Measurement of the relative prompt production rate of chi(c2) and chi(c1) in pp collisions at sqrt(s) = 7 TeV

S. Chatrchyan , M. Besançon (1) , S. Choudhury (1) , M. Dejardin (1) , D. Denegri (1) , B. Fabbro (1) , J.L. Faure (1) , F. Ferri (1) , S. Ganjour (1) , A. Givernaud (1) , P. Gras (1) , G. Hamel de Monchenault (1) , P. Jarry (1) , E. Locci (1) , J. Malcles (1) , L. Millischer (1) , A. Nayak (1) , J. Rander (1) , A. Rosowsky (1) , I. Shreyber (1) , M. Titov (1) , S. Baffioni (2) , F. Beaudette (2) , L. Benhabib (2) , L. Bianchini (2) , M. Bluj (2) , C. Broutin (2) , Pierre Busson (2) , C. Charlot (2) , N. Daci (2) , T. Dahms (2) , L. Dobrzynski (2) , R. Granier de Cassagnac (2) , M. Haguenauer (2) , P. Mine (2) , C. Mironov (2) , I.N. Naranjo (2) , M. Nguyen (2) , C. Ochando (2) , P. Paganini (2) , D. Sabes (2) , R. Salerno (2) , Y. Sirois (2) , C. Veelken (2) , A. Zabi (2) , J.-L. Agram (3) , J. Andrea (3) , D. Bloch (3) , D. Bodin (3) , J.-M. Brom (3) , M. Cardaci (3) , E.C. Chabert (3) , C. Collard (3) , E. Conte (3) , F. Drouhin (3) , C. Ferro (3) , J.-C. Fontaine (3) , D. Gele (3) , U. Goerlach (3) , P. Juillot (3) , A.-C. Le Bihan (3) , P. van Hove (3) , F. Fassi (4) , D. Mercier (4) , S. Beauceron (5) , N. Beaupere (5) , O. Bondu (5) , G. Boudoul (5) , J. Chasserat (5) , R. Chierici (5) , D. Contardo (5) , P. Depasse (5) , H. El Mamouni (5) , J. Fay (5) , S. Gascon (5) , M. Gouzevitch (5) , B. Ille (5) , T. Kurca (5) , M. Lethuillier (5) , L. Mirabito (5) , S. Perries (5) , V. Sordini (5) , Y. Tschudi (5) , P. Verdier (5) , S. Viret (5)

1 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
2 LLR - Laboratoire Leprince-Ringuet
3 DRS-IPHC - Département Recherches Subatomiques
4 CC-IN2P3 - Centre de Calcul de l'IN2P3
5 IPNL - Institut de Physique Nucléaire de Lyon

A measurement is presented of the relative prompt production rate of chi(c2) and chi(c1) with 4.6 inverse femtobarns of data collected by the CMS experiment at the LHC in pp collisions at sqrt(s) = 7 TeV. The two states are measured via their radiative decays chi(c) to J/psi + gamma, with the photon converting into a dielectron pair for J/psi rapidity abs(y(J/psi)) < 1.0 and photon transverse momentum pt(gamma) > 0.5 GeV. The measurement is given for six intervals of pt(J/psi) between 7 and 25 GeV. The results are compared to theoretical predictions.

Domaines: Physique des Hautes Energies - Expérience [hep-ex]

S. Chatrchyan, M. Besançon, S. Choudhury, M. Dejardin, D. Denegri, et al.. Measurement of the relative prompt production rate of chi(c2) and chi(c1) in pp collisions at sqrt(s) = 7 TeV. European Physical Journal C: Particles and Fields, 2012, 72, pp.2251. ⟨10.1140/epjc/s10052-012-2251-3⟩. ⟨in2p3-00737939⟩