Measurement of quarkonium production in proton–lead and proton–proton collisions at $5.02~\mathrm {TeV}$ with the ATLAS detector

• Main Author: ATLAS collaboration (2839 authors)
• Publication Date: 2018
• Other Authors: Aguilar-Saavedra, Juan Antonio, Amor Dos Santos, Susana Patricia, Anjos, Nuno, Araque, Juan Pedro, Carvalho, João, Castro, Nuno Filipe, Conde Muiño, Patricia, Da Cunha Sargedas De Sousa, Mario Jose, Fiolhais, Miguel, Galhardo, Bruno, Gomes, Agostinho, Gonçalo, Ricardo, Jorge, Pedro, Machado Miguens, Joana, Maio, Amélia, Maneira, José, Oleiro Seabra, Luis Filipe, Onofre, António, Pedro, Rute, Santos, Helena, Saraiva, João, Silva, José, Tavares Delgado, Ademar, Veloso, Filipe, Wolters, Helmut
• Format: Article
• Language: eng
• Source: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Download full: http://hdl.handle.net/10400.26/27437

The modification of the production of $J/\psi $ , $\psi (2\mathrm {S})$ , and $\varUpsilon (n\mathrm {S})$ ( $n = 1, 2, 3$ ) in p+Pb collisions with respect to their production in pp collisions has been studied. The p+Pb and pp datasets used in this paper correspond to integrated luminosities of $28~\mathrm {nb}^{-1}$ and $25~\mathrm {pb}^{-1}$ respectively, collected in 2013 and 2015 by the ATLAS detector at the LHC, both at a centre-of-mass energy per nucleon pair of 5.02 TeV. The quarkonium states are reconstructed in the dimuon decay channel. The yields of $J/\psi $ and $\psi (\mathrm {2S})$ are separated into prompt and non-prompt sources. The measured quarkonium differential cross sections are presented as a function of rapidity and transverse momentum, as is the nuclear modification factor, $R_{p\mathrm {Pb}}$ for $J/\psi $ and $\varUpsilon (n\mathrm {S})$ . No significant modification of the $J/\psi $ production is observed while $\varUpsilon (n\mathrm {S})$ production is found to be suppressed at low transverse momentum in p+Pb collisions relative to pp collisions. The production of excited charmonium and bottomonium states is found to be suppressed relative to that of the ground states in central p+Pb collisions.