Speaker
Description
Studying the nuclei along and near the N=Z line is the best way to find answers to some fundamental questions in nuclear physics, such as charge-dependence of the nuclear interaction [1,2]. The differences between the isobaric analogue states act as a magnifying glass on the structural changes in the mirror nuclei as a function of angular momentum. For instance, it has been demonstrated [3] that the mirror energy differences give a direct insight into the neutron skin. In fact, the skin changes along the rotational bands are strongly correlated with the difference between the neutron and proton occupations of the s1/2 halo orbit in nuclei of the sd shell. Such correlation has been so far found in the T=1/2 mirror pairs. Now we explore this feature in the T=3/2 mirrors.
Studying the T=3/2 mirrors is challenging from the experimental point of view, since it is difficult to produce the yrast bands of the most neutron-deficient partners. To reach those, for the first time we used a the 3-neutron channel in fusion-evaporation reactions. In this talk, the first results of such experiments, performed with the JUROGAM III - MARA spectrometer at JYFL, Jyväskylä will be shown. In particular, the production and spectroscopy of 29S, will be presented. This study allowed us to extend the level scheme of 29S to medium-high spin states, and thus to obtain for the first time the neutron skin in the T=3/2 partners and to explore the correlation with the occupation of the s1/2 halo orbit, by means of the measured mirror energy differences in a systematic analysis. In addition, we have been able to extract for the first time in this mass region, the 3-neutron evaporation cross-sections. The resulting mirror energy differences will be discussed in terms of neutron skin thickness extending, for the first time, our understanding to nuclei with 3 proton excess with respect to N=Z.
[1] M. A. Bentley and S. M. Lenzi, Prog. Part. Nucl. Phys. 59, 497 (2007)
[2] A. P. Zuker et al., Phys. Rev. Lett. 89, 142502 (2002)
[3] A. Boso et al. Phys. Rev. Lett. 121, 032502 (2018)