Finite-volume Hamiltonian method for coupled-channels interactions in lattice QCD

Abstract

Within a multichannel formulation of ππ scattering, we investigate the use of the finite-volume Hamiltonian approach to resolve scattering observables from lattice QCD spectra. The asymptotic matching of the well-known Lüscher formalism encodes a unique finite-volume spectrum. Nevertheless, in many practical situations, such as coupled-channels systems, it is advantageous to interpolate isolated lattice spectra in order to extract physical scattering parameters. Here we study the use of the Hamiltonian framework as a parametrization that can be fit directly to lattice spectra. We find that, with a modest amount of lattice data, the scattering parameters can be reproduced rather well, with only a minor degree of model dependence.