| Project/Area Number |
10044069
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
SHIBATA Toshi-aki Tokyo Institute of Technology Dept.Physics, Professor, 理学部, 教授 (80251601)
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| Co-Investigator(Kenkyū-buntansha) |
SAKEMI Yasuhiro Tokyo Institute of Technology Dept.Physics, Research Assistant, 理学部, 助手 (90251602)
BRIILL A. 原子核のマックスプランク研究所(独), 研究員
POVH B. 原子核のマックスプランク研究所(独), 所長
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,900,000 (Direct Cost: ¥3,900,000)
Fiscal Year 1999: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1998: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | proton / neutron / quark / scattering / electron / polarization / gluon / spin / 深非弾性散乱 / 核子 / エアロジェル / リングイメージチェレンコフ検出器 / HERMES / DESY-HERA / リング・イメージ・チェレンコフ検出器 |
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| Research Abstract |
In this project of Grand-in-Aid we have studied how the spin of proton and neutron, which is 1/2, is composed of quarks and gluons with use of experimental techniques. It is a research of Quantumchromodynamics which is a theory of strong interaction.
We participated in HERMES experiment at DESY in Germany. The high energy polarized electron beam is scattered off the polarized target nucleon. The scattered electron as well as produced hadrons in the final state (mesons, nucleons, lambdas etc.) were detected in coincidence. The data were sent to the collaborating universities and institutes worldwide. The data-analysis equipment at Tokyo Institute of Technology played an important role in the data-analysis. The results were published in journals.
During this project a Ring Imaging CHerenkov Counter (RICH) was developped and installed into HERMES experiment. Pions, kaons, protons and anti-protons are now identified with the RICH.Polarized u, d, and s quarks in the nucleon can be studied. Their momentum distributions have been determined. Pion-kaon separation had been difficult above several GeV/c up to now but HERMES solved it with the RICH.This technical breakthrough has a large impact.
As an outcome of phycics, the largest achievement is that the transversely polarized quark distribution was studied. We realized this by looking at the azimuthal angle which is the angle between the electron scattering plane and the pion production direction. The dependence on the target spin direction of the azimuthal angle distribution was measured. This way the distribution of the quark which has the spin perpendicular to the uncleon spin is studied. This will become a new field of research and attract a large number of physicists to further investigate this subject.
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