Implications of unitarity and gauge invariance for simplified dark matter models

By Felix Kahlhoefer, K. Schmidt-Hoberg, T. Schwetz, S. Vogl. 2015

255 citations recorded by the source corpus.

A bstractWe show that simplified models used to describe the interactions of dark matter with Standard Model particles do not in general respect gauge invariance and that perturbative unitarity may be violated in large regions of the parameter space. The modifications necessary to cure these inconsistencies may imply a much richer phenomenology and lead to stringent constraints on the model. We illustrate these observations by considering the simplified model of a fermionic dark matter particle and a vector mediator. Imposing gauge invariance then leads to strong constraints from dilepton resonance searches and electroweak precision tests. Furthermore, the new states required to restore perturbative unitarity can mix with Standard Model states and mediate interactions between the dark and the visible sector, leading to new experimental signatures such as invisible Higgs decays. The resulting constraints are typically stronger than the ‘classic’ constraints on DM simplified models such as monojet searches and make it difficult to avoid thermal overproduction of dark matter.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/190e4c9314b071e2e9da8c68974c5d29b98d682b

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Citations in the corpus

WIMP dark matter candidates and searches—current status and future prospects (2017, background): “It has been pointed out that gauge invariance and perturbative unitarity need to be carefully taken into account when constructing simplified models of DM interactions [222, 223].”
Recommendations on presenting LHC searches for missing transverse energy signals using simplified s-channel models of dark matter (2016, background): “However, it was shown in [31,38] that perturbative unitarity is violated in the axial-vector model due to the DM Yukawa coupling becoming non-perturbative, even for perturbative values of gq and gDM, if mDM is significantly larger than Mmed.”
Simplified dark matter models with two Higgs doublets: I. Pseudoscalar mediators (2017, background): “The existing LEP and LHC measurements of the Z-boson and Higgs-boson properties however severely restrict the corresponding mixing angles, and as a result classic ET,miss searches like mono-jets are typically not the leading collider constraints in this class of simplified DM models [6, 10, 11].”
Search for dark matter and other new phenomena in events with an energetic jet and large missing transverse momentum using the ATLAS detector (2017, background): “Perturbative unitarity is violated in the parameter region defined by mχ > √ π/2 mZA [92].”
The waning of the WIMP? A review of models, searches, and constraints (2017, background): “bative unitarity unless new degrees of freedom, like a dark Higgs [162], are added to cure the pathological behavior of the theory.”