Compact Muon Solenoid
LHC, CERN
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| CMS-PAS-BPH-13-005 | ||
| Measurement of the $\chi_{\mathrm{b}2} / \chi_{\mathrm{b}1}$ production cross section ratio in pp collisions at $\sqrt{s}$ = 8 TeV | ||
| CMS Collaboration | ||
| 2013 | ||
| Abstract: The ratio of cross sections of $\chi_{\mathrm{b}2}(1\mathrm{P})$ and $\chi_{\mathrm{b}1}(1\mathrm{P})$ bottomonium states promptly produced in pp collisions at $\sqrt{s}=$ 8 TeV is measured by detecting their radiative decays $\chi_{\mathrm{b}1,2}(1\mathrm{P}) \rightarrow \Upsilon(1\mathrm{S}) + \gamma$ with the CMS experiment. The emitted photons are detected through their conversion to $e^+e^-$ pairs, with the electron trajectories accurately reconstructed in the silicon tracker, so that the two states can be resolved with a good mass resolution. The measurement is based on an event sample corresponding to an integrated luminosity of 20.7 fb$^{-1}$ and is performed in a phase space region defined by selection cuts on the photon pseudorapidity and on the $\Upsilon$ transverse momentum and rapidity: $| \eta^\gamma | <$ 1.0, 7 $< p_{\rm T}^\Upsilon <$ 40 GeV, and $|y^\Upsilon | < 1.5$. The measured cross-section ratio is around 0.9, with no significant dependence on $p_{\rm T}^\Y$. | ||
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Links:
CDS record (PDF) ;
inSPIRE record ;
Public twiki page ;
CADI line (restricted) ;
These preliminary results are superseded in this paper, PLB 743 (2015) 383. The superseded preliminary plots can be found here. |
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Compact Muon Solenoid LHC, CERN |
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