氧-氧碰撞中利用奇异强子观测到重子产生增强现象
Observation of enhanced baryon production using strange hadrons in oxygen-oxygen collisions
AI总结：
该研究在质心能量5.36 TeV的氧-氧碰撞中，利用CMS探测器观测到重子产生增强，首次发现氧-氧碰撞中存在重子-介子增强，为QGP相关机制研究提供了新证据。
AI中文摘要：
超相对论重核碰撞会产生一种名为夸克-胶子等离子体（QGP）的高温退禁闭介质。在这类系统中，强子产生相对于质子-质子（pp）相互作用会发生显著改变。在强子横动量区间2 < p_T < 5 GeV内，集体径向流与夸克组合是导致这类改变的重要机制。尽管这些效应在铅等大离子碰撞中已得到充分证实，但较小离子产生的系统中是否存在此类效应尚不清楚。为解决这一问题，在质心能量每核子对5.36 TeV的氧-氧（OO）和pp碰撞中，测量了两种奇异强子K^0_S和Λ的p_T谱。测量利用大型强子对撞机（LHC）的CMS探测器完成，OO和pp数据集对应的积分亮度分别为6.8 nb⁻¹和1.1 pb⁻¹。研究发现，OO碰撞中K^0_S介子相对于pp碰撞的谱改变与包含式带电强子相似；相反，OO碰撞中Λ与K^0_S的截面比值相较于pp碰撞呈现出显著增强。该结果首次观测到OO碰撞中的重子-介子增强，表明退禁闭介质的形成，为理解奇异性、径向流和夸克组合在QGP中的作用提供了见解。
英文摘要：
A hot deconfined medium known as the quark-gluon plasma (QGP) is created in collisions of ultrarelativistic heavy nuclei. In these systems, hadron production is strongly modified relative to proton-proton (pp) interactions. In the hadron transverse momentum region 2 $\lt$ $p_\mathrm{T}$ $\lt$ 5 GeV, collective radial flow and quark coalescence are important mechanisms that can produce such modifications. While these effects are well-established for collisions of large ions, such as lead, it is unknown if they are present in systems produced using smaller ions. To address this question, the $p_\mathrm{T}$ spectra of two strange hadrons, K$^0_\mathrm{S}$ and $Λ$, are measured in oxygen-oxygen (OO) and pp collisions at a center-of-mass energy per nucleon pair of 5.36 TeV. The measurements are performed using the CMS detector at the LHC, and the OO and pp datasets correspond to integrated luminosities of 6.8 nb$^{-1}$ and 1.1 pb$^{-1}$, respectively. The spectral modification of K$^0_\mathrm{S}$ mesons in OO collisions relative to pp collisions is found to be similar to that of inclusive charged hadrons. Conversely, the $Λ$-to-K$^0_\mathrm{S}$ cross section ratio exhibits a pronounced enhancement in OO collisions when compared to pp collisions. The results provide the first observation of a baryon-to-meson enhancement in OO collisions and suggest the formation of a deconfined medium, offering insight into the roles of strangeness, radial flow, and quark coalescence in QGP.
