Charged black holes in Kalb-Ramond gravity: Weak Deflection Angle, Shadow cast, Quasinormal Modes and Neutrino annihilation

TL;DR

This paper explores charged black holes within a Lorentz-violating Kalb-Ramond gravity framework, analyzing light deflection, shadows, quasinormal modes, and neutrino annihilation, and compares predictions with observational data to test the model.

Contribution

It provides analytic expressions for light deflection and shadow deformation in Kalb-Ramond gravity, incorporating Lorentz-violating effects and validating the model with observational constraints.

Findings

Persistent Lorentz-violating corrections to deflection angles

Deformation of photon sphere and impact parameters due to KR effects

Constraints on Lorentz-violating parameter from EHT data

Abstract

In this paper, we investigate the phenomenology of electrically charged black holes in a Lorentz-violating gravitational framework mediated by a background Kalb-Ramond (KR) antisymmetric tensor field. Employing the Gauss-Bonnet theorem in a non-asymptotically flat geometry, we derive analytic expressions for the weak deflection angle of light and massive particles, revealing persistent corrections due to the Lorentz-violating parameter $ \ell $. Scalar and Dirac perturbations are also studied using both the WKB approximation and the Poschl-Teller approximation approach to verify the stability of the solution against these types of perturbations. Shadow analysis further uncovers a nontrivial deformation of the photon sphere and critical impact parameter, with KR-induced effects modifying the charge contribution in a manner incompatible with standard Einstein-Maxwell theory. Constraints derived from Event Horizon Telescope data for Sgr A* and M87* validate the model and provide stringent bounds on $ \ell $, establishing the KR framework as an observationally testable extension of General Relativity.