Search for Lorentz-Invariance Violation with the first KATRIN data

TL;DR

This paper uses initial KATRIN data to set new limits on Lorentz-invariance violation parameters in the neutrino sector, providing constraints where previous experiments could not.

Contribution

First experimental constraints on specific Lorentz-violation parameters using beta decay spectral data from KATRIN.

Findings

Set the first limit on |(a_{of}^{(3)})_{11}| < 3.7×10^{-6} GeV

Derived new constraints on (a_{of}^{(3)})_{00} and (a_{of}^{(3)})_{10}

Demonstrated KATRIN's capability to probe Lorentz-invariance violations

Abstract

Some extensions of the Standard Model of Particle Physics allow for Lorentz invariance and Charge-Parity-Time (CPT)-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 $(a_{\text{of}}^{(3)})_{00}$, $(a_{\text{of}}^{(3)})_{10}$ and $(a_{\text{of}}^{(3)})_{11}$ which would manifest themselves in a non-isotropic beta-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 limit on $\left|(a_{\text{of}}^{(3)})_{11}\right|$ of $< 3.7\cdot10^{-6}$ GeV at 90\% confidence level. Moreover, we derive new constraints on $(a_{\text{of}}^{(3)})_{00}$ and $(a_{\text{of}}^{(3)})_{10}$.