This unified <e1>theory</e1> was governed by the <e2>exchange</e2> of four particles: the photon for electromagnetic interactions, a neutral Z particle and two charged W particles for weak interaction.
This unified theory was
This unified theory was governed by the exchange of four particles: the photon for electromagnetic interactions, a neutral Z particle and two charged W particles for weak interaction.
<triplet> theory <subject> exchange <object> Other