Dynamical axion misalignment with small instantons
Dynamical axion misalignment with small instantons
复制标题
小瞬子的动态轴子失准
DOI：
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复制
发表时间：
2019
影响因子：
5.4
通讯作者：
JiJi Fan
中科院分区：
文献类型：
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作者：
Manuel A. Buen;JiJi Fan
我们提出了一种新的机制来松弛QCD轴子的初始失准角，提高轴子衰变常数的宇宙学界。在暴胀期间，QCD轴子接收到来自小紫外瞬子的贡献，这将其质量提高到暴胀的哈勃尺度。这使得轴子在早期就开始降低它的势。在这种情况下，夸克的标准模型汤川耦合是动态的，在暴胀时期是一阶的，一旦暴胀结束就降低到标准模型的值。这意味着在暴胀之后，小瞬子的贡献被抑制，轴子势从通常的IR瞬子降低到标准的轴子势。结果，当轴子在膨胀后再次开始振荡时，由于膨胀期间的动力学，初始失准角被抑制。虽然动力学轴子错位的一般思想已经在文献中讨论过，我们详细介绍了在膨胀期间和之后的轴子势的最小值之间的不匹配的主要瓶颈，以及如何在我们的情况下通过Froggatt-Nielsen机制规避。考虑到所有的限制，我们发现，轴子衰变常数可以提高到大统一理论的规模，1015 GeV，在我们的情况下。
We present a new mechanism to relax the initial misalignment angle of the QCD axion and raise the cosmological bound on the axion decay constant. The QCD axion receives a contribution from small UV instantons during inflation, which raises its mass to the inflationary Hubble scale. This makes the axion start rolling down its potential early on. In the scenario, the standard model Yukawa couplings of quarks are dynamical, being of order one during the inflationary era and reducing to their standard model values once it ends. This means that after inflation the contribution of the small instantons is suppressed, and the axion potential reduces to the standard one from the usual IR instantons. As a result, when the axion starts to oscillate again after inflation, the initial misalignment angle is suppressed due to the dynamics during inflation. While the general idea of dynamical axion misalignment has been discussed in the literature before, we present in detail the major bottleneck on the mismatching between the minima of the axion potentials during and after inflation, and how it is circumvented in our scenario via the Froggatt-Nielsen mechanism. Taking into account of all the constraints, we find that the axion decay constant could be raised to the GUT scale, 1015 GeV, in our scenario.
影响因子：
12.5
作者：
Budker, Dmitry;Graham, Peter W.;Sushkov, Alexander O.
通讯作者：
Sushkov, Alexander O.
颜色统一动力轴
DOI：
10.1140/epjc/s10052-018-6396-6
发表时间：
2018
期刊：
The European Physical Journal C
影响因子：
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作者：
Gaillard, M. K.;Gavela, M. B.;Houtz, R.;Quilez, P.;del Rey, R.
通讯作者：
del Rey, R.