Fermi acceleration under Lorentz invariance violation

TL;DR

This paper investigates how Lorentz invariance violation (LIV) affects particle acceleration in astrophysical sources via the Fermi mechanism, revealing significant spectral modifications at high energies.

Contribution

It provides the first detailed analysis of how LIV alters the energy spectrum and acceleration times in Fermi acceleration, expanding LIV search strategies.

Findings

LIV causes strong suppression of high-energy particle spectra.

Acceleration times are significantly affected by LIV at energies beyond the LIV threshold.

The study completes the understanding of LIV effects on Fermi acceleration mechanisms.

Abstract

In this paper, the acceleration of particles in astrophysical sources by the Fermi mechanism is revisited under the assumption of Lorentz invariance violation (LIV). We calculate the energy spectrum and the acceleration time of particles leaving the source as a function of the energy beyond which the Lorentz invariance violation becomes relevant. Lorentz invariance violation causes significant changes in the acceleration of particles by the first and second-order Fermi mechanisms. The energy spectrum of particles accelerated by first-order Fermi mechanism under LIV assumption shows a strong suppression for energies above the break. The calculations presented here complete the scenario for LIV searches with astroparticles by showing, for the first time, how the benchmark acceleration mechanisms (Fermi) are modified under LIV assumption.