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, \tau \to \nu_{\tau}+\pi, 2\pi, and 3\pi, 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.

Comments: 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