| Project/Area Number |
14540271
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | KYUSHU UNIVERSITY (2004)
University of the Ryukyus (2002-2003) |
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Principal Investigator |
YAHIRO Masanobu Kyushu University, Faculty of Science, Professor, 大学院・理学研究院, 教授 (40300537)
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| Co-Investigator(Kenkyū-buntansha) |
KAJINO Toshitaka National Astronomical Observatory, Associate Professor, 理論研究部, 助教授 (20169444)
KANIZATO Suneo University of the Ryukyus, Faculty of Science, Associate Professor, 理学部, 助教授 (60045002)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2004: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2003: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2002: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | dark matter / braneworld cosmology / big bang nucleosynthesis / cosmic microwave background / type IA supernova observation / 実証論的宇宙論 / Brane-world宇宙論 / 銀河団 / Quintessence |
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| Research Abstract |
This research analyzed the origin of the dark matter and the possibility of higher dimensional spacetime from the viewpoint of the Quintessence model (self-interacting scalar field model) and the higher-dimensional cosmology. The Randall-Sundrum model is one of the most interesting models among various types of higher-dimensional cosmologies proposed so far. In the model, our universe is described as a membrane (brane) of four dimensions which appears in the five dimensional spacetime. The validity of these models was analyzed by using three important observations (big bang nucleosynthesis, cosmic microwave background, type IA supernova observation). A main conclusion is summarized in the following.
1.The amount of darkness radiation, which is generated by the gravity in the higher dimensional spacetime, was constrained by the three observations.
2.Assuming the dark matter is the massive particle which can be described as the five-dimensional scalar field, we showed that the dark matter is trapped on our brane only during a limited time.
3.Using the result of 2,we proposed a model called "disappearing dark matter", in which the dark matter trapped on the brane decays into the higher-dimensional spacetime in a finite time. The decaying time was estimated by the three observations. The life time was found to be around the cosmic age.
4.We derived Newton's law in the Randall-Sundrum model in which the model parameter is tuned to have the positive cosmological constant. The resultant form is different from the inverse square law at small distance.
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