I’m jumping into this thread a bit late but the concept of a “mystery” radiation or particle is intriguing, especially in the context of Holmlid’s muons. (which as Bob Higgins sez are unlikely to be muons).
Could Holmlid be seeing something else instead of muons (mesons, pions, kaons, etc) ? My answer is: yes, almost certainly. Holmlid faces an insurmountable physics problem by almost ignoring the charge of muons. He is, in effect, inventing a new particle – a chargeless muon. That is NEVER going to fly. Instead it would make far more sense to characterize the mystery particle in ways that mesh with standard physics. Start by giving it a new name. However, the name meshugganon is a bit crazy <G> even to one who loves Yiddish. What about Ferron ? The best candidate particle missing from the discussion even though it has been published to a limited audience is the work of John P Wallace, who is perhaps the leading expert in the USA on the subject of iron. He is almost obsessive, it would seem – which is a good thing for science. Here is one reference to this particle which is basically a carrier of spin. Nothing makes more sense in terms of applicability to Holmlid’s mystery than a particle which is unique to iron and represents quanta of spin energy. https://arxiv.org/abs/0901.1631 ➢ AA: Muons will get through all of that light material with no problem. But muons will be captured by the iron body of a pancake detector. The muon can then canalize fission reactions in the iron and the gas in the pancake detector will register radiation generated by the fission reaction…. If you place some more iron or lead between the experiment and the detector head, and the counts go up.. then you are seeing muons. If Wallace is correct – iron will give a stronger response than any other metal to a flux of the mystery particle – including nickel or lead. Jones