Abstract
The highest spin states in a T(z)=1/2 nucleus have been observed in 77Sr: I(pi)=(49/2+) and (29/2-). In addition, states up to I(pi)=(22+) have been seen in 78Sr. The alpha=1/2, g9/2 band and both signature partners of the negative parity band in 77Sr were found to be identical to the yrast band in 78Sr with relative alignments of 1.22(7)HBAR, 0.52(5)HBAR (alpha=1/2), and 0.42(4)HBAR (alpha=-1/2), respectively. In one of the negative parity bands, the identicality persists through the first proton band crossing. The odd spin decay sequence of the 4- band in 78Rb is identical to the ground band of 78Sr [3.02(3)HBAR] at low spin and to the alpha=1/2, g9/2 band in 77Rb [1.11(3)HBAR] at higher spins. These are the only known examples of identical bands in the neutron deficient A=80 region. The analysis indicates that the [301]3/2 Nilsson orbital is a very good spectator orbital.