Shell evolution beyond Z = 28 and N = 50: Spectroscopy of $^{81,82,83,84}$Zn

C.M. Shand , Zs. Podolyák , M. Górska , P. Doornenbal , A. Obertelli (1) , F. Nowacki (2) , T. Otsuka , K. Sieja (2) , J.A. Tostevin , Y. Tsunoda , G. Authelet (1) , H. Baba , D. Calvet (1) , A. Château (1) , S. Chen , A. Corsi (1) , A. Delbart (1) , J.M. Gheller (1) , A. Giganon (1) , A. Gillibert (1) , T. Isobe , V. Lapoux (1) , M. Matsushita , S. Momiyama , T. Motobayashi , M. Niikura , H. Otsu , N. Paul (1) , C. Péron (1) , A. Peyaud (1) , E.C. Pollacco (1) , J.-Y. Roussé (1) , H. Sakurai , C. Santamaria (1) , M. Sasano , Y. Shiga , D. Steppenbeck , S. Takeuchi , R. Taniuchi , T. Uesaka , H. Wang , K. Yoneda , T. Ando , T. Arici , A. Blazhev , F. Browne , A.M. Bruce , R.J. Carroll , L.X. Chung , M.L. Cortés , M. Dewald , B. Ding , Zs. Dombrádi , F. Flavigny (3) , S. Franchoo (3) , F. Giacoppo , A. Gottardo (3) , K. Hadyńska-Klęk , A. Jungclaus , Z. Korkulu , S. Koyama , Y. Kubota , J. Lee , M. Lettmann , B.D. Linh , J. Liu , Z. Liu , C. Lizarazo , C. Louchart , R. Lozeva (2, 4) , K. Matsui , T. Miyazaki , K. Moschner , M. Nagamine , N. Nakatsuka , S. Nishimura , C.R. Nita , C.R. Nobs , L. Olivier (3) , S. Ota , R. Orlandi , Z. Patel , P.H. Regan , M. Rudigier , E. Şahin , T. Saito , P.-A. Söderström , I. Stefan (3) , T. Sumikama , D. Suzuki (3) , Zs. Vajta , V. Vaquero , V. Werner , K. Wimmer , J. Wu , Z.Y. Xu

1 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
2 IPHC - Institut Pluridisciplinaire Hubert Curien
3 IPNO - Institut de Physique Nucléaire d'Orsay
4 CSNSM - Centre de Sciences Nucléaires et de Sciences de la Matière

We report on the measurement of new low-lying states in the neutron-rich 81,82,83,84 Zn nuclei via in-beam γ -ray spectroscopy. These include the 41+→21+ transition in 82 Zn, the 21+→0g.s.+ and 41+→21+ transitions in 84 Zn, and low-lying states in 81,83 Zn were observed for the first time. The reduced E(21+) energies and increased E(41+)/E(2+1) ratios at N=52 , 54 compared to those in 80 Zn attest that the magicity is confined to the neutron number N=50 only. The deduced level schemes are compared to three state-of-the-art shell model calculations and a good agreement is observed with all three calculations. The newly observed 2+ and 4+ levels in 84 Zn suggest the onset of deformation towards heavier Zn isotopes, which has been incorporated by taking into account the upper sdg orbitals in the Ni78-II and the PFSDG-U models.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

C.M. Shand, Zs. Podolyák, M. Górska, P. Doornenbal, A. Obertelli, et al.. Shell evolution beyond Z = 28 and N = 50: Spectroscopy of $^{81,82,83,84}$Zn. Phys.Lett.B, 2017, 773, pp.492-497. ⟨10.1016/j.physletb.2017.09.001⟩. ⟨hal-01645772⟩