A quark can have one of three "colors", dubbed "red", "green", and "blue"; while an antiquark may be either "anti-red", "anti-green" or "anti-blue".
[1] For normal hadrons, a white color can thus be achieved in one of three ways: The baryon number was defined long before the quark model was established, so rather than changing the definitions, particle physicists simply gave quarks one third the baryon number.
In 2015, the LHCb collaboration at CERN reported results consistent with pentaquark states in the decay of bottom Lambda baryons (Λ0b).
Such particles are The baryon number is conserved in all the interactions of the Standard Model, with one possible exception.
The one exception is the hypothesized Adler–Bell–Jackiw anomaly in electroweak interactions;[4] however, sphalerons are not all that common and could occur at high energy and temperature levels and can explain electroweak baryogenesis and leptogenesis.
The hypothetical concepts of grand unified theory (GUT) models and supersymmetry allows for the changing of a baryon into leptons and antiquarks (see B − L), thus violating the conservation of both baryon and lepton numbers.
The conservation of baryon number is not consistent with the physics of black hole evaporation via Hawking radiation.
[6] It is expected in general that quantum gravitational effects violate the conservation of all charges associated to global symmetries.
[7] The violation of conservation of baryon number led John Archibald Wheeler to speculate on a principle of mutability for all physical properties.