Neutrinos, the chargeless particles that course through your body every moment by the billion, should essentially behave the same way as their anti-particle, the anti-neutrino. But two experiments today presented evidence that, maybe, the cousins might behave quite differently. The difference could be new evidence that an expected symmetry in neutrinos is not conserved. And that in turn would provide physicists with another mechanism for explaining the prevalence of matter over anti-matter in the Universe.

The results are “suggestive” and “weird”, says Richard Van De Water, co-spokesperson for one of the experiments, MiniBooNE. “We don’t really know what’s going on,” says Van De Water, who gave a talk on the subject today at a major neutrino conference in Athens, Greece. Another experiment from Fermi National Accelerator Laboratory, MINOS, also presented new results on neutrinos and anti-neutrinos that suggest they might play by different rules.

The MiniBooNE results in particular, however, could come as a delayed vindication for LSND, an anti-neutrino experiment at Los Alamos National Laboratory that in the mid-1990s found a strange anomaly. In that experiment, a type of neutrino appeared at a level that suggested the neutrino family as whole might have to grow to include “sterile neutrinos” — which would have been a radical new member of the particle zoo, beyond physicists’ Standard Model.

MiniBooNE was brought in to confirm or refute LSND. And initially, using a beam of neutrinos, it refuted LSND. But the MiniBooNE collaboration began collecting statistics again, only this time with a stream of anti-neutrinos, just as LSND did. Based on the results presented in Athens, MiniBooNE has now confirmed the LSND anomaly with a confidence of 99.4% — or just under a 3 sigma significance. In the physics world, that’s not nearly enough evidence to claim a discovery. But the hints will certainly catch the attention of theorists, who already had other reasons to think that the discovery of sterile neutrinos might be nigh.