A search for top decay into tau, neutrino and quark in top-antitop production

TL;DR

This paper searches for top-antitop events involving tau leptons, neutrinos, and quarks, using data from proton-antiproton collisions, and sets an upper limit on the decay rate ratio involving tau leptons.

Contribution

It provides the first experimental upper limit on the ratio of top decays to tau neutrinos and quarks in top-antitop production at Tevatron energies.

Findings

Observed two events consistent with background expectations.

Set a 95% confidence level upper limit of 5.2 on the decay rate ratio.

Data sample corresponds to 194 pb^-1 collected with CDF II.

Abstract

We present a search for top-antitop events with a tau lepton in the final state. The data sample corresponds to an integrated luminosity of 194/pb collected with the CDF II detector from proton-antiproton collisions at a center of mass energy of 1.96 TeV. We observe two events with an expected signal of 1.0+/-0.2 events and a background of 1.3+/-0.3 events. We determine a 95% confidence level upper limit on r_tau, the ratio of the measured rate of top->tau nu quark to the expectation, of 5.2.