π−a1mixing at intermediate energies

We describe the mixing of the $q\overline{q}$ pseudoscalar channel with the longitudinal $q\overline{q}$ axial-vector channel, making use of a generalized Nambu–Jona-Lasino model that includes a model of confinement. In addition to the pion, we find $J^P{=0\mathrm{}}^{-}$ states at 1.18, 1.36, 1.47, 1.63, and 1.68 GeV. The first three of these states are in the region of the π(1300) excitation that is assigned a mass of $1300\pm 100\mathrm{MeV}$ and a width of 200–600 MeV in the data tables. Our work, therefore, suggests the π(1300) may not represent a single state of $q\overline{q}$ character.