Sheltered beneath practically a mile of rock in Abruzzo, Italy, scientists are laborious at work unraveling the secrets and techniques of the universe’s smallest bits of matter. When a radioactive course of referred to as beta decay happens, it sometimes emits two particles: a negatively charged electron and a model of a tiny, neutrally charged neutrino. The Massive Enriched Germanium Experiment for Neutrinoless Double Beta Decay (LEGEND-200) on the Gran Sasso Nationwide Laboratory is designed to determine whether or not this course of can happen with out leading to a neutrino on the finish. The reply may form our understanding of how matter got here to be.
The method of “neutrinoless double beta decay,” if it does happen, occurs very not often. Noticing when decay leads to electrons however not neutrinos might be tough, particularly as a result of neutrinos are plentiful all over the place—billions go by way of your physique each second—and are sometimes produced when background radiation reacts with machine parts.
That is why scientists deal with “selecting actually low-radioactivity supplies to start out with after which additionally developing with a number of intelligent methods to reject background [particles],” says Drexel College particle physicist Michelle Dolinski, who will not be concerned within the challenge.
LEGEND-200 is provided with barely radioactive germanium crystals, which act as each a supply of beta decay and a neutrino detector. To display screen out ambient particles, all the setup is immersed in a cryogenic tank shielded by water and liquid argon. That core is surrounded with inexperienced optical fibers and a reflective movie that bounces away stray particles.
If LEGEND-200 observes neutrinoless double beta decay, it would imply that not like protons, electrons and different elementary particles—which every have an “antiparticle” that destroys them on contact—neutrinos are their very own antiparticles and may destroy each other. If so, then when double beta decay happens, two neutrinos can be produced and instantly annihilated, leaving none behind. “This is a crucial ingredient in attempting to grasp why matter dominated over antimatter within the early universe and why the universe exists because it does at the moment,” Dolinski says.
LEGEND collaborator Laura Baudis, who’s an experimental physicist on the College of Zurich, is happy to see what this experiment uncovers when it begins amassing information later this 12 months. “There are such a lot of issues we do not find out about neutrinos,” she says. “They’re actually nonetheless stuffed with surprises.”