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arXiv 2210.01148hep-phastro-ph.CO
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随机Relaxion

The Stochastic Relaxion

Aleksandr Chatrchyan, Géraldine Servant

AI总结:

本文研究了在暴胀期间经历大幅波动的 relaxion 的随机动力学,通过 Fokker-Planck 形式推导出新的停止条件,发现随机游走阻止 relaxion 被困于首个极小值,从而消除了“失控 relaxion”威胁,恢复了大部分参数空间并开启了新的唯象学机会。

摘要:

我们重新审视了由 Graham, Kaplan 和 Rajendran 提出的电弱能标宇宙学弛豫的原始方案,其中 Higgs 质量在暴胀期间由 axion 场(即 relaxion)进行扫描。我们研究了 relaxion 在暴胀期间经历大幅波动的情形。relaxion 的随机动力学通过 Fokker-Planck 形式来描述。我们推导出了 relaxion 的新停止条件,考虑了其势能相邻局部极小值之间的跃迁。即使在“经典胜过量子”的区域内,relaxion 的波动也具有重要影响。我们确定,对于暴胀期间较大的 Hubble 参数,随机游走阻止了 relaxion 被困在第一个极小值处。relaxion 停止在更远的地方,那里的势能较不浅。有趣的是,这基本上消除了有限密度效应带来的“失控 relaxion”威胁,恢复了 relaxion 大部分参数空间。我们还探索了“量子胜过经典”的区域,开启了广阔的新参数空间区域。我们研究了 QCD 和非 QCD relaxion 的后果。relaxion 由于在其局部极小值附近的波动而产生的失准开启了新的唯象学机会。

英文摘要:

We revisit the original proposal of cosmological relaxation of the electroweak scale by Graham, Kaplan and Rajendran in which the Higgs mass is scanned during inflation by an axion field, the relaxion. We investigate the regime where the relaxion is subject to large fluctuations during inflation. The stochastic dynamics of the relaxion is described by means of the Fokker-Planck formalism. We derive a new stopping condition for the relaxion taking into account transitions between the neighboring local minima of its potential. Relaxion fluctuations have important consequences even in the "classical-beats-quantum" regime. We determine that for a large Hubble parameter during inflation, the random walk prevents the relaxion from getting trapped at the first minimum. The relaxion stops much further away, where the potential is less shallow. Interestingly, this essentially jeopardises the "runaway relaxion" threat from finite-density effects, restoring most of the relaxion parameter space. We also explore the "quantum-beats-classical" regime, opening large new regions of parameter space. We investigate the consequences for both the QCD and the non-QCD relaxion. The misalignment of the relaxion due to fluctuations around its local minimum opens new phenomenological opportunities.

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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