Researchers at the Cryogenic Underground Observatory for Rare Events (CUORE) announced this week that they had placed some of the most stringent limits yet on the strange possibility that the neutrino is its own antiparticle. CUORE has spent the last three years patiently waiting to see evidence of a distinctive nuclear decay process, only possible if neutrinos and antineutrinos are the same particle. Their new data shows that this decay doesn’t happen for trillions of trillions of years, if it happens at all.
An international research team that includes Lawrence Berkeley National Laboratory (Berkeley Lab) scientists has established a new upper limit of 0.8 electron volts (eV) for the mass of the neutrino, a milestone that will bear on future discoveries in nuclear and particle physics, and cosmology.
The Daya Bay Reactor Neutrino Experiment collaboration – which made a precise measurement of an important neutrino property eight years ago, setting the stage for a new round of experiments and discoveries about these hard-to-study particles – has finished taking data. Though the experiment is formally shutting down, the collaboration will continue to analyze its complete dataset to improve upon the precision of findings based on earlier measurements.
Berkeley Lab has a long history of participating in neutrino experiments and discoveries in locations ranging from a site 1.3 miles deep at a nickel mine in Ontario, Canada, to an underground research site near a nuclear power complex northeast of Hong Kong, and a neutrino observatory buried in ice near the South Pole.
Surrounded by lead and also shielded by nearly a mile of rock from the natural bombardment of particles at the Earth’s surface, the CUORE experiment has amassed the largest dataset yet for a project of its kind, which is using solid crystals to detect a theorized event that would answer a big question about how matter won out over antimatter in our universe.
An international group of more than 260 scientists has produced one of the most stringent tests to date for the existence of sterile neutrinos, which are theorized particles related to the three known types, or “flavors,” of neutrinos but that are not directly detectable.
Berkeley Lab-affiliated researchers played a leading role in analyzing data for a demonstration experiment in France that has achieved record precision for a specialized detector material.
Largely unaffected by the pandemic, the Daya Bay reactor neutrino experiment in Shenzen, China, has continued to pump data to remote supercomputers for analyses.
As the COVID-19 outbreak took hold in Italy, researchers working on a nuclear physics experiment called CUORE at an underground laboratory in central Italy scrambled to keep the ultrasensitive experiment running and launch new tools and rules for remote operations.
An international team of scientists that includes Berkeley Lab researchers has announced a breakthrough in its quest to measure the mass of the neutrino, one of the most abundant yet elusive elementary particles in our universe.