Minijet deformation and charge-independent angular correlations on momentum subspace (eta, phi) in Au-Au collisions at root S-NN=130 GeV
Minijet deformation and charge-independent angular correlations on momentum subspace (eta, phi) in Au-Au collisions at root S-NN=130 GeV
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DOI：
10.1103/physrevc.73.064907
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发表时间：
2004-11
影响因子：
3.1
通讯作者：
Star Collaboration;J. Adams;E. al.
中科院分区：
文献类型：
--
作者：
Star Collaboration;J. Adams;E. al.
本文测量了横动量为0.15 ≤ p_t ≤ 2 GeV/c的所有原初带电强子的角差变量η 1-η 2（赝快度）和φ 1-φ 2（方位角）的两粒子关联。|η| ≤ 1.3。在相对角度的宽范围内观察到大幅度相关性，其中不同的结构出现在同侧和远侧（即，相对方位角小于π/2或大于π/2）。主要的相关结构包括与椭圆流加上一个强大的，同侧峰。据推测，后者的结果从关联强子与半硬部分子散射在早期阶段的重离子碰撞，产生一个喷流样的相关峰在小的相对角度。从外围碰撞到中心碰撞，η 1 − η 2上的喷流状峰的宽度增加了2.3倍，表明半硬散射部分子与膨胀介质的强耦合。这里介绍的射流分析的新方法提供了低横向动量远低于微扰量子色动力学和标准碎裂模型适用的运动学范围的散射部分子。
Measurements of two-particle correlations on angular difference variables η1 − η2 (pseudorapidity) and φ1 − φ2 (azimuth) are presented for all primary charged hadrons with transverse momentum 0.15 ≤ p_t ≤ 2 GeV/c and |η| ≤ 1.3 from Au-Au collisions at √s_(NN) = 130 GeV. Large-amplitude correlations are observed over a broad range in relative angles where distinct structures appear on the same-side and away-side (i.e., relative azimuth less than π/2 or greater than π/2). The principal correlation structures include that associated with elliptic flow plus a strong, same-side peak. It is hypothesized that the latter results from correlated hadrons associated with semi-hard parton scattering in the early stage of the heavy-ion collision which produces a jet-like correlation peak at small relative angles. The width of the jet-like peak on η1 − η2 increases by a factor 2.3 from peripheral to central collisions, suggesting strong coupling of semi-hard scattered partons to a longitudinally-expanding medium. The new methods of jet analysis introduced here provide access to scattered partons at low transverse momentum well below the kinematic range where perturbative quantum chromodynamics and standard fragmentation models are applicable.