Observation of centrality-dependent acoplanarity for muon pairs produced via two-photon scattering in Pb+Pb collisions at √sNN=5.02 TeV with the ATLAS detector

Abraham, N L, Allbrooke, B M M, Asquith, L, Cerri, A, Jones, S D, De Santo, A, Salvatore, F, Shaw, K, Stevenson, T J, Suruliz, K, Sutton, M R, Tresoldi, F, Trovato, F, Vivarelli, I, Winkels, E, The ATLAS Collaboration, and others, (2018) Observation of centrality-dependent acoplanarity for muon pairs produced via two-photon scattering in Pb+Pb collisions at √sNN=5.02 TeV with the ATLAS detector. Physical Review Letters, 121 (21). a212301 1-21. ISSN 0031-9007

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Abstract

This Letter presents a measurement of γγ→μ+μ− production in Pb+Pb collisions recorded by the ATLAS detector at the Large Hadron Collider at √sNN=5.02 TeV with an integrated luminosity of 0.49 nb−1. The azimuthal angle and transverse momentum correlations between the muons are measured as a function of collision centrality. The muon pairs are produced from γγ through the interaction of the large electromagnetic fields of the nuclei. The contribution from background sources of muon pairs is removed using a template fit method. In peripheral collisions, the muons exhibit a strong back-to-back correlation consistent with previous measurements of muon pair production in ultraperipheral collisions. The angular correlations are observed to broaden significantly in central collisions. The modifications are qualitatively consistent with rescattering of the muons while passing through the hot matter produced in the collision.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
Subjects: Q Science > QC Physics
Depositing User: Amelia Redman
Date Deposited: 19 Sep 2019 14:13
Last Modified: 19 Sep 2019 14:15
URI: http://sro.sussex.ac.uk/id/eprint/85923

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