# Measurement of prompt J/ψ pair production in pp collisions at s√ = 7 Tev

CMS Collaboration; Khachatryan, V; Sirunyan, A M; Tumasyan, A; et al; Amsler, C; Canelli, F; Chiochia, V; De Cosa, A; Hinzmann, A; Hreus, T; Ronga, F J; Kilminster, B; Mejias, B; Ngadiuba, J; Robmann, P; Snoek, H; Taroni, S; Verzetti, M; Yang, Y (2014). Measurement of prompt J/ψ pair production in pp collisions at s√ = 7 Tev. Journal of High Energy Physics, 2014(94):online.

## Abstract

Production of prompt J/ψ meson pairs in proton-proton collisions at s√ = 7 TeV is measured with the CMS experiment at the LHC in a data sample corresponding to an integrated luminosity of about 4.7 fb−1. The two J/ψ mesons are fully reconstructed via their decays into μ+ μ− pairs. This observation provides for the first time access to the high-transverse-momentum region of J/ψ pair production where model predictions are not yet established. The total and differential cross sections are measured in a phase space defined by the individual J/ψ transverse momentum (p_{T}^{J/}^{ψ}) and rapidity (|y^{J/}^{ψ} |): |y^{J/}^{ψ} | < 1.2 for p_{T}^{J/}^{ψ} > 6.5 GeV/c, 1.2 < |y^{J/}^{ψ} | < 1.43 for a pT threshold that scales linearly with |y^{J/}^{ψ} | from 6.5 to 4.5 GeV/c, and 1.43 < |y^{J/}^{ψ} | < 2.2 for p_{T}^{J/}^{ψ} > 4.5 GeV/c. The total cross section, assuming unpolarized prompt J/ψ pair production is 1.49 ± 0.07 (stat) ±0.13 (syst) nb. Different assumptions about the J/ψ polarization imply modifications to the cross section ranging from −31% to +27%.

## Abstract

Production of prompt J/ψ meson pairs in proton-proton collisions at s√ = 7 TeV is measured with the CMS experiment at the LHC in a data sample corresponding to an integrated luminosity of about 4.7 fb−1. The two J/ψ mesons are fully reconstructed via their decays into μ+ μ− pairs. This observation provides for the first time access to the high-transverse-momentum region of J/ψ pair production where model predictions are not yet established. The total and differential cross sections are measured in a phase space defined by the individual J/ψ transverse momentum (p_{T}^{J/}^{ψ}) and rapidity (|y^{J/}^{ψ} |): |y^{J/}^{ψ} | < 1.2 for p_{T}^{J/}^{ψ} > 6.5 GeV/c, 1.2 < |y^{J/}^{ψ} | < 1.43 for a pT threshold that scales linearly with |y^{J/}^{ψ} | from 6.5 to 4.5 GeV/c, and 1.43 < |y^{J/}^{ψ} | < 2.2 for p_{T}^{J/}^{ψ} > 4.5 GeV/c. The total cross section, assuming unpolarized prompt J/ψ pair production is 1.49 ± 0.07 (stat) ±0.13 (syst) nb. Different assumptions about the J/ψ polarization imply modifications to the cross section ranging from −31% to +27%.

## Citations

10 citations in Web of Science®
10 citations in Scopus®

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Item Type: Journal Article, refereed, original work 07 Faculty of Science > Physics Institute 530 Physics English 2014 12 Dec 2014 09:06 05 Apr 2016 18:37 Springer 1029-8479 Publisher DOI. An embargo period may apply. https://doi.org/10.1007/JHEP09(2014)094 http://arxiv.org/abs/1406.0484

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