Fig. 2

Proton radii. Results are shown for carbon, beryllium, boron and oxygen isotopes. The red-filled and black-filled circles are, respectively, the proton radii from this and our recent work^32,33,34,37. The open diamonds are the data from electron-scattering and isotope-shift methods¹². The error bars for the red-filled circles include the statistical and experimental systematic uncertainties, as well as the uncertainties due to the choice of density distributions. The error bars for other experimental data are taken from the literature. The small symbols connected with dashed and dotted lines are the predictions from the AMD¹⁹ and RMF³⁸ models, respectively. The small blue symbols with solid and dash-dotted lines are the results from the ab initio coupled-cluster calculations with NNLO_sat³⁹ and the NN-only interaction NNLO_opt⁴⁰