Journal Article High-precision QEC values of superallowed 0+ → 0+β-emitters 46Cr, 50Fe and 54Ni

Zhang, P.  ,  Xu, X.  ,  Shuai, P.  ,  Chen, R.J.  ,  Yan, X.L.  ,  Zhang, Y.H.  ,  Wang, M.  ,  Litvinov, Yu.A.  ,  Blaum, K.  ,  Xu, H.S.  ,  Bao, T.  ,  Chen, X.C.  ,  Chen, H.  ,  Fu, C.Y.  ,  He, J.J.  ,  Kubono, S.  ,  Lam, Y.H.  ,  Liu, D.W.  ,  Mao, R.S.  ,  Ma, X.W.  ,  Sun, M.Z.  ,  Tu, X.L.  ,  Xing, Y.M.  ,  Yang, J.C.  ,  Yuan, Y.J.  ,  Zeng, Q.  ,  Zhou, X.  ,  Zhou, X.H.  ,  Zhan, W.L.  ,  Litvinov, S.  ,  Audi, G.  ,  Uesaka, T.  ,  Yamaguchi, Y.  ,  Yamaguchi, T.  ,  Ozawa, A.  ,  Sun, B.H.  ,  Sun, Y.  ,  Xu, F.R.

767pp.20 - 24 , 2017-04 , Elsevier B.V.
Short-lived 46Cr, 50Fe and 54Ni were studied by isochronous mass spectrometry at the HIRFL-CSR facility in Lanzhou. The measured precision mass excesses (ME) of 46Cr, 50Fe and 54Ni are −29471(11) keV, −34477(6) keV and −39278(4) keV, respectively. The superallowed 0+→0+β-decay Q values were derived to be QEC(46Cr) = 7604(11) keV, QEC(50Fe) = 8150(6) keV and QEC(54Ni) = 8731(4) keV. The values for 50Fe and 54Ni are by one order of magnitude more precise than the adopted literature values. By combining the existing half-lives and branching ratios, we obtained the corrected Ft values to be Ft(50Fe) = 3103(70)s and Ft(54Ni) = 3076(50)s. The main contribution to the Ft uncertainties is now due to β-decay branching ratios, still, more high-precision measurements of the half-lives, the masses, and especially the branching ratios are needed in order to satisfy the requirements for a stringent CVC test.

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