Speaker
Description
Precision measurements of the tritium β-decay spectrum provide a powerful and model-independent probe of physics beyond the Standard Model. In particular, keV-scale sterile neutrinos are well-motivated warm dark matter candidates that would induce a characteristic kink-like distortion in the β spectrum. Furthermore, generalized neutrino interactions (GNIs) within a dimension-6 effective field theory framework can modify the spectral shape across a broad energy range via additional scalar, vector, and tensor couplings.
The LiFE-SNS project performs a calorimetric measurement of the full tritium β-decay spectrum using neutron-irradiated LiF crystals with embedded tritium, read out by a cryogenic metallic magnetic calorimeter (MMC) operated at millikelvin temperatures. This approach provides high energy resolution and high detection efficiency across the entire β-energy range, enabling sensitivity to both localized and global spectral distortions. In this work we report new constraints on sterile neutrinos in the 10 keV mass range from the first 10-day dataset of the Phase-I operation.
The measured spectrum is compared with a detailed theoretical model that incorporates detector response and analysis effects. Spectral fits are performed to search for the characteristic signatures induced by keV-scale sterile neutrinos as well as spectral distortions predicted by GNIs. These first results demonstrate the feasibility and performance of the LiFE-SNS experimental approach and establish the analysis framework for the full Phase-I dataset and future higher-statistics measurements.
| Main Contribution topic | Instrumentation for Dark Matter searches |
|---|---|
| Secondary contribution topic | Axion / Sterile |