Are you discounting QM and quantum tunneling?
One could say that the in tunneling - threshold energy is briefly "borrowed" and then a short time later, the "debt" is repaid – before the net gain is obvious. From: David Roberson Could you help me understand how the 5.6 MeV is recovered or released? Is there extra energy released into the copper crystal structure that equals this magnitude? I am having a difficult time trying to get back the 5.6 MeV to make the next proton energetic enough for the next reaction. Forgive me for being ignorant about this mechanism, but it truly is difficult to visualize.
