title: Endpoint of the hot electroweak phase transition

abstract:
  We give the nonperturbative phase diagram of the four-dimensional hot
electroweak phase transition. The Monte-Carlo analysis is done on lattices with
different lattice spacings ($a$). A systematic extrapolation $a \to 0$ is done.
Our results show that the finite temperature SU(2)-Higgs phase transition is of
first order for Higgs-boson masses $m_H<66.5 \pm 1.4$ GeV. At this endpoint the
phase transition is of second order, whereas above it only a rapid cross-over
can be seen. The full four-dimensional result agrees completely with that of
the dimensional reduction approximation. This fact is of particular importance,
because it indicates that the fermionic sector of the Standard Model can be
included perturbatively. We obtain that the Higgs-boson endpoint mass in the
Standard Model is $72.4 \pm 1.7$ GeV. Taking into account the LEP Higgs-boson
mass lower bound excludes any electroweak phase transition in the Standard
Model.


title: Z-Decays to b Quarks and the Higgs Boson Mass

abstract:
  A model independent analysis of the most recent averages of precision
electroweak data from LEP and SLD finds a 3$\sigma$ deviation of the parameter
$A_b$ from the Standard Model prediction.
  The fitted value of $m_H$ shows a strong dependence on the inclusion or
exclusion of b quark data, and the Standard Model fits have poor confidence
levels of a few percent when the latter are included.
  The good fits obtained to lepton data, c quark data and the directly measured
top quark mass, give $m_t = 171.2_{-3.8}^{+3.7}$ GeV and indicate that the
Higgs boson mass is most likely less than 200 GeV.


title: Where does the hot electroweak phase transition end?

abstract:
  We give the nonperturbative phase diagram of the four-dimensional hot
electroweak phase transition. A systematic extrapolation $a \to 0$ is done. Our
results show that the finite temperature SU(2)-Higgs phase transition is of
first order for Higgs-boson masses $m_H<66.5 \pm 1.4$ GeV. The full
four-dimensional result agrees completely with that of the dimensional
reduction approximation. This fact is of particular importance, because it
indicates that the fermionic sector of the Standard Model (SM) can be included
perturbatively. We obtain that the Higgs-boson endpoint mass in the SM is $72.4
\pm 1.7$ GeV. Taking into account the LEP Higgs-boson mass lower bound excludes
any electroweak phase transition in the SM.


title: Implications of Isospin Conservation in $\Lambda_b$ Decays and Lifetime

abstract:
  We consider isospin predictions for the semi-leptonic and non-leptonic decays
of the $\Lambda_b$ baryon. Isospin conservation of the strong interactions
constrains the possible final states in $\Lambda_b$ decays. Since the baryon
hyperfine splittings depend upon light quark dynamics and do not decrease with
increasing heavy quark mass, this leads in general to to phase space
enhancements in $\Lambda_b$ decays relative to $B$ meson decays for the same
underlying quark transitions. Consequently the $\Lambda_b$ lifetime is smaller
than the $B$ lifetime. Phase space enhancements in $\Lambda_b$ decays relative
to $B$ decays can be understood in terms of hyperfine interactions in the heavy
quark system.


title: Heavy quark confinement from Dyson Schwinger equations

abstract:
  A formalism for studying the confinement of heavy quarks by considering the
renormalised quark Dyson-Schwinger equation in the limit m --> infinity is
described. We are particularly interested in studying the analytic structure of
heavy quark propagators in the region of the complex momentum plane close to
the bare fermion mass pole.


title: Stochastic interpretation of Kadanoff-Baym equations

abstract:
  We show that the nonperturbative transport equations, the so called
`Kadanoff-Baym equations', within the non-equilibrium real time Green's
function description can be be understood as the ensemble average over
stochastic equations of Langevin type. For this we couple a free scalar boson
quantum field to an environmental heat bath with some given temperature T. The
inherent presence of noise and dissipation related by the
fluctuation-dissipation theorem guarantees that the modes or particles become
thermally populated on average in the long-time limit. This interpretation
leads to a more intuitive physical picture of the process of thermalization and
of the interpretation of the Kadanoff-Baym equations. One also immediately
understands that the emerging wave equations for long wavelength modes with
momenta much smaller than temperature behave nearly as classical fields. We
also demonstrate how the problem of so called pinch singularities is resolved
by a clear physical necessity of damping within the one-particle propagator.
The occurrence of such ill-defined terms arising solely in a strictly
perturbative expansion in out of equilibrium quantum field theory has a natural
interpretation in analogy to Fermi's golden rule.


title: Flavor Physics in the Supergravity Model

abstract:
  Phenomenological aspects of flavor changing processes are considered in the
context of the supergravity model.Various flavor changing neutral current
processes in B and K decays are calculated in such models. For lepton flavor
violating processes the $\mu^+ \to e \gamma$ branching ratio and the T odd
triple vector correlation for the $\mu^+ \to e^+ e^+ e^-$ process are
investigated in the SU(5) SUSY GUT. Possibility to find SUSY effects through
these Flavor changing processes in future experiments are also discussed.


title:
Bounds of the mass of Z' and the neutral mixing angles in general
  SU(2)_L x SU(2)_R x U(1) models

abstract:
  We consider phenomenological constraints on the mass $M_{Z^{\prime}}$ and the
two mixing angles $\theta_R$ and $\xi$ of the neutral sector in a very general
class of $SU(2)_L \times SU(2)_R \times U(1)$ models using electroweak data. We
do not make any specific assumptions such as left-right symmetry or the Higgs
structure. The analysis of the neutral sector has the advantage that it has
relatively fewer parameters compared to the charged sector since the
Cabibbo-Kobayashi-Maskawa (CKM) matrix elements in the right-handed sector do
not enter into the analysis, hence the number of various possibilities from a
big parameter space is reduced. We utilize theoretical considerations on the
masses of the gauge particles and the mixing angles. We combine the precision
electroweak data from LEP I and the low-energy neutral-current experimental
data to constrain the parameters introduced in the model. It turns out that
$M_{Z^{\prime}}> 400$ GeV, $-0.0028 <\xi <0.0065$ with little constraint on
$\theta_R$. In the left-right symmetric theory, $M_{Z^{\prime}}$ should be
larger than 900 GeV. With these constraints, we compare the values for $\sigma
(e^+ e^- \to \mu^+ \mu^-)$, $\sigma (e^+ e^- \to b\bar{b})$ and $A_{FB}^{\ell}$
at LEP II with experimental values.


title:
The non-singlet QCD evolution kernels improved by renormalon chain
  contributions

abstract:
  Closed expressions are presented for the contributions to QCD non-singlet
forward evolution kernels $P(z)$ for the DGLAP equation and to $V(x,y)$ for
non-forward (ER-BL) evolution equation for a certain class of diagrams which
include renormalon chains. Calculations are performed in covariant $\xi$-gauge,
in the \MSbar scheme. The assumption of "naive nonabelianization" approximation
for kernel calculations is discussed, and a special choice of the gauge
parameter $\xi=-3$ is analyzed in this context. Partial solutions to the ER-BL
evolution equation are obtained.


title: Charmonium Suppression in Heavy Ion Collisions by Prompt Gluons

abstract:
  In relativistic heavy ion collisions, also the bremsstrahlung of gluons in
the fragmentation regions of the nuclei suppresses the produced charmonium
states. In the energy range of the SPS, the radiation of semi-hard gluons
occurs in the Bethe-Heitler regime and the density of gluons and therefore the
suppression goes like $(AB)^{1\over3}$, where $A$ and $B$ are the nucleon
numbers of the projectile and target nuclei. In contrast, the suppression via
collisions with nucleons is proportional to $(A^{1\over3} + B^{1\over3})$.
Parameter free perturbative QCD calculations are in a good agreement with the
data on $J/\Psi$ and $\Psi'$ suppression in heavy ion collisions at SPS CERN.
At higher energies (RHIC, LHC) the number of gluons which are able to break-up
the charmonium substantially decreases and the additional suppression is
expected to vanish.


title: $d=5$ operators in SUSY GUT: fermion masses versus proton decay

abstract:
  In the minimal SU(5) SUSY GUT $d =5$ operators lead to $p\to K^+ \nu$ decay
with the proton life time of the order of $10^{28}$ years for the natural
choice of the parameters of the theory. This value is in strong contradiction
with experimental bound $\tau_{p\to K\nu} > 10^{32}$ years. $d=5$ operators are
induced by colored Higgsino exchanges and are closely (through SU(5) and super
symmetry) related to another wrong prediction of SU(5) SUSY GUT: $m_d /m_s =
m_e /m_{\mu}$. We demonstrate how in the model where reasonable pattern of
quark and lepton masses and CKM mixing angles are obtained proton decay can be
suppressed and proton life time can be close to the present experimental bound.


title: Towards the Extraction of the CKM Angle $\gamma$

abstract:
  The determination of the angle $\gamma$ of the unitarity triangle of the CKM
matrix is regarded as a challenge for future $B$-physics experiments. In this
context, the decays $B^\pm\to \pi^\pm K$ and $B_d\to\pi^\mp K^\pm$, which were
observed by the CLEO collaboration last year, received a lot of interest in the
literature. After a general parametrization of their decay amplitudes,
strategies to constrain and determine the CKM angle $\gamma$ with the help of
the corresponding observables are reviewed. The theoretical accuracy of these
methods is limited by certain rescattering and electroweak penguin effects. It
is emphasized that the rescattering processes can be included in the bounds on
$\gamma$ by using additional experimental information on $B^\pm\to K^\pm K$
decays, and steps towards the control of electroweak penguins are pointed out.
Moreover, strategies to probe the CKM angle $\gamma$ with the help of $B_s\to
K\bar{K}$ decays are briefly discussed.


title:
Constraint on the Isgur-Wise function for \bar B --> D semileptonic
  decays

abstract:
  A current algebra sum rule for inclusive decays \bar B --> D + X + \ell +
\bar \nu by Bjorken et al. is used to obtain constraints on the Isgur-Wise
function \xi(\omega) for \bar B --> D \ell \bar \nu decays.


title: CP violation in the mass matrix of heavy neutrinos

abstract:
  We discuss the question of CP-violation in the effective Hamiltonian approach
in models of leptogenesis through heavy right handed neutrino decays. We first
formulate the problem in four component notation and then point out that before
the heavy neutrinos have decayed away, the universe becomes CP-asymmetric in
the heavy neutrinos. However, the lepton asymmetry generated after they
completely decay are independent of this asymmetry.


title: News from the lattice

abstract:
  A summary of some recent results from lattice simulations is presented. These
include first calculations of the strangeness magnetic moment of the nucleon,
three new studies of the gluon propagator, flux tube attraction in U(1) gauge
theory, and the static-quark potential and its gluonic excitations.


