SOME URGENT PROBLEMS IN MEDIUM AND HIGH-ENERGY NUCLEAR-PHYSICS

In this article, I wish to elucidate some problems which I believe are urgent in the area of medium and high energy nuclear physics. First, the adoption of the parton-model description of hadrons in high energy physics experiments has, over the last two decades, generated a conceptual gap from the meson-baryon picture which is still used as the standard language in medium or high energy nuclear physics. We suggest that the key to bridge the gap is to try to understand, or to derive, the various parton distributions at low or moderate Q(2) (say, up to a few GeV2) using the meson-baryon picture. As the second urgent problem in nuclear physics, I wish to echo the standard wisdom that strong interaction physics, as based on quantum chromodynamics (QCD), must be treated in a quantitative manner for low- or medium-energy processes involving hadrons. Here we have chosen to follow the route of using QCD sum rules to offer some solutions, as an alternative to the commonly accepted approach based upon lattice simulations. Finally, I believe that it is highly essential, and of urgently important, to employ what we have learned in nuclear and particle physics to formulate, or to reformulate, certain problems in related areas such as astrophysics and cosmology.