Data reveal a surprising preference in particle spin alignment

Given the choice of three different ‘spin’ orientations, certain particles emerging from collisions at the Relativistic Heavy Ion Collider (RHIC), an atom smasher, appear to have a preference. Recent results reveal a preference in global spin alignment of particles called phi mesons. Conventional mechanisms — such as the magnetic field strength or the swirliness of the matter generated in the particle collisions — cannot explain the data. But a new model that includes local fluctuations in the nuclear strong force can.