Light sterile neutrino search in the eV—keV range with the KATRIN experiment

by Weiran Xu (MIT)

Tuesday 9 Sept 2025, 15:30 → 17:30 US/Eastern

Abstract: 

Neutrinos are the lightest and most abundant elementary particles in the universe. While the Standard Model predicts only three neutrino flavors, discrepancies such as the solar neutrino deficit in gallium radioactive-source experiments, reactor antineutrino anomalies, and low-energy excesses in short-baseline accelerator experiments have motivated the hypothesis of a fourth neutrino state, called a sterile neutrino, which does not participate in the weak interaction. The KATRIN experiment, employing a MAC-E-filter type spectrometer, performs precise spectroscopy of tritium $\beta$ decay near its kinematic endpoint. A sterile neutrino state in this domain would manifest as a spectral distortion superimposed on the active branch of the decay. Based on data from the first five measurement campaigns, significant portions of the eV-scale sterile neutrino parameter space have been constrained, which were previously suggested by the gallium anomaly and the Neutrino-4 experimental search. After the neutrino mass measurement phase ending in 2025, KATRIN will transition to its TRISTAN phase and probe the keV parameter space for sterile neutrinos, aiming at a sensitivity to the active-sterile mixing of $sin^2(\theta) \sim 10^{-6}$. This talk will focus on the experimental setup of the KATRIN experiment, present its results on neutrino mass measurements and sterile neutrino searches from 259 days of data, and discuss the upcoming detector upgrade for keV-scale sterile neutrino searches.

Zoom:https://bnl.zoomgov.com/j/1617489674?pwd=aTmhSZ1ncKD7wWlqQ2iHfoTniiAlOX.1

 

Meeting ID: 161 748 9674

Passcode: 

893268