Measurement of $\cal{B}(B^0_s \to \psi(2S) \phi) / \cal{B}(B^0_s \to J/\psi \phi$)

We describe a measurement of the ratio of the branching fractions for $B^0_s\rightarrow\psi(2S)\phi$ and $B^0_s\rightarrow J/\psi\phi$ with approximately 36 pb$^{-1}$ of data collected at $\sqrt{s}$ = 7 TeV during the 2010 run at LHCb. The result is 0.68$\pm$0.10(stat)$\pm$0.09(syst)$\pm$ 0.07($\cal B$), which is compatible with previous measurements from experiments at the Tevatron.