2006 Fiscal Year Final Research Report Summary
Study of production mechanism of universe's baryon number and neutrino masses
| Project/Area Number |
16540230
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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 |
Particle/Nuclear/Cosmic ray/Astro physics
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| Research Institution | The University of Tokyo |
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Principal Investigator |
YANAGIDA Tsutomu The University of Tokyo, Graduate School of Science, Professor, 大学院理学系研究科, 教授 (10125677)
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| Project Period (FY) |
2004 – 2006
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| Keywords | neutrino / universe's baryon number / inflation universe / supersymmetry / supergravity / gravitino |
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| Research Abstract |
The seesaw mechanism that explains naturally the observed small neutrino masses predicts heavy Majorana neutrinos. It is known that the decay of the heavy Majorana neutrinos produce lepton asymmetry which is converted to the baryon asymmetry. Thus, one may explain the baryon-number asymmetry in the universe by the decay of the Majorana neutrino decay. In the present project we have shown that it is indeed the case and that the observed neutrino masses are very consistent with the mechanism of the above baryogenesis. In particular, we have considered inflation models based on supergravity and found that most of the inflation models produce too much gravitinos if the above baryogenesis takes place. We have also found that gauge and anomaly mediation scenarios for supersymmetry breaking do not suffer from this problem. Therefore the present baryogenesis scenario based on the decay of heavy Majorana neutrinos predicts certain spectra of super-particles at low energies, which will be tested at the near future collider experiments such as LHC.
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Research Products
(38 results)
