Coulomb displacement energies and nuclear sizes

The nuclear surface

“…Similarly Friedman and Mandelbaum (1969) have analysed 60Ni, 90Zr, 120Sn and zosPb and again produce no evidence for a 'neutron skin'. A most complete account of the corrections required is given by Auerbach et al (1969) who, in addition, represent the neutron excess by a single-particle wave function generated in a Saxon-Woods potential.…”

“…These results are rather surprising since the neutron skin is roughly constant, from Ni to Pb, and large, N 0.7 fm. The analysis has been criticized by Friedman (1969) on the grounds that their derivation of the potential from the two-body interaction is too simple and overestimates the interior contribution relative to that from the surface region. potential, d the two-body interaction and m the nuclear matter, should therefore be modified by a weighting factor which reduces the contribution from the central region in computing (r2),, which term we will now call (r2)meff; it is in fact bigger than the original term for a given nuclear size.…”

“…Friedman goes on to calculate these effects using a suitable two-body interaction, namely that of Kallio and Kolltveit (1964), with a density-dependent factor introduced, of the form (1ap) where p is the density of nuclear matter at the appropriate point and a is calculated by Green (1967) and is positive. His results are given in table 7(a) where they are also compared with ( ~~~~) ~/ 9 , the rms radius of the excess neutrons (over protons) as determined from Coulomb displacement energies - Friedman and Mandelbaum (1969)-which technique will be described later. His conclusion is that at present there is little evidence of a neutron skin in the analysis of nucleon scattering.…”

“…t The proton data are taken (indirectly) from Acker et aZ. (1966); the first set of neutron data are deduced fromGreenlees et al (1968) after applying a correction discussed in text; the second set is fromFriedman and Mandelbaum (1969) and refers to the excess neutrons.…”