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

Title: kination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 is 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-张量早期大爆炸核合成宇宙学对惰性中微子非共振产生的影响。我们表明，如果惰性中微子产生率的峰值发生在非标准宇宙学阶段，与标准宇宙学预期的数量相比，惰性中微子的遗迹数量密度会减少。因此，从惰性中微子遗迹能量密度得出的活性-惰性中微子混合当前限制可能会大大放松。特别是，我们表明，可以解释短基线中微子实验中发现的异常的惰性中微子，在标量-张量或低再加热温度的早期大爆炸核合成宇宙学中，与最近联合Planck对它们对宇宙能量密度贡献的上限是兼容的。