We propose a simple extension of the standard model (SM) by adding an extra $U(1)$ symmetry which is hidden from the SM sector. Such a hidden $U(1)$ has not been considered before, and its existence at the TeV scale can be explored at the LHC. This hidden $U(1)$ does not couple directly to the SM particles, and couples only to new $SU(2{)}_L$ singlet exotic quarks and singlet Higgs bosons, and is broken at the TeV scale. The dominant signals at the high-energy hadron colliders are multilepton and multi-$b$-jet final states with or without missing energy. We calculate the signal rates as well as the corresponding standard model background for these final states. A very distinctive signal is 6 high $p_T$ $b$-jets in the final state with no missing energy. For a wide range of the exotic quarks masses the signals are observable above the background at the LHC.

• Received 19 July 2010

DOI:https://doi.org/10.1103/PhysRevD.82.055021