Recently, the anomalous decay rate of quasinormal modes has been studied for some geometries under scalar field perturbations, which occurs when the longest-lived modes are the ones with higher angular number, as well as the existence of a critical scalar field mass, i.e., the value of scalar field mass such that the decay rate does not depend appreciably on the angular number, and beyond which the behavior of the decay rate is inverted. Here, we consider the propagation of fermionic fields in the background of Schwarzschild–de Sitter black holes, and we show that the anomalous decay rate behavior and the fine structure, related to the coupling between the chirality and the mass of the field, can be observed in the fermionic spectrum.

• Received 13 October 2020
• Accepted 9 February 2021

DOI:https://doi.org/10.1103/PhysRevD.103.064006