[PRad] Proton Radius LQCD Calculations

[Patrick Achenbach]

Dear all,
I am not sure if it has been discussed before in this group. The latest lattice QCD calculations of the e.m. FFs have achieved uncertainties comparable to ep scattering data uncertainties. You can have a look at the below referenced PRL and its companion paper in PRD.

Best regards,
Patrick

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.211901


https://journals.aps.org/prd/abstract/10.1103/PhysRevD.109.094510
Electromagnetic form factors of the nucleon from ${N}_{f}=2+1$ lattice QCD<https://journals.aps.org/prd/abstract/10.1103/PhysRevD.109.094510>
There is a long-standing discrepancy between different measurements of the electric and magnetic radii of the proton. Lattice QCD calculations are a well-suited tool for theoretical investigations of the structure of the nucleon from first principles. However, all previous lattice studies of the proton's electromagnetic radii have either neglected quark-disconnected contributions or were not extrapolated to the continuum and infinite-volume limit. Here, we present results for the electromagnetic form factors of the proton and neutron computed on the ($2+1$)-flavor coordinated lattice simulations (CLS) ensembles including both quark-connected and -disconnected contributions. From simultaneous fits to the ${Q}^{2}$-, pion-mass, lattice-spacing, and finite-volume dependence of the form factors, we determine the electric and magnetic radii and the magnetic moments of the proton and neutron. For the proton, we obtain as our final values $⟨{r}_{E}^{2}{⟩}^{p}=(0.672\\ifmmode\\pm\\else\\textpm\\fi{}0.014(\\mathrm
journals.aps.org

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.jlab.org/pipermail/prad/attachments/20240705/a89d4073/attachment-0001.html>