Fast-pairwise Collective Neutrino Oscillations Associated with Asymmetric Neutrino Emissions in Core-collapse Supernovae
Fast-pairwise Collective Neutrino Oscillations Associated with Asymmetric Neutrino Emissions in Core-collapse Supernovae
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DOI：
10.3847/1538-4357/ab4cf2
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发表时间：
2019-10
期刊：
影响因子：
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通讯作者：
H. Nagakura;Taiki Morinaga;Chinami Kato;S. Yamada
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文献类型：
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作者：
H. Nagakura;Taiki Morinaga;Chinami Kato;S. Yamada
基于我们最新的轴对称核心坍缩超新星（CCSN）模拟结果，我们提出了快速成对中微子风味转换的线性稳定性分析。在CCSN模拟中，电子型中微子（νe）及其反粒子（νe和反粒子的不对称性相互反相关）的相干非对称中微子发射几乎与非球面激波膨胀的开始同时发生。我们发现不对称中微子发射在快速风味转化的发生中起着至关重要的作用。线性分析表明，激波前后流动均存在不稳定模态；对于后者，它们只出现在高排放的半球（激波膨胀更强的同一个半球）。通过对动量空间中中微子的角分布的仔细观察，深入分析了电子-轻子数交叉的特征。ELN交叉以多种方式发生，其性质与半径有关：在中子星附近，νe在正向（反向）方向上优于νe ()；在较大的半径下，ELN的交叉则以相反的方式发生。我们还发现，非径向ELN交叉发生在无ELN交叉和径向ELN交叉的交界处，这是真正的多维输运效应。我们的研究结果表明，集体中微子振荡可能在CCSNe中更常见，并建议CCSN社区在CCSNe建模中需要自我一致地适应这些振荡。
We present a linear stability analysis of the fast-pairwise neutrino flavor conversion based on a result of our latest axisymmetric core-collapse supernova (CCSN) simulation with full Boltzmann neutrino transport. In the CCSN simulation, coherent asymmetric neutrino emissions of electron-type neutrinos (νe) and their antiparticles ( ), in which the asymmetries of νe and are anticorrelated with each other, occur at almost the same time as the onset of aspherical shock expansion. We find that the asymmetric neutrino emissions play a crucial role on occurrences of fast flavor conversions. The linear analysis shows that unstable modes appear in both pre- and post-shock flows; for the latter, they appear only in the hemisphere of higher emissions (the same hemisphere with stronger shock expansion). We analyze the characteristics of electron–lepton number (ELN) crossing in depth by closely inspecting the angular distributions of neutrinos in momentum space. The ELN crossing happens in various ways, and the property depends on the radius: in the vicinity of neutron star, (νe) dominates over νe ( ) in the forward (backward) direction; at the larger radius, the ELN crossing occurs in the opposite way. We also find that the non-radial ELN crossing occurs at the boundary between no ELN crossing and the radial one, which is an effect of genuine multi-dimensional transport. Our findings indicate that the collective neutrino oscillation may occur more commonly in CCSNe and suggest that the CCSN community needs to accommodate these oscillations self-consistently in the modeling of CCSNe.