Nuclear structure of17Neby the three-neutron pickup(3He,6He)reaction

Abstract

The nuclear structure of ${}^{17}\mathrm{Ne}$ has been studied by the ${}^{20}{\mathrm{N}\mathrm{e}(}^{3}{\mathrm{H}\mathrm{e},}^{6}{\mathrm{H}\mathrm{e})}^{17}\mathrm{Ne}$ reaction at 70 MeV. Thirteen levels were identified in ${}^{17}\mathrm{Ne},$ and angular distributions have been measured for the first time for this reaction. Based on the observed transferred angular momentum dependence of the angular distributions, a spin-parity assignment has been made for several states in ${}^{17}\mathrm{Ne}.$ With the inclusion of the data on ${}^{17}\mathrm{Ne},$ $T=\frac{3}{2}$ quartet analog states have been completed for six levels in the $A=17$ isobar system. The level shifts in these $A=17$ nuclei are analyzed in terms of the isobaric multiplet mass equation (IMME). The results of such an analysis show a slight linear dependence of the $b$ and $c$ coefficients of the equation on the excitation energy. The coefficients for the positive parity states seem to follow a different systematics than the negative parity states, suggesting that these parity-dependent level shifts are reflecting the structure change. These coefficients of the IMME are discussed.