title: Baryon Mass Splittings in Chiral Perturbation Theory

abstract:
  Baryon masses are calculated in chiral perturbation theory at the
one--loop-${\cal O}(p^3)$ level in the chiral expansion and to leading order in
the heavy baryon expansion. Ultraviolet divergences occur requiring the
introduction of counter--terms. Despite this neccessity, no knowledge of the
counter terms is required to determine the violations to the Gell--Mann Okubo
mass relation for the baryon octet or to the decuplet equal mass--spacing rule,
as all divergences cancel {\it exactly} at this order. For the same reason all
reference to an arbitrary scale $\mu$ is absent. Neither of these features
continue to higher--powers in the chiral expansion. We also discuss critically
the absolute neccessity of simultaneously going beyond the leading order heavy
baryon expansion, if one goes beyond the one-loop-${\cal O}(p^3)$ level. We
point out that these corrections in $1/M_B$ generate new divergences $\propto
m^4/M_{10}$. These divergences together with the divergences occuring in
one-loop-${\cal O}(p^4)$ graphs of chiral perturbation theory are taken care of
by the same set of counter--terms. Because of these unknown counter--terms one
cannot predict the baryon mass splittings at the one-loop-${\cal O}(p^4)$
level. We point out another serious problem of going to the one-loop-${\cal
O}(p^4)$ level. When the decuplet is off its mass--shell there are additional
$\pi N\Delta$ and $\pi\Delta\Delta$ interaction terms. These interactions
contribute not only to the divergent terms $\propto (m^4/M_{10})$, but also to
nonanalytic terms such as $\propto (m^4/M_{10}){\rm ln}(m/M_{10})$. Thus
without a knowledge of the coupling constants appearing in these interactions
one cannot carry out a consistent one-loop-${\cal O}(p^4)$ level calculation.


title: Chiral Symmetry Breaking for Fundamental Fermions

abstract:
  This talk gives an overview of the recent development in the study of
non-perturbative fermion-boson vertex in quenched QED towards achieving that
the fermion propagator satisfies the Ward-Takahashi identity, is
multiplicatively renormalizable, agrees with perturbation theory for weak
couplings and has a critical coupling for dynamical mass generation that is
strictly gauge independent. The use of such a vertex may lead to a realistic
calculation of t(tbar) condensates as the source of electroweak symmetry
breaking. (Talk given at The Advanced Study Institute on Frontiers in Particle
Physics, Cargese, Ajaccio, France, August 1-13, 1994.)


title: Equivalence Theorem and Probing the Electroweak Symmetry Breaking Sector

abstract:
  We examine the Lorentz non-invariance ambiguity in longitudinal weak-boson
scatterings and the precise conditions for the validity of the Equivalence
Theorem (ET). {\it Safe} Lorentz frames for applying the ET are defined, and
the intrinsic connection between the longitudinal weak-boson scatterings and
probing the symmetry breaking sector is analyzed. A universal precise
formulation of the ET is presented for both the Standard Model and the Chiral
Lagrangian formulated Electro-Weak Theories. It is shown that in electroweak
theories with strongly interacting symmetry breaking sector, the longitudinal
weak-boson scattering amplitude {\it under proper conditions} can be replaced
by the corresponding Goldstone-boson scattering amplitude in which all the
internal weak-boson lines and fermion loops are ignored.


title: Radiative Gaugino Masses

abstract:
  We investigate the possibility that gauginos are massless at tree level and
that the U(1) R-invariance is broken spontaneously by Higgs vevs, like the
chiral symmetry of quarks in the standard model, or else explicitly by
dimension 2 or 3 SUSY-breaking terms in the low energy effective Lagrangian.
Gluino and lightest neutralino masses then depend on only a few parameters. For
a SUSY-breaking scale <~ 400 GeV, the gluino and lightest neutralino have
masses typically in the range 1/10 ~ 2 1/2 GeV. On the other hand, for a
SUSY-breaking scale several TeV or larger, radiative contributions can yield
gluino and lightest neutralino masses of O(50-300) GeV and O(10-30) GeV,
respectively. As long as the Higgs vev is the only source of R-invariance
breaking, or if SUSY breaking only appears in dimension 2 terms in the
effective Lagrangian, the gluino is generically the lightest SUSY particle,
modifying the usual phenomenology in interesting ways.


title: Pion Fusion in Peripheral $pp$ Collisions

abstract:
  We estimate the cross section for quasi-elastic double pion exchange in high
energy proton-proton collisions. Total and elastic $\pi\pi$ cross sections are
calculated in an equivalent pion approximation, with pion-baryon vertices taken
from chiral perturbation theory.


title: A Renormalization-Group Approach to Finite-Temperature Mass Corrections

abstract:
  We illustrate how the reorganization of perturbation theory at finite
temperature can be economically cast in terms of the Wilson-Polchinski
renormalization methods. We take as an example the old saw of the induced
thermal mass of a hot scalar field with a quartic coupling, which we compute to
second order in the coupling constant. We show that the form of the result can
be largely determined by renormalization-group arguments without the explicit
evaluation of Feynman graphs.


title: Global QCD Analysis and the CTEQ Parton Distributions

abstract:
  The CTEQ program for the determination of parton distributions through a
global QCD analysis of data for various hard scattering processes is fully
described. A new set of distributions, CTEQ3, incorporating several new types
of data is reported and compared to the two previous sets of CTEQ
distributions. Comparison with current data is discussed in some detail. The
remaining uncertainties in the parton distributions and methods to further
reduce them are assessed. Comparisons with the results of other global analyses
are also presented.


title: Observations On the Potential Confinement of a Light Fermion

abstract:
  We consider possible dynamical models for a light fermion confined by a
potential field. With the Dirac equation only Lorentz scalar confinement yields
normalizable wavefunctions, while with the ``no pair'' variant of the Dirac
equation only Lorentz vector confinement has normal Regge behaviour.
  A systematic investigation of Regge properties and phenomenological
properties is carried out, including calculations of the Isgur-Wise function.
We point out that the Isgur-Wise function provides a sensitive test of
confinement models. In particular, the slope of the IW function at zero recoil
point is found to be $\xi'(1)\simeq -0.90$ for the Dirac equation with scalar
confinement, and $\xi'(1)\simeq -1.20$ for the no pair equation with vector
confinement. Using heavy-light data alone we argue against scalar confinement.


title:
CP Violation and Strong Phases from Penguins in $\bf B^{\pm}\rightarrow
  PP$ and $\bf B^{\pm}\rightarrow VP$ Decays

abstract:
  We calculate direct CP-violating rate asymmetries in charged $B\to PP$ and
$B\to VP$ decays arising from the interference of amplitudes with different
strong and CKM phases. The perturbative strong phases develop at order
$\alpha_s$ from absorptive parts of one-loop matrix elements of the
next-to-leading logarithm corrected effective Hamiltonian. CPT constraints are
maintained. Based on this model, we find that partial rate asymmetries between
charge conjugate $B^{\pm}$ decays can be as high as 20\% for certain channels
with branching ratios in the $10^{-6}$ range. Because the $c\bar{c}$ threshold
lies so close to the physical momentum scale, the asymmetries depend
sensitively on the model assumptions used to evaluate the imaginary parts of
the matrix elements, in particular, on the internal momentum transfer. The
charge asymmetries of partial rates would provide unambiguous evidence for
direct CP violation.


title: Anomalous Violation of Conservation Laws in Minkowski Space

abstract:
  We consider the evolution of quantum fermi fields in Minkowski gauge field
backgrounds. Our motivation is the study of anomalous fermion number violating
processes. We derive selection rules for fermion scattering amplitudes which
relate the violation of fermionic charge to the change in winding between early
and late times of the vacuum part of the gauge field. We find that the amount
of fermion number violation is always integer, even when the topological charge
of the gauge field is fractional. As an explicit example, we apply our results
to spherically symmetric Minkowski solutions.


title:
Anomalous Violation of Conservation Laws in Minkowski Space:
  Spontaneously Broken Gauge Theories

abstract:
  We extend our previous results on the evolution of quantum fermi fields in
Minkowski gauge field backgrounds to the case of spontaneously broken gauge
theories. We obtain a selection rule which relates the amount of fermion number
violation to the change in Higgs winding number of the configuration. This
selection rule is applicable to any classical solution which dissipates at both
early and late times.


title: Quark Mass Corrections to the Z Boson Decay Rates

abstract:
  The results of perturbative QCD evaluation of the ~m_f^2/M_Z^2 contributions
to the decay rates in Z--->bb and Z--->hadrons for the quark masses m_f << M_Z
are presented. The recent results due to the combination of renormalization
group constraints and the results of several other calculations are
independently confirmed by the direct computation. Some existing confusion in
the literature is clarified. In addition, the calculated O(alpha_s^2)
correction to the correlation function in the axial channel is a necessary
ingredient for the yet uncalculated axial part of the O(alpha_s^3) mass
correction to the Z decay rates. The results can be applied to the \tau
hadronic width.


title: Spin Structure of the Proton

abstract:
  By assuming that there is no significant intrinsic polarization of the gluon,
we have computed the polarized quark contributions to the proton's spin under
SU(3) flavor symmetry breaking for the polarized sea and have performed a
global leading-order QCD fit to obtain the spin-dependent quark distributions,
which could be used as input for analyzing lepton-hadron and hadron-hadron
collisions.


title:
The Intercept of Symmetric Multigluon Configurations in the Variational
  Approach

abstract:
  To calculate the intercept of the multigluon system in a symmetric spatial
configuration a variational method is developed based on a complete system of
one-gluon functions. The method is applied to two- and three- gluon cases to
compare with the known results. The convergence turns out rather slow. Ways to
improve results are discussed.


title: Heavy-Neutrino Effects on tau-Lepton Decays

abstract:
  Minimal extensions of the Standard Model that are motivated by grand unified
theories or superstring models with an E_6 symmetry can naturally predict heavy
neutrinos of Dirac or Majorana nature. Such heavy neutral leptons violate the
de- coupling theorem at the one-loop electroweak order and hence offer a unique
chance for possible lepton-flavour decays of the tau lepton, e.g. tau -> eee or
tau -> mu mu mu, to be seen in LEP experiments. We analyze such decays in
models with three and four generations.


title:
Electric Dipole Moments of Neutron and Electron in Two-Higgs-Doublet
  Model with Maximal $CP$ violation

abstract:
  We study the electric dipole moments(EDM) of the neutron and the electron in
the two-Higgs-doublet model, in the case that $CP$ symmetry is violated
maximally in the neutral Higgs sector. We take account of the Weinberg's
operator $O_{3g}=GG\t G$ as well as the operator $O_{qg}=\bar q\sigma\tilde Gq$
for the neutron, and the Barr-Zee diagrams for the electron. It is found that
the predicted neutron EDM could be considerably reduced by the destructive
contribution of the two Higgs scalars to get the lower value than the
experimental bound. As to the electron EDM, the predicted value is smaller in
one order than the experimental one.


title: Matrix-Element Corrections to Parton Shower Algorithms

abstract:
  We discuss two ways in which parton shower algorithms can be supplemented by
matrix-element corrections to ensure the correct hard limit: by using
complementary phase-space regions, or by modifying the shower itself. In the
former case, existing algorithms are self-consistent only if the total
correction is small. In the latter case, existing algorithms are never
self-consistent, a problem that is particularly severe for angular-ordered
parton shower algorithms. We show how to construct self-consistent algorithms
in both cases. The postscript file for this paper can also be obtained by
anonymous ftp from thep.lu.se in the file pub/Preprints/lu_tp_94_17.ps


title:
Thermalization and pinch singularities in non-equilibrium quantum field
  theory

abstract:
  I argue that, within the Closed-Time-Path formalism, pinch singularities do
not appear in truly out of equilibrium situations.


