Dispersive analysis of tau- -> pi- pi0 nu_tau Belle data

DANIEL GOMEZ DUMM; PABLO ROIG

Nagoya

Workshop; The Twelfth International Workshop on Tau-Lepton Physics (TAU2012); 2012

We analyse Belle data on the decay tau- -> pi- pi0 nu_tau using a dispersive representation of the vector form factor which is consistent with chiral symmetry and preserves analyticity and unitarity exactly. We fit the unknown theoretical parameters from the data, determining the values of the related low-energy observables r2^pi_V and c^pi_V. The implementation of isospin breaking effects is also discussed.