In a wire spark-chamber experiment the squared matrix element |M|2 has been measured for the processes τ± (K± → π±π±π∓). Our previous results showed no significant difference between τ+ and τ-. The final results, based on ∼1.5 million τ± decays, are expressed in the form |M|2 ∝ 1 + aY + bX2 + cY2 + ..., where X and Y are the Dalitz variables. The data are adequately fitted by a quadratic expansion where a = 0.2752 ± 0.0033; b = -0.038 ± 0.009; c = 0.025 ± 0.010. Results are also given for τ+ and τ- separately. Finally we have determined the difference between the Q values of τ+ and τ- to be: Q+ - Q- = -60±55 keV.
ASJC Scopus subject areas
- Nuclear and High Energy Physics