels. The corrections to the Lamb shift in hydrogen constitute
numerically \delta E(2 P_{1/2})=0.55 kHz, \delta E(2 P_{3/2}) =0.44 kHz.


title: NN,N\Delta Couplings and the Quark Model

abstract:
  We examine mass-corrected SU(6) symmetry predictions in the quark model
relating vector, axial-vector and strong NN and N\Delta couplings, and
demonstrate that the experimental N\Delta value is significantly higher than
predicted in each case. Nevertheless the Goldberger-Treiman relation is
satisfied in both sectors. Possible origins of the discrepancy of the quark
model predictions with experiment are discussed.


title: Minimal Family Unification

abstract:
  Absract It is proposed that there exist, within a new $SU(2)^{'}$, a gauged
discrete group $Q_6$ (the order 12 double dihedral group) acting as a family
symmetry. This nonabelian finite group can explain hierarchical features of
families, using an assignment for quarks and leptons dictated by the
requirements of anomaly cancellation and of no additional quarks.


title: Symmetry Tests and Standard Model Backgrounds

abstract:
  Symmetry tests provide an important probe for the structure of elementary
particle interactions and for the validity of the standard model. However, it
is pointed out that in the interpretation of such experiments one must keep in
mind that in many cases apparent "violations" of such tests are actually the
result of ordinary effects within the standard model.


title:
EXCALIBUR -- a Monte Carlo program to evaluate all four fermion
  processes at LEP 200 and beyond

abstract:
  A Monte Carlo program is presented that computes all four fermion processes
in $e^+ e^-$ annihilation. QED initial state corrections and QCD contributions
are included. Fermions are taken to be massless, allowing a very fast
evaluation of the matrix element. A systematic, modular and self-optimizing
strategy has been adopted for the Monte Carlo integration, that serves also as
an example for further event generators in high energy particle physics.


title: Bose-Einstein Correlations for Longitudinally Expanding Finite Systems

abstract:
  Bose-Einstein correlations and momentum distributions are calculated for
longitudinally expanding systems, like jets or high energy heavy ion collisions
with light projectiles. The expansion generates a thermal length-scale in the
longitudinal direction, and the geometrical length-scale is also finite. The
Bose-Einstein correlation functions are dominated by the smaller while the
invariant momentum distribution by the longer of the two longitudinal
length-scales.


title: Summary of Heavy Ion Theory

abstract:
  Can we study hot QCD using nuclear collisions? Can we learn about metallic
hydrogen from the impact of comet Shoemaker-Levy 9 on Jupiter? The answer to
both questions may surprise you! I summarize progress in relativistic heavy ion
theory reported at DPF `94 in the parallel sessions.


title:
Naturally Light Higgs Doublets in the Supersymmetric Grand Unified
  Theories with Dynamical Symmetry Breaking

abstract:
  We construct a supersymmetric grand unified model in which a dynamical
symmetry breaking of SU(5)$_{GUT}$ generates large masses for color-triplet
Higgs multiplets while keeping SU(2)$_L$-doublet Higgs multiplets naturally
light. The vanishing masses for the Higgs doublets are guaranteed by the
Peccei-Quinn symmetry. We also show that the Peccei-Quinn symmetry suppresses
the dangerous dimension 5 operators for the nucleon decay.


title: Simple Non-Abelian Finite Flavor Groups and Fermion Masses

abstract:
  The use of nonabelian discrete groups G as family symmetries is discussed in
detail. Out of all such groups up to order g = 31, the most appealing
candidates are two subgroups of SU(2): the dicyclic [double dihedral] group G =
$Q_6 ={ }^{(d)}D_3$ ( g = 12 ) and the double tetrahedral group $^{(d)}T =
Q_4\tilde{\times}Z_3$ ( g = 24 ). Both can allow a hierarchy $t > b, \tau > c >
s, \mu > u, d, e$. The top quark is uniquely allowed to have a G symmetric
mass. Sequential breaking of G and radiative corrections give the smaller
masses. Anomaly freedom for gauging $G \subset SU(2)$ is a strong constraint in
assignment of fermions to representations of G.


