Abstract
Some extensions of the Standard Model of particle physics allow for Lorentz invariance and charge-parity-time invariance violations. In the neutrino sector strong constraints have been set by neutrino-oscillation and time-of-flight experiments. However, some Lorentz-invariance-violating parameters are not accessible via these probes. In this work, we focus on the parameters , , and which would manifest themselves in a nonisotropic -decaying source as a sidereal oscillation and an overall shift of the spectral endpoint. Based on the data of the first scientific run of the KATRIN experiment, we set the first 90% confidence-level limit on of to , depending on the phase. Moreover, we derive new constraints on and .
- Received 2 October 2022
- Revised 8 February 2023
- Accepted 14 March 2023
DOI:https://doi.org/10.1103/PhysRevD.107.082005
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