Production of dark matter axions from collapse of string-wall systems
Production of dark matter axions from collapse of string-wall systems
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DOI：
10.1103/physrevd.85.105020
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发表时间：
2012-02
影响因子：
5
通讯作者：
T. Hiramatsu;M. Kawasaki;K. Saikawa;Toyokazu Sekiguchi
中科院分区：
文献类型：
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作者：
T. Hiramatsu;M. Kawasaki;K. Saikawa;Toyokazu Sekiguchi
我们分析了磁畴壁塌陷辐射出的轴子的光谱，这在文献中受到的关注较少。通过进行场论晶格模拟来研究与轴子模型相关的拓扑缺陷的演化。我们模拟了缺陷演化的整个过程，包括全局弦的形成、磁畴壁的形成以及壁张力导致的缺陷的湮灭。辐射轴子的频谱在低频处有一个峰值，这意味着由磁畴壁塌陷产生的轴子不是高度相对论性的。我们重新审视冷暗物质轴子的遗迹丰度，发现缺陷衰变的贡献可以与弦的贡献相媲美。这个结果导致轴子衰变常数的上限更严格。
We analyze the spectrum of axions radiated from collapse of domain walls, which have received less attention in the literature. The evolution of topological defects related to the axion models is investigated by performing field-theoretic lattice simulations. We simulate the whole process of evolution of the defects, including the formation of global strings, the formation of domain walls and the annihilation of the defects due to the tension of walls. The spectrum of radiated axions has a peak at the low frequency, which implies that axions produced by the collapse of domain walls are not highly relativistic. We revisit the relic abundance of cold dark matter axions and find that the contribution from the decay of defects can be comparable with the contribution from strings. This result leads to a more severe upper bound on the axion decay constant.