Analysis of τ-mesons

Abstract

We describe in this paper measurements made on the decay products of 11 τ-mesons observed in large nuclear emulsion block detectors. Out of the 33 charged decay products; 27 have been arrested in the block, and were identified as π-mesons. The charge of the τ-meson was found to be positive in 6 cases. In one case the charge of the τ-meson is possibly negative and in 4 cases it could not be determined. Omitting one τ-meson in which a high energy γ-ray is emitted and which has been reported earlier the weighted mean Q-value of the remaining 10 τ-mesons is: Q_τ = 76.3 ± 0.3MeV which gives the mass of the τ -meson as: m_τ =968.7 ± 0.6m_e This value is slightly higher than the mean value 965.5 ± 0.7m _e compiled by Amaldiet al. from measurements of various laboratories.