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Energy Loss and Flow of Heavy Quarks in Au+Au Collisions at $\sqrt{s_{NN}}$ = 200 GeV (2007)

Abstract

The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) has measured electrons from heavy flavor (charm and bottom) decays for 0.3 < p_T < 9 GeV/c at midrapidity (|y| < 0.35) in Au+Au collisions at sqrt(s_NN) = 200 GeV. The nuclear modification factor RAA relative to p+p collisions shows a strong suppression in central Au+Au collisions, indicating substantial energy loss of heavy quarks in the medium produced at RHIC. A large azimuthal anisotropy, v_2, with respect to the reaction plane is observed for 0.5 < p_T < 5 GeV/c indicating non-zero heavy flavor elliptic flow. A simultaneous description of RAA(p_T) and v2(p_T) constrains the existing models of heavy-quark rescattering in strongly interacting matter and provides information on the transport properties of the produced medium. In particular, a viscosity to entropy density ratio close to the conjectured quantum lower bound, i.e. near a perfect fluid, is suggested.

Publication details

Download	http://hal.in2p3.fr/in2p3-00118439/en/
Publisher	HAL - CCSd - CNRS
Contributors	Suzanne Robert
Repository	CCSd/HAL : e-articles server (based on gBUS) (France)
Keywords	Physics/Nuclear Experiment
Type	ART_ACL