Recent results from CESR

Recent experiments carried out at the Cornell Electron Storage Ring (CESR) are described. Some modifications of instrumentation (e.g. superconducting magnets for detectors) were performed to improve the resolution and accuracy. Main beam optical data of the CESR and its operation (luminosity, event numbers) are presented. The main objective of the experiments was the study of upsilon resonances near 10 GeV center of mass energy. The spectroscopy of upsilon (3 S) states gave a detailed picture of level structure of upsilon system. Comparison of the known quarkonium system (psi and upsilon family) is discussed. The photonic transitions of upsilon system is investigated and mixing masses are determined. The background conditions of experiments are analysed. Search for axion decay of upsilon states was performed, and limits of branching ratios are given. Future plans, modifications of instrumentation and planned experiments are described. (D.Gy.)