Propagation of Neutrinos through Magnetized Gamma-Ray Burst Fireball

TL;DR

This paper calculates neutrino propagation and oscillation probabilities in magnetized gamma-ray burst fireballs, considering magnetic effects, and explores their implications for neutrino flavor conversion in such extreme environments.

Contribution

It provides a detailed calculation of neutrino effective potentials in magnetized plasma and analyzes neutrino oscillations within gamma-ray burst fireballs, including resonance conditions and probabilities.

Findings

Neutrino oscillation probabilities depend on fireball parameters and magnetic field presence.

Electron neutrinos are less likely to oscillate into other flavors in the fireball.

Muon and tau neutrinos oscillate with equal probability, influenced by energy and environment.

Abstract

The neutrino self-energy is calculated in a weakly magnetized plasma consists of electrons, protons, neutrons and their anti-particles and using this we have calculated the neutrino effective potential up to order $M^{-4}_W$. In the absence of magnetic field it reduces to the known result. We have also calculated explicitly the effective potentials for different backgrounds which may be helpful in different environments. By considering the mixing of three active neutrinos in the medium with the magnetic field we have derived the survival and conversion probabilities of neutrinos from one flavor to another and also the resonance condition is derived. As an application of the above, we considered the dense and relativistic plasma of the Gamma-Ray Bursts fireball through which neutrinos of 5-30 MeV can propagate and depending on the fireball parameters they may oscillate resonantly or non-resonantly from one flavor to another. These MeV neutrinos are produced due to stellar collapse or merger events which trigger the Gamma-Ray Burst. The fireball itself also produces MeV neutrinos due to electron positron annihilation, inverse beta decay and nucleonic bremsstrahlung. Using the three neutrino mixing and considering the best fit values of the neutrino parameters, we found that electron neutrinos are hard to oscillate to another flavors. On the other hand, the muon neutrinos and the tau neutrinos oscillate with equal probability to one another, which depends on the neutrino energy, temperature and size of the fireball. Comparison of oscillation probabilities with and without magnetic field shows that, they depend on the neutrino energy and also on the size of the fireball. By using the resonance condition, we have also estimated the resonance length of the propagating neutrinos as well as the baryon content of the fireball.