Self-induced neutrino flavor conversion without flavor mixing
Self-induced neutrino flavor conversion without flavor mixing
复制标题
自诱导中微子风味转换，无需风味混合
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
G. Raffelt
中科院分区：
文献类型：
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作者：
S. Chakraborty;R. Hansen;I. Izaguirre;G. Raffelt
中微子-中微子在稠密介质中的折射可以引起由相互作用的味道振子的集体失控模触发的自感生味道转换。生长速率通常是一个典型的真空振荡频率Δm~2/2e量级。然而，即使在ν电子束与反向运动的ν̄电子束相互作用的简单情况下，并考虑到空间不均匀，最快增长的傅里叶模的增长率也是μ=√2GF nν量级，这是典型的ν-ν相互作用能量。这种生长速度比真空振荡频率大得多，并在更短的时间尺度上产生风味转化。这种“快速风味转换”现象即使在Δm~2/2e消失的情况下也会发生，因此不依赖于能量，而只依赖于角分布。此外，它不需要中微子混合或具有质量，也许除了提供种子扰动外。我们还构造了一个由相交光束组成的简单的均匀例子，并研究了Ray Sawyer提出的一个示意性超新星模型，其中νe和ν̄e以不同的天顶角分布出现，这是快速风味转换的关键因素。在现实的天体物理场景中会发生什么仍有待了解。
Neutrino-neutrino refraction in dense media can cause self-induced flavor conversion triggered by collective run-away modes of the interacting flavor oscillators. The growth rates were usually found to be of order a typical vacuum oscillation frequency Δ m2/2E. However, even in the simple case of a νe beam interacting with an opposite-moving ν̄e beam, and allowing for spatial inhomogeneities, the growth rate of the fastest-growing Fourier mode is of order μ=√2 GF nν, a typical ν–ν interaction energy. This growth rate is much larger than the vacuum oscillation frequency and gives rise to flavor conversion on a much shorter time scale. This phenomenon of “fast flavor conversion” occurs even for vanishing Δ m2/2E and thus does not depend on energy, but only on the angle distributions. Moreover, it does not require neutrinos to mix or to have masses, except perhaps for providing seed disturbances. We also construct a simple homogeneous example consisting of intersecting beams and study a schematic supernova model proposed by Ray Sawyer, where νe and ν̄e emerge with different zenith-angle distributions, the key ingredient for fast flavor conversion. What happens in realistic astrophysical scenarios remains to be understood.