The production of ϒ mesons in Pb–Pb collisions at a centre-of-mass energy per nucleon pair $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV is measured with the muon spectrometer of the ALICE detector at the LHC. The yields as well as the nuclear modification factors are determined in the forward rapidity region $2.5<y<4.0$, as a function of rapidity, transverse momentum and collision centrality. The results show that the production of the $\mathrm{\Upsilon }(\mathrm{1S})$ meson is suppressed by a factor of about three with respect to the production in proton–proton collisions. For the first time, a significant signal for the $\mathrm{\Upsilon }(\mathrm{2S})$ meson is observed at forward rapidity, indicating a suppression stronger by about a factor 2–3 with respect to the ground state. The measurements are compared with transport, hydrodynamic, comover and statistical hadronisation model calculations.

在每个核子对的质心能量下 Pb-Pb 碰撞中产生 ϒ 介子 $\sqrt{{秒}_{\mathrm{神经网络}}}=5.02$TeV 是用 LHC 上的 ALICE 探测器的 μ 子光谱仪测量的。产率和核修饰因子在前进速度区确定$2.5<是<4.0$，作为速度、横向动量和碰撞中心性的函数。结果表明，生产$\mathrm{⒈}(\mathrm{1秒})$就质子-质子碰撞的产生而言，介子被抑制了大约三倍。首次向市场发出重要信号$\mathrm{⒈}(\mathrm{2S})$以向前的速度观察到介子，这表明相对于基态的抑制强了大约 2-3 倍。将测量结果与传输、流体动力学、comover 和统计强子化模型计算进行比较。