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تسجيل مستخدم جديدLimits on axion-like particles from Mrk 421 with 4.5-years period observations by ARGO-YBJ and Fermi-LAT
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In this work, we investigate the axion-like particle (ALP)-photon oscillation effect in the spectra of the blazar Markarian 421 (Mrk 421) using 4.5 years of the ARGO-YBJ and Fermi-LAT data. These data are collected during the common operation time, which cover ten activity phases of Mrk 421. No significant ALP-photon oscillation effect is confirmed. Only the observations of three phases can be individually used to set the $95%$ $rm C.L.$ constraint on the ALP parameter space. However, the constraint can be significantly improved if the analyses for the observations of ten phases are combined. We find that the Mrk 421 observations of ARGO-YBJ and Fermi-LAT have excluded the ALP parameter region with the ALP-photon coupling of $g_{agamma} gtrsim 3 times 10^{-11}$ $rm GeV^{-1}$ for the ALP mass of $sim 3times 10^{-10}$ eV $lesssim m_a lesssim 2times 10^{-8}$ eV.
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