τ Decays to pions

Decays into Three Pions

We propose a phenomenological three component model describing the decay amplitude of the process D s → 3π. The first component is a constant background, the second one is a Breit-Wigner amplitude associated to a quasi two-body f0(980)π + state and the third one another Breit-Wigner amplitude corresponding to a possible quasi two-body ρ(770)π state. We show that it is possible to reproduce the ...

τ → ω3πν Decays

Theoretical study of anomalous decay mode τ → ωπππν is presented. Theoretical value of the branching ratio of τ − → ωπ − π 0 π 0 ν agrees well with data. The branching ratio of τ − → ωπ + π − π − ν τ is predicted. It is found that the vertices of a 1 ρπ and ωρπ play dominant role in these two decay modes. CVC is satisfied and there is no adjustable parameter.

Rare τ decays

The availability of large samples of τ leptons allows for searches of very rare (Standard Model forbidden) τ decay modes, which provide a sensitive probe for physics beyond the Standard Model (BSM). In recent years, very large samples of τ leptons have been made available by the high luminosity running of the two asymmetric B-factories PEP − II and KEK B, which, in light of the comparable size ...

Vus From Hadronic τ Decays

We study extractions of |Vus| based on finite energy sum rule (FESR) analyses of hadronic τ decay data. We show (i) that the “(0,0) spectral weight” implementation (proposed previously in the literature as a favorable version of this analysis) suffers from significant convergence problems, but (ii) that alternate implementations exist which bring these problems under control. Results based on p...

First Observation of τ→3πηντ and τ→ f1πντ Decays