title:
Jet rates in deep inelastic scattering: wherefrom comes the sensitivity
  to \alpha_s?

abstract:
  For theoretically consistent determination of $\alpha_s$ from jet rates in
deep inelastic scattering the dependence on $\alpha_s$ of parton distribution
functions is in principle as important as that of hard scattering
cross-sections. For the kinematical region accessible at HERA we investigate in
detail numerical importance of these two sources of the $\alpha_s$ dependence
of jet rates.


title: Tests and Implications of Increasing Evidence for Superpartners

abstract:
  Although no individual piece of experimental evidence for supersymmetry is
compelling so far, several are about as good as they can be with present
errors. Most important, all pieces of evidence imply the same values for common
parameters --- a necessary condition, and one unlikely to hold if the hints
from data are misleading. The parameters are sparticle or soft-breaking masses
and $ tan \beta.$ For the parameter ranges reported here, there are so far no
signals that should have occurred but did not. Given those parameters a number
of predictions can test whether the evidence is real. It turns out that the
predictions are mostly different from the conventional supersymmetry ones, and
might have been difficult to recognize as signals of superpartners. They are
testable at LEP2, where neutralinos and charginos will appear mainly as
$\gamma\gamma +$ large $\slashchar{E}$ events, $\gamma +$ very large
$\slashchar{E}$ events, and very soft lepton pairs of same or mixed flavor. The
results demonstrate that we understand a lot about how to extract an effective
SUSY Lagrangian from limited data, and that we can reasonably hope to learn
about the theory near the Planck scale from the data at the electroweak scale.


title:
New Mechanism of Flavor Symmetry Breaking from Supersymmetric Strong
  Dynamics

abstract:
  We present a class of supersymmetric models in which flavor symmetries are
broken dynamically, by a set of composite flavon fields. The strong dynamics
that is responsible for confinement in the flavor sector also drives flavor
symmetry breaking vacuum expectation values, as a consequence of a
quantum-deformed moduli space. Yukawa couplings result as a power series in the
ratio of the confinement to Planck scale, and the fermion mass hierarchy
depends on the differing number of preons in different flavor symmetry-breaking
operators. We present viable non-Abelian and Abelian flavor models that
incorporate this mechanism.


title: Next to Leading Order Three Jet Production at Hadron Colliders

abstract:
  I present results from a next-to-leading order event generator of purely
gluonic jet production. This calculation is the first step in the construction
of a full next-to-leading order calculation of three jet production at hadron
colliders. Several jet algorithms commonly used in experiments are implemented
and their numerical stability is investigated. A numerical instability is found
in the iterative cone algorithm which makes it inappropriate for use in fixed
order calculations beyond leading order.


title: Sudakov Effects in Higgs Production at the LHC

abstract:
  We discuss the resummation of Sudakov effects in a cross section from the
viewpoint of its underlying factorization near the edge of phase space. We
perform the resummation of Sudakov threshold logarithms in Higgs (Standard
Model and Minimal Supersymmetric SM) production at the LHC, using an evolution
equation in the Higgs mass that is derived from this factorization. We extend
the class of universal large terms that is resummed to include additional
universal contributions, which, when included, help to reproduce the exact
result to within a few percent for the full allowed range of Higgs boson masses
in the SM and MSSM. Using the analytic resummed formula as a generating
functional for approximate perturbation theory, we show results for
next-to-next-to-leading order corrections in Higgs production, and find they
are potentially sizable.


title: An Inflaton Candidate in Gauge Mediated Supersymmetry Breaking

abstract:
  Inflation, as currently understood, requires the presence of fields with very
flat potentials. Supersymmetric models in which supersymmetry breaking is
communicated by supergravity naturally yield such fields, but the scales are
typically not suitable for obtaining both sufficient inflation and a suitable
fluctuation spectrum. In the context of recent ideas about gauge mediation,
there are new candidates for the inflaton. We present a simple model for
slow-rollover inflation where the vacuum energy driving inflation is related to
the same F-term responsible for the spectrum of supersymmetric particles in
gauge mediated supersymmetry breaking models. The inflaton is identified with
field responsible for the generation of the $\mu$-term\. This opens the
possibility of getting some knowledge about the low-energy supersymmetric
theory from measurements of the cosmic microwave background radiation.
Gravitinos do not pose a cosmological problem, while the moduli problem is
ameliorated.


title: On the probability distribution of the experimental results

abstract:
  The analysis of Tables of particle properties shows that the probability
distribution of the results of physical measurements is far from the
conventional Gaussian $\rho(\xi)=exp(-\xi^2/2) $, but is more likely to follow
the simple exponential law $\rho(\xi)=exp(-\xi)$ ($\xi$ is the deviation of the
measured from the true value in units of the presented standard error). A gap
between the expected and actual probabilities grows with $\xi$ very rapidly,
amounting to $ 10^7 $ at $\xi\approx 6 $, and is significant even at $\xi=2 $.
A more detailed study reveals the two-component structure of the distribution:
the $exp(-\xi)$ law is closely fulfilled up to $\xi=3$, but then, at $\xi$
larger than that, the decrease is retarded drastically. This behaviour can be
associated with the existence of two various types of systematic errors, the
detected and undetected ones. Within some model, both types of errors are seen
to affect the form of the distribution, one at moderate $\xi$ and the other at
large $\xi$. The first type (detected) errors are shown in some natural-looking
assumptions to yield the distribution not quite equal but close to the simple
exponential.


title:
Single-top production in the $tW^\pm$ channel and Higgs signals via
  $H\to W^+W^-$ at the Large Hadron Collider

abstract:
  In a recent study by Dittmar and Dreiner it was shown that with appropriate
selection cuts the signature of events containing two charged leptons and
missing energy represents the best chance of detecting the Standard Model Higgs
scalar in the mass range between 155 and 180 GeV, the primary decay of the
Higgs being into pairs of charged gauge bosons. The largest background to this
channel is due to irreducible $W^+W^-X$ production. In the present paper we
calculate the contribution of events of the type $bg\to tW^\pm\to b W^+W^-\to b
\ell^{+}\ell^{'-}\nu_\ell\bar\nu_{\ell'}$, which have not been considered yet
within the new selection strategy. We show that the yield of this background is
rather large, at the level of that produced by $W^+W^-$, $t\bar t$ or $tb
W^\pm$ events and thus needs to be incorporated in future experimental
analyses. However, we find that its inclusion will not spoil the possibilities
of Higgs detection in the above mentioned channel at the Large Hadron Collider.


title:
The processes $e^+e^-\to b\bar bW^\pm H^\mp$ and $e^+e^-\to b\bar
  bH^+H^-$ at the Next Linear Collider in the Minimal Supersymmetric Standard
  Model

abstract:
  The complete matrix elements for $e^+e^-\to b\bar bW^\pm H^\mp$ and
$e^+e^-\to b\bar bH^+H^-$ are computed at tree-level within the Minimal
Supersymmetric Standard Model. Rates of interest to phenomenological analyses
at the Next Linear Collider are given. In particular, we analyse: (i) $t\bar t$
pair production followed by the top decays into $b\bar bW^\pm H^\mp$ and $b\bar
b H^+H^-$ final states; (ii) $H^+H^-$ signals in which $H^\pm\to h W^\pm \to
b\bar b W^\pm$ and $H^\pm\to tb\to b\bar b W^\pm$. Top and Higgs finite width
effects are included as well as all those due to the irreducible backgrounds.


title: Violations of Local Duality in the Heavy Quark Sector

abstract:
  We examine the origin of possible failures of the quark-hadron local duality.
In particular, we consider a correlator of two currents comprising heavy quark
operators, and compare the evaluation by the Operator Product Expansion with
the result obtained inserting an infinite set of hadronic states, in the N_c to
infinity limit. Whereas the smeared spectral functions agree with each other,
their local behaviour is different. The difference manifests itself in the form
of a term O(Lambda/epsilon) (epsilon being the residual energy) that is not
present in the expansion in powers of Lambda/epsilon predicted by the OPE.


title: Intermediate Scales, Mu Parameter, and Fermion Masses from String Models

abstract:
  We address intermediate scales within a class of string models. The
intermediate scales occur due to the SM singlets S_i acquiring non-zero VEVs
due to radiative breaking; the mass-square (m_i)^2 of S_i is driven negative at
mu_{RAD} due to order(1) Yukawa couplings of S_i to exotic particles
(calculable in a class of string models). The actual VEV of S_i depends on the
relative magnitude of the non-renormalizable terms of the type (S_i)^{K+3}/M^K
in the superpotential. We mainly consider the case in which the S_i are charged
under an additional non-anomalous U(1) gauge symmetry and the VEVs occur along
F- and D-flat directions. We explore various scenarios in detail, depending on
the type of Yukawa couplings to the exotic particles and on the initial
boundary values of the soft SUSY breaking parameters. We then address the
implications of these scenarios for the mu parameter and the fermionic masses
of the standard model.


title:
A Study of the Day - Night Effect for the Super-Kamiokande Detector: II.
  Electron Spectrum Deformations and Day - Night Asymmetries

abstract:
  Using the results of a high precision calculation of the solar neutrino
survival probability for Earth crossing neutrinos in the case of MSW $\nu_e \to
\nu_{\mu(\tau)}$ transition solution of the solar neutrino problem, performed
in an earlier study, we derive predictions for the one-year averaged day-night
(D-N) asymmetry in the deformations of the $e^-$ - spectrum to be measured with
the Super - Kamiokande detector, and for the D-N asymmetry in the energy-
integrated one year signal in this detector. The asymmetries are calculated for
solar $\nu_e$ crossing the Earth mantle only, the core and the (mantle + core)
for a large representative set of values of the MSW transition parameters
$\Delta m^2$ and $\sin^2 2\theta_v$ from the ``conservative'' MSW solution
region obtained by taking into account possible uncertainties in the values of
the $^8$B and $^7$Be neutrino fluxes. The effect of the uncertainties in the
value of the bulk matter density and in the chemical composition of the core,
on the D-N asymmetry predictions is discussed. It is shown, in particular, that
for $\sin^2 2\theta_v \leq 0.013$ the one year average D-N asymmetry for
neutrinos crossing the Earth core can be larger than the asymmetry for (only
mantle crossing + core crossing) neutrinos by a factor of up to six. Iso -
(D-N) asymmetry contours in the $\Delta m^2 - \sin^2 2\theta_v$ plane for the
Super - Kamiokande detector are derived in the region $\sin^2 2\theta_v \gsim
10^{-4}$ for only mantle crossing, core crossing and (only mantle crossing +
core crossing) neutrinos. Our results indicate that the Super - Kamiokande
experiment might be able to test the $\sin^2 2\theta_v \le 0.01$ region of the
MSW solution of the solar neutrino problem by performing selective D-N
asymmetry measurements.


title: Light-cone Variables, Rapidity and All That

abstract:
  I give a pedagogical summary of the methods of light-cone variables, rapidity
and pseudo-rapidity. Then I show how these methods are useful in analyzing
diffractive high-energy collisions.


