Neutron star merger remnants are unique sites for exploring neutrino flavor conversion in dense media. Because of the natural excess of ν̅_e over ν_e , the neutrino-neutrino potential can cancel the matter potential, giving rise to matter-neutrino resonant flavor conversion. Under the assumption of two (anti)neutrino flavors and spatial homogeneity, we solve the neutrino quantum kinetic equations to investigate the occurrence of the matter-neutrino resonance within a multi-angle framework. We find that isotropy is broken spontaneously, regardless of the mass ordering. Relying on a hydrodynamical simulation of a binary neutron star merger remnant with a black hole of 3 M _⊙ and an accretion torus of 0.3 M _⊙, we find that complete flavor conversion caused by the matter-neutrino resonance is unlikely, although the matter and neutrino potentials cancel at various locations above the disk. Importantly, the matter-neutrino resonant flavor conversion crucially depends on the shape of the neutrino angular distributions. Our findings suggest that an accurate modeling of the neutrino angular distributions is necessary to understand flavor conversion physics in merger remnants, its implications on the disk physics and synthesis of the elements heavier than iron.

中文翻译：

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中子星并合遗迹中多角度物质-中微子共振引起的对称性破缺

中子星合并遗迹是探索致密介质中中微子味道转换的独特场所。由于自然过剩ν̅e_​ 超过ν_​ ，中微子-中微子势能抵消物质势，引起物质-中微子共振味转换。在两种（反）中微子味道和空间均匀性的假设下，我们求解中微子量子动力学方程，以研究多角度框架内物质-中微子共振的发生。我们发现，无论质量顺序如何，各向同性都会自发破坏。依赖于具有黑洞 3 的双中子星合并残骸的流体动力学模拟中号 _⊙吸积环为 0.3中号 _⊙，我们发现，尽管物质和中微子势在圆盘上方的不同位置抵消，但由物质-中微子共振引起的完全味道转换是不可能的。重要的是，物质-中微子共振味道转换很大程度上取决于中微子角分布的形状。我们的研究结果表明，对中微子角分布进行精确建模对于理解合并残余物中的味道转换物理、其对盘物理和比铁重元素的合成的影响是必要的。