Abstract
Pseudo Nambu-Goldstone bosons (pNGBs) are attractive dark matter (DM) candidates, since they couple to the Standard Model (SM) predominantly through derivative interactions. Thereby they naturally evade the strong existing limits inferred from DM direct detection experiments. Working in an effective field theory that includes both derivative and non-derivative DM-SM operators, we perform a detailed phenomenological study of the Large Hadron Collider reach for pNGB DM production in association with top quarks. Drawing on motivated benchmark scenarios as examples, we compare our results to other collider limits as well as the constraints imposed by DM (in) direct detection experiments and the relic abundance. We furthermore explore implications on the viable parameter space of pNGB DM. In particular, we demonstrate that DM direct detection experiments become sensitive to many pNGB DM realisations once loop-induced interactions are taken into account. The search strategies and pNGB DM benchmark models that we discuss can serve as a starting point for dedicated experimental analyses by the ATLAS and the CMS collaborations.
Highlights
Freeze-out can yield the observed relic density for a dark matter (DM) mass of the order of 100 GeV, while the current severe limits of DM direct detection experiments are naturally evaded
Through loops such operators lead to a j+ETmiss signal, and we study the limits on the parameter space of the Pseudo Nambu-Goldstone bosons (pNGBs) DM effective field theory that are imposed by the corresponding monojet searches
In addition to the analysis strategy described in detail above, we have studied the sensitivity of the fully-leptonic signal regions SRt3 of [36] and SR2-body of [48], the semileptonic signal region DM of [47] and the fully-hadronic signal regions SRt1 and SRt2 of [36] and SRA-TT of [81] to the parameter space of the pNGB DM effective field theory
Summary
Throughout this article we will consider theories in which both the SM Higgs doublet H and the DM candidate χ arise as light pNGBs from a strongly-coupled sector. We mention that under the assumption that the cancellation of gauge anomalies only depends on the SM fermion representations and not on the structure of the pNGB DM effective field theory (in particular the coefficients dψ in (2.1)), the current-current type DM-top operator does not lead to a j + ETmiss signal In practice this requires one to introduce local counterterms that cancel the anomalous contributions in the five-point diagrams like the one shown on the right-hand side in figure 2 — see [49,50,51] for related discussions of gauge anomalies in the context of the so-called SMEFT. Since we envisage that (2.1) describes new-physics scenarios in which the full SM gauge symmetry is preserved, a matching calculation in the full theory will always result in the required anomaly cancellation, and a cancellation of the current-current type contributions to the mono-jet signature for any value of the parameters dψ
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
