Direct photon production and flow at low transverse momenta in pp, p–Pb and Pb–Pb collisions

ALICE Collaboration

Direct photon production and flow at low transverse momenta in pp, p–Pb and Pb–Pb collisions

ALICE Collaboration

Relativistic Nuclear Physics

Research output: Contribution to journal › Conference article › peer-review

Abstract

Low transverse momentum direct photon measurements have been carried out by the ALICE experiment at the CERN LHC in small collision systems (pp, √s = 2.76 and 8 TeV and p–Pb, √s_NN = 5.02 TeV) as well as in heavy-ion collisions (Pb–Pb, √s_NN = 2.76 TeV). For the first time, also the multiplicity dependence of direct photon production was investigated in p–Pb collisions. Whereas in the small systems no significant thermal photon signal was observed, a ∼ 15% excess has been measured in central Pb–Pb collisions in the region of p_T < 3 GeV/c. A signal of prompt photon production at high transverse momentum consistent with binary scaling has been observed in all collision systems following NLO pQCD predictions. Direct photon flow has been measured in central and semi-central Pb–Pb collisions and found to be of similar size as the charged hadron and decay photon flow.

Original language	English
Journal	Proceedings of Science
Volume	345
State	Published - 2018
Event	2018 International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions, Hard Probes 2018 - Aix-Les-Bains, Savoie, France Duration: Sep 30 2018 → Oct 5 2018

Cite this

@article{7c0d5a851c444b0c8c942b5102d41c9b,

title = "Direct photon production and flow at low transverse momenta in pp, p–Pb and Pb–Pb collisions",

abstract = "Low transverse momentum direct photon measurements have been carried out by the ALICE experiment at the CERN LHC in small collision systems (pp, √s = 2.76 and 8 TeV and p–Pb, √sNN = 5.02 TeV) as well as in heavy-ion collisions (Pb–Pb, √sNN = 2.76 TeV). For the first time, also the multiplicity dependence of direct photon production was investigated in p–Pb collisions. Whereas in the small systems no significant thermal photon signal was observed, a ∼ 15\% excess has been measured in central Pb–Pb collisions in the region of pT < 3 GeV/c. A signal of prompt photon production at high transverse momentum consistent with binary scaling has been observed in all collision systems following NLO pQCD predictions. Direct photon flow has been measured in central and semi-central Pb–Pb collisions and found to be of similar size as the charged hadron and decay photon flow.",

author = "\{ALICE Collaboration\} and Nicolas Schmidt",

note = "Publisher Copyright: {\textcopyright} Copyright owned by the author(s) under the terms of the Creative Commons.; 2018 International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions, Hard Probes 2018 ; Conference date: 30-09-2018 Through 05-10-2018",

year = "2018",

language = "English",

volume = "345",

journal = "Proceedings of Science",

issn = "1824-8039",

publisher = "Sissa Medialab",

}

TY - JOUR

T1 - Direct photon production and flow at low transverse momenta in pp, p–Pb and Pb–Pb collisions

AU - ALICE Collaboration

AU - Schmidt, Nicolas

N1 - Publisher Copyright: © Copyright owned by the author(s) under the terms of the Creative Commons.

PY - 2018

Y1 - 2018

N2 - Low transverse momentum direct photon measurements have been carried out by the ALICE experiment at the CERN LHC in small collision systems (pp, √s = 2.76 and 8 TeV and p–Pb, √sNN = 5.02 TeV) as well as in heavy-ion collisions (Pb–Pb, √sNN = 2.76 TeV). For the first time, also the multiplicity dependence of direct photon production was investigated in p–Pb collisions. Whereas in the small systems no significant thermal photon signal was observed, a ∼ 15% excess has been measured in central Pb–Pb collisions in the region of pT < 3 GeV/c. A signal of prompt photon production at high transverse momentum consistent with binary scaling has been observed in all collision systems following NLO pQCD predictions. Direct photon flow has been measured in central and semi-central Pb–Pb collisions and found to be of similar size as the charged hadron and decay photon flow.

AB - Low transverse momentum direct photon measurements have been carried out by the ALICE experiment at the CERN LHC in small collision systems (pp, √s = 2.76 and 8 TeV and p–Pb, √sNN = 5.02 TeV) as well as in heavy-ion collisions (Pb–Pb, √sNN = 2.76 TeV). For the first time, also the multiplicity dependence of direct photon production was investigated in p–Pb collisions. Whereas in the small systems no significant thermal photon signal was observed, a ∼ 15% excess has been measured in central Pb–Pb collisions in the region of pT < 3 GeV/c. A signal of prompt photon production at high transverse momentum consistent with binary scaling has been observed in all collision systems following NLO pQCD predictions. Direct photon flow has been measured in central and semi-central Pb–Pb collisions and found to be of similar size as the charged hadron and decay photon flow.

UR - https://www.scopus.com/pages/publications/85072694561

M3 - Conference article

AN - SCOPUS:85072694561

SN - 1824-8039

VL - 345

JO - Proceedings of Science

JF - Proceedings of Science

T2 - 2018 International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collisions, Hard Probes 2018

Y2 - 30 September 2018 through 5 October 2018

ER -

Direct photon production and flow at low transverse momenta in pp, p–Pb and Pb–Pb collisions

Abstract

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