# Measurement of the ratio of branching fractions of the decays Λ b 0  →  ψ (2 S )Λ and Λ b 0  →  J / ψ Λ

25 March 2019

Abstract: 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 Λ b 0 → ψ 2 S Λ / ℬ Λ b 0 → J / ψ Λ = 0.513 ± 0.023 stat ± 0.016 syst ± 0.011 ℬ $\mathrm{\mathcal{B}}\left({\Lambda}_b^0\to \psi (2S)\Lambda \right)/\mathrm{\mathcal{B}}\left({\Lambda}_b^0\to J/\psi \Lambda \right)=0.513\pm 0.023\left(\mathrm{stat}\right)\pm 0.016\left(\mathrm{syst}\right)\pm 0.011\left(\mathrm{\mathcal{B}}\right)$ is determined. The first uncertainty is statistical, the second is systematic and the third is due to the external branching fractions used.

Published in: JHEP 1903 (2019) 126