One of these particles produces an electron and a 
One of these particles produces an electron and a positron in pair production. One of them is spontaneously emitted when a nucleus in an excited state transitions to a ground state. These particles were emitted in Thomas Young's double-slit experiment, which demonstrated wave-particle duality. They mediate the electromagnetic interaction. For 10 points, name these particles which make up light.
One of these particles produces an electron and a positron in pair production.
{photons}