Positron-neutrino correlations in 32Ar and 33Ar Decays: Probes of Scalar weak currents and nuclear isospin mixing
A. Garcia, E. G. Adelberger, C. Ortiz, H. E. Swanson, M. Beck, O. Tengblad, M. J. G. Borge, I. Martel, H. Bichsel, the Isolde Collaboration
Abstract
The positron-neutrino correlation in the 0+ 0+ βdecay of 32Ar was measured at ISOLDE by analyzing the effect of lepton recoil on the shape of the narrow proton group following the superallowed decay. Our result is consistent with the Standard Model prediction; for vanishing Fierz interference we find a=0.9989 0.0052 0.0036. Our result leads to improved constraints on scalar weak interactions. The positron-neutrino correlation in 33Ar decay was measured in the same experiment; for vanishing Fierz interference we find a=0.944 0.002 0.003. The 32Ar and 33Ar correlations, in combination with precision measurements of the half-lives, superallowed branching ratios and beta endpoint energies, will determine the isospin impurities of the superallowed transitions. These will provide useful tests of isospin-violation corrections used in deducing |V ud| which currently indicates non-unitarity of the KM matrix.
Create a lesson
Related papers
Direct measurement of the in-medium η mass spectrum through the γγ decay channel
Y. Matsumura, N. Muramatsu, T. A. Hashimoto et al.
STAR Highlights II: Study of Small Systems and the Search for New, Exotic Physics
Jiangyong Jia
Cluster emission and its impact on the r-process nucleosynthesis
Natalia Thomas, Silvia Bara, Thomas Elias Cocolios et al.
Core Breaking at Low Spin in 68Zn from Nuclear Resonance Fluorescence
S. R. Johnson, R. V. F. Janssens, B. A. Brown et al.
Isoscalar Giant Resonances in the even-A Pd Isotopes
J. Arroyo, U. Garg, T. Furuno et al.
Efficient production of 229m,gTh via neutron capture in VUV-transparent crystals
Zhong-yi Chen, Hao-yang Lan, Di Wu et al.