Cosmological Constraints on Late-time Entropy Production
Cosmological Constraints on Late-time Entropy Production
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后期熵产生的宇宙学约束
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
N. Sugiyama
中科院分区：
文献类型：
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作者：
M. Kawasaki;K. Kohri;N. Sugiyama
我们研究了非相对论性大质量粒子衰变引起的晚期熵产生的宇宙学效应。利用玻尔兹曼方程较好地求解了中微子熵产生后的热化过程。如果一个大的熵产生发生在晚时间t$simeq $1秒，它被发现，很大一部分中微子不能热化。这一事实放松了大爆炸核合成对再加热温度T_R的严格限制，T_R可以低至0.5MeV。并讨论了对大尺度结构形成和宇宙微波背景各向异性的影响。
We investigate cosmological effects concerning the late-time entropy production due to the decay of non-relativistic massive particles. The thermalization process of neutrinos after the entropy production is properly solved by using the Boltzmann equation. If a large entropy production takes place at late time t$simeq$ 1 sec, it is found that a large fraction of neutrinos cannot be thermalized. This fact loosens the tight constraint on the reheating temperature T_R from the big bang nucleosynthesis and T_R could be as low as 0.5 MeV. The influence on the large scale structure formation and cosmic microwave background anisotropies is also discussed.