The effect of the masses of the τ decay products on the transverse spin correlation in τ+τ− production at the Z pole

The effect of the masses of the τ decay products on the measurement of the transverse spin correlations in τ+τ− production is discussed. The cross section as a function of the polar, acollinearity and aplanarity angles is calculated for the case of non-vanishing masses using a Monte Carlo method. As an example the method is applied to the τ decay modes: π, ϱ and μe, but, in fact, it can be applied to any τ decay mode.