# Measurement of the cross-section ratio $\sigma(\chi_{c2})/\sigma(\chi_{c1})$ for prompt $\chi_c$ production at $\sqrt{s}=7$ TeV

Abstract : The prompt production of the charmonium $\chi_{c1}$ and $\chi_{c2}$ mesons has been studied in proton-proton collisions at the Large Hadron Collider at a centre-of-mass energy of $\sqrt{s}=7$ TeV. The $\chi_c$ mesons are identified through their decays $\chi_c\to J/\psi\,\gamma$ with $J/\psi \to \mu^+ \mu^-$ using 36 $\mathrm{pb^{-1}}$ of data collected by the LHCb detector in 2010. The ratio of the prompt production cross-sections for the two $\chi_c$ spin states, $\sigma(\chi_{c2})/\sigma(\chi_{c1})$, has been determined as a function of the $J/\psi$ transverse momentum, $p_{\mathrm{T}}^{J/\psi}$, in the range from 2 to 15 GeV/$c$. The results are in agreement with the next-to-leading order non-relativistic QCD model at high $p_{\mathrm{T}}^{J/\psi}$ and lie consistently above the pure leading-order colour singlet prediction.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-00668373
Contributor : Claudine Bombar Connect in order to contact the contributor
Submitted on : Thursday, February 9, 2012 - 4:46:14 PM
Last modification on : Saturday, January 15, 2022 - 3:08:11 PM

### Citation

R. Aaij, C. Abellan Beteta, B. Adeva, M. Adinolfi, C. Adrover, et al.. Measurement of the cross-section ratio $\sigma(\chi_{c2})/\sigma(\chi_{c1})$ for prompt $\chi_c$ production at $\sqrt{s}=7$ TeV. Physics Letters B, Elsevier, 2012, 714, pp.215-223. ⟨10.1016/j.physletb.2012.06.077⟩. ⟨in2p3-00668373⟩

### Metrics

Les métriques sont temporairement indisponibles