| Project/Area Number |
23540312
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | Saga University |
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Principal Investigator |
FUNAKUBO Koichi 佐賀大学, 工学(系)研究科(研究院), 教授 (60221553)
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| Project Period (FY) |
2011 – 2013
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| Project Status |
Completed (Fiscal Year 2013)
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| Budget Amount *help |
¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2013: ¥390,000 (Direct Cost: ¥300,000、Indirect Cost: ¥90,000)
Fiscal Year 2012: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000)
Fiscal Year 2011: ¥390,000 (Direct Cost: ¥300,000、Indirect Cost: ¥90,000)
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| Keywords | バリオン数生成 / 電弱相転移 / レプトン数生成 / ボルツマン方程式 / 有限温度有効ポテンシャル / 有限温度相転移 / 温度グリーン関数 / 高次摂動計算 |
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| Research Abstract |
To describe states out of equilibrium in the early universe, the integrated Boltzmann equations have been used assuming the distribution functions of the particles have the same momentum-dependence as those in equilibrium. Proper treatment of nonequilibrium states is necessary to evaluate the abundances of the dark matter and baryonic matter. In the context of thermal leptogenesis, we studied the evolution of the distribution function of the heavy neutrino and calculate the lepton number asymmetry including the effects of the lepton-number-violating processes.
We also developed a method to evaluate the effective potential, which are used to study the phase transitions, with the resummation of the thermal masses, without recourse to the high-temperature expansion. We applied it to the abelian Higgs model and obtained the two-loop resumed effective potential, which indicates a weaker symmetry-breaking phase transition than the previous studies with the high-temperature expansion
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