April 24, 2013
New Matter-Antimatter Asymmetry Discovered, Meaning Remains Unclear
Lee Rannals for redOrbit.com - Your Universe Online
Scientists at CERN have submitted a paper to be published in the journal Physical Review Letters about the first observation of matter-antimatter asymmetry.The team said they made the observation while looking at the decay rate of particles known as B0s mesons. They now say that their findings indicate that antimatter decays at a faster rate than antimatter.
Matter and antimatter are thought to have existed in equal amounts at the beginning of the universe, but today the universe seems to be predominantly composed of matter. Scientists at the Large Hadron Collider are hoping to determine why it is that matter is so much more prevalent than antimatter today, and they believe that this latest observation may provide key insights.
"The discovery of the asymmetric behavior in the B0s particle comes with a significance of more than 5 sigma — a result that was only possible thanks to the large amount of data provided by the LHC and to the LHCb detector´s particle identification capabilities,” says Pierluigi Campana, spokesperson for the LHCb collaboration. “Experiments elsewhere have not been in a position to accumulate a large enough number of B0s decays.”
The preference of matter over antimatter is known as CP-violation. The first violation of CP symmetry was observed at Brookhaven Laboratory in the US in the 1960s in neutral particles called kaons. Scientists performing experiments in Japan and the US forty years later found similar behavior in B0 mesons. Then, experiments by CERN scientists found that the B+ meson also demonstrates CP violation.
"We also know that the total effects induced by Standard Model CP violation are too small to account for the matter-dominated universe,” says Campana. “However, by studying these CP violation effects we are looking for the missing pieces of the puzzle, which provide stringent tests of the theory and are a sensitive probe for revealing the presence of physics beyond the Standard Model.”
In January, scientists said they developed a method that could greatly assist in the study of antimatter. The team wrote in the Journal of Physics B: Atomic, Molecular and Optical Physics that the method could be a significant step towards seeing antimatter actually fall in the field of gravity.
Dark Matter is another mysterious form of matter in the universe. This type of matter cannot be observed with telescopes because it does not interact with light, but scientists believe it exists there because they can see its gravitational influence on other parts of the universe. Earlier this month, scientists announced that they had discovered important evidence indicating that Dark Matter very likely does exist.