title: The Third Family is Different

abstract:
  It now appears phenomenologically that the third family of fundamental
fermions may be essentially different fron the first two. Particularly the high
value (174GeV?) of the top quark mass suggests a special role. In the standard
model all three families are treated similarly [becoming exactly the same at
asymptotically high energies] so we need to extend the model to accommodate the
goal of a really different third family. In this article I describe not one but
two such viable extensions, quite different one from another. The first is the
331 model which predicts dileptonic gauge bosons. The second is the $Q_6$ model
which predicts additional leptons between 50 and 200 GeV. One expects there are
many other models of this general type characterized by the prediction of new
particles at accessible masses. Supersymmetrization will not be discussed here.


title: Higgs signals modified by singlet scalars

abstract:
  The influence of massless scalar singlets on Higgs signals is discussed. It
is shown, that in the case of strong interactions between the Higgs boson and
the singlet fields, signals could be suppressed in such a way, that detection
of the Higgs boson becomes impossible.


title:
Exact $m_{quark}\neq 0$ Condensates in $QCD_{1+1}(N_C\rightarrow
  \infty)$

abstract:
  In the limit of an infinite number of colors, we derive an analytic
expression for the quark condensate in $QCD_{1+1}$ as a function of the quark
mass and the gauge coupling constant. For zero quark mass, a nonvanishing quark
condensate is obtained. Nevertheless, we prove that there is no phase
transition as a function of the quark mass. It is furthermore shown that the
expansion of $\langle 0 | \overline{\psi}\psi |0\rangle$ in the gauge coupling
has zero radius of convergence but that the perturbation series is Borel
summable with finite radius of convergence. The nonanalytic behavior $\langle 0
| \overline{\psi}\psi |0\rangle \stackrel{m_q\rightarrow0}{\sim} - N_C
\sqrt{G^2}$ can only be obtained by summing the perturbation series to infinite
order.


title:
$Z$ POLARIZATION IN $pp\rightarrow ZZ\rightarrow \ell^+\ell^-\nu
  \bar{\nu}$ AT THE LHC

abstract:
  We evaluate the feasibility of measuring the $Z$ polarization from a heavy
Higgs signal in the decay channel $H\rightarrow ZZ \rightarrow \ell^+
\ell^-\nu\bar{\nu}$. Including gluon fusion production of the Higgs, continuum
production of $Z$ pairs and the QCD background of single $Z$ production with a
missing jet, we find that the average value of a new variable to measure the
$Z$ polarization, as a function of transverse mass, will demonstrate the
existence of a Higgs boson for heavy Higgs masses up to 800 GeV at the LHC with
an integrated luminosity of 10$^5$ pb$^{-1}$.


title: The Strange Quark Mass from QCD Sum Rules

abstract:
  The strange quark mass is calculated from QCD sum rules for the divergence of
the vector as well as axial-vector current in the next-next-to-leading
logarithmic approximation. The determination for the divergence of the
axial-vector current is found to be unreliable due to large uncertainties in
the hadronic parametrisation of the two-point function.
  From the sum rule for the divergence of the vector current, we obtain a value
of $m_s\equiv\mb_s(1\,\gev)=189\pm32\,\mev$, where the error is dominated by
the unknown perturbative ${\cal O}(\alpha_s^3)$ correction. Assuming a
continued geometric growth of the perturbation series, we find
$m_s=178\pm18\,\mev$. Using both determinations of $m_s$, together with
quark-mass ratios from chiral perturbation theory, we also give estimates of
the light quark masses $m_u$ and $m_d$.


title: New Electroweak Instanton and Possible Breakdown of Unitarity

abstract:
  Potential implications of a new constrained instanton solution in the
electroweak standard model are discussed. Notably, there may be a
non-perturbative unitarity violating contribution to the total cross-section at
high collision energies.


title:
What is the lightest excited state of the strongly selfcoupled Higgs
  field?

abstract:
  We argue for the existence of an upper bound $m_*$ on the Higgs mass at which
the lowest excited state of the Higgs field ceases to be the conventional plane
wave. An explicit construction of an alternative nonperturbative state is
discussed. This excitation is spatially localized. The field fluctuations
inside the localization region are large. The energy of the excitation is
smaller than the mass of the plane wave state $m$ at $m>m_*$. An approximate
value of $m_*$ is found to be $m_* \approx 4.75$ times the vacuum expectation
value. This is an upper bound at the tree level.