title: Possible Candidates for SUSY SO(10) Model with an Intermediate Scale

abstract:
  We study the possibility of an intermediate scale existing in supersymmetric
SO(10) grand unified theories: The intermediate scale is demanded to be around
10^{12} GeV so that neutrinos can obtain masses suitable for explaining the
experimental data on the deficit of solar neutrino with
Mikheev-Smirnov-Wolfenstein solution and the existence of hot dark matter. We
show that any Pati-Salam type intermediate symmetries are excluded by requiring
reasonable conditions and only $SU(2)_L\times SU(2)_R \times SU(3)_C\times
U(1)_{B-L}$ is likely to be realized as an intermediate symmetry.


title: Relativistic Effects in S-Wave Quarkonium Decay

abstract:
  The decay widths of S-wave quarkonia ($\etc,\etb\to \gg{~~and~~}
\J,\U\to\ee$) are calculated on the basis of a quasipotential approach. The
nontrivial dependence on relative quark motion of decay amplitude is taken into
consideration via quarkonium wave function. It is shown that relativistic
corrections may be large (10-50 %) and comparable with QCD corrections.


title:
Implications of High Precision Experiments and the CDF Top Quark
  Candidates

abstract:
  We discuss the consequences of recent experimental results from CDF, SLC, LEP
and elsewhere for the Standard Model and for new physics. A global fit to all
indirect precision data yields $m_t = 175 \pm 11^{+17}_{-19}$~GeV,
$\sin^2\theta_{MS} = 0.2317(3)(2)$, and $\alpha_s = 0.127(5)(2)$, where the
central values are for $M_H = 300$ GeV and the second uncertainties are for
$M_H \rightarrow 1000$ GeV (+) and 60 GeV (-). The $m_t$ value is in remarkable
agreement with the value $m_t=174 \pm 16$ GeV suggested by the CDF candidate
events. There is a slight preference for a light Higgs with $M_H < 730$ (880)
GeV at 95\% c.l. if the CDF $m_t$ value is (not) included. The sensitivity is,
however, due almost entirely to the anomalously large observed values for the
$Z \rightarrow b\bar{b}$ width and left-right asymmetry. The value of alpha_s
(from the lineshape) is clean theoretically assuming the Standard Model, but is
sensitive to the presence of new physics contributions to the $Z \rightarrow
b\bar{b}$ vertex. Allowing a vertex correction $\delta_{b\bar{b}}^{\rm new}$
one obtains the significantly lower value alpha_s = 0.111 \pm 0.009, in better
agreement with low energy determinations, and $\delta_{b\bar{b}}^{\rm new} =
0.023 \pm 0.011$. There is now enough data to perform more general fits to
parameters describing new physics effects and to separate these from $m_t$ and
$M_H$. Allowing the parameter $\rho_0$, which describes sources of $SU(2)$
breaking beyond the Standard Model, to be free one finds $\rho_0=1.0012 \pm
0.0017 \pm 0.0017$, remarkably close to unity. One can also separate the new
physics contributions to the oblique parameters $S_{\rm new}$, $T_{\rm new}$
and $U_{\rm new}$, which all take values consistent with zero. The effects of
supersymmetry on the determination of the SM parameters are discussed.


title:
Determination of SU(6) Clebsch-Gordan Coefficients and Baryon Mass and
  Electromagnetic Moment Relations

abstract:
  We compute and tabulate the Clesbsch--Gordan coefficients of the $SU(6)
\supset SU(3) \times SU(2)$ product ${\overline{\bf 56}} \otimes {\bf 56}$,
which are relevant to the nonrelativistic spin-flavor symmetry of the lightest
baryons. Under the assumption that the largest representation in this product,
the ${\bf 2695}$, gives rise to operators in a chiral expansion that produce
numerically small effects, we obtain a set of relations among the masses of the
baryons, as well as among their magnetic dipole and higher multipole moments.
We compare the mass relations to experiment, and find numerical predictions for
the $\Sigma^0$-$\Lambda$ mass mixing parameter and eighteen of the twenty-seven
magnetic moments in the ${\bf 56}$.


title: New strong sector, odd-parity processes, and the Tevatron

abstract:
  The color-octet isosinglet "rho" of a new strong-interaction sector is
readily produced in ppbar collisions. Its odd-parity decay to an "eta" and a
gluon may exceed its decay rate to dijets. At center of mass energies
sufficiently greater than the colored "rho" mass, the odd-parity production of
("omega" + colored "eta") or ("rho" + colored "pion") may be comparable to
ttbar production. Considering that the "omega" has a dominant odd-parity decay
mode, we end up with (Z, W, or gamma) + 4 jet events with two of the jets
containing b or bbar.


title: An Open Universe from Inflation

abstract:
  We present a natural scenario for obtaining an open universe ($\Omega _0<1$)
through inflation. In this scenario, there are two epochs of inflationary
expansion---an epoch of `old inflation,' during which the inflaton field is
stuck in a false vacuum, followed by an epoch of `new inflation,' during which
the inflaton field slowly rolls toward its true minimum. During the first
epoch, inflation solves the smoothness and horizon problems. Then an open
universe (with negative spatial curvature) is created by the nucleation of a
single bubble. In effect $\Omega$ is instantaneously `reset' to zero. During
the subsequent `new' inflation $\Omega$ rises toward unity. The value of
$\Omega$ today is calculable in terms of the parameters of the potential, and
we show that obtaining values significantly different from zero or unity
(though within the range $0<\Omega <1$) does not require significant fine
tuning. We compute the spectrum of density perturbations by evolving the
Bunch-Davies vacuum modes across the bubble wall into its interior.


title: Non-decoupling effects of the Standard Model Higgs boson to one loop

abstract:
  We study the complete non-decoupling effects of the standard model Higgs
boson to one loop. Using effective field theory methods, we integrate out the
Higgs boson and represent its non-decoupling effects by a set of gauge
invariant effective operators of the electroweak chiral Lagrangian. In a
previous work, we analyzed the non-decoupling effects in the two and three
point Green's functions of gauge fields. We complete here the calculation of
the chiral effective operators by analyzing the four point functions. We
discuss in detail the relation between the renormalization of both the standard
model and the effective theory, which is crutial for a correct understanding
and use of the electroweak chiral Lagrangian. Some examples have been chosen to
show the applicability of this effective Lagrangian approach in the calculation
of low energy observables in electroweak theory.


title: Can We Identify a Light Neutralino in B-Factories

abstract:
  If a light gaugino sector exists, then the lightest supersymmetric particle
(LSP) has a chance of being pair-produced in rare B-decays. As a consequence of
neutral flavour violation in most supersymmetric models, such decays can occur
at the tree-level and reinforce the channels $B \longrightarrow K(K^{*}) +
invisible$. We discuss how a study of such decay spectra in B-factories can
help us either identify or exclude a light LSP.


title:
Renormalization Group Improved Radiative Corrections to the
  Supersymmetric Higgs Boson Masses

abstract:
  The one-loop radiative corrections to the Higgs boson potential in the MSSM,
originating from the top quark and squark loops, are summed in the leading log
approximation using the renormalization group. The RG improved effective
potential is minimized and the corrections to the CP-odd and CP-even Higgs
boson masses are calculated. The resulting masses exhibit smoother top mass
dependence than those calculated without RG summation. We have also found that
for preferable values of the top mass the light Higgs mass does not exceed 100
GeV.


title: Heavy Meson Hyperfine Splitting: A Complete $1/m_Q$ Calculation

abstract:
  The hyperfine splittings $\Delta_D=(m_{D^*_s}-m_{D_s})-(m_{D^{*+}}-m_{D^+})$
and $\Delta_B=(m_{B^*_s}-m_{B_s})-(m_{B^{*0}}-m_{B^0})$ are analyzed in the
framework of an effective lagrangian possessing chiral, heavy flavour and spin
symmetries, explicitly broken by a complete set of first order terms. Among
these terms, those responsible for the difference between the couplings $\gis$
and $\gi$ are evaluated in the QCD sum rules approach. Their contribution to
$\Delta_D$ and to $\Delta_B$ appears to quantitatively balance previously
estimated chiral effects nice agreement with the experimental data, solving a
suspected puzzle for heavy quark theory.


title: Nonperturbative Corrections in Resummed Cross Sections

abstract:
  We show that the resummation of large perturbative corrections in QCD leads
to ambiguities in high energy cross sections that are suppressed by powers of
large momentum scales. These ambiguities are caused by infrared renormalons,
which are a general feature of resummed hard-scattering functions in
perturbative QCD, even though these functions are infrared safe order-by-order
in perturbation theory. As in the case of the operator product expansion, the
contributions of infrared renormalons to coefficient functions may be absorbed
into the definition of higher-dimensional operators, which induce
nonperturbative corrections that are power-suppressed at high energies. The
strength of the suppression is determined by the location of the dominant
infrared renormalon, which may be identified explicitly in the resummed series.
In contrast to the operator product expansion, however, the relevant operators
in factorized hadron-hadron scattering and jet cross sections are generally
nonlocal in QCD, although they may be expressed as local operators in an
effective theory for eikonalized quarks. In this context, we verify and
interpret the presence of $1/Q$ corrections to the inclusive Drell-Yan cross
section with $Q$ the pair mass. In a similar manner, we find $\exp(-b^2\ln Q)$
corrections in the impact parameter space of the transverse momentum
distributions of the Drell-Yan process and $e^+e^-$ annihilation. We also show
that the dominant nonperturbative corrections to cone-based jet cross sections
behave as $1/(Q\delta)$, with $\delta$ the opening angle of the jet and $Q$ the
center of mass energy.


title:
Towards a Field Theoretical Description of Multiparticle Production in
  High Energy Collisions

abstract:
  We present an effective field theory of multiparticle correlations based on
analogy with Ginzburg-Landau theory of superconductivity. With the assumption
that the field represents particle density fluctuations, and in the case of
gaussian-type effective action we find that there are no higer-order
correlations, in agreement with the recent observations in high energy
heavy-ion collisions. We predict that three-dimensional two-particle
correlations have Yukawa form. We also present our results for the
two-dimensional and one-dimensional two-particle correlations (i.e. cumulants)
as projections of our theory to lower dimensions.


title: Isospin Considerations in Correlations of Pions and $B$ mesons

abstract:
  The correlations between a $B$ meson and a pion produced nearby in phase
space should respect isospin reflection symmetry $I_3 \to -I_3$. Thus, one
generally expects similar $\pi^+ B^0$ and $\pi^- B^+$ correlations (non-exotic
channels), and similar $\pi^- B^0$ and $\pi^+ B^+$ correlations (exotic
channels). Exceptions include (a) fragmentation processes involving exchange of
quarks with the producing system, (b) misidentification of charged kaons as
charged pions, and (c) effects of decay products of the associated
$\overline{B}$. All of these can affect the apparent signal for correlations of
charged $B$ mesons with charged hadrons. The identification of the flavor of
neutral $B$ mesons through the decay $B^0 \to K^{*0} J/\psi$ requires good
particle identification in order that the decay $K^{*0} \to K^+ \pi^-$ not be
mistaken for $\overline{K}^{*0} \to K^- \pi^+$, in which case the correlations
of neutral $B$ mesons with hadrons can be underestimated.


