High energy physics experiments have shown a clear difference in how the proton's three building blocks, quarks, are distributed in heavy nuclei versus light nuclei or hydrogen. This difference is called the EMC Effect. This might have relevance to the Rossi experiment, or not.
http://arxiv.org/PS_cache/arxiv/pdf/0706/0706.2937v2.pdf "On the dependence of the wave function of a bound nucleon on its momentum and the EMC effect" Background: The European Muon Collaboration (EMC) conducted high energy particle physics experiments at CERN. In 1983, it discovered that nucleons inside a nucleus have a different distribution of momentum among their component quarks based on mass. This is the original so-called "EMC Effect". In 1987, the group discovered that only a small part of the proton spin is carried by quarks, and that the "strange quark sea" is probably polarized. The former is sometimes referred to as the "proton spin crisis". This may have relevance as well. The probability of finding two nucleons close together in the nucleus is called a short-range correlation; the probability that the two nucleons are in a short-range correlation increases as the nucleus gets heavier." Protons don't act as if they are individual particles when in a heavy nucleus; their "point like correlation (PLC)" is increasingly depressed as the number of nucleons Z increases. The provocative conjecture of a poster known as "Axil" is that the EMC effect causes the hydrogen nucleus of a hydride to merge with heavy nucleus of the nickel atom when the momentum of the nickel atom is increased by the motion of vibration of the metal lattice to a certain level - which seems to be a threshold temperature in a narrow range. The radius of the metal atom increasingly grows with increasing vibrational momentum until the combined wave form of all the constituent nucleons in the nucleus of the metal overlaps, encompasses and combines with the wave form of the hydrided proton. This conjecture has a lot of appeal for reasons which are not easy to articulate. Jones
