Evidence for antimatter anomaly mounts

March 1, 2012 | Source: Science Now

If matter and antimatter aren't exact opposites, it may explain why the universe still exists (credit: Fermilab)

Results from a U.S. particle smasher are providing new evidence for a subtle difference in the properties of matter and antimatter that may explain how the early universe survived.

Physicists have long suspected that a difference in the properties of matter and antimatter is key to the early universe’s survival. Such a difference — technically known as charge-parity (CP) violation — would have allowed normal matter to prevail over antimatter so that normal matter could go on to form all of the stuff we see in the universe today.

To witness CP violation, the LHCb detector at CERN, and CDF at Fermilab, study particles to see if there is any difference in the rate of decay between normal particles and their antiparticles. In November, the LHCb team reported that the decay rates differed by 0.8%, but the measurement was not very precise: The statistical significance was about 3 sigma, meaning there was about one chance in a 100 that it was a random blip in the data.

The latest CDF results drastically decreased the odds of a fluke. They point to CP violation at the level of 0.6%. Combined with the previous LHCb results, the CDF results bring the significance to about 3.8 sigma—or about one chance in 10,000 that the CP violation is a random blip.