Measurements of the Ratios ${\cal B}(D_s^+\to η\ell^+ν)/{\cal B}(D_s^+\to ϕ\ell^+ν)$ and ${\cal B}(D_s^+\to η'\ell^+ν)/{\cal B}(D_s^+\to ϕ\ell^+ν)$

Abstract

Using the CLEO~II detector we measure ${\cal B}(D_s^+\to ηe^+ν)/{\cal B}(D_s^+\to ϕe^+ν) =1.24\pm0.12\pm0.15$, ${\cal B}(D_s^+\to η' e^+ν)/{\cal B}(D_s^+\to ϕe^+ν) =0.43\pm0.11\pm0.07$ and ${\cal B}(D_s^+\to η' e^+ν)/{\cal B}(D_s^+\to ηe^+ν) =0.35\pm0.09\pm0.07$. We find the vector to pseudoscalar ratio, ${\cal B}(D_s^+\to ϕe^+ν)/{\cal B}(D_s^+\to (η+η') e^+ν) =0.60\pm0.06\pm0.06$, which is similar to the ratio found in non strange $D$ decays.