We report on the first in-beam γ-ray spectroscopy of the proton-dripline nucleus 40Sc using two-nucleon pickup onto an intermediate-energy rare-isotope beam of 38Ca. The 9Be(38Ca,40Sc+γ)X reaction at 60.9 MeV/nucleon mid-target energy selectively populates states in 40Sc for which the transferred proton and neutron couple to high orbital angular momentum. In turn, due to angular-momentum selection rules in proton emission and the nuclear structure and energetics of 39Ca, such states in 40Sc then exhibit γ-decay branches although they are well above the proton separation energy. This work uniquely complements results from particle spectroscopy following charge-exchange reactions on 40Ca as well as 40Ti EC/β+ decay which both display very different selectivities. The population and γ-ray decay of the previously known first (5−) state at 892 keV and the observation of a new level at 2744 keV are discussed in comparison to the mirror nucleus and shell-model calculations. On the experimental side, this work shows that high-resolution in-beam γ-ray spectroscopy is possible with new generation Ge arrays for reactions induced by rare-isotope beams on the level of a few μb of cross section.
@article{arxiv.2007.11683,
title = {In-beam $\gamma$-ray spectroscopy at the proton dripline: $^{40}$Sc},
author = {A. Gade and D. Weisshaar and B. A. Brown and J. A. Tostevin and D. Bazin and K. Brown and R. J. Charity and P. J. Farris and A. M. Hill and J. Li and B. Longfellow and W. Reviol and D. Rhodes},
journal= {arXiv preprint arXiv:2007.11683},
year = {2020}
}