Sub-photospheric internal shocks and transverse differences of the bulk Lorentz factor in relativistic fireball models of GRB lead to neutron diffusion relative to protons , resulting in inelastic nuclear collisions .
This results in significant fluxes of \nu _ { \mu } ( \bar { \nu } _ { \mu } ) of \sim 3 GeV and \nu _ { e } ( \bar { \nu } _ { e } ) of \sim 2 GeV , scaling with the flow Lorentz factor \eta < \eta _ { \pi } \sim 400 .
This extends significantly the parameter space for which neutrinos from inelastic collision are expected , which in the absence of the above effects requires values in excess of \eta _ { \pi } .
A model with sideways diffusion of neutrons from a slower wind into a fast jet can lead to production of \nu _ { \mu } ( \bar { \nu } _ { \mu } ) and \nu _ { e } ( \bar { \nu } _ { e } ) in the 2-25 GeV or higher range , depending on the value of \eta .
The emission from either of these mechanisms from GRB at redshifts z \sim 1 may be detectable in suitably densely spaced detectors .