Measurement of the B± production asymmetry and the C P asymmetry in B±→J /ψ K± decays

Abstract

The B± meson production asymmetry in p p collisions is measured using B+→D¯ 0 π+ decays. The data were recorded by the LHCb experiment during Run 1 of the LHC at center-of-mass energies of √{s }=7 and 8 TeV. The production asymmetries, integrated over transverse momenta in the range 2 <pT<30 GeV /c , and rapidities in the range 2.1 <y <4.5 are measured to be Aprod(B+,√{s }=7 TeV )=(-0.41 ±0.49 ±0.10 )×10-2 , Aprod(B+,√{s }=8 TeV )=(-0.53 ±0.31 ±0.10 )×10-2 , where the first uncertainties are statistical and the second are systematic. These production asymmetries are used to correct the raw asymmetries of B+→J /ψ K+ decays, thus allowing a measurement of the C P asymmetry, AC P(B+→J /ψ K+) =(0.09 ±0.27 ±0.07 ) ×10-2 .