Size fluctuations of the initial source and the event-by-event transverse momentum fluctuations in relativistic heavy-ion collisions

摘要

We show that the event-by-event fluctuations of the transverse size of theinitial source, which follow directly from the Glauber treatment of theearliest stage of relativistic heavy-ion collisions, cause, after hydrodynamicevolution, fluctuations of the transverse flow velocity at hadronic freeze-out.This in turn leads to event-by-event fluctuations of the average transversemomentum, p_T. Simulations with GLISSANDO for the Glauber phase, followed by arealistic hydrodynamic evolution and statistical hadronization carried out withTHERMINATOR, lead to agreement with the RHIC data. In particular, the magnitudeof the effect, its centrality dependence, and the weak dependence on theincident energy are properly reproduced. Our results show that bulk of theobserved event-by-event p_T fluctuations may be explained by the fluctuationsof the size of the initial source.