Q_EC values of the Superallowed beta Emitters 50Mn and 54Co

Abstract

Using a new fast cleaning procedure to prepare isomerically pure ion samples, we have measured the beta-decay Q_EC values of the superallowed beta-emitters 50Mn and 54Co to be 7634.48(7) keV and 8244.54(10) keV, respectively, results which differ significantly from the previously accepted values. The corrected Ft values derived from our results strongly support new isospin-symmetry-breaking corrections that lead to a higher value of the up-down quark mixing element, Vud, and improved confirmation of the unitarity of the Cabibbo-Kobayashi-Maskawa matrix.

4 pages, 5 figures, 1 table, submitted to Phys. Rev. Lett

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• An improved calculation of the isospin-symmetry-breaking corrections to superallowed Fermi beta decay
• The Ramsey method in high-precision mass spectrometry with Penning traps: Experimental results
• Q value of the 100Mo Double-Beta Decay
• Q-values of the Superallowed beta-Emitters 26m-Al, 42-Sc and 46-V and their impact on V_ud and the Unitarity of the CKM Matrix

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