Geneva, 11 February 2015. In a paper published yesterday in the journal Physical Review Letters, the COMPASS experiment at CERN1 reports a key measurement on the strong interaction. The strong interaction binds quarks into protons and neutrons, and protons and neutrons into the nuclei of all the elements from which matter is built. Inside those nuclei, particles called pions made up of a quark and an antiquark mediate the interaction.
11 Feb 2015