Flavored dark matter, and its implications for direct detection and colliders

Abstract

We consider theories where the dark matter particle carries flavor quantum numbers, and has renormalizable contact interactions with the Standard Model fields. The phenomenology of this scenario depends sensitively on whether dark matter carries lepton flavor, quark flavor or its own internal flavor quantum numbers. We show that each of these possibilities is associated with a characteristic type of vertex, has different implications for direct detection experiments and gives rise to distinct collider signatures. We find that the region of parameter space where dark matter has the right abundance to be a thermal relic is in general within reach of current direct detection experiments. We focus on a class of models where dark matter carries tau flavor, and show that the collider signals of these models include events with four or more isolated leptons and missing energy. A full simulation of the signal and backgrounds, including detector effects, shows that in a significant part of parameter space these theories can be discovered above Standard Model backgrounds at the Large Hadron Collider. We also study the extent to which flavor and charge correlations among the final state leptons allows models of this type to be distinguished from theories where dark matter couples to leptons but does not carry flavor.

Signatures of top flavored dark matter

“…If one pursues the alternative guiding principle of looking for a connection between DM and matter particles in the SM, one is then led to the possibility that DM itself may transform nontrivially under flavor symmetries. It is therefore worthwhile to consider classes of models with "Flavored Dark Matter" (FDM) [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], to look for universal features of such models, and to study whether there exist experimental signatures that may be used to distinguish FDM from more traditional models of DM, such as a neutralino in a supersymmetric setup. It is even possible that this line of inquiry may yield new insights in searching for the origin of the SM flavor structure.…”

“…[5]. In particular, the FDM models of phenomenological interest contain a local interaction that couples the DM flavor multiplet to a SM matter field via a mediator, which in the most minimal setup is a flavor singlet.…”

“…For quark flavored DM, direct detection bounds can be severe if χ is coupled to the light quarks, because tree-level φ exchange leads to a large cross section for χ scattering off of nuclei [5]. On the other hand, when χ couples to a third generation quark, the dominant process for χ-nucleus scattering arises at loop level, and direct detection bounds are less constraining.…”

“…We will use the conventions of ref. [5], in particular, we will take the DM multiplet to transform in the (anti-)fundamental representation of U (3) u c . The Lagrangian contains the FDM interaction…”

“…The scenario of lepton-flavored DM has been studied in the literature [5,[15][16][17] and shown to have many interesting features, including the possibility of having an asymmetry between the DM and its antiparticle, generated during high-scale leptogenesis. For quark flavored DM, direct detection bounds can be severe if χ is coupled to the light quarks, because tree-level φ exchange leads to a large cross section for χ scattering off of nuclei [5].…”