TY - JOUR

T1 - High-precision branching ratio measurement and spin assignment implications for Ga-62 superallowed beta decay

AU - MacLean, A. D.

AU - Laffoley, A. T.

AU - Svensson, C. E.

AU - Ball, G. C.

AU - Leslie, J. R.

AU - Andreoiu, C.

AU - Babu, A.

AU - Bhattacharjee, S.S.

AU - Bidaman, H.

AU - Bildstein, V.

AU - Burbadge, C.

AU - Bowry, M.

AU - Cheng, C.

AU - Cross, D. S.

AU - Diaz-Varela, A.

AU - Dillmann, I.

AU - Dunlop, M. R.

AU - Dunlop, R.

AU - Evitts, L. J.

AU - Finlay, P.

AU - Gillespie, S.

AU - Garnsworthy, A. B.

AU - Garrett, P. E.

AU - Gopaul, E.

AU - Grinyer, G. F.

AU - Hackman, G.

AU - Jigmeddorj, B.

AU - Leach, K. G.

AU - Kassanda, E.

AU - McAfee, J.

AU - Moukaddam, M.

AU - Natzke, C.

AU - Nittala, S.

AU - Olaizola, B.

AU - Park, J.

AU - Paxman, C.

AU - Pore, J. L.

AU - Porzio, C.

AU - Radich, A. J.

AU - Ruotsalainen, P.

AU - Saito, Y.

AU - Sharma, S.

AU - Smallcombe, J.

AU - Sultana, R.

AU - Turko, J.

AU - Yates, D.

AU - Zidar, T.

PY - 2020/11/19

Y1 - 2020/11/19

N2 - A high-precision branching ratio measurement for the superallowed Fermi β+ emitter 62Ga wasperformed with the Gamma-Ray Infrastructure for Fundamental Investigations of Nuclei (GRIFFIN)spectrometer at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility atTRIUMF. The high efficiency of the GRIFFIN spectrometer allowed 63 γ-ray transitions, withintensities down to ≈1 part per million (ppm) per 62Ga β+ decay, to be placed in the level schemeof the daughter nucleus 62Zn, establishing the superallowed β branching ratio for 62Ga decay to be99.8577+0.0023−0.0029%, a factor of 4 more precise than the previous world average. For several cascades,γ−γ angular correlation measurements were performed to assign spins and/or determine the mixingratios of transitions. In particular, the spin of the 2.342 MeV excited state in the daughter nucleus62Zn was definitively assigned as J = 0. This assignment resolves a discrepancy between previousmeasurements and has important implications for the isospin symmetry breaking correction, δC1,in 62Ga superallowed Fermi β decay.Keywords: 62Ga, β decay, branching ratios, γ − γ angular correlations, HPGe, isospin symmetry breaking

AB - A high-precision branching ratio measurement for the superallowed Fermi β+ emitter 62Ga wasperformed with the Gamma-Ray Infrastructure for Fundamental Investigations of Nuclei (GRIFFIN)spectrometer at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility atTRIUMF. The high efficiency of the GRIFFIN spectrometer allowed 63 γ-ray transitions, withintensities down to ≈1 part per million (ppm) per 62Ga β+ decay, to be placed in the level schemeof the daughter nucleus 62Zn, establishing the superallowed β branching ratio for 62Ga decay to be99.8577+0.0023−0.0029%, a factor of 4 more precise than the previous world average. For several cascades,γ−γ angular correlation measurements were performed to assign spins and/or determine the mixingratios of transitions. In particular, the spin of the 2.342 MeV excited state in the daughter nucleus62Zn was definitively assigned as J = 0. This assignment resolves a discrepancy between previousmeasurements and has important implications for the isospin symmetry breaking correction, δC1,in 62Ga superallowed Fermi β decay.Keywords: 62Ga, β decay, branching ratios, γ − γ angular correlations, HPGe, isospin symmetry breaking

U2 - 10.1103/PhysRevC.102.054325

DO - 10.1103/PhysRevC.102.054325

M3 - Article

VL - 102

JO - Physical Review C

JF - Physical Review C

SN - 2469-9985

IS - 5

M1 - 054325

ER -