title: Lepton Flavour Violation in a Left-Right Symmetric Model

abstract:
  We consider in this paper a Left-Right symmetric gauge model in which a
global lepton-number-like symmetry is introduced and broken spontaneously at a
scale that could be as low as 10^4 GeV or so. The corresponding physical
Nambu-Goldstone boson, which we call majoron and denote J, can have tree-level
flavour-violating couplings to the charged fermions, leading to sizeable
majoron-emitting lepton-flavour-violating weak decays. We consider explicitly a
leptonic variant of the model and show that the branching ratios for \mu ->
e+J, \tau -> e + J and \tau -> \mu + J decays can be large enough to fall
within the sensitivities of future \mu and \tau factories. On the other hand
the left-right gauge symmetry breaking scale may be as low as few TeV.


title:
e^+ (Anti)Quark Scattering in the Presence of the Anomalous HERA
  Positron-Jet Event Phenomenon

abstract:
  We discuss the leptoquark interpretation of the anomalous HERA positron-jet
events in the context of the YFS exponentiated Monte Carlo event generator
treatment of the attendant multiple photon radiative effects for both the
would-be signal and the SM background, wherein finite-$p_T$ photon effects are
properly taken into account and wherein infrared singularities are cancelled to
all orders in $\alpha$. We show that H1 and ZEUS data are consistent with such
an interpretation for a leptoquark coupling $\lesssim 0.3g_W$, mass $\sim 200$
GeV, and width $\lesssim 2$GeV. Possible future tests are proposed.


title: Final-State Interactions in Heavy Quark Decays

abstract:
  We study the role played by the final-state interactions (fsi) in heavy quark
decays using Pomeron and Regge exchanges to describe high energy scattering. At
center of mass energy $\sqrt{s}\sim 5GeV $, Pomeron dominance does not apply.
We study the behavior of the decay amplitudes as $\sqrt{s} $ is varied close to
the B mass. We also investigate the behavior of the decay amplitude as
$\sqrt{s}\to \infty $. Our conclusion is that the decay amplitudes approach a
real value asymptotically.


title: Flavor Changing Neutral Currents in Charm Sector

abstract:
  I would like to discuss $D^0-\bar{D}^0$ the mixing and rare D decays as
manifestations of Flavor Changing Neutral Currents (FCNC) in the charm sector.
I will first review the expectations in the Standard Model (SM) and then
summarize some typical expectations in new physics scenarios. I would like to
argue that the charm case offers a large window of opportunity and it may be
possible to learn something about the origin of the fermion mass matrix.


title: Single-Top-Quark Production via W-Gluon Fusion at Next-to-Leading Order

abstract:
  Single-top-quark production via W-gluon fusion at hadron colliders provides
an opportunity to directly probe the charged-current interaction of the top
quark. We calculate the next-to-leading-order corrections to this process at
the Fermilab Tevatron, the CERN Large Hadron Collider, and DESY HERA. Using a
b-quark distribution function to sum collinear logarithms, we show that there
are two independent corrections, of order 1/[ln(m_t^2/m_b^2)] and alpha_s. This
observation is generic to processes involving a perturbatively derived
heavy-quark distribution function at an energy scale large compared with the
heavy-quark mass.


title: Modified parton distributions and the HERA high-Q^2 anomaly

abstract:
  A recent proposal seeks to explain the anomaly in the HERA high-Q^2 neutral
current e^+p data by modifying the parton distribution functions at
moderate-to-high-x and large Q^2. We investigate the consequences of this
proposal for the HERA high-Q^2 data itself, in the neutral current e^-p channel
and especially in the charged current e^\pm p channels. We find that there are
striking signatures in the charged current which already serve to rule out many
possibilities, including the (symmetric) intrinsic charm hypothesis. For those
not ruled out, interesting signals are predicted in e^-p scattering.


title:
Effects of the Electroweak Symmetry Breaking Sector in Rare B and K
  Decays

abstract:
  The effects of the electroweak symmetry breaking sector in rare $B$ and $K$
decays are considered in the presence of new strong dynamics at a large energy
scale. In the context of the low energy effective lagrangian of the symmetry
breaking sector, we focus on the contributions that are not constrained by
bounds on oblique corrections or anomalous triple gauge boson vertices. We find
that these have very little effect in $b\to s\gamma$, but potentially large
contributions appear in $b\to s\ell^+\ell^-$ and $b\to s\nu\bar\nu$ as well as
in $b\to s g$ processes. Deviations from the standard model in rare $K$ decays
such as $K^+\to\pi^+\nu\bar\nu$ and $K_L\to\pi^0\nu\bar\nu$ are shown to be
correlated with the ones in the $B$ modes. The distinct resulting pattern of
deviations from the standard model in rare decays is a characteristic feature
of a strongly interacting electroweak symmetry breaking sector.


title:
K-matrix analysis of the K-pi S-wave in the mass region 900-2100 Mev and
  nonet classification of scalar qqbar-states

abstract:
  A K-matrix re-analysis of the K-pi S-wave is performed in the mass region
900-2100 MeV, and solutions which describe the data well are found. The
solution with two resonances in the (IJ^P=1/2 0^+)-wave has poles at (1415 pm
25)- i(165 pm 25) MeV and (1820 pm 40) -i(125 pm 50) MeV, close to the previous
result of D. Aston et al., Nucl.Phys., B296 (1988) 493. The corresponding bare
states, which are the subjects of a qqbar classification, are:
K_0^{bare}(1220^{+50}_{-60}) and K_0^{bare}(1885^{+50}_{-80}). Within the
restored bare states, a construction of the 1^3P_0 qqbar and 2^3P_0 qqbar
nonets is completed. The three resonance solutions are analysed as well, the
corresponding bare states are found, and the qqbar-nonet classification is
suggested. In all variants of our qqbar-classification, the resonances a_0(980)
and f_0(980) (or their bare counterparts) are non-exotic, and an extra
scalar/isoscalar state exists in the mass region 1300-1700 MeV, being a good
candidate for the lightest scalar glueball.


title:
New Possibility of Solving the Problem of Lifetime Ratio $\tau
  (\Lambda_b) / \tau (B_d)$

abstract:
  We discuss the problem of the large discrepancy between the observed lifetime
ratio of $\Lambda_b$ to $B_d$ and the theoretical prediction obtained by the
heavy quark effective theory. A new possibility of solving this problem is
proposed from the viewpoint of operator product expansion and the lifetime
ratio of $\Omega_b$ to $B_d$ is predicted.


title: Squark and Gluino Production at Hadron Colliders

abstract:
  The determination of the full SUSY QCD corrections to the production of
squarks and gluinos at hadron colliders is reviewed. The inclusion of the NLO
corrections stabilizes the theoretical predictions of the various production
cross sections significantly and leads to sizeable enhancements of the most
relevant cross sections. We discuss the phenomenological consequences of the
results on present and future experimental analyses. Finally we investigate the
impact of the corrections on the transverse momentum and rapidity
distributions.


title: CP Violation in $B_s$ Decays

abstract:
  CP-violating effects in non-leptonic $B_s$-meson decays are reviewed. Special
emphasis is given to implications arising from the width difference
$\Delta\Gamma_s$ between the $B_s$ mass eigenstates. If $\Delta\Gamma_s$ is
found to be sizable, certain untagged $B_s$-meson decays may allow interesting
probes of CP violation, extractions of the CKM angle $\gamma$ and the
Wolfenstein parameter $\eta$, and may indicate physics beyond the Standard
Model.


title:
$\mu \to e \gamma$ in supersymmetric multi U(1) models with an abelian
  gaugino mixing

abstract:
  A lepton flavor violating process $\mu\to e\gamma$ is investigated in the
supersymmetric extra U(1) models, which often appear as the low energy
effective models of superstring and can potentially solve the $\mu$-problem.
The branching ratio of this process is calculated. It is numerically estimated
and compared with that of the MSSM. In this study we take account of an abelian
gaugino kinetic term mixing and discuss its influence on this process. The
possibility to find the extra gauge structure through this process is
discussed.


title: Signals of spontaneous R parity breaking at LEP and at a linear collider

abstract:
  We study the production of neutralinos and charginos at LEP and at a linear
collider in the case of spontaneously broken R-parity. We first investigate the
constraints on the single neutralino and chargino production from the LEP 1
experiments, and then we consider the production at LEP 2 and at a linear
collider. We concentrate on the supersymmetric $SU(2)_L \times SU(2)_R \times
U(1)_{B-L}$ model, where the spontaneous R-parity breaking is inevitable and is
associated with the breaking of the LR-symmetry.


title: Quark States near a Threshold and the Unstable H-dibaryon

abstract:
  We consider the interplay of a quark state and a hadronic threshold in the
framework of the P-matrix formalism, which is reviewed and extended for use
together with conventional methods of computing quark-gluon dynamics. We
provide a quantitative dynamical interpretation of the reduced R or K matrices
and their poles that suggests a natural classification of threshold phenomena.
At a threshold with a quark state close to it up to three S-matrix poles can be
found. The scattering amplitudes for the corresponding cases are discussed. Our
analysis is applied to make an outlook for experimental observation of the
doubly strange H-dibaryon if it is not stable to strong decays.


title: A Three-Dimensional Code for Muon Propagation through the Rock: MUSIC

abstract:
  We present a new three-dimensional Monte-Carlo code MUSIC (MUon SImulation
Code) for muon propagation through the rock. All processes of muon interaction
with matter with high energy loss (including the knock-on electron production)
are treated as stochastic processes. The angular deviation and lateral
displacement of muons due to multiple scattering, as well as bremsstrahlung,
pair production and inelastic scattering are taken into account. The code has
been applied to obtain the energy distribution and angular and lateral
deviations of single muons at different depths underground. The muon
multiplicity distributions obtained with MUSIC and CORSIKA (Extensive Air
Shower simulation code) are also presented. We discuss the systematic
uncertainties of the results due to different muon bremsstrahlung
cross-sections.


title: KN Scattering and the Nucleon Strangeness Radius

abstract:
  The leading non-zero electric moment of the nucleon strange-quark vector
current is the mean square strangeness radius, $<r_s^2>$. We evaluate the
lightest OZI-allowed contribution to $<r_s^2>$, arising from the kaon cloud,
using dispersion relations. Drawing upon unitarity constraints as well as
$K^{+}N$ scattering and $e^+e^-\to K\bar{K}$ cross section data, we find the
structure of this contribution differs significantly from that suggested by a
variety of QCD-inspired model calculations. In particular, we find evidence for
a strong $\phi$-meson resonance which may enhance the scale of kaon cloud
contribution to an observable level.


title: b b-bar Production on the Z Resonance and Implications for LEP2

abstract:
  In terms of an effective lagrangian, we examine the effect of new physics
associated with third-generation fermions on b b-bar production at the Z
resonance and study its implications for LEP2. We obtain the constraints on
such operators with derivative couplings at LEP1 and the SLC, and determine the
prospects for detecting their presence at LEP2. We find that despite the small
observed deviations from the standard model on the Z resonance, much larger
deviations from standard model predictions are possible at LEP2, and the
corresponding couplings can be determined rather precisely.


