According to, matter and anti-matter should have been created in equal amounts at the 'beginning' of the Universe. And, in experiments with high-energy particle accelerators, that is exactly what happens. Baryons (i.e. 'heavy' particles such as neutrons, protons, and their constituent quarks) and their anti-particle equivalents (anti-baryons) are created in equal numbers.
It's currently estimated, however, that (in 'natural' conditions outside the laboratory) :
The Standard Mode prediction for the ratio of baryons over antibaryons deviates from the astrophysical observations by eight orders of magnitude.â€ś
Source; Proceedings, 26th International Nuclear Physics Conference (INPC2016)
There could be areas of the universe where antimatter dominates - but no observations have so far identified regions in space where antimatter and matter encounter each other - catastrophic zones which would be easily detectable due to the radiation that would be produced.
To compound the mystery :
Theories that explain this apparent asymmetry violate other measurements.â€ť
Source : NASA AMS-02 project.
Further reading: New Scientist , April 2009
For technical info, see : Baryogenesis and Leptogenesis J. Phys.: Conf. Ser. 335, 012008
New research conducted at CERN has attempted to find fundamental differences between protons and anti-protons. Without success. Finding asymmetries could explain how one form (matter) is dominant in the universe.
See: Riddle of matter remains unsolved: Proton and antiproton share fundamental properties Press release, Johannes Gutenberg-UniversitĂ¤t Mainz, Oct. 2017
Also see :
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