title: Issues in the Determination of Parton Distribution Functions

abstract:
  The CTEQ and MRS parton distributions involve a substantial number (~30) of
parameters that are fit to a large number (~900) of data. Typically, these
groups produce fits that represent a good fit to the data, but there is no
substantial attempt to determine the errors associated with the fits.
Determination of errors would involve consideration of the experimental
statistical and systematic errors and also the errors in the theoretical
formulas that relate the measured cross sections to parton distributions. We
discuss the principles that would be needed in such an error analysis. These
principles are standard. However, certain aspects of the principles appear
counter-intuitive in the case of a large number of data. Accordingly, we strive
to devote careful attention to the logic behind the methods.


title: The $\Lambda_b\to J/\psi+\Lambda$ Decay Revisited

abstract:
  The $\b$ decay does not receive any nonspectator contributions and hence its
theoretical calculation is relatively clean. Two different methods are employed
for the study of $\b$. In the first method, both $b$ and $s$ quarks are treated
as heavy and leading $1/m_s$ as well as $1/m_b$ corrections are included. The
branching ratio and the asymmetry parameter $\alpha$ are found to be
$(0.7-1.5)\times 10^{-3}$ and $0.18$, respectively. In the second method, only
the $b$ quark is treated as heavy. The prediction of the decay rate is very
sensitive to the choice of the $q^2$ dependence for form factors. We obtain
$\alpha=0.31$ and ${\cal B}(\b) \simeq 1.6\times 10^{-4}$ for dipole $q^2$
behavior as well as $8.2\times 10^{-4}$ for monopole $q^2$ dependence. We
conclude that ${\cal B}(\b)~{\large ^<_{\sim}}~10^{-3}$ and $\alpha$ is of
order $0.20\sim 0.30$ with a positive sign.


title: Tests of flavour independence in heavy quark potential models

abstract:
  We review some rigourous consequences of flavour independence on the spectrum
and properties of hadrons in potential models, with emphasis on hadrons with
two heavy quarks, such as $(b\bar c)$ mesons and $(QQq)$ baryons.


title: Towards the Phenomenology of QCD-Instanton Induced Particle Production

abstract:
  We present a first status report on a broad and systematic study of possible
manifestations of QCD-instantons at HERA. Considerable motivation comes from
the close analogy between instanton-induced $B+L$ violation in electroweak
processes and effects of QCD-instantons in deep inelastic scattering. We
concentrate on the high multiplicity final state structure, reminiscent of an
isotropically decaying ``fireball''. A set of experimental isolation criteria
is proposed. They serve to further enhance the striking event signature without
significantly suppressing the expected rates.


title: Fermion Masses in Superstring Theory

abstract:
  We give a model-independent discussion of fermion masses in four-dimensional
heterotic superstring theories. We discuss the tree level contributions and
quantum corrections, including one-loop threshold effects and masses generated
as a result of non-perturbative supersymmetry breaking. We also point out that
superstring models give rise to a generic $\mu$-term in the effective low
energy Lagrangian.


title:
Atmospheric Neutrino Problem in Maximally-Mixed Three Generations of
  Neutrinos

abstract:
  Motivated by the indication that both the atmospheric and the solar neutrino
puzzles may simultaneously be solved by (vacuum as well as matter-induced
resonant) oscillations of two generations of neutrinos with large mixing, we
have analyzed the data on the atmospheric and solar neutrinos assuming that all
{\it three} neutrinos are maximally mixed. It is shown that the values of $
\Delta m^2 $ obtained from the two-generation analyses are still valid even in
the three-generation scheme, i.e. the two puzzles can be solved simultaneously
if $ \Delta m_{31}^2 \simeq 10^{-2} \, \mathrm{eV}^2 $ for the atmospheric
neutrinos and $ \Delta m_{21}^2 \simeq 10^{-10} \, \mathrm{eV}^2 $ for solar
neutrinos in the maximally mixed three-generation scheme.


title: New Corrections of Order $\alpha^6$ to $s$-Levels of Two-Body Systems

abstract:
  New corrections to the energy of $S$-levels of positronium of order
$m\alpha^6$ which are as large as several hundred kilohertz are obtained. A new
recoil correction of order $\alpha(Z\alpha)^5(m/M)m$ to the Lamb shift in
hydrogen is calculated. This correction turns out to be too small from the
phenomenological point of view.


title: Semileptonic Decays of Heavy Tetraquarks

abstract:
  There exist heavy tetraquark states $QQ \bar q \bar q$ in the heavy quark
limit. These states are stable with respect to strong interactions and hence
must decay weakly. It is shown that the semileptonic decay depends on a single
Isgur--Wise form factor, which can be expressed in term of the Isgur--Wise form
factors which govern the semileptonic decays of the $Qqq$ and $QQq$ baryons.


title: Gauge-Yukawa Unification: Going Beyond GUTs

abstract:
  We discuss the basic idea of the Gauge-Yukawa Unification that is based on
the principle of the reduction of couplings. This method of unification relies
on the search of successful renormalization group invariant relations among
couplings, which do not originate from symmetry principles. The predictive
power of Grand Unified Theories can be increased by this method, predicting for
instance values of the top quark mass consistent with the recent experimental
data. The hope is that this unification attempt might shed further light on the
origin of the Yukawa sector of the standard model.


title: Probing CP in the Higgs Sector

abstract:
  We discuss how one may determine whether some Higgs particle is an eigenstate
of $CP$ or not, and if so, how we may probe whether it is $CP$-odd or
$CP$-even. The idea is applied to Higgs decay where correlations among momenta
of the decay products may yield the desired information. These are correlations
of decay planes defined by the momenta of pairs of particles as well as
correlations between energy differences. In the case that the Higgs particle is
an eigenstate of $CP$, our study includes finite-width effects. The
correlations between energy differences turn out to be a much better probe for
investigating $CP$ properties than the previously suggested angular
correlations, especially for massive Higgs bosons.


title: Bounds on Compositeness from Neutrinoless Double Beta Decay

abstract:
  Assuming the existence of a heavy Majorana neutral particle arising from a
composite model scenario we discuss the constraints imposed by present
experimental limits of half-life neutrinoless double beta decay
$(0\nu\beta\beta ) $ measurements on the coupling of the heavy composite
neutrinos to the gauge bosons. For neutrino masses $M_N = 1 $ TeV we obtain a
rather weak lower bound on the compositeness scale: $\Lambda \ge 0.23 $ TeV.


title:
Oblique corrections and the quadratic approximation in electroweak
  precision testing

abstract:
  This paper is withdrawn. A revised and expanded version of this work is
available as hep-ph/9603323.


title: Factorial Moments of Continuous Order

abstract:
  The normalized factorial moments $F_q$ are continued to noninteger values of
the order $q$, satisfying the condition that the statistical fluctuations
remain filtered out. That is, for Poisson distribution $F_q = 1$ for all $q$.
The continuation procedure is designed with phenomenology and data analysis in
mind. Examples are given to show how $F_q$ can be obtained for positive and
negative values of $q$. With $q$ being continuous, multifractal analysis is
made possible for multiplicity distributions that arise from self-similar
dynamics. A step-by-step procedure of the method is summarized in the
conclusion.


title: The Spin Structure of Nucleons and Deep Inelastic Scatterings

abstract:
  Based on a simple model which is compatible with the idea of the static quark
model and the parton model, the polarized structure functions of proton and
deuteron, two-spin asymmetries of $\pi ^0$ in polarized $pp$ reactions and
inelastic $J/\psi$ productions in polarized lepton-proton collisions are
analyzed. In particular, an important role of polarized gluon distributions is
pointed out.


title: The Shape of Polarized Gluon Distributions

abstract:
  The recent high precision SMC data on polarized $\mu p$ scatterings have
again confirmed that very little of the proton spin is carried by quarks. To
unravel the mystery of the proton spin structure, it is quite important to know
the behavior of the polarized gluon distribution. By using the positivity
condition of distribution functions together with the unpolarized and polarized
experimental data, we restrict the $x$ dependence of the polarized gluon
distribution.


title: Naive nonabelianization and resummation of fermion bubble chains

abstract:
  We propose to extend the Brodsky-Lepage-Mackenzie scale-fixing prescription
by resumming exactly any number of one-loop vacuum polarization insertions into
one-loop diagrams. In this way, one makes maximal use of the information
contained in one-loop perturbative corrections combined with the one-loop
running of the effective coupling. The scale ambiguity at leading order is
converted into an intrinsic uncertainty of perturbative approximations induced
by IR renormalons. Practical implementation of this resummation requires only
knowledge of one-loop radiative corrections with non-vanishing gluon mass. We
find that higher order corrections to the pole mass and the top quark decay
width are dominated by renormalons already in low orders and demonstrate the
impact of eliminating the pole mass on the convergence of the perturbative
series.


title:
Electromagnetic Polarizabilities and Charge Radii of the Nucleons in the
  Diquark-model

abstract:
  The diquark model is used to calculate the electromagnetic polarizabilities
and charge radii of the nucleons for three different potentials. Making the
scalar diquark lower in mass introduces a mixing angle $\theta $ between the
$\left| 56\right\rangle $ and $\left| 70\right\rangle $ states ,which allows an
improvement in value of all 6 properties. Generalizing the Gamov-Teller matrix
and the magnetic moment operator to the diquark model gives constraints on this
mixing. We obtain for the Richardson potential $\theta =23.2^{\circ },$
$\overline{\alpha }_p=7.9_{-0.9}^{+1.0}\times 10^{-4}fm^3,$ $\overline{\alpha
}_n=7.7_{-0.6}^{+0.3}\times 10^{-4}fm^3,$ $\overline{\beta
}_p=5.4_{-0.4}^{+1.6}\times 10^{-4}fm^3,$ $\overline{\beta }%
_n=6.7_{-0.7}^{+1.3}\times 10^{-4}fm^3,$ $\left\langle r^2\right\rangle
_p=0.37_{-0.03}^{+0.02}fm^2,$ $\left\langle r^2\right\rangle
_n=-0.07_{-0.02}^{+0.03}fm^2.$ Additional pion cloud contributions could
improve on all six results.


title: Runaway Quarks

abstract:
  When heavy nuclei collide, a quark-gluon plasma is formed. The plasma is
subject to strong electric field due to the charge of the colliding nuclei. The
electric field can influence the behavior of the quark-gluon plasma. In
particular, we might observe an increased number of quarks moving in the
direction of that field, as we do in the standard electron-ion plasma. In this
paper we show that this phenomenon, called the runaway quarks, does not exist.


title: Chiral Perturbation Theory

abstract:
  An introduction to Chiral Perturbation Theory is given including a discussion
of power counting, the Wess-Zumino term, the values of the coupling constants
and the inclusion of the effects of other resonances.


title: $\sin^2\theta_W(M_Z)$ ~in the MSSM and Unification of Couplings

abstract:
  We calculate ~$\sin^2\theta(M_Z)$ ~in the MSSM in terms of ~ $\alpha_{EM}$,
~$G_F$, ~$m_t$, ~$\tan\beta$ ~and SUSY mass parameters with the same accuracy
as the present calculations of ~$\sin^2\theta(M_Z)$ ~in the SM. We compare the
results with the standard leading logarithmic approximation used for SUSY
threshold corrections and find important differences in the case of light
sparticles. We give approximate formulae connecting coupling constants in the
SM and in the MSSM and comment on process dependence of such formulae. The
obtained values of the MSSM couplings ~$\alpha_i(M_Z)$ ~are used to investigate
gauge coupling unification in the minimal SUSY ~SU(5) ~model. Our
non-logarithmic corrections lower the predicted value of the Higgs triplet
mass. The interplay between the supersymmetric and GUT thresholds in achieving
unification for the coupling constants in the range of the experimentally
acceptable values is quantified.


