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arXiv 0904.3046hep-phastro-ph.CO
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半相对论性文物的热衰减

The Thermal Abundance of Semi-Relativistic Relics

Manuel Drees, Mitsuru Kakizaki, Suchita Kulkarni

摘要:

玻尔兹曼方程的近似解析解的粒子,无论是极端的相对论性或非相对论性时,他们从热浴解耦是公认的。然而,还没有已知的半相对论性退耦粒子的残余密度的解析公式。本文提出了一种新的湮没截面热平均值的计算方法,并找到了一种计算其残余密度的半解析方法。作为例子,我们考虑马约拉纳和狄拉克型中微子。我们表明,这样的半相对论遗迹不能很好的冷暗物质的候选人。然而,亚稳定的半相对论性遗迹的晚期衰变可能释放了大量的熵,从而稀释了其他不需要的遗迹的密度。

英文摘要:

Approximate analytical solutions of the Boltzmann equation for particles that are either extremely relativistic or non-relativistic when they decouple from the thermal bath are well established. However, no analytical formula for the relic density of particles that are semi-relativistic at decoupling is yet known. We propose a new ansatz for the thermal average of the annihilation cross sections for such particles, and find a semi-analytical treatment for calculating their relic densities. As examples, we consider Majorana- and Dirac-type neutrinos. We show that such semi-relativistic relics cannot be good cold Dark Matter candidates. However, late decays of meta-stable semi-relativistic relics might have released a large amount of entropy, thereby diluting the density of other, unwanted relics.

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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