Collisional flavor instability in dense neutrino gases

Zewei Xiong; Lucas Johns; Meng-Ru Wu; Huaiyu Duan

doi:10.1103/PhysRevD.108.083002

paper

Collisional flavor instability in dense neutrino gases

arXiv:2212.03750 · doi:10.1103/PhysRevD.108.083002

Abstract

Charged-current neutrino processes such as $ν_{e} + n ⇌ p + e^{-}$ and $ν ˉ_{e} + p ⇌ n + e^{+}$ destroy the flavor coherence among the weak-interaction states of a single neutrino and thus damp its flavor oscillation. In a dense neutrino gas such as that inside a core-collapse supernova or the black hole accretion disk formed in a compact binary merger, however, these "collision" processes can trigger large flavor conversion in cooperation with the strong neutrino-neutrino refraction. We show that there exist two types of collisional flavor instability in a homogeneous and isotropic neutrino gas which are identified by the dependence of their real frequencies on the neutrino density $n_{ν}$ . The instability transitions from one type to the other and exhibits a resonance-like behavior in the region where the net electron lepton number of the neutrino gas is negligible. In the transition region, the flavor instability grows exponentially at a rate $\propto n_{ν}^{1/2}$ . We find that the neutrino gas in the black hole accretion disk is susceptible to the collision-induced flavor conversion where the neutrino densities are the highest. As a result, large amounts of heavy-lepton flavor neutrinos may be produced through flavor conversion, which can potentially have important ramifications in the subsequent evolution of the remnant.

6 pages, 3 figures. Minor changes to match the published version

Collisional flavor instability in dense neutrino gases

Abstract

References in corpus (13)

Cited by in corpus (30)