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arXiv 1310.7488astro-ph.SRastro-ph.HEhep-ph
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高分辨率超新星模型中的Turbulence模式和中微子味跃迁

Turbulence patterns and neutrino flavor transitions in high-resolution supernova models

Enrico Borriello, Sovan Chakraborty, Hans-Thomas Janka, Eligio Lisi, Alessandro Mirizzi

摘要:

在核塌缩超新星(SN)的激波传播过程中,物质湍流会影响中微子味转换几率。这种效应通常是通过在粗糙的球对称物质密度分布上添加参数化的小尺度随机波动(具有任意振幅)来研究的。然而,最近,二维(2D)SN模型已经达到了足够高的空间分辨率,直接跟踪各向异性的密度分布,下到尺度小于典型的中微子振荡长度。在这种情况下,我们分析了一个大的SN物质密度分布在高分辨率的2D模拟中获得的统计特性,专注于反弹后的时间(2秒)适合于研究冲击波对中微子传播的影响小到O(100)公里,并可能低于。我们清楚地发现一个破碎的(Kolmogorov-Kraichnan)幂律结构的印记,一般预期在二维湍流谱。然后,我们计算的味道演变SN中微子沿代表性实现的湍流物质密度分布,并观察到没有或适度阻尼的中微子穿越概率的方式通过冲击波。为了检查在O(100)km以下的尺度上可能未解决的波动的影响,我们还应用了一个随机化程序锚定从模拟计算的功率谱,并找到一致的结果内\pm 1西格玛波动。这些结果表明锚定湍流效应对SN中微子的现实,细粒度的SN模型的重要性。

英文摘要:

During the shock-wave propagation in a core-collapse supernova (SN), matter turbulence may affect neutrino flavor conversion probabilities. Such effects have been usually studied by adding parametrized small-scale random fluctuations (with arbitrary amplitude) on top of coarse, spherically symmetric matter density profiles. Recently, however, two-dimensional (2D) SN models have reached a space resolution high enough to directly trace anisotropic density profiles, down to scales smaller than the typical neutrino oscillation length. In this context, we analyze the statistical properties of a large set of SN matter density profiles obtained in a high-resolution 2D simulation, focusing on a post-bounce time (2 s) suited to study shock-wave effects on neutrino propagation on scales as small as O(100) km and possibly below. We clearly find the imprint of a broken (Kolmogorov-Kraichnan) power-law structure, as generically expected in 2D turbulence spectra. We then compute the flavor evolution of SN neutrinos along representative realizations of the turbulent matter density profiles, and observe no or modest damping of the neutrino crossing probabilities on their way through the shock wave. In order to check the effect of possibly unresolved fluctuations at scales below O(100) km, we also apply a randomization procedure anchored to the power spectrum calculated from the simulation, and find consistent results within \pm 1 sigma fluctuations. These results show the importance of anchoring turbulence effects on SN neutrinos to realistic, fine-grained SN models.

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