Horace An immediate response is this: if that if two deflated protons can get together in such a way as in the second reaction - then why would they not simply emerge as deuterium most of the time? i.e. a deflated version of P-e-P ?
You tend to subscribe to Ockham more than me, so why not go with the simplest alternative? As a magic number and extremely stable nucleus - Ni --> Zn seems to be so unnecessary. Jones I originally proposed the following reactions as justifying the Rossi results: 58Ni28 + p* --> 59Cu29 * --> 59Ni28 + neutrino 58Ni28 + 2 p* --> 60Zn30 * --> 60Ni28 + 2 neutrinos 60Ni28 + p* --> 61Cu29 * --> 61Ni28 + neutrino 61Ni28 + p* --> 62Cu29 * --> 62Ni28 + neutrino 62Ni28 + p* --> 63Cu29 64Ni28 + p* --> 65Cu29 This has the now obvious problem of producing radioactive 59Ni, via the first reaction. Is there any potential reason only the second reaction should be probable? Yes.

