INVESTIGATION OF EARY UNIVERSE BASED ON UNIFIED THEORIES
| Project/Area Number |
08640341
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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 | TOHOKU UNIVERSITY |
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Principal Investigator |
YOSHIMURA Motohiko TOHOKU UNIVERSITY,DEPARTMENT OF PHYSICS,PROFESSOR, 大学院・理学研究科, 教授 (70108447)
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| Project Period (FY) |
1996 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1997: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1996: ¥800,000 (Direct Cost: ¥800,000)
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| Keywords | COSMOLOGY / DARK MATTER / RELIC ABUNDANCE / INFLUENCE FUNCTIONAL / BOLTZMANN EQUATION / GIBBS FORMULA / WIMP / LSP / バリオン非対称 / 対消滅の凍結 / 量子散逸 / 粒子崩壊 / 宇宙初期 / 宇宙初期現象 / インフレーション / パラメータ共鳴 |
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| Research Abstract |
In most previous study of physical cosrnology effect of cosmic environment has been evaluated by using the Boltzmann equation suitably averaged in thermal medium. This approach is based on the on-shell S-matrix element, tire transition matrix element between the infinite past and the h6 : rite future, 'and neglects subtle quantum mechanical correlation at 6nite intermediate times of the on-going process. In the present investigation a fully quantum mechanical approach is adopted, using the in influence functional method. In particular, pair annihilation of heavy stable particle that occurs in the early universe was investigated, and quantum kinetic equation for the momentum distribution of the annihilating particle has been derived.
A crossing symmetric Hartree approximation that determines self-consistently the equilibrium distribution is developed, and its Markovian approximation is shown to generalize the Boltzmann equation, including off-shell effects. The off-shell effect is dominant at low temperatures. The deck changes the equilibrium distribution from the familiar 1/(e^<omegamu/gamma>-1) modified one given by a Gibbs formula. Integrated over momenta, tire particle number density becomes roughly of order (coupling) * ROO<T/M>・T^3 at low 'temperatures for the S-wave annihilation. The relic mass density in the present universe is insensitive the coupling strength in a large range of the mass and the coupling parameters, and scales with the VAMP mass as <approximately equal> 6*10^4eVcm^<-3>(M/geV)^<4/3>
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Report
(4 results)
Research Products
(20 results)
