Measurements of charged current lepton universality and [formula omitted] using tau one-prong decays with the BaBar detector

Abstract

We present measurements of B ( τ − → μ − ν ¯ μ ν τ ) / B ( τ − → e − ν ¯ e ν τ ) , B ( τ − → π − ν τ ) / B ( τ − → e − ν ¯ e ν τ ) , and B ( τ − → K − ν τ ) / B ( τ − → e − ν ¯ e ν τ ) using e + e − annihilation data collected with the BaBar detector. 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 the | V u s | CKM matrix element.