"cfsall_20-60 5-7" of "Suppression of away-side jet fragments with respect to the reaction plane in Au+Au collisions at sqrt(s_NN) = 200 GeV"

BNL-RHIC. Pair correlations between large transverse momentum neutral pion triggers (pT= 4–7 GeV/c) andcharged hadron partners (pT= 3–7 GeV/c) in central (0–20%) and midcentral (20–60%) Au+Aucollisions are presented as a function of trigger orientation with respect to the reaction plane. Theparticles are at larger momentum than where jet shape modifications have been observed, and thecorrelations are sensitive to the energy loss of partons traveling through hot dense matter. An out-of-plane trigger particle produces only 26±20% of the away-side pairs that are observed opposite ofan in-plane trigger particle. In contrast, near-side jet fragments are consistent with no suppressionor dependence on trigger orientation with respect to the reaction plane. These observations arequalitatively consistent with a picture of little near-side parton energy loss either due to surface biasor fluctuations and increased away-side parton energy loss due to a long path through the medium.The away-side suppression as a function of reaction-plane angle is shown to be sensitive to both theenergy loss mechanism in and the space-time evolution of heavy-ion collisions. - {location: "https://www.phenix.bnl.gov/phenix/WWW/info/data/ppg116_data.html", description: "web page with data point"}

BNL-RHIC（布鲁克海文国家实验室相对论重离子对撞机）数据集展示了中心度0-20%与20-60%的金核-金核（Au+Au）碰撞中，大横动量中性π介子（neutral pion）触发粒子（横向动量$p_T=4–7 mathrm{GeV/c}$）与带电强子（charged hadron）伴生粒子（横向动量$p_T=3–7 mathrm{GeV/c}$）之间的成对关联，关联结果随触发粒子相对于反应平面（reaction plane）的方位角变化而变化。这些粒子的动量高于已观测到喷注形状修改的动量区间，且该成对关联对穿过热密物质的部分子（parton）的能量损失过程具有敏感性。面外触发粒子的对侧（away-side）成对信号产额仅为面内触发粒子所观测到的对侧成对信号的$26\%pm20\%$。与之相反，近侧（near-side）喷注碎片的产额未表现出抑制（suppression）效应，也与触发粒子相对于反应平面的方位角无关。上述观测结果与以下物理图像定性相符：由于表面偏置（surface bias）或涨落效应，近侧部分子的能量损失可忽略不计；而对侧部分子因穿过热密介质的路径更长，其能量损失显著增强。研究表明，对侧信号抑制程度随反应平面方位角的变化关系，既敏感于重离子碰撞中的部分子能量损失机制，也敏感于碰撞的时空演化（space-time evolution）过程。
- 数据来源：<https://www.phenix.bnl.gov/phenix/WWW/info/data/ppg116_data.html>，描述：包含实验数据点的网页