Speaker
Description
The origin and composition of ultra-high energy cosmic rays (UHECRs) remain unresolved, particularly for events exceeding the Greisen–Zatsepin–Kuzmin cutoff and and whose apparent arrival directions do not point to plausible sources.
This work investigates the hypothesis that a fraction of such events could be associated with low-mass magnetic monopoles (MMs) predicted in several theoretical frameworks. Using a custom extension of the CRPropa framework, a state-of-the-art tool for simulating charged particle propagation in astrophysical environments, MMs trajectories are modeled within realistic Galactic magnetic field configurations, exploring a range of assumptions on mass, magnetic charge, and initial phase-space distributions. Two representative production scenarios are considered: relic MMs originating from primordial cosmological phase transitions, and MMs produced via the Schwinger effect by astrophysical point sources, such as magnetars. Simulations predict that the distribution of arrival directions at Earth of light MMs is markedly anistropic for most scenarios, with the details depending on the production history and particle rigidity. The simulated arrival distributions are compared with the existing UHECRs data. Implication of the results for the existing and future MM searches will also be discussed.
