Searching for 0(+) states in Cr-50: Implications for the superallowed beta decay of Mn-50

Leach, K. G.; Garrett, P. E.; Ball, G. C.; Bender, P. C.; Bildstein, V.; Brown, B. A.; Burbadge, C.; Faestermann, T.; Hadinia, B.; Holt, J. D.; Laffoley, A. T.; Jamieson, D. S.; Jigmeddorj, B.; Radich, A. J.; Rand, E. T.; Stroberg, S. R.; Svensson, C. E.; Towner, I. S. and Wirth, H.-F. (2016): Searching for 0(+) states in Cr-50: Implications for the superallowed beta decay of Mn-50. In: Physical Review C, Vol. 94, No. 1, 11304

Abstract

A Cr-52(p, t)Cr-50 two-neutron pickup reaction was performed using the Q3D magnetic spectrograph at the Maier-Leibnitz-Laboratorium in Garching, Germany. Excited states in Cr-50 were observed up to an excitation energy of 5.3 MeV. Despite significantly increased sensitivity and resolution over previous work, no evidence of the previously assigned first excited 0(+) state was found. As a result, the 0(2)(+) state is reassigned at an excitation energy of E-x = 3895.0(5) keV in Cr-50. This reassignment directly impacts direct searches for a nonanalog Fermi beta(+) decay branch in Mn-50. These results also show better systematic agreement with the theoretical predictions for the 0(+) state spectrum in Cr-50 using the same formalism as the isospin-symmetry-breaking correction calculations for superallowed nuclei. The experimental data are also compared to ab-initio shell-model predictions using the IM-SRG formalism based on NN and 3N forces from chiral-EFT in the pf-shell for the first time.

• Item Type: Journal article
• Faculties: Physics
• Subjects: 500 Science > 530 Physics
• ISSN: 2469-9985
• Language: English