Computing the nucleon Dirac radius directly at $Q^2=0$

TL;DR

This paper introduces a lattice method for directly calculating the nucleon Dirac radius at zero momentum transfer, utilizing the Rome method and addressing excited-state contamination.

Contribution

It presents a novel lattice approach for directly computing momentum derivatives of nucleon matrix elements at $Q^2=0$, applied to physical pion mass simulations.

Findings

Preliminary results for the isovector magnetic moment and Dirac radius.

Use of the summation method to mitigate excited-state contamination.

Application at the physical pion mass with a 2HEX-smeared Wilson-clover action.

Abstract

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.