Measurement of the ratio of branching fractions of the decays $Lambda^0_b!topsi(2S) Lambda$ and $Lambda^0_b!to J/psi Lambda$

Using $pp$ collisions corresponding to 3$,text{fb}^{-1}$ integrated luminosity, recorded by the LHCb experiment at centre-of-mass energies of 7 and 8$,text{TeV}$, the ratio of branching fractions begin{align*} mathcal{B}(Lambda^0_b!topsi(2S) Lambda )/mathcal{B}(Lambda^0_b!to J/psi Lambda)= 0.513 pm 0.023, (text{stat}) pm 0.016 , (text{syst}) pm 0.011, (mathcal{B}) end{align*} is determined. The first uncertainty is statistical, the second is systematic and the third is due to the external branching fractions used.