A measurement of the production cross section ratio σ(χb2(1P))/σ(χb1(1P)) is presented. The χb1(1P) and χb2(1P) bottomonium states, promptly produced in pp collisions at √s = 8 TeV, are detected by the CMS experiment at the CERN LHC through their radiative decays χb1,2(1P) → ϒ(1S) + γ. The emitted photons are measured through their conversion to e+e− pairs, whose reconstruction allows the two states to be resolved. The ϒ(1S) is measured through its decay to two muons. An event sample corresponding to an integrated luminosity of 20.7fb−1 is used to measure the cross section ratio in a phase-space region defined by the photon pseudorapidity, |ηγ| < 1.0; the ϒ(1S) rapidity, |yϒ| < 1.5; and the ϒ(1S) transverse momentum, 7 < pϒT < 40 GeV. The cross section ratio shows no significant dependence on the ϒ(1S) transverse momentum, with a measured average value of 0.85 ±0.07 (stat+syst) ±0.08 (BF), where the first uncertainty is the combination of the experimental statistical and systematic uncertainties and the second is from the uncertainty in the ratio of the χb branching fractions.
- Quarkonium production
- P-wave states