Centrality dependence of low-momentum direct-photon production in Au + Au collisions at √sNN = 200 GeV

Adare, A. and Makek, Mihael and Zolin, L. (PHENIX Collaboration) (2015) Centrality dependence of low-momentum direct-photon production in Au + Au collisions at √sNN = 200 GeV. Physical Review C, 91 (6). pp. 64904-11. ISSN 0556-2813

[img]
Preview
PDF - Published Version
Language: English

Download (1MB) | Preview

Abstract

The PHENIX experiment at RHIC has measured the centrality dependence of the direct photon yield from Au + Au collisions at √sNN = 200 GeV down to p_T = 0.4 GeV/c. Photons are detected via photon conversions to e+e− pairs and an improved technique is applied that minimizes the systematic uncertainties that usually limit direct photon measurements, in particular at low p_T . We find an excess of direct photons above the N_coll-scaled yield measured in p + p collisions. This excess yield is well described by an exponential distribution with an inverse slope of about 240 MeV/c in the p_T range 0.6–2.0 GeV/c. While the shape of the pT distribution is independent of centrality within the experimental uncertainties, the yield increases rapidly with increasing centrality, scaling approximately with N^α_part, where α = 1.38 ± 0.03(stat) ± 0.07(syst).

Item Type: Article
Date: 5 June 2015
Subjects: NATURAL SCIENCES > Physics > Nuclear Physics
Additional Information: Copyright (2015) by the American Physical Society.
Divisions: Faculty of Science > Department of Physics
Publisher: American Physical Society
Depositing User: Gordana Stubičan Ladešić
Date Deposited: 11 Jun 2015 10:25
Last Modified: 11 Jun 2015 10:25
URI: http://digre.pmf.unizg.hr/id/eprint/4041

Actions (login required)

View Item View Item