title: Flavor from Strongly Coupled Supersymmetry

abstract:
  Strongly coupled supersymmetric theories can give rise to composite quarks
and leptons at low energy. We show that the internal structure of these
particles can explain the origin of three generations and provide a qualitative
understanding of mass ratios and mixing angles between the different flavors of
fermions, all within a renormalizable theory. The main point of the paper is to
show how fermion masses and mixing angles can result from a ``dual''
Frogatt-Nielsen mechanism: fields neutral under $SU(3) \times SU(2) \times
U(1)$ which carry flavor quantum numbers are confined within quarks and
leptons, and from their perturbative interactions arises the observed flavor
structure.


title:
Effect on the electron EDM due to abelian gauginos in SUSY extra U(1)
  models

abstract:
  The electric dipole moment of an electron (EDME) is investigated in the
supersymmetric extra U(1) models. Neutralino sector is generally extended in
these models and then the neutralino contribution will be important for the
analysis of the EDME. Kinetic term mixings of abelian gauginos are taken into
account in our analysis. Numerical results for the extra U(1) models show that
the EDME can be affected by the extra U(1) in a certain range of soft
supersymmetry breaking parameters even if the extra U(1) gauge boson is heavy.
The EDME may be a clue to find an extended gauge structure in the
supersymmetric models.


title: Light-Cone Wavefunctions at Small $x$

abstract:
  There exist an infinite number of exact small momentum fraction-$x$ boundary
conditions on light-cone wavefunctions of bound states in gauge theory. They
are necessary for finite expectation values of the invariant mass operator and
relate components of the wavefunction from different Fock sectors. We
illustrate their consequences by analyzing the small-$x$ quark Regge behavior
of a heavy large-$N$ meson, finding power-law rise of unpolarized
distributions. The polarized distribution changes sign and then vanishes with
minus the unpolarized Regge intercept.


title: Implications of a charged-current anomaly at HERA

abstract:
  We demonstrate that in the presence of mixing between different scalar
leptoquark multiplets it is possible to simultaneously account for the HERA
high-$Q^2$ neutral current anomaly, and produce a charged current anomaly of
comparable magnitude. The reduced branching ratio to electrons and jets of the
lightest leptoquark state results in a significant weakening of the CDF/D0
limits on scalar leptoquarks; masses consistent with the HERA neutral current
excess are comfortably within the allowed range. We show that the possibilities
for such a successful mixed leptoquark scenario are quite limited, and we
investigate some aspects of their phenomenology.


title: Next-to-Leading Order Evolution of Polarized Fragmentation Functions

abstract:
  We present a brief description of the determination of the two-loop
spin-dependent time-like splitting functions relevant for the NLO evolution of
polarized fragmentation functions. Our calculation based on the analytic
continuation of the corresponding space-like results obtained within the
light-cone gauge method proposed by Curci, Furmanski, and Petronzio. As an
application we present an analysis of polarized Lambda production in e+e- and
ep collisions.


title: Pursuing the Strange Stop Interpretation of the HERA Large Q^2 data

abstract:
  We explore the possible interpretation of the large-$Q^2$ anomaly reported by
the H1 and ZEUS collaborations in terms of stop squark production off a strange
quark in the proton via an R-violating interaction. This "strange stop"
interpretation is constrained by LEP measurements of the $Z \to e^+ e^-$ decay
rate in addition to constraints from the electroweak $\rho$ parameter and CDF
and D0 searches for first-generation leptoquarks. We investigate the interplay
between these constraints, taking full account of stop mixing effects. We find
that if $m_{\tilde t} \le 200$ GeV only relatively small domains of the
chargino and neutralino parameters are consistent with these constraints, and
explore the extent to which this scenario may be probed further by searches for
contact interactions at LEP~2 and experiments with $e^-$ and polarized beams at
HERA.


title:
Exact Results for Soft Supersymmetry Breaking Parameters in
  Supersymmetric Gauge Theories

abstract:
  We obtain exact relations (valid to all orders in the coupling constant) for
the running gaugino mass in supersymmetric gauge theories, treating the soft
supersymmetry breaking effects in the linear approximation. If a supersymmetry
breaking squark (selectron) mass term is introduced, our relation connects the
renormalization group equation for this term with that for the gaugino mass.
Exact relations for the threshold effects in the gaugino masses are derived.
The key ingredients of our analysis is the use of the Wilsonean action and
holomorphy of this action with respect to relevant parameters.


title: Spontaneous CP Violation in Models with Anomalous U(1)

abstract:
  We examine a class of Froggatt-Nielsen models with an anomalous U(1) as the
flavor dependent symmetry. Anomaly cancellation and unbroken supersymmetry
impose constraints on the U(1)_X charges of the fermions and the vacuum
expectation values of the symmetry-breaking scalars. We show by example that it
is possible to find models that reproduce the observed masses and mixings of
the standard model fermions, and exhibit a realistic amount of CP violation.


title: Multiquark states and QCD sum rules

abstract:
  There have been arguments about hadronic molecules, which are weakly-bound
states of two or more hadrons. We investigate the possibility of some
candidates (f0 (980), a0 (980), f0 (1500), f0 (1710), etc.) using QCD sum rule
approach and compare our results with multiquark states in the MIT bag model.
We find that f0 (1500), f0 (1710) can be good candidates for vector-vector
molecule-type multiquark states.


title: New Precision Electroweak Tests in Supergravity Models

abstract:
  We update the analysis of the precision electroweak tests in terms of 4
epsilon parameters, $\epsilon_{1,2,3,b}$, to obtain more accurate experimental
values of them by taking into account the new LEP data released at the 28th
ICHEP (1996, Poland). We also compute $\epsilon_1$ and $\epsilon_b$ in the
context of the no-scale $SU(5)\times U(1)$ supergravity model to obtain the
updated constraints by imposing the correlated constraints in terms of the
experimental ellipses in the $\epsilon_1-\epsilon_b$ plane and also by imposing
the new bound on the lightest chargino mass, $m_{\chi^\pm_1}\gtrsim 79$ $ GeV$.
Upon imposing these new experimental results, we find that the situations in
the no-scale model are much more favorable than those in the standard model,
and if $m_t\gtrsim 170$ $ GeV$, then the allowed regions at the 95% C.~L. in
the no-scale model are $\tan\beta\gtrsim 4$ and $m_{\chi^\pm_1}\lesssim 120
(82)$ $ GeV$ for $\mu>0 (\mu<0)$, which are in fact much more stringent than in
our previous analysis. Therefore, assuming that $m_t\gtrsim 170$ $ GeV$, if the
lightest chargino mass bound were to be pushed up only by a few GeV, the sign
on the Higgs mixing term $\mu$ in the no-scale model could well be determined
from the $\epsilon_1-\epsilon_b$ constraint to be positive at the 95% C.~L. At
any rate, better accuracy in the measured $m_t$ from the Tevatron in the near
future combined with the LEP data is most likely to provide a decisive test of
the no-scale $SU(5)\times U(1)$ supergravity model.


title:
Algebraic approach to the spectral problem for the Schroedinger equation
  with power potentials

abstract:
  The method reducing the solution of the Schroedinger equation for several
types of power potentials to the solution of the eigenvalue problem for the
infinite system of algebraic equations is developed. The finite truncation of
this system provides high accuracy results for low-lying levels. The proposed
approach is appropriate both for analytic calculations and for numerical
computations. This method allows also to determine the spectrum of the
Schroedinger-like relativistic equations. The heavy quarkonium (charmonium and
bottomonium) mass spectra for the Cornell potential and the sum of the Coulomb
and oscillator potentials are calculated. The results are in good agreement
with experimental data.


title: Higher Order Bose-Einstein Correlations for Systems with Large Halo

abstract:
  A generalization of the core/halo model to the Bose-Einstein correlation
function of any number of particles is presented. In particular, a simple
prediction is obtained for the intercept parameter of the n-particle inclusive
Bose-Einstein correlation functions for arbitrary large values of n.


title: The gamma(*) pi(0) -> gamma form factor

abstract:
  The gamma(*) pi(0) -> gamma form factor is obtained within the Lagrangian
quark model with separable interaction known to provide a good description of
the pion observables at low energies. The pion-quarks vertex is chosen in a
Gaussian form. The form factor obtained is close to the available experimental
data and reaches smoothly the Brodsky-Lepage limit at Q2 = 10 GeV2.


title: Like Sign Top Pair Production at LHC

abstract:
  Having a mass comparable to the weak scale, the top quark may have a sizable
flavor changing couplings to Higgs bosons. We show that such couplings can be
probed at the LHC through the parton subprocess $c(\bar c)g \to t (\bar t)A^0$,
where the pseudoscalar $A^0$ subsequently decays into $t \bar c$ or ${\bar t}
c$, giving rise to the intriguing final state of like sign top quark pairs. We
also discuss major backgrounds to the above signal, in particular the QCD-Weak
process $q\bar q' \to W^+(W^-) t \bar t$. The issue of background reduction is
briefly discussed.


title:
Production Associated to Rare Events in High Energy Hadron-Hadron
  Collisions

abstract:
  At very high energy the same universal relation between the multiparticle or
the transverse energy distribution associated to a rare event $C$, $P_C$ and
the corresponding minimum bias distribution P, $P_C(\nu)\equiv \nu/<\nu>
P(\nu)$, $\nu\equiv n$ or $E_T$ works for nucleus-nucleus collisions as well as
for hadron-hadron collisions. This suggests that asymptotically, all hadronic
processes are similar.


title: Small x Physics and Why It's Interesting

abstract:
  I discuss small x physics and its implications at very high energies. At very
high energy the density of partons becomes so large that much of the physics
can be described using weak coupling methods in QCD. This may allow for a
solution to problems such as the asymptotic nature of deep inelastic scattering
at fixed momentum transfer, unitarization, and multiparticle production.


title:
Remark on the kinematics of the one-photon production in electron-proton
  scattering

abstract:
  I clarify the mistakes in the original version hep-ph/9705427 about the phase
space factor for the one-photon production in electron-proton scattering and
confirm that the earlier result given by Kroll, Sch\"urmann and Guichon is
right.


title: Two Remarks Concerning the Signs of the Light Quark Masses

abstract:
  Partial conservation of the nine axial currents $A^\beta_\mu$ for
$\beta=0,1,...,8$ applied to the vacuum expectation values of the equal-time
commutators of the nine axial charges $Q_A^\alpha(x_0)$ for $\alpha=0,1,...,8$
with the corresponding axial current divergences $\partial^\mu A_\mu^\beta $
implies that the non-vanishing current quark masses $m_u, m_d, m_s$ of the
light quarks $u, d, s$ have the same sign. Under the more realistic assumption
of partial conservation of only the eight axial currents of $SU(3)\otimes
SU(3)$, i.e. $\alpha=1,...,8$ and $\beta=1,...,8$ in the above, inequalities
for the quark masses follow. They are trivially fulfilled if the three light
quark masses have the same sign and imply, for non-vanishing quark masses $m_u,
m_d, m_s$, that at least two of these masses have the same sign as their sum
$m_u + m_d + m_s$. If one of the three quark masses vanishes, one of the other
two might also. If both do not, they have the same sign (the same, of course,
as their sum). Our assumptions include the standard vector SU(3) symmetry of
the vacuum.


