Abundance of cosmological relics in low-temperature scenarios
Abundance of cosmological relics in low-temperature scenarios
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DOI：
10.1103/physrevd.73.123502
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发表时间：
2006-03
影响因子：
5
通讯作者：
M. Drees;Hoernisa Iminniyaz;M. Kakizaki
中科院分区：
文献类型：
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作者：
M. Drees;Hoernisa Iminniyaz;M. Kakizaki
我们研究了非相对论性长寿命或稳定粒子\chi在宇宙学场景中的残余密度n\chi，其中温度T太低，\chi无法达到完全的化学平衡。一个较重的粒子衰变到\chi的情况下也进行了研究。我们得到的近似解的n_\chi（T），准确地再现数值结果时，完全热平衡没有实现。如果达到完全平衡，我们的模型就不能正确地再现chi数密度与温度的关系。然而，它确实给出了正确的最终残体密度，对于所有横截面和初始温度，精度约为3%或更高。
We investigate the relic density n_\chi of non-relativistic long-lived or stable particles \chi in cosmological scenarios in which the temperature T is too low for \chi to achieve full chemical equilibrium. The case with a heavier particle decaying into \chi is also investigated. We derive approximate solutions for n_\chi(T) which accurately reproduce numerical results when full thermal equilibrium is not achieved. If full equilibrium is reached, our ansatz no longer reproduces the correct temperature dependence of the \chi number density. However, it does give the correct final relic density, to an accuracy of about 3% or better, for all cross sections and initial temperatures.