title:
Determining the relative size of the CP-even and CP-odd Higgs Boson
  Couplings to a Fermion at the LHC

abstract:
  We demonstrate that the relative size of the CP-even and CP-odd couplings of
a Higgs boson to $t\anti t$ can be determined at the LHC at a level that is
very useful in discriminating between models, provided that a Higgs signal can
be observed at a reasonable $S/\sqrt B$ level in the $t\anti t\h$ (with
$\h\to\gamma\gamma$ or $b\anti b)$ channels. In particular, the CP-even nature
of a SM-like Higgs boson's coupling to $t\anti t$ can be confirmed with very
substantial statistical significance using the $t\anti t \h$ ($\h\to
\gamma\gamma$) production/decay mode. The key to achieving good discrimination
between models is to make full use of the difference in the final state
distributions for different ratios of the CP-even to CP-odd couplings. For our
analysis, we employ the very convenient and simple optimal analysis procedures
derived previously.


title: Large Lepton Mixing in Seesaw Models - Coset-space Family Unification -

abstract:
  We show that the large mixing between $\nu_\mu$ and $\nu_\tau$ observed by
the SuperKamiokande collaboration is a quite natural prediction in a large
class of seesaw models. This large mixing is basically due to the unparallel
family structure suggested from the observed mass hierarchies in quark and
lepton mass matrices. We show that the unparallel family structure is
automatically realized in ``coset-space family unification'' model based on
$E_7/SU(5) \times U(1)^3$. This model also suggests the small angle MSW
solution to the solar neutrino problem.


title: Is the resonance D(2637) really a radial excitation?

abstract:
  We consider various possible identifications of the quantum numbers of the
resonance D(2637) recently observed by DELPHI in the $D^*\pi\pi$ channel. We
argue that in spite of a good agreement of the measured mass with the
quark-model prediction for the radial excitation, a total width as small as
$\le 15$ MeV is hardly compatible with its identification as a radial charm
excitation. The $J^{P}=2^{-}, 3^{-}$ orbitally excited mesons with such a mass
could have widths of the observed order of magnitude. However in this case one
would expect two neighbouring states with the mass difference of about 30-50
MeV corresponding to the nearly degenerate components of the heavy- meson
multiplet with light-quanta angular momentum j=5/2, and moreover, according to
the quark-model predictions the mass of the orbital excitation should be more
than 50 MeV larger than 2637 MeV. Thus we conclude that, at present, we find no
fully convincing understanding of the quantum numbers of the observed
resonance.


title: Systematics of Leading Particle Production

abstract:
  Using a QCD inspired model developed by our group for particle production,
the Interacting Gluon Model (IGM), we have made a systematic analysis of all
available data on leading particle spectra. These data include diffractive
collisions and photoproduction at HERA. With a small number of parameters
(essentially only the non-perturbative gluon-gluon cross section and the
fraction of diffractive events) good agreement with data is found. We show that
the difference between pion and proton leading spectra is due to their
different gluon distributions. We predict a universality in the diffractive
leading particle spectra in the large momentum region, which turns out to be
independent of the incident energy and of the projectile type.


title: Observational constraints on an inflation model with a running mass

abstract:
  We explore a model of inflation where the inflaton mass-squared is generated
at a high scale by gravity-mediated soft supersymmetry breaking, and runs at
lower scales to the small value required for slow-roll inflation. The running
is supposed to come from the coupling of the inflaton to a non-Abelian gauge
field. In contrast with earlier work, we do not constrain the magnitude of the
supersymmetry breaking scale, and we find that the model might work even if
squark and slepton masses come from gauge-mediated supersymmetry breaking. With
the inflaton and gaugino masses in the expected range, and $\alpha = g^2/4\pi $
in the range $10^{-2}$ to $10^{-3}$ (all at the high scale) the model can give
the observed cosmic microwave anisotropy, and a spectral index in the observed
range. The latter has significant variation with scale, which can confirm or
rule out the model in the forseeable future.


title:
Determination of the Weak Phase gamma from Rate Measurements in B^+- ->
  pi K, pi pi Decays

abstract:
  A method is described which, under the assumption of SU(3) symmetry, allows
one to determine the angle gamma=Arg(Vub^*) of the unitarity triangle from
time-independent measurements of the branching ratios for the decays B^+ ->
pi^0 K^+ and B^- -> pi^0 K^-, as well as of the CP-averaged branching ratios
for the decays B^+- -> pi^+- K^0 and B^+- -> pi^+- pi^0. The effects of
electroweak penguin operators are included in a model-independent way, and
SU(3)-breaking corrections are accounted for in the factorization
approximation.


title:
A relativistic chiral quark model for pseudoscalar emission from heavy
  mesons

abstract:
  The amplitudes for one-pion mediated transitions between heavy meson excited
states are obtained in the framework of the relativistic chiral quark model.
The effective coupling constants to pions and the decay widths of excited heavy
mesons with l<=2 for non-radially excited, and the l=0 radially excited mesons
are presented for both charmed and beauty mesons. We also discuss the allowed
decays of strange excited heavy mesons by emission of a K-meson.


title:
Antibaryon density in the central rapidity region of a heavy ion
  collision

abstract:
  We consider (anti-)baryons production in heavy ion collisions as production
of topological defects during the chiral phase transition. Non-zero quark
masses which explicitly break chiral symmetry supress the (anti-)baryon
density. Hardly any (anti-)baryons will be produced in the central rapidity
region of a heavy ion collision.


title: High p_T Phenomena in Heavy Ion Collisions at s^1/2=20 and 200 AGeV

abstract:
  Jet quenching as observed via high p_T hadron production is studied in the
HIJING1.35 model. We test the model on recent WA98 data on 160 AGeV Pb+Pb ->
pi0 up to 4 GeV/c. The results depend sensitively on the model of the Cronin
effect. At (RHIC) collider energies (s^1/2 > 200 AGeV), on the other hand,
semi-hard hadron production becomes insensitive to the above model and is thus
expected to be a cleaner probe of jet quenching signature associated with
non-Abelian radiative energy loss.


title:
Implications of the $\nu_\mu \to \nu_s$ solution to the atmospheric
  neutrino anomaly for early Universe cosmology

abstract:
  By numerically solving the quantum kinetic equations we compute the range of
parameters where the $\nu_\mu \to \nu_s$ oscillation solution to the
atmospheric neutrino anomaly is consistent with a stringent big bang
nucleosynthesis (BBN) bound of $N_{eff}^{BBN} \stackrel{<}{\sim} 3.6$. We show
that this requires tau neutrino masses in the range $m_{\nu_\tau} \stackrel
{>}{\sim} 4 eV$ (for $|\delta m^2_{atm}| = 10^{-2.5} eV^2$). We discuss the
implications of this scenario for hot+cold dark matter, BBN, and the anisotropy
of the cosmic microwave background.


title:
Evolution equation for the heavy quark distribution function in the
  parton model approach

abstract:
  We explore the perturbative QCD corrections to the inclusive semileptonic
decays of $B$ mesons. In inclusive $B$ decay processes the parton picture works
well and the scaling feature manifests because the mass of $b$ quark is larger
than the QCD scale. Due to this property, the decay rate may be expressed by a
single structure function describing the light-cone distribution of $b$ quark
apart from the kinematic factor. We derive a $q^2$ evolution equation for the
distribution function, which violates the scaling property through the
Altarelli-Parisi type approach. The evolution equation is numerically solved
and its phenomenological implications are also discussed.


title:
Phase Structure of the Massive Scalar phi^4 Model at Finite Temperature
  -- Resummation Procedure a la RG improvement --

abstract:
  In this paper a resummation method inspired by the renormalization-group
improvement is applied to the one-loop effective potential (EP) in massive
scalar $\phi^4$ model at $T\neq0$. By investigating the phase structure of the
model at $T \neq 0$ we get the following observations; i) Starting from the
perturbative calculations with the theory renormalized at an arbitrary
mass-scale $\mu$ and at an arbitrary temperature $T_0$, we can in principle
fully resum terms of $O(\lambda T/\mu)$ together with terms of $O(\lambda
(T/\mu)^2)$. The key idea is to fix the arbitrary RS-parameters so as to make
both of one-loop radiative corrections to the mass as well as to the coupling
vanish, ensuring the function form of the EP to be determined up to the
next-to-leading order of large correction terms, thus absorbing completely
those terms of $O(\lambda (T/\mu)^2)$ and of $O(\lambda T/\mu)$. ii) If we
start from the theory renormalized at the temperature of the environment $T$,
the $O(\lambda (T/\mu)^2)$-term resummation can be simply completed through the
$T$-renormalization itself. With the lack of freedom we can set only one
RS-fixing condition to absorb the large terms of $O(\lambda T/\mu)$, thus only
the partial resummation of these terms can be carried out. iii) In the above
two analyses the temperature-dependent phase transition of the model is shown
with the analytic evaluation to proceed through the second order transition.
The critical exponents are estimated analytically and are compared with those
in other analyses. iv) Our resummation method does not work if we start from
the theory renormalized at T=0.


title:
Can one discriminate the thermal dilepton signal against the open charm
  and bottom decay background in ultrarelativistic heavy-ion collisions?

abstract:
  In ultrarelativistic heavy-ion collisions at $\sqrt{s} >$ 20 (120)
A$\cdot$GeV a copious production of charm (bottom) production sets in which,
via correlated semileptonic $D \bar D$ ($B \bar B$) decays, gives rise to a
dilepton yield at invariant mass $M \approx$ 2 -- 3 GeV in excess of the
Drell-Yan yield and the thermal dilepton signal from deconfined matter as well.
We show that appropriate single-electron transverse momentum cuts (suitable for
ALICE at LHC) cause a threshold like behavior of the dilepton spectra from
heavy-quark meson decays and the Drell-Yan process and can allow to observe a
thermal dilepton signal from hot deconfined matter.


title: Production of Supersymmetric Particles at High-Energy Colliders

abstract:
  The production and decay of supersymmetric particles is presented. The
dependence of the hadro-production cross section for weakly and strongly
interacting yields an improvement of derived mass bounds or the measurement of
the masses, respectively, of neutralinos/charginos and stops at the Tevatron
and at the LHC. Moreover, the NLO corrections increase the predicted
neutralino/chargino cross section by +20% to +40%, nearly independent of the
mass of the particles. The consistent treatment as well as the phenomenological
implications of scalar top mixing are presented. The correction to the stop
production cross sections, depending on the fraction of incoming quarks and
gluons, varies between -10% to +40% for an increasing fraction of incoming
gluons. The dependence of this cross section on all parameters, except for the
masses of the produced particles, is negligible.


title:
On Transverse Momentum Event--by--Event Fluctuations in String Hadronic
  Models

abstract:
  Transverse momentum event-by-event fluctuations are studied within the
string-hadronic model of high energy nuclear collisions, LUCIAE. Data on
non-statistical pT fluctuations in p+p interactions are reproduced.
Fluctuations of similar magnitude are predicted for nucleus-nucleus collisions,
in contradiction to the preliminary NA49 results. The introduction of a string
clustering mechanism (Firecracker Model) leads to a further, significant
increase of pT fluctuations for nucleus-nucleus collisions. Secondary hadronic
interactions, as implemented in LUCIAE, cause only a small reduction of pT
fluctuations.


title: Sudakov Effects in Electroweak Corrections

abstract:
  In perturbation theory the infrared structure of the electroweak interactions
produces large corrections proportional to double logarithms log^2 (s/m^2),
similar to Sudakov logarithms in QED, when the scale s is much larger than the
typical mass m of the particles running in the loops. These energy growing
corrections can be particularly relevant for the planned Next Linear Colliders.
We study these effects in the Standard Model for the process e+ e^->f fbar and
we compare them with similar corrections coming from SUSY loops.


