Measurements of the absolute branching fractions for Ds+ →ηe+νe and Ds+ →η′e+νe

Abstract

By analyzing 482 pb-1 of e+e- collision data collected at s=4.009 GeV with the BESIII detector at the BEPCII collider, we measure the absolute branching fractions for the semileptonic decays Ds+→ηe+νe and Ds+→η′e+νe to be B(Ds+→ηe+νe)=(2.30±0.31±0.08)% and B(Ds+→η′e+νe)=(0.93±0.30±0.05)%, respectively, and their ratio B(Ds+→η′e+νe)B(Ds+→ηe+νe)=0.40±0.14±0.02, where the first uncertainties are statistical and the second ones are systematic. The results are in good agreement with previous measurements within uncertainties; they can be used to determine the η-η′ mixing angle and improve upon the Ds+ semileptonic branching ratio precision.