LHC creates matter from light

Scientists on an experiment at the Large Hadron Collider see massive W particles emerging from collisions with electromagnetic fields. How can this happen? The Large Hadron Collider plays with Albert Einstein's famous equation, E = mc², to transform matter into energy and then back into different forms of matter. But on rare occasions, it can skip the first step and collide pure energy--in the form of electromagnetic waves. Last year, the ATLAS experiment at the LHC observed two photons, partic...