2025/10/28 by Briceño, Raúl A., Hansen, Maxwell T., Jackura, Andrew W. +2
#FOS: Physical sciences #High Energy Physics - Lattice (hep-lat) #High Energy Physics - Phenomenology (hep-ph) #High Energy Physics - Theory (hep-th) #Nuclear Theory (nucl-th)
paper · doi:10.48550/arxiv.2510.24894
This work presents a lattice quantum chromodynamics (QCD) determination of πππ scattering amplitudes for the isospin-2 channel with angular momentum and parity JP = 1+. The calculation is performed using unphysically heavy light-quark masses, corresponding to a pion mass of mπ ≈ 400~MeV, for which the ρ meson manifests as a narrow resonance. The analysis employs a previously developed formalism that non-perturbatively relates the finite-volume spectra of two- and three-pion systems to their infinite-volume scattering amplitudes. We combine earlier lattice QCD results for ππ systems with isospins 1 and 2 with new determinations of the isospin-2 three-pion finite-volume spectrum, obtained for three cubic, periodic lattice volumes with box length ranging from ≈ 4/mπ to 6/mπ. These combined data constrain the low-lying partial waves of the infinite-volume three-pion K matrix, from which we solve a set of coupled integral equations to extract the corresponding scattering amplitudes.