Energy Loss and Flow of Heavy Quarks in Au + Au Collisions at √sNN = 200 GeV

PHENIX Collaboration

Enokizono Akitomo

Hachiya Takashi

Harada Hiroyuki

Haruna Kohta

Homma Kensuke

Nakamiya Yoshihide

Nakamura Tomoaki

Ouchida Misaki

Sakata Hirokazu

Shigaki Kenta

Sugitate Toru

Tsuchimoto Yuji

Physical Review Letters

The PHENIX experiment at the BNL Relativistic Heavy Ion Collider (RHIC) has measured electrons with 0.3 < pT < 9 GeV/c at midrapidity (|y|<0.35) from heavy-flavor (charm and bottom) decays in Au + Au collisions at √sNN = 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 energies. A large azimuthal anisotropy v2 with respect to the reaction plane is observed for 0.5 < pT < 5 GeV/c indicating substantial heavy-flavor elliptic flow. Both RAA and v2 show a pT dependence different from those of neutral pions. A comparison to transport models which simultaneously describe RAA(pT) and v2(pT) suggests that the viscosity to entropy density ratio is close to the conjectured quantum lower bound, i.e., near a perfect fluid.

eng

American Physical Society

Copyright (c) 2007 The American Physical Society.

[ISSN] 0031-9007

[DOI] 10.1103/PhysRevLett.98.172301

[NCID] AA00773679

[DOI] http://dx.doi.org/10.1103/PhysRevLett.98.172301