Testing effects of Lorentz invariance violation in the propagation of astroparticles with the Pierre Auger Observatory

THE PIERRE AUGER COLLABORATION.; S. J. SCIUTTO

JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS

IOP PUBLISHING LTD

Lugar: Londres; Año: 2022 vol. 1

1475-7516

Lorentz invariance violation (LIV) is often described by dispersion relations of theform E2i = m2i+ p2i+ i,nE2+n with delta different based on particle type i, with energy E,momentum p and rest mass m. Kinematics and energy thresholds of interactions are modifiedonce the LIV terms become comparable to the squared masses of the particles involved. Thus,the strongest constraints on the LIV coefficients i,n tend to come from the highest energies.At sufficiently high energies, photons produced by cosmic ray interactions as they propagatethrough the Universe could be subluminal and unattenuated over cosmological distances.Cosmic ray interactions can also be modified and lead to detectable fingerprints in the energyspectrum and mass composition observed on Earth. The data collected at the Pierre AugerObservatory are therefore possibly sensitive to both the electromagnetic and hadronic sectorsof LIV. In this article, we explore these two sectors by comparing the energy spectrum andthe composition of cosmic rays and the upper limits on the photon flux from the Pierre AugerObservatory with simulations including LIV. Constraints on LIV parameters depend stronglyon the mass composition of cosmic rays at the highest energies. For the electromagnetic sector,while no constraints can be obtained in the absence of protons beyond 1019 eV, we obtain,0 > −10−21, ,1 > −10−40 eV−1 and ,2 > −10−58 eV−2 in the case of a subdominantproton component up to 1020 eV. For the hadronic sector, we study the best description ofthe data as a function of LIV coefficients and we derive constraints in the hadronic sectorsuch as had,0 < 10−19, had,1 < 10−38 eV−1 and had,2 < 10−57 eV−2 at 5 CL.