论文标题
peccei-quinn对称破坏对QCD轴线暗物质的宇宙学影响
Cosmological effects of Peccei-Quinn symmetry breaking on QCD axion dark matter
论文作者
论文摘要
我们研究了明确的peccei-quinn破裂对QCD轴线暗物质的宇宙学影响。我们发现，即使对于满足中子电偶极子测量值的实验结合的微小的peccei-quinn破裂，轴心的丰度也会显着下降或显着增加。如果轴轴首次开始在错误的真空周围振荡，并且如果它被困在那里，直到由于非扰动QCD效应而虚假真空消失，则其丰度大大增加，并且与衰减常数$ f_a $无关，正如[JHEP 06（2016）150]中首先指出的。因此，即使由于出色的冷却参数，衰减常数接近下限，诱捕机制产生的轴法也可以解释暗物质。另一方面，如果轴轴开始在接近低能真空的潜在最小值上振荡，则由于绝热抑制机制，其丰度大大降低。这使轴心窗口的上限放松到$ f_a $的大值。我们还讨论了轴基的等化扰动如何受Peccei-Quinn破坏术语的影响，并表明在这两个制度中都可以抑制它。特别是，与传统场景相比，$ f_a \ sillsim 10^{\ rm gev} $的许多大幅度的幅度与通货膨胀量表上的束缚放松。
We study cosmological effects of explicit Peccei-Quinn breaking on the QCD axion dark matter. We find that the axion abundance decreases or increases significantly depending on the initial position, even for a tiny Peccei-Quinn breaking that satisfies the experimental bound of the neutron electric dipole measurements. If the axion first starts to oscillate around a wrong vacuum and if it gets trapped there until the false vacuum disappears due to non-perturbative QCD effects, its abundance increases significantly and is independent of the decay constant $f_a$, as first pointed out in [JHEP 06 (2016) 150]. Thus, the axion produced by the trapping mechanism can explain dark matter even when the decay constant is close to the lower limit due to stellar cooling arguments. On the other hand, if the axion starts to oscillate about a potential minimum close to the low-energy vacuum, its abundance is significantly reduced because of the adiabatic suppression mechanism. This relaxes the upper limit of the axion window to large values of $f_a$. We also discuss how the axionic isocurvature perturbation is affected by the Peccei-Quinn breaking term, and show that it can be suppressed in both regimes. In particular, the isocurvature bound on the inflation scale is relaxed by many orders of magnitudes for $f_a \lesssim 10^{11}{\rm GeV}$ compared to the conventional scenario.