title:
Is the lepton flavour changing observable in $Z \to \mu^\pm + \tau^\mp$
  decay?

abstract:
  Neutrino oscillations as suggested by the recent Super-Kamiokande result
imply that lepton numbers could be violated, and Z$\to \mu^{\mp} +\tau^{\pm}$
is a typical manifestation. We point out that for this mode, the GIM
cancelation is much milder with only a logarithmic behavior $\log (m_3 /m_2)$
where $m_j$ is the neutrino mass. The ratio $\Gamma$(Z $\to \mu^{\mp} +
\tau^{\pm})/\Gamma($Z $ \to \mu^{-} + \mu^{+})$ could be about
$10^{-5}-10^{-6}$, in sharp contrast with the vanishingly small rate
$\tau^{\pm}\to \mu^{\pm} + \gamma$ strongly suppressed by a quadratic power
$(m_3^2-m_2^2)/ M_{\rm W}^2$. Being complementary to neutrino oscillation
experiments, measurements of Z$\to \mu^{\mp} +\tau^{\pm}$ -- which are at hand
with the present colliders -- would give one more constraint to the lepton
mixing angle $\sin 2\theta_{jk}$ and the neutrino mass ratio $m_j/m_k$.


title: Oscillating Effects in the Nambu -- Jona-Lasinio Model

abstract:
  Phase structure of the four dimensional Nambu -- Jona-Lasinio model has been
investigated in two cases: 1) in nonsimply connected space-time of the form
$R^3\times S^1$ (space coordinate is compactified and the length of the circle
$S^1$ is $L$) with nonzero chemical potential $\mu$ and 2) in Minkowski
space-time at nonzero values of $\mu,H$, where $H$ is the external magnetic
field. In both cases on phase portraits of the model there are infinitly many
massless chirally symmetric phases as well as massive ones with spontaneously
broken chiral invariance. Such phase structure leads unavoidably to
oscillations of some physical parameters at $L\to\infty$ or $H\to 0$, including
magnetization, pressure and particle density of the system as well as quark
condensate and critical curve of chiral phase transitions.


title: Scalar and Vector Mixings in $(SU(2)\times U(1))$ Models

abstract:
  We study the possible mixings between gauge vector fields and scalar fields
through their self-energies, arising in models with two Higgs doublets. We
derive the relevant set of Schwinger-Dyson equations and the Ward identities
that compel the longitudinal parts of the field propagators. Linear $(R_{\xi})$
gauge is used and the results are given at all orders in perturbative theory,
and some particular aspects of the one loop case are stressed.


title: Probing Quark-Gluon Correlation Functions

abstract:
  We review applicability of QCD factorization theorem to multiple scattering
in deeply inelastic lepton-nucleus scattering. We show why A^{1/3}-type nuclear
enhancement can be calculated consistently in perturbative QCD. We derive the
transverse momentum broadening of the leading pions in deeply inelastic
lepton-nucleus collisions. We argue that the measurement of such transverse
momentum broadening can provide direct information on the multiple-parton
correlation functions inside a nucleus. We also estimate the numerical values
of the broadening at different values of x_B and Q^2.


title: Propagating Higgs Boundstates from Sfermions

abstract:
  A model of supersymmetric dynamical electroweak breaking with propagating
sfermionic Higgs boundstates is constructed. The low energy effective theory is
represented by a slight extension of the MSSM, including 2 additional Higgs
doublets and neutrino Yukawa couplings. A large tan(beta) is a necessary
condition. The model could be relevant in approaches which derive propagating
Higgs boundstates from strings.


title: Electroweak Radiative Corrections to W Boson Production at the Tevatron

abstract:
  We discuss the O(alpha) electroweak radiative corrections to W boson
production at the Tevatron and their effect on the W boson mass extracted by
experiment. The results of a new calculation of the O(alpha) corrections are
presented and compared with those of a previous calculation. We also briefly
discuss the O(alpha) corrections to Z boson production at the Tevatron and
two-photon radiation in W and Z events.


title: Chiral Multiplets of Large-N Ground State Baryons

abstract:
  I show that in the large-N limit the ground state baryons with helicity h
fall into an ((N-2h)/4,(N+2h)/4) irreducible representation of SU(2)XSU(2).
This representation determines the absolute normalization of the ground state
baryon axial vector couplings at large-N. Results map precisely to
(spin-flavor) SU(4) results. For instance, I find g_A =(N+2)/3. As a
consequence of this multiplet structure, chiral symmetry forbids pion
transitions between the ground state baryons and other baryon towers in the
large-N limit.


title:
Electroweak Penguins, Final State Interaction Phases and CP Violatioin
  in $B\to K \pi$ Decays

abstract:
  The recently observed $B^-\to K^- \pi^0$, $\bar K^0 \pi^-$ and $\bar B^0 \to
K^- \pi^+$ decay modes appear to have nearly equal branching ratios. This
suggests that tree and electroweak penguins play an important role, and
inclusion of the latter improves agreement between factorization calculation
and experimental data. The value $\gamma$ in the range $90^\circle -
130^\circle$ and $220^\circle - 260^\circle$ is favored, while the $\bar B^0
\to \bar K^0 \pi^0$ rate is suppressed. Direct CP violation for $B\to K \pi$
modes can be large if final state interaction phases are large.


title: Quasiparticles in Finite-Temperature Field Theory

abstract:
  Conventional finite-temperature perturbation theory in which propagators have
poles at $k^{2}=m^{2}$ is shown to break down at the two-loop level for
self-interacting scalar fields. The breakdown is avoided by using free thermal
propagators that have poles at the same energy as the exact thermal propagator.
This quasiparticle energy ${\cal E}(\vec{k})$ is temperature-dependent,
complex, and gauge invariant. An operator theory containing two self-adjoint
scalar fields is presented in which all temperature dependence is incorporated
into the Hamiltonian. No thermal traces are required to compute thermal Green
functions. Choosing the spectrum of the unperturbed part of the Hamiltonian to
contain the exact quasiparticle energy ${\cal E}(\vec{k})$ produces a resummed
perturbation theory that has the correct poles and branch cuts. The location of
the poles and cuts is explained directly in terms of the spectrum of the
Hamiltonian.


title: The $0^{++}$ and $0^{-+}$ mass of light-quark hybrid in QCD sum rules

abstract:
  We calculate masses of the light-quark hybrid mesons with the quantum number
$0^{++}$ and $0^{-+}$ by using the QCD sum rules. Two kinds of the interpolated
currents with the same quantum number are employed. We find that the
approximately equal mass is predicted for the $0^{-+}$ hybrid state from the
different current and the different mass is obtained for the $0^{++}$ hybrid
state from the different current. The prediction depends on the interaction
between the gluon and quarks in the low-lying hybrid mesons. The mixing effect
on the mass of the light-quark hybrid meson through Low-energy theorem has been
examined too, and it is found that this mixing shifts the mass of hybrid meson
and glueball a little.


title:
Large Strangeness as a QGP Signal in an Isentropic Quark-Hadron Phase
  Transition

abstract:
  Lattice QCD results reveal that the critical parameters and the order of the
quark-hadron phase transition are quite sensitive to the number of dynamical
flavours and their masses included in the theory. Motivated by this result we
develop a phenomenological equation of state for the quark-gluon plasma
consisting of $n_f$ flavours retaining the entropy per baryon ratio continuous
across the quark-hadron phase boundary. We thus obtain a generalised expression
for the temperature and baryon chemical potential dependent bag constant. The
results are shown for the realistic case, i.e., involving u, d and s quarks
only. We then obtain a phase boundary for an isentropic quark-hadron phase
transition using Gibbs' criteria. Similarly another phase boundary is obtained
for the transition to an ideal QGP from the solution of the condition
$B(\mu,T)=0$. The variation of critical temperature $T_c$ with the number of
flavours included in the theory. Also the variation of ${(\epsilon-4P)}/T^4$
with temperature are studied and compared with lattice results. Finally the
strange particle ratios $\frac{\bar{\Lambda}}{\Lambda}$,
$\frac{\bar{\Xi}}{\Xi}$ and $\frac{K^+}{K^-}$ are obtained at both phase
boundaries. We propose that their variations with the temperature and baryon
chemical potential can be used in identifying the quark-gluon plasma in the
recent as well as in future heavy-ion experiments.


title: Quark Mass Hierarchy, FCNC and CP violation in a Seesaw model

abstract:
  The seesaw model of quark masses is studied systematically, focusing on its
developments. A framework allowing the top quark mass to be of the order of the
electroweak symmetry breaking scale, while the remaining light quarks have much
smaller masses, due to the seesaw mechanism, is presented. The violation of the
GIM mechanism is shown to be small and the tree level FCNC are suppressed
naturally. In this model, there are many particles which could contribute to
the FCNC in the one-loop level. Parameters of the model are constrained by
using the experimental data on K^0-\bar{K}^0 mixing and \epsilon_K. The rare K
meson decays K_{L,S} -> \pi^0 \nu \bar{\nu} and K^+ -> \pi^+ \nu \bar{\nu} are
also investigated in the model. In these processes the scalar operators
(\bar{s}d)(\bar{\nu}_{\tau}\nu_{\tau}), which are derived from box diagrams in
the model, play an important role due to an enhancement factor M_K/m_s in the
matrix element <\pi|\bar{s}d|K>. It is emphasized that the K_L decay process
through the scalar operator is not the CP violating mode, so B(K_L -> \pi^0 \nu
\bar{\nu}) remains non-zero even in the CP conserved limit. The pion energy
spectra for these processes are predicted.


title:
Vortex tension as an order parameter in three-dimensional U(1)+Higgs
  theory

abstract:
  We use lattice Monte Carlo simulations to study non-perturbatively the
tension, i.e. the free energy per unit length, of an infinitely long vortex in
the three-dimensional U(1)+Higgs theory. This theory is the low-energy
effective theory of high-temperature scalar electrodynamics, the standard
framework for cosmic string studies. The vortex tension is measured as a
function of the mass parameter at a large value of the Higgs self-coupling,
where the transition between the phases is continuous. It is shown that the
tension gives an order parameter that can distinguish between the two phases of
the system. We argue that the vortex tension can describe the physics of long
strings without lattice artifacts, unlike vortex network percolation.


title: First principle qqbar Salpeter equation, spectrum and Regge trajectories

abstract:
  Starting from a first principle Salpeter equation we computed the
heavy-heavy, light-light and heavy-light quarkonium spectrum and the ground
light-light Regge trajectories. We neglect spin-orbit structures and exclude
from our treatment the light pseudoscalar states which in principle would
require the use of the full Bethe-Salpeter equation due to the chiral symmetry
breaking problem. We found a good agreement with the experimental meson masses
and straight Regge trajectories with the right slope and intercepts. Since the
parameter are completely specified by the heavy quarkonium spectrum and by high
energy scattering, for what concerns light-light and light-heavy quarkonium
systems our calculation is essentially parameter free.


title:
Feasibility of search for nuclear electric dipole moments at ion storage
  rings

abstract:
  The sensitivity much better than $10^{-24} e$ cm may be expected in the
searches for electric dipole moments (EDM) of $\beta$-active nuclei at ion
storage rings. It would be a serious progress in studies of the CP-violation
problem.

