Constraints on Axion-like Particles from Observations of Mrk 421 using the $\mathrm{C}{\mathrm{L}}_{\mathrm{s}}$ Method

Lin-Qing Gao, Xiao-Jun Bi, Jun-Guang Guo +2

Axion-like particles (ALPs) may undergo mixing with photons in the presence of astrophysical magnetic fields, leading to alterations in the observed high energy $\gamma$-ray spectra. In…