Elastic nucleon-pion scattering at = 200 MeV from lattice QCD
John Bulava (Deutsches Elektronen-Synchrotron DESY, Platanenallee 6, Zeuthen, Germany); Andrew D. Hanlon (Physics Department, Brookhaven National Laboratory, Upton, USA); Ben Hörz (Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, USA, Intel Deutschland GmbH, Dornacher Str. 1, Feldkirchen, Germany); Colin Morningstar (Dept. of Physics, Carnegie Mellon University, Pittsburgh, USA)
; Amy Nicholson (Dept. of Physics and Astronomy, University of North Carolina, Chapel Hill, USA); et al - Show all 9 authors
Elastic nucleon-pion scattering amplitudes are computed using lattice QCD on a single ensemble of gauge field configurations with dynamical quark flavors and . The s-wave scattering lengths with both total isospins and are inferred from the finite-volume spectrum below the inelastic threshold together with the p-wave containing the resonance. The amplitudes are well-described by the effective range expansion with parameters constrained by fits to the finite-volume energy levels, enabling a determination of the scattering length with statistical errors below 5%, while the scattering length is somewhat less precisely evaluated. Systematic errors due to excited states and the influence of higher partial waves are controlled, providing a step toward future computations down to physical light quark masses with multiple lattice spacings and volumes.
