论文标题
QCD轴子和重力波在纳米级结果下
The QCD Axion and Gravitational Waves in light of NANOGrav results
论文作者
论文摘要
北美纳米赫兹引力波（Nanograv）协作最近报告了有力的证据证明了影响脉冲星时间差残差12.5年数据集的随机过程。我们表明，可以根据早期宇宙中轴心串网络发出的随机引力背景来解释信号。 Peccei-Quinn对称性的自发断裂起源于轴子弦网和QCD轴，即模型中的暗物质粒子。我们探索了一个非标准的宇宙学模型，该模型由异国情调的标量场$ ϕ $驱动，该模型在自我相互作用潜力的影响下演变而来；在修改后的宇宙学期间，轴支球场开始振荡，并提供了观察到的暗物质。对于状态$ W_D <1/3 $的方程式，QCD轴质量比标准宇宙学中的预期小，并且轴支字符串的GW频谱较大。我们评估了模型的参数空间，该参数空间与纳米格拉夫 - $ 12.5 \，$ yr检测一致，可以在95 \％限制以内通过QCD轴上场在类似灰尘的情况下演变，以及在COSMOLOGY中以$ W_D = 0 <0 $ $ W_D <0 $。
The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration has recently reported strong evidence for a stochastic process affecting the 12.5 yr dataset of pulsar timing residuals. We show that the signal can be interpreted in terms of a stochastic gravitational wave background emitted from a network of axionic strings in the early Universe. The spontaneous breaking of the Peccei-Quinn symmetry originate the axionic string network and the QCD axion, the dark matter particle in the model. We explore a non-standard cosmological model driven by an exotic scalar field $ϕ$ which evolves under the influence of a self-interacting potential; the axion field starts to oscillate during the modified cosmology, and provides the dark matter observed. For an equation of state $w_ϕ< 1/3$, the QCD axion mass is smaller than expected in the standard cosmology and the GW spectrum from axionic strings is larger. We assess the parameter space of the model which is consistent with the NANOGrav-$12.5\,$yr detection, which can be explained within 95\% limit by a QCD axion field evolving in a dust-like scenario, as well as within 68\% limit in a cosmology with $w_ϕ< 0$.
