Computing the nucleon Dirac radius directly at $Q^2=0$
N. Hasan, M. Engelhardt, J. Green, S. Krieg, S. Meinel, J. Negele, A. Pochinsky, S. Syritsyn
We describe a lattice approach for directly computing momentum derivatives of nucleon matrix
elements using the Rome method, which we apply to obtain the isovector magnetic moment
and Dirac radius. We present preliminary results calculated at the physical pion mass using a
2HEX-smeared Wilson-clover action. For removing the effects of excited-state contamination,
the calculations were done at three source-sink separations and the summation method was used.