Observations of B0 s → ψ(2S)η and B0 (s) → ψ(2S)π+π− decays

Abstract

First observations of the B0s→ψ(2S)η,B0→ψ(2S)π+π− and B0s→ψ(2S)π+π− decays are made using a dataset corresponding to an integrated luminosity of 1.0 fb−1 collected by the LHCb experiment in proton–proton collisions at a centre-of-mass energy of √s=7 TeV. The ratios of the branching fractionsof each of the ψ(2S) modes with respect to the corresponding J/ψ decays are B(B0s→ψ(2S)η)B(B0s→J/ψη)=0.83±0.14(stat)±0.12(syst)±0.02(B),B(B0→ψ(2S)π+π−)B(B0→J/ψπ+π−)=0.56±0.07(stat)±0.05(syst)±0.01(B),B(B0s→ψ(2S)π+π−)B(B0s→J/ψπ+π−)=0.34±0.04(stat)±0.03(syst)±0.01(B), where the third uncertainty corresponds to the uncertainties of the dilepton branching fractions of the J/ψandψ(2S) meson decays.