123Experimental Physics Division (EPD) at AANL (Yerevan Physics Institute) has had a long lasting tradition of experimental research in a wide range of topics since the operation of Yerevan electron synchrotron (ARUS) with energy of up to 6 GeV in 1967.
123Despite a large volume of research carried out or planned in the USA (Cambridge-5 GeV, Cornel-9 GeV, SLAC-20 GeV), in Germany (DESY-6 GeV), and England (NINA-4 GeV) at that time, physicists of YerPhI succeeded in receiving a number of important results which promoted the understanding of hadron and nuclei structure and fundamental properties of elementary particles interaction.
123During 1970-1991 years the Yerevan synchrotron operated productively and many scientific results have been obtained in the energies range up to 4,5 GeV, including: the measurement of the proton and neutron electromagnetic radii,the study of hadronic properties of photons in reaction of π - meson photoproduction on nuclei, structures of nucleon resonances in multi-polarization experiments, structure and characteristics of a nuclear matter, study of properties of X-ray transition radiation and radiation of relativistic electrons at channeling in monocrystals, etc.
123In 1980 academician H.Vartapetian (Deputy Director of YerPhI in 1974-1993) with a group of his colleagues was awarded the State Prize of the Armenian Soviet Socialistic Republic for an outstanding contribution and remarkable scientific results obtained at YerPhI’s synchrotron.
123The YerPhI experimental physics program included following researches: study of
123123· properties and structures of baryons ( nucleons and nucleon resonances)
123123· few nucleon systems properties
123123· excited nuclear systems properties
123123· nuclear matter in short distance
123123. electron interaction with crystals
123123. methodical studies
123Since 1991, when the accelerator was stopped because of an energy crisis in Armenia, only short-term experiments have been periodically performed.
123The reputation of the Institute as the nuclear physics and accelerator center during the most difficult years of 1991-1996 lets us preserve and develop international collaborations with scientific centers of the USA, Germany, Switzerland and others, fully participating in the experimental research program in these centers.
Brief summary of scientific results for the period of 1970-1991
123The main achievements of the YerPhI in high energy experimental particle and nuclear physics obtained by EPD scientists on Yerevan synchrotron for the period of 1970-1991:
123As an achievement we can mention the experiment, performed in our underground laboratory together with ITEP (Moscow), in which the first observation of two-neutrino double beta decay of 76Ge was made, and the most stringent limit (for that time) on half-life of neutrinoless double beta-decay in this germanium isotope was set. It allowed us to estimate the lowest upper limit for Majorana mass of neutrino .