In our theory of absolute physics where the constants should be in absolute values as we show in some of our preprints on RG, the most accurate experimental value currently is 0.8758 fm obtained before 2010 from hydrogenate. And according to our theory the experiments on muonic H-D are the best experiments to determine the neutron radius because the neutron radius should be absolutely obtain using the mounic protons and the most precise are these of the CREMA colloboration of 0.84087 from muonic H (hydrogen) and 0.8356 fm from muonic D (deuterium). According to our theory the size of the neutron remain absolutely stable in the experiments in muonic H-D.