Measurement of prompt and nonprompt $\mathrm{J}/{\psi }$ production in $\mathrm {p}\mathrm {p}$ and $\mathrm {p}\mathrm {Pb}$ collisions at $\sqrt{s_{\mathrm {NN}}} =5.02\,\text {TeV} $

• Main Author: CMS collaboration (2236 authors)
• Publication Date: 2017
• Other Authors: Nayak, Aruna, Bargassa, Pedrame, Beirão Da Cruz E Silva, Cristóvão, Calpas, Betty, Di Francesco, Agostino, Faccioli, Pietro, Ferreira Parracho, Pedro Guilherme, Gallinaro, Michele, Hollar, Jonathan, Leonardo, Nuno, Lloret Iglesias, Lara, Rodrigues Antunes, Joao, Seixas, Joao, Toldaiev, Oleksii, Vadruccio, Daniele, Varela, Joao, Vischia, Pietro, David Tinoco Mendes, Andre, Silva, Pedro, Musella, Pasquale, Pela, Joao
• Format: Article
• Language: eng
• Source: Repositórios Científicos de Acesso Aberto de Portugal (RCAAP)
• Download full: http://dx.doi.org/10.1140/epjc/s10052-017-4828-3; http://hdl.handle.net/10400.26/27283

This paper reports the measurement of $\mathrm{J}/{\psi }$ meson production in proton–proton ( $\mathrm {p}\mathrm {p}$ ) and proton–lead ( $\mathrm {p}\mathrm {Pb}$ ) collisions at a center-of-mass energy per nucleon pair of $5.02\,\text {TeV} $ by the CMS experiment at the LHC. The data samples used in the analysis correspond to integrated luminosities of 28 $\,\text {pb}^{-1}$ and 35 $\,\text {nb}^{-1}$ for $\mathrm {p}\mathrm {p}$ and $\mathrm {p}\mathrm {Pb}$ collisions, respectively. Prompt and nonprompt $\mathrm{J}/{\psi }$ mesons, the latter produced in the decay of ${\mathrm {B}}$ hadrons, are measured in their dimuon decay channels. Differential cross sections are measured in the transverse momentum range of $2<p_{\mathrm {T}} <30{\,\text {GeV}/{c}} $ , and center-of-mass rapidity ranges of $|y_\mathrm{{CM}} |<2.4$ ( $\mathrm {p}\mathrm {p}$ ) and $-2.87<y_\mathrm{{CM}}<1.93$ ( $\mathrm {p}\mathrm {Pb}$ ). The nuclear modification factor, $R_{\mathrm {p}\mathrm {Pb}}$ , is measured as a function of both $p_{\mathrm {T}}$ and $y_\mathrm{{CM}}$ . Small modifications to the $\mathrm{J}/{\psi }$ cross sections are observed in $\mathrm {p}\mathrm {Pb}$ relative to $\mathrm {p}\mathrm {p}$ collisions. The ratio of $\mathrm{J}/{\psi }$ production cross sections in $\mathrm {p}$ -going and Pb-going directions, $R_\mathrm{{FB}}$ , studied as functions of $p_{\mathrm {T}}$ and $y_\mathrm{{CM}}$ , shows a significant decrease for increasing transverse energy deposited at large pseudorapidities. These results, which cover a wide kinematic range, provide new insight on the role of cold nuclear matter effects on prompt and nonprompt $\mathrm{J}/{\psi }$ production.