categories: hep-ph nucl-th physics.acc-ph physics.atom-ph


title: N/D Description of Two Meson Amplitudes and Chiral Symmetry

abstract:
  The most general structure of an elastic partial wave amplitude when the
unphysical cuts are neglected is deduced in terms of the N/D method. This
result is then matched to lowest order, ${\mathcal{O}}(p^2)$, Chiral
Perturbation Theory($\chi$PT) and to the exchange (consistent with chiral
symmetry) of resonances in the s-channel. The extension of the method to
coupled channels is also given. Making use of the former formalism, the
$\pi\pi$ and $K\pi$(I=1/2) P-wave scattering amplitudes are described without
free parameters when taking into account relations coming from the 1/$N_c$
expansion and unitarity. Next, the scalar sector is studied and good agreement
with experiment up to $\sqrt{s}=1.4$ GeV is found. It is observed that the
$a_0(980)$, $\sigma$ and $\kappa(900)$ resonances are meson-meson states
originating from the unitarization of the ${\mathcal{O}}(p^2)$ $\chi$PT
amplitudes. On the other hand, the $f_0(980)$ is a combination of a strong
S-wave meson-meson unitarity effect and of a preexisting singlet resonance with
a mass around 1 GeV. We have also studied the size of the contributions of the
unphysical cuts to the $\pi\pi$(I=0) and $K\pi$(I=1/2) elastic S-wave
amplitudes from $\chi$PT and the exchange of resonances in crossed channels up
to $\sqrt{s}\approx 800$ MeV. The loops are calculated as in $\chi$PT at next
to leading order. We find a small correction from the unphysical cuts to our
calculated partial waves.


title: Determination of the strange-quark mass from QCD pseudoscalar sum rules

abstract:
  A new determination of the strange-quark mass is discussed, based on the
two-point function involving the axial-vector current divergences. This Green
function is known in perturbative QCD up to order O(alpha_s^3), and up to
dimension-six in the non-perturbative domain. The hadronic spectral function is
parametrized in terms of the kaon pole, followed by its two radial excitations,
and normalized at threshold according to conventional chiral-symmetry. The
result of a Laplace transform QCD sum rule analysis of this two-point function
is: m_s(1 GeV^2) = 155 pm 25 MeV.


title:
The Classical Approximation for Real-Time Scalar Field Theory at Finite
  Temperature

abstract:
  The use of classical thermal field to approximate real-time quantum thermal
field theory is discussed. For a \lambda\phi^4 theory, it is shown that the
classical Rayleigh-Jeans divergence can be canceled with the appropriate
counterterms, and a comparison is made between the classical and quantum
perturbative expansion. It is explained why Hard Thermal Loops prevent the same
method to work for gauge theories.


title: Non-Equilibrium Dynamics with Fermions on a Lattice in Space and Time

abstract:
  We consider the dynamics of the 1+1 dimensional abelian Higgs model with
axially coupled fermions, in the large N_f limit, on a lattice in space and
real-time. We allow for inhomogeneous classical Bose fields. In order to deal
with the lattice doublers, we use Wilson's lattice fermions. The lattice
formulation leads to a stable integration algorithm. We demonstrate the
practical implementation with numerical results.


title: Positronium hyperfine splitting: analytical value at m*alpha^6

abstract:
  We present an analytic calculation of the m*alpha^6 recoil corrections to the
hyperfine splitting (HFS) of the ground state energy levels in positronium. We
find \Delta E_{\rm rec} = m alpha^6 (-1/6 ln(alpha) + 331/432 -ln(2)/4 - 17
Zeta(3)/(8 pi^2) + 5/(12 pi^2)) \approx m alpha^6 (- 1/6 ln(alpha) + 0.37632),
confirming Pachucki's numerical result \cite{Ph}. We present a complete
analytic formula for the m*alpha^6 HFS of the positronium ground state and,
including m*alpha^7*ln^2(alpha) effects, find E(1^3S_1)-E(1^1S_0))_{theory} =
203 392(1) MHz. This differs from the experimental results by about 3 standard
deviations.


title: Chiral Lagrangians out of thermal equilibrium

abstract:
  We extend Chiral Perturbation Theory to study a meson gas out of thermal
equilibrium. We assume that the system is initially in equilibrium at a
temperature below the phase transition and work within a Schwinger-Keldysh
contour technique. To lowest order and in the chiral limit, our model is a
nonlinear sigma model with a time-dependent pion decay function (PDF), which we
consistently define in terms of the axial current two-point correlator. As a
first application, we analyse the PDF up to one loop and find the initial
temperature dependence of the lowest order coefficients in the short-time
expansion. We discuss the applicability of our approach to the time evolution
of the plasma formed after a RHIC and discuss the interpretation of our model
in a curved space-time background context.


title: Light Rays of New Physics: CP Violation in B -> Xs gamma Decays

abstract:
  The observation of a sizable CP asymmetry in the inclusive decays B -> Xs
gamma would be a clean signal of New Physics. In the Standard Model, this
asymmetry is below 1 % in magnitude. In extensions of the Standard Model with
new CP-violating couplings, large asymmetries are possible without conflicting
with the experimental value of the B -> Xs gamma branching ratio. In
particular, large asymmetries arise naturally in models with enhanced
chromo-magnetic dipole transitions. Some generic examples of such models are
explored and their implications for the semileptonic branching ratio and charm
yield in B decays discussed.


title: A Parametrisation of the Inclusive Diffractive Cross Section at HERA

abstract:
  A recently proposed parametrization for the deep inelastic diffractive cross
section is used to describe the H1 94 data. We find two possible solutions, and
we discuss them is some detail.


title:
Doublet-Triplet Splitting in Supersymmetric SU(6) by Missing VEV
  Mechanism

abstract:
  We present a realistic supersymmetric SU(6) model which implements
doublet-triplet splitting by the missing vev mechanism. The model makes use of
only the simplest representations, requires no fine tuning of parameters and
maintains coupling constant unification as a prediction. Fermion masses also
emerge in a very straightforward manner. This is the first time that the
missing vev mechanism has been realized in the context of SU(6).


title:
Dynamical renormalization group resummation of finite temperature
  infrared divergences

abstract:
  We introduce the method of dynamical renormalization group to study
relaxation and damping out of equilibrium directly in real time and applied it
to the study of infrared divergences in scalar QED. This method allows a
consistent resummation of infrared effects associated with the exchange of
quasistatic transverse photons and leads to anomalous logarithmic relaxation of
the form $e^{-\alpha T t \ln[t/t_0]}$ which prevents a quasiparticle
interpretation of charged collective excitations at finite temperature. The
hard thermal loop resummation program is incorporated consistently into the
dynamical renormalization group yielding a picture of relaxation and damping
phenomena in a plasma in real time that trascends the conceptual limitations of
the quasiparticle picture and other type of resummation schemes. We derive a
simple criterion for establishing the validity of the quasiparticle picture to
lowest order.


title: A useful approximate isospin equality for charmless strange B Decays

abstract:
  A useful inequality is obtained if charmless strange B decays are assumed to
be dominated by the gluonic penguin diagram and the tree diagram contribution
is small but not negligible. The penguin-tree interference contribution which
is linear in the tree amplitude is included but the direct tree contribution
which is quadratic is neglected.


title: Do neutrinos have mass only within matter?

abstract:
  We look at the possibility that appreciable neutrino masses and flavor mixing
occur only within material media, driven by an interaction between leptons and
a very light scalar particle. Limits are placed on the scalar particle mass and
coupling constants from a number of experimental and astrophysical
considerations.


title: Covariant Wave Function Reduction and Coherent Decays of Kaon Pair

abstract:
  The recently developed relativistically covariant formulation of wave
function reduction is illustrated for Lipkin's proposal to study CP violation
in the coherent decay of kaon pairs. Covariant results are obtained in
agreement with an amplitude approach proposed in the literature.


title:
NLO corrections to Delta F=2 effective Hamiltonians and SUSY
  contribution to FCNC

abstract:
  The most general QCD-NLO Anomalous-Dimension Matrix of all four-fermion
dimension six Delta F=2 operators is presented. Two applications of this
Anomalous-Dimension Matrix to the study of SUSY contribution to K- Kbar mixing
are also discussed.


title: The Mechanism of Quark Confinement

abstract:
  I summarise recent lattice results on the QCD confinement mechanism in the
maximally Abelian projection.


title: Status of the Standard Model

abstract:
  We review the experimental and theoretical status of the standard electroweak
theory, and its fundamental parameters. We obtain the global best fit result
for the Standard Model Higgs boson of M_H = 107^{+67}_{-45} GeV, and find the
95% upper limit of 255 GeV. Parameters describing physics beyond the Standard
Model are discussed as well. Particular emphasis is given to implications for
supersymmetric extensions of the Standard Model.


title:
Impact of Light Higgs Properties on the Determination of $\tan\beta$ and
  $m_{susy}$

abstract:
  We examine whether parameters related to the Higgs sector of the minimal
supersymmetric standard model can be determined by detailed study of the
production cross section and decay branching ratios of the Higgs boson.
Assuming that only the light Higgs boson will be observed at a future $e^+e^-$
linear collider with $\sqrt{s}=300\sim500$ GeV, we show that values of
$m_{susy}$ and $\tan\beta$ are restricted within a narrow region in the
$m_{susy}$ versus $\tan\beta$ plane by the combined analysis of the light Higgs
properties. It is also pointed out that, in some case, $\tan\beta$ may be
restricted to a relatively small value, $\tan\beta=1\sim5$.


title: Constraining four generation SM with b\to s \gamma and b\to s g decays

abstract:
  Using the experimental result on b\to s\gamma and theoretical result on b\to
sg, a four -generation SM is analysed to constrain the rephasing-invariant
combinations of the CKM matrix and masses of the fourth generation quarks.


title:
e^+e^-\to (h A)\to bbbb in Abelian Extended Supersymmetric Standard
  Model

abstract:
  We discuss the $e^{+}e^{-}\to (h A)\to bbbb$ cross section in an Abelian
extended SM. We work in that minimum of the scalar potential for which Higgs
trilier coupling is greater than the soft mass parameters. We find that
nex-to-lightest Higgs gives the essential contribution to the cross section in
the small $Z-Z'$ mixing angle and leptophobic $Z'$ limit.


title: Higgs-strahlung in Abelian Extended Supersymmetric Standard Model

abstract:
  We analyze the Higgs production via the Higgs-strahlung process
$e^{+}e^{-}\to h_{k}{\it{l}}^{+}{\it{l}}^{-}$ in an Abelian Extended
Supersymmetric SM. We work in the large Higgs trilinear coupling driven minimum
of the potential, and find that the next-to-lightest Higgs cannot be produced
by this process. Other Higgs scalars, namely the lightest and the heaviest,
have cross sections comparable to that in the pure SM. It is found that the
present model has observable differences with the other popular model, NMSSM,
in the same type of minimum.


