Title
Direct photon production in Pb–Pb collisions at √sNN=2.76 TeV
Date Issued
10 March 2016
Access level
open access
Resource Type
journal article
Author(s)
Adam J.
Adamová D.
Aggarwal M.M.
Aglieri Rinella G.
Agnello M.
Agrawal N.
Ahammed Z.
Ahn S.U.
Aiola S.
Akindinov A.
Alam S.N.
Aleksandrov D.
Alessandro B.
Alexandre D.
Alfaro Molina R.
Alici A.
Alkin A.
Almaraz J.R.M.
Alme J.
Alt T.
Altinpinar S.
Altsybeev I.
Alves Garcia Prado C.
Andrei C.
Andronic A.
Anguelov V.
Anielski J.
Antičić T.
Antinori F.
Antonioli P.
Aphecetche L.
Appelshäuser H.
Arcelli S.
Arnaldi R.
Arnold O.W.
Arsene I.C.
Arslandok M.
Audurier B.
Augustinus A.
Averbeck R.
Awes T.C.
Azmi M.D.
Badalà A.
Baek Y.W.
Bagnasco S.
Bailhache R.
Bala R.
Baldisseri A.
Baral R.C.
Barbano A.M.
Barbera R.
Barile F.
Barnaföldi G.G.
Barnby L.S.
Barret V.
Bartalini P.
Barth K.
Bartke J.
Bartsch E.
Basile M.
Bastid N.
Basu S.
Bathen B.
Batigne G.
Batista Camejo A.
Batyunya B.
Batzing P.C.
Bearden I.G.
Beck H.
Bedda C.
Behera N.K.
Belikov I.
Bellini F.
Bello Martinez H.
Bellwied R.
Belmont R.
Belmont-Moreno E.
Belyaev V.
Bencedi G.
Beole S.
Berceanu I.
Bercuci A.
Berdnikov Y.
Berenyi D.
Bertens R.A.
Berzano D.
Betev L.
Bhasin A.
Bhat I.R.
Bhati A.K.
Bhattacharjee B.
Bhom J.
Bianchi L.
Bianchi N.
Bianchin C.
Bielčík J.
Bielčíková J.
Bilandzic A.
Biswas R.
Biswas S.
Publisher(s)
Elsevier B.V.
Abstract
Direct photon production at mid-rapidity in Pb–Pb collisions at sNN=2.76 TeV was studied in the transverse momentum range 0.9<pT<14 GeV/c. Photons were detected with the highly segmented electromagnetic calorimeter PHOS and via conversions in the ALICE detector material with the e+e− pair reconstructed in the central tracking system. The results of the two methods were combined and direct photon spectra were measured for the 0–20%, 20–40%, and 40–80% centrality classes. For all three classes, agreement was found with perturbative QCD calculations for pT≳5 GeV/c. Direct photon spectra down to pT≈1 GeV/c could be extracted for the 20–40% and 0–20% centrality classes. The significance of the direct photon signal for 0.9<pT<2.1 GeV/c is 2.6σ for the 0–20% class. The spectrum in this pT range and centrality class can be described by an exponential with an inverse slope parameter of (297±12stat±41syst) MeV. State-of-the-art models for photon production in heavy-ion collisions agree with the data within uncertainties.
Start page
235
End page
248
Volume
754
Language
English
OCDE Knowledge area
Química física
Electroquímica
Scopus EID
2-s2.0-85040813298
Source
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
ISSN of the container
03702693
Sponsor(s)
National Science Foundation 1307461, 1407051
Science and Technology Facilities Council 2014 STFC Nuclear Physics CG, ALICE, GRIDPP, ST/J000108/1, ST/L005670/1, ST/L005689/1, ST/L005751/1, ST/M00158X/1, ST/M001598/1, ST/M001601/1
Japan Society for the Promotion of Science 15H03664, 25287048, 26220707, 26610071
Sources of information:
Directorio de Producción Científica
Scopus