A1 Journal article (refereed)
Longitudinal and azimuthal evolution of two-particle transverse momentum correlations in Pb–Pb collisions at √sNN = 2.76 TeV (2020)

ALICE Collaboration. (2020). Longitudinal and azimuthal evolution of two-particle transverse momentum correlations in Pb–Pb collisions at √sNN = 2.76 TeV. Physics Letters B, 804, Article 135375. https://doi.org/10.1016/j.physletb.2020.135375

JYU authors or editors

Publication details

All authors or editors: ALICE Collaboration

Journal or series: Physics Letters B

ISSN: 0370-2693

eISSN: 1873-2445

Publication year: 2020

Volume: 804

Article number: 135375

Publisher: Elsevier

Publication country: Netherlands

Publication language: English

DOI: https://doi.org/10.1016/j.physletb.2020.135375

Publication open access: Openly available

Publication channel open access: Open Access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/68473

Web address of parallel published publication (pre-print): https://arxiv.org/abs/1910.14393

Abstract

This paper presents the first measurements of the charge independent (CI) and charge dependent (CD) two-particle transverse momentum correlators G2 CI and G2 CD in Pb–Pb collisions at sNN=2.76TeV by the ALICE collaboration. The two-particle transverse momentum correlator G2 was introduced as a measure of the momentum current transfer between neighboring system cells. The correlators are measured as a function of pair separation in pseudorapidity (Δη) and azimuth (Δφ) and as a function of collision centrality. From peripheral to central collisions, the correlator G2 CI exhibits a longitudinal broadening while undergoing a monotonic azimuthal narrowing. By contrast, G2 CD exhibits a narrowing along both dimensions. These features are not reproduced by models such as HIJING and AMPT. However, the observed narrowing of the correlators from peripheral to central collisions is expected to result from the stronger transverse flow profiles produced in more central collisions and the longitudinal broadening is predicted to be sensitive to momentum currents and the shear viscosity per unit of entropy density η/s of the matter produced in the collisions. The observed broadening is found to be consistent with the hypothesized lower bound of η/s and is in qualitative agreement with values obtained from anisotropic flow measurements.

Keywords: particle physics

Contributing organizations

Ministry reporting: Yes

Reporting Year: 2020

JUFO rating: 2