Analytic stochastic propagation of UHECRs
by
seminar room 3
bldg. 1b
Photonuclear interactions between ultra-high-energy cosmic ray (UHECR) nuclei and background photons are key to understanding the connection between the compositions observed at Earth and those emitted from the sources. The stochastic nature of these interactions means that it is not possible to describe them deterministically for a single cosmic ray, and an exact formulation of the probability distributions has not been derived. Currently these interactions are described via Monte Carlo simulations or solving ordinary differential equations that neglect stochasticity. I present an analytic probabilistic description of UHECR interactions and the resulting nuclear cascades applying the theory of Markov jump processes. The fundamental properties of these cascades will be discussed, and related to quantities of interest such as the horizon, spectrum, and composition evolution. Finally, I examine the possibility of using this framework for back propagation of observed cosmic rays.