Stealth dark matter: Dark scalar baryons through the Higgs portal

Abstract

We present a new model of "Stealth Dark Matter": a composite baryonic scalar of an SU (ND) strongly-coupled theory with even ND ≥ 4. All mass scales are technically natural, and dark matter stability is automatic without imposing an additional discrete or global symmetry. Constituent fermions transform in vector-like representations of the electroweak group that permit both electroweak-breaking and electroweak-preserving mass terms. This gives a tunable coupling of stealth dark matter to the Higgs boson independent of the dark matter mass itself. We specialize to SU (4), and investigate the constraints on the model from dark meson decay, electroweak precision measurements, basic collider limits, and spin-independent direct detection scattering through Higgs exchange. We exploit our earlier lattice simulations that determined the composite spectrum as well as the effective Higgs coupling of stealth dark matter in order to place bounds from direct detection, excluding constituent fermions with dominantly electroweak-breaking masses. A lower bound on the dark baryon mass mB > ∼ 300 GeV is obtained from the indirect requirement that the lightest dark meson not be observable at LEP II. We briefly survey some intriguing properties of stealth dark matter that are worthy of future study, including: collider studies of dark meson production and decay; indirect detection signals from annihilation; relic abundance estimates for both symmetric and asymmetric mechanisms; and direct detection through electromagnetic polarizability, a detailed study of which will appear in a companion paper.

Hadronic and Hadron-Like Physics of Dark Matter

“…In this section, we consider some particular variants of models that extend SM by introducing an additional strong sector with heavy vector-like fermions, hyperquarks (H-quarks), charged under an H-color gauge group [67][68][69][70][71][72][73][74][75][76][77][78]. Depending on H-quark quantum numbers, such models can encompass scenarios with composite Higgs doublets (see e.g., [79]) or a small mixing between fundamental Higgs fields of SM and composite hadron-like states of the new strong sector making the Higgs boson partially composite.…”

Lattice tests of beyond standard model dynamics

“…Not surprisingly, there are lattice studies of composite dark matter models. The literature I know of includes studies of SU (2) gauge theories coupled to N f = 2 flavors of fundamental fermions (Detmold et al, 2014a,b;Hietanen et al, 2014a,b;Lewis et al, 2012) and SU (4) gauge theory with quenched fundamental representation fermions (Appelquist et al, 2014b(Appelquist et al, , 2015a. Most of the work is about the spectroscopy of these systems, mostly their baryon spectroscopy because one is interested in knowing what is likely to be the most stable particle.…”

Observational prospects for gravitational waves from hidden or dark chiral phase transitions

“…Refs. [44][45][46][47][48][49][50]. Similarly, they are introduced in Twin Higgs models [51,52], Hidden Valley theories [53] or vector-like confinement models [54].…”