Year: 2015
Type: article
Abstract: An unexpected breakdown of the isobaric multiplet mass equation in the $A=20,T=2$ quintet was recently reported, presenting a challenge to modern theories of nuclear structure. In the present work, the excitation energy of the lowest $T=2$ state in $^{20}\mathrm{Na}$ has been measured to be $6498.4\ifmmode\pm\else\textpm\fi{}0.{2}_{\text{stat}}\ifmmode\pm\else\textpm\fi{}0.{4}_{\text{syst}}$ keV by using the superallowed ${0}^{+}\ensuremath{\rightarrow}{0}^{+}$ beta decay of $^{20}\mathrm{Mg}$ to access it and an array of high-purity germanium detectors to detect its $\ensuremath{\gamma}$-ray deexcitation. This value differs by 27 keV (1.9 standard deviations) from the recommended value of $6525\ifmmode\pm\else\textpm\fi{}14$ keV and is a factor of 28 more precise. The isobaric multiplet mass equation is shown to be revalidated when the new value is adopted.
Source: Physical Review C
Authors: B. E. Glassman, D. Pérez-Loureiro, C. Wrede, J. Allen, D. W. Bardayan, M. B. Bennett, B. A. Brown, K. A. Chipps, M. Febbraro, C. Fry, M. R. Hall, O. Hall, S. N. Liddick, P. O'Malley, W. Ong, S. D. Pain, S. B. Schwartz, P. Shidling, H. Sims, P. Thompson, H. Zhang
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: National Science Foundation
OpenAlex ID: W2096536742