Measurement of the ratio of branching fractions of the decays ${\text{Λ}}_b^o$ → ψ(2S)Λ and ${\text{Λ}}_b^o$ → J/ψΛ

Using pp collisions corresponding to 3 fb^–1 integrated luminosity, recorded by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV, the ratio of branching fractions B(${\text{Λ}}_b^o$ → ψ(2S)Λ)/B(${\text{Λ}}_b^o$ → J/ψΛ) = 0.513 ± 0.023(stat) ± 0.016(syst) ± 0.011 (B) is determined. The first uncertainty is statistical, the second is systematic and the third is due to the external branching fractions used.