Baryon asymmetry

Imbalance of matter and antimatter in the observable universe

In physical cosmology, the baryon asymmetry problem, also known as the matter asymmetry problem or the matter–antimatter asymmetry problem, is the observed imbalance in baryonic matter and antibaryonic matter in the observable universe. As the two form and behave in nearly identical ways, it is expected that they would have been created in near equal portions by the Big Bang, but, in reality, matter makes up the vast majority of the universe. Neither the Standard Model of particle physics nor the theory of general relativity provides an explanation for why this should be so.

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