It's a breakthrough that could have a significant impact on physics and the universe as we understand it. The team, working at the Daya Bay reactor facility in China, discovered the third and final known neutrino mixing angle.
"There is evidence of a fourth type of neutrino and possibly more. The evidence has shown up in different places and it's always marginal. For example, when we look at neutrinos coming from a nuclear reactor, like Daya Bay, we see about 6 percent fewer than we expect from calculation. This can be interpreted as evidence of additional neutrinos mixing with the three known types."
"When astronomers look at the light coming from the earliest moments of the transparent universe, they see ripples of structure which can tell them a lot, including the number of particles involved," Link said. And what numbers do astronomers count? Well, for starters, they count four neutrinos. "When they measure the number of neutrino-like particles they're finding that it's more consistent with four than with three. If it holds up, this extra particle may not be a neutrino at all," Link said. "It may be some other unknown light particle. But if it is another neutrino, it's not a part of the standard model and, interestingly, it does not behave like the other three neutrinos. We call it a sterile neutrino, because it's even less engaged in the world around it than normal neutrinos." The significance of a sterile neutrino could fill in a lot of blanks for scientists involved in questions dealing with the earliest moments of the universe and the nature of matter. [emphasis mine]