title: Lattice results for Heavy-Light matrix elements

abstract:
  We review recent lattice computations relevant for $D$ and $B$ decays. Decay
constants $f_{D,D_s}$, $f_{B,B_s}$, $D\rightarrow K (K^*)$, $B\rightarrow \pi ,
\rho$ semi-leptonic form factors together with the slope of the Isgur-Wise
function calculations are presented. Some recent results of $B\rightarrow K^*
\gamma$ form factors will be given. $1/M$ corrections to the asymptotic scaling
laws are discussed.


title: The Free Energy of Hot QED at Three and Half Loops

abstract:
  The computation of order $e^4$ and $e^5$ contributions to the pressure of
massless quantum electrodynamics at a temperature $T$ is overviewed.


title:
QCD corrections to large-$m_t$ electroweak effects in $\Delta r$. An
  effective field theory point of view

abstract:
  By using effective field theory techniques for the standard model, we discuss
the issue of what $\mu$ scale is the appropriate one in the QCD corrections to
the large-$\mt$ electroweak contributions to $\Delta r$. This needs the
construction of an effective field theory below the top quark. We argue that,
while matching corrections do verify the simple prescription of taking $\mu
\simeq \mt$ in $\a(\m)$, logarithmic (i.e. $\sim \log \mt$) corrections do not,
and require the use of the running $\a(\mu)$ in the corresponding
renormalization group equation.


title: Semileptonic B Meson Decays and Interfering Amplitudes

abstract:
  Consequences of the interference between external and internal spectator
amplitudes for the lifetimes and semileptonic decay fractions of $B^0$ and
$B^+$ mesons are discussed. Extrapolating from the constructive interference
observed in 11 exclusive hadronic $B$ decays we find an inclusive semileptonic
decay fraction of $(11.2 \pm 0.5 \pm 1.7)$\%, significantly closer to the
experimental results than previous predictions.


title: Supersymmetric Unification: a mini-review of recent developments

abstract: Some recent results in supersymmetric grand unified theories are reviewed.


title: Pion Multiplicity Distribution in Proton-Antiproton Annihilation at Rest

abstract:
  The pion multiplicity distribution is widely believed to reflect the
statistical aspects of $\bar{p}p$ annihilation at rest. We try to reproduce it
in a grand canonical picture with explicit conservation of electric charge,
isospin, total angular momentum, and the parity quantum numbers $P$, $C$, and
$G$ via the projection operator formalism. Bose statistics is found to be
non-negligible, particularly in fixing the interaction volume. The calculated
pion multiplicity distribution for $\left\langle n_{\pi} \right\rangle = 5$
turns out to depend strongly on the conservation of the angular momentum and
connected quantum numbers, as well as on the spin state occupation in S-wave
annihilation. However, the empirical Gaussian pion multiplicity distribution
cannot be reproduced. This calls in question either the statistical ansatz or
the rather old data themselves.


title: Non-perturbative methods

abstract:
  The current theoretical understanding of processes involving many weakly
interacting bosons in the Standard Model and in model theories is discussed. In
particular, such processes are associated with the baryon and lepton number
violation in the Standard Model. The most interesting domain where the
multiplicity of bosons is larger than the inverse of small coupling constant is
beyond the scope of perturbation theory and requires a non-perturbative
analysis.


title: How to Measure $m_t$: A Brief Overview

abstract:
  This talk is an overview of prospects for measuring the top mass $m_t$ at
present and future colliders. Methods for extracting $m_t$ appropriate to
experiments at the Tevatron, Large Hadron Collider, and Next Linear Collider
are discussed, with examples given for each. Sources of systematic
uncertainties specific to each method and experiment are identified.


title: Expanding Protons seen by HERA

abstract:
  We show that the rising total photoproduction cross section recently observed
at HERA is entirely consistant with the impact-picture in the theory of
expanding protons which was proposed more than twenty years ago. More accurate
data, which is expected to be forthcoming soon, will give this prediction a
stringent test.


title: Supersymmetric Grand Unified Theories And Yukawa Unification

abstract:
  Talk given at Frontiers in Particle Physics Conference, Cargese. In this
paper, I provide some motivation for supersymmetric grand unified theories,
briefly explain an extension of the standard model based on them and present a
calculation performed using certain properties of some SUSY GUTs to constrain
the available parameter space.


