"Table 7" of "Evidence for collectivity in pp collisions at the LHC"

CERN-LHC. Measurements of two- and multi-particle angular correlations in pp collisions at sqrt(s) = 5, 7, and 13 TeV are presented as a function of charged-particle multiplicity. The data, corresponding to integrated luminosities of 1.0 inverse picobarn (5 TeV), 6.2 inverse picobarns (7 TeV), and 0.7 inverse picobarns (13 TeV), were collected using the CMS detector at the LHC. The second-order (v[2]) and third-order (v[3]) azimuthal anisotropy harmonics of unidentified charged particles, as well as v[2] of K0 short and Lambda/anti-Lambda particles, are extracted from long-range two-particle correlations as functions of particle multiplicity and transverse momentum. For high-multiplicity pp events, a mass ordering is observed for the v[2] values of charged hadrons (mostly pions), K0 short, and Lambda/anti-Lambda, with lighter particle species exhibiting a stronger azimuthal anisotropy signal below pt of about 2 GeV/c. For 13 TeV data, the v[2] signals are also extracted from four- and six-particle correlations for the first time in pp collisions, with comparable magnitude to those from two-particle correlations. These observations are similar to those seen in pPb and PbPb collisions, and support the interpretation of a collective origin for the observed long-range correlations in high-multiplicity pp collisions.

本数据集来自CERN-LHC合作组，报告了质心能量√s=5、7和13 TeV的质子-质子（pp）碰撞中，二粒子与多粒子角关联随带电粒子多重数的测量结果。所用数据采自大型强子对撞机（Large Hadron Collider, LHC）上的CMS（紧凑型μ子螺线管，Compact Muon Solenoid）探测器，对应积分亮度分别为：5 TeV时1.0 逆皮靶恩（pb⁻¹）、7 TeV时6.2 逆皮靶恩，13 TeV时0.7 逆皮靶恩。研究人员通过长程二粒子关联，提取了未识别带电粒子的二阶（v₂）与三阶（v₃）方位角各向异性谐波，以及短寿命中性K介子（K⁰_S）和Λ/反Λ重子的v₂信号，提取过程以粒子多重数与横向动量为自变量。在高多重数质子-质子碰撞事件中，带电强子（以π介子为主）、K⁰_S以及Λ/反Λ重子的v₂值呈现质量依赖规律：在横向动量约2 GeV/c以下时，粒子质量越轻，其方位角各向异性信号越强。针对13 TeV的实验数据，本研究首次在质子-质子碰撞中从四粒子与六粒子关联中提取了v₂信号，其信号强度与二粒子关联得到的结果相当。上述观测结果与质子-铅（pPb）及铅-铅（PbPb）碰撞中的已有观测一致，为高多重数质子-质子碰撞中长程关联的集体起源解释提供了实验支持。