title: One-Loop Effects in Supergravity Models with an Additional U(1)

abstract:
  For an Abelian extended Supergravity model, we investigate some important low
energy parameters: \tan\beta, Z-Z' mixing angle, lightest CP-even Higgs mass
bound, Z' mass, and effective \mu parameter. By integrating the RGE's from
string scale down to the weak scale we constuct the scalar potential, and
analyze the quantities above at the tree- and one-loop levels by including the
contributions of top squarks and top quark in the effective potential. PACS:
04.65.+e, 12.60.Jv


title: Two-Higgs doublet models from TeV-scale supersymmetric extra U(1) models

abstract:
  We investigate the reduction of a general TeV-scale supersymmetric extra U(1)
model to a 2HDM below the TeV- scale through the tree level non-decoupling.
Portions of the parameter space of the extra U(1) model appropriate for
obtaining a 2HDM are identified. Various properties of the resulting 2HDM are
connected to the parameter space of the underlying model. PACS: 12.60.Jv,
12.60.Cn, 12.60.Fr


title: gg\to \gamma \bar{f}f in the strongly interacting phase of the MSSM

abstract:
  g g \to \gamma \bar{f}f scattering is discussed in the strongly interacting
phase of the MSSM. The rate for the decay h \to \gamma \bar{f} f is computed in
the MSSM and SM, and values of the Higgs-sfermion coupling needed for the
former to dominate on the latter are identified. It is found that the MSSM
signal dominates on the SM one for Higgs-sfermion couplings well below the one
needed for developing stopponium bound states via Higgs mediation.


title: Probing the phases in the MSSM via e^+ e^- \to h A

abstract:
  In the presence of the supersymmetric CP phases, e^+ e^- \to Z^{*} \to h A
scattering is analyzed, with special emphasis on Z^{*} h A vertex, taking into
account radiatve corrections due to dominant top quark and top squark loops in
the Higgs sector as well as the vertex formfactors. It is found that the
lightest Higgs remains essentially CP-even whereas the heavier ones mix with
each other strongly. Moreover, the supersymmetric CP phases are found to create
tree-level couplings between a pseudoscalar and identical sfermion mass
eigenstates which, together with the radiative corrections in the Higgs sector,
are found to enhance the vertex formfactors significantly.


title: Implications of \Delta \rho and CHARM II data for Z' Physics

abstract:
  We discuss the constraints on the Z' model parameters coming from Z- pole and
low-energy \nu_{\mu}-e scattering data in the frame work of GUT- motivated
models. We find that when the coupling constant of the extra U(1) is small
(large) the parameter space is mainly determined by the Z-pole (the low-energy
\nu_{\mu}-e scattering) data.


title: The Dynamics of Quarkonium Production

abstract:
  Quarkonium production is a sensitive probe of the dynamics of hard
scattering, which can `measure' the environment of the heavy quark pair after
it is created in a hard process. Quarkonium hadroproduction data indicates that
the produced pair experiences a secondary, hard interaction and then ceases to
interact at a stage when the pair is still compact (compared to the size of the
quarkonium wave function). These features differ from scenarios mostly
discussed so far. An approach which relies on an early, perturbative
rescattering of the pair with a comoving color field can explain many observed
features, including the polarization, the $\chi_1/\chi_2$ ratio and the nuclear
target $A$-dependence, which are difficult to understand otherwise.


title: Relic neutrino asymmetry evolution from first principles

abstract:
  The exact Quantum Kinetic Equations for a two-flavour active-sterile neutrino
system are used to provide a systematic derivation of approximate evolution
equations for the relic neutrino asymmetry. An extension of the adiabatic
approximation for matter-affected neutrino oscillations is developed which
incorporates decoherence due to collisions. Exact and approximate expressions
for the decoherence and repopulation functions are discussed. A first pass is
made over the exact treatment of multi-flavour partially incoherent
oscillations.


title: Charmless Hadronic Two-body Decays of the B_s Mesons

abstract:
  Two-body charmless nonleptonic decays of the B_s meson are studied within the
framework of generalized factorization in which factorization is applied to the
tree level matrix elements while the effective Wilson coefficients are $\mu$
and renormalization scheme independent, and nonfactorizable effects are
parametrized in terms of N_c(LL) and N_c(LR), the effective numbers of colors
arising from (V-A)(V-A) and (V-A)(V+A) four-quark operators, respectively.
Branching ratios of $B_s\to PP,PV,VV$ decays are calculated as a function of
N_c(LR) with two different considerations for N_c(LL). We find that (i) the
electroweak penguin contributions account for about 85% (for N_c(LL)=2) of the
decay rates of $B_s\to \eta\pi,\eta'\pi,\eta\rho,\eta'\rho,\phi\pi,\phi\rho$,
which receive contributions only from tree and electroweak penguin diagrams; a
measurement of them will provide a clean determination of the electroweak
penguin coefficient a_9, (ii) electroweak penguin corrections to $B_s\to\omega
\etapp,\phi\eta,\omega\phi,K^{(*)}\phi,\phi\phi$ are in general as significant
as QCD penguin effects and even play a dominant role; their decay rates depend
strongly on N_c(LR), (iii) the branching ratio of $B_s\to \eta\eta'$ is of
order 2x10^{-5}, (iv) the contribution from the $\eta'$ charm content is
important for $B_s\to\eta'\eta'$, but less significant for $B_s\to\eta\eta'$,
and (v) the decay rates for the final states $K^{+(*)}K^{-(*)}$ follow the
pattern: $\Gamma(B_s\to K^+K^-)>\Gamma(B_s\to K^+K^{*-})\geq\Gamma(B_s\to
K^{*+}K^{*-}) >\Gamma(B_s\to K^{+*}K^-)$, as a consequence of various
interference effects between the penguin amplitudes governed by the
coefficients a_4 and a_6.


title: Electroweak baryogenesis induced by a scalar field

abstract:
  A cosmological pseudoscalar field coupled to hypercharge topological number
density can exponentially amplify hyperelectric and hypermagnetic fields while
coherently rolling or oscillating, leading to the formation of a time-dependent
condensate of topological number density. The topological condensate can be
converted, under certain conditions, into baryons in sufficient quantity to
explain the observed baryon asymmetry in the universe. The amplified
hypermagnetic field can perhaps sufficiently strengthen the electroweak phase
transition, and by doing so, save any pre-existing baryon number asymmetry from
extinction.


title: R-Invariant Dilaton Fixing

abstract:
  We consider dilaton stabilization with R invariance, which insures a
vanishing cosmological constant at the scale of stabilization. We construct a
few models which accommodate weak gauge couplings with large or small gauge
groups. Matter condensation plays a central role in the dilaton stabilization.


title:
Problems in the resummation of soft-gluon effects in the
  transverse-momentum distributions of massive vector bosons in hadronic
  collisions

abstract:
  We consider the resummation of soft-gluon emission in the transverse-momentum
distribution of vector mesons in hadronic collisions. We find that the resummed
expression in the impact-parameter formulation has an expansion in $\as$ with
factorially growing terms with oscillating signs. These diverging terms arise
from the small impact-parameter region of integration, and are of a subleading
nature. We also obtain a closed expression for the next-to-leading logarithm
resummation in $\qt$-space, and we study its analytic structure. We find in
this case that, although no factorially growing terms are present, there are
geometrical singularities that severely restrict the range of applicability of
the resummation formula.


title: On the neutrino mass spectrum and neutrino mixing from oscillation data

abstract:
  Two schemes of mixing of four massive neutrinos with two couples of close
neutrino masses separated by a gap of the order of 1 eV can accommodate solar,
atmospheric and LSND neutrino oscillation data. It is shown that long-baseline
nu(e)->nu(e) and nu(mu)->nu(e) transitions are strongly suppressed in these
schemes. The scheme of mixing of three neutrino masses with a mass hierarchy
that can describe solar and atmospheric neutrino data is also discussed. It is
shown that in this scheme the effective Majorana mass |<m>| that characterizes
the matrix element of neutrinoless double-beta decay is less than 10^{-2} eV.


title:
Analytically integrated results for heavy fermion production in
  two-photon collisions and a high precision $\alpha_s$ determination

abstract:
  The cross section for massive fermion production in two-photon collisions was
examined at next-to-leading order in QCD/QED for general photon helicity. The
delta function (virtual+soft) part of the differential cross section was
analytically integrated over the final state phase space. Series expansions for
the complete differential and total cross sections were given up to tenth order
in the parameter $\beta$. These were shown to be of practical use and revealed
much structure. Accurate parametrizations of the total cross sections were
given, valid up to higher energies. The above results were applied to top quark
production in the region not too far above threshold. The cross section was
shown to be quite sensitive to $\alpha_s$ in the appropriate energy region.


title:
Lepton Number and Lepton Flavour Violation in Left-Right Symmetric
  Models

abstract:
  The sources of lepton flavour and lepton number violation in the left-right
symmetric models are reviewed and the most sensitive processes to these
violations are discussed. Both the non-SUSY and SUSY versions of the theories
are considered. Present and future experimental constraints at low as well as
at high energies are discussed. Some emphasis has been put on the doubly
charged particle production at future colliders.


title:
Possible Effects of Quantum Mechanics Violation Induced by Certain
  Quantum Gravity on Neutrino Oscillations

abstract:
  In this work we tried extensively to apply the EHNS postulation about the
quantum mechanics violation effects induced by the quantum gravity of black
holes to neutrino oscillations. The possibilities for observing such effects in
the neutrino experiments (in progress and/or accessible in the near future)
were discussed. Of them, an interesting one was outlined specially.


title:
Semileptonic and Rare $B$-meson transitions in a QCD relativistic
  potential model

abstract:
  Using a QCD relativistic potential model, previously applied to the
calculation of the heavy meson leptonic constants, we evaluate the form factors
governing the exclusive decays $B\to\rho\ell\nu$, $B\to K^*\gamma$ and $B\to
K^*\ell^+\ell^-$. In our approach the heavy meson is described as a $Q\bar q$
bound state, whose wave function is solution of the relativistic Salpeter
equation, with an instantaneous potential displaying Coulombic behaviour at
small distances and linear behaviour at large distances. The light vector meson
is described by using a vector current interpolating field, according to the
Vector Meson Dominance assumption. A Pauli-Villars regularized propagator is
assumed for the quarks not constituting the heavy meson. Our procedure allows
to avoid the description of the light meson in terms of wave function and
constituent quarks, and consequently the problem of boosting the light meson
wave function.
  Assuming as an input the experimental results on $B\to K^*\gamma$, we
evaluate all the form factors describing the $B\to \rho, K^*$ semileptonic and
rare transitions. The overall comparison with the data, whenever available, is
satisfactory.


title: Future Diffraction at HERA

abstract:
  Future prospects of hard diffraction at HERA a reviewed. A selection of
processes which can be calculated in pQCD is given, with emphasis on the
separation of soft and hard diffraction. The main focus will be put on the
energy dependence of diffractive processes and signatures for the hard pQCD
pomeron. Problems in the experimental detection of these processes and the
expected significance of future measurements at HERA are discussed.


title: Monte Carlo Implementations of Diffraction at HERA

abstract:
  The Monte Carlo implementation of different approaches for diffractive
scattering in $e - p$ collisions (resolved $\PO$, pQCD, soft color
interactions) is described, with emphasis on the construction of the hadronic
final state. Simple models for proton dissociation and exclusive vector meson
production are described. A comparison of the different approaches is given.