title: Spin-Flavor Structure of Large N Baryons

abstract:
  The spin-flavor structure of large N baryons is described in the 1/N
expansion of QCD using quark operators. The complete set of quark operator
identities is obtained, and used to derive an operator reduction rule which
simplifies the 1/N expansion. The operator reduction rule is applied to the
axial currents, masses, magnetic moments and hyperon non-leptonic decay
amplitudes in the $SU(3)$ limit, to first order in $SU(3)$ breaking, and
without assuming $SU(3)$ symmetry. The connection between the Skyrme and quark
representations is discussed. An explicit formula is given for the quark model
operators in terms of the Skyrme model operators to all orders in $1/\N$ for
the two flavor case.


title: Tau as a Probe for New Physics

abstract:
  The usage of polarimetry and spin-correlation tests to determine the {\em
complete Lorentz structure} of the tau lepton's charged and neutral-current
couplings is reviewed. The emphasis is on tests for ``something'' in a $(V-A) +
$ ``something'' structure in ${J^{Charged}}_{Lepton}$ current, so as to bound
the scales $\Lambda$ for ``new physics" such as arising from tau weak
magnetism, weak electricity, and/or second-class currents. Tests for $T$ and
for $CP$ violation are discussed.


title: Topology and Confinement In Light-Front QCD

abstract:
  In 1+1 dimensional compact QCD the zero modes of $A^+$ give the theory a non-
trivial topological structure. We examine the effects of these topological
structures on the confining infrared structure of the theory. We show that the
ground state wavefunction of the topological excitation smears the infrared
behavior sufficiently to eliminate confinement for some matter currents. We
review the work of Franke et.al. which shows that the zero modes of$A^+$ in
$QCD_{3+1}$ give rise to instantons. The relation of zero modes of$A^+$.Invited
talk at the workshop on "Theory of Hadrons ond Light-Front QCD" at Polona
Zgorzelisko, Poland August 15-25 1994


title: Comparison of Discovery Limits for Extra Z Bosons at Future Colliders

abstract:
  We study and compare the discovery potential for heavy neutral gauge bosons
($Z'$) at various $e^+e^-$ and $p\stackrel{(-)}{p}$ colliders that are planned
or have been proposed. Typical discovery limits are for the TEVATRON $\sim 1$
TeV, DI-TEVATRON $\sim 2$ TeV, LHC $\sim 4$ TeV, LSGNA (a 60 TeV $pp$ collider)
$\sim 13$ TeV while the $e^+e^-$ discovery limits are $2-10\times \sqrt{s}$
with the large variation reflecting the model dependence of the limits. While
both types of colliders have comparable discovery limits the hadron colliders
are generally less dependent on the specific $Z'$ model and provide more robust
limits since the signal has little background. In contrast, discovery limits
for $e^+e^-$ limits are more model dependent and because they are based on
indirect inferences of deviations from standard model predictions, they are
more sensitive to systematic errors.


title:
Dyson-Schwinger equations and their application to nonperturbative field
  theory

abstract:
  Two examples of recent progress in applications of the Dyson-Schwinger
equation (DSE) formalism are presented: (1) Strong coupling quantum
electrodynamics in 4 dimensions (QED$_4$) is an often studied model, which is
of interest both in its own right and as an abelian model of quantum
chromodynamics (QCD). We present results from a study of subtractive
renormalization of the fermion propagator Dyson-Schwinger equation (DSE) in
massive strong-coupling quenched QED$_4$. The procedure is straightforward to
implement and numerically stable. (2) The Bethe-Salpeter equation (BSE) with a
class of non-ladder scattering kernels is solved in {\it Minkowski space} in
terms of the perturbation theory integral representation (PTIR). We consider a
bound state of two spinless particles with the formal expression of the full
scattering kernel in a $\phi^2\sigma$ scalar model. We derive an integral
equation for the weight function with a real kernel. We recover as a check
results for the massive scalar ladder approximation.


title:
Radiative Symmetry Breaking in a Supersymmetric Model with an Extra
  $U(1)$

abstract:
  Radiative symmetry breaking is studied in a superstring-inspired
supersymmetric model which is extended with a low energy extra $U(1)$ symmetry.
In this model the $\mu$-problem is radiatively solved in an automatic way. The
right-handed neutrino can be heavy and the seesaw mechanism will produce the
small neutrino mass which makes the MSW solution applicable to the solar
neutrino problem. We search a parameter region which has the favorable feature
for the radiative symmetry breaking at the weak scale. Rather wide parameter
region is found to be allowed. The upper bound of the extra $Z$ boson mass is
estimated as $M_{Z_2} \le 2000$~GeV for a top mass range $ 150~{\rm GeV} \le
m_t \le 190~{\rm GeV}$. Some phenomenological features of the extra $Z$ boson
are also presented.


title: On the lagrangian of N=1, D=10 dual supergravity

abstract:
  It is shown how one can construct the lagrangian of dual supergravity by
means of the equations of motion derived from the superspace approach.


title:
Infrared Fixed Points and Fixed Lines in the Top-Bottom-Tau Sector in
  Supersymmetric Grand Unification

abstract:
  The two-loop ``top-down'' renormalization group flow for the top, bottom and
tau Yukawa couplings is explored in the framework of supersymmetric grand
unification; reproduction of the physical bottom and tau masses is required.
Instead of following the recent trend of implementing exact Yukawa coupling
unification i) a search for infrared (IR) fixed lines and fixed points in the
m(top)-tan(beta) plane is performed and ii) the extent to which these imply
approximate Yukawa unification is determined. Two IR fixed lines, intersecting
in an IR fixed point, are located. The more attractive fixed line has a branch
of almost constant top mass, 168-180 GeV, close to the experimental value, for
the large interval 2.5<tan(beta)<55; it realizes tau-bottom Yukawa unification
at MGUT approximately. The fixed point at m(top)= 170 GeV, tan(beta)=55
implements approximate top-bottom Yukawa unification at all scales. The fixed
point and lines are distinct from the much quoted effective IR fixed point
m(top)=O(200)GeV sin(beta).


title:
Proton-ring and Electron-linac Collider (PRELC) as a (first)
  TeV-rangeelectron-proton or photon-proton collider

abstract:
  The use of the existing proton storage rings combined with electron linear
accelerator as a ring-linac type electron-proton or photon-proton collider is
investigated. The total CM-energy of Proton-ring and Electron-linac Collider
(PRELC) is in the range of 1.0 TeV. The most important physical issues are
listed and the most critical machine aspects of the PRELC are studied. It is
shown that the luminosities in the range of $10^{31}$ to $10^{32}$ could be
achieved. The PRELC could be used simultaneously with the $e^+e^-$-collider if
the refocused electron beam could be used as the electron beam for the PRELC.


title: Tests of gauge boson couplings in polarized $e^-\gamma$ collisions

abstract:
  Single $W$-boson production in $e^-\gamma$ collisions with polarized beams is
investigated. Helicity amplitudes for general couplings are derived and their
properties are discussed. The results are applied to the Standard Model (SM)
and the left-right model. In the framework of SM the updated estimates of the
measurement precision of photon anomalous coupling parameters $ \kappa,$ $
\lambda$ at the NLC with $ \sqrt{s_{ ee }}=500$GeV are obtained. The production
of right-handed gauge bosons $ W^-_{ 2 }$ in these collisions is also analysed.


title: Quantum Field Theory of Bose-Einstein Correlations

abstract:
  A Quantum Field Theory formulation of Bose-Einstein Correlations is given. It
contains as a special case the classical current approach. It is shown that the
particle-antiparticle correlations are a general feature of Bose-Einstein
Correlations and not an artifact of a certain approximation. Relations are
provided through which the quantum corrections to the classical current
approach can be determined experimentally.


title:
Photon Structure Functions: Target Photon Mass Effects and QCD
  Corrections

abstract:
  We present a systematic analysis of the processes $e^+ ~e^- \rightarrow e^+
~e^- X$ to study the polarised and unpolarised photon structure functions. The
effect of target photon mass, which manifests itself as new singly polarised
structure functions is studied. The physical interpretation of these structure
functions in terms of hadronic components is given using the free field
analysis. Assuming factorisation of the photon structure tensor, the relevant
QCD corrections to the various structure functions are evaluated. The effect of
the target photon mass and QCD corrections on the unpolarised and polarised
cross sections are also studied.


title: Direct Instanton Effects in Current-Current Correlators

abstract:
  We compute the effect of small-size instantons on the coefficient function of
the chiral condensate in the operator product expansion of current-current
correlators. Furthermore, we also compute the instanton corrections associated
with four-quark and six-quark operators in the factorization approximation. We
discuss the phenomenological implications of our result.


title: Grand Unification and the Standard Model

abstract:
  The current status of gauge unification is surveyed both in the standard
model and its minimal supersymmetric extension. Implications for proton decay,
Yukawa unification, and the Higgs mass are described.


title: Light-Gluino Production at LEP

abstract:
  If gluinos are light, they will be produced in electron-positron annihilation
at LEP, not only by radiation in pairs off quarks and antiquarks, but also
without accompanying quark and antiquark jets. We here discuss the latter
process, pair production of gluinos, in a model with soft supersymmetry
breaking, allowing for mixing between the squarks. In much of the parameter
space of the Minimal Supersymmetric Model (MSSM) the cross section corresponds
to a $Z$ branching ratio above $10^{-5}$, even up to $10^{-4}$. A
non-observation of gluinos at this level restricts the allowed MSSM parameter
space.


title:
Natural R Parity Conservation with Horizontal Symmetries. a Four
  Generation Model

abstract:
  In most supersymmetric models the stability of the proton is ensured by
invoking R-parity. A necessary ingredient to enforce R-parity is the
possibility of distinguishing the lepton superfields from the Higgs ones. This
is generally achieved either by assuming different charges under some matter
parity, or by assigning the superfields to different representations of a
unified gauge group. We want to put forward the idea that the replica of the
fermion generations, which constitute an intrinsic difference between the
fermions and the Higgs superfields, can give a clue to understand R-parity as
an accidental symmetry. More ambitiously, we suggest a possible relation
between proton stability and the actual number of fermion generations. We carry
out our investigation in the framework of non-Abelian horizontal gauge
symmetries. We identify $SU(4)_H$ as the only acceptable horizontal gauge group
whichcan naturally ensure the absence of R parity violating operators, without
conflicting with other theoretical and phenomenological constraints. We analyze
a version of the supersymmetric standard model equipped with a gauged
horizontal $SU(4)_H$, in which R-parity is accidental. The model predicts four
families of fermions, it allows for the dynamical generation of a realistic
hierarchy of fermion masseswithout any ad hoc choice of small Yukawa couplings,
it ensures in a natural way the heaviness of all the fourth family fermions
(including the neutrino) and it predicts a {\it lower} limit for the
$\tau$-neutrino mass of a few eV. The scale of the breaking of the horizontal
symmetry can be constrained rather precisely in a narrow window around $\sim
10^{11}$ GeV. Some interesting astrophysical and cosmological implications of
the model are addressed as well.


