**Location:** Cyclotron Building (434), Seminar
Room

**Friday, February 5, 4:00pm**

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**

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**

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**

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.

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