Low-lying structure and shape evolution in neutron-rich Se isotopes

Chen, S.*; Doornenbal, P.*; Obertelli, A.*; Rodriguez, T. R.*; Authelet, G.*; Baba, Hidetada*; Calvet, D.*; Chteau, F.*; Corsi, A.*; Delbart, A.*; Gheller, J.-M.*; Giganon, A.*; Gillibert, A.*; Lapoux, V.*; Motobayashi, Toru*; Niikura, Megumi*; Paul, N.*; Rouss, J.-Y.*; Sakurai, Hiroyoshi*; Santamaria, C.*; Steppenbeck, D.*; Taniuchi, R.*; Uesaka, T.*; Ando, T.*; Arici, T.*; Blazhev, A.*; Browne, F.*; Bruce, A. M.*; Carroll, R.*; Chung, L. X.*; Corts, M. L.*; Dewald, M.*; Ding, B.*; Flavigny, F.*; Franchoo, S.*; Grska, M.*; Gottardo, A.*; Jungclaus, A.*; Lee, J.*; Lettmann, M.*; Linh, B. D.*; Liu, J.*; Liu, Z.*; Lizarazo, C.*; Momiyama, S.*; Moschner, K.*; Nagamine, S.*; Nakatsuka, N.*; Nita, C. R.*; Nobs, C.*; Olivier, L.*; Orlandi, R.  ; Patel, Z.*; Podolyk, Zs.*; Rudigier, M.*; Saito, T.*; Shand, C.*; Sderstrm, P.-A.*; Stefan, I.*; Vaquero, V.*; Werner, V.*; Wimmer, K.*; Xu, Z.*

Neutron-rich isotopes of selenium, Se, where studied via in beam -ray spectroscopy after nucleon removal reactions at RIBF in RIKEN. The low-energy excitations of these nuclei were investigated using - coincidences, and the first and second excited 2 states were found at remarkably low energies. The analysis and comparison with self-consistent beyond-mean field calculations suggest that both shape coexistence and triaxiality are needed to describe these isotopes.