Precision measurements of the ${}^{60}$Co $\beta$-asymmetry parameter in search for tensor currents in weak interactions

Abstract

The $\beta$-asymmetry parameter $\tilde{A}$ for the Gamow-Teller decay of ${}^{60}$Co was measured by polarizing the radioactive nuclei with the brute force low-temperature nuclear-orientation method. The ${}^{60}$Co activity was cooled down to milliKelvin temperatures in a ${}^3$He-${}^4$He dilution refrigerator in an external 13 T magnetic field. The $\beta$ particles were observed by a 500 $\mu m$ thick Si PIN diode operating at a temperature of about 10 K in a magnetic field of 0.6 T. Extensive GEANT4 Monte-Carlo simulations were performed to gain control over the systematic effects. Our result, $\tilde{A}=-1.014(12{)}_{stat}(16{)}_{syst}$, is in agreement with the Standard-Model value of $-0.987(9)$, which includes recoil-order corrections that were addressed for the first time for this isotope. Further, it enables limits to be placed on possible tensor-type charged weak currents as well as other physics beyond the Standard Model.

References in corpus (11)

• Superallowed 0+ to 0+ nuclear beta decays: A new survey with precision tests of the conserved vector current hypothesis and the standard model
• Tests of the standard electroweak model in beta decay
• Ft values of the T = 1/2 mirror beta transitions
• Measurement of the Beta-Neutrino Correlation of Sodium-21 using Shakeoff Electrons
• Measurement of the Neutrino Asymmetry Parameter B in Neutron Decay
• Measurement of the Transverse Polarization of Electrons Emitted in Free Neutron Decay
• Supersymmetric Contributions to Weak Decay Correlation Coefficients
• First Measurement of the Neutron $\beta$-Asymmetry with Ultracold Neutrons
• Tensor interaction constraints from beta decay recoil spin asymmetry of trapped atoms
• The WITCH experiment: Acquiring the first recoil ion spectrum
• Performance of silicon PIN photodiodes at low temperatures and in high magnetic fields

Cited by in corpus (1)

• Measurement of the $\beta$-asymmetry parameter of ${}^{67}$Cu in search for tensor type currents in the weak interaction