One-prong tau decays with kaons

Abstract

One-prong tau decays into final states involving kaons are studied with about 161k tau+tau- events collected by the ALEPH detector from 1991 to 1995. Charged kaons are identified by dE/dx measurement, while K0L's are detected through their interaction in calorimeters. Branching ratios are measured for the inclusive mode, B(tau- -> K-Xnu_tau)=(1.52 +- 0.04 +- 0.04)%, where X can be any system of neutral particles, and for the exclusive modes B(tau- to K- nu_tau) = (6.96 =- 0.25 +- 0.14)x 10-3, B(tau- to K- pi0 nu_tau) = (4.44 +- 0.26 +- 0.24)x 10-3, B(tau-to K- pi0 pi0 nu_tau)= (0.56 +- 0.20 +- 0.15) x 10-3, B(tau- to K- pi0 pi0 pi0 nu_tau = (0.37 +- 0.21 +- 0.11) x 10-3, B(tau- to K-K0 nu_tau) = (1.62 +- 0.21 +- 0.11) x 10-3, B(tau- to K-K0 pi0 nu_tau) = (1.43 +- 0.25 +- 0.21)x 10-3, B(tau- to \overline{K0} pi- nu_tau) = (9.28 +- 0.45 +- 0.34)x 10-3, B(tau- to \overline{K0} pi-pi0 nu_tau) = (3.47 +- 0.53 +- 0.37) x 10-3. Upper limits for B(tau- to \overline{K0} pi- pi0 pi0 nu_tau) and B(tau- to K- K0 pi0 pi0 nu_tau are also obtained. Mass spectra in the final states are addressed in order to study the relevant dynamics.