title:
Exact $O(\alpha)$ Gauge Invariant YFS Exponentiated Monte Carlo for
  (Un)Stable for (Un)Stable $W^+W^-$ Production At and Beyond LEP2 Energies

abstract:
  We realize, by Monte Carlo event generator methods, the exact O}(\alpha)$ YFS
exponentiated calculation of $e^+e^- \to W^+ W^- (\to f_1\bar f'_1 + \bar f_2
f'_2)$ at and beyond LEP2 energies, where the left-handed parts of $f_i$ and
$f'_i$ are the respective upper and lower components of an $SU_{2L}$ doublet,
$i=1,2$. Our calculation is gauge invariant from the standpoint of its
radiative effects and the respective YFS Monte Carlo event generator YFSWW3,
wherein both Standard Model and anomalous triple gauge boson couplings are
allowed, generates $n(\gamma)$ radiation both from the initial state and from
the final $W^+ W^-$. Sample Monte Carlo data are illustrated.


title:
Gauge Invariant YFS Exponentiation of (Un)stable $Z$-Pair Production At
  and Beyond LEP2 Energies

abstract:
  We present the theoretical basis and sample Monte Carlo data for the YFS
exponentiated calculation of $e^+e^- \to Z Z \to f_1\bar f_1 + \bar f_2 f_2$ at
and beyond LEP2 energies, where the left-handed part of $f_i$ is a component of
an $SU_{2L}$ doublet, $i=1,2$. The calculation is performed for both SM
couplings and for anomalous $ZZV$ triple gauge boson couplings in the
conventions of Hagiwara et al.. Our formulas, which are gauge invariant, are
illustrated in a proto-typical YFS Monte Carlo event generator YFSZZ.


title:
Dokshitzer-Gribov-Lipatov-Altarelli-Parisi Evolution and the
  Renormalization Group Improved Yennie-Frautschi-Suura Theory in QCD

abstract:
  We show that the recently derived renormalization group improved
Yennie-Frautschi-Suura (YFS) exponentiation of soft $(k_o\to 0)$ gluons in QCD
is fully compatible with the usual Dokshitzer-Gribov-Lipatov-Altarelli-Parisi
(DGLAP) evolution of the structure functions of hadrons in the respective
hadron-hadron hard interactions. We show how to implement the YFS
exponentiation without double or over counting effects already implied by the
DGLAP equation. In this way, we arrive at a theory which allows for the
development of realistic, multiple gluon Monte Carlo event generators for hard
hadron-hadron scattering processes in which the DGLAP evolved structure
functions are correctly synthesized with the respective YFS exponentiated soft
gluon effects in a rigorous way.


title: Multi-Boson Correlations Using Wave-Packets

abstract:
  Brooding over bosons, wave packets and Bose - Einstein correlations, we
present a generic quantum mechanical system that contains arbitrary number of
bosons characterized by wave-packets and that can undergo a Bose-Einstein
condensation either by cooling, or increasing the number density of bosons, or
by increasing the overlap of the multi-boson wave-packet states, achieved by
changing the size of the single-particle wave-packets. We show that the
n-particle correlations may mimic coherent or chaotic behaviour for certain
limiting wave-packet sizes. Effects of complete n-particle symmetrization are
included. The resulting weights which fluctuate between 1 and n! are summed up
with the help of a formal analogy between the considered wave-packet system and
an already explored multi-boson plane-wave system. We solve the model
analytically in the highly condensed and in the rare gas limiting cases,
numerically in the intermediate cases. The relevance of the model to multi-pion
production in high energy heavy ion physics as well as to the Bose-Einstein
condensation of atomic vapours is discussed. As a by-product, a new class of
probability distribution functions is obtained, event-by-event fluctuations of
single-particle momentum distributions are predicted and the critical density
for the onset of pion-lasing in high energy heavy ion collisions is derived.

categories: hep-ph hep-th nucl-th physics.optics quant-ph


title: Analytic Solution of the Pion-Laser Model

abstract:
  Brooding over bosons, wave packets and Bose - Einstein correlations, we find
that a generalization of the pion-laser model for the case of overlapping
wave-packets is analytically solvable with complete n-particle symmetrization.
The effective radius parameter of the two-particle correlation function is
reduced for low values and enlargened for high values of the mean momentum in
the rare gas limiting case, as compared to the case when multi-particle
symmetrization effects are neglected.
  These results explicitly depend on the multiplicity, providing a theoretical
basis for event-by-event analysis of high energy heavy ion reactions.


title: The lepton anomaly in the presence of torsion

abstract:
  In the presence of a curved space-time with torsion, the divergence of the
leptonic current gets new contributions from the curvature and the torsion in
addition to those coming from the electroweak fields. However it is possible to
define a new lepton current which is gauge and local Lorentz invariant whose
divergence gets no contribution from the torsion. Therefore we argue that
torsion does not contribute to anomalous lepton number production


title: Atomic parity violation in cesium and implications for new physics

abstract:
  Recent high-precision measurements of atomic parity-nonconserving transitions
between the 6S and 7S states of cesium allow for a determination of the weak
nuclear charge with a precision of 1.3%, providing an improved test of the
standard model at low energy. Implications for new physics are examined in
terms of low energy effects on the weak charge, in particular contact
interactions and scalar leptoquark limits. Prospects for further improvements
are described.


title: Neutrino masses and mixing from neutrino oscillation experiments

abstract:
  What information about the neutrino mass spectrum and mixing matrix can be
inferred from the existing neutrino oscillation data? We discuss here the
answer to this question in the case of mixing of three and four neutrinos. We
present the constraints on the effective Majorana mass <m> that can be obtained
from the results of reactor neutrino oscillation experiments and from
atmospheric neutrino data. We discuss the bounds on the oscillation
probabilities in long-baseline neutrino oscillation experiments that follow
from the results of short-baseline experiments. Some remarks on a
model-independent approach to the solar neutrino problem are also made.


title:
Analysis of K\pi-scattering phase shift and existence of
  \kappa(900)-particle

abstract:
  Recently we have shown an evidence for existence of \sigma-particle in the
previous works; where the \pi\pi S-wave phase shift is reanalyzed, by
introducing a repulsive background suggested by the chiral symmetry, and by
applying a new method of Interfering Breit-Wigner Amplitudes. In this work we
also show, reanalyzing the K\pi S-wave phase shift from a similar standpoint,
an evidence for existence of \kappa(900), possibly to be a member of
\sigma-nonet.


title: Quark-antiquark resonances in the NJL model

abstract:
  The problem of the $\rho$ meson resonance solution in the extended NJL model
is studied. It has been shown previously that the solution for the $\rho$ meson
changes smoothly from a bound state to a "virtual state" when the vector
channel attraction becomes too weak to support bound state solutions. We have
found that together with these solutions a separate resonance branch appears
which is not connected smoothly with the bound state solutions. At small values
of constituent quark mass, $m\sim 200$ MeV, it corresponds to the physical
vector meson resonance solution in the quark-continuum region. The $a_1$ and
$\sigma$ resonances are also discussed.


title:
Multiple diffraction model for proton-proton elastic scattering and
  total cross section extrapolations to cosmic-ray energies

abstract:
  We analyse pp elastic scattering data at the highest accelerator energy
region (between 10 and 63 GeV) through a multiple diffraction approach. The use
of Martin's formula in a model developed earlier is substituted by the
introduction of a complex elementary (parton-parton) amplitude. With this the
total cross section and the real part of the hadronic amplitude may be
simultaneously investigated and, with the exception of the diffraction minimum
at some ISR energies, a satisfactory description of all experimental data is
obtained. Total cross sections extrapolations to cosmic-ray energies (above 6
TeV) show agreement with the reanalysis of the Akeno data performed by N. N.
Nikolaev and also with Gaisser, Sukhatme and Yodh results, leading to the
prediction 147 mb for the total cross section at 16 TeV. Physical
interpretations and critical remarks concerning our parametrizations and
results are also presented and discussed.


title: Theory of CP Violation

abstract:
  CP violation in K and B decays is reviewed in the Standard Model (SM) and
beyond the SM. In K decays, one is seeking first evidence for CP violation in
direct $K\to \pi\pi$ decays. This would not give a precise quantitative test
for the present explanation of CP violation in terms of a phase in the
Cabibbo-Kobayashi-Maskawa (CKM) matrix. Such tests are provided by a variety of
CP asymmetries in neutral and charged B decays. Certain features,
characterizing CP violation beyond the standard model, are outlined in the B
meson system.


title:
Physics Backgrounds to Supersymmetric Signals with Two Photons and
  Missing Mass at LEP

abstract:
  We calculate the event rates for the Standard Model production of two photons
plus missing mass through the process electron positron to gamma gamma nu
nubar, where nu is any of the three neutrino flavors, at LEP energies. This
process can be a background to new physics signatures, such as that expected
from supersymmetry with a higgsino or gravitino LSP. The missing mass
distribution is presented for several sets of kinematic cuts at beam energies
of 161, 172, 184, and 194 GeV. The effect of initial state photon radiation is
also studied, and is found to be significant, approximately doubling the event
rates.


title: Physics with e^+e^- Linear Colliders

abstract:
  We describe the physics potential of $e^+e^-$ linear colliders in this
report. These machines are planned to operate in the first phase at a center-of
--mass energy of 500 GeV, before being scaled up to about 1 TeV. In the second
phase of the operation, a final energy of about 2 TeV is expected. The machines
will allow us to perform precision tests of the heavy particles in the Standard
Model, the top quark and the electroweak bosons. They are ideal facilities for
exploring the properties of Higgs particles, in particular in the intermediate
mass range. New vector bosons and novel matter particles in extended gauge
theories can be searched for and studied thoroughly. The machines provide
unique opportunities for the discovery of particles in supersymmetric
extensions of the Standard Model, the spectrum of Higgs particles, the
supersymmetric partners of the electroweak gauge and Higgs bosons, and of the
matter particles. High precision analyses of their properties and interactions
will allow for extrapolations to energy scales close to the Planck scale where
gravity becomes significant. In alternative scenarios, like compositeness
models, novel matter particles and interactions can be discovered and
investigated in the energy range above the existing colliders up to the TeV
scale. Whatever scenario is realized in Nature, the discovery potential of
$e^+e^-$ linear colliders and the high-precision with which the properties of
particles and their interactions can be analysed, define an exciting physics
programme complementary to hadron machines.


