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arXiv 1706.03360hep-ph
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超新星中微子的快速味转换:通过色散关系分类不稳定性

Fast flavor conversions of supernova neutrinos: Classifying instabilities via dispersion relations

Francesco Capozzi, Basudeb Dasgupta, Eligio Lisi, Antonio Marrone, Alessandro Mirizzi

摘要:

超新星中微子可以表现出丰富多样的味道转换机制。特别是,它们可以在核心上方几乎立即经历“快速”自诱导的风味转化。最近,一种新的方法已被提出来调查这些现象,在色散关系的复频率和波数($ω$,$k$)的平均场的$ν_eν_x$味相干的扰动。我们讨论了一个系统的方法,这种不稳定性,最初开发的背景下,等离子体物理,并根据系统的格林函数的时间渐近行为。不稳定性通常出现在复杂的$ω$中,并且可以进一步表征为对流(移动速度快于扩散速度)和绝对(局部增长),这取决于$k$依赖的特征。当$k$(但不是$ω$)是复数时,稳定的情况出现,导致空间中的扰动阻尼,或者当$ω$和$k$都是实数时,对应于完全稳定。不稳定和稳定模式的分析分类导致不仅定性的见解,他们的功能,但也定量预测的增长率的不稳定性。在一个简单的双束相互作用中微子模型中讨论了有代表性的数值解。作为一个应用,我们认为,超新星和双星中子星合并表现出“交叉”的电子轻子数将导致绝对不稳定的中微子气体的味道含量。

英文摘要:

Supernova neutrinos can exhibit a rich variety of flavor conversion mechanisms. In particular, they can experience "fast" self-induced flavor conversions almost immediately above the core. Very recently, a novel method has been proposed to investigate these phenomena, in terms of the dispersion relation for the complex frequency and wave number ($ω$,$k$) of disturbances in the mean field of the $ν_eν_x$ flavor coherence. We discuss a systematic approach to such instabilities, originally developed in the context of plasma physics, and based of the time-asymptotic behavior of the Green's function of the system. Instabilities are typically seen to emerge for complex $ω$, and can be further characterized as convective (moving away faster than they spread) and absolute (growing locally), depending on $k$-dependent features. Stable cases emerge when $k$ (but not $ω$) is complex, leading to disturbances damped in space, or when both $ω$ and $k$ are real, corresponding to complete stability. The analytical classification of both unstable and stable modes leads not only to qualitative insights about their features but also to quantitative predictions about the growth rates of instabilities. Representative numerical solutions are discussed in a simple two-beam model of interacting neutrinos. As an application, we argue that supernova and binary neutron star mergers exhibiting a "crossing" in the electron lepton number would lead to an absolute instability in the flavor content of the neutrino gas.

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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