From Quanta magazine: What Could Explain the Gallium Anomaly? by Jonathan O'Callaghan
Physicists have ruled out a mundane explanation for the strange findings of an old Soviet experiment, leaving open the possibility that the results point to a new fundamental particle.
The experimental apparatus used in the SAGE and BEST experiments at the Baksan Neutrino Observatory./Konstantin Malanchev
Deep in the Caucasus Mountains, on the border between Russia and Georgia, an unusual experiment is taking place. In an underground lab shielded by a mountain of rock, highly radioactive material sits inside a vat of liquid gallium, blasting out particles called neutrinos that break the gallium down into atoms of germanium.
The goal is to resolve a little-known mystery of physics: the gallium
anomaly. “I think it’s one of the most compelling anomalies in neutrino
physics that we have today,” said
Ben Jones,
a neutrino physicist at the University of Texas, Arlington. Some three
decades ago, in a previous version of the current experiment, scientists
first detected a dearth of the expected germanium atoms that still
can’t be explained...
