Study of the semileptonic τ -→π- π0ντ and τ- → π- π0?+?-ντ (? = e, μ) decays.

30th Annual Meeting of the Division of Particles and Fields (DPyC) of the Mexican Physical Society

Santiago, J. L. Gutiérrez^1

Departamento de Fisica, Cinvestav-IPN, Apdo. Postal 14-740, Ciudad de México

07000, Mexico^1

关键词: Anomalous magnetic moments;    Decay mode;    In-process;    Lepton number violations;    Model vectors;    System Dynamics;    Vacuum polarization;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/761/1/012059/pdf
DOI  :  10.1088/1742-6596/761/1/012059

来源: IOP

【 摘 要 】

We analyze the decay modes τ-→π-π0μτand τ-π-π0+-μτ, =e, μ. The first one is studied in order to show that the three resonances p(770), p(1450) and p(1700) are necessary to fix the model vector dominance parameters on the two pion system dynamics. We have obtained BR(τ-→π-π0vτ) = (25.40±0.22)% which is in good agreement with the world average reported in the PDG. The second decay, which is the target of our study, is important because it can participate as a background in processes of lepton flavour and lepton number violation and thus its accurate description is essential in searches for such processes. It is also important to test the model dependence of the most important (ππ) contribution to the hadron vacuum polarization (HVP) entering the muon anomalous magnetic moment, if evaluated using hadronic tau decay data. In these preliminary results, we have only taken into account the total Inner Bremmsstrahlung (IB) contribution to the τ-→π-π0+-μτdecays obtaining BR(τ-→ π-π0e+e-μτ) = (8.09 ±0.26) x 10-5and BR(τ-→ π-π0μ+μ-μτ-) = (2.094 ±0.004) x 10-6. These results have been obtained using the VEGAS routine to integrate numerically the phase space.