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arXiv 2406.09504astro-ph.HEhep-ph
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核坍缩超新星中的中微子量子动力学

Neutrino quantum kinetics in a core-collapse supernova

Shashank Shalgar, Irene Tamborra

AI总结:

本研究通过多角度多能量数值模拟发现,核坍缩超新星核心中的中微子味转换在早期由慢集体不稳定性触发,晚期则因角交叉引发快速转换导致味均分,揭示了超新星核心丰富的唯象学特征。

摘要:

尽管中微子驱动的超新星机制可能与之相关,但我们对超新星核心内中微子味转换的理解仍处于初步阶段。我们在接近中微子退耦区域的球对称壳层内,对中微子量子动力学进行了多角度和多能量的数值模拟。我们依赖来自一维核坍缩超新星模型的输入,该模型质量为 $18.6\\ M_\odot$,并发现在早期反弹后时间($t_{\mathrm{pb}} \lesssim 0.5$~s),电子中微子轻子数角分布中不存在交叉,味转换由慢集体不稳定性触发。角交叉在 $t_{\textrm{pb}} \gtrsim 0.5$~s 时出现,快速味转换导致味均分,使得 $ν_{e}$($\barν_{e}$)和 $ν_{x}$($\barν_{x}$)的能谱分布变得可比拟。值得注意的是,味均分并非快速味转换的普遍结果,而是晚期吸积阶段中不同味中微子具有相对相似性质的结果。通过人为调整碰撞项以在 $t_{\mathrm{pb}} \lesssim 0.05$~s 时引入电子轻子数角交叉,我们观察到未能实现味均分。虽然我们的发现局限于特定超新星模型,且仅考虑了中微子背景对味转换的反馈,但它们表明超新星核心中存在作为反弹后时间函数的丰富唯象学,需进一步探索以评估其对爆炸机制的影响。

英文摘要:

Our understanding of neutrino flavor conversion in the supernova core is still preliminary, despite its likely relevance to the neutrino-driven supernova mechanism. We present multi-angle and multi-energy numerical simulations of neutrino quantum kinetics within a spherically symmetric shell in the proximity of the region of neutrino decoupling. We rely on inputs from a one-dimensional core-collapse supernova model with a mass of $18.6\ M_\odot$ and find that, at early post-bounce times ($t_{\mathrm pb} \lesssim 0.5$~s), no crossing is present in the angular distribution of the electron neutrino lepton number and flavor conversion is triggered by slow collective instabilities. Angular crossings appear for $t_{\textrm{pb}} \gtrsim 0.5$~s and fast flavor conversion leads to flavor equipartition, with the spectral energy distribution of $ν_{e}$ ($\barν_{e}$) and $ν_{x}$ ($\barν_{x}$) becoming comparable. Notably, flavor equipartition is not a generic outcome of fast flavor conversion, rather it is a consequence of the relatively similar properties of neutrinos of different flavors characterizing the late accretion phase. Artificially tweaking the collision term to introduce an electron lepton number angular crossing for $t_{\mathrm{pb}} \lesssim 0.05$~s, we observe that flavor equipartition is not achieved. While our findings are restricted to a specific supernova model, and they only take into account the feedback of the neutrino background on the flavor conversion, they suggest a rich phenomenology in the supernova core as a function of the post-bounce time which needs to be further explored to assess its impact on the explosion mechanism.

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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