Isovector and flavor-diagonal charges of the nucleon

¹ Theoretical Division T-2, Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.A
² Computer, Computational, and Statistical Sciences CCS-7, Los Alamos National Laboratory, Los Alamos, NM 87545, U.S.A
³ Department of Physics and Astronomy, Michigan State University, MI 48824, U.S.A

^* Speaker, e-mail: rajan@lanl.gov, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, USA.

Published online: 26 March 2018

Abstract

We present an update on the status of the calculations of isovector and flavor-diagonal charges of the nucleon. The calculations of the isovector charges are being done using ten 2+1+1-flavor HISQ ensembles generated by the MILC collaboration covering the range of lattice spacings a ≈ 0.12, 0.09, 0.06 fm and pion masses M_π ≈ 310, 220, 130 MeV. Excited-states contamination is controlled by using four-state fits to two-point correlators and three-states fits to the three-point correlators. The calculations of the disconnected diagrams needed to estimate flavor-diagonal charges are being done on a subset of six ensembles using the stocastic method. Final results are obtained using a simultaneous fit in M²_π, the lattice spacing a and the finite volume parameter M_πL keeping only the leading order corrections.