A complete Effective Field Theory for Dark Matter

Abstract

We present an effective field theory describing the relevant interactions of the Standard Model with an electrically neutral particle that can account for the dark matter in the Universe. The possible mediators of these interactions are assumed to be heavy. The dark matter candidates that we consider have spin 0, 1/2 or 1, belong to an electroweak multiplet with arbitrary isospin and hypercharge and their stability at cosmological scales is guaranteed by imposing a Z 2 symmetry. We present the most general framework for describing the interaction of the dark matter with standard particles, and construct a general non-redundant basis of the gauge-invariant operators up to dimension six. The basis includes multiplets with non-vanishing hypercharge, which can also be viable DM candidates. We give two examples illustrating the phenomenological use of such a general effective framework. First, we consider the case of a scalar singlet, provide convenient semi-analytical expressions for the relevant dark matter observables, use present experimental data to set constraints on the Wilson coefficients of the operators, and show how the interplay of different operators can open new allowed windows in the parameter space of the model. Then we study the case of a lepton isodoublet, which involves co-annihilation processes, and we discuss the impact of the operators on the particle mass splitting and direct detection cross sections. These examples highlight the importance of the contribution of the various nonrenormalizable operators, which can even dominate over the gauge interactions in certain cases.

Phenomenological analysis of multi-pseudoscalar mediated dark matter models

“…Unfortunately, the current results from such experiments yield a uniformly null outcome, as a result of which all that we possess are fairly severe constraints on the parameter space of the more well-motivated models in which the WIMPs are embedded [7][8][9][10][11]. This is all the more reason, therefore, to approach the dark matter problem in a model-independent way, using the framework of either effective field theories (EFTs) [12,13] or simplified models [14][15][16]. Here, we can then try to pinpoint the specific Lorentz structures which are permitted by the existing constraints, rather than delving deep into the intricacies of a specific ultraviolet (UV)-complete model [17].…”

Dark Matter Effective Field Theory and an Application to Vector Dark Matter

“…In a recent work, the authors of Ref. [38] discussed an extension of the SM Effective Field Theory (SMEFT) [39] with spin 0, 1/2 and 1 particles, presenting a general non-redundant basis of gauge-invariant operators up to dimension six. The DM fields are assumed to transform as electroweak multiplets with arbitrary weak isospin and hypercharge, and to respect a Z 2 symmetry under which DM particles are odd.…”

Mono-γ production of a dark vector at future e + e − colliders*

“…In general, DM can be a scalar [14][15][16][17][18][19][20][21], fermion (Dirac or Majorana) [17][18][19][20][21][22][23][24][25][26], or vector state [18][19][20][27][28][29][30][31].…”