title:
Properties of an equilibrium hadron gas subjected to the adiabatic
  longitudinal expansion

abstract:
  We consider an ideal gas of massive hadrons in thermal and chemical
equilibrium. The gas expands longitudinally in an adiabatic way. This evolution
for a baryonless gas reduces to a hydrodynamic expansion. Cooling process is
parametrized by the sound velocity. The sound velocity is temperature dependent
and is strongly influenced by hadron mass spectrum.


title: Finite Energy Instantons in the O(3) Non-Linear Sigma Model

abstract:
  We consider winding number transitions in the two dimensional O(3) non-linear
sigma model, modified by a suitable conformal symmetry breaking term. We
discuss the general properties of the relevant instanton solutions which
dominate the transition amplitudes at finite energy, and find the solutions
numerically. The Euclidean period of the solution increases with energy,
contrary to the behavior found in the abelian Higgs model or simple one
dimensional systems. This indicates that there is a sharp crossover from
instanton dominated tunneling to sphaleron dominated thermal activation at a
certain critical temperature in this model. We argue that the electroweak
theory in four dimensions should exhibit a similar behavior.


title:
Gauge Dependence of the High-Temperature 2-Loop Effective Potential for
  the Higgs Field

abstract:
  The high-temperature limit of the 2-loop effective potential for the Higgs
field is calculated from an effective 3d theory, in a general covariant gauge.
It is shown explicitly that a gauge-independent result can be extracted for the
equation of state from the gauge-dependent effective potential. The convergence
of perturbation theory is estimated in the broken phase, utilizing the gauge
dependence of the effective potential.


title: Generalized Chiral Perturbation Theory

abstract:
  The Generalized Chiral Perturbation Theory enlarges the framework of the
standard $\chi$PT, relaxing certain assumptions which do not necessarily follow
from QCD or from experiment, and which are crucial for the usual formulation of
the low energy expansion. In this way, experimental tests of the foundations of
the standard $\chi$PT become possible. Emphasis is put on physical aspects
rather than on formal developements of G$\chi$PT.


title:
Anomalies in Quantum Field Theory: Dispersion Relations and Differential
  Geometry

abstract:
  We present two different aspects of the anomalies in quantum field theory.
One is the dispersion relation aspect, the other is differential geometry where
we derive the Stora--Zumino chain of descent equations.


title: Light thresholds in Grand Unified Theories

abstract:
  In a generic Grand Unified Theory with a relatively small dispersion of the
spectrum around the $Z$-boson and the unification masses, a connection is
established, exact at one loop level, between $M_Z$, $G_{\rm F}$, $\alpha(M_Z)$
and the strong coupling constant $\alpha_3(M_Z)$. At this level of precision,
this avoids the logical and phenomenological inconsistency of predicting
$\alpha_3(M_Z)$ by means of the electroweak couplings as extracted from the
data in the Standard Model rather than in the complete theory. Attention is
paid to the independence of the physical results from regularization and/or
renormalization schemes. As a particularly relevant example, the analysis is
specialized to the case of the Minimal Supersymmetric Standard Model, with
emphasis on light charginos and neutralinos.


title: Possible Light U(1) Gauge Boson Coupled to Baryon Number

abstract:
  We discuss the phenomenology of a light U(1) gauge boson, $\gamma_B$, that
couples only to baryon number. We assume that the new U(1) gauge symmetry is
spontaneously broken and that the $\gamma_B$ mass is smaller than $m_Z$.
Nevertheless, we show that the model survives the current experimental
constraints. In addition, we argue that evidence for the existence of such a
particle could be hidden in existing LEP and Tevatron data. We determine the
allowed regions of the $m_B$-$\alpha_B$ plane, where $m_B$ is the $\gamma_B$
mass, and where $4 \pi \alpha_B$ is the squared gauge coupling. We point out
that in some parts of the allowed parameter space our model can account for
rapidity gap events in proton-antiproton scattering seen at the Fermilab
Tevatron.


title: The Effective Use of Precision Electroweak Measurements

abstract:
  Several reasonably model-independent formulations of the implications of new
physics for precision electroweak measurements have been developed over the
past years, most notably by Peskin and Takeuchi, and by Altarelli \etal. These
formulations work by identifying a small, but useful, set of parameters through
which new physics often enters into well-measured physical observables. For the
theories to which such an analysis applies, this approach greatly streamlines
the confrontation with the data. Since the experimentally-allowed range for
these parameters has been determined from global fits to the data, theorists
need only compute their predictions for these parameters to constrain their
models. These methods are summarized here, together with several recent
generalizations which permit applications to wider classes of new physics, and
which include the original approaches as special cases.


title: A Vector-like Extension of the Standard Model

abstract:
  A vector-like extension of the standard model for heavier quarks and leptons
with $SU(2)\times U(1)$ gauge symmetry and only one Higgs doublet is examined.
This scheme incorporates infinitely many fermions and avoids the appearance of
a strongly interacting sector. The model is perturbatively well controllable,
and constraints such as $b\rightarrow s\gamma$ and GIM suppression in general
are naturally satisfied if the on-set of heavier fermion mass scale is chosen
at a few TeV. In this scheme, the physical Higgs particle generally mediates
leptonic as well as quark flavor-changing processes at a rate below the present
experimental limit. Vector-like models, if suitably defined, provide a viable
and interesting scheme for physics beyond 1 TeV.


title: The $\pi\pi$ Amplitude in Generalized Chiral Perturbation Theory

abstract:
  The $\pi\pi$ interaction is studied at one loop order in the framework of
Generalized Chiral Perturbation theory


title:
The Large Quark Mass Expansion of Gamma (Z^0 -> hadrons) and Gamma(tau^-
  -> nu_tau + hadrons) in the Order alpha_s^3

abstract:
  We present the analytical $\alpha_{s}^3$ correction to the $Z^{0}$ decay rate
into hadrons. We calculate this correction up to (and including) terms of the
order $(m_Z^2/m_{top}^2)^3$ in the large top quark mass expansion. We rely on
the technique of the large mass expansion of individual Feynman diagrams and
treat its application in detail. We convert the obtained results of six flavour
QCD to the results in the effective theory with five active flavours, checking
the decoupling relation of the QCD coupling constant. We also derive the large
charm quark mass expansion of the semihadronic $\tau$ lepton decay rate in the
$\alpha_{s}^3$ approximation.


title: A Catching Trap for All Antiproton Seasons

abstract:
  We describe the origin, development, and status of the Los Alamos antiproton
catching trap. Originally designed for the antiproton gravity experiment, it
now is clear that this device can be a source of low-energy antiprotons for a
wide range of physics, both on site, at CERN, and also off site.


title: Probing Anomalous Gauge Boson Couplings at LEP

abstract:
  We bound anomalous gauge boson couplings using LEP data for the $Z\rightarrow
{\overline f} f$ partial widths. We use an effective field theory formalism to
compute the one-loop corrections resulting from non-standard model three and
four gauge boson vertices. We find that measurements at LEP constrain the three
gauge boson couplings at a level comparable to that obtainable at LEPII.


title: Massive Schwinger Model for Small Fermion Mass

abstract:
  We examine QED$_{1+1}$ (the massive Schwinger model) to extend existing
perturbation results in $m_f/m_b$, and compare our results with lattice and
DLCQ calculations. (Based on a talk presented by J.P. Vary at ``Theory of
Hadrons and Light-Front QCD'', Polona Zgorzelisko, Poland, August 1994.)


title: Heavy Quark Theory

abstract:
  Recent progress in the theory of hadrons containing a single heavy quark is
reviewed. Particular attention is paid to those aspects that bear on the
determination of the magnitudes of the Cabibbo--Kobayashi--Maskawa matrix
elements $V_{cb}$ and $V_{ub}$.}


title: QCD sum rules for $\Delta$ isobar in nuclear matter

abstract:
  The self-energies of $\Delta$ isobar propagating in nuclear matter are
calculated using the finite-density QCD sum-rule methods. The calculations show
that the Lorentz vector self-energy for the $\Delta$ is significantly smaller
than the nucleon vector self-energy. The magnitude of the $\Delta$ scalar
self-energy is larger than the corresponding value for the nucleon, which
suggests a strong attractive net self-energy for the $\Delta$; however, the
prediction for the scalar self-energy is very sensitive to the density
dependence of certain in-medium four-quark condensate. Phenomenological
implications for the couplings of the $\Delta$ to the nuclear scalar and vector
fields are briefly discussed.


title:
Analytic Structure of the Quark Propagator in a Model with an infrared
  vanishing Gluon Propagator

abstract:
  The Dyson-Schwinger equation for the quark self energy is solved in rainbow
approximation using an infrared (IR) vanishing gluon propagator that introduces
an IR mass scale $b$. There exists a $b$ dependent critical coupling indicating
the spontaneous breakdown of chiral symmetry. If one chooses realistic QCD
coupling constants the strength and the scale of spontaneous chiral symmetry
breaking decouple from the IR scale for small $b$ while for large $b$ no
dynamical chiral symmetry breaking occurs. At timelike momenta the quark
propagator possesses a pole, at least for a large range of the parameter $b$.
Therefore it is suggestive that quarks are not confined in this model for all
values of $b$. Furthermore, we argue that the quark propagator is analytic
within the whole complex momentum plane except on the timelike axis. Hence the
na\"{\i}ve Wick rotation is allowed.


title: Reanalysis of hyperon beta decay data on $F/D$

abstract:
  We reanalyse hyperon beta decay data to extract the corresponding F and D
values. We show that flavour symmetry breaking effects lead naturally to a
reduction of the $F/D$ ratio. For proton and neutron our analyses suggests $F/D
= 0.49 \pm 0.08$ instead of $F/D = 0.575 \pm 0.016$ which is generally used to
analyse the spin data. Our smaller $F/D$ value allows to fullfil the
Ellis--Jaffe sum rule implying an unpolarized $s\bar s$-sea.


title: Probing the Higgs mechanism via $\gamma\gamma\to W^+W^-$

abstract:
  We investigate the sensitivity of the reaction $\gamma\gamma\to W^+W^-$ to
the Higgs sector based on the complete one-loop corrections in the minimal
Standard Model and the gauged non-linear $\sigma$-model. While this sensitivity
is very strong for the suppressed cross-section of equally polarized photons
and longitudinal W bosons, it is only marginal for the dominant mode of
transverse polarizations. The corrections within the $\sigma$-model turn out to
be UV-finite in accordance with the absence of $\log\MH$ terms in the Standard
Model with a heavy Higgs boson.


title: Effective Chiral Lagrangians with an SU(3)-Broken Vector-Meson Sector

abstract:
  The accuracy of effective chiral lagrangians including vector-mesons as
(hidden symmetry) gauge fields is shown to be improved by taking into account
SU(3)-breaking in the vector-meson sector. The masses, $M_V$, and couplings to
the photon field and pseudoscalar pairs, $f_{V\gamma}$ and $g_{VPP}$, are all
consistently described in terms of two parameters, which also fit the values
for the pseudoscalar decay-constants, $f_P$, and charge radii, $<r^2_P>$. The
description of the latter is further improved when working in the context of
chiral perturbation theory.


title: Past-Future Interference in $\Phi$-Decays into Entangled Kaon Pairs

abstract:
  Quantum interference effects between past and future events (neutral kaon
transitions, including CP violating decays) are discussed for entangled kaon
pairs produced through $\phi \to K^0 \bar{K^0}$ in $\phi$-factories.
Contrasting with the exciting conclusions of other recent analyses, we predict
the inexistence of such an observable effect.


