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A new upper limit on the mass of neutrino

Submitted by Shane D Debolt on February 23, 2022 - 11:30am
Katrin Spectrometer
Katrin Spectrometer

UW News has published a story about new findings in the quest to determine the mass of the neutrino, the lightest known subatomic particle. In a paper published Feb. 14 in Nature Physics, the Karlsruhe Tritium Neutrino Experiment — or KATRIN — reported that the neutrino’s mass is below 0.8 electron volts. Honing in on the elusive value of the neutrino’s mass will solve a major outstanding mystery in particle physics and equip scientists with a more complete view of the fundamental forces and particles that shape ourselves, our planet and the cosmos.

The UW is a founding member of KATRIN. Under the direction of Dr. Hamish Robertson, a UW professor emeritus of physics, the UW was the lead U.S. institution for designing and acquiring KATRIN’s electron detection system. The collaboration has been hunting for the neutrino’s mass since the experiment began collecting data in 2018. The team’s first reported measurement in 2019 cut the upper limit for this value almost in half, from 2 electron volts to about 1.1. With the new findings reported this month, the upper limit drops below 1 electron volts for the first time.

In addition to Dr. Robertson, UW co-authors on the paper are Dr. Peter Doe, a research professor of physics; Dr. Sanshiro Enomoto, a research associate professor of physics; and Dr. Menglei Sun, a former postdoctoral researcher in the UW Center for Experimental Nuclear Physics and Astrophysics.

Here is a link to the full story: