Model-independent determination of the magnetic radius of the proton from spectroscopy of ordinary and muonic hydrogen

الأصل · EN

To date the magnetic radius of the proton has been determined only by means of electron-proton scattering, which is not free of controversies. Any existing atomic determinations are irrelevant because they are strongly model-dependent. We consider a so-called Zemach contribution to the hyperfine interval in ordinary and muonic hydrogen and derive a self-consistent model-independent value of the magnetic radius of the proton. More accurately, we constrain not a value of the magnetic radius by itself, but its certain combination with the electric-charge radius of the proton, namely, Rₑ²+Rₘ². The result from the ordinary hydrogen is found to be Rₑ²+Rₘ²=1.35(12) fm², while the derived muonic value is 1.49(18) fm². That allows us to constrain the value of the magnetic radius of proton Rₘ=0.78(8) fm at the 10% level.