Measurement of the production cross section ratio σ ([subscript χb2](1P))/σ ([subscript χb1](1P)) in pp collisions at √s = 8 TeV
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Khachatryan-2015-Measurement of the p.pdf
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Author(s)
Apyan, Aram
Barbieri, Richard Alexander
Busza, Wit
Cali, Ivan Amos
Di Matteo, Leonardo
Dutta, Valentina
Gomez-Ceballos, Guillelmo
Goncharov, Maxim
Gulhan, Doga Can
Klute, Markus
Date Issued
February 2015
Journal
Physics Letters B
Publisher
Elsevier
Citation
Khachatryan, V., et al. “Measurement of the Production Cross Section Ratio σ ([subscript χb2](1P))/σ ([subscript χb1](1P)) in pp collisions at √s = 8 TeV.” Physics Letters B 743 (April 2015): 383–402. © 2015 CERN for the benefit of the CMS Collaboration
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Final published version
Abstract
A measurement of the production cross section ratio σ([subscript χb2](1P))/σ([subscript χb1](1P)) is presented. The [subscript χb1](1P) and [subscript χb2](1P) bottomonium states, promptly produced in pp collisions at √s = 8 TeV, are detected by the CMS experiment at the CERN LHC through their radiative decays [subscript χb1,2](1P) → ϒ(1S) + γ. The emitted photons are measured through their conversion to e[superscript +]e[superscript −] pairs, whose reconstruction allows the two states to be resolved. The ϒ(1S) is measured through its decay to two muons. An event sample corresponding to an integrated luminosity of 20.7 fb[superscript −1] is used to measure the cross section ratio in a phase-space region defined by the photon pseudorapidity, |η[superscript γ]| < 1.0; the ϒ(1S) rapidity, |y[superscript ϒ]| < 1.5; and the ϒ(1S) transverse momentum, 7 < p[ϒ over T] < 40 GeV. The cross section ratio shows no significant dependence on the ϒ(1S) transverse momentum, with a measured average value of 0.85 ± 0.07 (stat + syst) ± 0.08 (BF), where the first uncertainty is the combination of the experimental statistical and systematic uncertainties and the second is from the uncertainty in the ratio of the [subscript χb] branching fractions.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Laboratory for Nuclear Science
Massachusetts Institute of Technology. School of Science
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DOI of Published Version
https://doi.org/10.1016/j.physletb.2015.02.048
