In the binary-driven hypernova model of long gamma-ray bursts, a carbon–oxygen star explodes as a supernova in the presence of a neutron star binary companion in close orbit. Hypercritical (i.e., highly super-Eddington) accretion of the ejecta matter onto the neutron star sets in, making it reach the critical mass with consequent formation of a Kerr black hole. We have recently shown that, during the accretion process onto the neutron star, fast neutrino flavor oscillations occur. Numerical simulations of the above system show that a part of the ejecta stays bound to the newborn Kerr black hole, leading to a new process of hypercritical accretion. We address herein, also for this phase of the binary-driven hypernova, the occurrence of neutrino flavor oscillations given the extreme conditions of high density (up to ${10}^{12}$ g cm${}^{-3}$) and temperatures (up to tens of MeV) inside this disk. We estimate the behavior of the electronic and non-electronic neutrino content within the two-flavor formalism (${\nu }_e{\nu }_x$) under the action of neutrino collective effects by neutrino self-interactions. We find that in the case of inverted mass hierarchy, neutrino oscillations inside the disk have frequencies between ∼$({10}^5$–${10}^9)$ s${}^{-1}$, leading the disk to achieve flavor equipartition. This implies that the energy deposition rate by neutrino annihilation ($\nu +\overline{\nu }\to e^{-}+e^{+}$) in the vicinity of the Kerr black hole is smaller than previous estimates in the literature not accounting for flavor oscillations inside the disk. The exact value of the reduction factor depends on the ${\nu }_e$ and ${\nu }_x$ optical depths but it can be as high as ∼5. The results of this work are a first step toward the analysis of neutrino oscillations in a novel astrophysical context, and as such, deserve further attention.

中文翻译：

---

旋转黑洞周围中微子占主导地位的吸积中的中微子振荡。

在长伽马射线暴的双星驱动的超新星模型中，当中子星双星伴星在近轨道上存在时，碳-氧星爆炸成超新星。喷射物质在中子星上的超临界（即高度超爱丁顿）积聚开始，使其达到临界质量，从而形成Kerr黑洞。我们最近发现，在中子星上的吸积过程中，会发生快速的中微子风味振荡。上述系统的数值模拟表明，喷射器的一部分与新生的Kerr黑洞保持结合，从而导致了超临界吸积的新过程。对于二元驱动的超新星的这一阶段，我们在这里也要解决的是，在高密度（达到${10}^{12}$ 克厘米${}^{-3}$）和此磁盘内的温度（最高为几十MeV）。我们估计两种风味形式主义中电子和非电子中微子含量的行为（${\nu }_{Ë}{\nu }_X$）在中微子的集体作用下，通过中微子的自我相互作用。我们发现，在质量倒排的情况下，圆盘内部的中微子振荡的频率在〜之间。$（{10}^5$–${10}^9）$ s${}^{-\mathrm{1个}}$，导致磁盘达到风味均分。这意味着中微子an灭的能量沉积速率（$\nu +\overline{\nu }\to {Ë}^{-}+{Ë}^{+}$）在Kerr黑洞附近小于文献中的先前估计值，未考虑盘内部的风味振荡。折减系数的确切值取决于${\nu }_{Ë}$ 和 ${\nu }_X$光学深度，但可以高达〜5。这项工作的结果是在新颖的天体物理学背景下分析中微子振荡的第一步，因此，值得进一步关注。