Measurement of prompt J/psi and beauty hadron production cross sections at mid-rapidity in pp collisions at root s=7 TeV
Alme, Johan; Erdal, Hege Austrheim; Helstrup, Håvard; Hetland, Kristin Fanebust; Kileng, Bjarte; Altinpinar, Sedat; Djuvsland, Øystein; Fehlker, Dominik; Haaland, Øystein Senneset; Huang, Meidana; Kanaki, Kalliopi; Langøy, Rune; Lien, Jørgen; Liu, Lijiao; Lønne, Per-Ivar; Nystrand, Joakim; Røed, Ketil; Røhrich, Dieter; Skjerdal, Kyrre; Szostak, Artur Krzysztof; Ullaland, Kjetil; Øvrebekk, Gaute; 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; Abelev, Betty; Abrahantes Quintana, Arian; Adam, Jaroslav; Adamová, Dagmar; Adare, Andrew Marshall; Aggarwal, Madan M.; Aglieri Rinella, Gianluca; Agocs, Andreas Gabor; Agostinelli, Andrea; Aguilar Salazar, Saul; Ahammed, Zubayer; Ahmad, Nazeer; Ahmad Masoodi, Arshar; Ahn, Sang Un
Peer reviewed, Journal article
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The ALICE experiment at the LHC has studied J/ψ production at mid-rapidity in pp collisions at s√=7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity Lint = 5.6 nb−1. The fraction of J/ψ from the decay of long-lived beauty hadrons was determined for J/ψ candidates with transverse momentum pt> 1.3 GeV/c and rapidity |y| < 0.9. The cross section for prompt J/ψ mesons, i.e. directly produced J/ψ and prompt decays of heavier charmonium states such as the ψ(2S) and χc resonances, is σprompt J/ψ (pt> 1.3 GeV/c, |y| < 0.9) = 8.3 ± 0.8 (stat.) ± 1.1 (syst.) +1.5−1.4 (syst. pol.) μb. The cross section for the production of b-hadrons decaying to J/ψ with pt> 1.3 GeV/c and |y| < 0.9 is σJ/ψ←hB (pt > 1.3 GeV/c, |y| < 0.9) = 1.46 ± 0.38 (stat.) +0.26−0.32 (syst.) μb. The results are compared to QCD model predictions. The shape of the pt and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the bb¯¯¯ pair total cross section and dσ/dy at mid-rapidity.
JournalJournal of High Energy Physics
Journal of High Energy Physics (JHEP)