AI 中文总结
本文利用ALICE探测器在轻离子碰撞中测量双强子关联近侧峰宽度，发现低横动量下OO和Ne--Ne碰撞的峰宽接近Pb--Pb，且现有模型无法完全重现实验结果。
AI 中文摘要
重离子碰撞主要用于研究热密核物质的性质，即夸克-胶子等离子体（QGP）。然而，最近在LHC的pp和p--Pb碰撞中观测到的类流体动力学行为表明，即使在小碰撞系统中也可能形成QGP液滴。为了弥合小系统与大系统之间的多重数差距，并检验流体动力学描述的适用性，2025年在LHC首次进行了轻离子碰撞。本文介绍了利用ALICE探测器在pO、OO和Ne--Ne碰撞中测量双强子关联的近侧峰宽度，用以搜寻介质效应。研究了近侧关联峰宽度随中心快度区平均带电粒子多重数的变化。在低横动量（$p_{\ m T}$）下，OO和Ne--Ne碰撞中的近侧峰比pp和pO碰撞中的更宽，并且在中心碰撞中其宽度接近Pb--Pb碰撞中测得的宽度。在较高$p_{\ m T}$下，峰宽随多重数增加而适度变窄。结果与PYTHIA、AMPT和JETSCAPE的计算进行了比较，这些计算均未能在整个运动学范围内重现所测得的宽度。
英文摘要
Heavy-ion collisions are primarily studied to investigate the properties of hot and dense nuclear matter, known as the quark--gluon plasma (QGP). However, recent observations of hydrodynamic flow-like behaviour in pp and p--Pb collisions at the LHC suggest the possible formation of QGP droplets even in small collision systems. To bridge the multiplicity gap between small and large systems and to examine the applicability of hydrodynamic descriptions, light-ion collisions were performed for the first time at the LHC in 2025. This contribution presents measurements of the near-side peak width of di-hadron correlations in pO, OO, and Ne--Ne collisions with ALICE, used to search for medium effects. The width of the near-side correlation peak is studied as a function of the average charged-particle multiplicity at midrapidity. At low transverse momentum ($p_{\rm T}$), the near-side peak is broader in OO and Ne--Ne collisions than in pp and pO collisions, and in central collisions its width approaches that measured in Pb--Pb collisions. At higher $p_{\rm T}$ the peak narrows modestly with increasing multiplicity. The results are compared with PYTHIA, AMPT, and JETSCAPE calculations, none of which reproduces the measured widths over the full kinematic range.
Comments3 pages, 8 figures, proceedings of 14th Edition of the Large Hadron Collider Physics (LHCP2026) conference, 18-22 May 2026, Paris, France
