Muon Decay and the Higgs Vaccum Expectation Value

Abstract

The Higgs vacuum expectation value (vev) can be determined experimentally by measuring the muon lifetime. However, this determination can be modified by the introduction of a new virtual particle in the muon decay, for example a Z'. This new massive vector boson can change the mechanism by which the muon decays despite having an expression for the amplitude of the same form as the one predicted by the SM, where the process is mediated by a W boson. These two theories have been matched to the 4-fermion operator from a low-energy Effective Field Theory that describes the physics at low energies, resulting in a correlation between the Higgs vacuum expectation value and the mass of the new particle