1995 Fiscal Year Final Research Report Summary
The measurement of a tau-neutorino mass
| Project/Area Number |
05044047
|
|---|
| Research Category |
Grant-in-Aid for international Scientific Research
|
| Allocation Type | Single-year Grants |
|---|
| Section | Joint Research |
|---|
| Research Institution | Nagoya University |
|---|
Principal Investigator |
NIWA Kimio School of Science, Nagoya Univ.Professor, 理学部, 教授 (60113445)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
SONG J.s. Gyeongsang National Univ.Professor, 教授
SMIRNITSKY V. ITEP Professor, 教授
TOLUNN P. Ankara Univ.Professor, 教授
BARONI G. Rome Univ.Professor, 教授
WINTER K. CERN Professor, 教授
SHIBUYA Hiroshi Faculty of Science, Toho Univ.Assoc.Prof., 理学部, 助教授 (40170922)
HARA Toshio Faculty of Science, Kobe Univ.Assoc.Prof., 理学部, 助教授 (50156486)
AOKI Shigeki Faculty of Human Development, Kobe Univ.Assoc.Prof., 発達科学部, 助教授 (80211689)
OKUSAWA Toru Faculty of Science, Osaka City Univ.Assoc.Prof., 理学部, 助教授 (60047397)
NAKAMURA Mitsuhiro School of Science, Nagoya Univ.Res.Assoc., 理学部, 助手 (90183889)
HOSHINO Kaoru School of Science, Nagoya Univ.Assoc.Prof., 理学部, 助教授 (70022738)
|
|---|
| Project Period (FY) |
1993 – 1995
|
| Keywords | Neutrino oscillation / Neutrino mass / Tau-neutrino / Dark matter / Emulsion / Scintillating fiber |
|---|
| Research Abstract |
CHORUS is the international project using the neutrino beam from super proton synchrotrn (SPS) of CERN (Center of Europ organization for Research of Nuclus). The object of this project is to observe the mass of tau-neutrino by the method of the oscillation from mu-neutrino to tau-neutrino. The identification of tau-neutrino could be done by detecting the produced tau by observing the trace of tau from produced point to the decay point in the photographic nucler emulsion.
The detecter have many parts, target spectrometer calorimeter and muon spectrometer. We are contributing on the target the most important target of this experiment. This target has the sandwich structure of emulsion sheets and fiber trackers.
The neutrino exposure has been finished on Novenber in 1995. The emulsion analysis, the most difficult job in this project, has been done by using Automatic emulsion analysis system originally developed by physists of Nagoya university. The number of analyzed neutrino interaction in the emulsion is more than 7700 neutorino interactions by 4 month scanning. This number is about 15% of all CHORUS, but already this number is 2 times higher than the most sensitive similler experiment, named E531 done in 1978. This experiment is sensitive to 1 eV in tauneutrino mass and 1% in mixing tau-neutrino to mu-neutrino.
To finish all of the analysis, it take more two years.
|
