In:
Journal of High Energy Physics, Springer Science and Business Media LLC, Vol. 2020, No. 9 ( 2020-09)
Abstract:
Systematic studies of charge-dependent two- and three-particle correlations in Pb-Pb collisions at $$ \sqrt{s_{\mathrm{NN}}} $$ s NN = 2.76 and 5.02 TeV used to probe the Chiral Magnetic Effect (CME) are presented. These measurements are performed for charged particles in the pseudorapidity ( η ) and transverse momentum ( p T ) ranges | η | 〈 0 . 8 and 0 . 2 〈 p T 〈 5 GeV/ c . A significant charge-dependent signal that becomes more pronounced for peripheral collisions is reported for the CME-sensitive correlators γ 1, 1 = 〈cos( φ α + φ β − 2Ψ 2 )〉 and γ 1, − 3 = 〈cos( φ α − 3 φ β + 2Ψ 2 )〉. The results are used to estimate the contribution of background effects, associated with local charge conservation coupled to anisotropic flow modulations, to measurements of the CME. A blast-wave parametrisation that incorporates local charge conservation tuned to reproduce the centrality dependent background effects is not able to fully describe the measured γ 1 , 1 . Finally, the charge and centrality dependence of mixed-harmonics three-particle correlations, of the form γ 1, 2 = 〈cos( φ α + 2 φ β − 3Ψ 3 )〉, which are insensitive to the CME signal, verify again that background contributions dominate the measurement of γ 1 , 1 .
Type of Medium:
Online Resource
ISSN:
1029-8479
DOI:
10.1007/JHEP09(2020)160
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
2020
detail.hit.zdb_id:
2027350-2
