Neutrino oscillations above black hole accretion disks: Disks with electron-flavor emission

Abstract

Black hole accretion disks can form through the collapse of rotating massive stars. These disks produce large numbers of neutrinos and antineutrinos of electron flavor that can influence energetics and nucleosynthesis. Neutrinos are produced in sufficient numbers that, after they are emitted, they can undergo flavor transformation facilitated by the neutrino self interaction. We show that some of the neutrino flavor transformation phenomenology for accretion disks is similar to that of the supernova case, but also, we find the disk geometry lends itself to different transformation behaviors. These transformations strongly influence the nucleosynthetic outcome of disk winds.

Matter-neutrino resonance transitions above a neutron star merger remnant

“…Therefore, it is likely that this oscillation has an effect on any type of nucleosynthesis that is influenced by the neutrinos, for example, wind nucleosynthesis. As pointed out in Ref [37,38] and confirmed in our calculations, the starting sites of MNR transitions may be close to the emission surface of electron neutrinos and anti-neutrinos. Since the neutrinos can be fully converted during standard MNR, the neutron richness of the outflow can be altered through the weak interactions, which results in fewer seed nuclei and more free neutrons available for capture on the seeds.…”

“…4. Previous works [37][38][39][40][41] have shown that a MNR transition is triggered at roughly the point where the total on diagonal Hamiltonian becomes approximately zero, i.e.…”

“…In merger remnant environments, it has been suggested that neutrinos can undergo not only the same type of flavor transformations as in supernova scenarios, but also a novel type of transition called Matter-Neutrino Resonance (MNR) transitions, first observed in [38]. This phenomenon is distinct from the nutation/bipolar oscillation and typically occurs closer to the neutrino emitting surface.…”

“…Symmetric MNR transitions differ from Standard MNR transitions in that they occur when geometric effects cause the system to pass from a region where antineutrinos dominate the neutrino self interaction potential to a region where neutrinos dominate this potential [37,40]. Both types of transformation may well influence nucleosynthesis [37,38] as MNR transitions typically occur closer to the emitting surface of neutrinos than other large scale oscillation phenomena.…”

Black hole spin influence on accretion disk neutrino detection

“…fluxes, energies, and luminosities, observed at the point of emission will be different from the ones registered by an observer positioned anywhere else. The observed quantities change due to neutrino oscillations [30,31], neutrino interactions, and the gravitational field of the BH. For the latter, the consideration of the 3D geometry of the source is of particular importance, as the relativistic effects (bending of neutrino trajectories and energy shifts) depend on the space-time curvature.…”