An anomalous extra Z prime from intersecting branes with Drell–Yan and direct photons at the LHC Original Research Article

We quantify the impact of gauge anomalies at the Large Hadron Collider by studying the invariant mass distributions in Drell–Yan and in double prompt photon, using an extension of the Standard Model characterized by an additional anomalous image derived from intersecting branes. The approach is rather general and applies to any anomalous Abelian gauge current. Anomalies are cancelled using either the Wess–Zumino mechanism with suitable Peccei–Quinn-like interactions and a Stückelberg axion, or by the Green–Schwarz mechanism. We compare predictions for the corresponding extra Z prime to anomaly-free realizations such as those involving image. We identify the leading anomalous corrections to both channels, which contribute at higher orders, and compare them against the next-to-next-to-leading order (NNLO) QCD background. Anomalous effects in these inclusive observables are found to be small, below the size of the typical QCD corrections quantified by NNLO K-factors. Measurements at the LHC on the Z resonance in leptoproduction will be able to exclude a class of these models for variations of the cross section at the level of 4%, which is obtained at larger values of the anomalous coupling (image). However, If they are not excluded, their anomalous nature is unlikely to be resolved with an inclusive NNLO analysis performed in these key processes.