Nuclear Theory Seminars at Texas A&M: Spring 2010

Location: Cyclotron Building (434), Seminar Room

Friday, February 5, 4:00pm

    Nuclear Seminar
    Ricardo Rodriguez -Cyclotron Institute Texas A&M-

    " EFFECTS OF FLUCTUATIONS IN THE FIREBALL ON JET QUENCHING OBSERVABLES AT RHIC "

    Abstract

In high energy nuclear collisions, jet energy loss is usually modeled with smooth, homogeneous backgrounds.
We study the effect of realistic, inhomogeneous backgrounds by implementing Glauber profiles with fluctuations.

            We observe how the extraction of the energy loss parameter is affected by these fluctuations and we calculate their effect on
        observables like single hadron spectra, nuclear modification factor, azimuthal asymmetry, back-to-back correlations
        and triggered fragmentation functions

Friday, February 19, 4:00pm

    Nuclear Seminar
   Michel Gonin – Ecole Polytechnique – France

    "The Tokai to Kamioka Long Baseline Neutrino Oscillation Experiment"

    Abstract

        Physicists from the Japanese-led multi-national T2K neutrino collaboration announced last November that they detected the first
   neutrino events generated by their newly built neutrino beam at the J-PARC accelerator laboratory in Tokai, Japan. This detection
therefore marks the beginning of the operational phase of the new “off-axis” T2K experiment, a 474 physicist, 13 nation collaboration to
measure new properties of the ghostly neutrino.

        Measurements over the last few decades, notably by the Super Kamiokande experiments in western Japan or the SNO collaboration in
  Canada, have shown that neutrinos possess a strange property. Neutrino oscillations, which require neutrinos to have mass and
    therefore were not allowed in our previous theoretical understanding of particle physics, probe new physical laws and are thus of great
    interest in the study of the fundamental constituents of matter. They could be in particular related to the mystery of why there is more
    matter than anti-matter in the universe, and thus are the focus of intense study worldwide.

Friday, February 26, 4:00pm

    Nuclear Seminar
    Taesoo Song -Cyclotron Institute Texas A&M-

    " RAA OF J/Psi NEAR MID-RAPIDY IN HEAVY ION COLLISIONS AT sqrt(S) = 200 GeV "

    Abstract

        We build up a model to reproduce the experimentally measured R_{AA} of J/psi near midrapidty in Au+Au
    collision at sqrt{s_{NN}}=200 GeV. The model takes into account the J/psi suppression from the quark-gluon
    plasma and hadron gas as well as the nuclear absorption of primordial charmonia and the regeneration effects
    at the hadronization stage, and hence is a generalization of the two component model. The improvements in this
    work are twofold: the addition of the initial local temperature profile and a consistent use of QCD NLO formula
    for both the dissociation cross section in the hadron gas and the thermal decay widths in the quark-gluon plasma
    for the charmonium states.

        The initial local temperature profile is determined from the assumption that the local entropy density is proportional to
    a formula involving the number densities of the number of participants and of the binary collisions that reproduces
    the multiplicities of charged particles at chemical freeze-out. The initial local temperature profile brings about a kink
    in the R_{AA} curve due to the initial melting of J/psi.

        The initially formed fireball, composed of weakly interacting quarks and gluons with thermal masses that are extracted
    from lattice QCD, follows an isentropic expansion with cylindrical symmetry. The fit reproduces well the Au+Au as well
    as the Cu+Cu data. The same method is applied to predict the R_{AA} expected from the Pb+Pb collision at LHC energy.

Friday, April 30, 4:00pm

Nuclear Seminar
Felix Reik -Cyclotron Institute Texas A&M-

"QUARKONIA AND HEAVY-QUARK RELAXATION TIMES IN THE QUARK-GLUON PLASMA"

Abstract

            I will present results from a thermodynamic T-matrix approach to calculate spectral functions of open and hidden
    heavy-quark systems in the Quark-Gluon Plasma. This enables the evaluation of quarkonium bound-state properties and heavy-quark
    diffusion on a common basis and thus to extract mutual constraints.

              An effective field-theoretical model combining color-Coulomb and confining terms is implemented with relativistic corrections and
    for different color channels. The model parameters are adjusted to reproduce the color-average heavy-quark free energy computed in
    thermal lattice QCD.

            Theoretical uncertainties in the static reduction scheme of the 4-dimensional Bethe-Salpeter equation are elucidated. The
    quarkonium spectral functions are used to calculate Euclidean correlators which are discussed in light of lattice QCD results, while
    heavy-quark relaxation rates and diffusion coefficients are extracted utilizing a Fokker-Planck treatment.

Friday, May 7, 4:00pm

    Nuclear Seminar
  Julian Hofmann -GSI- Helmholtz Center for Heavy Ion Research and Frankfurt Institute for Advanced Studies-


" DYNAMICAL GENERATION OF HADRONIC RESONANCES: AN OVERVIEW "

Abstract

            An understanding of the nature of hadronic resonances is one of theoutstanding issues of QCD. In this seminar I will give a short
    introduction to the generation of hadronic resonances using coupled-channel dynamics, followed by an overview over results obtained
    so far. The emphasis will be put on charmed meson an baryon resonances.

Previous seminars

Fall 2009
Spring 2009
Fall 2008
Spring 2008
Fall 2007
Spring 2007
Fall 2006
Spring 2006
Fall 2005
Spring 2005
Fall 2004
Spring 2004
Fall 2003

Nuclear theory group home page

Last updated: February 02/10
Maintained by Ricardo Rodriguez