K selection in the decay of the (ν 52 [532]- 32 [411])4- isomeric state in Zr 102

Abstract

The (ν52[532]- 32[411]) 4- state in Zr102, populated in the β decay of Y102, has been measured to be isomeric with a mean lifetime of 9.5(7) ns. It decays via four transitions, two of which are ΔK=2 (to the 3+ and 4+ members of the 2γ+ band) and one is ΔK=4 (to the 4+ member of the ground state 0+ band). The fourth (low-energy) transition is inferred to decay to an as-yet unassigned state. Hindrances of 106 were derived for the ΔK=2 transitions compared to Weisskopf estimates and the ΔK=4 transition hindered by a factor of 109. These values are consistent with the decay pattern of the analogous isomeric state in the neighboring N=62 nucleus Sr100 and with the broader systematics of such transitions. A comparison of the hindrances for the ΔK=4 transitions suggests that Zr102 is hardened against the γ degree of freedom compared to Sr100.