Light mediators in anomaly free U (1)X models. Part II. Constraints on dark gauge bosons

Abstract

We consider experimental constraints in the MeV region in order to determine the parameter space for the U(1) X extension of the Standard Model, presented in the first part of our work. In particular, we focus on the model UV-completed by cold WIMPs. We conclude that the electron anomalous magnetic moment and the neutrino trident production provide the most stringent bounds to g 2 X ∼ 10 −6 in the mass interval below the di-muon threshold. By allowing the axial-vector coupling of the dark gauge boson Z , the interference effect with the SM gauge bosons may reduce the bounds coming from the neutrino trident production. At the same time, such coupling allows a region of the parameter space already favored both by the relic abundance and by the discrepancy between experimental result and theoretical prediction for the muon anomalous magnetic moment. We emphasize that light-Z interactions, non-universal for the two first lepton families, necessarily create a difference in the proton charge radius measured in the Lamb shift of the e-hydrogen and µ-hydrogen. Finally, we determine the effects of the new gauge boson on the forward-backward asymmetry in e + e − →f f , f = µ, τ , and on the leptonic decays M → jν j l + l − , where M = π, K, D, D s , B and j, l = e, µ.

Low scale U(1)X gauge symmetry as an origin of dark matter, neutrino mass and flavour anomalies

“…In a similar direction, studies are available in the literature with a heavy U(1) X gauge boson [27][28][29][30][31][32][33][34][35]. While such models with heavy U(1) X gauge boson have been extensively studied, there have been very few studies on low mass regions [36][37][38][39][40]. However, our working model is very much different compared to the one discussed in the references mentioned above and we also correlate the flavour anomalies with origin of neutrino mass and dark matter.…”

Probing new physics scenarios of muon g − 2 via J/ψ decay at BESIII

“…Probing such light scalar and vector particles have also been discussed in context of other decay modes in refs. [11][12][13] in context of specific U(1) extensions of the SM.…”

Supersymmetric gauged U(1)Lμ−LτBanerjee1, Byakti2, Roy3 2018Phys. Rev. D313180View full textAdd to dashboardCite

“…The issue of the muon and electron anomalous magnetic moment have been addressed with an additional Z gauge boson [10][11][12][13][14][15][16][17][18]. However, the Z contribution as the singular source of the lepton (g − 2) is always of the same sign unless the nature of the gauge bosonlepton couplings switch over generations [19].…”