Universality and Lepton Flavor Violation in Upsilon Decays at CLEO

TL;DR

This paper reports on CLEOIII detector analyses of Upsilon decays, including a search for lepton flavor violation, tests of lepton universality, and constraints on CP-odd Higgs involvement, with significant improvements and the first observation of Upsilon(3S) to tau tau.

Contribution

It provides the first observation of Upsilon(3S) to tau tau and significantly improves measurements of lepton universality in Upsilon decays.

Findings

First observation of Upsilon(3S) to tau tau.

Improved constraints on lepton universality.

Set limits on CP-odd Higgs involvement.

Abstract

I present two analyses done with the CLEOIII detector at CESR. The first is a search for the Lepton Flavor Violating decay Upsilon to mu tau, with preliminary results, and the second constrains Lepton Universality in Upsilon to tau tau relative to Upsilon to mu mu. This second analysis, whose results are final, has dramatically improved uncertainties relative to other such measurements, and is also the first observation of the decay Upsilon(3S) to tau tau. A limit is also set on the involvement of a CP odd Higgs in the decay of the Upsilon(1S) to tau pairs.