title:
Semileptonic $B\to D^{(*)}l\nu$ decays, the slope of Isgur-Wise function
  and $|V_{bc}|$ value in potential quark model

abstract:
  The modification of the naive potential model of the heavy meson is
considered on the basis of the single-time prescription for the quark-meson
form factor and the covariant choice of the quatk relative momentum. The
application of the model to the description of the semileptonic decays of the
beauty meson allows one to determine the Isgur-Wise function slope
$\rho^2\simeq 1.25$ and to extract the value $|V_{bc}|= 0.038\pm 0.003$ from
the experimental data.


title: Model Independent Features of the Two-Particle Correlation Function

abstract:
  The Hanbury-Brown Twiss correlation function for two identical particles is
studied for systems with cylindrical symmetry. Its shape for small values of
the relative momentum is derived in a model independent way. In addition to the
usual quadratic ``side'', ``out'' and ``longitudinal'' terms in the exponent of
the correlator, a previously neglected ``out-longitudinal'' cross term is found
and discussed. The model-independent expressions for the size parameters of the
HBT correlation function are interpreted as lengths of homogeneity of the
source, in distinction to its purely geometrical size. They are evaluated
analytically and numerically for two specific thermal models featuring
collective transverse and longitudinal flow. The analytic expressions derived
allow one to establish qualitatively important connections between the
space-time features of the source and the shape of the correlation function.
New ways of parametrizing the correlation function and a new approach to the
measurement of the duration of the emission process are suggested.


title: Cosmological Constraints on Perturbative Supersymmetry Breaking

abstract:
  We discuss the cosmology of string models with perturbative supersymmetry
breaking at a scale of ${\cal O}$(TeV). Such models exhibit Kaluza-Klein like
spectra and contain unstable massive gravitinos/gravitons. We find that
considerations of primordial nucleosynthesis constrain the maximum temperature
following inflation to be not much larger than the supersymmetry breaking
scale. This imposes conflicting requirements on the scalar field driving
inflation, making it rather difficult to construct a consistent cosmological
history for such models.


title: Spin-dependent Parton Distributions

abstract:
  We perform a global leading-order QCD fit to recent polarized structure
function data in order to extract a consistent set of spin-dependent parton
distributions. Assuming that there is no significant intrinsic polarization of
the quark sea, the data are consistent with a modest amount of the proton's
spin carried by the gluon, although the shape of the gluon distribution is not
well constrained. We show how inelastic $J/\psi$ production in polarized
photon-hadron scattering can, in principle, provide definitive information on
the shape of the gluon distribution. (Talk presented by W.J.Stirling at the
27th International Conference on High Energy Physics, Glasgow, July 1994)


title:
Perturbative QCD Fragmentation Functions as a Phenomenological Model for
  Charm/Bottom Fragmentation

abstract:
  The perturbative QCD fragmentation functions can be applied
phenomenologically as a model for charm and bottom quark fragmentation into
heavy-light mesons. The predictions by this model on the observables $P_V$ and
$\langle z \rangle$ for $D-D^*$ and $B-B^*$ systems are compared with
experimental data.


title:
S-Wave and P-Wave $B_c$ Meson Production at Hadron Colliders by Heavy
  Quark Fragmentation

abstract:
  We compute model-independently the production rates and transverse momentum
spectra for the $B_c$ mesons in various spin-orbital states ($n\,^1S_0$,
$n\,^3S_1$, $n\,^1P_1$, and $n\,^3P_J\,(J=0,1,2)$ ) at hadron colliders via the
direct fragmentation of the bottom antiquark and via the
Altarelli-Parisi-induced gluon fragmentation. Since all the radially and
orbitally excited states below the $BD$ flavor threshold will decay, either
electromagnetically, hadronically, or a combination of both, into the
pseudoscalar ground state $1\,^1S_0$, they all contribute significantly to the
inclusive $B_c$ meson production.


title:
Further ways to distinguish single-lepton top quark signals from
  background at the Tevatron

abstract:
  Further kinematical variables are suggested, in which to compare the putative
leptonic $W$ plus 4-jet top quark signal with the QCD background. We show that
the lepton rapidity asymmetry, the $p_T$-ranking of the tagged $b$-jet, the
double-tag probability, the reconstructed $t+\bar t$ invariant mass, and the
lepton energy in the parent top quark rest-frame, all display interesting
differences between signal and background.


