The rest mass of an electron is about 511 keV; the sum of the masses of the three flavors of neutrinos is probably ≤ 1 eV.
This much was known already from calculations: https://www.natureworldnews.com/articles/5968/20140210/mass-neutrinos-accurately-calculated-first-time-physicists-report.htm
The recent results appear to confirm it experimentally, though the upper bound given here is still larger than that calculated: https://arxiv.org/pdf/1909.06048.pdf
We report on the neutrino mass measurement result from the first four-week science run of theKarlsruhe Tritium Neutrino experiment KATRIN in spring 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are energy analyzed by a high-resolution MAC-E filter. Afit of the integrated electron spectrum over a narrow interval around the kinematic endpoint at 18.57keV gives an effective neutrino mass square value of (−1.0+ 0.9−1.1) eV2. From this we derive an upperlimit of 1.1 eV (90% confidence level) on the absolute mass scale of neutrinos. This value coincideswith the KATRIN sensitivity. It improves upon previous mass limits from kinematic measurementsby almost a factor of two and provides model-independent input to cosmological studies of structureformation.
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