| Project/Area Number |
15K17644
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | Nagoya University |
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Principal Investigator |
Miura Kohtaroh 名古屋大学, 基礎理論研究センター, 研究員 (50511432)
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| Project Period (FY) |
2015-04-01 – 2018-03-31
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| Project Status |
Completed (Fiscal Year 2017)
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| Budget Amount *help |
¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2016: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2015: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
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| Keywords | ニュートリノ集団励起とレプトン数生成 / 物質-反物質非対称性 / 素粒子論的宇宙論 / 電弱相転移と素粒子集団励起 / Leptogenesis / 素粒子(lepton)の集団励起 / 高温初期宇宙 / 有限温度ゲージ理論 / 宇宙の物質-反物質非対称性 / 電弱-TeVスケ－ル宇宙 / Resonant Leptogenesis / 右巻きニュートリノ崩壊率 / 有限温度 / 発散回避メカニズム / 非自明なスペクトル関数 |
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| Outline of Final Research Achievements |
We have investigated a creation mechanism of matter-antimatter asymmetry observed in the Universe in terms of a collective excitation of elementary particles in the electroweak phase transition (EWPT) era. We have focused on the resonant-leptogenesis in which the lepton number would be created at around the EWPT - a frontier of the high energy particle physics, and it is thus under scrutiny with phenomenological interests. An important feature in the EWPT is that left-handed neutrinos possess a non-trivial collective excitation due to the presence of massive weak bosons. We have taken account of this effect and evaluated the decay rate of the right-handed neutrino, a key quantity in the leptogenesis. Comparing to the case assuming massless weak bosons, the decay rate gets 30% enhancement at around 100 GeV.
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