LFV couplings of the extra gauge bosonZ′and leptonic decay and production of pseudoscalar mesons

Abstract

Considering the constraints of the lepton flavor violating (LFV) processes μ → 3e and τ → 3μ on the LFV couplings Z i j , in the contexts of the E 6 models, the left-right (LR) models, the "alternative" left-right (ALR) models and the 331 models, we investigate the contributions of the extra gauge boson Z to the decay rates of the processes i → j ν ν , τ → μP and P → μe with P = π 0 , η and η . Our numerical results show that the maximal values of the branching ratios for these processes are not dependent on the Z mass M Z at leader order. The extra gauge boson Z X predicted by the E 6 models can make the maximum value of the branching ratio Br(τ → μν ν ) reach 1.1 × 10 −7 . All Z models considered in this paper can produce significant contributions to the process τ → μP . However, the value of Br(P → μe) is far below its corresponding experimental upper bound.

Flavor violation in chromo- and electromagnetic dipole moments induced by Z′ gauge bosons and a brief revisit of the Standard Model

“…The flavor violation (FV) issue has allowed us to relate the hypothetical Z 0 particle with several processes such as single top production [3,4], the D 0 −D 0 mixing system [4], the b 0 q −b 0 q mixing system [16], lepton flavor-violating decays [5,11,17,18], etc. In this way, by using the most general renormalizable Lagrangian that includes FV mediated by a new neutral massive gauge boson, we will estimate the impact of FCNC on the electromagnetic dipole moments of the tau lepton and the chromoelectromagnetic dipole moments of the top quark, resorting to different grand unification models (GUT) with extended current sectors [3,19].…”

Flavor violation in chromo- and electromagnetic dipole moments induced by $Z^\prime$ gauge bosons and a brief revisit of the Standard Model

“…The flavor violation (FV) issue has allowed us to relate the hypothetical Z ′ particle with several processes such as single top production [3,4], the D 0 − D0 mixing system [4], the b 0 q − b0 q mixing system [16], lepton flavor-violating decays [5,11,17,18], etc. In this way, by using the most general renormalizable Lagrangian that includes FV mediated by a new neutral massive gauge boson, we will estimate the impact of FCNC on the electromagnetic dipole moments of the tau lepton and the chromoelectromagnetic dipole moments of the top quark, resorting to different grand unification models (GUT) with extended current sectors [3,19].…”

New gauge bosonZ′and lepton flavor violating decays and production of vector mesons

“…Reference [12] has shown that the most stringent constraints on the LFV coupling constants g µe L,R , g τ e L,R and g τ µ L,R come from the LFV decays µ → 3e, τ → 3e and τ → 3µ, respectively. Reference [13] has given the constraints on the coupling factors g ij L,R for several Z ′ models and further calculated their contributions to the LFV processes P → µe and τ → µP with the pseudoscalar meson…”