title: Distinguishing $B$ and $\overline B$ Hadrons

abstract:
  Distinguishing the flavor of $B$ and $\overline B$ hadrons is critical in
studies of CP-violation, $B^0 -\overline{B^0}$ mixing, and the underlying
$b$-decay mechanisms. Methods of $b$ ``flavor tagging" are broadly divided into
``opposite $b$" tagging and self-tagging of the signal $b$ hadron. The former,
while understood, has the perceived drawback of low efficiency. The latter,
while having the potential for an order of magnitude higher efficiency, has yet
to be demonstrated for neutral $B$ hadrons. In this article we review opposite
$b$ tagging in light of methods whose efficacy has only recently been
demonstrated or suggested. In addition, we recommend a number of tagging
methods for the opposite $b$ including: $K^{*0}$ and $K^{*\pm}$ with large
inclusive yields of 15\% and 18\%; $\overline \Lambda$ and $\overline
{\Lambda}p $; partially reconstructed charmed hadrons; sophisticated jet charge
techniques, etc. We also recommend the use of self-tagging for the $opposite$
$b$ hadron. Such an inversion of self-tagging could conceivably increase the
efficiency of opposite $b$ tagging and even mitigate the effects of neutral $B$
mixing. Self-tagging of the signal hadron, when possible, could be used either
by itself or to confirm the result from the opposite $b$ tag. We suggest that
all methods be weighted by their dilutions and combined to yield efficient
tagging. For a given detector, this requires that the dilution of each tag be
well measured. We therefore review the determination of the dilution $D_T$ for
a general tag $T$ in some detail. Finally, we briefly consider $B$ sector and
suggest a number of exclusive modes which can be combined for higher statistics
probes of the unitarity angles. While ambitious from an experimental
perspective, the program of flavor identification outlined here has the
potential to yield important fundamental results in the near future.


title: Light mesons production at the Tevatron to next-to-leading order

abstract:
  Inclusive production of light mesons ($\pi^0$, $\eta$, $\pi^{\pm}$, $K^{\pm}$
) at the Tevatron is considered in QCD to next-to-leading order in the
formalism of fragmentation functions. We present various distributions of
phenomenological interest, along with a new set of $K$ mesons fragmentation
functions.


title:
Detection of Minimal Supersymmetric Model Higgs Bosons in $\gam\gam$
  Collisions: Influence of SUSY Decay Modes

abstract:
  We demonstrate that supersymmetric decay modes of the neutral Higgs bosons of
the MSSM could well make their detection extremely difficult when produced
singly in $\gam\gam$ collisions at a back-scattered laser beam facility.


title: $|V_{cb}|$ from OPE Sum Rules for Heavy Flavor Transitions

abstract:
  Recent progress in determination of $|V_{cb}|$ within the heavy quark
expansion is reported. Both exclusive and inclusive approaches are discussed.


title: Theory of Weak Inclusive Decays and Lifetimes of Heavy Hadrons

abstract:
  The theory of preasymptotic effects in inclusive decays of heavy flavors is
briefly reviewed.


title: Sphalerons in the Standard Model with a real Higgs singlet

abstract:
  Sphaleron energies within the standard model with a real Higgs singlet added
on are calculated. The coupled non-linear equations of motion are numerically
solved and the sphaleron energy evaluated for a set of parameters in the Higgs
potential. I find a small difference in the sphaleron energy compared to the
standard model. A slightly stronger constraint on the strength of the first
order phase transition thus results for this model.


title: The Aligned $SU(5) \times U(1)^2$ Model

abstract:
  In Calabi-Yau string compactification, it is pointed out that there exists a
new type of $SU(5) \times U(1)^2$ model (the aligned $SU(5) \times U(1)^2$
model) in which the $SU(5)$ differs from the standard $SU(5)$ and also from the
flipped $SU(5)$. With the aid of the discrete symmetry suggested from Gepner
model, we construct a simple and phenomenologically interesting
three-generation model with the aligned $SU(5) \times U(1)^2$ gauge symmetry.
The triplet-doublet splitting problem can be solved. It is also found that
there is a realistic solution for solar neutrino problem and for the $\mu
$-problem. At low energies this model is in accord with the minimal
supersymmetric standard model except for the existence of singlet fields with
masses of $O(1)$TeV.


