Constraints on axionlike particles from a combined analysis of three flaring <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>F</mml:mi><mml:mi>e</mml:mi><mml:mi>r</mml:mi><mml:mi>m</mml:mi><mml:mi>i</mml:mi></mml:math> flat-spectrum radio quasars
James Davies, M. Meyer, Garret Cotter
Abstract
Many theories beyond the Standard Model of particle physics predict the existence of axionlike particles (ALPs) that mix with photons in the presence of a magnetic field. Searching for the effects of ALP-photon mixing in gamma-ray observations of blazars has provided some of the strongest constraints on ALP parameter space so far. Previously, only individual sources have been analyzed. We perform a combined analysis on Fermi Large Area Telescope data of three bright flaring flat-spectrum radio quasars, with the blazar jets themselves as the dominant mixing region. For the first time, we include a full treatment of photon-photon dispersion within the jet and account for the uncertainty in our $B$-field model by leaving the field strength free in the fitting. Overall, we find no evidence for ALPs but are able to exclude the ALP parameters $5\text{ }\text{ }\mathrm{neV}\ensuremath{\lesssim}{m}_{a}\ensuremath{\lesssim}200\text{ }\text{ }\mathrm{neV}$ and ${g}_{a\ensuremath{\gamma}}\ensuremath{\gtrsim}5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}12}\text{ }\text{ }{\mathrm{GeV}}^{\ensuremath{-}1}$ with 95% confidence.