论文标题
打开通货膨胀后QCD轴上的窗口
Opening up a window on the postinflationary QCD axion
论文作者
论文摘要
QCD轴上宇宙学至关重要地取决于QCD轴上是否存在通货膨胀。我们指出，与标准标准相反，即使轴衰变常数为$ f_a $，PECCEI-QUINN（PQ）对称性可能仍然不间断，这比通货膨胀Hubble量表高于通货膨胀率$ h_i $。这是通过PQ标量场的重型升高而实现的，这是由于其领先的与充气量的不可超质量相互作用，该相互作用在高维操作员中编码，该操作员尊重加拉孔的近似移位对称性。该机制为通货膨胀后的QCD轴开辟了一个新窗口，并显着扩大了参数空间，其中QCD轴线暗物质带有$ f_a> h_i $可以与高规模的易位兼容，并且不受轴轴承等外影响的约束。也存在非衍生耦合，它仍然可以控制充气转移对称性，以实现通货膨胀期间PQ场的重升。此外，通过引入早期的物质统治时代，更多的高$ f_a $的参数空间可以产生观察到的DM丰度。
The QCD axion cosmology depends crucially on whether the QCD axion is present during inflation or not. We point out that contrary to the standard criterion, the Peccei-Quinn (PQ) symmetry could remain unbroken during inflation, even when the axion decay constant, $f_a$, is (much) above the inflationary Hubble scale, $H_I$. This is achieved through the heavy-lifting of the PQ scalar field due to its leading non-renormalizable interaction with the inflaton, encoded in a high-dimensional operator which respects the approximate shift symmetry of the inflaton. The mechanism opens up a new window for the post-inflationary QCD axion and significantly enlarges the parameter space, in which the QCD axion dark matter with $f_a > H_I$ could be compatible with high-scale inflation and free from constraints on axion isocurvature perturbations. There also exist non-derivative couplings, which still keep the inflaton shift symmetry breaking under control, to achieve the heavy-lifting of the PQ field during inflation. Additionally, by introducing an early matter domination era, more parameter space of high $f_a$ could yield the observed DM abundance.