title: Dark Matter from Unstable B-balls

abstract:
  The spectrum of MSSM admits solitons carrying baryonic charge, or B-balls. In
an inflationary universe they can be produced in significant numbers by a
break-up of a scalar condensate along the flat directions. It is shown that if
SUSY breaking is mediated to the observable sector by gravity, B-balls are
unstable but decay to baryons and LSPs typically well below the electroweak
phase transition. It is argued that B-balls could be the source of most baryons
and cold dark matter in the universe, with their number densities related by
$n_{LSP}\simeq 3n_{B}$. For B-balls to survive thermalization, the reheating
temperature after inflation should be less than about $10^{3}$ GeV.


title: Neutrino Conversions in Solar Random Magnetic Fields

abstract:
  We consider the effect of a random magnetic field in the convective zone of
the Sun superimposed to a regular magnetic field on resonant neutrino
spin-flavour oscillations. We argue for the existence of a field of strongly
chaotic nature at the bottom of the convective zone. In contrast to previous
attempts we employ in addition a model motivated regular twisting magnetic
field profile. In this scenario electron antineutrinos are produced through
cascades like $\nu_{eL}\to \nu_{\mu L}\to \tilde{\nu}_{eR}$, The expected
signals in the different experiments (SK,GALLEX-SAGE, Homestake) are obtained
as a function of the level of noise, regular magnetic field and neutrino mixing
parameters. Previous results obtained for small mixing and ad-hoc regular
magnetic profiles are reobtained. We confirm the strong suppression for large
part of the parameter space of the $\tilde{\nu}_{eR}$-flux for high energy
boron neutrinos in agreement with present data of the SK experiment. We find
that MSW regions ($\Delta m^2\approx 10^{-5}$ eV$^2$, both small and large
mixing solutions) are stable up to very large levels of noise (P=0.7-0.8) but
they are acceptable from the point of view of antineutrino production only for
moderate levels of it ($P\approx 0.95$). For strong noise and reasonable
regular magnetic field, any parameter region $(\Delta m^2, \sin^2 2\theta)$ is
excluded. As a consequence, we are allowed to reverse the problem and to put
limits on r.m.s field strength and transition magnetic moments by demanding a
particle physics solution to the SNP under this scenario.


title: Theoretical Status of B -> Xs gamma Decays

abstract:
  We review the theoretical understanding of the branching ratio and
photon-energy spectrum in B -> Xs gamma decays at next-to-leading order in QCD,
including consistently the effects of Fermi motion. For the Standard Model, we
obtain B(B -> Xs gamma)=(3.29 +- 0.33)*10^{-4} for the total branching ratio,
and B(B -> Xs gamma)=(2.85+0.34-0.40)*10^{-4} if a cut E_gamma > 2.1 GeV is
applied on the photon energy, as done in the recent CLEO analysis. A precise
measurement of the photon spectrum would help reducing the theoretical
uncertainty and yield important information on the momentum distribution of b
quarks inside B mesons.


title: Real-Time Dimensional Reduction in Thermal Field Theory

abstract:
  We consider the extension of static dimensional reduction to real-time. For a
scalar field theory it is shown that in the high-temperature limit this leads
to an effective classical theory. Quantum corrections to the leading classical
behavior are determined by an effective action which can be calculated
perturbatively in the background of the classical fields. Feynman rules for
(\lambda\phi^4)-theory are given and the extension to SU($N$) gauge theories is
outlined.


title: Quasiparticle description of strongly coupled plasmas

abstract:
  The extrapolation of truncated perturbative series to the large coupling
regime is not reliable since the accuracy of the calculations cannot be
improved systematically by a finite set of higher order terms. Instead, a
nonperturbative approach is proposed here to describe the thermodynamics of
strongly coupled plasmas. Within the $\phi^4$ theory, it is derived from the
Luttinger-Ward theorem and amounts to a quasiparticle description. The approach
is extended to the quark-gluon plasma. Even close to the confinement
temperature it is found to be in a good agreement with lattice data of several
gauge systems. The model is applied to predict the equation of state of the
quark-gluon plasma with realistic quark masses.


title: Quasi-real photon production in thermal QCD

abstract:
  In this proceedings, I consider two-loop contributions to real photon
production in thermal QCD. If the photon is strictly massless, strong collinear
divergences appear in this calculation. These singularities are regularized by
the quark thermal mass of order $gT$, which generates powers of $1/g$, so that
the corresponding terms are strongly enhanced with respect to naive
expectations of their order of magnitude.


title: Baryon Asymmetry and Dark Matter

abstract:
  We study the implications of a large baryogenesis temperature, $T_B =
O(10^{10}$ GeV), on the mass spectrum of superparticles in supersymmetric
extensions of the standard model. Models with a neutralino as lightest
superparticle (LSP) are excluded. A consistent picture is obtained with the
gravitino as LSP, followed by a higgsino-like neutralino (NSP). Gravitinos with
masses from 10 to 100 GeV may be the dominant component of dark matter.


title: Dimensional Reduction in High Temperature Gauge Theories

abstract:
  Screening masses in the equilibrium thermodynamics of gauge theories were
measured. The spectroscopy of these screening masses gives strong evidence for
dimensional reduction at $T\ge2T_c$. A perturbative explanation of these masses
is ruled out. The mass ratios in the high temperature phase are consistent with
those in the pure gauge theory in three dimensions.


title: Thermal effective potential of the linear sigma model

abstract:
  We have attempted an approach to the chiral phase transition of QCD using the
linear sigma model as an effective theory. In order to get some insight into
how the phase transition could proceed, we have calculated the finite
temperature effective potential of this model in the Hartree and large N
approximations using the Cornwall-Jackiw-Tomboulis formalism of composite
operators.


title: Combining CP Asymmetries in $B \to K \pi$ Decays

abstract:
  We prove an approximate relation, to leading order in dominant terms, between
CP-violating rate differences in $B^0/\bar{B}^0 \to K^{\pm}\pi^{\mp}$ and
$B^{\pm} \to K^{\pm}\pi^0$. We show how data from these two processes may be
combined in order to enhance the significance of a nonzero result.


title: Hadronization of massive quark matter

abstract:
  We present a fast hadronization model for the constituent quark plasma (CQP)
produced in relativistic heavy ion collisions at SPS. The model is based on
rate equations and on an equation of state inspired by the string
phenomenology. This equation of state has a confining character. We display the
time evolution of the relevant physical quantities during the hadronization
process and the final hadron multiplicities. The results indicate that the
hadronization of CQP is fast.


title: CP Violation in Two-Body Hadronic Decays of $B_c$ Meson

abstract:
  Using the next-to-leading order low energy effective Hamiltonian, the CP
asymmetries for the $B_{c}$ meson decays into meson pair are calculated in the
spectator approximation. We do not compute the hadronic matrix elements
directly, instead, we use the amplitude ratios to estimate the CP asymmetries.
This is quite,different from the previous works in the literature. The values
of the momentum squared carried by the virtual particles in timelike penguin
dirgrams are also carefully discussed. From our calculated results, the best
decay modes to observe CP violation in $B_{c}$ decays would be $B_{c}^-\to{\bar
D}^{*0}K^{*-}$, ${\bar D}^{0}K^{*-}$, ${\bar D}^{*0} K^{-}$, ${\bar
D}^{0}K^{-}$ and $B_{c}^-\to{\eta}_{c}D^{-}$, which need about $10^8$ of
$B_{c}^{\pm}$ events in experiment.


title: Closing in on B-CP

abstract:
  Major new experimental efforts on detecting CP violation in $B$ decays will
very soon go on the air. Recent developments suggest that final state
interaction phases in exclusive decays of $B$ are unlikely to be small
indicating the possibility of observable direct CP asymmetries in these
channels. CLEO results on charmless hadronic modes suggest penguin amplitudes
are rather big implying that the extraction of $\alpha$ from $B^0$-$\bar B^0$
alone will be difficult, thus necessitating also information from direct
CP\null. Importance of $B(B_s)$ decays to two vectors for model independent
tests of electroweak penguins and for extraction of $\alpha(\gamma)$ is
emphasized. Inclusive $b\to sg^\ast$ and related modes, e.g. $B\to \eta^\prime
X_s$, are very good probes of CP-odd phase(s) due to beyond the standard model
physics. On the other hand, $b\to dg^\ast$ and related modes, e.g. $B\to
\eta^\prime X_d$ are more suitable for CP violation due to the CKM phase. Two
body $b$-quark decays: $b\to Mq_f$ leading to semi-inclusive, $B$ decays, $B\to
MX$ (with $2\lsim E_M\lsim2.8$ GeV), are very interesting and important. Their
theory is relatively clean; partial rate asymmetries may be large in several
cases (e.g. $M=K^\ast, K, \rho, \pi...$) and a few cases provide very good
probe of electroweak penguins.


title: Hyperon Non-leptonic Weak Decays in the Chiral Perturbation Theory I

abstract:
  Hyperon non-leptonic weak decay amplitudes are studied in the chiral
perturbation theory. We employ the low energy effective weak Hamiltonian which
contains the perturbative QCD correction. To include the non-perturbative QCD
effect, quark currents of the effective Hamiltonian are substituted with
hadronic currents which are color singlet and are derived by the chiral
perturbation theory. We find that the amplitudes caused by the product of
hadronic currents are small. It reproduce the small amplitudes of $\Delta
I=3/2$, which are derived by the strong interaction correction.


title: Scalar meson exchange and the baryon spectra

abstract:
  We explore the role of a scalar meson exchange interaction between quarks in
a semirelativistic constituent quark model where the quarks are subject to a
linear confinement. We search for a variational solution and show that the gap
between the N=1 band and the ground state N=0 band increases with the strength
of the scalar meson exchange interaction potential. This result has good
implications on the description of the low-lying baryon resonances, especially
on the Roper vs. negative parity resonances ordering.


title: Critical Slowing Down from $T\neq 0$ Wilson RG

abstract:
  The Thermal Renormalization Group can be employed to study the dynamics of
$T\neq 0$ Quantum Field Theories close to second order phase transitions, where
neither resummed perturbation theory nor first principle lattice simulations
can be employed. As an example, I discuss the computation of the plasmon
damping rate in the scalar field theory from $T\gg T_C$ down to $T_C$. As the
critical point is approached, the lifetime of long wavelength thermal
fluctuations diverges. Taking this effect into account, the notion of
quasiparticle, and kinetic approaches, can be extended close to the critical
regime. The consequences on the scenarios for topological defect formation in
the early universe are also discussed.


title: A new approach to parton recombination in a QCD evolution equation

abstract:
  Parton recombination is reconsidered in perturbation theory without using the
AGK cutting rules in the leading order of the recombination. We use
time-ordered perturbation theory to sum the cut diagrams, which are neglected
in the GLR evolution equation. We present a set of new evolution equations
including parton recombination.


title:
Effective Theories for Exclusive and Seminclusive Processes and
  Factorization

abstract:
  The effective theories for massless quarks describing exclusive and
seminclusive processes are discussed, considering in particular the
factorization problem.


