The Role of Stochastic Acceleration in the Prompt Emission of Gamma-Ray Bursts: Application to Hadronic Injection

TL;DR

This paper investigates how stochastic acceleration of particles in gamma-ray burst jets can produce observed spectral features and additional high-energy components, linking particle physics processes to observed gamma-ray and neutrino signals.

Contribution

It introduces a combined analytical and numerical study of particle re-acceleration in GRBs, demonstrating its ability to reproduce observed spectra and predict high-energy neutrino signals.

Findings

Reproduces Band function spectra with alpha~1 and beta~2-3 in the MeV range.

Predicts an additional hard component from proton-induced cascades.

Discusses implications for high-energy neutrino observations.

Abstract

We study effects of particle re-acceleration (or heating) in the post-shock region via magnetohydrodynamic/plasma turbulence, in the context of a mixed hadronic-leptonic model for the prompt emission of gamma-ray bursts (GRBs), using both analytical and numerical methods. We show that stochastically accelerated (or heated) leptons, which are injected via pp and pg reactions and subsequent pair cascades, are plausibly able to reproduce the Band function spectra with alpha~1 and beta~2-3 in the ~MeV range. An additional hard component coming from the proton-induced cascade emission is simultaneously expected, which is compatible with observed extra power-law spectra far above the MeV range. We also discuss the specific implications of hadronic models for ongoing high-energy neutrino observations.