Electron and muon g-2 anomalies in general flavor conserving two-Higgs-doublet models

Abstract

In general two-Higgs-doublet models (2HDMs) without scalar flavor changing neutral couplings (SFCNC) in the lepton sector, the electron, muon, and tau interactions can be decoupled in a robust framework, stable under renormalization group evolution. In this framework, the breaking of lepton flavor universality (LFU) goes beyond the mass proportionality, opening the possibility to accommodate in a simple manner a different behavior among charged leptons. We analyze simultaneously the electron and muon (g-2) anomalies in the context of these general flavor conserving models in the leptonic sector (gℓFC). We consider two different models, I-gℓFC and II-gℓFC, in which the quark Yukawa couplings coincide, respectively, with the ones in type I and in type II 2HDMs. We find two types of solutions that fully reproduce both (g-2) anomalies, and which are compatible with experimental constraints from LEP and LHC, from LFU, from flavor and electroweak physics, and with theoretical constraints in the scalar sector. In the first type of solution, all the new scalars have masses in the 1-2.5 TeV range, the vacuum expectation values (vevs) of both doublets are quite similar in magnitude, and both anomalies are dominated by two loop Barr-Zee contributions. This solution appears in both models. There is a second type of solution, where one loop contributions are dominant in the muon anomaly, all new scalars have masses below 1 TeV, and the ratio of vevs is in the range 10-100. The second neutral scalar H is the lighter among the new scalars, with a mass in the 210-390 GeV range while the pseudoscalar A is the heavier, with a mass in the range 400-900 GeV. The new charged scalar H± is almost degenerate either with the scalar or with the pseudoscalar. This second type of solution only appears in the I-gℓFC model. Both solutions require the soft breaking of the Z2 symmetry of the Higgs potential.