Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions

(PHENIX Collaboration)

doi:10.1103/PhysRevLett.123.022301

Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions

(PHENIX Collaboration)

Research output: Contribution to journal › Article › peer-review

36 Citations (Scopus)

Abstract

The PHENIX collaboration presents first measurements of low-momentum (0.4<pT<3 GeV/c) direct-photon yields from Au+Au collisions at sNN=39 and 62.4 GeV. For both beam energies the direct-photon yields are substantially enhanced with respect to expectations from prompt processes, similar to the yields observed in Au+Au collisions at sNN=200. Analyzing the photon yield as a function of the experimental observable dNch/dη reveals that the low-momentum (>1 GeV/c) direct-photon yield dNγdir/dη is a smooth function of dNch/dη and can be well described as proportional to (dNch/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 pT (>5 GeV/c), but when results from different collision energies are compared, an additional sNN-dependent multiplicative factor is needed to describe the integrated-direct-photon yield.

Original language	English
Article number	022301
Journal	Physical review letters
Volume	123
Issue number	2
DOIs	https://doi.org/10.1103/PhysRevLett.123.022301
Publication status	Published - 2019 Jul 10

Bibliographical note

Publisher Copyright:
© 2019 authors. Published by the American Physical Society.

ASJC Scopus subject areas

General Physics and Astronomy

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10.1103/PhysRevLett.123.022301

Cite this

@article{e1359b3572b141b1861c0284d1c29507,

title = "Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions",

abstract = "The PHENIX collaboration presents first measurements of low-momentum (0.41 GeV/c) direct-photon yield dNγdir/dη is a smooth function of dNch/dη and can be well described as proportional to (dNch/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 pT (>5 GeV/c), but when results from different collision energies are compared, an additional sNN-dependent multiplicative factor is needed to describe the integrated-direct-photon yield.",

author = "{(PHENIX Collaboration)} and A. Adare and S. Afanasiev and C. Aidala and Ajitanand, {N. N.} and Y. Akiba and R. Akimoto and H. Al-Bataineh and J. Alexander and M. Alfred and A. Al-Jamel and H. Al-Ta'Ani and A. Angerami and K. Aoki and N. Apadula and L. Aphecetche and Y. Aramaki and R. Armendariz and Aronson, {S. H.} and J. Asai and H. Asano and Aschenauer, {E. C.} and Atomssa, {E. T.} and R. Averbeck and Awes, {T. C.} and B. Azmoun and V. Babintsev and A. Bagoly and M. Bai and G. Baksay and L. Baksay and A. Baldisseri and B. Bannier and Barish, {K. N.} and Barnes, {P. D.} and B. Bassalleck and Basye, {A. T.} and S. Bathe and S. Batsouli and V. Baublis and F. Bauer and C. Baumann and S. Baumgart and A. Bazilevsky and S. Belikov and R. Belmont and R. Bennett and A. Berdnikov and B. Hong and Park, {S. K.} and Yoo, {J. H.}",

note = "Publisher Copyright: {\textcopyright} 2019 authors. Published by the American Physical Society.",

year = "2019",

month = jul,

day = "10",

doi = "10.1103/PhysRevLett.123.022301",

language = "English",

volume = "123",

journal = "Physical review letters",

issn = "0031-9007",

publisher = "American Physical Society",

number = "2",

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TY - JOUR

T1 - Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions

AU - (PHENIX Collaboration)

AU - Adare, A.

AU - Afanasiev, S.

AU - Aidala, C.

AU - Ajitanand, N. N.

AU - Akiba, Y.

AU - Akimoto, R.

AU - Al-Bataineh, H.

AU - Alexander, J.

AU - Alfred, M.

AU - Al-Jamel, A.

AU - Al-Ta'Ani, H.

AU - Angerami, A.

AU - Aoki, K.

AU - Apadula, N.

AU - Aphecetche, L.

AU - Aramaki, Y.

AU - Armendariz, R.

AU - Aronson, S. H.

AU - Asai, J.

AU - Asano, H.

AU - Aschenauer, E. C.

AU - Atomssa, E. T.

AU - Averbeck, R.

AU - Awes, T. C.

AU - Azmoun, B.

AU - Babintsev, V.

AU - Bagoly, A.

AU - Bai, M.

AU - Baksay, G.

AU - Baksay, L.

AU - Baldisseri, A.

AU - Bannier, B.

AU - Barish, K. N.

AU - Barnes, P. D.

AU - Bassalleck, B.

AU - Basye, A. T.

AU - Bathe, S.

AU - Batsouli, S.

AU - Baublis, V.

AU - Bauer, F.

AU - Baumann, C.

AU - Baumgart, S.

AU - Bazilevsky, A.

AU - Belikov, S.

AU - Belmont, R.

AU - Bennett, R.

AU - Berdnikov, A.

AU - Hong, B.

AU - Park, S. K.

AU - Yoo, J. H.

PY - 2019/7/10

Y1 - 2019/7/10

N2 - The PHENIX collaboration presents first measurements of low-momentum (0.41 GeV/c) direct-photon yield dNγdir/dη is a smooth function of dNch/dη and can be well described as proportional to (dNch/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 pT (>5 GeV/c), but when results from different collision energies are compared, an additional sNN-dependent multiplicative factor is needed to describe the integrated-direct-photon yield.

AB - The PHENIX collaboration presents first measurements of low-momentum (0.41 GeV/c) direct-photon yield dNγdir/dη is a smooth function of dNch/dη and can be well described as proportional to (dNch/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 pT (>5 GeV/c), but when results from different collision energies are compared, an additional sNN-dependent multiplicative factor is needed to describe the integrated-direct-photon yield.

UR - http://www.scopus.com/inward/record.url?scp=85069921283&partnerID=8YFLogxK

U2 - 10.1103/PhysRevLett.123.022301

DO - 10.1103/PhysRevLett.123.022301

M3 - Article

C2 - 31386493

AN - SCOPUS:85069921283

SN - 0031-9007

VL - 123

JO - Physical review letters

JF - Physical review letters

IS - 2

M1 - 022301

ER -

Beam Energy and Centrality Dependence of Direct-Photon Emission from Ultrarelativistic Heavy-Ion Collisions

Abstract

Bibliographical note

ASJC Scopus subject areas

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