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 nontrivial 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.