Neutrino oscillations in the early universe: how call large lepton asymmetry be generated?

被引:39
作者
Dolgov, AD
Hansen, SH
Pastor, S
Semikoz, DV
机构
[1] Teoret Astrofys Ctr, DK-2100 Copenhagen, Denmark
[2] ITEP, Moscow 113259, Russia
[3] SISSA, ISAS, I-34013 Trieste, Italy
[4] Ist Nazl Fis Nucl, Sez Trieste, I-34013 Trieste, Italy
[5] Max Planck Inst Phys & Astrophys, Werner Heisenberg Inst Phys, D-80805 Munich, Germany
[6] Russian Acad Sci, Inst Nucl Res, Moscow 117312, Russia
关键词
D O I
10.1016/S0927-6505(00)00111-0
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
The lepton asymmetry that could be generated in the early universe through oscillations of active to sterile neutrinos is calculated (almost) analytically for small mixing angles, sin 2 theta < 10(-2). It is shown that for a mass squared difference, delta m(2) = -1 eV(2) it may rise at most by six orders of magnitude from the initial "normal" value similar to 10(-10) as the back-reaction from the refraction index terminates this rise while the asymmetry is still small. Only for very large mass differences, \delta m(2)\ similar to 10(9) eV(2), the lepton asymmetry could reach a significant magnitude exceeding 0.1. (C) 2000 Elsevier Science B.V. All rights reserved.
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收藏
页码:79 / 90
页数:12
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