Open Questions in Cosmic-Ray Research at Ultrahigh Energies
Résumé
We review open questions and prospects for progress in ultrahigh-energy cosmicray (UHECR) research, based on a series of discussions that took place during the “The High-Energy Universe: Gamma-Ray, Neutrino, and Cosmic-ray Astronomy” MIAPP workshop in 2018.Specifically, we overview open questions on the origin of the bulk of UHECRs, the UHECR mass composition, the origin of the end of the cosmic-ray spectrum, the transition from Galactic to extragalactic cosmic-rays, the effect of magnetic fields on thetrajectories of UHECRs, anisotropy expectations for specific astrophysical scenarios, hadronicinteractions, and prospects for discovering neutral particles as well as new physics at ultrahighenergies. We also briefly overview upcoming and proposed UHECR experiments and discusstheir projected science reach.
Mots clés
Ultrahigh energy cosmic rays
ultrahigh energy neutrinos
extrensive-air-shower detectors
Intergalactic magnetic field
Mass composition of cosmic rays
hadronic interactions at ultrahigh energies
ultrahigh-energy-cosmic-ray anisotropy
cosmic radiation: UHE
cosmic radiation: spectrum
magnetic field: effect
neutral particle
neutrino
mass spectrum
new physics
anisotropy
trajectory
gamma ray
galaxy