Physics Letters B (Apr 2017)

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

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

DOI
https://doi.org/10.1016/j.physletb.2017.01.039
Journal volume & issue
Vol. 767, no. C
pp. 20 – 24

Abstract

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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(Cr46)=7604(11) keV, QEC(Fe50)=8150(6) keV and QEC(Ni54)=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(Fe50)=3103(70) s and Ft(Ni54)=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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