Elastic nucleon-pion scattering at m = 200 MeV from lattice QCD

Elastic nucleon-pion scattering amplitudes are computed using lattice QCD on a single ensemble of gauge field configurations with Nf=2+1 dynamical quark flavors and mπ=200MeV. The s-wave lengths both total isospins I=1/2 I=3/2 inferred from the finite-volume spectrum below inelastic threshold together p-wave containing Δ(1232) resonance. well-described by effective range expansion parameters constrained fits to energy levels, enabling determination length statistical errors 5%, while is somewhat less precisely evaluated. Systematic due excited states influence higher partial waves controlled, providing step toward future computations down physical light masses multiple spacings volumes.