2021/08/12 by Marco Stein Muzio, Muzio, Marco Stein, Glennys R. Farrar +3 · 2 citations
Physics and Astronomy · Engineering · #Astrophysics and Cosmic Phenomena #Neutrino Physics Research #Particle Accelerators and Free-Electron Lasers
paper · pdf · doi:10.48550/arxiv.2108.05512
We explore inferences on ultrahigh energy cosmic ray (UHECR) source environments -- constrained by the spectrum and composition of UHECRs and non-observation of extremely high energy neutrinos -- and their implications for the observed high energy astrophysical neutrino spectrum. We find acceleration mechanisms producing power-law CR spectra~∝ E-2 are compatible with UHECR data, if CRs at high rigidities are in the quasi-ballistic diffusion regime as they escape their source environment. Both gas-dominated and photon-dominated source environments are able to account for UHECR observations, however photon-dominated sources give a better fit. Additionally, gas-dominated sources are in tension with current neutrino constraints. Accurate measurement of the neutrino flux at ∼ 10 PeV will provide crucial information on the viability of gas-dominated sources, as well as whether diffusive shock acceleration is consistent with UHECR observations. We also show that UHECR sources are able to give a good fit to the high energy portion of the astrophysical neutrino spectrum, above ∼ PeV. This common origin of UHECRs and high energy astrophysical neutrinos is natural if air shower data is interpreted with the Sibyll2.3c hadronic interaction model, which gives the best-fit to UHECRs and astrophysical neutrinos in the same part of parameter space, but not for EPOS-LHC.