Nuclear energy release question

[DaveSmith]

A proton and neutron "at rest" may stick to each other forming a deuterium and releasing some 2.2 MeV energy but what if they are streamed to each other at 2 GeV? what will be the output of energy? Do we get more kinetic energy in the form of photons?

 

[Norman]

EDIT: Forgot to address a main point: conservation of energy.

Remember that energy is always conserved. So the 2 GeV of kinetic energy plus the rest mass of the proton and neutron, must also be somewhere in the final state after the reaction.

At 2 GeV kinetic energy, the fusion cross section for pn is likely to be infinitesimal. I don't know off hand its exact value.

You are way above the pion production threshold of 290 MeV and above even the rho-meson threshold at that point. Also you are above the Delta(1232) energy, so particle production via resonance is likely.

So you would much more likely see the extra energy go into the production of secondary particles (mainly pions) in an inelastic scattering event.