Speaker
Rafel Escribano
(Autonomous University of Barcelona)
Description
In a combined study of the decay spectra of τ−→KSπ−ντ and τ−→K−ηντ decays within a dispersive representation of the required form factors, we illustrate how the K∗(1410) resonance parameters, defined through the pole position in the complex plane, can be extracted with improved precision as compared to previous studies. While we obtain a substantial improvement in the mass, the uncertainty in the width is only slightly reduced, with the findings MK∗′=1304±17MeV and ΓK∗′=171±62MeV. Further constraints on the width could result from updated analyses of the Kπ and/or Kη spectra using the full Belle-I data sample. Prospects for Belle-II are also discussed. As the K−π0 vector form factor enters the description of the decay τ−→K−ηντ, we are in a position to investigate isospin violations in its parameters like the form factor slopes. In this respect also making available the spectrum of the transition τ−→K−π0ντ would be extremely useful, as it would allow to study those isospin violations with much higher precision.
Primary author
Rafel Escribano
(Autonomous University of Barcelona)
