e-Article
Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions
Document Type
article
Author
Adare, A; Afanasiev, S; Aidala, C; Ajitanand, NN; Akiba, Y; Akimoto, R; Al-Bataineh, H; Alexander, J; Alfred, M; Al-Jamel, A; Al-Ta'ani, H; Angerami, A; Aoki, K; Apadula, N; Aphecetche, L; Aramaki, Y; Armendariz, R; Aronson, SH; Asai, J; Asano, H; Aschenauer, EC; Atomssa, ET; Averbeck, R; Awes, TC; Azmoun, B; Babintsev, V; Bagoly, A; Bai, M; Baksay, G; Baksay, L; Baldisseri, A; Bannier, B; Barish, KN; Barnes, PD; Bassalleck, B; Basye, AT; Bathe, S; Batsouli, S; Baublis, V; Bauer, F; Baumann, C; Baumgart, S; Bazilevsky, A; Belikov, S; Belmont, R; Bennett, R; Berdnikov, A; Berdnikov, Y; Bhom, JH; Bickley, AA; Bjorndal, MT; Blau, DS; Boer, M; Boissevain, JG; Bok, JS; Borel, H; Boyle, K; Brooks, ML; Brown, DS; Bryslawskyj, J; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, JM; Butsyk, S; Camacho, CM; Campbell, S; Canoa Roman, V; Caringi, A; Castera, P; Chai, J-S; Chang, BS; Chang, WC; Charvet, J-L; Chen, C-H; Chernichenko, S; Chi, CY; Chiba, J; Chiu, M; Choi, IJ; Choi, JB; Choi, S; Choudhury, RK; Christiansen, P; Chujo, T; Chung, P; Churyn, A; Chvala, O; Cianciolo, V; Citron, Z; Cleven, CR; Cobigo, Y; Cole, BA; Comets, MP; Conesa Del Valle, Z; Connors, M; Constantin, P; Csanád, M; Csörgő, T
Source
Physical Review Letters. 123(2)
Subject
Language
Abstract
The PHENIX collaboration presents first measurements of low-momentum (0.41 GeV/c) direct-photon yield dN_{γ}^{dir}/dη is a smooth function of dN_{ch}/dη and can be well described as proportional to (dN_{ch}/dη)^{α} with α≈1.25. This scaling behavior holds for a wide range of beam energies at the Relativistic Heavy Ion Collider and the Large Hadron Collider, for centrality selected samples, as well as for different A+A collision systems. At a given beam energy, the scaling also holds for high p_{T} (>5 GeV/c), but when results from different collision energies are compared, an additional sqrt[s_{NN}]-dependent multiplicative factor is needed to describe the integrated-direct-photon yield.