title: SU(3) Flux Tubes in a Model of the stochastic Vacuum

abstract:
  We calculate the squared gluon field strengths of a heavy q-$\rm
\bar{q}$-pair in the model of the stochastic vacuum. We observe that with
increasing separation a chromoelectric flux tube is built. The properties of
the emerging flux tube are investigated.


title: The Electromagnetic Catalysis of the Neutrino Radiative Decay

abstract:
  The radiative decay of the massive neutrino $\nu_i \rightarrow \nu_j \gamma (
m_i > m_j )$ in the external electromagnetic field is analyzed in detail in the
framework of the standard model with lepton mixing. It is shown, that a sort of
a catalysis of the neutrino radiative decay takes place. The effect of
catalysis is significant in the strong electromagnetic fields ($F \gg B_e =
m^2_e / e \simeq 4.41 \cdot 10^{13}$ G) ; it is more pronounced in the case of
the decay of the ultrarelativistic neutrino $(E_{\nu} \gg m_{\nu})$, even in a
relatively weak electromagnetic field ($F \ll m^2_e/e$).


title:
Probing Factorization in Color-Suppressed $B \rightarrow \psi(2S) +
  K(K^*)$ Decay

abstract:
  In order to probe the factorization hypothesis in color-suppressed $B
\rightarrow \psi (2S) + K (K^*)$ decays we have studied three ratios: $ R
\equiv B (B \rightarrow \psi K) / B (B \rightarrow \psi(2S) K)$, $ R' \equiv B
(B \rightarrow \psi K^*) / B (B \rightarrow \psi(2S) K^*)$ and $ P_L^\prime
\equiv \Gamma_L (B \rightarrow \psi(2S) K^*)/\Gamma (B \rightarrow \psi(2S)
K^*)$ in several scenarios for the $ q^2$-dependence of the form factors
involved. We find that measurements of R and $R' $, which exist, do not yield
scenario-independent tests of factorization. However, the predicted range of $
P_L^\prime$ in all scenarios lies in a narrow range, $ 0.50 {\
\lower-1.2pt\vbox{\hbox{\rlap{$<$}\lower5pt\vbox{\hbox{$\sim$}}}}\ } P_L^\prime
\leq 0.67$, and could test factorization.


title: Soft Jets and Top Mass Measurement at the Tevatron

abstract:
  Extra soft jets in top events in $p \bar p$ collisions may arise not only
from gluons radiated off initial state partons or final state $b$ quarks, but
may also be radiated from the $t$ quarks themselves. We discuss predictions for
distributions of soft gluons in $t \bar t$ production at the Tevatron and the
implications for attempts to measure the top mass by reconstructing the
invariant mass of its decay products.


title: Neutron Electric Dipole Momento in Two-Higgs-Doublet Model

abstract:
  The effect of the "chromo-electric" dipole moment on the electric dipole
moment(EDM) of the neutron is studied in the two-Higgs-doublet model.
  The Weinberg's operator $O_{3g}=GG\t G$ and the operator $O_{qg}=\bar
q\sigma\t Gq$ are both investigated in the cases of $\tan\b\gg 1$, $\tan\b\ll
1$ and $\tan\b\simeq 1$.
  The neutron EDM is considerably reduced due to the destructive contribution
with two light Higgs scalars exchanges.


title:
On the Solution to the Polonyi Problem with $O$(10~TeV) Gravitino Mass
  in Supergravity

abstract:
  We study the solution to the Polonyi problem where the Polonyi field weighs
as $O(10{\rm TeV})$ and decays just before the primordial nucleosynthesis. It
is shown that in spite of a large entropy production by the Polonyi field
decay, one can naturally explain the present value of the baryon-to-entropy
ratio, $n_B/s \sim (10^{-10}-10^{-11})$ if the Affleck-Dine mechanism for
baryogenesis works. It is pointed out, however, that there is another
cosmological problem related to the abundance of the lightest superparticles
produced by the Polonyi decay.


title: The Bjorken System of Equations and Nucleon Spin Structure-Function Data

abstract:
  The status of the Bjorken sum rule is examined in the light of recent data on
the spin structure functions of the deuteron and proton obtained by the SMC
group, the neutron by the E142 group and the proton by the E143 group.
Combining the new data with that already obtained for the proton by the EMC
group and SLAC/YALE collaborations, we show that the Bjorken system of
equations is violated at the 2-3 sigma level. We also discuss in detail the
role of possible higher-twist contributions and higher-order PQCD corrections.


