Measurements of mass-dependent azimuthal anisotropy in central
+ Au,
+ Au, and
He + Au collisions at
= 200 GeV
=200GeVでの
+ Au,
+ Au, and
He + Au中心衝突における質量依存方位角異方性の測定
Adare, A.*; 長谷川 勝一
; 今井 憲一; 佐甲 博之
; 佐藤 進
; 谷田 聖
; PHENIX Collaboration*; 他347名*
Adare, A.*; Hasegawa, Shoichi; Imai, Kenichi; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 347 of others*
We present measurements of the transverse-momentum dependence of elliptic flow
for identified pions and (anti)protons at midrapidity (
), in 0% - 5% central
+ Au and
He + Au collisions at
= 200 GeV. When taken together with previously published measurements in
+ Au collisions at
= 200 GeV, the results cover a broad range of small-collision-system multiplicities and intrinsic initial geometries. We observe a clear mass-dependent splitting of
in
+ Au and
He + Au collisions, just as in large nucleus-nucleus (
+
) collisions, and a smaller splitting in
+ Au collisions. Both hydrodynamic and transport model calculations successfully describe the data at low
(
GeV/
), but fail to describe various features at higher
. In all systems, the
values follow an approximate quark-number scaling as a function of the hadron transverse kinetic energy per constituent quark(
), which was also seen previously in
+
collisions.