Measurements of Charged Current Lepton Universality and |Vus| Using Tau Lepton Decays to e−¯νeντ, μ−¯νμντ, π−ντ, and K−ντ

Abstract

Using 467 fb − 1 of e + e − annihilation data collected with the BABAR detector, we measure B ( τ − → μ − ¯ ν μ ν τ ) B ( τ − → e − ¯ ν e ν τ ) = ( 0.9796 ± 0.0016 ± 0.0036 ) , B ( τ − → π − ν τ ) B ( τ − → e − ¯ ν e ν τ ) = ( 0.5945 ± 0.0014 ± 0.0061 ) , and B ( τ − → K − ν τ ) B ( τ − → e − ¯ ν e ν τ ) = ( 0.03882 ± 0.00032 ± 0.00057 ) , where the uncertainties are statistical and systematic, respectively. From these precision τ measurements, we test the standard model assumption of μ − e and τ − μ charge current lepton universality and provide determinations of | V us | experimentally independent of the decay of a kaon.