Experiments with the MD-1 detector at the e+e- collider VEPP-4 in the energy region of Υ mesons

This paper reviews physical results obtained at the e+e- collider VEPP-4 with the MD-1 detector. The results of experiments on the Υ meson physics and study of the hadron production in continuum in the energy region 7.2-10.3 GeV as well as the results of study of the two photon reactions are presented. Among results obtained in the upsilon physics: the precise measurement of the Υ(1S), Υ(2S), Υ(3S) masses and the precise determination of the Υ(1S) and Υ(2S) electronic widths. In the experiments on study of the hadron production in continuum the precise measurement of the R was carried out. The peculiarity of the detector is the magnetic field transverse to the orbit plane which provided the possibility to study two photon reactions with tagging one or both scattered electrons even at zero emission angle. Among results on the γγ reactions is the measurement of the two photon total hadronic cross section performed in the double-tag mode. In the QED experiments a new QED effect - the impact parameter cut-off in single bremsstrahlung was discovered. (orig.)