Measurement of b-hadron masses

Measurements of b-hadron masses are performed with the exclusive decay modes B+→J/ψK+, B0→J/ψK⁎0, B0→J/ψKS0, Bs0→J/ψϕ and Λb0→J/ψΛ using an integrated luminosity of 35pb−1 collected in pp collisions at a centre-of-mass energy of 7 TeV by the LHCb experiment. The momentum scale is calibrated with J/ψ→μ+μ− decays and verified to be known to a relative precision of 2 ×10−4 using other two-body decays. The results are more precise than previous measurements, particularly in the case of the Bs0 and Λb0 masses.