Phys. Rev. Lett. 95, 102501 (2005) [4 pages]Q Value of the Superallowed Decay of 46V and Its Influence on Vud and the Unitarity of the Cabibbo-Kobayashi-Maskawa MatrixReceived 15 April 2005; published 29 August 2005 The masses of the radioactive nuclei 46V and its decay daughter 46Ti have been measured with the Canadian Penning Trap on-line Penning trap mass spectrometer to a precision of 1×10-8. A QEC value of 7052.90(40) keV for the superallowed beta decay of 46V is obtained from the difference of these two masses. With this precise Q value, the Ft value for this decay is determined with improved precision. An investigation of an earlier Q-value measurement for 46V uncovers a set of 7 measurements that cannot be reconciled with modern data and affects previous evaluations of Vud from superallowed Fermi decays. A new evaluation, adding our new data and removing the discredited subset, yields new values for GV and Vud. When combined with recent results for Vus, this yields modified constraints for the unitarity of the Cabibbo-Kobayashi-Maskawa matrix and other extensions of the standard model. URL:
http://link.aps.org/doi/10.1103/PhysRevLett.95.102501
DOI:
10.1103/PhysRevLett.95.102501
PACS:
21.10.Dr, 23.40.Bw, 23.40.Hc, 27.40.+z
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