Speaker
Description
Axion-like particles (ALPs), predicted in extensions of the Standard Model, arise as candidates for cold dark matter. Their coupling to photons in external magnetic fields leads to photon–ALP oscillations, which can affect the propagation of very-high energy gamma rays over astrophysical distances. Such effects may manifest as energy dependent distortions and small-scale irregularities in the Spectral Energy Distribution (SED).
In this work, we use reported fluxes by LHAASO and employ an irregularity estimator, $I^{2}$, to characterize local deviations in the very-high-energy gamma-ray spectrum of the Crab Nebula. Different SEDs were simulated from fluctuations in the reported flux and an $I^2$ distribution was estimated assuming no ALP effects. Subsequently ALP-Photon Mixing was incorporated, allowing the generation of $I^2$ distributions for various values of ALP mass $(m_a)$ and coupling $(g_{a\gamma})$. Based on a statistical comparison of the distributions, an exclusion region was derived in the ALP parameter space in the range of $m_a$ from $10^{-8}$ eV to $10^{-6}$ eV and $g_{a \gamma}$ from $10^{-11}$GeV $^{-1}$ to $10^{-10}$ GeV $^{-1}$.
This work was supported by UNAM-PAPIIT IG100726 and SECIHTI LNC-2023-117.