title: A Constituent Quark-Meson Model for Heavy Meson Decays

abstract:
  I describe a model for heavy meson decays based on an effective quark-meson
lagrangian. I consider the heavy mesons S with spin and parity J^P=(1+,0+), H
with J^P=(1-,0-) and T^mu with J^P=(2+,1+), i.e. S and P wave heavy-light
mesons. The model is constrained by the known symmetries of QCD in the mQ ->
infinity limit for the heavy quarks, and chiral symmetry in the light quark
sector. Using a very limited number of free parameters it is possible to
compute several phenomenological quantities, e.g. the leptonic B and B** decay
constants; the three universal Isgur-Wise form factors: xi, tau(3/2), tau(1/2),
describing the semi-leptonic decays B -> D(*) l nu, B -> D** l nu; the strong
and radiative D* decays; the weak semi-leptonic decays of B and D into light
mesons: pi, rho, a1. An overall agreement with data, when available, is
achieved.


title: Strangeness, charm and bottom in a chiral quark-meson model

abstract:
  In this paper we investigate an SU(3) extension of the chiral quark-meson
model. The spectra of baryons with strangeness, charm and bottom are considered
within a "rigid oscillator" version of this model. The similarity between the
quark part of the Lagrangian in the model and the Wess-Zumino term in the
Skyrme model is noted. The binding energies of baryonic systems with baryon
number B=2 and 3 possessing strangeness or heavy flavor are estimated. The
results obtained are in good qualitative agreement with those obtained
previously in the topological soliton (Skyrme) model.


title:
Cancellation of pinching singularities in out-of-equilibrium thermal
  field theory

abstract:
  Long standing problem in out-of-equilibrium thermal field theories are
pinching singularities. We find that the expressions suspect of pinching
require loop particles to be on the mass shell. This fact, with the help of
threshold effect and similar effect due to spin, leads to the elimination of
pinching in single self-energy insertion approximation to propagator in all
propagators appearing in QED and QCD under very mild restrictions on particle
densities.
  This, together with the cancellation of collinear singularities, allows the
extraction of useful physical information contained in the imaginary parts of
the two loop diagrams.
  In some cases of interest ($\pi-\rho $ interaction, electro-weak interaction,
decay of Higgs particle, ...) none of the mentioned mechanisms works and one
has to resort to the resummed Schwinger-Dyson series. These cases are more
sensitive to the limitations related to the finite time range.


title:
Test of Special Relativity and Equivalence Principle from Neutrinoless
  Double Beta Decay

abstract:
  We generalize the formalism for testing Lorentz invariance and the
equivalence principle in the neutrino sector. While neutrino oscillation bounds
constrain the region of large mixing of the the weak and gravitational
eigenstates, we obtain new constraints on violations of Lorentz invariance and
the equivalence principle from neutrinoless double beta decay. These bounds
apply even in the case of no mixing and thus probe a totally unconstrained
region in the parameter space.


title: Isolated photons without fragmentation contribution

abstract:
  I illustrate how to define an isolated-photon cross section which is
independent of the parton-to-photon fragmentation contribution, it is infrared
safe to all orders in perturbative QCD, and it is exclusive in the kinematical
variables of the photon and of the accompanying jets. This isolation
prescription is applicable to any kind of polarized or unpolarized hard
collisions. It can also be used without any modifications in the case of two or
more isolated photons in the final state. I present results for one-photon
production in hadronic collisions, and I compare them with existing results
obtained in the framework of the conventional cone approach.


title: On the polarization of the nucleon sea in the meson cloud model

abstract:
  It is pointed out that the meson cloud model predicts a substantial
polarization of the sea quarks of the nucleon due to interference of $\pi$ and
$\rho$ exchanges. This polarization is strongly flavour dependent. The model
gives an explanation of a strong increase in the structure function $g_1$ with
isospin I=1 at small $x$.


title: Experimental Prospects for CP Violation in Charm

abstract:
  Experimental sensitivity to CP violation in charm decay is beginning to
approach the interesting regime ($\sim10^{-3}$) in which new physics may be
manifest. In the early years of the 21st century, if the technical challenges
can be met, the proposed BTeV experiment should have the best sensitivity for
rare effects both in charm and in beauty.


title: Searching for CP Violation in Pion Decay

abstract:
  Surprisingly, until recently CP violation in pion decay was not ruled out
experimentally even at the percent level. I have derived the first experimental
limit, $-0.01<A_{CP}<0.02$, from old data on the anomalous magnetic moment
$g-2$ of the muon. New data from the Brookhaven $g-2$ experiment might extend
the search by a few orders of magnitude, but probably will not probe the
theoretically-interesting sub-$10^{-7}$ regime.


title: Neutrinos: A Glimpse Beyond the Standard Model

abstract:
  After a review of the early history of neutrinos and their detection, we
analyze the different types of models that extend the standard model to massive
neutrinos. We emphasize the generic nature of maximal mixing between muon and
tau neutrinos, given simple assumptions based on grand unification.


title: Aspects of Soft and Spontaneous CP Violation

abstract:
  We study four different models for CP violation: the standard (KM) model, the
aspon model of spontaneous breaking and two models of soft breaking. In all
except the standard model, the strong CP problem is addressed and solved.
Testable predictions for the area of the unitarity triangle and for
(epsilon'/epsilon)_K are emphasized. The issue of CP violation may well become
the first place where the standard model of particle theory is shown
definitively to be deficient. There are two reasons for expecting this to
happen: (1) the strong CP problem is still not understood in the unadorned
standard model and (2) the KM mechanism, although unquestionably present, may
not provide the full explanation of epsilon_K and (epsilon'/epsilon)_K.


title:
Photon-Proton and Photon-Photon Scattering from Nucleon-Nucleon Forward
  Amplitudes

abstract:
  We show that the data on $\gamma p$ and $\gamma\gamma$ interactions can be
derived from the $pp$ and $\bar p p$ forward scattering amplitudes using vector
meson dominance and the additive quark model. The nucleon-nucleon data are
parameterized using a model where high energy cross sections rise with energy
as a consequence of the increasing numbers of soft partons populating the
colliding particles. We present detailed descriptions of the data on the total
and elastic cross sections, the ratio of the real to imaginary part of the
forward scattering amplitude, and on the slope of the differential cross
sections for $pp$, $\bar p p$, $\gamma p$, $\gamma\gamma$, $\gamma p \to \gamma
V$ and $\gamma\gamma \to V_i V_j$ reactions, where $V= \rho, \omega, \phi$. We
make a wide range of predictions for future HERA and LHC experiments and for
$\gamma\gamma$ measurements at LEP.


title: GUT Cosmic Magnetic Fields in a Warm Inflationary Universe

abstract:
  Sources of magnetic fields from grand unified theories are studied in the
warm inflation regime. A ferromagnetic Savvidy vacuum scenario is presented
that yields observationally interesting large scale magnetic fields. As an
intermediate step, a general analysis is made of defect production at the onset
of warm inflation and monopole constraints are obtained. Many features of this
Savvidy vacuum scenario are applicable within a supercooled inflation regime
and these points are discussed.


title: Bose-Einstein Condensation of Atoms and Thermal Field Theory

abstract:
  The Bose-Einstein condensation of atoms can be conveniently formulated as a
problem in thermal quantum field theory. There are many properties of the
equilibrium system and its collective excitations that can be studied
experimentally. The remarkable experimental control over all aspects of the
system make it an ideal testing ground for the methods of thermal field theory.


title:
Cosmological Phase Transitions and Radius Stabilization in Higher
  Dimensions

abstract:
  Recently there has been considerable interest in field theories and string
theories with large extra spacetime dimensions. In this paper, we explore the
role of such extra dimensions for cosmology, focusing on cosmological phase
transitions in field theory and the Hagedorn transition and radius
stabilization in string theory. In each case, we find that significant
distinctions emerge from the usual case in which such large extra dimensions
are absent. For example, for temperatures larger than the scale of the
compactification radii, we show that the critical temperature above which
symmetry restoration occurs is reduced relative to the usual four-dimensional
case, and consequently cosmological phase transitions in extra dimensions are
delayed. Furthermore, we argue that if phase transitions do occur at
temperatures larger than the compactification scale, then they cannot be of
first-order type. Extending our analysis to string theories with large internal
dimensions, we focus on the Hagedorn transition and the new features that arise
due to the presence of large internal dimensions. We also consider the role of
thermal effects in establishing a potential for the radius of the compactified
dimension, and we use this to propose a thermal mechanism for generating and
stabilizing a large radius of compactification.


title: Fuzzy Bag Models

abstract:
  We show how hadronic bag models can be generalized to implement effects of a
smooth and extended boundary. Our approach is based on fuzzy set theory and can
be straightforwardly applied to any type of bag model. We illustrate the
underlying ideas by calculating static nucleon properties in a fuzzy chiral bag
model.


title:
Monte Carlo Estimate of Finite Size Effects in Quark-Gluon Plasma
  Formation

abstract:
  Using lattice simulations of quenched QCD we estimate the finite size effects
present when a gluon plasma equilibrates in a slab geometry, i.e., finite width
but large transverse dimensions. Significant differences are observed in the
free energy density for the slab when compared with bulk behavior. A small
shift in the critical temperature is also seen. The free energy required to
liberate heavy quarks relative to bulk is measured using Polyakov loops; the
additional free energy required is on the order of 30-40 MeV at 2-3 T_c.


title: Is Warm Inflation Possible?

abstract:
  We show that it is extremely difficult and perhaps even impossible to have
inflation supported by thermal effects.


title: How degenerate can cosmological neutrinos be?

abstract:
  There are well-known bounds on light neutrino masses from cosmological energy
density arguments. These arguments assume the neutrinos to be non-degenerate.
We show how these bounds are affected if the neutrinos are degenerate. In this
case, we obtain correlated bounds between neutrino mass and degeneracy.


title:
Second order QCD corrections to the forward-backward asymmetry in e^+e^-
  - collisions

abstract:
  The sentence, 11th line below Eq. (30), starting with "Further in [14] one
has included all interference terms ...." is wrong and has been corrected.
Second line below Eq. (40) m_bar(m)=m is replaced by m_bar(\mu_0)=\mu_0 with
\mu_0=4.10 GeV, \mu_0=1.30 GeV and \mu_0=166.1 GeV for bottom, charm and top
respectively. The numbers in the second and third column of table 3 are a
little bit changed. In the acknowledgement the funding agency is mentioned and
one reference i.e. [20] is added.


title: On J/psi Production in Nuclear Collisions

abstract:
  Data on J/psi production in inelastic proton-proton, proton-nucleus and
nucleus-nucleus interactions at 158 A GeV are analyzed and it is shown that the
ratio of mean multiplicities of J/psi mesons and pions is the same for all
these collisions. This observation is difficult to understand within current
models of J/psi production in nuclear collisions based on the assumption of
hard QCD creation of charm quarks.


title: Double Spin Asymmetries in P-wave Charmonium Hadroproduction

abstract:
  We discuss the double spin asymmetries in P-wave charmonium hadroproduction
with non-zero transverse momenta at fixed target energies, $\sqrt{s}\simeq40$
GeV, within the framework of the NRQCD factorization approach. The size of the
asymmetries and the projected statistical errors in a future option of HERA
with longitudinally polarized protons scattering off a polarized target
(HERA-$\vec N$) are calculated. Measurements of the $\chi_{c1}$ and $\chi_{c2}$
decays into dilepton plus photon should allow to distinguish between different
parametrizations for the polarized gluon distribution in the proton. At higher
energies ($\sqrt{s}=200$ GeV) the situation appears less favourable with the
presently envisaged integrated luminosities of the polarized RHIC collider.


