TauDecay: a library to simulate polarized tau decays via FeynRules and MadGraph5

Abstract

TauDecay is a library of helicity amplitudes to simulate polarized tau decays, constructed in the FeynRules and MadGraph5 framework. Together with the leptonic mode, the decay library includes the main hadronic modes, τ\to ν_τ+π, 2π, and 3π, which are introduced as effective vertices by using FeynRules. The model file allows us to simulate tau decays when the on-shell tau production is kinematically forbidden. We also demonstrate that all possible correlations among the decay products of pair-produced taus through a Z boson and a scalar/pseudoscalar Higgs boson are produced automatically. The program has been tested carefully by making use of the standard tau decay library Tauola.

10 pages, 12 figures, 3 tables; v2: typo in Eq.(20b) corrected, references added, version accepted by EPJC. 'Note added' also included for the brief TauDecay instruction in MadGraph5_aMC@NLO