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arXiv 0709.0413hep-ph
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中微子质量在轻子生成中的作用

Effects of Lightest Neutrino Mass in Leptogenesis

E. Molinaro, S. T. Petcov, T. Shindou, Y. Takanishi

摘要:

当宇宙的重子不对称性的产生所必需的CP破坏完全是由于中微子混合矩阵U中的狄拉克和/或马约拉纳相时,研究了最轻中微子质量在“有味道”的leptogenesis中的影响。考虑了三个重右手Majorana中微子具有分级谱的I型跷跷板情形。中微子汤川耦合矩阵的“正交”参数化,其中涉及一个复杂的正交矩阵R,被采用。给出了轻中微子正序和逆序质谱的结果。特别指出,如果矩阵R是实数且CP守恒的,并且在倒置分级谱的情况下最轻的中微子质量m_3位于区间5 \times 10^{-4} eV < m_3 < 7 \times 10^{-3} eV,则预测的重子不对称性可以比对应于可忽略的m_3 \sim 0的不对称性大1/100。因此,即使R是真实的,并且在稀薄成因中CP破坏的唯一来源是U中的Majorana和/或Dirac相,我们也可以成功地进行5 \times 10 ^{-6} eV < m_3 < 5 \times 10^{-2} eV的热稀薄成因。

英文摘要:

The effects of the lightest neutrino mass in ``flavoured'' leptogenesis are investigated in the case when the CP-violation necessary for the generation of the baryon asymmetry of the Universe is due exclusively to the Dirac and/or Majorana phases in the neutrino mixing matrix U. The type I see-saw scenario with three heavy right-handed Majorana neutrinos having hierarchical spectrum is considered. The ``orthogonal'' parametrisation of the matrix of neutrino Yukawa couplings, which involves a complex orthogonal matrix R, is employed. Results for light neutrino mass spectrum with normal and inverted ordering (hierarchy) are obtained. It is shown, in particular, that if the matrix R is real and CP-conserving and the lightest neutrino mass m_3 in the case of inverted hierarchical spectrum lies the interval 5 \times 10^{-4} eV < m_3 < 7 \times 10^{-3} eV, the predicted baryon asymmetry can be larger by a factor of \sim 100 than the asymmetry corresponding to negligible m_3 \cong 0. As consequence, we can have successful thermal leptogenesis for 5 \times 10^{-6} eV < m_3 < 5 \times 10^{-2} eV even if R is real and the only source of CP-violation in leptogenesis is the Majorana and/or Dirac phase(s) in U.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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