2015/05/31 by STAR Collaboration, L. Adamczyk, J. K. Adkins +325 · 1 citation
Physics and Astronomy · #nucl-ex #nucl-th
paper · pdf · doi:10.1103/physrevlett.115.222301
published as Phys. Rev. Lett. 115, 222301 (2015) · Final paper version accepted for publication in Phys. Rev. Lett. New version includes comparisons to a constituent quark glauber model
arxiv created 2015/11/07 · arxiv updated 2015/12/02
Collisions between prolate uranium nuclei are used to study how particle production and azimuthal anisotropies depend on initial geometry in heavy-ion collisions. We report the two- and four-particle cumulants, v2\2\ and v2\4\, for charged hadrons from U+U collisions at √s\rm NN = 193 GeV and Au+Au collisions at √s\rm NN = 200 GeV. Nearly fully overlapping collisions are selected based on the amount of energy deposited by spectators in the STAR Zero Degree Calorimeters (ZDCs). Within this sample, the observed dependence of v2\2\ on multiplicity demonstrates that ZDC information combined with multiplicity can preferentially select different overlap configurations in U+U collisions. An initial-state model with gluon saturation describes the slope of v2\2\ as a function of multiplicity in central collisions better than one based on Glauber with a two-component multiplicity model.