Speaker
Description
In this talk, we present a numerical exploration of the relativistic field theory (RFT) formalism for three pions with all possible values of non-maximal isospin, $I_{\pi\pi\pi} = 2$, $1$, and $0$. Using the published generic-isospin extension of the RFT formalism and applying our open-source Python library to implement the formalism, we predict an array of three-pion energies for realistic values of the two-to-two scattering amplitudes. Considering all possible finite-volume irreps with three values of total momentum, we demonstrate how complicated spectra emerge, in particular from the mixing of all allowed two-pion isospins in a given sector of definite $I_{\pi \pi \pi}$. The present results restrict attention to the case of a vanishing intrinsic three-body interaction so that the spectra can be understood as a baseline. In future lattice QCD calculations, deviations from these values will translate to evidence of intrinsic three-particle effects.
