U(1)Lμ-Lτ breaking phase transition, muon g–2, dark matter, collider, and gravitational wave

Combining the dark matter and muon g-2 anomaly,we study the U(1)Lμ-Lτbreaking phase transition,gravitational wave spectra,and direct detection at the LHC in an extra U(1)Lμ-Lτgauge symmetry extension of the standard model.The new fields include vector-like leptons(E1,E2,N),the U(1)Lμ-Lτbreaking scalar S,and the gauge boson Z’,as well as the dark matter candidate XI and its heavy partner XR.A joint explanation of the dark matter relic density and muon g-2 anomaly excludes the region where both min(mE1,mE2,mN,mXR)and min(mZ’,mS)are much larger than mXI.In the parameter space accommodating the DM relic density and muon g-2 anomaly,the model can achieve a first-order U(1)Lμ-Lτbreaking phase transition,whose strength is sensitive to the parameters of the Higgs potential.The corresponding gravitational wave spectra can reach the sensitivity of UDECIGO.In addition,the direct searches at the LHC impose stringent bounds on the mass spectra of the vector-like leptons and dark matter.