Resonant Neutrino Flavor Conversion in Post Merger Accretion Disk
Neutrino oscillation is a phenomena that has provided a window into physics beyond the Standard Model (SM). It has given empirical evidence that the neutrino has mass that is not generated in the conventional manner of the SM and that efforts need to be made to fundamentally understand its behaviour. Neutrinos have a great role in astrophysics where much of their behaviour and impact has been studied in supernova. Less understood is their role in environments such as the accretion disk formed from a black hole - neutron star merger. This work goes on to analyze resonant neutrino oscillations through the electron background of the accretion disk. The matter basis that defines neutrino evolution in an electron background is derived where exact values are given for the limiting behaviour of the energy eigenvalues. It is shown that the adiabatic condition for varying interaction evolution is satisfied for neutrino propagation in the accretion disk. The H-resonant regions in the accretion disk provide areas for flavor conversion. Dominant neutrino energy resonant oscillation occurs in the outer regions of the disk. Resonant oscillation in the accretion disk alters the neutrino flux. Electron neutrino flux may be decreased in resonant regions for normal ordering mass hierarchy while electron anti neutrino flux may be lowered for inverted ordering.