title: Evolution of Gluon Spin in the Nucleon

abstract:
  We examine the $Q^2$ evolution of gluon polarization in polarized nucleons.
As is well known, the evolution of $\alpha_s \Delta G(Q^2)$ is negligible for
typical momentum transfer variations found in experimental deep inelastic
scattering. As $\alpha_s$ increases, however, the leading nonzero term in the
evolution equation for the singlet first moment reduces the magnitude of the
gluon spin. At low $Q^2$ the term $\alpha_s \Delta G$ can vanish, and
ultimately become negative. Thus, low energy model calculations yielding
negative $\Delta G$ are not necessarily in conflict with experimental evidence
for positive gluon polarization at high $Q^2$.


title: Constraints on Neutralino Dark Matter from LEP 2 and Cosmology

abstract:
  A significant lower limit on the mass of the lightest neutralino \chi can be
obtained by combining the results from sparticle searches at LEP at
centre-of-mass energies up to 172 GeV with cosmological considerations, if it
is assumed that the \chi is stable. Exclusion domains from slepton searches
close m_\chi \sim 0 loopholes that were left open by previous lower-energy LEP
searches for charginos and neutralinos, leading to the lower limit $m_\chi \ga
17$ GeV. The constraints on supersymmetric parameter space are strengthened
significantly if LEP constraints on supersymmetric Higgs bosons are taken into
account, and further if the relic neutralino density is required to fall within
the range favoured by astrophysics and cosmology. These bounds are considerably
strengthened if universality at the GUT scale is assumed for soft
supersymmetry-breaking scalar masses, including those of the Higgs bosons. In
this case, the Higgs searches play a dramatic role, and we find that m_\chi \ga
40 GeV. Furthermore, we find that if tan\beta \la 1.7 for \mu<0, or tan\beta
\la 1.4 for \mu >0, the cosmological relic density is too large for all values
of m_\chi.


title: Higher Twist Effect in Inclusive Quarkonium Photoproduction

abstract:
  We analyze higher twist effect in photoproduction of quarkonium, where the
quarkonium is a spin-triplet, S-wave state. We find that the nonperturbative
effect of next-to-leading twist is contained in three correlation functions
related to the initial hadron and some of the effect of next-to-leading twist
is only suppressed by the inverse of the mass square of the quarkonium. A naive
estimation indicates that the effect can be significant for charmonium. In the
analysis we only take the leading order in the small velocity expansion for the
nonperturbative parts related to the quarkonium. Possible corrections from
higher orders, especially, corrections from color-octet states are discussed in
detail.


title: Perturbative Prediction for Parton Fragmentation into Heavy Hadron

abstract:
  By expanding functions of parton fragmentation into a heavy hadron in the
inverse of the heavy quark mass $m_Q$ we attempt to factorize them into
perturbative- and nonperturbative parts. In our approach the nonperturbative
parts can be defined as matrix elements in heavy quark effective theory, the
shape of the functions is predicted by perturbative QCD. In this work we
neglect effect at order of $m_Q^{-2}$ and calculate the perturbative parts at
one-loop level for heavy quark- and gluon fragmentation. We compare our results
from leading log approximation with experimental results from $e^+e^-$
colliders and find a deviation below or at 10% level. Adding effect of higher
order in $\alpha_s$ it can be expected to reduce the deviation. The size of
matrix elements appearing at the order we consider for several types of heavy
hadrons is determined.


title:
An Analysis of Diagonal and Non-diagonal QCD Sum Rules for Heavy Baryons
  at Next-to-Leading Order in \alpha_S

abstract:
  We consider diagonal and non-diagonal QCD sum rules for the ground state
heavy baryons to leading order in $1/m_Q$ and at next-to-leading order in
$\alpha_S$. In the non-diagonal case we evaluate the eight different two-loop
diagrams which determine the perturbative $\alpha_S$-corrections to the Wilson
coefficient of the quark condensate in the Operator Product Expansion. The QCD
corrections to the non-diagonal sum rules are moderate compared to the QCD
corrections in the diagonal case. We also consider constituent type sum rules
using constituent type interpolating currents. The obtained results are in
reasonable agreement with the corresponding results obtained in the diagonal
case. As central values for the bound state energies we find $m(\Lambda_Q)-m_Q
= 760 MeV$ and $m(\Sigma_Q)-m_Q = 940 MeV$. The central values for the residues
are given by $F(\Lambda_Q) = 0.030 GeV^3$ and $F(\Sigma_Q) = 0.038 GeV^3$.


title: Successful D-term Inflation with moduli

abstract:
  We examine a natural extension of D-term inflation and construct a successful
model. General type of the D-term potential is shown to produce successful
inflation with appropriate COBE normalization. The effect of the dilaton shift
at the inflation period is taken into account.


title: Finite SUSY GUT Revisited

abstract:
  We analyze finite supersymmetric SU(5) GUT taking into account the problem in
the Higgs potential and threshold corrections to gauge and Yukawa couplings at
GUT and SUSY scales which is important in case of large $\tan \beta$ model. We
find that even with these finiteness conditions, which are very restrictive,
there are parameter regions where low-energy experimental values are
consistently reproduced and the Higgs potential actually realizes both
constraints for large $\tan \beta$ and radiative electroweak symmetry breaking,
provided that a free parameter is introduced in the boundary condition of the
Higgs mixing mass parameter.


title:
Phenomenological aspects of a Fermiophobic SU(2)xSU(2)xU(1) extension of
  the Standard Model

abstract:
  We consider an extension of the standard electroweak theory with gauge group
$SU(2)_L \times SU(2)_R \times U(1)_{\tilde{Y}}$, where the gauge bosons of the
extra $SU(2)_R$ factor do not couple to ordinary fermions. We show that
precision electroweak data and flavour physics provide quite stringent indirect
constraints on its parameter space, but still allow for relatively light
non-standard gauge and Higgs bosons. We then consider the model phenomenology
at high-energy colliders, and observe that in the gauge boson sector present
bounds and possible future signals are dominated by $Z'$ production. In
summary, indirect constraints on the charged gauge boson sector are so tight
that observable new effects must be connected either with the neutral gauge
boson sector or with the extended Higgs sector of the model.


title:
The neutrino magnetic moment and time variations of the solar neutrino
  flux

abstract:
  The present status of the neutrino magnetic moment solutions of the solar
neutrino problem is summarized. After a brief review of the basics of the
neutrino spin and spin-flavor precession I discuss the experimental data and
show how the neutrino resonant spin-flavor precession (RSFP) mechanism can
naturally account for sizeable time variations in the Homestake signal and no
observable time variations in the Kamiokande and gallium experiments. Fits of
the existing data and predictions for the forthcoming solar neutrino
experiments are also discussed. In the last section I summarize the objections
to the RSFP mechanism that are frequently put forward and comment on them.


title: Classical Statistical Mechanics and Landau Damping

abstract:
  We study the retarded response function in scalar $\phi^4$-theory at finite
temperature. We find that in the high-temperature limit the imaginary part of
the self-energy is given by the classical theory to leading order in the
coupling. In particular the plasmon damping rate is a purely classical effect
to leading order, as shown by Aarts and Smit. The dominant contribution to
Landau damping is given by the propagation of classical fields in a heat bath
of non-interacting fields.


title: Rho-Omega Mixing and Direct CP Violation in Hadronic B-Decays

abstract:
  The extraction of CKM-matrix-element information from hadronic B-decays
generally suffers from discrete ambiguities, hampering the diagnosis of physics
beyond the Standard Model. We show that a measurement of the rate asymmetry,
which is CP-violating, in
$B^{\pm}\to\rho^{\pm}\rho^0(\omega)\to\rho^{\pm}\pi^+\pi^-$, where the
invariant mass of the $\pi^+\pi^-$ pair is in the vicinity of the $\omega$
resonance, can remove the mod($\pi$) uncertainty in $\alpha\equiv arg [-V_{td}
V_{tb}^\ast/(V_{ud}V_{ub}^\ast)]$ present in standard analyses.


title:
Hadron Fragmentation Functions and Leading Particle Effects in Hadronic
  Z0 Decays: New Results from SLD

abstract:
  We have measured the differential cross sections for the production of
$\pi^{\pm}, K^{\pm}, K^0, K^{*0}, \Phi, p$ and $\Lambda$ in hadronic $Z^0$
decays and in subsets of flavor-tagged $Z^0 \to$ light quark ($u \bar{u}$, $d
\bar{d}$, or $s \bar{s}$), $Z^0 \to c \bar{c}$ and $Z^0 \to b \bar{b}$ events.
Charged hadrons were identified with the SLD Cherenkov ring imaging detector.
The vertex detector was employed to select flavor enriched samples and the
polarized electron beam from SLC was used to tag quark and anti-quark jets. We
observe a flavor dependence in the hadron fragmentation functions. We present
evidence for leading particle production in hadronic decays of the $Z^{0}$
boson to light-flavor jets and a direct measurement of the strangeness
suppression factor $\gamma_s$.


title: Spectral Fluctuations of the QCD Dirac Operator

abstract:
  Recently, QCD Dirac spectra have been obtained for reasonably large lattices.
We argue that correlations of these spectra are universal and can be obtained
from a random matrix model with the global symmetries of QCD. Analytical
arguments are presented to support this claim. Detailed comparisons with
lattice results are made. We analyze spectral correlations in the bulk of the
spectrum and find that long range fluctuations are strongly suppressed in
complete agreement with random matrix theory. We study the valence quark mass
dependence of the lattice QCD Dirac operator showing that the average spectral
density near zero virtuality is given by chiral random matrix theory. This
agrees with recent lattice calculations of the microscopic spectral density. of
this lecture, we introduce a schematic random matrix model for the chiral phase
transition at nonzero chemical potential. We consider both real, complex and
quaternion real matrix elements. We find a remarkable triality for the
distribution of of the eigenvalues in the complex plane. In particular, this
elucidates the nature of the quenched approximation in each case.


title:
Spontaneous Magnetization of Axion Domain Wall and Primordial Magnetic
  Field

abstract:
  We show that axion domain walls gain spontaneous magnetization in early
universe by trapping either electrons or positrons with their spins polarized.
The reason is that the walls produces an attractive potential for these
particles. We argue that the wall bounded by an axionic superconducting string
leaves a magnetic field after its decay. We obtain a field $\sim 10^{-23}$
Gauss on the scale of horizon at the recombination.


title: Gauge Unification and Dynamical Supersymmetry Breaking

abstract:
  Under the assumption that all the gauge groups in supersymmetric theories
unify at the fundamental scale, the numbers and the mass scales of messenger
quarks and leptons, as well as the beta-function coefficient of the sector for
dynamical supersymmetry breaking are constrained depending on various gauge
mediation mechanisms. For this, we use one-loop renormalization group equations
and draw constraints on the scales in each gauge mediation model.


title:
Mass Hierarchy and Mixing as Results of Simultaneous Dynamical Breaking
  of Chiral and Flavor Symmetries

abstract:
  If the hierarchy of quark masses comes out of simultaneous dynamical chiral
and flavor symmetry breakings, it is inevitably accompanied by the flavor
mixing. Therefore, these phenomena, independent in the standard model and in
many of its generalizations, become related since they appear out of the same
dynamics. The features of that high energy dynamics may be investigated via
accordance with observed mass hierarchy and mixing.


