Neutrino Experiment Could Reveal Why Any Matter Exists
In a new experiment from Fermilab that began yesterday, weakly interacting particles called neutrinos will be blasted 500 miles in order to determine why matter exists in the universe.
Every particle of matter has a corresponding particle of antimatter, or antiparticle. When a particle and its antiparticle meet, they are both immediately annihilated. As a result, there must be more matter than antimatter in the universe, because otherwise all particles would be annihilated and complex bodies would never form. So in a sense, the mechanism behind the asymmetry between matter and antimatter is the reason we exist, essentially the reason anything exists.
Neutrinos are particles that have no electric charge and interact very weakly with matter. Because they are neutral, they are not affected by electromagnetic forces, but are only affected by the weak subatomic force. They interact so little with matter, in fact, that they're one of the top candidates for dark matter (or at least part of it). The researchers at Fermilab hypothesize that there is a fundamental difference between the behavior of neutrinos and antineutrinos, a difference that might be shared by other particle-antiparticle pairs. This behavioral difference may explain why the observable universe is made out of matter rather than antimatter.
The experiment, which is expected to last six years, will see the researchers create a potent neutrino beam that will bombard detectors with billions of neutrinos per second. Since the particles so rarely interact with matter, it is likely that only a few neutrinos will be detected per day, if that. When the experiment began, it was unclear whether they would be able to detect the neutrinos for study at all, but after only one day, they claim that they have observed neutrinos interacting with matter.
"Scientists believe that a better understanding of neutrinos, one of the most abundant and difficult-to-study particles, may lead to a clearer picture of the origins of matter and the inner workings of the universe," Fermilab wrote in a press release. "Using the world's most powerful beam of neutrinos... the experiment can precisely record the telltale traces of those rare instances when one of these ghostly particles interacts with matter."