Analysis of τ 1-prong exclusive branching ratios using neural networks

A FFNN has been used to identify six different 1-prong τ decays among the τ+τ− events collected by the DELPHI experiment at LEP. The method operates with better efficiency-purity than the classical methods for the previously studied channels and allows the possibility of analysing a new one. It has been applied to 1993 and 1994 data to obtain the branching fractions of these channels. A first estimation of the systematic errors has been performed.