title:
Evolution Kernels for Light-Ray Operators: Twist 2 and Twist 3
  Contributions

abstract:
  The general evolution kernels of the twist 2 light-ray operators for
unpolarized and polarized deep inelastic scattering are calculated in ${\cal
O}(\alpha_s)$. From these evolution kernels a series of special evolution
equations can be derived, among them the Altarelli-Parisi equations and the
evolution equation for the meson wave function. In the case of twist 3 the
results of Balitzki and Braun are confirmed.


title: 1/Q^2 terms and Landau singularity

abstract:
  Standard power-behaved contributions in QCD arising from non-perturbative
effects at low scale can be described, as shown by Dokshitzer, Marchesini and
Webber, with the notion of an infrared regular effective coupling. In their
approach, a non-perturbative contribution to the coupling, essentially
restricted to low scales, parametrizes the non-perturbative power corrections.
I argue that their framework naturally allows for another type of power
contributions, arising from short distances (hence unrelated to renormalons and
the operator product expansion) which appear in the process of removing the
Landau singularity present in perturbation theory. A natural definition of an
infrared finite perturbative coupling is suggested within the dispersive
method. Implications for the tau hadronic width, where $O(1/Q^2)$ contributions
can be generated, are pointed out.


title: CP Violation in the Aspon Model

abstract:
  The aspon model spontaneously breaks CP symmetry and makes qualitatively
different predictions for CP asymmetries in B decay from the KM mechanism of
the Standard Model. It further predicts the existence of the aspon gauge boson
and of heavy long-lived quarks, both lying below 1TeV in mass.


title: Delta I=3/2 and Delta S =2 Hyperon Decays in Chiral Perturbation Theory

abstract:
  We study the Delta I =3/2 and Delta S =2 amplitudes for hyperon decays of the
form (B to B(prime) pion) at lowest order in chiral perturbation theory. At
this order, the Delta I=3/2 amplitudes depend on only one constant. We extract
the value of this constant from experiment and find a reasonable description of
these processes within experimental errors. The same constant determines the
Delta S =2 transitions which, in the standard model, are too small to be
observed. We find that new physics with parity odd Delta S=2 interactions can
produce observable rates in hyperon decays while evading the bounds from K0 -
K0(bar) mixing.


title:
Possible Explanation for $E > 10^{20}$ eV Air Showers with
  Flavour-Changing Neutral Currents

abstract:
  Air showers observed with $E > 10^{20}$ eV pose a problem since protons at
such energies cannot survive a long journey through the 2.7 K microwave
background. It is suggested that they are initiated instead by neutrinos which
become strongly interacting through exchanges of gauge bosons associated with
generation-changing neutral currents, a suggestion which is supported by
calculations in a dualized standard model recently proposed. In turn, the
suggestion bounds the mass of the gauge bosons and gives estimates for the
branching ratios of FCNC s, c, b, and t meson decays which are accessible to
experiments now being planned.


title: Cosmic String Zero Modes and Multiple Phase Transitions

abstract:
  The zero modes and current carrying capability of a cosmic string formed at
one phase transition can be modified at subsequent phase transitions. A new,
generalised index theorem is derived that is applicable to theories with
multiple phase transitions. This enables us to investigate the fate of string
zero modes during sequences of phase transitions in a variety of models.
Depending on the couplings that the breaking introduces, the zero modes may be
destroyed and the superconductivity of the string removed, and thus vortons
dissipate. We discuss the features of the theory that are required to produce
this behaviour and consider the implications of spectral flow.


title:
Nonfactorization and Final State Interactions in (B, B_s) --> \psi P and
  \psi V Decays

abstract:
  Available experimental data on decay rates for B --> \psi K, and decay rates
and transversity amplitudes for B --> \psi K^* are used to investigate
nonfactorization contributions in these decays using five different theoretical
models for the formfactors. Using the knowledge on nonfactorization so gained,
we study the processes B_s --> \psi (\eta, \eta'), B_s --> \psi \phi and B -->
\psi(2S) K^*. We find that present experimental data for the last two processes
are consistent with the predictions of most of the models considered.


title: Running coupling and Borel singularities at small x

abstract:
  Starting from the dipole representation of small-$x$ evolution we implement
the running of the coupling in a self-consistent way. This results in an
evolution equation for the dipole density in Borel $(b)$ space. We show that
the Borel image of the dipole density is analytic in the neighbourhood of $b=0$
and that it is equal to the BFKL solution at $b=0$. We study the Borel
singularity structure of the dipole cascade emanating from a virtual photon at
small $x$ and find a branch cut on the positive $b$-semiaxis starting at $b=1/
\beta_0$. This indicates the presence of $1/Q^2$ power corrections to the
small-$x$ structure functions. Finally we present numerical results in the
context of D.I.S.


title: Semileptonic B decays to excited charmed mesons

abstract:
  Exclusive semileptonic B decays into excited charmed mesons are investigated
at order $\Lambda_{QCD}/m_Q$ in the heavy quark effective theory. Differential
decay rates for each helicity state of the four lightest excited $D$ mesons
($D_1$, $D_2^*$, $D_0^*$, and $D_1^*$) are examined. At zero recoil,
$\Lambda_{QCD}/m_Q$ corrections to the matrix elements of the weak currents can
be written in terms of the leading Isgur-Wise functions for the corresponding
transition and meson mass splittings. A model independent prediction is found
for the slope parameter of the decay rate into helicity zero $D_1$ at zero
recoil. The differential decay rates are predicted, including
$\Lambda_{QCD}/m_Q$ corrections with some model dependence away from zero
recoil and including order $\alpha_s$ corrections. Ratios of various exclusive
branching ratios are computed. Matrix elements of the weak currents between $B$
mesons and other excited charmed mesons are discussed at zero recoil to order
$\Lambda_{QCD}/m_Q$. These amplitudes vanish at leading order, and can be
written at order $\Lambda_{QCD}/m_Q$ in terms of local matrix elements.
Applications to $B$ decay sum rules and factorization are presented.


title: A Note on CP Invariance and Rephasing Invariance

abstract:
  CP invariance condition and rephasing invariance in KM scheme of CP violation
is discussed. The CP violation measures in B physics, corresponding to the
three angles of unitarity triangle are given in rephasing invariant form. With
the obtained results it is shown that the sum of the three CP angles to be
measured at B factories becomes $\pi$ even if the Kobayashi-Maskwa matrix is
not a $3\times 3$ unitary matrix under reasonable assumptions.


title:
CP-Violation and Baryogenesis in The Low Energy Minimal Supersymmetric
  Standard Model

abstract:
  In the context of the minimal supersymmetric extension of the Standard Model
the effect of a realistic wall profile is studied. It has been recently showed
that in the presence of light stops the electroweak scale phase transition can
be strong enough for baryogenesis. In the presence of non-trivial CP-violating
phases of left-handed mixing terms and Higgsino mass, the largest $n_B/s$ is
created when Higgsino and gaugino mass parameters are degenerate, $\mu = M_2$.
In the present paper we show that realistic wall profiles suppress the
generated baryon number of the universe, so that quite a stringent bound
$|\sin\phi_\mu | \gsim 0.2$ for $\mu$-phase $\phi_\mu$ can be inferred.


title: Total $\gamma^{\star}\gamma^{\star}$ cross section and the BFKL pomeron

abstract:
  In the framework of the dipole picture of the BFKL pomeron we discuss a few
possibilities of calculating the total $\gamma^{\star}\gamma^{\star}$ cross
section of the virtual photons. We argue that the existing successful fits of
the dipole picture formulae to the measured structure functions $F_2(Q^2,x)$
favor one of the possible extensions of the dipole picture of the BFKL pomeron
formulated recently by one of us.


title:
Diagonalization of Coupled Scalars and its Application to the
  Supersymmetric Neutral Higgs Sector

abstract:
  We introduce a momentum dependent mixing angle $\alpha(p^2)$ which allow us
to diagonalize at any external momentum $p$ the one-loop corrected inverse
propagator matrix of two coupled scalar fields while keeping the full momentum
dependence in the self energies. We compare this method with more traditional
techniques applied to the diagonalization of coupled scalars at the one-loop
level. This method is applied to the CP-even Higgs sector of the Minimal
Supersymmetric Model, defining the momentum dependent mixing angle
$\alpha(p^2)$, and calculating the two CP-even Higgs masses and the mixing
angle at these two scales. We compare the results obtained in this way with
alternative techniques. We make explicit the relation between $\alpha(p^2)$ and
the running mixing angle. We find differences between the mixing angle
calculated with our method and the one calculated with more traditional
methods, and these differences are relevant for Higgs searches at LEP2.


title: Remarks on Higgs boson production

abstract:
  We demonstrate that Higgs boson production in fusion processes is accompanied
by large azimuthal asymmetry. This asymmetry can be used to facilitate
detection of Higgs boson events. We also demonstrate that the double Higgs
boson production at threshold is a very appropriate process to test the
existence of new physics at higher energy.


title:
Inclusive single particle density in configuration space from the
  QCD-cascade in DLA approximation

abstract:
  The structure of the QCD gluonic cascade in configuration space is
investigated. The explicit form of the inclusive single particle density in
configuration space transverse coordinates is derived in the double logarithmic
approximation (DLA) of QCD. The possible simplification of the multiparton
density matrix formalism for DLA approach is found and discussed.


title: Two flavor chiral phase transition from nonperturbative flow equations

abstract:
  We employ nonperturbative flow equations to compute the equation of state for
two flavor QCD within an effective quark meson model. This yields the
temperature and quark mass dependence of quantities like the chiral condensate
or the pion mass. A precision estimate of the universal critical equation of
state for the three-dimensional O(4) Heisenberg model is presented. We
explicitly connect the O(4) universal behavior near the critical temperature
and zero quark mass with the physics at zero temperature and a realistic pion
mass. For realistic quark masses the pion correlation length near T_c turns out
to be smaller than its zero temperature value.


title: A Positive Test for Fermi-Dirac Distributions of Quark-Partons

abstract:
  By describing a large class of deep inelastic processes with standard
parameterization for the different parton species, we check the characteristic
relationship dictated by Pauli principle: broader shapes for higher first
moments. Indeed, the ratios between the second and the first moment and the one
between the third and the second moment for the valence partons is an
increasing function of the first moment and agrees quantitatively with the
values found with Fermi-Dirac distributions.


title: Anomalies and decoupling of charginos and neutralinos in the MSSM

abstract:
  We study the contribution of charginos and neutralinos of the Minimal SUSY
extension of the Standard model (MSSM) to the 1-loop vertices ZAA, ZZA, ZZZ,
and examine the related cancellation of anomalies. It is found that when the
SUSY parameter \mu satisfies |\mu| >> M,M', m_W, the couplings of charginos and
neutralinos with the gauge bosons become purely vectorial, and then their
contribution to the amplitudes for ZAA, ZZA and ZZZ vanish, which implies that
this sector of the MSSM does not generate a Wess-Zumino term. We evaluate also
the contribution of charginos and neutralinos to the \rho parameter, and find
that \rho=0 in the large-\mu limit.


