A Generalization of Gauge Symmetry, Fourth-Order Gauge Field Equations and Accelerated Cosmic-Expansion

A generalization of the usual gauge symmetry leads to fourth-order gauge field equations, which imply a new constant force independent of distances. The force associated with the new $U_1$ gauge symmetry is repulsive among baryons. Such a constant force based on baryon charge conservation gives a field-theoretic understanding of the accelerated cosmic-expansion in the observable portion of the universe dominated by baryon galaxies. In consistent with all conservation laws and known forces, a simple rotating `dumbbell model' of the universe is briefly discussed.