Measurement of the $η_c (1S)$ production cross-section in proton-proton collisions via the decay $η_c (1S) \rightarrow p \barp$статья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 22 октября 2015 г.
Аннотация:
The production of the ηc(1S) state in proton-proton collisions is probed via its decay to the p p¯¯¯ final state with the LHCb detector, in the rapidity range 2.0<y<4.5 and in the meson transverse-momentum range pT>6.5GeV/c. The cross-section for prompt production of ηc(1S) mesons relative to the prompt J/ψ cross-section is measured, for the first time, to be σηc(1S)/σJ/ψ=1.74±0.29±0.28±0.18B at a centre-of-mass energy s√=7TeV using data corresponding to an integrated luminosity of 0.7 fb−1, and σηc(1S)/σJ/ψ=1.60±0.29±0.25±0.17B at s√=8TeV using 2.0 fb−1. The uncertainties quoted are, in order, statistical, systematic, and that on the ratio of branching fractions of the ηc(1S) and J/ψ decays to the p p¯¯¯ final state. In addition, the inclusive branching fraction of b -hadron decays into ηc(1S) mesons is measured, for the first time, to be B(b→ηcX)=(4.88±0.64±0.29±0.67B)×10−3, where the third uncertainty includes also the uncertainty on the J/ψ inclusive branching fraction from b -hadron decays. The difference between the J/ψ and ηc(1S) meson masses is determined to be 114.7±1.5±0.1MeV/c2.