Measurement of Υ production in pp collisions at √s=2.76TeV

Abstract

The production of Υ(1S), Υ(2S) and Υ(3S) mesons decaying into the dimuon final state is studied with the LHCb detector using a data sample corresponding to an integrated luminosity of 3.3pb−1 collected in proton–proton collisions at a centre-of-mass energy of s√=2.76 TeV. The differential production cross-sections times dimuon branching fractions are measured as functions of the Υ transverse momentum and rapidity, over the ranges pT<15 GeV/c and 2.0<y<4.5. The total cross-sections in this kinematic region, assuming unpolarised production, are measured to be

σ(pp→Υ(1S)X)×B(Υ(1S)→μ+μ−)=1.111±0.043±0.044nb,σ(pp→Υ(2S)X)×B(Υ(2S)→μ+μ−)=0.264±0.023±0.011nb,σ(pp→Υ(3S)X)×B(Υ(3S)→μ+μ−)=0.159±0.020±0.007nb, where the first uncertainty is statistical and the second systematic.