1994 Fiscal Year Final Research Report Summary
STUDY ON THE SPIN STRUCTURE OF NUCLEONS
| Project/Area Number |
05044046
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | Nagoya University |
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Principal Investigator |
HORIKAWA Naoaki Nagoya University, Faculty of Science, Associate Professor, 理学部, 助教授 (70022697)
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| Co-Investigator(Kenkyū-buntansha) |
SAVIN I. Joint Institute for Nuclear Research, Dubna, RUSSIA,Professor, JINR研究所, 教授
NIINIKOSKI Tapio European organization for nuclear Research, Research Associate, 研究員
IGO G.J. カリフォルニア大学, 物理学科, 教授
HUGHES V.W. エール大学, 物理学科, 教授
SAWADA Shoji Nagoya University, Faculty of Science, Professor, 理学部, 教授 (50022546)
YASUNO Masaru Nagoya University, Faculty of Science, Professor, 理学部, 教授 (30022544)
ISHIMOTO Shigeru National Laboratory for High Energy Physics, Research Associate, 助手 (50141974)
MATSUDA Tatsuro Miyazaki University, Faculty of Engineering, Research Associate, 工学部, 助手 (20253817)
HASEGAWA Takeo Miyazaki University, Faculty of Engineering, Professor, 工学部, 教授 (70025386)
MORI Kunikazu Nagoya University, College of Medical Techmology, Professor, 医療技術短期大学部, 教授 (70022663)
IWATA Takahiro Nagoya University, Faculty of Science, Research Associate, 理学部, 助手 (70211761)
IGO George California University, Professor
HUGHES Vernon Yale University, Professor
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| Project Period (FY) |
1993 – 1994
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| Keywords | Spin / Nucleon Spin / Quark Spin / Spin Polarized Target / Spin Polarized Muon Beam / Ellis-Jaffe Sum Rule / Bjorken Sum Rule / Spin Crisis |
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| Research Abstract |
SMC (Spin Muon Collaboration) is now going on the experiment using the high energy polarized muon and polarized proton/deutron targets. This experiment aims at making clear the origin of the nucleon spin and cheking the validity of the QCD which is used for the prediction of the quark-gluon behavior inside hadrons. SMC has performed two experiments in this term (2 years) at CERN.In 1993, the spin dependent structure function of the proton has been measured. In 1994, the same parameter of the deuteron was measured. The former experiment extended the data points to the lowest x region with higher statistics. The latter data are now under analysis.
The measurement of the spin-dependent structure function of proton has been achieved under the following conditions. (1) The polarized muon beam had an intensity of 4*10^7ppp with a polarization of 80%. (2) The polarized proton target has a dimension of 50mmphi* 650mmlong. A pair of this target capsuls are installed in a dilution cryostat with opposite direction of the polarization. The value of the polarization was about 45%. The data extended the x-region to 0.003 with fairly better statistical and systematic errors. Whole number of data was 4.4*10^6 events.
From the proton data, the following results are derived. (1) The Eliis-Jaffe sum rule which is calculated by the assumption of naive quark model is not valified by the experiment. There is about two standard deviation between the prediction and measurement. (2) The sum of the quark spins inside proton can bring only 22% and the strange quark spin has a contribution of -12%. This requires to look for the origin of nucleon spin. (3) The Bjorken sum rule which is a key relation to check the QCD was tested and guaranteed to be correct within errors.
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Research Products
(10 results)
