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arXiv 2108.08359hep-phastro-ph.COgr-qc
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用引力波谱探测轻子成因和前BBN宇宙

Probing Leptogenesis and Pre-BBN Universe with Gravitational Waves Spectral Shapes

Rome Samanta, Satyabrata Datta

摘要:

在频率-振幅平面上,宇宙弦的引力波(GW)在高频率处表现出平坦的平台,这是由于标准辐射主导的后暴胀时期的弦环动力学。如果在大爆炸核合成(BBN)之前的原始黑暗时代表现出非标准的宇宙历史,那么在超过转折点频率$f_*$之后,光谱可能会显示出突然的上升或下降趋势。我们认为,这样的光谱中断后,随着GW振幅的上升,这是一个后暴胀状态方程($ω>1/3$)比辐射($ω=1/3$)更硬的结果,也可能是一个强烈的暗示,在中微子质量的跷跷板模型leptogenesis。通过规范$U(1)$对称破缺动力学产生右手中微子质量,导致宇宙弦网络的形成,并发射随机引力波。由$\partial_μR j^μ$形式的算子引起的轻子流的引力相互作用--它可以在跷跷板模型中通过RH中微子调解在两圈水平上产生,自然地寻求更刚性的状态方程来有效地产生与$1-3ω$成比例的重子不对称性。我们讨论了如何GWs与中微子少的双β衰变信号补充合理的强振幅可以探测到最近的辐射优势和最轻的RH中微子质量在中间尺度的开始。

英文摘要:

On the frequency-amplitude plane, Gravitational Waves (GWs) from cosmic strings show a flat plateau at higher frequencies due to the string loop dynamics in standard radiation dominated post-inflationary epoch. The spectrum may show an abrupt upward or a downward trend beyond a turning point frequency $f_*$, if the primordial dark age prior to the Big Bang Nucleosynthesis (BBN), exhibits non-standard cosmic histories. We argue that such a spectral break followed by a rising GW amplitude which is a consequence of a post-inflationary equation of state ($ω>1/3$) stiffer than the radiation ($ω=1/3$), could also be a strong hint of a leptogenesis in the seesaw model of neutrino masses. Dynamical generation of the right handed (RH) neutrino masses by a gauged $U(1)$ symmetry breaking leads to the formation of a network of cosmic strings which emits stochastic GWs. A gravitational interaction of the lepton current by an operator of the form $\partial_μR j^μ$--which can be generated in the seesaw model at the two-loop level through RH neutrino mediation, naturally seeks a stiffer equation of state to efficiently produce baryon asymmetry proportional to $1-3ω$. We discuss how GWs with reasonably strong amplitudes complemented by a neutrino-less double beta decay signal could probe the onset of the most recent radiation domination and lightest RH neutrino mass at the intermediate scales.

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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