AGH University of Science and Technology, FPACS, Cracow 30-059, Poland.
Ohio State University, Columbus, Ohio 43210, USA.
Phys Rev Lett. 2018 Jul 20;121(3):032301. doi: 10.1103/PhysRevLett.121.032301.
We report measurements of the nuclear modification factor R_{CP} for charged hadrons as well as identified π^{+(-)}, K^{+(-)}, and p(p[over ¯]) for Au+Au collision energies of sqrt[s_{NN}]=7.7, 11.5, 14.5, 19.6, 27, 39, and 62.4 GeV. We observe a clear high-p_{T} net suppression in central collisions at 62.4 GeV for charged hadrons which evolves smoothly to a large net enhancement at lower energies. This trend is driven by the evolution of the pion spectra but is also very similar for the kaon spectra. While the magnitude of the proton R_{CP} at high p_{T} does depend on the collision energy, neither the proton nor the antiproton R_{CP} at high p_{T} exhibit net suppression at any energy. A study of how the binary collision-scaled high-p_{T} yield evolves with centrality reveals a nonmonotonic shape that is consistent with the idea that jet quenching is increasing faster than the combined phenomena that lead to enhancement.
我们报告了在 Au+Au 碰撞能量为 sqrt[s_{NN}]=7.7、11.5、14.5、19.6、27、39 和 62.4 GeV 时,带电强子以及分辨出的 π^{+(-)}、K^{+(-)}和 p(p[over ¯])的核修正因子 R_{CP}的测量结果。我们观察到在 62.4 GeV 的中心碰撞中,带电强子存在明显的高-p_{T}净抑制,这种抑制在较低能量下平滑地演变为大的净增强。这种趋势是由π谱的演化驱动的,但对于 K 谱也是非常相似的。虽然质子在高 p_{T}的 R_{CP}的大小确实取决于碰撞能量,但在任何能量下,质子和反质子在高 p_{T}都没有净抑制。对二进制碰撞标度的高-p_{T}产额如何随中心度演化的研究揭示了一种非单调形状,这与喷注淬火比导致增强的综合现象增长更快的观点一致。