Combined analysis of the decays τ <sup>−</sup> → K <inf> S</inf> π <sup>−</sup> ν <inf> τ</inf> and τ <sup>−</sup> → K <sup>−</sup> ην <inf> τ</inf>

R. Escribano, S. González-Solís, M. Jamin, P. Roig

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© 2014, The Author(s). Abstract: 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 ± 17 MeV and ΓK*′ = 171 ± 62 MeV. 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.
Original languageEnglish
Article number42
JournalJournal of High Energy Physics
Issue number9
Publication statusPublished - 1 Jan 2014


  • Phenomenological Models
  • QCD Phenomenology


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