# Neutrino oscillations and decoherence in short-GRB progenitors

## TL;DR

This paper investigates how neutrino flavor oscillations and decoherence affect the neutrino signals from short gamma-ray burst progenitors, using the Fireshell Model and considering interactions near black holes.

## Contribution

It introduces a detailed analysis of neutrino decoherence effects in short GRBs, highlighting their impact on the flavor composition of neutrinos detected on Earth.

## Key findings

- Decoherence significantly alters neutrino flavor states during propagation.
- Approximately 67.8% of electron-neutrinos remain as electron-neutrinos after decoherence.
- Decoherence influences the observable neutrino flux, affecting source reconstruction.

## Abstract

Neutrinos are produced in cosmic accelerators, like active galactic nuclei (AGNs), blazars, supernova (SN) remnants and gamma-ray bursts (GRBs). On their way to the Earth they experience flavor-oscillations. The interactions of the neutrinos coming from the source with other particles, e.g. intergalactic primordial neutrinos or heavy-mass right-handed neutrinos, in their way to the detector may transform the original wave packet in pointer states. This phenomenon, known as decoherence, becomes important in the reconstruction of processes at the source. In this work we study neutrino emission in short GRBs by adopting the Fireshell Model. We consider $e^{-}e^{+}$-pair annihilation as the main channel for neutrino production. We compare the properties of the neutrino-flux with the characteristic photon-signal produced once the transparency condition is reached. We study the effects of flavor-oscillations and decoherence as neutrinos travel from the region near the black-hole (BH) event-horizon outwards. We consider the source to be in thermal equilibrium, and calculate energy distribution functions for electrons and neutrinos. To compute the effects of decoherence we use a Gaussian model. In this scenario the emitted electron-neutrinos transform into pointer states consisting of $67.8\%$ electron-neutrinos and $32.2\%$ as a combination of mu and tau neutrinos. We found that decoherence plays an important role in the evolution of the neutrino wave packet, leading to the detected pointer states on Earth.