Title: Effects of kination and scalar-tensor cosmologies on sterile neutrinos Show Chinese title

Title: 动力学和标量-张量宇宙学对惰性中微子的影响

Abstract: We study the effects of kination and scalar-tensor pre-Big Bang Nucleosynthesis cosmologies on the non-resonant production of sterile neutrinos. We show that if the peak of the production rate of sterile neutrinos occurs during the non-standard cosmological phase, the relic number density of sterile neutrinos could be reduced with respect to the number expected in the standard cosmology. Consequently, current bounds on active-sterile neutrino mixing derived from the relic energy density of sterile neutrinos could be greatly relaxed. In particular, we show that the sterile neutrinos which could explain the anomalies found in short-baseline neutrino experiments are compatible with recent joint Planck upper limits on their contribution to the energy density of the Universe in a scalar-tensor or a low-reheating temperature pre-Big Bang Nucleosynthesis cosmology. Show Chinese abstract

Abstract: 我们研究了kination和标量-张量先大爆炸核合成宇宙学对无共振产生惰性中微子的影响。我们表明，如果惰性中微子的产生率峰值出现在非标准宇宙学阶段，则与标准宇宙学预期相比，惰性中微子的遗迹数密度可能会降低。因此，由惰性中微子遗迹能量密度得出的当前关于活性-惰性中微子混合的限制可能大大放宽。特别是，我们表明能够解释短基线中微子实验中发现的异常的惰性中微子与最近联合Planck上限兼容，这些上限是在标量-张量或低再加热温度先大爆炸核合成宇宙学中对宇宙能量密度的贡献。