New constraints on Lorentz Invariance violation from Crab Nebula spectrum beyond 100 TeV

Abstract

Recently two collaborations, Tibet and HAWC, presented new measurements of gamma-ray spectrum from Crab Nebula [1],[2] which continues beyond 100 TeV. We use these data to establish two-sided constraints on parameters of Lorentz Invariance violation in quantum electrodynamics. The new constraints are several times stronger than existing in the literature. *

Constraints on Lorentz Invariance Violation from HAWC Observations of Gamma Rays above 100 TeV

“…2 shows previous strong limits on photon decay using VHE photons from HEGRA telescope [12,29], CANGAROO [17], and HESS [15]. We also show limits due to LIV energy-dependent time delay searches with the Fermi-LAT [18], and limits due to photon splitting [19,20]. For a more comprehensive list of these limits and those presented in this work including corresponding values of α n , see the Supplemental Material [51].…”

“…In the photon sector, some effects of LIV are expected to increase with energy and over long distances due to cumulative processes in photon propagation. Therefore, astrophysical searches provide sensitive probes of LIV and its potential signatures, such as energy-dependent time delay, photon splitting, vacuum Cherenkov radiation, photon decay, and many other phenomena [12][13][14][15][16][17][18][19][20].…”

“…Photon decay to light fermions proceeds over short distances (centimeters or less) once above the energy threshold of the process [12][13][14][15][16][17]; which would lead to a hard cutoff at high photon energies in astrophysi-cal spectra [27]. Another process, the photon decay into multiple photons [19,20,28], also predicts a significant reduction of the photon flux at VHEs beyond which no photons should reach the Earth from astrophysical distances.…”

“…Refs. [19,20,28] discuss a different method of setting limits on subluminal LIV with n = 2 using modifications to the Bethe-Heitler interaction of photons in the atmosphere. However, unlike the photon splitting process, this does not result in a sharp effective threshold.…”

Phenomenology of the propagation of astroparticles: Lorentz invariance violation and the origin of ultra-high energy cosmic rays

“…The modification of the dispersion relation due to LIV may lead to several effects which would leave imprints in the data, such as time delay between photons of different energies due to a dependency of the speed of light on energy (100,101), photon decay, which would be forbidden by energy-momentum conservation in Lorentz invariant (LI) scenario (102)(103)(104), emission of vacuum Cherenkov (102), modifications in the development of EAS (105,106) and changes in the kinematics of interactions during astroparticle propagation. (88,(107)(108)(109)(110)(111)(112) Over the last decades, several instruments and datasets have been used to search for signatures of these effects.…”