UV completion of an axial, leptophobic, Z′

The Z-portal is one of most popular and well-explored scenarios of dark matter (DM). To avoid the strong constraints coming from dilepton resonance searches at the LHC and direct detection of DM, it is usually required that in addition to being leptophobic, the Z is axially coupled to either the (fermionic) DM or the standard model (SM) quarks. The first possibility has been extensively studied both in the context of simplified model and ultraviolet (UV) complete scenarios. However, the studies on the second possibility are largely confined to simplified models only. Here, we construct the minimal UV completion of these models satisfying both the criteria of leptophobia and purely axial Z-quark coupling. The anomaly cancellation conditions demand highly non-trivial structures, not only in the dark sector, but also in the Higgs sector. We also discuss the main phenomenological implications of the UV completion, in particular the existence of novel constraints associated to the Z−Z mixing, and examine the thermal DM production.This work has been partially supported by MINECO, Spain, under contract FPA2016-78022-P and Centro de excelencia Severo Ochoa Program under grant SEV-2016-059