论文标题
从深色光子共振到脉冲星观测和有效数量相对论物种的引力波产生的含义
Implications of Gravitational-wave Production from Dark Photon Resonance to Pulsar-timing Observations and Effective Number of Relativistic Species
论文作者
论文摘要
由于共振和速度增强，轴承场的连贯振荡自然会驱动早期宇宙中深色光子颗粒的产生。在此过程中，能量从前者突然转移到后者，从而产生引力波的产生。今天，最终将产生的引力波视为当今的随机背景。我们报告了该生产的分析结果，并将其与Nanograv合作的最新脉冲星定位结果联系起来。我们显示一个可用的参数空间，围绕质量$ m_ϕ \ sim 10^{ - 13} \，{\ rm ev} $和衰减常数$ f_2 \ sim 10^{16} \，{\ rm gev} $，带有$ {\ cal o}（\ cal o}（\ cal o}（1）$的无面值的coupling coupling for我们的机制，以供我们的机制。避免过度主导宇宙的轴轴的机制是该模型的必要组成部分，我们讨论了恢复对称性并在生产后使轴心无质量的可能性。我们还评论了所需有效数量的相对论物种对确定当前哈勃常数的潜在影响。
The coherent oscillation of axionic fields naturally drives copious production of dark photon particles in the early universe, due to resonance and tachyonic enhancement. During the process, energy is abruptly transferred from the former to the latter, sourcing gravitational wave generation. The resulting gravitational waves are eventually to be observed as stochastic background today. We report analytical results of this production and connect them to the recent pulsar-timing results by the NANOGrav collaboration. We show an available parameter space, around the mass $m_ϕ\sim 10^{-13} \, {\rm eV}$ and the decay constant $f_ϕ\sim 10^{16} \, {\rm GeV}$ with a dimensionless coupling of ${\cal O}(1)$, for our mechanism to account for the signal. A mechanism to avoid the axion over-dominating the universe is a necessary ingredient of this model, and we discuss a possibility to recover a symmetry and render the axion massless after the production. We also comment on potential implications of the required effective number of relativistic species to the determination of the present Hubble constant.
