News Particle Physics Neutrinos’ maximum possible mass shrinks further The KATRIN experiment nearly halved the maximum possible mass for the subatomic particles The KATRIN experiment (pictured) measures the energies of electrons produced in radioactive decays of tritium to determine the mass of neutrinos. Markus Breig/KIT By Emily Conover 16 minutes ago Neutrinos are known to have tiny masses. A new result proclaims the subatomic particles to be even tinier still. The electrically neutral particles, produced in radioactive decays and in reactions in the sun and elsewhere in the cosmos, have a mass of less than 0.45 electron volts, physicists report in the April 11 Science. The result, from the Karlsruhe Tritium Neutrino, or KATRIN, experiment slashes the experiment’s previous upper limit for neutrino mass by nearly half. Sign up for our newsletter We summarize the week's science breakthroughs every Thursday.