Trobada de Nadal 2002
Presentació
Us informem que aquest any farem la segona edició de la Trobada
de Nadal, la qual tindrà lloc a Departament
d'E.C.M. de la UB entre els dies 19 i 20 de desembre
(els dos darrers dies lectius abans de les vacances de Nadal). Les xerrades
es faran a l'aula habitual de seminaris: Aula 505 del Dep. de FF.
La idea és, com l'any passat, poder conèixer i seguir el
treball que estan desenvolupant els fsics teòrics, d'altes energies
(i afins) de les nostres universitats i centres d'investigació
catalans (UB, UAB, UPC, IEEC...) que es troben en situació de postdoctorat
a l'estranger o que fa relativament poc que s'han incorporat. A tal fi,
aprofitant la tornada dels mateixos durant les festes nadalenques, organitzem
una sèrie de seminaris on exposaran temes relacionats amb els seus
darrers treballs. També comptem amb la participació d'algun
investigador senior que hem convidat especialment
per aquesta ocasió.
El programa detallat i actualitzat el podeu consultar a la pàgina
web del Dep. E.C.M., més concretament a: http://www.ecm.ub.es/hep/nadal.html
Gràcies a tots per la vostra col.laboració. Romanem a la
vostra disposició.
Joan Solà (sola@ifae.es)
Joan Soto (soto@ecm.ub.es)
Speakers Seniors Convidats
 Prof. Toni Grifols (UAB)
 Prof.Wolfgang Hollik (MPI Munich)
 Prof. Jorge Russo (UB/ICREA)
 Prof. Paul Townsend (Cambridge)
Speakers Juniors (confirmats)
 Oscar Blanch (IFAE)
 Rafel Escribano (UAB)
 Francesc Ferrer (Oxford U.)
 Tomeu Fiol (Weizmann I., Israel)
 Jaume Guasch (PSI, Suissa)
 Gabriel Martínez (IEEC, Barcelona)
 David Mateos (Perimeter Institute, Canada)
 Siannah Peñaranda (MPI Múnic, )
 J.M. Roman (CSIC, Madrid)
 Albert Roura (Maryland, US)
 Joan Simon (Weizman I., Israel)
 Frederic Teubert (CERN, Suissa)
 Ramon Toldra (Oxford U.)
Speaker del Seminari Extern (dijous 19 de novembre)
 C.W. Bauer (U.C., San Diego)
Programa/Shedule
Xerrades (Seniors)
 Toni Grifols (UAB)
TITLE: Neutrino mass: status and prospects
ABSTRACT:
We review the issue of absolute neutrino mass from the standpoint
of both laboratory experiments and astrophysics/cosmology.
 Wolfgang Hollik (MPI, Munich)
TITLE: Electroweak precision analyses and status of SM
and MSSM
ABSTRACT:
We review the status of the Standard Model and the Minimal Supersymmetric
Standard Model in the light of the precision experiments.
 Jorge Russo (UB/ICREA)
TITLE: Semiclassical physics of strings in AdS and large
N gauge theories
ABSTRACT:
By the AdS/CFT correspondence, semiclassical soliton solutions representing
highly excited string states can be identified with gauge theory operators.
In this way one can predict the anomalous dimension of certain operators
in the strong coupling limit. In particular, one provides a simple
alternative derivation of the formula for the dimension of large Rcharge
operators, previously obtained from the study of the planewave limit
of anti de Sitter space. A number of new soliton string solutions
will be presented. We will also describe some nontrivial
semiclassical processes involving string solitons and their holographic
duals.
 Paul Townsend (Cambridge U.)
TITLE: SUSY in motion
ABSTRACT:
A review will be given of timedependent supersymmetry preserving
configurations in
supersymmetric field theories, and string/Mtheory.
Xerrades (Juniors)
 Christian Bauer (UCSD)
TITLE: Factorization in QCD
ABSTRACT: One of the most important problems in particle phenomenology
is to disentangle short distance weak scale physics we are after from
long distance hadronization effects. This separation is achieved by
factorization theorems, in which the nonperturbative effects are
parameterized by a few universal objects which can be measured experimentally.
I will discuss a novel effective theory which allows to simply derive
factorization theorems for many different processes. Examples I will
discuss are exclusive and inclusive B decays, as well
as event shape distributions in e+ e collisions.
 Oscar Blanch (IFAE)
TITLE: The MAGIC Telescope, at last, in "El Roque de
los muchachos"
ABSTRACT: The MAGIC telescope is being installed in "El
Roque de los Muchachos"
(La Palma) to detect gamma rays from 10 GeV to 10 TeV. The MAGIC t is
telescope unique among Cherenkov Telescope since it adapted several
new
technologic developments. They are being integrated in the site and
MAGIC
will start to get physic data the first half of 2003.
 Rafel Escribano (UAB)
TITLE: Scalar meson exchange in V>P0P0gamma decays
ABSTRACT:
The complementarity between Chiral Perturbation Theory and the Linear
Sigma Model is exploited to study scalar meson exchange in V>P0P0gamma
decays. The recently reported experimental data on phi>pi0pi0gamma,
phi>pi0etagamma and rho>pi0pi0gamma can be satisfactorily
accommodated in our framework.
 Francesc Ferrer (Oxford U.)
TITLE: The sky distribution of UltraHighEnergy Cosmic
Rays: clues to their origin
ABSTRACT:
The highest energy cosmic rays observed must have a local origin
since they cannot propagate far through the CMB. An interesting
possibility is that they result from the slow decays of very massive
dark matter particles created at the end of inflation. If so there
should be anisotropies in the cosmic ray sky reflecting the distribution
of dark matter in the Galactic halo. The prospects for detecting this
with the Pierre Auger experiment, being constructed in Argentina,
will be discussed.
 Tomeu Fiol (Weizman I., Israel)
TITLE: The holographic principle and de Sitter space
ABSTRACT:
In the first part of this talk, I review the holographic principle
and its possible relevance in the quest for a theory of quantum gravity.
In the second part of the talk, I describe some puzzles that arise
when one considers quantum gravity in de Sitter space, and I present
some steps towards a holographic description of quantum gravity in
de Sitter space.
 Jaume Guasch (PSI, Switzerland)
TITLE: SUSY Higgs boson phenomenology at large \tan\beta:
new results.
ABSTRACT:
In SUSY Models the couplings of Higgs particles to fermions receive
large corrections which are nondecoupling and \tan\beta enhanced.
We review the
origin of these effects and present new results on the subject.
 David Mateos (Perimeter Institute, Canada)
TITLE: Defect Holography and the Masses of Hadrons
ABSTRACT:
Effects in conformal field theories are holographically dual to branes
in AdS spaces.
We will describe how supersymmetrypreserving nonplanar defects can
be introduced. We will also show how the masses of hadrons in a gauge
theory with matter in the fundamental
can be computed from spinning open strings attached to the brane.

