Trobada de Nadal 2002




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:

Gràcies a tots per la vostra col.laboració. Romanem a la vostra disposició.

Joan Solà (

Joan Soto (


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)




Dijous 19 de Desembre:

(9.30-10.30) ............ Frederic Teubert (CERN)

(10.30-11.15) .......... Rafel Escribano (UAB)

******   Coffee Break    ******

(11.45-12.30 ).......... David Mateos (PI)

(12.30-13.30) .......... Paul Townsend (Cambridge)

(13.30-15.00) *******     Lunch      *********

(15.00-16.00)...........C.W. Bauer (Sant Diego)

(16.00-16.45)...........Ramon Toldra (Oxford)

(16.45-17.15) ******    Coffee Break    *****

(17.15-18.00)............Francesc Ferrer (Oxford)

(18.00-18.45)............Oscar Blanch (IFAE)

(18.45-19.45)............Toni Grifols (UAB)

Divendres 20 de Desembre:

(9.30-10.15)...........Joan Simon (Weizman)

(10.15-11.00)..........José María Roman (CSIC)

(11.00-11.30) *****    Coffee Break    ******

(11.30-12.15)..........Tomeu Fiol (Weizman)

(12.15-13.15)..........Jorge Russo (UB)

(13.15-14.30) *******     Lunch      ********

(14.30-15.15)...........Albert Roura (Maryland)

(15.15-16.00)..........Gabriel Martínez (IEEC)

(16.00-16.30) ******   Coffee Break    ******

(16.30-17.15)..........Siannah Peñaranda (MPI)

(17.15-18:00)..........Jaume Guasch (PSI)

(18.00-19.00)..........Wolfgang Hollik (MPI)

(21:00 -??)     ****  Dinner in Barcelona     ***


Xerrades (Seniors)


  • Toni Grifols (UAB)

    TITLE: Neutrino mass: status and prospects


    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


    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


    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 R-charge operators, previously obtained from the study of the plane-wave limit of anti de Sitter space. A number of new soliton string solutions will be presented. We will also describe some non-trivial
    semiclassical processes involving string solitons and their holographic duals.

  • Paul Townsend (Cambridge U.)

    TITLE: SUSY in motion


    A review will be given of time-dependent supersymmetry preserving configurations in
    supersymmetric field theories, and string/M-theory.


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 non-perturbative 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)

    : The MAGIC Telescope, at last, in "El Roque de los muchachos"

    : 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


    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 Ultra-High-Energy Cosmic Rays: clues to their origin


    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


    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.


    In SUSY Models the couplings of Higgs particles to fermions receive large corrections which are non-decoupling 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


    Effects in conformal field theories are holographically dual to branes in AdS spaces.
    We will describe how supersymmetry-preserving non-planar 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


    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 weak-interaction 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 self-couplings


    To establish the Higgs mechanism experimentally in an unambiguous way, the characteristic Higgs self-interaction potential must be reconstructed. This task requires the measurement of the trilinear and quartic self-couplings as predicted in the SM or in SUSY theories. We investigate how far the MSSM Higgs potential reproduces the SM potential when the non-standard particles are heavy by exploring the decoupling behaviour of the radiative corrections of heavy Higgs particles and heavy top-squarks to the h0 self-couplings at the one-loop 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 self-similar 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: Einstein-Langevin as the large N limit for quantum metric fluctuations


    The so-called Einstein-Langevin 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 Einstein-Langevin 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


    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 non-singular relative, the "null-brane" orbifold. The study of D-branes in these scenarios, in an AdS/CFT context, suggests the way to define string theory in time dependent backgrounds non-perturbatively. 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


    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$10~GeV), the W-boson mass (\MW=80.368$\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


    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.