Search

Abstract A flavor-dependent model (FDM) is proposed in this work. The model extends the Standard Model by an extra $$U(1)_F$$ U ( 1 ) F local gauge group, two scalar doublets, one scalar singlet and two right-handed neutrinos, where the additional $$U(1)_F$$ U ( 1 ) F charges are related to the particles’ flavor. The new fermion sector in the FDM can explain the flavor mixings puzzle and the mass hierarchy puzzle simultaneously, and the nonzero Majorana neutrino masses can be obtained naturally by the Type I see-saw mechanism. In addition, the B meson rare decay processes $${\bar{B}} \rightarrow X_s\gamma ,$$ B ¯ → X s γ , $$B_s^0 \rightarrow \mu ^+\mu ^-,$$ B s 0 → μ + μ - , the top quark rare decay processes $$t\rightarrow ch,$$ t → c h , $$t\rightarrow uh$$ t → u h and the $$\tau $$ τ lepton flavor violation processes $$\tau \rightarrow 3e,$$ τ → 3 e , $$\tau \rightarrow 3\mu ,$$ τ → 3 μ , $$\mu \rightarrow 3e$$ μ → 3 e predicted in the FDM are analyzed.

People extend the MSSM with the local gauge group U(1)X to obtain the U(1)XSSM. In the framework of the U(1)XSSM, we study the flavor transition process b→sγ with the mass insertion approximation (MIA). By the MIA method and some reasonable parameter assumptions, we can intuitively find the parameters that have obvious effect on the analytic results of the flavor transition process b→sγ. By means of the influences of different sensitive parameters, we can obtain reasonable results to better fit the experimental data.

In this paper, we study the lepton flavor violating decays of the lj→liγγ (j=2, 3; i=1, 2) processes under the U(1)XSSM. The U(1)XSSM is the addition of three singlet new Higgs superfields and right-handed neutrinos to the minimal supersymmetric standard model (MSSM). Based on the latest experimental constraints of lj→liγγ, we analyze the effects of different sensitive parameters on the results and made reasonable predictions for future experimental development. Numerical analysis shows that many parameters have a greater or lesser effect on lepton flavor violation (LFV), but the main sensitive parameters and sources leading to LFV are the non-diagonal elements involving the initial and final leptons. This work could provide a basis for the discovery of the existence of new physics (NP).