title: Standard Model predictions for weak decays of $\eta$ mesons

abstract:
  The branching ratios of weak decays of $\eta$ mesons are estimated in the
framework of the Standard Model. To observe such decays, $\eta$ meson sources
with $N_{\eta} > 10^{13}$ per year are needed.


title: Nucleosynthesis and the Time Dependence of Fundamental Couplings

abstract:
  We consider the effects of the time dependence of couplings due to their
dependence on a dilaton field, as occurs in superstring theory, as well as in
gravity theories of the Jordan-Brans-Dicke type. Because the scale parameters
of couplings set by dimensional transmutation depend exponentially on the
dilaton vev, we may obtain stringent limits on the shift of the dilaton from
the requirement that the induced shift in the couplings not vitiate the
successful calculations of element abundances for big-bang nucleosynthesis.
These limits can be substantially stronger than those obtained directly from
the dilaton-induced change in the gravitational coupling.


title: Electric dipole moments as a test of supersymmetric unification

abstract:
  In a class of supersymmetric grand unified theories, including those based on
the gauge group $SO(10)$, there are new contributions to the electric dipole
moments of the neutron and electron, which arise as a heavy top quark effect.
These contributions arise from CKM-like phases, not from phases of the
supersymmetry breaking operators, and can be reliably computed in terms of the
parameters of the weak scale supersymmetric theory. For the expected ranges of
these parameters, the electric dipole moments of the neutron and the electron
are predicted to be close to present experimental limits.


title: Almost Degenerate Neutrinos with Maximal Mixing

abstract:
  If the upper limit on the effective (Majorana) neutrino mass from
neutrinoless double beta decay experiments is confirmed to be much less than an
electron-volt, then one way to reconcile it with the degenerate neutrino mass
pattern suggested recently to explain the observed deficit of solar and
atmospheric neutrinos as well as neutrinos as HDM is to postulate that there be
maximal mixing among the three light (or two) neutrinos. This suggestion is
advanced in this paper and is analysed.


title: An Introduction To The Theory Of Heavy Mesons And Baryons

abstract:
  Introductory lectures (delivered at TASI, June 1994) on heavy quarks and
heavy quark effective field theory. Applications to inclusive semileptonic
decays and to interactions with light mesons are covered in detail.


title: Squark and Slepton Mass Relations in Grand Unified Theories

abstract:
  In the minimal supersymmetric standard model, assuming universal scalar
masses at large energies, there are four intragenerational relations between
the masses of the squarks and sleptons for each light generation. In this paper
we study the scalar mass relations which follow only from the assumption that
at large energies there is a grand unified theory which leads to a significant
prediction of the weak mixing angle. Two new intragenerational mass relations
for each of the light generations are derived. In addition, a third mass
relation is found which relates the Higgs masses, the masses of the third
generation scalars , and the masses of the scalars of the lighter generations.
Verification of a fourth mass relation, involvingonly the charged slepton
masses, provides a signal for SO(10) unification.


title: Probing Anomalous Quartic Vector Boson Couplings in $e^-e^-$ Collisions

abstract:
  We study the incidence of genuine quartic vector boson couplings in the
reactions e-e- -> e-e-ZZ, e-\nu ZW, \nu\nu WW. We find that a linear collider
operated in the e-e- mode will provide bounds on these couplings which are
competitive with those to be obtained in the e+e- mode.


title: Muon decays with lepton--number violation via vector leptoquark

abstract:
  The decays $\mu \rightarrow e \gamma$, $\mu \rightarrow e \gamma \gamma$, and
$\mu \rightarrow e e \bar e$ are analysed in the framework of the Pati-Salam
type quark-lepton symmetry $SU(4)_V \otimes SU(2)_L \otimes G_R$ where the
effects of mixing in the quark-lepton currents are taken into account. It is
shown that the $\mu \rightarrow e \gamma \gamma$ and $\mu \rightarrow e e \bar
e$ decays via the vector leptoquark have not a GIM--type suppression, while the
$\mu \rightarrow e \gamma$ decay has. So, the specific hierarchy of the decay
probabilities could take place $\Gamma(\mu \rightarrow e e \bar e) \gg
\Gamma(\mu \rightarrow e \gamma \gamma) \gg \Gamma(\mu \rightarrow e \gamma)$.
The existing bounds on the vector leptoquark mass and on the mixing matrix
elements, based on the data for the $\mu e$ conversion in nuclei and for the
ratio of the $K_{e 2}$ and $K_{\mu 2}$ decays allow to set the upper limits on
the branching ratios at a level of $10^{-18}$ for the $\mu \rightarrow e \gamma
\gamma$ decay and at a level of $10^{-15}$ for the $\mu \rightarrow e e \bar e$
decay.


title: The Baryon Spectrum and Chiral Dynamics

abstract:
  The fine structure of the low energy part of the nucleon and strange hyperon
spectra, which are formed of single states without parity doublets, may be
understood in terms of an $SU(3)$ flavor-symmetric quark-quark interaction that
describes chiral pseudoscalar boson exchange. The model predicts the fine
structure splittings within 10-30\% of their empirical values and provides an
explanation of the reversed ordering of the lowest positive and negative parity
resonances in the nucleon and the $\Lambda$ hyperon spectra.


title:
The Vertex Corrections in Technicolor Model without Exact Custodial
  Symmetry

abstract:
  We discuss the effects of isospin breaking which appear in the vertex
corrections for $Zb \bar{b}$, $Z\tau^+\tau^-$ and $W\nu\tau$ in a one-family
technicolor model without exact custodial symmetry. By means of the effective
lagrangian approach we compute the vertex corrections for $Zb\bar{b}$,
$Z\tau\tau$ and $W\tau\nu$ taking account of the contributions from
technivectormesons. If the isospin symmetry in technilepton sector is not
exact, technivectormesons contribute to the vertex correction for $Z\tau\tau$
but such contributions to the correction for $W\tau\nu$ are absent. If the
difference is measured, it is the evidence of the isospin breaking.


title: The march towards no-scale supergravity

abstract:
  The different steps that led us to the discovery of {\em no-scale
supergravity} are discussed from a very personal point of view. No-scale
supergravity has been heralded as the most promising effective theory that
describes physics below the Planck scale. In its string-derived form it holds
the potential for a Dynamical Determination Of Everything (DDOE). (Invited talk
presented at the International Conference on: ``The History of Original Ideas
and Basic Discoveries in Particle Physics", Erice, Italy, 29 July - 4 August
1994.)


title: Radiative corrections to $b\to c\tau\bat\nu_\tau$

abstract:
  Analytical calculation is presented of the QCD radiative corrections to the
rate of the process $b\to c\tau\bar\nu_\tau$ and to the $\tau$ lepton
longitudinal polarization in $\tau\bar\nu_\tau$ rest frame. The results are
given in the form of one dimensional infrared finite integrals over the
invariant mass of the leptons. We argue that this form may be optimal for
phenomelogical applications due to a possible breakdown of semilocal
hadron-parton duality in decays of heavy flavours.


title: Wave Function Properties in a High Energy Process

abstract:
  A model example is given of how properties of the hadronic light-cone wave
function are revealed in a particular high energy process. The meson wave
function is derived in scalar quark QCD. We apply it to compute the form of the
cross section for lossless diffractive jet-production, an upcoming possiblity
at HERA.


title: Latest Developments on the Bess Model

abstract:
  The idea of a strongly interacting sector as responsible for the electroweak
symmetry breaking is tested through an effective lagrangian description, called
the BESS model, constructed on the standing point of custodial symmetry and
gauge invariance, without specifing any dynamical scheme.


title: Light Quark Masses from QCD

abstract:
  We study the value of the light quark masses combination $m_u+m_d$ in QCD
using both Finite Energy Sum Rules and Laplace Sum Rules. We have performed a
detailed analysis of both the perturbative QCD and the hadronic parametrization
inputs needed in these Sum Rules. As main result, we obtain $m_u\left(1~{\rm
GeV}^2\right) + m_d \left(1~{\rm GeV}^2\right) = \left(12\pm2.5\right)~{\rm
MeV}$ for the running $\overline{MS}$ masses.


title: Nonleptonic weak decays of charmed mesons

abstract:
  A previous analysis of two-body Cabibbo allowed nonleptonic decays of $D^0$
mesons and of Cabibbo allowed and first-forbidden decays of $D^+$ and $D_s^+$
has been adjourned using more recent experimental data and extended to the
Cabibbo forbidden decays of $D^0$. Annihilation and W-exchange contributions as
well as final state interaction effects (assumed to be dominated by nearby
resonances) have been included and are in fact crucial to obtain a reasonable
agreement with the experimental data, which show large flavour SU(3)
violations. New fitting parameters are necessary to describe rescattering
effects for Cabibbo forbidden $D^0$ decays, given the lack of experimental
informations on isoscalar resonances. We keep their number to a minimum - three
- using phenomenologically based considerations. We also discuss CP violating
asymmetries.


title: Neutral pion photoproduction off nucleons revisited

abstract:
  We investigate threshold pion photoproduction in the framework of heavy
baryon chiral perturbation theory. We give the expansion of the electric dipole
amplitude $E_{0+}$ to three orders in $\mu$, the ratio of the pion to nucleon
mass, and show that it is slowly converging. We argue that this observable is
not a good testing ground for the chiral dynamics of QCD. In contrast, we
exhibit new and fastly converging low--energy theorems in the P--waves which
should be used to constrain the data analysis. We also discuss the importance
of polarization observables to accurately pin down certain multipoles and give
predictions for the reaction $\gamma n \to \pi^0 n$.


title: Jarlskog-like invariants for theories with scalars and fermions

abstract:
  Within the framework of theories where both scalars and fermions are present,
we develop a systematic prescription for the construction of CP-violating
quantities that are invariant under basis transformations of those matter
fields. In theories with Spontaneous Symmetry Breaking, the analysis involves
the vevs' transformation properties under a scalar basis change, with a
considerable simplification of the study of CP violation in the scalar sector.
These techniques are then applied in detail to the two Higgs-doublet model with
quarks. It is shown that there are new invariants involving scalar-fermion
interactions, besides those already derived in previous analyses for the
fermion-gauge and scalar-gauge sectors.


title: The tau weak-magnetic dipole moment

abstract:
  We calculate the prediction for the anomalous weak-magnetic form factor of
the tau lepton at $q^2=M_Z^2$ within the Standard Model. With all particles
on-shell, this is a electroweak gauge invariant quantity. Its value is
$a_\tau^w (M_Z^2)= - \;(2.10 + 0.61\, i) \times 10^{-6}$. We show that the
transverse and normal components of the single-tau polarization of tau pairs
produced at $e^+e^-$ unpolarized collisions are sensitive to the real and
absorptive parts of the anomalous weak-magnetic dipole moment of the tau. The
sensitivity one can achieve at LEP in the measurement of this dipole moment is
discussed.


title: Natural $\mu$-term with Peccei-Quinn Symmetry

abstract:
  The generalized Higgs mass term $NH_1H_2$ of the supersymmetric standard
model is used to implement the Peccei-Quinn Symmetry to solve the strong-CP
problem. Then supersymmetry breaking can generate the Higgs mass parameter
$\mu$ of order $m_{3/2}$ through soft-breaking parameters. This kind of
extension contains extra light fields of the axion supermultiplet whose
dominant coupling may come from the supersymmetric axion-Higgs-Higgs coupling.
We present a working example and discuss the cosmological implications of the
model.


