Tau decay and the structure of the a1

Abstract

We analyse the decay $\tau \to \pi \pi \pi \nu$ based on the recently developed techniques to generate axial-vector resonances dynamically. Under the assumption that the a1 is a coupled-channel meson-molecule, the spectral function is described surprisingly well by adjusting only one free parameter. Including, in addition, an elementary a1 corrupts the results.

Replaced figures, due to an error in the calculation, which we corrected. (Conclusions did not change.) Dropped last part discussing higher order effect in favour of further elucidation

References in corpus (1)

• Information on the structure of the a1 from tau decay

Cited by in corpus (2)

• On the radiative decays of light vector and axial-vector mesons
• Why the $a_1$ meson might be a difficult messenger for the restoration of chiral symmetry