Predicted Signatures at the LHC from U(1) Extensions of the Standard Model

Abstract

We discuss the U (1) X extensions of the standard model with focus on the Stueckelberg mechanism for mass growth for the extra U (1) X gauge boson. The assumption of an axionic connector field which carries dual U (1) quantum numbers, i.e., quantum numbers for the hypercharge U (1) Y and for the hidden sector gauge group U (1) X , allows a non-trivial mixing between the mass growth for the neutral gauge vector bosons in the SU (2) L × U (1) Y sector and the mass growth for the vector boson by the Stueckelberg mechanism in the U (1) X sector. This results in an extra Z ′ which can be very narrow, but still detectable at the Large Hadron Collider (LHC). The U (1) X extension of the minimal supersymmetric standard model is also considered and the role of the Fayet-Illiopoulos term in such an extension discussed. The U (1) X extensions of the SM and of the MSSM lead to new candidates for dark matter.