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- Measurement of chi_c1 and chi_c2 production with sqrt(s) = 7 TeV pp collisions at ATLAS doi link

Auteur(s): Aad G., Albrand S., Brown J., Buat Q., Clement B., Collot J., Crépé-Renaudin S., Dechenaux B., Delemontex T., Delsart P.A., Gabaldon C., Genest M.H., Hostachy J.Y., Laisne E., Le B.T., Ledroit-Guillon F., Lleres A., Lucotte A., Malek F., Monini C., Stark J., Sun X., Trocmé B., Rahal G., Boumediene D., Busato Emmanuel, Calvet D., Calvet S., Donini J., Ughetto M.

(Article) Publié: Journal Of High Energy Physics, vol. 7 p.154 (2014)
Texte intégral en Openaccess : arXiv


Ref Arxiv: 1404.7035
DOI: 10.1007/JHEP07(2014)154
WoS: 000340391300001
Ref. & Cit.: NASA ADS
27 Citations
Résumé:

The prompt and non-prompt production cross-sections for the chi_c1 and chi_c2 charmonium states are measured in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector at the LHC using 4.5 fb^-1 of integrated luminosity. The chi_c states are reconstructed through the radiative decay chi_c -> J/psi gamma (with J/psi -> mu+mu-) where photons are reconstructed from gamma -> e+e- conversions. The production rate of the chi_c2 state relative to the chi_c1 state is measured for prompt and non-prompt chi_c as a function of J/psi transverse momentum. The prompt chi_c cross-sections are combined with existing measurements of prompt J/psi production to derive the fraction of prompt J/psi produced in feed-down from chi_c decays. The fractions of chi_c1 and chi_c2 produced in b-hadron decays are also measured. In addition to measurements of inclusive chi_c production, the branching fraction B(B+ -> chi_c1 K+) = (4.9 +/- 0.9 stat. +/- 0.6 syst.) * 10^-4 is measured with the same dataset and chi_c event selection.



Commentaires: See paper for full list of authors - 38 pages plus author list (62 pages total), 10 figures, 13 tables, submitted to JHEP, All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/BPHY-2013-05/