Compact Muon Solenoid
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| CMS-BPH-13-005 ; CERN-PH-EP-2014-217 | ||
| Measurement of the production cross section ratio $\sigma(\chi_{b2}(1\mathrm{P}))/ \sigma(\chi_{b1}(1\mathrm{P}))$ in pp collisions at $\sqrt{s}$ = 8 TeV | ||
| CMS Collaboration | ||
| 19 September 2014 | ||
| Phys. Lett. B 743 (2015) 383 | ||
| Abstract: A measurement of the production cross section ratio $\sigma(\chi_{b2}(1\mathrm{P}))/ \sigma(\chi_{b1}(1\mathrm{P}))$ is presented. The $\chi_{b1}(1\mathrm{P})$ and $\chi_{b2}(1\mathrm{P})$ bottomonium states, promptly produced in pp collisions at $\sqrt{s}$= 8 TeV, are detected by the CMS experiment at the CERN LHC through their radiative decays $\chi_{b1,2}(1\mathrm{P}) \rightarrow \Upsilon(1\mathrm{S}) + \gamma$. The emitted photons are measured through their conversion to e$^+$e$^-$ pairs, whose reconstruction allows the two states to be resolved. The $\Upsilon(1\mathrm{S})$ is measured through its decay to two muons. An event sample corresponding to an integrated luminosity of 20.7 fb$^{-1}$ is used to measure the cross section ratio in a phase-space region defined by the photon pseudorapidity, |$\eta^\gamma$| < 1.0; the $\Upsilon(1\mathrm{S})$ rapidity, |$y^\Upsilon$| < 1.5; and the $\Upsilon(1\mathrm{S})$ transverse momentum, 7 < $p_{\mathrm{T}}^\Upsilon$ < 40 GeV. The cross section ratio shows no significant dependence on the $\Upsilon(1\mathrm{S})$ transverse momentum, with a measured average value of 0.85 $\pm$ 0.07 (stat+syst) $\pm$ 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 $\chi_{b}$ branching fractions. | ||
| Links: e-print arXiv:1409.5761 [hep-ex] (PDF) ; CDS record ; inSPIRE record ; Public twiki page ; CADI line (restricted) ; | ||
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Compact Muon Solenoid LHC, CERN |
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