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arXiv 1801.07409hep-phastro-ph.CO
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轴子衰变常数$F_a$的宇宙学允许区域

Cosmologically allowed regions for the axion decay constant $F_a$

Masahiro Kawasaki, Eisuke Sonomoto, Tsutomu T. Yanagida

摘要:

如果Peccei-Quinn对称性在暴胀过程中已经被破坏,那么轴子的衰变常数$F_a$可以在$10^{11}$ GeV到$10^{18}$ GeV之间的一个很宽的区域内,因为轴子是主导暗物质。然而,在这种情况下,轴子引起了严重的宇宙学问题,等曲率扰动问题,这严重限制了膨胀期间的哈勃参数。当Peccei-Quinn标量场在暴胀过程中取较大值$\sim M_{p}$(普朗克尺度)时,该约束被放松.本文指出,当Peccei-Quinn标量场在暴胀过程中取$\sim M_{p}$时,对于给定的张量标量比$r$,衰减常数$F_a$的允许区域缩小到一个相当窄的区域.例如,如果在将来的测量中将$r$的比值确定为$r \gtrsim 10^{-3}$,则我们可以预测畴壁数$N_\text{DW}=6$的$F_a \simeq (0.1-1.4)\times 10^{12}$ GeV。

英文摘要:

If the Peccei-Quinn symmetry is already broken during inflation, the decay constant $F_a$ of the axion can be in a wide region from $10^{11}$ GeV to $10^{18}$ GeV for the axion being the dominant dark matter. In this case, however, the axion causes the serious cosmological problem, isocurvature perturbation problem, which severely constrains the Hubble parameter during inflation. The constraint is relaxed when Peccei-Quinn scalar field takes a large value $\sim M_{p}$ (Planck scale) during inflation. In this letter, we point out that the allowed region of the decay constant $F_a$ is reduced to a rather narrow region for a given tensor-to-scalar ratio $r$ when Peccei-Quinn scalar field takes $\sim M_{p}$ during inflation. For example, if the ratio $r$ is determined as $r \gtrsim 10^{-3}$ in future measurements, we can predict $F_a \simeq (0.1-1.4)\times 10^{12}$ GeV for domain wall number $N_\text{DW}=6$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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