Time is something we all live with as it marches on, out of the past and into the future, but in the quirky quantum realm, this is not the case. There a particle should have time symmetry, which means that to the particle there is no difference when time flows forward or backward; it will behave the same either way. Researchers at the SLAC National Accelerator Laboratory however have found that this is not the case and that some behaviors do indeed prefer one direction of time to another.
The BaBar experiment looked at the decay of B mesons and their antimatter counterparts, B-bar mesons, over the course of ten years. Researchers had previously found that these particles violate charge-parity symmetry, but according theory, if charge, parity, or time symmetry is violated, then another symmetry must be violated as well. After going through the ten years of data the researchers have managed to confirm, with a 14-sigma level of certainty (a 1 in 1043 chance of being the result of error), that the other symmetry violated is time as the particles prefer to decay in one direction over another.
This result is very important for potentially understanding the Universe itself. The Big Bang theory cannot explain why more matter was created than antimatter, but if there is a difference between their behaviors, as this research shows, that could explain it.