A Model for Dark Energy Based on Baryonic Charges with General Yang-Mills Symmetry

General Yang-Mills symmetry and Yang-Mills gravity in inertial frames presents a possible avenue for understanding dark energy phenomenon in terms of the extremely small baryon charges of protons and neutrons. General gauge transformations involve vector gauge functions and Hamilton's characteristic phase functions rather than scalar gauge functions and usual phase functions. One has fourth-order gauge field equations, which lead to a static linear potential between two point baryonic charges. Together with gravitational force, the model predicts that in the early universe, when the gravitational force was dominant, not only was the expansion occurring at a decreasing rate, the rate of change of the deceleration was decreasing due to a $1/r^2$ dependence. In the present universe, when the baryonic force is dominant, the cosmic acceleration should be approximately constant and has a maximum value $a_{max}\approx 10^{-13} m/s^2$, as measured in an inertial frame. We hope that these properties of the late-time cosmic acceleration can be tested in the future.