"Table 6" of "Measurement of jet quenching with semi-inclusive hadron-jet distributions in central Pb-Pb collisions at ${\sqrt{\bf{s}_{\mathrm {\bf{NN}}}}}$ = 2.76 TeV"

CERN-LHC. We report the measurement of a new observable of jet quenching in central Pb-Pb collisions at $\sqrt{s_{\rm NN}} = 2.76$ TeV, based on the semi-inclusive rate of charged jets recoiling from a high transverse momentum (high-$p_{\rm T}$) charged hadron trigger. Jets are measured using collinear-safe jet reconstruction with infrared cutoff for jet constituents of 0.15 GeV/$c$, for jet resolution parameters $R = 0.2$, 0.4 and 0.5. Underlying event background is corrected at the event-ensemble level, without imposing bias on the jet population. Recoil jet spectra are reported in the range $20 < p_\mathrm{T,jet}^\mathrm{ch} < 100$ GeV/$c$. Reference distributions for pp collisions at $\sqrt{s} = 2.76$ TeV are calculated using Monte Carlo and NLO pQCD methods, which are validated by comparing with measurements in pp collisions at $\sqrt{s} = 7$ TeV. The recoil jet yield in central Pb-Pb collisions is found to be suppressed relative to that in pp collisions. No significant medium-induced broadening of the intra-jet energy profile is observed within 0.5 radians relative to the recoil jet axis. The angular distribution of the recoil jet yield relative to the trigger axis is found to be similar in central Pb-Pb and pp collisions, with no significant medium-induced acoplanarity observed. Large-angle jet deflection, which may provide a direct probe of the nature of the quasi-particles in hot QCD matter, is explored.

欧洲核子研究中心大型强子对撞机（CERN-LHC）：本文报道了一项针对核子-核子质心系能量$sqrt{s_{
m NN}} = 2.76$ TeV的中心铅铅碰撞中喷注淬火新可观测量的测量工作，该测量基于以高横动量（high-$p_{
m T}$）带电强子为触发粒子的反冲带电喷注的半单举产率。喷注的测量采用共线安全的喷注重建方法，对喷注组成粒子设置0.15 GeV/$c$的红外截断，并选取喷注分辨参数$R = 0.2、0.4$和$0.5$。我们在事件系综层面完成对伴随事件背景的修正，且未对喷注样本引入选择偏倚。反冲带电喷注的横动量谱测量范围为$20 < p_{
m T,jet}^{
m ch} < 100$ GeV/$c$。针对$sqrt{s} = 2.76$ TeV的质子-质子（pp）碰撞，我们采用蒙特卡洛（Monte Carlo）与次领头阶微扰量子色动力学（NLO pQCD）方法计算其参考分布，并通过与$sqrt{s} = 7$ TeV质子-质子碰撞的测量结果比对验证了该计算方法的有效性。研究发现，中心铅铅碰撞中的反冲喷注产率相较于质子-质子碰撞出现了抑制。在反冲喷注轴线0.5弧度范围内，未观测到由介质诱导产生的喷注内部能量分布显著展宽。相较于触发粒子轴线，反冲喷注产率的角分布在中心铅铅碰撞与质子-质子碰撞中表现出相似性，且未观测到显著的由介质诱导产生的非共面性。本研究还探讨了大角度喷注偏转现象，该现象可作为探测热量子色动力学（QCD）物质中准粒子本质的直接探针。