English

A First Glimpse at the Shell Structure beyond $^{54}$Ca: Spectroscopy of $^{55}$K, $^{55}$Ca, and $^{57}$Ca

Nuclear Experiment 2022-03-14 v1

Abstract

States in the N=35N=35 and 37 isotopes 55,57^{55,57}Ca have been populated by direct proton-induced nucleon removal reactions from 56,58^{56,58}Sc and 56^{56}Ca beams at the RIBF. In addition, the (p,2p)(p,2p) quasi-free single-proton removal reaction from 56^{56}Ca was studied. Excited states in 55^{55}K, 55^{55}Ca, and 57^{57}Ca were established for the first time via in-beam γ\gamma-ray spectroscopy. Results for the proton and neutron removal reactions from 56^{56}Ca to states in 55^{55}K and 55^{55}Ca for the level energies, excited state lifetimes, and exclusive cross sections agree well with state-of-the-art theoretical calculations using different approaches. The observation of a short-lived state in 57^{57}Ca suggests a transition in the calcium isotopic chain from single-particle dominated states at N=35N=35 to collective excitations at N=37N=37.

Keywords

Cite

@article{arxiv.2202.03050,
  title  = {A First Glimpse at the Shell Structure beyond $^{54}$Ca: Spectroscopy of $^{55}$K, $^{55}$Ca, and $^{57}$Ca},
  author = {T. Koiwai and K. Wimmer and P. Doornenbal and A. Obertelli and C. Barbieri and T. Duguet and J. D. Holt and T. Miyagi and P. Navrátil and K. Ogata and N. Shimizu and V. Somà and Y. Utsuno and K. Yoshida and N. L. Achouri and H. Baba and F. Browne and D. Calvet f and F. Château and S. Chen and N. Chiga and A. Corsi and M. L. Cortés and A. Delbart and J. -M. Gheller and A. Giganon and A. Gillibert and C. Hilaire and T. Isobe and T. Kobayashi and Y. Kubota and V. Lapoux and H. N. Liu and T. Motobayashi and I. Murray and H. Otsu and V. Panin and N. Paul and W. Rodriguez and H. Sakurai and M. Sasano and D. Steppenbeck and L. Stuhl and Y. L. Sun and Y. Togano and T. Uesaka and K. Yoneda and O. Aktas and T. Aumann and L. X. Chung and F. Flavigny and S. Franchoo and I. Gasparic and R. -B. Gerst and J. Gibelin and K. I. Hahn and D. Kim and Y. Kondo and P. Koseoglou and J. Lee and C. Lehr and B. D. Linh and T. Lokotko and M. MacCormick and K. Moschner and T. Nakamura and S. Y. Park and D. Rossi and E. Sahin and P-A. Söderström and D. Sohler and S. Takeuchi and H. Toernqvist and V. Vaquero and V. Wagner and S. Wang and V. Werner and X. Xu and H. Yamada and D. Yan and Z. Yang and M. Yasuda and L. Zanetti},
  journal= {arXiv preprint arXiv:2202.03050},
  year   = {2022}
}

Comments

accepted Phys. Lett. B