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Author(s) |
Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Chudasama, R.; Dutta, D.; Jha, V.; V. Kumar; Mohanty, A. K.; Netrakanti, P. K.; Pant, L. M.; Shukla, P.; Topkar, A.; and others (PG)
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Source |
Physics Letters-B, 2017. Vol. 765: pp. 193-220 |
ABSTRACT
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Measurements of two-and multi-particle angular correlations in pp collisions at √s = 5, 7,and13 TeVare presented as a function of charged-particle multiplicity. The data, corresponding to integrated luminosities of 1.0 pb−1 (5TeV), 6.2 pb−1 (7TeV), and 0.7 pb−1(13 TeV), were collected using the CMS detector at the LHC. The second-order (v2) and third-order (v3) azimuthal anisotropy harmonics of unidentified charged particles, as well as v2 of K0S and Λ/Λ¯ 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 v2 values of charged hadrons (mostly pions), K0S, and Λ/Λ¯, with lighter particle species exhibiting a stronger azimuthal anisotropy signal below pT ≈ 2 GeV/c. For 13 TeV data, the v2 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. |
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