A dispersive analysis of the decays tau->nu (2pi/2K/3pi)

by Sergi Gonzalez Solis (Indiana University)

Thursday 26 Sep 2019, 14:30 → 16:00 Europe/Madrid

IFAE seminar room (IFAE)

The τ is the only lepton massive enough to decay into hadrons. Its hadronic decays provide a privileged scenario to study low-energy effects of the strong interactions under rather clean conditions. Such advantageous  framework is used to improve our understanding of the hadronization of QCD currents, to study meson form factors and to extract the physical parameters of the intermediate resonances produced in the decay. In this talk, we will study its decays into π−π0 and K−KS, and the higher-multiplicity 3π decay mode. While the former allow to determine the resonance parameters of the ρ(770), ρ(1450) and ρ(1700), the latter offers a good environment to study the three-pion dynamics. Our theoretical description of the meson from factors that come up into play is based on Chiral Perturbation Theory supplemented by constraints posed by analyticity and unitarity through dispersion relations. The fantastic possibilities offered by the Belle-II experiment to study τ physics and low multiplicity final states with high precision make these studies of timely interest.

Talk_IFAE.pdf