Nucleon structure near the physical pion mass
MIT Lab for nuclear science
Lattice QCD calculations of nucleon structure using pion masses as low as 149 MeV will be presented. Because of work done to reduce excited-state contaminations, the results agree with experiment for four key isovector observables: the Dirac and Pauli radii, the magnetic moment, and the quark momentum fraction; however, a discrepancy remains for the axial charge, and evidence suggesting a likely cause will be shown. Understanding these sources of error helps to increase confidence in predictions of the tensor and scalar charge.