arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2104.05729astro-ph.HEhep-ph
收藏

用Boltzmann中微子输运标定的零阶和一阶矩构造核塌缩超新星中中微子的角分布

Constructing angular distributions of neutrinos in core collapse supernova from zero-th and first moments calibrated by full Boltzmann neutrino transport

Hiroki Nagakura, Lucas Johns

摘要:

由于两矩中微子输运方法大大减轻了多维中微子辐射流体动力学模拟的计算负担,因此被广泛应用于核心坍缩超新星(CCSN)理论模型的建立。然而,这种近似是有代价的;中微子角分布的详细结构被牺牲了,这是这种方法的主要缺点。本文发展了一种由零阶和一阶角矩构造中微子角分布的新方法。在我们的方法中,角分布是用中微子角的两个二次函数分段表示的。通过与具有完整Boltzmann中微子输运的球对称CCSN模型中的中微子数据的比较,我们确定了拟合函数中的最佳参数。我们证明了我们的方法的能力,通过使用我们最近的二维CCSN模型。我们发现,角分布的基本特征可以很好地重建,而入射中微子的角分布往往有很大的误差,增加通量因子($κ$)。这个问题源于入射中微子对$κ$的不敏感性,这是矩方法的固有局限性。基于演示的结果,我们评估的可靠性ELN交叉搜索与两个时刻中微子输运。这一分析是对我们另一篇文章的补充,该文章用几个时刻仔细研究了交叉搜索的局限性。我们发现入射中微子角分布的系统误差会导致对$κ\gtrsim 0.5$交叉的误判。这使人怀疑ELN交叉搜索的结果,基于两个时刻的方法在以前的一些研究。

英文摘要:

Two-moment neutrino transport methods have been widely used for developing theoretical models of core-collapse supernova (CCSN), since they substantially reduce the computational burden inherent in the multi-dimensional neutrino-radiation hydrodynamical simulations. The approximation, however, comes at a price; the detailed structure of angular distribution of neutrinos is sacrificed, that is the main drawback of this approach. In this paper, we develop a novel method by which to construct angular distributions of neutrinos from the zero-th and first angular moments. In our method, the angular distribution is expressed with two quadratic functions of the neutrino angle in a piecewise fashion. We determine the best parameters in the fitting function by comparing to the neutrino data in a spherically symmetric CCSN model with full Boltzmann neutrino transport. We demonstrate the capability of our method by using our recent 2D CCSN model. We find that the essential features of the angular distributions can be well reconstructed, whereas the angular distributions of incoming neutrinos tend to have large errors that increase with flux factor ($κ$). This issue originates from the insensitiveness of incoming neutrinos to $κ$, that is an intrinsic limitation in moment methods. Based on the results of the demonstration, we assess the reliability of ELN-crossing searches with two-moment neutrino transport. This analysis is complementary to our another paper that scrutinizes the limitation of crossing searches with a few moments. We find that the systematic errors of angular distributions for incoming neutrinos lead to misjudgements of the crossing at $κ\gtrsim 0.5$. This casts doubt on the results of ELN-crossing searches based on two-moment methods in some previous studies.

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。

↑