Nuclear Structure and Decay Data for A=44 Isobars

Abstract

Experimental nuclear spectroscopic data are evaluated for 12 known nuclides of mass number A=44 (Si, P, S, Cl, Ar, K, Ca, Sc, Ti, V, Cr, Mn). Detailed evaluated information are presented for each reaction and decay. Recommended values combining all available data are provided for all spectroscopic properties of each level, γ-ray, and decay radiation. No excited states have yet been identified in 44Si, 44P, 44Cr, and 44Mn. Information for excited states in 44Cl and 44V are limited. Nuclides of 44S, 44Ar and 44K have been studied via only a few reactions and decays, while 44Ca, 44Sc and 44Ti are the most investigated nuclides through various reactions and decays. Evaluators note that the half-life of the g.s. of 44S has been measured independently, with fairly good statistics, in three references, most precise being 100 ms 1 by 2004Gr20, but this value is in disagreement with the values of 125.5 ms 25 and 119 ms 6 by 2022Tr03, and 123 ms 10 by 1995So03. We adopted the unweighted average of this discrepant dataset. Another outstanding issue is that of the β+-delayed proton decay of 44Cr g.s. to 44V, where the T=2, 0+ IAS state in 44V is expected to be strongly populated by a superallowed β transition, but has not been definitely identified as discussed in detail by 2020Fu05. A detailed study of 44Cr decay is required to unravel the status of the T=2, 0+ IAS state in 44V. This work supersedes earlier ENSDF evaluations of A=44 by 2011Ch39 and 1999Ca45.