 Of these, the W-boson has either a positive or negative electric charge, and mediates neutrino absorption and emission by or with an electrically charged particle.During these processes, the W-boson induces electron or positron emission or absorption, or changing the flavour of a quark as well as its electrical charge.By contrast, the Z particle is electrically neutral, and exchange of a Z-boson leaves the interacting particles’ quantum numbers unaffected, except for a transfer of momentum, spin, and energy.