Abstract : 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.
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, Springer Verlag (Germany), 2012, 72, pp.2251. <10.1140/epjc/s10052-012-2251-3>. <in2p3-00737939>