Search for new light bosons with the KATRIN experiment

The Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to measure the effective electron antineutrino mass with a sensitivity better than mνc2=0.3 eV (90% C.L.) in a kinematic approach by applying precision electron spectroscopy to the beta decay of molecular tritium. This determination occurs in the spectral endpoint (E0) region, i.e. up to some tens of eV below E0≈ 18.6 keV.

Light neutral pseudoscalars and vector bosons arise in many theories beyond the Standard Model (BSM). Constraints on the couplings of such particles to neutrinos or electrons can be derived from cosmological, astrophysical and laboratory observations. High-statistics beta spectroscopy with KATRIN is a complementary probe for these new physics theories; with light bosons emitted in tritium beta decay, the spectrum is altered as described in JHEP 01 (2019) 206. This talk introduces possible interactions of light BSM bosons with their imprint on the observed electron spectrum. We estimate the sensitivity of the second KATRIN measurement campaign to the light boson couplings.

This work is supported by the Helmholtz Association and by the Ministry for Education and Research BMBF (grant numbers 05A23PMA, 05A23PX2, 05A23VK2 and 05A23WO6).