Abstract
In 1955, Lee and Yang discussed a new massless gauge field based on the established conservation of baryon number. They predicted the existence of a repulsive force between baryonic matter, just as the conservation of electron–lepton number was later shown to imply the existence of a repulsive force between electrons. Although Eötvös experiments showed the force to be undetectably small at that time, such a force may be related to the dark-energy-induced acceleration of the expansion of the universe. If the gauge invariant Lagrangian involves a spacetime derivative of the field strength, the resultant potential has properties similar to that of the "dark energy" implied by the cosmological constant in the Einstein's equation.