Gabriel Martínez (IEEC/ICREA)
TITLE: The Weak Interaction in Core Collapse Supernova
ABSTRACT:
The understanding of core collapse supernova remains one of the current
challenges in astrophysical modeling. The weak interaction plays a
very important role in determining how the initial implosion of the
core results in the final explosion of the star. In this talk I will
present recent advances in the calculation of the relevant weakinteraction
processes. Their influence in the collapse, explosion and associated
nucleosynthesis will be discussed.

Siannah Peñaranda(MPI,Munich)
TITLE: The reconstruction of trilinear and quartic Higgs
boson selfcouplings
ABSTRACT:
To establish the Higgs mechanism experimentally in an unambiguous
way, the characteristic Higgs selfinteraction potential must be reconstructed.
This task requires the measurement of the trilinear and quartic selfcouplings
as predicted in the SM or in SUSY theories. We investigate how far
the MSSM Higgs potential reproduces the SM potential when the nonstandard
particles are heavy by exploring the decoupling behaviour of the radiative
corrections of heavy Higgs particles and heavy topsquarks to the
h0 selfcouplings at the oneloop level.
 José Maria Roman (CSIC, Madrid)
TITLE: Russian Doll Renormalization Group and Superconductivity
ABSTRACT: We show that an extension of the standard BCS Hamiltonian
leads to an infinite number of condensates with different energy gaps
and selfsimilar properties, described by a cyclic RG flow of the
BCS coupling constant which returns to its original value after a
finite RG time.

Albert Roura (Maryland, US)
TITLE: EinsteinLangevin as the large N limit for quantum
metric fluctuations
ABSTRACT:
The socalled EinsteinLangevin equation has been proposed in order
to extend the applications of the semiclassical theory of gravity
to those situations in which the fluctuations of the stress tensor
operator for the quantum matter fields are important. After briefly
reviewing some aspects of nonequilibrium quantum field thoery, it
will be explained how a stochastic description can be introduced to
gain information on quantum properties of simple open systems. This
will then be extended to the gravitational case by considering N quantum
matter fields interacting with the metric perturbations around a given
background spacetime. In particular, it will be shown that the correlation
functions obtained using the EinsteinLangevin equation are equivalent
to the leading order contribution in the large N limit to the correlation
functions that would follow from a purely quantum treatment.
 Joan Simon (Weizman I., Israel)
TITLE: Time dependence through lorentzian orbifolds
ABSTRACT:
The possibility of studying time dependent string scenarios through
lorentzian orbifold techniques is considered. Supersymmetry and absence
of closed causal curves select the parabolic orbifold and its nonsingular
relative, the "nullbrane" orbifold. The study of Dbranes
in these scenarios, in an AdS/CFT context, suggests the way to define
string theory in time dependent backgrounds nonperturbatively. Some
comments on other potentially interesting time dependent scenarios
in string theory will be briefly mentioned.
 Frederic Teubert (CERN, Switzerland)
TITLE: Precision tests of the electroweak interactions
at LEP/SLC
ABSTRACT:
The measurements performed at LEP and SLC have substantially improved
the precision of the tests of the Minimal Standard Model. The precision
is such that there is sensitivity to pure weak radiative corrections.
This allows to indirectly determine the top mass (\mt=178$\pm$10~GeV),
the Wboson mass (\MW=80.368$\pm$0.022~GeV), and to set an upper limit
on the Higgs boson mass of 193~GeV at 95\% confidence level.
 Ramon Toldra (Oxford Univ.)
TITLE: Ultra High Energy Cosmic Rays
ABSTRACT:
Several cosmic rays with energy exceeding 10^11 GeV have been detected
by different cosmic ray observatories. Understanding how microscopic
particles can be accelerated up to this macroscopic energy poses and
unsolved problem in astrophysics. Physics beyond the standard model
of the elementary particles provides testable explanations for such
ultra high energy events.
