CP Violation and Baryogenesis

Research Project

Project/Area Number	11640254
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	素粒子・核・宇宙線
Research Institution	University of Tokyo
Principal Investigator	ARAFUNE Jiro Institute for Cosmic Ray Research professor, 宇宙線研究所, 教授 (80013415)
Project Period (FY)	1999 – 2000
Project Status	Completed (Fiscal Year 2000)
Budget Amount *help	¥1,900,000 (Direct Cost: ¥1,900,000) Fiscal Year 2000: ¥800,000 (Direct Cost: ¥800,000) Fiscal Year 1999: ¥1,100,000 (Direct Cost: ¥1,100,000)
Keywords	CP / baryon number / F-ball / Q-ball / dark matter / baryon separation / F-Ball / Q-Ball / バリオン数分離 / 安定性
Research Abstract	1. Nontopological Solitons : Baryogenesis scenarios with nontopological solitons have a remarkable possibility to explain both the baryon number and the dark matter. Among them a Q-ball model is a welknown candidate, and another one is a Fermi-ball model. We have examined allowed region of parameters for Q-balls and Fermi-balls by reanalizing the past experiments with some other original purposes. We obtained a strong constraint Q> 10^<22> for Q-balls, while M>10^<29> GeV or M<10^8GeV for Fermi-balls. In case of Fermi-balls we examined the thermal bath effect on the stability of Fermi-ball and found it should be unstable in the thin wall approximation for Debye length shorter than the radius of the Fermi-ball. 2. Fromulation of Weyle spinors for the reflection/transmission There is a possibility that the phase transition from the phase with SU (2) ×U (1) symmetry to the present vacuum was made in two steps first from the symmetric one to another and then from the one to the present one. In such a case we need a careful treatment of Weyle spinors and we formulated in a simple manner.