Magneto-ν: Heavy neutral lepton search using 241Pu β− decays
The MAGNETO-ν experiment utilized a high-statistics measurement of 241Pu β− decays with metallic magnetic calorimeters to find no evidence for keV-scale heavy neutral leptons, thereby establishing an upper limit of ∣Ue4∣2<1.31×10−3 at 95% confidence for an 11.5-keV HNL mixing with the electron neutrino.
C. Lee, X. Zhang, A. Kavner, T. Parsons-Davis, D. Lee, N. Hines, S. T. P. Boyd, M. Loidl, X. Mougeot, M. Rodrigues, M. K. Lee, J. Song, R. Wood, I. Jovanovic, G. B. Kim2026-03-05🔬 physics