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New evidence on how the early universe survived: Why matter prevails over antimatter

In “Evidence for Antimatter Anomaly Mounts” (Science, February 29, 2012),
Jon Cartwright reports,

The big bang created a lot of matter—along with the same amount of antimatter, which wiped out everything and brought the universe to an untimely end. That’s what accepted theoretical physics tell us—though things clearly didn’t work out that way. Now, 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.

n November, the LHCb team reported that the decay rates differed by 0.8%—some eight times the amount the standard model is generally expected to allow, and perhaps enough to help explain the origin of matter’s prevalence over antimatter. Unfortunately, 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.bl2

The latest CDF results—announced earlier today at a meeting in La Thuile, Italy—drastically decreased the odds of a fluke. They point to CP violation at the level of 0.6%, with a statistical significance of 2.7 sigma. 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.

Not proven to 5 sigma standards (less than one in a million chance of a fluke) but definitely worth pursuing.

See also: “New twist in antimatter mystery” (Paul Rincon, BBC News, 29 February 2012):

Physicists think the intense heat of the Big Bang should have forged equal amounts of matter and its “mirror image” antimatter. Yet today we live in a Universe composed overwhelmingly of matter.

Antimatter is relatively uncommon, being produced at particle accelerators, in nuclear reactions or by cosmic rays. Getting to the bottom of where all this antimatter went remains one of the great endeavours of particle physics.

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