Search for Lepton Flavor Violation in the Decay tau -> electron gamma

TL;DR

This paper reports a search for lepton flavor violation in tau decays to electron gamma, using a large dataset, finding no evidence and setting a new upper limit on the decay's branching ratio.

Contribution

The study provides the most stringent upper limit to date on the branching ratio of tau -> electron gamma decay.

Findings

No evidence for lepton flavor violation was observed.

An upper limit of BR(tau -> electron gamma) < 1.1 x 10^-7 was established.

The results constrain new physics models predicting such decays.

Abstract

A search for the non-conservation of lepton flavor in the decay tau -> electron gamma has been performed with 2.07 x 10^8 e+e- -> tau+ tau- events collected by the BABAR detector at the PEP-II storage ring at a center-of-mass energy near 10.58 GeV. We find no evidence for a signal and set an upper limit on the branching ratio of BR(tau -> electron gamma) < 1.1 x 10^-7 at 90% confidence level.