BARC/PUB/2014/0768

 
 

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

 
     
 
Author(s)

Khachatryan V.; Sirunyan A. M.; Tumasyan A.; Abdulsalam, A.; Dutta, D.; Kailas, S.; Kumar, V.; Mohanty, A. K.; Pant, L. M.; Shukla, P.; Topkar, A.; and others
(NPD)

Source

Journal of High Energy Physics, 2014. Vol. 9: Article no. 094

ABSTRACT

Production of prompt J/Ψ  meson pairs in proton-proton collisions at √s =7TeV 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 (pTJ/Ψ ) and rapidity (|yJ/Ψ |): |yJ/Ψ | < 1.2 for pJ/Ψ T > 6.5 GeV/c; 1.2 < |yJ/Ψ | < 1.43 for a pT threshold that scales linearly with |yJ/Ψ | from 6.5 to 4.5 GeV/c; and 1.43 < |yJ/Ψ | < 2.2 for pJ/Ψ T > 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%.

 
 
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