标量诱导引力波作为暗量子色动力学的探针
Scalar induced gravitational waves as probes of dark QCD
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中文总结 AI 辅助
该研究将标量诱导引力波（SIGWs）作为探针，利用暗QCD交叉产生的频移畸变特征，实现对暗禁闭扇区的宇宙学探测，相关分析方法可扩展至其他暗禁闭扇区理论。
中文摘要 AI 辅助
我们研究标量诱导引力波（SIGWs）作为暗量子色动力学（dark QCD）交叉过程的探针。受双希格斯（twin Higgs）和不对称双重子暗物质情景的启发，我们考虑一个禁闭尺度约为标准模型（SM）量子色动力学（QCD）尺度5.5倍的暗QCD扇区。我们构建了SM的有效能量与熵自由度，该SM补充了包含三种轻暗夸克味或全部六种暗夸克味的暗QCD扇区。随后，利用得到的物态参数和声速，求解SM与暗QCD交叉时期的一阶标量扰动和二阶SIGWs。针对单色原初曲率功率谱，我们首先证明，现实的SM热历史会修改SIGW谱，使其不同于理想化的辐射主导情形。接着，我们表明，当增强的标量模式在暗禁闭尺度附近重新进入视界时，暗QCD交叉会产生额外的频移畸变。因此，这一独特特征可作为暗QCD扇区的特征性印记。我们的结果表明，SIGWs为隐藏禁闭扇区提供了互补的宇宙学探针，其特征谱特征相对于SM QCD印记移至更高频率。本工作提出的分析方法也可扩展至其他包含不同暗禁闭扇区的合理理论。
英文摘要
We investigate scalar induced gravitational waves (SIGWs) as probes of a dark QCD crossover. Motivated by twin Higgs and asymmetric twin baryon dark matter scenarios, we consider a dark QCD sector with a confinement scale approximately 5.5 times the Standard Model (SM) QCD scale. We construct the effective energy and entropy degrees of freedom for the SM supplemented by dark QCD sectors containing either three light dark quark flavors or all six dark quark flavors. The resulting equation of state parameter and sound speed are then used to solve the first-order scalar perturbations and the second-order SIGWs through the SM and dark QCD crossover epochs. For a monochromatic primordial curvature power spectrum, we first demonstrate that the realistic SM thermal history modifies the SIGW spectrum relative to the idealized radiation-dominated case. We then show that a dark QCD crossover generates an additional frequency-shifted distortion when the enhanced scalar mode reenters the horizon near the dark confinement scale. This distinctive feature can therefore serve as a characteristic signature of the dark QCD sector. Our results demonstrate that SIGWs provide a complementary cosmological probe of hidden confining sectors, with characteristic spectral features shifted to higher frequencies relative to the SM QCD imprint. The analysis developed in this work can also be extended to other well-motivated theories containing different dark confining sectors.
