1209.1687 (J. R. Green et al.)

Nucleon Structure from Lattice QCD Using a Nearly Physical Pion Mass    [PDF]

J. R. Green, M. Engelhardt, S. Krieg, J. W. Negele, A. V. Pochinsky, S. N. Syritsyn

We report the first lattice QCD calculation using the almost physical pion mass mpi=149 MeV that agrees with experiment for four fundamental isovector observables characterizing the gross structure of the nucleon: the Dirac and Pauli radii, the magnetic moment, and the quark momentum fraction. The key to this success is excluding the contributions of excited states. An analogous calculation of the nucleon axial charge governing beta decay fails to agree with experiment, and we discuss possible sources of error.

View original: http://arxiv.org/abs/1209.1687