arXiv:1108.5312·v2·Nuclear Experiment
Experimental Validation of the Largest Calculated Isospin-Symmetry-Breaking Effect in a Superallowed Fermi Decay
D. Melconian🇺🇸 · S. Triambak🇺🇸 · C. Bordeanu🇺🇸 · A. García🇺🇸 · J. C. Hardy🇺🇸 · V. E. Iacob🇺🇸 · N. Nica🇺🇸 · H. I. Park🇺🇸 · G. Tabacaru🇺🇸 · L. Trache🇺🇸 · I. S. Towner🇺🇸 · R. E. Tribble🇺🇸 · Y. Zhai🇺🇸
Abstract
A precision measurement of the gamma yields following the beta decay of 32Cl has determined its isobaric analogue branch to be (22.47^{+0.21}_{-0.19})%. Since it is an almost pure Fermi decay, we can also determine the amount of isospin-symmetry breaking in this superallowed transition. We find a very large value, delta_C=5.3(9)%, in agreement with a shell-model calculation. This result sets a benchmark for isospin-symmetry-breaking calculations and lends support for similarly-calculated, yet smaller, corrections that are currently applied to 0+ -> 0+ transitions for tests of the Standard Model.