Feynman used Ernst Stueckelberg's interpretation of the positron as if it were an electron moving backward in time. Thus, antiparticles are represented as moving backward along the time axis in Feynman diagrams.
Feynman used Ernst Stueckelberg's interpretation of the positron as if it were an electron moving backward in time. Thus antiparticles are represented as moving backward along the time axis in Feynman diagrams