Measurement of the branching fractions of the radiative leptonicτdecaysτ→eγνν¯andτ→μγνν¯atBABAR

Abstract

We perform a measurement of the τ→lγνν¯ (l=e,μ) branching fractions for a minimum photon energy of 10 MeV in the τ rest frame, using 431 fb−1 of e+e− collisions collected at the center-of-mass energy of the ϒ(4S) resonance with the BABAR detector at the PEP-II storage rings. We find B(τ→μγνν¯)=(3.69±0.03±0.10)×10−3 and B(τ→eγνν¯)=(1.847±0.015±0.052)×10−2, where the first quoted error is statistical and the second is systematic. These results are substantially more precise than previous measurements.Received 10 February 2015DOI:https://doi.org/10.1103/PhysRevD.91.051103© 2015 American Physical Society