Testing Lorentz invariance in β decay

Auke Sytema

Research output: ThesisThesis fully internal (DIV)

650 Downloads (Pure)


In this thesis we investigate violation of Lorentz invariance in the weak interaction, specifically in β decay. For this purpose an experiment is performed with nuclear-spin-polarized 20Na that decays by emitting a β particle. Lorentz invariance is the property that the laws of nature do not depend on the orientation or the velocity of the frame of reference. In this specific case the lifetime should not depend on the orientation of the nuclear spin.

Lorentz invariance is at the basis of the two most successful theories of nature: general relativity, that describes gravity, and the Standard model of particle physics. Reasons to test Lorentz invariance are the essential role of Lorentz invariance in modern physics, the connection between Lorentz invariance and CPT symmetry, and the possibility of violation of Lorentz invariance in theories of quantum gravity. Lorentz invariance is very well tested for general relativity and electromagnetism, however there are relatively few tests of Lorentz invariance in the weak interaction.

The setup of the experiment is described. The 20Na is stopped in a buffer gas, and polarized by optical pumping with a solid-state laser. This experiment sets limits on violation of Lorentz invariance in β decay.

The results of the experiment are interpreted in the formalisms of the chi tensor and the Standard-Model Extension. Experiments that can further improve limits on Lorentz invariance in β decay are described. Two recommendations are a measurement of γ anisotropy of a nonpolarized β emitter and a measurement of β decay at high energy.
Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • University of Groningen
  • Wilschut, Hans, Supervisor
  • Onderwater, Cornelis, Co-supervisor
Award date5-Dec-2016
Place of Publication[Groningen]
Print ISBNs978-90-367-9319-3
Electronic ISBNs978-90-367-9318-6
Publication statusPublished - 2016

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