Ground-state -decay spectroscopy of Ta

Mukai, Momo*; Hirayama, Yoshikazu*; Watanabe, Yutaka*; Watanabe, Hiroshi*; Koura, Hiroyuki   ; Jeong, S. C.*; Miyatake, Hiroari*; Brunet, M.*; Ishizawa, Satoshi*; Kondev, F. G.*; Lane, G. J.*; Litvinov, Yu. A.*; Niwase, Toshitaka*; Oyaizu, Mitsuhiro*; Podolyk, Zs.*; Rosenbusch, M.*; Schury, P.*; Wada, Michiharu*; Walker, P. M.*

Beta-decay spectroscopy of the Ta ground state was performed at the KEK Isotope Separation System. -delayed rays corresponding to the previously reported in-beam transitions were observed. The -decay half-life of the Ta ground state was determined to be 283(10) s by analyzing a time spectrum of - coincidence events. The -decay branching ratio and log() values were evaluated for the first time. Based on the newly evaluated log() values of 6.0 and a decay scheme, spin-parity values of I = 7/2 originating from the odd-proton orbit 7/2[404] were assigned with high confidence, which is consistent with the systematics of neighboring odd-A nuclides.