Charge radii of the nucleon from its flavor dependent Dirac form factors
Temple University, 19122, Philadelphia, PA, USA
2 Argonne National Laboratory, 60439, Lemont, IL, USA
3 New Mexico State University, 88003, Las Cruces, NM, USA
Accepted: 6 February 2021
Published online: 21 February 2021
We have determined the proton and the neutron charge radii from a global analysis of the proton and the neutron elastic form factors, after first performing a flavor decomposition of these form factors under charge symmetry in the light cone frame formulation. We then extracted the transverse mean-square radii of the flavor dependent quark distributions. In turn, these are related in a model-independent way to the proton and neutron charge radii but allow us to take into account motion effects of the recoiling nucleon for data at finite but high momentum transfer. In the proton case we find , consistent with the proton charge radius obtained from muonic hydrogen spectroscopy [1, 2]. The current method improves on the precision of the extraction based on the form factor measurements. Furthermore, we find no discrepancy in the determination among the different electron scattering measurements, all of which, utilizing the current method of extraction, result in a value that is consistent with the smallest extraction from the electron scattering measurements . Concerning the neutron case, past results relied solely on the neutron-electron scattering length measurements, which suffer from an underestimation of underlying systematic uncertainties inherent to the extraction technique. Utilizing the present method we have performed the first extraction of the neutron charge radius based on nucleon form factor data, and we find .
© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2021