Search for Lepton-Flavor Violation in the Decay tau -> lhh

TL;DR

This study searches for lepton-flavor-violating tau decays into a lepton and two hadrons using BABAR data, setting upper limits on branching fractions due to no observed excess over background.

Contribution

First comprehensive search for tau lepton flavor violation in decay modes with a lepton and two hadrons using large BABAR dataset.

Findings

No significant signal observed in any decay mode.

Upper limits on branching fractions range from 0.7 to 4.8 x 10^{-7}.

Results constrain new physics models predicting lepton-flavor violation.

Abstract

A search for the lepton-flavor-violating decay of the tau into one charged lepton and two charged hadrons has been performed using $221.4 \mathrm{fb}^{-1}$ of data collected at an $e^+e^-$ center-of-mass energy around 10.58 GeV with the BABAR detector at the PEP-II storage ring. In all 14 decay modes considered, the numbers of events found in data are compatible with the background expectations. Upper limits on the branching fractions are set in the range $(0.7-4.8)\times 10^{-7}$ at 90% confidence level. All results are preliminary.