  We present a model of ultra-high-energy cosmic ray (UHECR) production in the
shock-accelerated fireball of a gamma-ray burst. In addition to the standard
UHECR origin from neutron escape and decay into protons, our model considers
direct proton emission through leakage from the edges of the accelerated
baryon-loaded shells that make up the fireball. Depending on the optical
thickness of the shells to photohadronic interactions, the source falls in one
of three scenarios: the usual, optically thin source dominated by neutron
escape, an optically thick source to neutron escape, or a "direct escape"
scenario, where the main contribution to UHECRs comes from the leaked protons.
The associated neutrino production will be different for each scenario, and we
see that the standard "one neutrino per cosmic ray" assumption is valid only in
the optically thin case, while more than one neutrino per cosmic ray is
expected in the optically thick scenario. In addition, the extra direct escape
component enhances the high-energy part of the UHECR flux, thus improving the
agreement between the predictions and the observed flux.

High Energy Astrophysical Phenomena;High Energy Physics - Phenomenology