Measurement of the production cross section ratio $\sigma(\chi_{b2}(1\mathrm{P}))/ \sigma(\chi_{b1}(1\mathrm{P}))$ in pp collisions at $\sqrt{s}$ = 8 TeV

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=8TeV, 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−1is used to measure the cross section ratio in a phase-space region defined by the photon pseudorapidity, |ηγ