STRONG INTERACTION PHYSICS FROM HADRONIC ATOMS

Hadronic atoms provide a unique laboratory for studying strong interac tions and nuclear medium effects at zero kinetic energy. Previous resu lts from analyses of strong-interaction data consisting of level shift s, widths and yields in pi(-), K-, (p) over bar and Sigma(-) atoms are reviewed. Recent results from fits to comprehensive sets of data in t erms of density-dependent optical potentials that respect the low-dens ity limit. where the interaction tends to the free hadron nucleon valu e, are discussed. The importance of using realistic nuclear density di stributions is highlighted. The introduction of density dependence in most cases significantly improves the fit to the data and leads to som e novel results. For K- atoms, a substantial attraction of order 200 M eV in nuclear matter is suggested, with interesting repercussions for (K) over bar condensation and the evoIution of strangeness in high-den sity stars. For (p) over bar atoms it is found that a reasonable p-wav e strength can be accommodated in the fitted optical potential, in agr eement with the energy dependence observed for some low-energy (p) ove r bar N reactions. For Sigma(-) atoms, the fitted potential becomes re pulsive inside the nucleus, implying that Sigma hyperons generally do not bind in nuclei in agreement with recent measurements. This repulsi on significantly affects calculated masses of neutron stars.