Q value of the superallowed decay of Mg 22 and the calibration of the Na 21 (p,γ) experiment Academic Article uri icon


  • The masses of the radioactive nuclei 22 Mg and 22 Na have been measured with the Canadian Penning trap on-line mass spectrometer to a precision of 3 × 10 -8 and 1 × 10 -8 , respectively. A Q EC value of 4124.39(73) keV for the superallowed β decay of 22 Mg 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 and is found to be consistent with the existing precision data set of superallowed Fermi emitters. This provides an important test of the isospin symmetry-breaking corrections. If the mass of 22 Mg determined here is used in the calibration of a recent 21 Na(p, γ) 22 Mg measurement, part of the discrepancy observed in that measurement is removed.

author list (cited authors)

  • Savard, G., Clark, J. A., Buchinger, F., Crawford, J. E., Gulick, S., Hardy, J. C., ... Zhou, Z.

citation count

  • 34

publication date

  • October 2004