Gee, physicists don't know everything there is to know about atomic physics... could it be that the 'Standard Model' is missing a few parts!
https://phys.org/news/2018-01-result-scientists.html "What we observed was totally amazing," said Brookhaven physicist Alexander Bazilevsky, a deputy spokesperson for the PHENIX collaboration at RHIC, which is reporting these results in a new paper just published in Physical Review Letters. "Our findings may mean that the mechanisms producing particles along the direction in which the spinning proton is traveling may be very different in <https://phys.org/tags/proton-proton+collisions/> proton-proton collisions compared with proton-nucleus collisions." Understanding different particle production mechanisms could have big implications for interpreting other high-energy particle collisions, including the interactions of ultra-high-energy cosmic rays with particles in the Earth's atmosphere, Bazilevsky said. -Mark Iverson