title: The Bess Model at Future Colliders

abstract:
  The BESS model consists of an effective lagrangian parametrization with
dynamical symmetry breaking, describing scalar, vector and axial-vector bound
states in a rather general framework. After a brief description of the model
and its generalizations, predictions for physics at future accelerators are
given both for LHC and e+e- machines. Contribution to the proceedings of the
First Arctic Workshop on Future Physics and Accelerators, Saariselk\"a,
Finland, August 1994.


title: ${1\over m_b}$ and ${1\over m_t}$ Expansion of the Weak Mixing Matrix

abstract:
  We perform a $1/m_b$ and $1/m_t$ expansion of the Cabibbo-Kobayashi- Maskawa
mixing matrix. Data suggest that the dominant parts of the Yukawa couplings are
factorizable into sets of numbers $\vert r>$, $\vert s>$, and $\vert s'>$,
associated, respectively, with the left-handed doublets, the right-handed up
singlets, and the right- handed down singlets. The first order expansion is
consistent with Wolfenstein parameterization, which is an expansion in $sin
\theta _c$ to third order. The mixing matrix elements in the present approach
are partitioned into factors determined by the relative orientations of $\vert
r>$, $\vert s>$, and $\vert s'>$ and the dynamics provided by the subdominant
mass matrices. A short discussion is given of some experimental support and a
generalized Fritzsch model is used to contrast our approach.


title: The Relevant Scale Parameter in the High Temperature Phase of QCD

abstract:
  We introduce the running coupling constant of QCD in the high temperature
phase, $\tilde{g}^2(T)$, through a renormalization scheme where the dimensional
reduction is optimal at the one-loop level. We then calculate the relevant
scale parameter, $\Lambda_T$, which characterizes the running of
$\tilde{g}^2(T)$ with $T$, using the background field method in the static
sector. It is found that $\Lambda_T/\Lambda_{\overline{\text{MS}}}
=e^{(\gamma_E+1/22)}/(4\pi)\approx 0.148$. We further verify that the coupling
$\tilde{g}^2(T)$ is also optimal for lattice perturbative calculations. Our
result naturally explains why the high temperature limit of QCD sets in at
temperatures as low as a few times the critical temperature. In addition, our
$\Lambda_T$ agrees remarkably well with the scale parameter determined from the
lattice measurement of the spatial string tension of the SU(2) gauge theory at
high $T$.


title: The Dilepton-Production Cross Section in Principal Value Resummation

abstract:
  Using a recent calculation of the perturbative hard part for dilepton
production that sums large threshold corrections to all orders in perturbative
QCD, we compute the corresponding cross sections. The hard part has been
evaluated using principal value resummation and contains all singular
momentum-dependent corrections. We also include a resummation of large Sudakov
terms, which are independent of parton momenta. We give predictions for the
dilepton-mass distribution, the rapidity distribution and the
rapidity-integrated $K$-factor at fixed-target energies and compare with
various experimental results in several kinematic regimes. We find that
principal value resummation produces cross sections that are finite and
well-behaved. For both protons and anti-protons on fixed targets, the resummed
cross sections are, in general, in excellent agreement with the data.


title:
The '3-1' model: the minimal model of calculable dynamical sypersymmetry
  breaking

abstract: paper is withdrawn - the model lacks a stable ground state


title:
Moments of lepton spectrum in B decays and the $m_b - m_c$ quark mass
  difference

abstract:
  It is argued that the quark mass difference $m_b-m_c$ can be extracted with a
high accuracy from experimental data on ratia of moments of lepton energy
spectrum in semileptonic decays of $B$ mesons. Theoretical expressions for the
moments are presented, which include perturbative as well as non-perturbative
corrections.


title: Four-fermion decay of Higgs bosons

abstract:
  We calculate four-fermion decays of a Higgs boson via $WW$ and/or $ZZ$
intermediate states for Higgs masses below $m_W$. We examine models with a
doubly-charged Higgs boson $H^{++}$ and show that the four-fermion decay is the
dominant mode for a wide range of parameter space. Existing searches for
$H^{++}$ in $Z$ decays have not looked for this mode. We also derive
four-fermion decay rate for a neutral Higgs boson.


title:
Limit on the Color-Triplet Higgs Mass in the Minimum Supersymmetric
  SU(5) Model

abstract:
  In the minimum supersymmetric SU(5) GUT, we derive the upper limit on the
mass of the color-triplet Higgs multiplets as $\mhc\leq 2.4\times 10^{16}~\GEV$
(90 \% C.L.) taking all possible corrections into account in a renormalization
group analysis. If the above upper limit is compared with a limit on $\mhc$
from the negative search for the proton decay; $\mhc \geq 2.0\times
10^{16}~\GEV$ (in which effects of the larger top-quark mass are included), the
minimum supersymmetric SU(5) GUT is severely constrained.


title: Solar Neutrino Data, Neutrino Magnetic Moments and Flavor Mixing

abstract:
  The results of all currently operating solar neutrino experiments are
analyzed in the framework of the resonant neutrino spin--flavor precession
scenario including the effects of neutrino mixing. Nine different profiles of
the solar magnetic field are used in the calculations. It is shown that the
available experimental data can be accounted for within the considered
scenario. The Ga--Ge data lead to an upper limit on the neutrino mixing angle:
$\sin 2\theta_0 \aprle 0.25$. One can discriminate between small mixing angle
($\sin 2\theta_0 \aprle 0.1$) and moderate mixing angle solutions by studying
the solar $\bar{\nu}_{e}$ flux which is predicted to be sizeable for moderate
mixing angles. The expected signals due to $\bar{\nu}_{e}$ in the SNO,
Super--Kamiokande and Borexino experiments are calculated and found to be
detectable for $\sin 2\theta_0 \aprge 0.1$.


title: Baryon Chiral Perturbation Theory A.D. 1994

abstract:
  In these lectures, the status of baryon chiral perturbation theory is
reviewed. Particular emphasis is put on the two--flavor sector and the physics
related to electromagnetic probes. I discuss in some detail the structure of
the effective Lagrangian at next--to--leading order, the meaning of low--energy
theorems in Compton scattering and pion photoproduction and confront the chiral
predictions with the existing data. Some remaining problems and challenges are
outlined.


title: The Production and Decay of Hybrid Mesons by Flux-Tube Breaking

abstract:
  An analytic calculation of the breaking of excited chromoelectric flux-tubes
is performed in an harmonic oscillator approximation and applied to predict the
dynamics of all $J^{PC}$ low-lying gluonic excitations of mesons (hybrids).
Widths, branching ratios and production dynamics of some recently discovered
$J^{PC} = 1^{-+}, 0^{-+}$ and $1^{--}$ mesons are found to be in remarkable
agreement with these results. We introduce the selection rules that can be used
to understand the systematics of numerical decay calculations and we find
possible significant breaking of these rules for specific channels that may
enable enhanced production and detection of hybrids.


title: Quark exchange model for charmonium dissociation in hot hadronic matter

abstract:
  A diagrammatic approach to quark exchange processes in meson-meson scattering
is applied to the case of inelastic reactions of the type
$(Q\barQ)+(q\barq)\rightarrow (Q\barq) + (q\barQ)$, where $Q$ and $q$ refer to
heavy and light quarks, respectively. This string-flip process is discussed as
a microscopic mechanism for charmonium dissociation (absorption) in hadronic
matter. The cross section for the reaction $J/\psi + \pi \to D+ \bar D$ is
calculated using a potential model, which is fitted to the meson mass spectrum.
The temperature dependence of the relaxation time for the $\J/Psi$ distribution
in a homogeneous thermal pion gas is obtained. The use of charmonium for the
diagnostics of the state of hot hadronic matter produced in ultrarelativistic
nucleus-nucleus collisions is discussed.


title: Spin symmetry predictions for heavy quarkonia alignment

abstract:
  We investigate the implications of spin symmetry for heavy quarkonia
production and decay. We first compare spin symmetry predictions for charmonia
and bottomonia radiative transitions with data and find they agree quite well.
We next use spin symmetry along with nonrelativistic QCD power counting to
determine the leading order alignment of P and D-wave orthoquarkonia that are
produced through gluon fragmentation. Finally, we discuss a mechanism which may
resolve the current factor of 30 discrepancy between theoretical predictions
and experimental measurements of prompt $\psi'$ production at the Tevatron.
This mechanism involves gluon fragmentation to a subleading Fock component in
the $\psi'$ wavefunction and yields 100\% transversely aligned $\psi'$'s to
lowest order. Observation of such a large alignment would provide strong
support for this resolution to the $\psi'$ problem.


title:
CP Violating Metastable States and Baryogenesis in the Hot Standard
  Model

abstract:
  We discuss a novel form of CP violation in the standard model. It takes place
at temperatures of the order of the electroweak transition, when two regions
with different values of the Wilson line are juxtaposed. This CP violation is
maximal. A sufficient condition is simply the existence of a long-lived
metastable state; this can occur for fewer than three generations, and also in
the minimal susy standard model. It leads to baryogenesis in all of these
models.


title: Multi-color QCD at High Energies and Exactly Solvable Lattice Theories

abstract:
  We examine the generalized leading-logarithmic approximation (LLA) equations
for compound states of n-reggeized gluons. It is shown that in multi-color QCD,
when $N_c \rightarrow \infty$, these equations have a sufficient number of
conservation laws to be exactly solvable. Holomorphic factorization of the wave
functions is used to reduce the corresponding quantum mechanical problem to the
solution of the one-dimensional Heisenberg model with the spins being the
generators of the M$\ddot{o}$bius group of conformal transformations.


title: Form factors for Charmed Baryon Decays at order 1/m_c in the HQET limit

abstract:
  We study the vector and axial vector form factors in the heavy to light
transitions in charmed baryon decays using HQET. We calculate the 1/m_c
corrections to the form factors and show that these corrections can be
significant. We also consider applications to semi-leptonic and hadronic decays
of charmed baryons.


title: Bose-Einstein Correlations for Systems with Large Halo

abstract:
  Model-independent considerations are presented for the calculation of
Bose-Einstein correlation functions and momentum distributions which describe
boson-emitting systems containing a central part surrounded by a large halo. If
the characteristic geometrical size of the halo is sufficiently large, the
contributions of central part and the halo to the invariant momentum
distribution are shown to be separable. The momentum-dependence of the
intercept parameter of the correlation function plays a central role. Almost
all high energy reactions including lepton-lepton, lepton hadron, hadron-hadron
and nuclear reactions are shown to be interpretable as boson emitting systems
with large halo. The results are applied to certain high energy heavy ion data
at CERN SPS. New insights are obtained for the description of low transverse
momentum enhancement of pions.


title: Perturbative QCD Analysis of $B$ Meson Decays

abstract:
  Resummation of large QCD radiative corrections, including leading and
next-to-leading logarithms, in pion electromagnetic form factor is reviewed.
Similar formalism is applied to exclusive processes involving heavy mesons, and
leads to Sudakov suppression for the semi-leptonic decay $B\to\pi l\nu$. It is
found that, with the inclusion of Sudakov effects, perturbative QCD analysis of
this decay is possible for the energy fraction of the pion above 0.3. By
combining predictions from the soft pion theorems, we estimate that the upper
limit of the KM matrix element $|V_{ub}|$ is roughly 0.003.


