Quasifree Neutron Knockout from $^{54}\mathrm{Ca}$ Corroborates Arising $N=34$ Neutron Magic Number

S. Chen , J. Lee , P. Doornenbal , A. Obertelli (1) , C. Barbieri , Y. Chazono , P. Navrátil , K. Ogata , T. Otsuka , F. Raimondi (2) , V. Somà (1) , Y. Utsuno , K. Yoshida , H. Baba , F. Browne , D. Calvet (1) , F. Château (1) , N. Chiga , A. Corsi (1) , M.L. Cortés , A. Delbart (1) , J.M. Gheller (1) , A. Giganon (1) , A. Gillibert (1) , C. Hilaire (1) , T. Isobe , J. Kahlbow , T. Kobayashi , Y. Kubota , V. Lapoux (1) , H.N. Liu (1) , T. Motobayashi , I. Murray (3) , H. Otsu , V. Panin , N. Paul (1) , W. Rodriguez , H. Sakurai , M. Sasano , D. Steppenbeck , L. Stuhl , Y.L. Sun (1) , Y. Togano , T. Uesaka , K. Wimmer , K. Yoneda , N. Achouri (1) , O. Aktas , T. Aumann , L.X. Chung , F. Flavigny (3) , S. Franchoo (3) , I. Gašparić , R.B. Gerst , J. Gibelin (4) , K.I. Hahn , D. Kim , T. Koiwai , Y. Kondo , P. Koseoglou , C. Lehr , B.D. Linh , T. Lokotko , M. Maccormick (3) , K. Moschner , T. Nakamura , S.Y. Park , D. Rossi , E. Sahin , D. Sohler , P.A. Söderström , S. Takeuchi , H. Törnqvist , V. Vaquero , V. Wagner , S. Wang , V. Werner , X. Xu , H. Yamada , D. Yan , Z. Yang , M. Yasuda , L. Zanetti

1 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
2 CEA - Commissariat à l'énergie atomique et aux énergies alternatives
3 IPNO - Institut de Physique Nucléaire d'Orsay
4 LPCC - Laboratoire de physique corpusculaire de Caen

Exclusive cross sections and momentum distributions have been measured for quasifree one-neutron knockout reactions from a Ca54 beam striking on a liquid hydrogen target at ∼200  MeV/u. A significantly larger cross section to the p3/2 state compared to the f5/2 state observed in the excitation of Ca53 provides direct evidence for the nature of the N=34 shell closure. This finding corroborates the arising of a new shell closure in neutron-rich calcium isotopes. The distorted-wave impulse approximation reaction formalism with shell model calculations using the effective GXPF1Bs interaction and ab initio calculations concur our experimental findings. Obtained transverse and parallel momentum distributions demonstrate the sensitivity of quasifree one-neutron knockout in inverse kinematics on a thick liquid hydrogen target with the reaction vertex reconstructed to final state spin-parity assignments.

Mots clés: Nuclear Physics

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

S. Chen, J. Lee, P. Doornenbal, A. Obertelli, C. Barbieri, et al.. Quasifree Neutron Knockout from $^{54}\mathrm{Ca}$ Corroborates Arising $N=34$ Neutron Magic Number. Physical Review Letters, 2019, 123 (14), pp.142501. ⟨10.1103/PhysRevLett.123.142501⟩. ⟨hal-02338369⟩