Preface

Director of Kamioka Observatory

Yoichiro Suzuki

　Kamioka Observatory, Institute for Cosmic Ray Research, University of Tokyo is located in Hida-city, at the north end of Gifu prefecture and the entrance gate is the Toyama airport in Toyama prefecture. It takes about 40 minutes from the airport to the Observatory. The population of Higashi-Mozumi, Kamioka-town, where our research buildings and dormitory are located is about 50, quiet and nature-full village.  The Kamioka Observatory was established in 1995 to push forward with Super-Kamiokande experiment (SK). This observatory is an inter-university facility and many scientists  are conducting a research here. SK experiment is an international collaboration and about half of the 100 total collaborators come from foreign countries; US , Europe, Korean and Chinese.

 

Kamioka Observatory is a world frontier of the neutrino physics. We have discovered neutrino oscillations by SK which was started its data taking in 1996. This discovery has revealed that neutrinos have finite masses, which was previously considered to be massless, --a clue to a new theoretical frame-work of the elementally particle physics. K2K experiment has confirmed the neutrino oscillation by using the man-made neutrinos. As an extension of K2K, the long base-line neutrino oscillation experiment by using the new accelerator (JPARC)in Tokai will start in April 2009. This aims to discover “the last neutrino oscillation”.

 

The complementary studies to SK are on going. Recently, our knowledge of matter and energy in the universe increases greatly. The 23% of them is found to be  a dark matter which does not emit light, but can be observed by gravity. The dark matter  is expected to be a new elementary particle. The direct observation of the dark matter will be a great help to understand the structure of the universe. A liquid Xenon detector (XMASS) to search for the dark matter has been constructed and will start observation in summer 2009. In addition to that, a gravitational wave telescope has been developed and a laser strainmeter and a superconducting gravimeter are observing vibrations and deformations of the earth for geophysical research. The experiment to search for the dark matter by using a different technique than that of XMASS is in progress. The double beta decay search experiment to study identification of neutrinos and anti-neutrinos is being constructed. We proposed to call these new research field in the underground laboratory, “observational particle physics”.

 

January, 2009

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