Charmonium and \(e^+e^-\) pair photoproduction at mid-rapidity in ultra-peripheral Pb-Pb collisions at \(\sqrt{s_{NN}}\) = 2.76 TeV
Alme, Johan; Erdal, Hege Austrheim; Helstrup, Håvard; Hetland, Kristin Fanebust; Kileng, Bjarte; Altinpinar, Sedat; Djuvsland, Øystein; Fehlker, Dominik; Haaland, Øystein Senneset; Huang, Meidana; Langøy, Rune; Lien, Jørgen; Lønne, Per-Ivar; Nystrand, Joakim; Rehman, Attiq ur; Røed, Ketil; Røhrich, Dieter; Skjerdal, Kyrre; Ullaland, Kjetil; Wagner, Boris; Yang, Shiming; Dordic, Olja; Eyyubova, Gyulnara; Kværnø, Henning; Lindal, Svein; Løvhøiden, Gunnar; Milosevic, Jovan; Nilsson, Mads Stormo; Qvigstad, Henrik; Richter, Matthias; Skaali, Toralf Bernhard; Tveter, Trine Spedstad; Wikne, Jon Christopher; Abbas, Eham Gamal; Abelev, Betty; Adam, Jaroslav; Adamová, Dagmar; Adare, Andrew Marshall; Aggarwal, Madan M.; Aguilar Salazar, Saul; Ahammed, Zubayer; Ahmad, Nazeer; Ahmad Masoodi, Arshar; Ahn, Sang Un; Ajaz, Muhammad; Akindinov, Alexander; Aleksandrov, Dimitry; Alessandro, Bruno; Alici, Andrea; Alkin, Anton; ALICE, Collaboration
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2013-11Metadata
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Alme J, Erdal HA, Helstrup H, Hetland KF, Kileng B, Altinpinar S, Djuvsland Ø, Fehlker D, Haaland ØS, Huang M, Langøy R, Lien JA, Lønne P, Nystrand J, Rehman Au, Røed K, Røhrich D, Skjerdal K, Ullaland K, Wagner B, Yang S, Dordic O, Eyyubova G, Kværnø H, Lindal S, Løvhøiden G, Milosevic J, Nilsson MS, Qvigstad H, Richter M, Skaali TB, Tveter TS, Wikne JC, Abbas EG, Abelev B, Adam J, Adamová D, Adare AM, Aggarwal MM, Aguilar Salazar S, Ahammed Z, Ahmad N, Ahmad Masoodi A, Ahn SU, Ajaz, Akindinov A, Aleksandrov D, Alessandro B, Alici A, Alkin A, ALICE C. Charmonium and e(+)e(-) pair photoproduction at mid-rapidity in ultra-peripheral Pb-Pb collisions at root s(NN)=2.76 TeV. European Physical Journal C. 2013;73:2617 https://doi.org/10.1140/epjc/s10052-013-2617-1Abstract
The ALICE Collaboration at the LHC has measured the \(J/\psi\) and \(\psi\)' photoproduction at mid-rapidity in ultra-peripheral Pb-Pb collisions at \(\sqrt{s_{NN}}\) = 2.76 TeV. The charmonium is identified via its leptonic decay for events where the hadronic activity is required to be minimal. The analysis is based on an event sample corresponding to an integrated luminosity of about 23 \({\mu}b^{-1}\), The cross section for coherent and incoherent \(J/\psi\) production in the rapidity interval -0.9 < y < 0.9, are \(d\sigma_{J/\psi}^{coh}/dy = 2.38^{+0.34}_{-0.24}(sta+sys)\) mb and \(d\sigma_{J/\psi}^{inc}/dy = 0.98^{+0.19}_{-0.17}(sta+sys)\) mb, respectively. The results are compared to theoretical models for \(J/\psi\) production and the coherent cross section is found to be in good agreement with those models which include nuclear gluon shadowing consistent with EPS09 parametrization. In addition the cross section for the process \(\gamma\gamma \to e^+e^-\) has been measured and found to be in agreement with the STARLIGHT Monte Carlo predictions.