HIC for FAIR logo Nuclear Physics Colloquium

Location:  FIAS, Ruth-Moufang-Str. 1, Seminar Room 100
Time: Wednesday, January 29, 2014, 10:00-11:00am
(plus 10min for discussion)
Contact: hees@fias.uni-frankfurt.de

Effects of initial state fluctuations and jets on flow observables in heavy ion collisions

Rafael Derradi de Souza (University of Rio de Janeiro)

The hot and dense system resulting from heavy ion collisions has long been thought to exhibit collective behavior. One of the main observables related to this collectivity is the transverse momentum anisotropy of the produced particles. Recent studies have demonstrated that the system formed in such collisions may present initial state inhomogeneities that could have adverse effects on the flow coefficients and thus merit further investigation. Also, the presence of jets of particles arising from hard scatterings in the initial stages of the collision may introduce independent sources of particle correlations on the final observables.

In this work, we studied the behavior of the elliptic flow coefficient obtained from events generated using the hydrodynamic-based code NeXSPheRIO. This model allows the use of smooth or fluctuating initial condition for the system evolution and produces a set of final particles that can be analysed with common experimental techniques. In addition, we have also superimposed events simulated with NeXSPheRIO and proton-proton collisions simulated with PYTHIA such that the resulting event is composed by a hydrodynamics-like part and another jet-like part. Even in this simplified model which does not include any interactions of particles from PYTHIA and from hydrodynamics, our results show agreement with measured elliptic flow from the STAR experiment up to a $p_t$ of 6 GeV/c in Au+Au collisions at 200 GeV. In this context, the understanding of such effects on the final observables may be paramount for interpreting the experimental data.

 Nuclear Physics Colloquium Homepage