The Search for Extra Neutral Currents at the LHC: QCD and Anomalous Gauge Interactions

Understand

Extensions of the Standard Model with extra neutral currents due to additional anomalous abelian gauge factors are considered.

• We summarize the main features of the effective action associated to these theories.
• They are characterized by an axion-like particle (the {\em axi-higgs}) which can be (almost) massless, with its mass generated non-perturbatively in the QCD vacuum as for an ordinary Peccei-Quinn axion, but that can also mix with the scalars of the Higgs sector, becoming a heavy axion.
• We briefly describe the interplay between the electroweak and the QCD sectors in these types of theories, which emerge either from special vacua of string/brane theory; from partial decoupling of a heavier fermion sector or from an anomaly inflow in the context of models with extra dimensions.