τ→(3π)ντand light-meson spectroscopy

The 3π spectrum in τ decay is studied by considering the contribution from the radially excited state ($a_1^{\mathcal{’}}$) of the $a_1$ meson. It is shown that the spectrum is reasonably reproduced by the following values of the $a_1$ and &=1.08–1.14 &=0.36–0.40 GeV, & =1.51–1.59 GeV, and &=0.50–0.55 GeV or 0.75–0.90 GeV depending on the models for multiparticle decay modes. The implications of these results are discussed in connection with the classification of light mesons with masses below 2 GeV.