Cross-shell states in 15C: A test for p-sd interactions

• DOI: 10.1016/j.physletb.2023.138149
• Publication Date: 2023-08-28T16:17:40Z
• Authors: J. Lois-Fuentes; B. Fernández-Domí...; X. Pereira-López; F. Delaunay; W.N. Catford; A. Matta; N.A. Orr; T. Duguet; T. Otsuka; V. Somà; O. Sorlin; T. Suzuki; N.L. Achouri; M. Assié; S. Bailey; B. Bastin; Y. Blumenfeld; R. Borcea; M. Caamaño; L. Caceres; E. Clément; A. Corsi; N. Curtis; Q. Deshayes; F. Farget; M. Fisichella; G. de France; S. Franchoo; M. Freer; J. Gibelin; A. Gillibert; G.F. Grinyer; F. Hammache; O. Kamalou; A. Knapton; Tz. Kokalova; V. Lapoux; B. Le Crom; S. Leblond; F.M. Marqués; P. Morfouace; J. Pancin; L. Perrot; J. Piot; E. Pollacco; D. Ramos; D. Regueira-Castro; C. Rodríguez-Tajes; T. Roger; F. Rotaru; M. Sénoville; N. de Séréville; R. Smith; M. Stanoiu; I. Stefan; C. Stodel; D. Suzuki; J.C. Thomas; N. Timofeyuk; M. Vandebrouck; J. Walshe; C. Wheldon
• Keywords: [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th]; Nuclear Theory; Physics; QC1-999; Phenomenological shell-model; FOS: Physical sciences; [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex]; 540; 530; Neutron-rich carbon isotopes; One neutron pick-up reaction; Nuclear Theory (nucl-th); Ab initio calculations; Nuclear Experiment (nucl-ex); Nuclear Experiment

The low-lying structure of $^{15}$C has been investigated via the neutron-removal $^{16}$C$(d,t)$ reaction. Along with bound neutron sd-shell hole states, unbound p-shell hole states have been firmly confirmed. The excitation energies and the deduced spectroscopic factors of the cross-shell states are an important measure of the $[(p)^{-1}(sd)^{2}]$ neutron configurations in $^{15}$C. Our results show a very good agreement with shell-model calculations using the SFO-tls interaction for $^{15}$C. However, a modification of the $p$-$sd$ and $sd$-$sd$ monopole terms was applied in order to reproduce the $N=9$ isotone $^{17}$O. In addition, the excitation energies and spectroscopic factors have been compared to the first calculations of $^{15}$C with the $ab~ initio$ self-consistent Green's function method employing the NNLO$_{sat}$ interaction. The results show the sensitivity to the size of the $N=8$ shell gap and highlight the need of going beyond the current truncation scheme in the theory.