At the Neutrino 98 conference (XVIII International Conference on Neutrino Physics and Astrophysics) held in Takayama, Japan, June 4 - 9, 1998, the Super-Kamiokande collaboration has reported an evidence for massive neutrinos. A group of experimental particle physicists from Stony Brook led by Prof. Chang Kee Jung is part of the US team in the Super-Kamiokande collaboration which is composed of about 120 physicists including graduate students from 23 institutions from Japan and US. (The participating US institutions are: Boston University, Brookhaven National Laboratory, University of California, Irvine, California State University, Dominguez Hill, George Mason University, University of Hawaii, Los Alamos National Laboratory, Louisiana State University, University of Maryland, College Park, State University of New York at Stony Brook, and University of Washington.)
It was reported that there is strong evidence for neutrino oscillation (muon neutrino to tau neutrino) in the atmospheric neutrino data taken with the Super-Kamiokande detector in the past two years. The finding is a major discovery with a far reaching impact in the elementary particle physics, cosmology and astrophysics. The phenomenon of neutrino oscillation which requires neutrinos to have non-zero mass will alter our view of the world of elementary particles, and the Standard Model, the currently prevailing theory of the elementary particles, must be modified. In the Standard Model the neutrinos have zero mass. The finding will also make the theories of the Grand Unification more viable and attractive, and make the universe a lot heavier than we currently assume.
The neutrino oscillations and the neutrino mass have been the subject of intense research both theoretically and experimentally in the elementary particle physics field for about four decades since the discovery of neutrinos in 1956 by Reines and Cowen, and in 1963 by Lederman, Schwarz and Steinberger. In the past, several experiments have claimed discovery of neutrino oscillations or observation of non-zero neutrino masses but none remain as established fact. At present, there are various indications that the neutrinos do oscillate. The situation is, however, far from clear.
Super-Kamiokande is a very large water Cherenkov detector experiment (50,000 ton) being carried out at a mine in Japan. The experiment searches for proton decays and studies a variety of neutrino physics: solar neutrinos, atmospheric neutrinos, and supemova neutrinos. And it searches for neutrinos from gamma ray bursters, active galactic nuclei and other astrophysical sources. One fascinating aspect of this experiment is that one can study such variety of crucial physics topics with a relatively simple detector essentially composed of water and photomultiplier tubes. The experiment started taking data on April 1, 1996.
To confirm the above finding, another experiment (K2K experiment) is being constructed in Japan in which Prof Jung serves as a US co-spokesperson. K2K is a long baseline neutrino oscillation experiment which uses sophisticated particle detectors at KEK laboratory in the east coast of Japan as a near detector and the Super-Kamiokande detector in the west coast of Japan, 250 km away from KEK, as a far detector. The detector design and construction is being done throughout this year and the data taking run of the experiment will start in January 1999.
The Stony Brook Super-Kamiokande/K2K group is composed of a faculty (Prof. C. K. Jung), a senior research scientist (Dr. C. Yanagisawa), three research associates (Drs. J. Hill, K. Martens, C. McGrew), three graduate students (C. Mauger, E. Sharkey, B. Viren) and three undergraduate students (T. Kato, M. Pawlowski, and T. Raza). Two undergraduate students (J. Andrello and Y. Nakazawa) have just graduated. In the past, a total of three graduate students and eleven undergraduate students have done research work with the group, many of whom have traveled to Japan to participate in the detector construction and related research activities. The Stony Brook group has been participating in the Super-Kamiokande experiment since 1992, and in the K2K experiment since 1996.
For further information contact: Prof. Chang Kee Jung, Dept. of Physics and Astronomy, SUNY at Stony Brook, Stony Brook, NYI 1794-3800, or call: 631-632-8108, or send an e-mail to: alpinist@superk.physics.sunysb.edu
For more about the SuperK group at Stony Brook, go to their Web page at http://superk.physics.sunysb.edu/
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