The two-loop contributions to muon MDM in $U(1)_X$ SSM

Abstract

The MSSM is extended to the U (1) X SSM, whose local gauge group isTo obtain the U (1) X SSM, we add the new superfields to the MSSM, namely: three Higgs singlets η, η, Ŝ and right-handed neutrinos νi . It can give light neutrino tiny mass at the tree level through the seesaw mechanism. The study of the contribution of the two-loop diagrams to the MDM of muon under U (1) X SSM provides the possibility for us to search for new physics. In the analytical calculation of the loop diagrams (one-loop and two-loop diagrams), the effective Lagrangian method is used to derive muon MDM. Here, the considered two-loop diagrams include Barr-Zee type diagrams and rainbow type two-loop diagrams, especially Z-Z rainbow twoloop diagram is taken into account. The obtained numerical results can reach 7.4 × 10 −10 , which can remedy the deviation between SM prediction and experimental data to some extent.