论文标题
不可还原轴心背景
The Irreducible Axion Background
论文作者
论文摘要
搜索暗物质腐烂到光子的寿命将其寿命限制为比宇宙年龄大的数量级。必然的陈述是，在宇宙时间尺度上腐烂到光子的任何粒子的丰度被限制在比冷的深色 - 强度密度小得多。我们表明，$ \ textit {nordreducible} $冻结对轴的遗物密度的贡献违反了参数空间的很大一部分。这使我们能够在质量范围$ 100 \ rm \; ev -100 \的轴上设置严格的约束。 mev $。 $ 10 \ rm \; kev $我们对光轴的约束是$ g_ {aγγ} \ Lessim 8.1 \ times 10^{ - 14}〜{\ rm gev}^{ - 1} $，几乎比使用水平分支星星建立的界限要强三个数量级； at $100~{\rm keV}$ our constraint on a photophobic axion coupled to electrons is $g_{aee} \lesssim 8.0 \times 10^{-15}$, almost four orders of magnitude stronger than present results.尽管我们专注于轴心，但我们的论点更为笼统，可以扩展到例如无菌中微子。
Searches for dark matter decaying into photons constrain its lifetime to be many orders of magnitude larger than the age of the Universe. A corollary statement is that the abundance of any particle that can decay into photons over cosmological timescales is constrained to be much smaller than the cold dark-matter density. We show that an $\textit{irreducible}$ freeze-in contribution to the relic density of axions is in violation of that statement in a large portion of the parameter space. This allows us to set stringent constraints on axions in the mass range $100\rm \;eV - 100\; MeV$. At $10\rm \; keV$ our constraint on a photophilic axion is $g_{aγγ} \lesssim 8.1 \times 10^{-14}~{\rm GeV}^{-1}$, almost three orders of magnitude stronger than the bounds established using horizontal branch stars; at $100~{\rm keV}$ our constraint on a photophobic axion coupled to electrons is $g_{aee} \lesssim 8.0 \times 10^{-15}$, almost four orders of magnitude stronger than present results. Although we focus on axions, our argument is more general and can be extended to, for instance, sterile neutrinos.