title:
Relativistic Three-Dimensional Two- and Three-Body Equations on a Null
  Plane and Applications to Meson and Baryon Regge Trtajectories

abstract:
  We start from a field-theoretical model of zero range approximation to derive
three-dimensional relativistic two- and three-body equations on a null plane.
We generalize those equations to finite range interactions. We propose a
three-body null-plane equation whose form is different from the one presented
earlier in the framework of light-cone dynamics. We discuss the choices of the
kernels in two- and three-body cases and apply our model to the description of
meson and baryon Regge trajectories. Our approach overcomes some theoretical
and phenomenological difficulties met in preceding relativized treatments of
the three-body problem.


title: Review on Physics of $e^+e^- \to t\bar{t}$ Near Threshold$^*$

abstract:
  We review the recent developments of studies on $e^+ e^- \to t\bar{t}$ in the
threshold region. It has been shown that the top threshold cross sections will
be able to provide many important and interesting physics. Due to the large
mass and the large decay width of top quark, there will appear a number of
unique features at top threshold. First, theoretical background is summarized.
Then we present observables that are typical to the top threshold region, and
discuss the physics that can be extracted. Also, we list the results of the
recent parameter determination study taking a sample case of $m_t = 170$~GeV.


title: Semileptonic Kaon Decays

abstract:
  We present the matrix elements for the semileptonic kaon decays
$K_{l2\gamma}$ , $K_{l2l^+l^-}$, $K_{l2l'^+l'^-}$,$K_{l3}$, $K_{l3\gamma}$ and
$K_{l4}$ at next-to-leading order, and $K_{e5}$ at leading order in Chiral
Perturbation Theory and compare the predictions with experimental data. For
$K_{l4}$ decays we estimate yet higher orders in order to reduce theoretical
uncertainties in the comparison with the data. Monte Carlo event generators are
used to calculate the corresponding rates at DA$\Phi$NE. We discuss the
possibilities to improve our knowledge of the low-energy structure of the
Standard Model at this and similar machines.


title: Infrared Renormalons and Power Corrections in Deep-Inelastic Sum Rules

abstract:
  Infrared renormalons and $1/Q^2$ power corrections in deep-inelastic sum
rules are studied. The renormalization of operators with power divergence are
discussed. The higher-twist terms in the operator product expansion are shown
to account for the residual soft contributions survived from the
Kinoshita-Lee-Nauenberg type of cancellation in Feynman diagrams. The presence
of some degree of arbitrariness in the twist separation allows one to define
the most convenient higher-twist operators suitable for a particular
non-perturbative method. The discussion is focused on the Bjorken sum rule, for
which the $1/Q^2$ corrections are considered on a lattice.


title: Electroweak Condensates at Standard Top Mass Values

abstract:
  In the two Higgs doublet model, perturbativity breaks down below the Planck
scale: For top mass values 170-180 GeV, the Yukawa coupling reaches the pole
below 1000 TeV, if the ratio of vev's v_u/v_d is below 1. We discuss top
condensate scenarios for 150 GeV < m_top < 200 GeV, showing that a version with
two composite Higgses is a viable option. Within electroweak gauge extensions
the second Higgs does not come with additional parameters, but is dictated by
the symmetry.


title: Higgs and Z boson decays into light gluinos

abstract:
  We calculate the decay rate of scalar and pseudoscalar Higgs bosons into a
pair of gluinos, within the Minimal Supersymmetric Standard Model. In the
theoretically and experimentally allowed light gluino window, $\mg \sim $ 3--5
GeV, gluino pairs can completely dominate the decays of the light scalar Higgs
boson and play a prominent role in the decay of the pseudoscalar Higgs boson.
This would alter the limits obtained from $Z$ decays on the lightest CP--even
and CP--odd Higgs bosons, and could jeopardize the search for these Higgs
particles at future hadron colliders. In contrast, the branching ratio for the
two--body decay of $Z$ bosons into pairs of light gluinos is less than 0.1\%.


title:
Simple Radiative Neutrino Mass Matrix for Solar and Atmospheric
  Oscillations

abstract:
  A simple 3 X 3 neutrino mass matrix is proposed to accommodate both the solar
and atmospheric neutrino deficits. This scenario can be realized naturally by a
radiative mechanism for the generation of neutrino masses. It also goes
together naturally with electroweak baryogenesis and cold dark matter in a
specific model.


title: Radiative Corrections to the Decay $\tau\to\pi\nu_\tau$

abstract:
  We have calculated the radiative corrections to the decay $\tau\to \pi(K)
\nu_\tau$, taking to account internal bremsstrahlung and structure dependent
radiation in the radiative decay and point meson, hadronic structure dependent
and short distance contributions in the virtual corrections. We display the
spectra of the photon energy and of the pion-photon invariant mass in the decay
$\tau\to\pi\nu_\tau\gamma$ and compare with the PHOTOS Monte-Carlo. Our result
for the radiative correction to the ratio $\Gamma(\tau\to\pi\nu_\tau(\gamma))/
\Gamma(\pi\to\mu\nu_\mu(\gamma))$ is $\delta R_{\tau/\pi} = \left(0.16 \pm 0.14
\right) \%$ and for the ratio $\Gamma(\tau\to K\nu_\tau(\gamma))/
\Gamma(K\to\mu\nu_\mu(\gamma))$, we obtain $\delta R_{\tau/K } = \left(0.90 \pm
0.22 \right) \%$.


title:
Charm Production in Hadronic and Heavy-Ion Collisions at RHIC and LHC
  Energies to $O(\alpha_s^3)$

abstract:
  We present results on rapidity and transverse momentum distributions of
inclusive charm quark production in hadronic and heavy-ion collisions at RHIC
and LHC energies, including the next-to-leading order, $O(\alpha_s^3)$,
radiative corrections and the nuclear shadowing effect. We determine the
hadronic and the {\it effective} (in-medium) K-factor for the differential and
total inclusive charm cross sections. We find the fraction of central and
inelastic events that contain at least one charm quark pair at LHC energies and
obtain the effective $A$-dependence of the inclusive charm production in
proton-nucleus and nucleus-nucleus collisions at RHIC and in nucleus-nucleus
collisions at the LHC. We discuss theoretical uncertainties inherent in our
calculation. In particular, we show how different extrapolations of gluon
density in a nucleon {\em and} in a nucleus to the low-$x$ region introduce
large theoretical uncertainty in the calculation of charm production at LHC
energies.


title: Tests for Tau's Charged-Current Structure

abstract:
  The Lorentz structure of the tau lepton's charged-current can almost be
completely determined by use of stage-two spin-correlation functions for the
$\{\rho ^{-},\rho ^{+}\}$ and $\{a_1^{-},a_1^{+}\}$ decay modes It is possible
to test for a ``(V-A) + something'' structure in the ${J^{Charged}}_{Lepton}$
current, so as to bound the scales $\Lambda$ for ``new physics" such as arising
from tau weak magnetism, weak electricity, and/or second-class currents.


title:
A Nonperturbative, Schwinger-Dyson-Equation Analysis of Quark Masses and
  Mixings in a Model with QCD and Higgs Interactions

abstract:
  The Landau gauge Schwinger-Dyson Equation for the quark self-energy is solved
in the quenched ladder approximation for several cases of one- and
two-quark-generations. The exchanges of Standard Model gluons and Higgs bosons
are taken into account. It is found that Higgs boson exchange dominates the
quark self-energy for sufficiently large input quark masses (>75 GeV), causing
the running quark propagator mass to increase with energy-scale. The running of
the quark mixing angles is also considered. No running of the quark mixing
angles is found, to one part in a billion, for input quark masses up to and
including 500 GeV.


title: Physics Prospects at the Hadron Colliders

abstract:
  I start with a brief introduction to the elementary particles and their
interactions, Higgs mechanism and supersymmetry. The major physics objectives
of the Tevatron and LHC colliders are identified. The status and prospects of
the top quark, charged Higgs boson and superparticle searches are discussed in
detail, while those of the neutral Higgs boson(s) are covered in a parallel
talk by R.J.N. Phillips at this workshop.


title:
Complete Initial State Radiation to off-Shell $Z^0$~PAIR Production in
  $e^+e^-$~ANNIHILATION

abstract:
  A cross-section calculation for the Standard Model reaction $e^+e^-
\rightarrow (Z^0Z^0) \rightarrow f_1\bar{f_1}f_2\bar{f_2}$ including the
effects of the finite $Z^0$~width and initial state radiative corrections is
presented. The angular phase space integrations are performed analytically,
leaving the invariant masses for numerical integration. Semi-analytical and
numerical results in the energy range $\sqrt{s}=150\;GeV$ to $1\;TeV$ are
reported.


title: Vacuum polarization correction to the positronium decay rate

abstract:
  Corrections $\sim \alpha^2 $ to the positronium decay rate, induced by
one--loop vacuum polarization diagram, are calculated. Their relative values
are $0.4468(3)(\alpha/\pi)^2$ for para- and $0.960(3)(\alpha/\pi)^2$ for
orthopositronium.


title: Renormalized sum rules for structure functions of heavy mesons decays

abstract:
  We consider properties of the structure functions of inclusive heavy meson
decays $B\to X_c$ and treat the $c$ quark mass as a free parameter. We show
that in two extreme cases of heavy and light $c$ quark the structure functions
of heavy--heavy and heavy--light transitions are given by a Fourier transform
of the matrix elements of Wilson lines containing a time--like and a
light--like segment, correspondingly. Using the renormalization properties of
Wilson lines we find the dependence of the structure functions on the
factorization scale, the structure function of heavy--heavy transition is
renormalized multiplicatively while that of heavy-light transition obeys the
GLAP--type evolution equation. We propose a generalization of the sum rules for
the moments of the structure functions (Bjorken, Voloshin, and the ``third''
sum rules) with a soft exponential factorization cut--off, which correctly
incorporates both perturbative and nonperturbative effects. We analyze
nonperturbative corrections by first considering infrared renormalon
contributions to the Wilson lines. Uncertainties induced by the leading
renormalon pole at $u=\frac12$ are exactly cancelled by the similar uncertainty
in the heavy quark pole mass. The leading nonperturbative corrections
associated with the next renormalon at $u=1$ are parameterized by the matrix
element $\mu_\pi^2$ which is proportional to the heavy quark kinetic energy.


title: Triplet Higgs bosons at $e^+e^-$ colliders

abstract:
  We investigate the possibility of probing the triplet Higgs boson sector via
single charged Higgs production in the process $e^+ e^- \to H^+ l \nu_l$, at
high energy electron-positron colliders, using the tree level $H^+W^-Z$
coupling which is a unique feature of such models. We find that even LEP-200
can give nontrivial information upto $M_{H^{\pm}} \simeq 120 $ GeV if the
doublet -triplet mixing is not restricted by the current value of the $\rho$
parameter which is the case in models with a custodial symmetry. Further we
point out that in such models, the 4-body, tree level decay $H^+ \to W^*Z^* \to
4$ fermions dominates and hence provides a very clean signal when the four
fermions are leptons. At NLC the discovery range for the charged Higgs in
triplet models via this process is $\sim 400$ GeV.


title: Introduction to the Physics of Higgs Bosons

abstract:
  A basic introduction to the physics of the Standard Model Higgs boson is
given. We discuss Higgs boson production in $e^+e^-$ and hadronic collisions
and survey search techniques at future accelerators. The Higgs bosons of the
minimal SUSY model are briefly considered. Indirect limits from triviality
arguments, vacuum stability and precision measurements at LEP are also
presented.