Single-top final states as a probe of top-flavoured dark matter models at the LHC

Abstract

Models incorporating flavoured dark matter provide an elegant solution to the dark matter problem, evading the tight LHC and direct direction constraints on simple WIMP models. In Dark Minimal Flavour Violation, a simple framework of flavoured dark matter with new sources of flavour violation, the constraints from thermal freeze-out, direct detection experiments, and flavour physics create well-defined benchmark scenarios for these models. We study the LHC phenomenology of four such scenarios, focusing on final states where a single top quark is produced accompanied by no jets, one jet from the fragmentation of light quarks or a b-tagged jet. For each of these signatures we develop a realistic LHC analysis, and we show that the proposed analyses would increase the parameter space coverage for the four benchmarks, compared to existing flavour-conserving LHC analyses. Finally we show the projected discovery potential of the considered signatures for the full LHC statistics at 14 TeV, and for the High Luminosity LHC.

Charming ALPs

“…when there is a sizeable coupling of the ALP with the top quark, provided one interprets 1/Γ as the total lifetime. 9 In the cases where a → 3π dominates, bounds from 4 He overproduction -the dominant constraint in this region -will still hold regardless of the changes in the branching ratios, since only a minimal amount of charged pions is enough for this bound to apply. For even larger masses, ALP decays into hadrons will eventually make its lifetime shorter than a second, making nucleosynthesis constraints harmless.…”

Tasting Flavoured Majorana Dark Matter

“…Note that the limits used in [17] to constrain the Dirac version of top-flavoured DM were based on LHC run 1 data with √ s = 8 TeV. Updated bounds resulting from a recast of 136 fb −1 of LHC run 2 data at √ s = 13 TeV were presented in [23]. In this study we will use the same run 2 limits as in [23] to constrain our model of flavoured Majorana DM.…”

“…Updated bounds resulting from a recast of 136 fb −1 of LHC run 2 data at √ s = 13 TeV were presented in [23]. In this study we will use the same run 2 limits as in [23] to constrain our model of flavoured Majorana DM.…”

“…It is also possible that the two intermediate φ bosons decay into two χ particles, one top quark and one light quark, generating the signature tj + / E T , which is also generated in SUSY models with flavour violating squark decays [21,[30][31][32][33][34]. While no dedicated searches for this signature currently exist, it has been shown in [23] to have significant discovery potential in the case of Dirac DM. We expect that similar conclusions also hold in our model, but leave a detailed analysis for future work.…”

“…• Similarly to flavour-violating supersymmetric models [21,22], the model predicts the new benchmark signatures tj + / E T and monotop+ / E T at a significant rate. A dedicated experimental search has been proposed in [23].…”