AI 中文总结
研究在轻离子碰撞中 $Υ$(nS) 态的顺序抑制，通过测量氧-氧、氖-氖碰撞中相关共振态产率，发现 $Υ$(2S)/$Υ$(1S) 和 $Υ$(3S)/$Υ$(1S) 比值下降，为轻离子碰撞中 $Υ$(nS) 态顺序抑制提供证据。
AI 中文摘要
重夸克-反夸克对的束缚态，即夸克偶素，长期以来被视为夸克-胶子等离子体（QGP）的特别敏感探针。通过比较重核（如金或铅）碰撞中夸克偶素的产率与质子-质子（pp）参考值，揭示了顺序抑制的特征模式，其中弱束缚激发态比基态受到更强抑制。我们报告了在每核子对质心能量 $\sqrt{s_\mathrm{NN}}$ = 5.36 TeV 的氧-氧碰撞中，对三个最低质量的 S 波矢量底夸克偶素共振态，即基态 $Υ$(1S) 和激发态 $Υ$(2S)、$Υ$(3S) 的首次测量。还展示了在相同 $\sqrt{s_\mathrm{NN}}$ 下氖-氖碰撞中 $Υ$(1S) 和 $Υ$(2S) 共振态产率的测量结果。发现 $Υ$(2S)/$Υ$(1S) 比值显著低于测量的 pp 参考值，$Υ$(3S)/$Υ$(1S) 比值下降更大。$Υ$(3S) 相对于 $Υ$(2S) 抑制的显著性超过三个标准差。这些结果为轻离子碰撞中 $Υ$(nS) 态的顺序抑制提供了证据，类似于在铅-铅和金-金碰撞中的观察结果，通常归因于 QGP 介质的存在。
英文摘要
Bound states of heavy quark-antiquark pairs, known as quarkonia, have long been regarded as particularly sensitive probes of the quark-gluon plasma (QGP). Comparing quarkonium yields in collisions of heavy nuclei, such as gold or lead, with a proton-proton (pp) reference reveals a characteristic pattern of sequential suppression, in which weakly-bound excited states are more strongly suppressed than the ground states. We report the first measurements of the three lowest mass $\mathrm{S}$-wave vector bottomonium resonances, the ground state $Υ$(1S) and the excited states $Υ$(2S) and $Υ$(3S), in oxygen-oxygen collisions at a center-of-mass energy per nucleon pair of $\sqrt{s_\mathrm{NN}}$ = 5.36 TeV. Measurements of the yields of the $Υ$(1S) and $Υ$(2S) resonances in neon-neon collisions, at the same $\sqrt{s_\mathrm{NN}}$, are also presented. The $Υ$(2S)/$Υ$(1S) ratio is found to be significantly below the measured pp reference value, and the $Υ$(3S)/$Υ$(1S) ratio shows an even larger reduction. The significance of the relative $Υ$(3S) to $Υ$(2S) suppression exceeds three standard deviations. These results provide evidence for the sequential suppression of $Υ$(nS) states in light ion collisions, similar to observations made in lead-lead and gold-gold collisions, generally attributed to the presence of a QGP medium.
CommentsThis version has an updated author list. Submitted to Physical Review Letters. All figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/HIN-25-015 (CMS Public Pages)
