Measurements of interaction cross sections for^22–35Na isotopes

Abstract

Abstract. Interaction cross sections (σ I ) for 22−35 Na isotopes from the stability line to the vicinity of the neutron drip line have been measured at around 240 MeV/nucleon. The σ I for 33−35 Na were measured for the first time. Enhancement in cross sections is clearly observed from the systematics for stable nuclei, for isotopes with large mass numbers. From the known values of the nuclear-deformation parameters β 2 of 22−31 Na, these enhancement can be mainly ascribed to the nuclear deformation. Large enhancement in heavier isotopes suggest that these nuclei are strongly deformed. The root-mean-square (RMS) nuclear matter radii were deduced from the σ I by using Glauber-type calculation. Furthermore, a monotonic growth of the neutron-skin thickness has been deduced with increasing neutron number for Na isotopes.

Nuclear charge radii of Na isotopes: A tale of two theories

“…In principle, elastic electron scattering experiments offer a model-independent access to radii and other moments of the nuclear charge distribution, however, for the S-D shell nuclei, their results have large Eq. ( 4) [18,19] Eq. ( 5)…”

“…with R p = 0.8414 (19) fm the latest CODATA value for the RMS charge radius of the proton [78], and R 2 n = −0.116(2) fm 2 that of the neutron [79]. The last term is the Darwin-Foldy correction [80].…”

“…However, it has been a major challenge to perform accurate atomic calculations required to extract the nuclear charge radii values from the experimental data. For this reason, Na isotopes are some of the rare cases where matter radii are known with higher precision than charge radii [18,19].…”

“…Instead of comparing directly with the matter radii, the neutron skin, defined as the difference between its proton and neutron radii, r np = r n − r p , can be used to establish physical limits for the atomic parameters. Figure 1 shows the nuclear theory results for r np alongside the semi-empirical results obtained using available matter radii [18,19], our calculated F = −39.2(3) MHz/fm 2 and spin-orbit corrections, and charge radii values extracted from the IS data using different values of the atomic parameter K SMS . As r c is extremely sensitive to K SMS , we vary this parameter, while keeping F constant, and compare the extracted neutron skin with the accurate theoretical prediction.…”

“…Semi-empirical estimation of KSMS. We compare the calculated rnp from TableII(filled band), with rnp deduced from: matter radii (taken from[18,19]), the field shift given in this work, and calculated spin orbit corrections. The comparison is done for different values of KSMS, and returns: KSMS = 105.3(1.3) GHz amu.…”