Axion and dark photon limits from Crab Nebula high energy gamma-rays. (arXiv:2002.01796v4 [astro-ph.HE] UPDATED)
<a href="http://arxiv.org/find/astro-ph/1/au:+Bi_X/0/1/0/all/0/1">Xiao-Jun Bi</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Gao_Y/0/1/0/all/0/1">Yu Gao</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Guo_J/0/1/0/all/0/1">Junguang Guo</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Houston_N/0/1/0/all/0/1">Nick Houston</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Li_T/0/1/0/all/0/1">Tianjun Li</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Xu_F/0/1/0/all/0/1">Fangzhou Xu</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_X/0/1/0/all/0/1">Xin Zhang</a>

The observation of cosmic sub-PeV gamma-rays from the Crab Nebula opens up
the possibility of testing cosmic ray photon transparency at the multi-hundred
TeV scale. Assuming no deviation from a source gamma-ray emission due to
accelerated electron inverse-Compton scattering, higher event energies can
extend constraints on the effects of new physics; We consider oscillation
between gamma-rays and axions/dark photons, plus attenuation effects from
gamma-ray absorption in the case of dark photon dark matter. Combining the
recent AS$gamma$ and HAWC sub-PeV data with earlier MAGIC and HEGRA data,
axion-like particles are most constrained in the $10^{-7}-10^{-6}$ eV mass
range, where the coupling $g_{agamma}$ is constrained to be below ${1.8}times
10^{-10}$ GeV$^{-1}$. In comparison, gamma ray flux attenuation due to
oscillation with a dark photon leads to a very weak constraint on the mixing
parameter; $epsilonlesssim$ 0.2 for dark photon mass between $10^{-7}$ and
$10^{-6}$ eV. Direct scattering from dark photon dark matter limits
$epsilonlesssim$ 0.01 for masses between $6$ and $400$ eV.

The observation of cosmic sub-PeV gamma-rays from the Crab Nebula opens up
the possibility of testing cosmic ray photon transparency at the multi-hundred
TeV scale. Assuming no deviation from a source gamma-ray emission due to
accelerated electron inverse-Compton scattering, higher event energies can
extend constraints on the effects of new physics; We consider oscillation
between gamma-rays and axions/dark photons, plus attenuation effects from
gamma-ray absorption in the case of dark photon dark matter. Combining the
recent AS$gamma$ and HAWC sub-PeV data with earlier MAGIC and HEGRA data,
axion-like particles are most constrained in the $10^{-7}-10^{-6}$ eV mass
range, where the coupling $g_{agamma}$ is constrained to be below ${1.8}times
10^{-10}$ GeV$^{-1}$. In comparison, gamma ray flux attenuation due to
oscillation with a dark photon leads to a very weak constraint on the mixing
parameter; $epsilonlesssim$ 0.2 for dark photon mass between $10^{-7}$ and
$10^{-6}$ eV. Direct scattering from dark photon dark matter limits
$epsilonlesssim$ 0.01 for masses between $6$ and $400$ eV.

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