Immediately after the Big Bang, the earliest elementary particles fought for supremacy, with matter emerging victorious over antimatter. Exactly how that happened, though, had remained mysterious until now, as new data suggest a particular particle was key to matter's success.
One of the fundamental mysteries of the universe is why matter came to dominate antimatter, particularly considering the two complementary sets of particles initially formed in equal quantities. It's hardly a trivial concern - if matter had not so thoroughly outstripped its counterpart, humans couldn't possibly exist, not to mention pretty much everything else in the universe. After eight years of tests at FermiLab at the University of Chicago, physicists think they have a tentative answer.
Using the Tevatron Collider in Batavia, Illinois, scientists discovered that B mesons, a type of subatomic particle, do not decay into equal amounts of matter and antimatter, as previously thought. Rather, they produce about one percent more muons (a heavier counterpart of electrons) than antimuons, resulting in a net gain of positive matter.
A one percent difference might not sound like much, but it's more than enough to account for the initial imbalance that led to the universe of matter. In fact, it's about fifty times the amount of extra muons that would have been predicted by the standard models of particle physics. That means that these tests are some of the best concrete proof for the more exotic theories of physics that have been put forth in the last couple of decades. Possible theories to explain this relatively huge imbalance between muons and antimuons include supersymmetry, which holds that all subatomic particles have still unknown heavier counterparts, interaction with messenger particles in hidden dimensions, and a fourth family of quarks.
The results themselves aren't really in doubt - there's only about a 0.1% chance that the results of these tests were unrepresentative of normal B meson disintegration. The wider implications, however, do remain controversial, as there is not as yet an obvious way to fit these new results in with existing observations, and this mechanism may ultimately be a red herring in the hunt for the cause of the matter/antimatter imbalance. The current hope is that the Large Hadron Collider will be able to follow on from the Tevatron's work once it comes back online, and this study has physicists hopeful that there really are new and illuminating elementary particles waiting to be discovered.