title: QCD thermodynamics from 3d adjoint Higgs model

abstract:
  The screening masses of hot SU(N) gauge theory, defined as poles of the
corresponding propagators are studied in 3d adjoint Higgs model, considered as
an effective theory of QCD, using coupled gap equations and lattice Monte-Carlo
simulations (for N=2). Using so-called lambda gauges non-perturbative evidence
for gauge independence of the pole masses within this class of gauges is given.
A possible application of the screening masses for the resummation of the free
energy is discussed.


title: Bimaximal Neutrino Mixing and Neutrino Mass Matrix

abstract:
  We show that the bimaximal neutrino mixing pattern suggested by the solar and
atmospheric neutrino data can be derived from the maximal, symmetric, four
neutrino mixing in the limit that one of the neutrinos is made heavy. Imposing
the constraints of no neutrinoless double beta decay and a 20% hot dark matter
component of the universe leads to a three neutrino mass matrix recently
suggested by Georgi and Glashow. Our result can be useful in constructing
theoretical models for the bimaximal pattern. We illustrate this by a simple
example.


title: Allowed parameter regions for a general inflation moded

abstract:
  The early Universe inflation is well known as a promising theory to explain
the origin of large scale structure of Universe and to solve the early universe
pressing problems. For a resonable inflation model, the potential during
inflation must be very flat in, at least, the direction of the inflaton. To
construct the inflaton potential all the known related astrophysics
observations should be included. For a general tree-level hybrid inflation
potential, which is not discussed fully so far, the parameters in it are shown
how to be constrained via the astrophysics data observed and to be obtained to
the expected accuracy, and consistent cosmology requirements.


title: Light quark masses and CKM matrix elements from lattice QCD

abstract:
  I give a brief overview of recent results from lattice QCD calculations which
are relevant for the phenomenology of the Standard Model. I discuss, in
particular, the lattice determination of light quark masses and the calculation
of those hadronic quantities, such as semileptonic form factors, decay
constants and B-parameters, which are of particular interest for the analysis
of the CKM mixing matrix and the origin of CP violation.


title: Five-leg photon-neutrino interactions

abstract:
  In a first part, we justify the feasibility of substituting a photon leg by a
neutrino current in the Euler-Heisenberg Lagrangian to obtain an effective
Lagrangian for the process $\gamma\nu\to\gamma\gamma \nu$ and its crossed
reactions.
  We establish the link between these processes and the four-photon scattering
in both the Standard Model and the effective theory. As an application, we
compute in this effective theory the processes $\gamma\nu\to\gamma\gamma\nu$
and $\gamma\gamma\to\gamma{\nu}\bar\nu$ and show how to use the
$\gamma\gamma\to\gamma\gamma$ results as a check. We settle the question of the
disagreement between two computations in the literature concerning the reaction
$\gamma\gamma\to \gamma \nu\bar\nu$. In the second part, we present results of
the direct computation of the photon-neutrino five-leg processes in the
Standard Model, discuss possible astrophysical implications of our results, and
provide simple fits to the exact expressions.


title:
Towards a Quantum Transport Description of Particles with finite Mass
  Width

abstract:
  The effects of the propagation of particles which have a finite life time and
an according width in their mass spectrum are discussed in the context of
transport descriptions. In the first part the coupling of soft photon modes to
a source of charged particles is studied in a classical model which can be
solved completely in analytical terms. The solution corresponds to a
re-summation of certain field theory diagrams. The second part addresses the
derivation of transport equations which also account for the damping width of
the particles. The $\Phi$-derivable method of Baym is used to derive a
self-consistent and conserving scheme. For this scheme a conserved
energy-momentum tensor can be constructed. Furthermore, a kinetic entropy can
be derived which besides the standard quasi-particle part also includes
contributions from fluctuation.


title:
Slow Magnetic Monopole: Interaction with Matter and New Possibility of
  Their Detection

abstract:
  The possibility of existence of a magnetic monopole has been surveyed by P.
Dirac even in 1931, and then from the point of view of the modern theory by
A.M. Polyakov and G.~ 'tHooft in 1974. Numerous and unsuccessful attempts of
experimental search for monopole in cosmic rays and on accelerators in high
energy particle collisions have been done. Also the searches have been carried
out in mica for monopole tracks as well as for relict monopoles, entrapped by
ferromagnetic inclusions in iron-ores, moon rock and meteorites. These
entrapped monopoles, when released, would have the lowest velocities
$\beta<10^{-6}$ and do not yield ionization at all, and are hard to detect.
Therefore it is necessary to examine thoroughly the mechanisms of slow heavy
monopole interaction with matter and their scale of energy loss.
  We discuss here the interaction of a massive slow magnetic monopole with
magnetically ordered matter, with conductors, superconductors and with
condensed matter in general. Our results indicate that the energy loss of a
slow supermassive monopole reach $10^{8} eV/cm$ and more if we take into
consideration the Cherenkov radiation of magnons or phonons and conductivity of
the media. A new method of search for cosmic and relict monopoles by
magnetically ordered film is considered too. This approach resembles the
traditional method of nuclear emulsion chamber. Apparently the proposed method
is particularly attractive for detection of relict monopoles, released from
melting iron ore.

categories: hep-ph astro-ph cond-mat.mtrl-sci hep-ex physics.ins-det


title: GUT and SUSY Breaking by the Same Field

abstract:
  We present a model in which the same modulus field breaks both SUSY and a
simple GUT gauge group down to the SM gauge group. The modulus is stabilized by
the inverted hierarchy mechanism in a perturbative region so that the model is
calculable. This is the first example of this kind in the literature. All mass
scales (other than the Planck scale) are generated dynamically. In one of the
models doublet-triplet splitting is achieved naturally by the sliding singlet
mechanism while another model requires fine tuning. The gauge mediation
contribution to the right handed slepton (mass)$^2$ is negative. But, for the
modulus vacuum expectation value close to the GUT scale, the supergravity
contribution to the slepton (mass)$^2$ is comparable to the gauge mediation
contribution and thus a realistic spectrum can be attained.


title: Supergravity Miracles: Phenomenology with Gravitational Divergences

abstract:
  The properties of singlet fields in supergravity background are discussed.
Particularly, it is shown that the ${\cal{O}}(\Lambda^{2})$ contributions to
their one-point function lead to novel derivations of effective scales such as
the $\mu$ parameter, a messenger scale, an intermediate symmetry-breaking
scale, and the unification scale, in terms of the scale of spontaneous
supersymmetry-breaking in a hidden sector.The singlet one-point function
effectively serves as a messenger of supersymmetry breaking.


title: B decay and the Upsilon mass

abstract:
  Theoretical predictions for inclusive semileptonic B decay rates are
rewritten in terms of the Upsilon(1S) meson mass instead of the b quark mass,
using a modified perturbation expansion. This method gives theoretically
consistent and phenomenologically useful results. Perturbation theory is well
behaved, and the largest theoretical error in the predictions coming from the
uncertainty in the quark mass is eliminated. The results are applied to the
determination of $|V_{cb}|$, $|V_{ub}|$, and $\lambda_1$.


title: Effect of Flavour Oscillations on the Detection of Supernova Neutrinos

abstract:
  Neutrinos and antineutrinos of all three flavours are emitted during the post
bounce phase of a core collapse supernova with $\numu/\nutau (\anumu/\anutau)$
having average energies more than that of $\nue(\anue)$. They can be detected
by the new earth bound detector like SNO and Super-Kamiokande which are
sensitive to neutrinos of all three flavours. In this letter we consider the
effect of flavour oscillations on the neutrino flux and their expected number
of events at the detector. We do a three-generation analysis and for the mass
and mixing schemes we first consider the threefold maximal mixing model
consistent with the solar and the atmospheric neutrino data and next a scenario
with one $\Delta m^2 \sim 10^{-11} eV^2$ (solar range) and the other $\Delta
m^2 \sim 10^{-18} eV^2$, for which the oscillation length is of the order of
the supernova distance. In both these scenarios there are no matter effects in
the resultant neutrino spectrum and one is concerned with vacuum oscillations.
We find that though neutrino oscillations result in a depletion in the number
of $\nue$ and $\anue$ coming from the supernova, the actual signals at the
detectors are appreciable enhanced.


title: Pionium lifetime corrections

abstract:
  Pionium lifetime corrections are evaluated in the frameworks of constrained
Bethe-Salpeter equation and chiral perturbation theory. Corrections of order
$O(\alpha)$ are calculated with respect to the conventional lowest-order
formula, in which the strong interaction amplitude has been calculated to
two-loop order with charged pion masses. The total correction is found to be of
the order of $(6.1\pm 2.0)%$.


title: Long Lived Superheavy Dark Matter with Discrete Gauge Symmetries

abstract:
  The recently observed ultra-high energy (UHE) cosmic rays beyond the
Greisen-Zatsepin-Kuzmin bound can be explained by the decays of some superheavy
$X$ particles forming a part of dark matter in our universe. We consider
various discrete gauge symmetries ${\bf Z}_N$ to ensure the required long
lifetime ($\tau_X \simeq 10^{10}-10^{22} years$) of the $X$ particle to explain
the UHE cosmic rays in the minimal supersymmetric standard model (MSSM) with
massive Majorana neutrinos. We show that there is no anomaly-free discrete
gauge symmetry to make the lifetime of the $X$ particle sufficiently long in
the MSSM with the $X$ particle. We find, however, possible solutions to this
problem especially by enlarging the particle contents in the MSSM. We show a
number of solutions introducing an extra pair of singlets $Y$ and $\bar{Y}$
which have fractional ${\bf Z}_N$ (N=2,3) charges. The present experimental
constraints on the $X$ particle are briefly discussed.


title: Fock Space Distributions, Structure Functions, Higher Twists and Small x

abstract:
  We compute quark structure functions and the intrinsic Fock space
distribution of sea quarks in a hadron wavefunction at small x. The computation
is performed in an effective theory at small x where the gluon field is treated
classically. At $Q^2$ large compared to an intrinsic scale associated with the
density of gluons $\mu^2$, large compared to the QCD scale $\Lambda^2_{QCD}$,
and large compared to the quark mass squared $M^2$, the Fock space distribution
of quarks is identical to the distribution function measured in deep inelastic
scattering. For $Q^2 \le M^2$ but $Q^2 >> \mu^2$, the quark distribution is
computed in terms of the gluon distribution function and explicit expressions
are obtained. For $Q^2 \le \mu^2$ but $Q^2 >> \Lambda_{QCD}^2$ we obtain formal
expressions for the quark distribution functions in terms of the glue. An
evaluation of these requires a renormalization group analysis of the gluon
distribution function in the regime of high parton density. For light quarks at
high $Q^2$, the DGLAP flavor singlet evolution equations for the parton
distributions are recovered. Explicit expressions are given for heavy quark
structure functions at small x.