Modification of hadron transverse momentum spectra in heavy ion collisions

par Dr Simone Schuchmann (IKF Francfort)

vendredi 11 déc. 2015, 10:45 → 12:00 Europe/Paris

Salle Mondrian (IPHC, Bât. 25)

Relativistic heavy-ion collisions produce a hot and dense state of strongly interacting matter, the Quark-Gluon Plasma (QGP). This state was presumably also formed a few microseconds after the big-bang. The presence of QGP has been observed to affect the yields of final state hadrons. Quarks and gluons from initial hard scatterings with high-transverse momentum (p_T) may lose energy while traversing the medium, resulting in the suppression of hadrons at high p_T with respect to the reference values obtained from binary-collision scaled measurements in pp collisions. This modification is quantified as the nuclear modification factor R_AA.

At high p_T, the corresponding analysis of hadrons with different quark content may reveal peculiarities regarding the partonic in-medium energy loss, such as the composition of energy loss sources as well as the strength of the medium influence.

At low p_T, this analysis sheds light on the hadron production mechanisms as well as on the influence of initial state effects, such as collective flow. All these effects are linked to the medium properties, e.g. the transport coefficient and the viscosity, which are essential for the characterization of the strongly interacting system created in heavy-ion collisions.

The focus of the presentation will be on recent R_AA measurements and on the interpretation of their shape in different momentum regions.