Speaker
Description
We fit the recent UHECR spectrum measurements from the Telescope Array
experiment under the assumption of pure proton composition, as assumed by the proton dip model.
We present a a full scan of the three main physical model parameters of
UHECR-injection: source redshift evolution, injected maximal proton energy
and spectral power-law index. We discuss how the result qualitatively
changes compared to earlier two-parameter fits in the literature: : a
mild preference
for a maximal energy cutoff at the sources instead of the
Greisen–Zatsepin–Kuzmin (GZK) cutoff, hard injection spectra, and strong
source evolution.
We show that the predicted neutrino flux exceeds the IceCube
limit for any parameter combination. As a result, the proton dip model
is challenged at more than 95% C.L.
This is strong evidence against the dip-model independent of mass
composition measurements.
