Measurement of ψ(2S) polarisation in pp collisions at s√ = 7 TeV

Abstract

The polarisation of prompt ψ(2S) mesons is measured by performing an angular analysis of ψ(2S)→μ+μ− decays using proton-proton collision data, corresponding to an integrated luminosity of 1.0 fb −1, collected by the LHCb detector at a centre-of-mass energy of 7 TeV. The polarisation is measured in bins of transverse momentum pT and rapidity y in the kinematic region 3.5<pT<15GeV/c and 2.0<y<4.5, and is compared to theoretical models. No significant polarisation is observed.