title: Neutrino Masses from Gauge Symmetries

abstract:
  A very simple extension of the standard model to include an Abelian family
symmetry is able to describe the hierarchy of quark and lepton masses and their
mixing angles together with the unification of gauge couplings. We consider the
implications of this model for neutrino masses and mixing angles and show that
they are determined up to a discrete ambiguity corresponding to the
representation content of the Higgs sector responsible for the Majorana mass
matrix.


title:
Higher Twist, Polarised Structure Functions and the Bjorken System of
  Equations

abstract:
  We discuss the present situation with regard to polarised nucleon structure
function measurements. In particular we examine the status of the Bjorken sum
rule in the light of the recent data on the spin structure functions of (i) the
deuteron obtained by the SMC group at CERN and (ii) the neutron by the E142
group at SLAC. In order to fully exploit all the available data it is necessary
to study the complete Bjorken system of equations, which may be done in any of
several equivalent ways. Combining the new data with that already obtained for
the proton by the EMC group and earlier SLAC/YALE collaborations, together with
bounds obtained on the strange quark polarisation, we show that the Bjorken
system of equations is violated at about the 2 sigma level. We also show, using
unpolarised data, that arguments based on possible higher-twist contributions
are unable to account for this discrepancy. In conclusion, a simple explanation
in terms of a non-perturbative renormalisation of the relevant Wilson
coefficients is presented.


title: Mass singularities in light quark correlators: the strange quark case

abstract:
  The correlators of light-quark currents contain mass-singularities of the
form log(m^2/Q^2). It has been known for quite some time that these mass-
logarithms can be absorbed into the vacuum expectation values of other
operators of appropriate dimension, provided that schemes without normal-
ordering are used. We discuss in detail this procedure for the case of the mass
logarithms m^4 log(m^2/Q^2), including also the mixing with the other
dimension-4 operators to two-loop order. As an application we present an
improved QCD sum rule determination of the strange-quark mass. We obtain m_s(1
GeV)=171 \pm 15 MeV.


title:
Model Independent Determination of the Solar Neutrino Spectrum with and
  without MSW

abstract:
  Besides the opportunity for discovering new neutrino physics, solar neutrino
measurements provide a sensitive probe of the solar interior, and thus a
rigorous test of solar model predictions. We present model independent
determinations of the neutrino spectrum by using relevant flux components as
free parameters subject only to the luminosity constraint. (1) Without the
Mikheyev-Smirnov-Wolfenstein (MSW) effect, the best fit for the combined data
is poor. Furthermore, the data indicate a severe suppression of the $^7$Be flux
relative to the $^8$B, contradicting both standard and nonstandard solar models
in general; the $pp$ flux takes its maximum value allowed by the luminosity
constraint. This pathology consistently appears even if we ignore any one of
the three data. (2) In the presence of the two-flavor MSW effect, the current
constraint on the initial $^8$B flux is weak, but consistent with the SSM and
sufficient to exclude nonstandard models with small $^8$B fluxes. No meaningful
constraint is obtained for the other fluxes. In the future, even allowing MSW,
the $^8$B and $^7$Be fluxes can be determined at the $\pm$(15 -- 20)\% level,
making competing solar models distinguishable. We emphasize that the neutral
current sensitivity for $^7$Be neutrinos in BOREXINO, HELLAZ, and HERON is
essential for determining the initial fluxes. The constraints on the MSW
parameters in the model independent analysis are also discussed.


title: The Rise in F_2^p at HERA

abstract:
  We show that the rise in $F_2^p$ at small $x$ and large $Q^2$ seen at HERA is
indeed the non-Regge double asymptotic scaling behaviour expected from the
perturbative emission of strongly ordered hard gluons. An alternative
explanation, in which there is no strong ordering, and a new hard Reggeon is
generated, is also tried but found wanting: its theoretical short-comings are
betrayed by its failure to properly account for the HERA data.


title: Calculating F_2^p at small x and large Q^2

abstract:
  We show that the double asymptotic scaling of the HERA structure function
data is consistent with pre-HERA data at larger $x$, soft pomeron behaviour at
small $x$ and a sensible starting scale $Q_0$. We can thus actually calculate
$F_2^p$ at small $x$ and large $Q^2$ by evolving up perturbatively at two
loops, without any fitting.