## Dispersive representation of the two-pion vector form factor

Speaker: Pablo Roig Garcés, UAB & IFAE

Speaker arrival: 19/06/2013

Speaker departure: 20/06/2013

Assigned office: 23

Title: Dispersive representation of the two-pion vector form factor

Place: Seminario Dpto. Física Teórica y del Cosmos

Date: 20/06/2013

Time: 12:00

Abstract:
A dispersive representation of the charged pion vector form factor fulfilling chiral symmetry, which is analytic and unitary, is proposed. Unknown parameters are fitted to the very precise Belle data on $\tau^-\to\pi^-\pi^0\nu_\tau$ decays. As a result, the rho(770) mass and width pole parameters and the LECs are determined accurately. The significance of isospin breaking corrections will also be discussed. For larger energies, this representation is complemented with a phenomenological description to allow its implementation in the new hadronic currents in TAUOLA, the standard MC generator for tau decays. A brief outlook on the results for the neutral form factor will be given.