Tau Neutrino Helicity from $h^{\pm}$ Energy Correlations

TL;DR

This paper measures the tau neutrino helicity by analyzing energy correlations in tau decays, providing a precise value consistent with the Standard Model prediction.

Contribution

It presents a novel measurement of tau neutrino helicity using energy correlations in tau decay events at CLEO.

Findings

Measured |xi| = 1.03 +/- 0.06 +/- 0.04

Results are consistent with the Standard Model

First precise energy correlation-based measurement of tau neutrino helicity

Abstract

We report a measurement of the magnitude of the tau neutrino helicity from tau-pair events taken with the CLEO detector at the CESR electron-positron storage ring. Events in which each tau undergoes the decay tau -> h nu, with h a charged pion or kaon, are analyzed for energy correlations between the daughter hadrons, yielding |xi| = 2*|h_nu| = 1.03 +/- 0.06 +/- 0.04, with the first error statistical and the second systematic.