Discrimination of models including doubly charged scalar bosons using tau decays

The doubly charged scalar boson ($H^{\pm \pm }$) is introduced in several models of the new physics beyond the standard model. The $H^{\pm \pm }$ has Yukawa interactions with two left-handed charged leptons or two right-handed charged leptons depending on the models. We study kinematical properties of $H^{\pm \pm }$ decay products through tau leptons in order to discriminate the chiral structures of the new Yukawa interaction. The chirality of tau leptons can be measured by the energy distributions of its decay products, and thus the chiral structure of the new Yukawa interaction can be traced in the invariant-mass distributions of the $H^{\pm \pm }$ decay products.