K-S(0) production in tau decays

From a sample of about 160k Z --> tau(+)tau(-) candidates collected with the ALEPH detector at LEP between 1991 and 1995, tau lepton decays involving K-S(0) --> pi(+)pi(-) are studied. The (KSKL0)-K-0 associated production in 7 decays is also investigated. The branching ratios are measured for the inclusive decay B(tau(-) --> K(S)(0)X(-)nu(tau)) = (9.70 +/- 0.58 +/- 0.62) x 10(-3), where X- can be anything, and for the exclusive decays B(tau(-) --> (K) over bar(0) pi(-)nu(tau) = (8.55+/-1.17+/-0.66) x 10(-3), B(tau(-) --> (K) over bar(0) pi(-)pi(0)nu(tau)) = (2.94 +/- 0.73 +/- 0.37) x 10(-3), B(tau(-) --> (K) over bar(0)K(-)nu(tau)) = (1.58 +/- 0.42 +/- 0.17) x 10(-3), B(tau(-) --> (K) over bar(0)K(-)pi(0)nu(tau)) = (1.52 +/- 0.76 +/- 0.21) x 10(-3). The decay tau(-) --> K(S)(0)K(L)(0)pi(-)nu(tau) is studied for the first time, giving a branching ratio B(tau(-) --> K(S)(0)K(L)(0)pi(-)nu(tau)) = (1.01 +/- 0.23 +/- 0.13) x 10(-3). The channels tau(-) --> K(S)(0)K(S)(0)pi(-)nu(tau), tau(-) --> K(S)(0)K(S)(0)pi(-)pi(0)nu(tau), tau(-) --> K(S)(0)K(L)(0)pi(-)pi(0)nu(tau), tau- --> (K) over bar(0) pi(-)pi(0)nu(tau), tau(-) --> K(0)K(-)pi(0)pi(0)nu(tau) and tau- --> K(0)h(+)h(-)h(-)v(tau) are also investigated. In addition, mass spectra in the K(S)(0)h(-) and K(S)(0)h(-)pi(0) final states are analysed to provide information on the intermediate states produced in the decays.