title: Quantum Chromodynamics and Other Field Theories on the Light Cone

abstract:
  We discuss the light-cone quantization of gauge theories as a calculational
tool for representing hadrons as QCD bound-states of relativistic quarks and
gluons, and also as a novel method for simulating quantum field theory on a
computer. The light-cone Fock state expansion of wavefunctions provides a
precise definition of the parton model and a general calculus for hadronic
matrix elements. We present several new applications of light-cone Fock
methods, including calculations of exclusive weak decays of heavy hadrons, and
intrinsic heavy-quark contributions to structure functions. Discretized
light-cone quantization, is outlined and applied to several gauge theories. We
also discuss the construction of the light-cone Fock basis, the structure of
the light-cone vacuum, and outline the renormalization techniques required for
solving gauge theories within the Hamiltonian formalism on the light cone.


title: Constraints on the parameters of the Left Right Mirror Model

abstract:
  We study some phenomenological constraints on the parameters of a left right
model with mirror fermions (LRMM) that solves the strong CP problem. In
particular, we evaluate the contribution of mirror neutrinos to the invisible Z
decay width (\Gamma_Z^{inv}), and we find that the present experimental value
on \Gamma_Z^{inv}, can be used to place an upper bound on the Z-Z' mixing angle
that is consistent with limits obtained previously from other low-energy
observables. In this model the charged fermions that correspond to the standard
model (SM) mix with its mirror counterparts. This mixing, simultaneously with
the Z-Z' one, leads to modifications of the \Gamma(Z --> f \bar{f}) decay
width. By comparing with LEP data, we obtain bounds on the standard-mirror
lepton mixing angles. We also find that the bottom quark mixing parameters can
be chosen to fit the experimental values of R_b, and the resulting values for
the Z-Z' mixing angle do not agree with previous bounds. However, this
disagreement disappears if one takes the more recent ALEPH data.


title: Beyond the Standard Model

abstract:
  These lectures constitute a short course in `Beyond the Standard Model' for
students of experimental particle physics. I discuss the general ideas which
guide the construction of models of physics beyond the Standard Model. The
central principle, the one which most directly motivates the search for new
physics, is the search for the mechanism of the spontaneous symmetry breaking
observed in the theory of weak interactions. To illustrate models of
weak-interaction symmetry breaking, I give a detailed discussion of the idea of
supersymmetry and that of new strong interactions at the TeV energy scale. I
discuss experiments that will probe the details of these models at future pp
and e+e- colliders. [Lectures presented at the 1996 European School of
High-Energy Physics.]


title: Physical Coupling Schemes and QCD Exclusive Processes

abstract:
  I discuss application of the BLM method to obtain commensurate scale
relations connecting QCD exclusive amplitudes to other observables, in
particular the heavy quark potential.


title:
Semileptonic six fermion processes at future $e^+ e^-$ colliders: signal
  and irreducible background for top and WWZ physics

abstract:
  We compute several total and differential cross sections relevant to top and
WWZ physics at future $e^+e^-$ colliders taking into account the full set of
Feynman diagrams for six fermion final states. We also include in our
calculations initial state radiation and beamstrahlung effects, and the most
important QCD corrections in an approximate (naive) form. We compare such a
complete approach with "production x decay" approximation and we suggest that
in many physical studies the former is needed.


title: Review from theoretician

abstract:
  The talks presented at the conference are summarized from an angle of a
particle theorist. After presenting a personal impression on the conference,
particular emphasis is placed on the spin structure of nucleons and symmetry
breaking test.


title: New Physics at HERA: Implications for e+e- Scattering at LEP2

abstract:
  The impact of virtual leptoquark or R-parity breaking squark exchange as well
as generic contact interactions on the production of quark-antiquark pairs in
$e^+e^-$ annihilation, in particular at LEP2, is summarized. An exciting
possibility of sneutrino formation in $e^+e^-$ scattering is also mentioned.


title:
Non-perturbative Renormalization Group Approach to Dynamical Chiral
  Symmetry Breaking in Gauge Theories

abstract:
  We analyze the dynamical chiral symmetry breaking in gauge theories solely by
the non-perturbative renormalization group, without recourse to the
Schwinger-Dyson method. First, we briefly review the basic notions and
formulation, and clarify its great feature that it gives a systematic
approximation scheme without any divergent series nor serious gauge dependence,
compared to other perturbative and non-perturbative methods. Then we apply this
new method to QED and QCD to find that our lowest level approximation improves
the ladder Schwinger-Dyson equation results in a gauge independent way. We get
the chiral phase structures and the critical exponents in the fixed gauge
coupling analysis, and also calculate the chiral condensates in case of running
QCD.


title:
Integral Relations for Twist 2 abd Twist 3 Contributions to Polarized
  Structure Functions

abstract:
  We discuss the relations between the twist 2 and twist 3 contributions to
polarized deep-inelastic scattering structure functions both for neutral and
charged current interactions which are predicted by the operator product
expansion in lowest order in QCD.


title:
Threshold Resummation of the Total Cross Section for Heavy Quark
  Production in Hadronic Collisions

abstract:
  We discuss calculations of the inclusive total cross section for heavy quark
production at hadron collider energies within the context of perturbative
quantum chromodynamics, including resummation of the effects of initial-state
soft gluon radiation to all orders in the strong coupling strength. We resum
the universal leading-logarithm contributions, and we restrict our integrations
to the region of phase space that is demonstrably perturbative. We include a
detailed comparison of the differences between ours and other methods. We
provide predictions of the physical cross section as a function of the heavy
quark mass in proton-antiproton reactions at center-of-mass energies of 1.8 and
2.0 TeV, and we discuss estimated uncertainties.


title:
Nonequilibrium inflaton dynamics and reheating: Back reaction of
  parametric particle creation and curved spacetime effects

abstract:
  We present a detailed and systematic analysis of the nonperturbative,
nonequilibrium dynamics of a quantum field in the reheating phase of
inflatonary cosmology, including full back reactions of the quantum field on
the curved spacetime, as well as the fluctuations on the mean field. We use the
O(N) field theory with unbroken symmetry in a spatially flat FRW universe to
study the dynamics of the inflaton in the post-inflaton, preheating stage.
Oscillations of the inflaton's zero mode induce parametric amplification of
quantum fluctuations, resulting in a rapid transfer of energy to the
inhomogeneous modes of the inflaton field. We adopt the coupled nonperturbative
equations for the mean field and variance derived in a preceding paper
[gr-qc/9706001] by means of a two-particle-irreducible (2PI), closed-time-path
(CTP) effective action for curved spacetime while specialized to leading order
in the 1/N expansion. Adiabatic regularization is employed. The renormalized
dynamical equations are evolved numerically from initial data which are generic
to the end state of slow roll in many inflatonary cosmological scenarios. The
initial conditions consist of a large-amplitude, quasiclassical, oscillating
mean field, and a variance given by the de Sitter-invariant vacuum. We find
that for sufficiently large initial mean-field amplitudes in this model, the
parametric resonance effect alone (in a collisionless approximation) is not an
efficient means to "preheat" the quantum field. For small initial mean-field
amplitude, damping of the mean field via parametric amplification of quantum
fluctuations is seen to occur. Our results indicate that the self-consistent
dynamics of spacetime plays an important role in determining the physics of the
post-inflatonary Universe.


title: Nuclear Transparency in a Relativistic Quark Model

abstract:
  We examine the nuclear transparency for the quasi-elastic ($e, e'p$) process
at large momentum transfers in a relativistic quantum-mechanical model for the
internal structure of the proton, using a relativistic harmonic oscillator
model. A proton in a nuclear target is struck by the incident electron and then
propagates through the residual nucleus suffering from soft interactions with
other nucleons. We call the proton "dynamical" when we take into account of
internal excitations, and "inert" when we freeze it to the ground state. When
the dynamical proton is struck with a hard (large-momentum transfer)
interaction, it shrinks, i.e., small-sized configuration dominates the process.
It then travels through nuclear medium as a time-dependent mixture of intrinsic
excited states and thus changing its size. Its absorption due to the soft
interactions with nuclear medium depends on its transverse-size. Since the
nuclear transparency is a measure of the absorption strength, we calculate it
in our model for the dynamical case, and compare the results with those for the
inert case. The effect of the internal dynamics is observed, which is in accord
with the idea of the "color transparency". We also compare our results with the
experimental data in regard of $q^2$-dependence as well as A-dependence, and
find that the A-dependence may reveal the color-transparency effect more
clearly.


title: Lambda^2-contribution to the condensate in lattice gauge theory

abstract:
  We present some evidence that in Lattice Gauge Theory the condensate contains
a non-perturbative contribution proportional to $\Lambda^2$, the square of the
physical scale. This result is based on an analysis of the Wilson loop
plaquette expectation from Monte Carlo simulations and its perturbative
expansion computed to eight loops. The analysis is not fully conclusive since
the calculations are done on a finite lattice and one needs an extrapolation to
infinite lattice. It has been recently suggested that in the gluon condensate a
$\Lambda^2$-contribution could be present coming from the large momentum
behaviour of the running coupling and not connected to operator product
expansion.


title: Jet Investigations Using the Radial Moment

abstract:
  We define the radial moment, <r>, for jets produced in hadron-hadron
collisions. It can be used as a tool for studying, as a function of the jet
transverse energy and pseudorapidity, radiation within the jet and the quality
of a perturbative description of the jet shape. We also discuss how
non-perturbative corrections to the jet transverse energy affect <r>.


title: Updated Running Quark Mass Values

abstract:
  The running quark masses at various energy scales are evaluated by using the
mass renormalization equations systematically. Also, those at energy scales
higher than m_Z are evaluated by using the evolution equations of Yukawa
coupling constants for the standard model with a single Higgs boson.


title:
Fermion masses, neutrino mixing and CP violation from the anti-grand
  unification model

abstract:
  The fermion masses and mixing angles are fitted using only 3 free parameters
in a non-supersymmetric extension of the Standard Model, with new approximately
conserved chiral gauge quantum numbers broken by a set of Higgs fields. The
fundamental mass scale of this anti-grand unification model is given by the
Planck mass. We also calculate neutrino mixing angles and masses, as well as CP
violation from the CKM matrix. A good fit is obtained to the observed fermion
masses but our predictions of the neutrino masses are too small to lead to any
observable neutrino oscillation effects claimed today, without introducing
another mass scale. We also give some arguments in support of this type of
model based on the observed fermion masses.


title: Evolution of Parton Distributions

abstract:
  I present a highly efficient method for evolving parton distributions in
perturbative QCD. The method allows evolving the parton distribution functions
according to any of the commonly-used truncations of the evolution equations
(which differ in their treatment of higher-order terms). I also give formul\ae\
for computing crossing functions within the method.


