We investigate the impact of the nonzero neutrino splitting and elastic neutrino-nucleon collisions on fast neutrino oscillations. Our calculations confirm that a small neutrino mass splitting and the neutrino mass hierarchy have very little effect on fast oscillation waves. We also demonstrate explicitly that fast oscillations remain largely unaffected for the time/distance scales that are much smaller than the neutrino mean free path but are damped on larger scales. This damping originates from both the direct modification of the dispersion relation of the oscillation waves in the neutrino medium and the flattening of the neutrino angular distributions over time. Our work suggests that fast neutrino oscillation waves produced near the neutrino sphere can propagate essentially unimpeded which may have ramifications in various aspects of the supernova physics.

中文翻译：

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在稠密的中微子介质中具有碰撞的快速风味振荡

我们研究了非零中微子分裂和弹性中微子-核子碰撞对快速中微子振荡的影响。我们的计算证实，较小的中微子质量分裂和中微子质量等级对快速振荡波影响很小。我们还明确表明，对于比中微子平均自由程小得多但在较大尺度上受到阻尼的时间/距离尺度，快速振荡仍然在很大程度上不受影响。这种衰减既源于中微子介质中振荡波的色散关系的直接改变，也源于中微子角分布随时间的变平。