Axion and Dark Photon Limits from Crab Nebula High-Energy Gamma Rays

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, 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, axionlike particles are most constrained in the 2 x 10(-7) -6 x 10(-7) eV mass range, where the coupling g(a gamma gamma) is constrained to be below 1.8 x 10(-10) GeV-1. Direct scattering from dark photon dark matter limits kinetic mixing epsilon less than or similar to 1.0(-3) f or masses between 0.01 and 1 eV.