Proton scattering on the radioactive nucleus O and the 0gs+→21+ transition in the neutron-rich oxygen isotopes

Decoupling of valence neutrons from the core in 16C

“…This nucleus was investigated by several methods and the weighted mean of extracted M n /M p ratios is around 2, which slightly exceeds the isoscalar value of 1.25 [3]. A larger ratio of M n /M p around 3 was found for 20 O [2,3]. Our present value, 7.6 ± 1.7 represents the largest deviation from the "normal" isoscalar case observed so far.…”

“…Another interesting reference may be the value obtained for 18 O, which is also a nucleus consisting of a neutron closed shell plus two valence neutrons. This nucleus was investigated by several methods and the weighted mean of extracted M n /M p ratios is around 2, which slightly exceeds the isoscalar value of 1.25 [3]. A larger ratio of M n /M p around 3 was found for 20 O [2,3].…”

“…By comparing the results of proton inelastic scattering and Coulomb excitation measurements, a large difference between proton and neutron transition matrix elements has been observed in the case of 20 O [2,3]. Recent calculations [4] suggest different deformations for proton and neutron distributions in carbon nuclei, as well.…”

“…In a simple shell-model picture allowing for only two valence neutrons above a closed 14 C core, the amount of core polarization can be estimated as [3] (2)…”

Large-amplitudeQn-Qpcollectivity in the neutron-rich oxygen isotopeSeveryukhin1, Bender2, Flocard3 et al. 2007Phys. Rev. C3020View full textAdd to dashboardCite

“…The strong proton shell closure at Z = 8 and the already good experimental knowledge of the complete oxygen isotope series from 16 O up to the drip line at 24 O [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18] makes Oxygen an attractive element for a first investigation (not to mention that the theoretical analysis is significantly simplified in light systems). In fact, the experimental effort on these isotopes has spurred a number of analysis based either on the mean-field method [13,19,20,21,22,23,24] or on the shell model [18,25,26,27].…”