β decay of 32Cl: Precision γ-ray spectroscopy and a measurement of isospin-symmetry breaking Academic Article uri icon

abstract

  • Background: Models to calculate small isospin-symmetry-breaking effects in superallowed Fermi decays have been placed under scrutiny in recent years. A stringent test of these models is to measure transitions for which the correction is predicted to be large. The decay of 32Cl decay provides such a test case.Purpose: The purpose of this paper is to improve the γ yields following the β decay of 32Cl and to determine the ft values of the the β branches, particularly the one to the isobaric-analog state in 32S.Method: Reaction-produced and recoil-spectrometer-separated 32Cl is collected in a tape and transported to a counting location where β-γ coincidences are measured with a precisely calibrated high-purity germanium detector.Results: The precision on the γ yields for most of the known β branches has been improved by about an order of magnitude, and many new transitions have been observed. We have determined 32Cl-decay transition strengths extending up to E x ∼11 MeV. The ft value for the decay to the isobaric-analog state in 32S has been measured. A comparison to a shell-model calculation shows good agreement.Conclusions: We have experimentally determined the isospin-symmetry-breaking correction to the superallowed transition of this decay to be (δ C -δ NS )exp=5. 4(9)%, significantly larger than for any other known superallowed Fermi transition. This correction agrees with a shell-model calculation, which yields δ C -δ NS =4.8(5)%. Our results also provide a way to improve the measured ft values for the β decay of 32Ar. © 2012 American Physical Society.

altmetric score

  • 0.5

author list (cited authors)

  • Melconian, D., Triambak, S., Bordeanu, C., García, A., Hardy, J. C., Iacob, V. E., ... Zhai, Y.

citation count

  • 11

publication date

  • February 2012