Journal Article Measurement of D0 Azimuthal Anisotropy at Midrapidity in Au+Au Collisions at √sNN=200  GeV

STAR Collaboration  ,  Esumi, S.

118 ( 21 )  , p.212301 , 2017-05 , American Physical Society
We report the first measurement of the elliptic anisotropy (v2) of the charm meson D0 at midrapidity (|y|<1) in Au+Au collisions at √sNN=200  GeV. The measurement was conducted by the STAR experiment at RHIC utilizing a new high-resolution silicon tracker. The measured D0 v2 in 0%–80% centrality Au+Au collisions can be described by a viscous hydrodynamic calculation for a transverse momentum (pT) of less than 4  GeV/c. The D0 v2 as a function of transverse kinetic energy (mT−m0, where mT=√p2T+m20) is consistent with that of light mesons in 10%–40% centrality Au+Au collisions. These results suggest that charm quarks have achieved local thermal equilibrium with the medium created in such collisions. Several theoretical models, with the temperature-dependent, dimensionless charm spatial diffusion coefficient (2πTDs) in the range of ∼2–12, are able to simultaneously reproduce our D0 v2 result and our previously published results for the D0 nuclear modification factor.

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