Scalar and tensor meson contributions to the τ→πππντ axial-vector form-factor
J.J. Sanz-Cillero* and O. Shekhovtsova
Pre-published on:
February 16, 2018
Published on:
March 20, 2018
Abstract
In these proceedings we study the scalar (JPC=0++, S) and tensor (JPC=2++, T) resonance contributions to the πππ axial-vector form-factor (AFF), relevant for phenomenological studies of tau decays. Chiral symmetry and its isospin subgroup are key ingredients of our construction, implemented via a chiral invariant Lagrangian which incorporates S, T and axial-vector (A) resonances and the light multiplet of pseudoscalars, the chiral Goldstones (pions, kaons and etas). Thus, one obtains the right isospin relation between the π0π0π− and π−π−π+ production amplitudes. The chiral invariant construction ensures the recovery of the low-energy limit, provided by Chiral Perturbation Theory (χPT) and the transversality of the current in the chiral limit at all energies. The amplitudes are further constrained by imposing high-energy constraints, prescribed by Quantum Chromodynamics (QCD). We discuss the improvement of the Breit-Wigner and Flatt\'e representations for the broad σ scalar resonance provided by the incorporation of the real logs required by analyticity, \`a la Gounaris-Sakurai. The aim of this work is to improve the description of these decay channels oriented to its implementation in the Tauola Monte Carlo and future Belle data analyses.
DOI: https://doi.org/10.22323/1.310.0185
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