title: W-exchange and W-annihilation processes of B mesons

abstract:
  Using the PQCD method we calculate the W-exchange and the W-annihilation
processes of B mesons, which in general involve a charm quark or anti-quark in
the final state. The nonvanishing amplitudes of these processes are found to be
suppressed by a factor of $m_c/m_b$ compared to the tree or the time-like
penguin processes, but some of them are within the reach of observation at the
future B-factories, and $\bar B_d^0 \to D^+_s K^-$ whose branching ratio is
found to be $6.6 \times 10^{-6}$ can be found even before the B-factory era.
Comparisons with the results based on the BSW model are also given.


title: Borel singularities at small x

abstract:
  D.I.S. at small Bjorken $x$ is considered within the dipole cascade
formalism. The running coupling in impact parameter space is introduced in
order to parametrize effects that arise from emission of large size dipoles.
This results in a new evolution equation for the dipole cascade. Strong
coupling effects are analyzed after transforming the evolution equation in
Borel ($b$) space. The Borel singularities of the solution are discussed first
for the universal part of the dipole cascade and then for the specific process
of D.I.S. at small $x$. In the latter case the leading infrared renormalon is
at $b=1/\beta_0$ indicating the presence of $1/Q^2$ power corrections for the
small-$x$ structure functions.


title: CPT, Strings and Baryogenesis

abstract:
  In the context of string field theory, the possibility exists for the
spontaneous violation of Lorentz invariance and CPT. In this talk, we review
its status and some experimental constraints. We discuss the possibility that
stringy CPT violation could give rise to a mechanism in which baryogenesis
occurs in the early Universe in thermal equilibrium and show that this can
produce, under suitable circumstances, a baryon asymmetry equal to the observed
value.


title: Non-perturbative Expansion, Renormalons, and $\tau$ Decay

abstract:
  We analyze inclusive $\tau$ decay using a modified version of the $a$
expansion, a non-perturbative technique in which the effective coupling is
analytic in the infrared region. The modification involves renormalization
group improvement of the integrand in a spectral representation for the
D-function prior to implementing the $a$ expansion. The advantage of this
approach is that it enables us to monitor the structure of the induced power
corrections and to ensure that these are consistent with the operator product
expansion. Numerically the method agrees well with experiment: the comparison
is made with the physical quantity $R_Z$ using $R_\tau$ as input.


title: Top Pair Production at Hadron Colliders in non-minimal Standard Models

abstract:
  The cross section of top pair production in hadronic collisions to O(alpha
\alpha_s^2) is calculated within the General 2-Higgs-Doublet Model and the
Minimal Supersymmetric Standard Model. At the parton level the O(alpha)
one-loop corrections to the main production mechanisms, quark-antiquark
annihilation and gluon fusion, significantly modify the Born-cross sections: in
the threshold region \sqrt{\hat s}>~2 m_t they are enhanced up to 50 % and with
increasing cm energy \sqrt{\hat s}, they can be reduced by up to the same order
of magnitude. In a wide range of the parameter space of the models under
consideration the observable hadronic cross sections for top pair production at
the Tevatron and at the LHC are typically reduced by several percent (<~10 %)
compared to the lowest order result. In special regions of the parameter space,
that is in the vicinity of the threshold for the top quark decay t \to b H^+ ;
\tilde t \tilde \chi^0, the radiative corrections are considerably enhanced,
comparable in size to QCD effects.


title: What is the Force between Electrons?

abstract:
  The concept of the potential acting between charged particles is reviewed
within the framework of quantum electrodynamics. The one-photon and two-photon
exchange potentials V_1 \gamma and V_2 \gamma are discussed, with attention to
the following features: the dependence of V_2 \gamma on the choice of V_1
\gamma, the distinction between FGI (Feynman gauge inspired) and CGI (Coulomb
gauge inspired) potentials, and the dependence of the large-r behavior on these
choices. A summary of available results for two spin-0 particles, for a spin-0
and a spin 1/2 particle and for two spin-1/2 particles is given. The
application of such "scattering potentials" to the calculation of energy levels
of bound states is discussed.


title: Leptoquarks

abstract:
  In this review there is first a survey of the HERA data. Then we discuss the
theory response including querying the consistency of the data, compositeness,
contact terms, and leptoquarks including as a special case the R symmetry
violating squark. The SU(15) possibility for a light leptoquark is mentioned.
Finally there is a summary.


title: Toward the second stage at B factory

abstract:
  The measurement and precision at B physics experiment are reviewed by taking
into account of the numbers of B mesons to be produced in the future
experimental projects. With $10^9$ or more B mesons we will be able to fix the
parameters in Kobayashi-Maskawa matrix elements or find a signal of new
physics.


title: New Physics and CP Angles Measurement at B Factory

abstract:
  We have analyzed how much the $CP$ angles to be measured at B factories can
deviate from the geometrical ones defined in unitarity triangle under the
existence of new physics. The measurements are given in rephasing invariant
form. If KM matrix is not a $3\times 3$ and unitary matrix, $\tilde\phi_1$ and
$\tilde\phi_3$ is affected, and the value of $\tilde\phi_3$ depends on the
decay mode. The deviation is constrained to be less than the experimental
precision attained in the next decade by the available data of the magnitude of
KM matrix elements. Deviation of the sum of three angles from $\pi$ cannot be
detected unless new physics contributes significantly to $b$ decay or $D$ meson
system.


title:
Nonleptonic two-body charmed meson decays in an effective model for
  their semileptonic decays

abstract:
  We analyze $D \to P V$, $D \to PP$ and $D \to VV$ decays within a model
developed to describe the semileptonic decays $D \to V l \nu_l$ and $D\to P l
\nu_l$. This model combines the heavy quark effective Lagrangian and chiral
perturbation theory. We determine amplitudes for decays in which the direct
weak annihilation of the initial $D$ meson is absent or negligible, and in
which the final state interactions are small. This analysis reduces the
arbitrariness in the choice of model parameters. The calculated decay widths
are in good agreement with the experimental results.


title: Predictions for the eta_c-gamma transition form factor

abstract:
  The eta_c-gamma transition form factor is calculated in a model based on a
modified hard scattering approach to exclusive reactions, in which transverse
degrees of freedom are taken into account. For the eta_c-meson a distribution
amplitude of the Bauer-Stech-Wirbel type is used, where the two free
parameters, namely the decay constant f(eta_c) and the transverse size of the
wave function, are related to the Fock state probability and the width for the
two-photon decay Gamma[eta_c -> gamma gamma].


title:
$e^+e^- \to b \bar{b} u \bar{d} \mu^- \bar{\nu}_\mu$ with a $t\bar{t}$
  production

abstract:
  The cross section of $e^+e^- \to b \bar{b} u \bar{d} \mu^- \bar{\nu}_\mu$
process with a complete set of tree diagrams, 232 diagrams in the unitary
gauge, was calculated at the energy range of $\sqrt{s}$ = 340 - 500 GeV by
using GRACE system. A main contribution to the cross section comes from
$t\bar{t}$ production, where $t$ and $\bar{t}$ decay into $bu\bar{d}$ and
$\bar{b} \mu^- \bar{\nu}_{\mu}$, respectively. It was found that the
interference between the diagrams with $t\bar{t}$ production and those with
single-$t$ through $ WW $ pair production amounts to 10% at the $t \bar{t}$
threshold energy region. In the energy region above twice of the top quark
mass, more than 95% of the cross section comes from the $t\bar{t}$ diagrams.


title: Domain Walls and Vortices with Non-Symmetric Core

abstract:
  We review recent work on a new class of topological defects which possess a
nonsymmetric core. They arise in scalar field theories with global symmetries,
U(1) for domain walls and SU(2) for vortices, which are explicitly broken to
$Z_2$ and U(1) respectively. Both of the latter symmetries are spontaneously
broken. For a particular range of parameters both types of defect solutions are
shown to become unstable and decay to the well known stable walls and vortices
with symmetric cores.


title: Techniques for computing two-loop QCD corrections to b-->c transitions

abstract:
  We have recently presented the complete O(alpha_s^2) corrections to the
semileptonic decay width of the b quark at maximal recoil. Here we discuss
various technical aspects of that calculation and further applications of
similar methods. In particular, we describe an expansion which facilitates the
phase space integrations and the treatment of the mixed real-virtual
corrections, for which Taylor expansion does not work and the so-called eikonal
expansion must be employed. Several terms of the expansion are given for the
O(alpha_s^2) QCD corrections to the differential semileptonic decay width of
the b --quark at maximal recoil. We also demonstrate how the light quark loop
corrections to the top quark decay rate can be obtained using the same methods.
We briefly discuss the application of these techniques to the calculation of
the O(alpha_s^2) correction to zero recoil sum rules for heavy flavor
transitions.


title:
Fourier analysis of real-time, high-statistics solar neutrino
  observations

abstract:
  Solar neutrino oscillations with wavelengths comparable to the Earth-Sun
distance provide a viable explanations of the long-standing solar neutrino
deficit. They imply a time-dependent modulation of the solar neutrino flux due
to the eccentricity of the Earth orbit. Motivated by this testable prediction,
we propose a Fourier analysis of the signal observable in real-time, solar
neutrino experiments. We give the general expressions of the Fourier
coefficients and of their correlated uncertainties in the presence of
background. The expressions assume a particularly compact form in the case of
two-flavor neutrino oscillations in vacuum. We discuss the sensitivity to the
lowest harmonics of the new-generation, high-statistics experiments
SuperKamiokande, Sudbury Neutrino Observatory, and Borexino.


title: Testing various polarized parton distributions at RHIC

abstract:
  A very promising spin physics programme will be soon on the way at the BNL
Relativistic Heavy Ion Collider (RHIC). By studying the spin asymmetries for
various processes (single photon, single-jet and $W^{\pm}$ production), we will
compare the different predictions obtained using some sets of polarized parton
distributions, available in the recent literature. We will put some emphasize
on the analysis of the anticipated errors, given the event rates expected from
this high luminosity new machine and the current acceptance for the detector
systems at RHIC.


title:
Reconciling solar and terrestrial neutrino oscillation evidences with
  minimum sacrifice

abstract:
  The present possible evidences in favor of neutrino masses and mixings from
solar, atmospheric, and accelerator experiments cannot be all reconciled in a
three-family framework, unless some data are excluded. We grade all possible
three-family scenarios according to their compatibility with the available
data. A recently proposed scenario appears to emerge naturally as the most
likely solution to all oscillation evidences, with the only exception of the
angular dependence of multi-GeV atmospheric data in the Kamiokande experiment.
We describe in detail the status and the phenomenological implications of this
``minimum sacrifice'' solution.


title:
Large-order Behaviour of the QCD Adler D-function in Planar
  Approximation

abstract:
  We consider the structure of the leading ultra-violet (UV) renormalon
singularity associated with the QCD vacuum polarization Adler D-function, in
the approximation that only planar Feynman diagrams are retained. This ``planar
approximation'' results in some simplifications, in particular three of the
four potential contributions from four-fermion operators are shown to be
absent. We are able to obtain a fully normalized result for the leading
$n\to\infty$ behaviour of the portion of perturbative coefficients proportional
to $N_f^{n-r} N^r$, for SU(N) QCD with $N_f$ quark flavours.