- Baryon asymmetry
The baryon asymmetry problem in
physics refers to the apparent fact that thebaryon s in the universe which have been observed are overwhelminglymatter as opposed toanti-matter . Neither the standard model ofparticle physics , nor the theory ofgeneral relativity provide an obvious explanation for why this should be so. There are competing theories to explain this aspect of the phenomena ofbaryogenesis , but there is no one consensus theory to explain the phenomenon at this time.One possible explanation of baryon asymmetry is that there are regions of the universe in which matter is dominant, and other regions of the universe in which anti-matter is dominant, which are widely separated and thus do not interact. Approximately 30 years of scientific research have placed boundaries on how far away, at a minimum, any such region would have to be, and hence, this explanation is now considered rather unlikely, as matter seems to be not spaced that dilutely. At least one more major scientific study called the
Alpha Magnetic Spectrometer (AMS) is planned to further refine that limit cite news | title=The hunt for antihelium: finding a single heavy antimatter nucleus could revolutionize cosmology | first=Patrick | last=Barry | work=Science News | date=2007-05-12 | url=http://www.sciencenews.org/view/feature/id/8504/title/The_Hunt_for_Antihelium | archiveurl=http://findarticles.com/p/articles/mi_m1200/is_19_171/ai_n27261210 | archivedate=2008-07-26 ] , although it is facing funding problems. [cite news | title=Antimatter device loses ride to space | first=Klotz | last=Irene | work=ABC Science | date=2007-03-26 | url=http://www.abc.net.au/science/news/stories/2007/1881394.htm ]As of May, 2007, no helium atom (or larger atom) made of anti-matter, either in nature, or created synthetically, has ever been scientifically observed. As a result, scientific limits on the possible quantity of such anti-matter atoms in existence in nature, and hence, of the extent of baryon asymmetry, are essentially a function of the accuracy of the scientific instruments used to detect them. While anti-matter atoms of any type are theoretically possible given existing scientific understanding, the failure of scientists to scientifically observe any helium or larger sized anti-matter atoms supports both the idea that anti-matter is very rare in our cosmic vicinity, and the idea that there are no helium or larger sized anti-matter atoms anywhere in nature.
ee also
CP-violation References
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