text: W ' and Z ' bosons refer to hypothetical new gauge bosons ( named in analogy with the Standard Model W and Z bosons ) .
simplified: Gauge bosons are the particles that are thought to interact with a Higgs field . This theoretical field is believed by many scientists to be responsible for why some gauge bosons â `` like W and Z bosons â `` have mass , while others â `` such as photons â `` do not have mass.