Model-independent determination of the nucleon charge radius from lattice QCD
Abstract
Lattice QCD calculations of nucleon form factors are restricted to discrete values of the Euclidean four-momentum transfer. Therefore, the extraction of radii typically relies on parametrizing and fitting the lattice QCD data to obtain its slope close to zero momentum transfer. We investigate a new method, which allows to compute the nucleon radius directly from existing lattice QCD data, without assuming a functional form for the momentum dependence of the underlying form factor. The method is illustrated for the case of the isovector mean-square charge radius of the nucleon ⟨risov2⟩ and the quark-connected contributions to ⟨rp2⟩ and ⟨rn2⟩ for the proton and neutron, respectively. Computations are performed using a single gauge ensemble with Nf=2 +1 +1 maximally twisted mass clover-improved fermions at physical quark mass and a lattice spacing of a =0.08 fm .
- Publication:
-
Physical Review D
- Pub Date:
- June 2020
- DOI:
- 10.1103/PhysRevD.101.114504
- arXiv:
- arXiv:2002.06984
- Bibcode:
- 2020PhRvD.101k4504A
- Keywords:
-
- High Energy Physics - Lattice;
- High Energy Physics - Phenomenology;
- Nuclear Experiment;
- Nuclear Theory
- E-Print:
- 19 pages, 9 figures and 2 tables, matching version accepted for publication in PRD