Charged composite scalar dark matter

Abstract

Abstract:We consider a composite model where both the Higgs and a complex scalar χ, which is the dark matter (DM) candidate, arise as light pseudo Nambu-Goldstone bosons (pNGBs) from a strongly coupled sector with TeV scale confinement. The global symmetry structure is SO(7)/SO(6), and the DM is charged under an exact U(1) DM ⊂ SO(6) that ensures its stability. Depending on whether the χ shift symmetry is respected or broken by the coupling of the top quark to the strong sector, the DM can be much lighter than the Higgs or have a weak-scale mass. Here we focus primarily on the latter possibility. We introduce the lowest-lying composite resonances and impose calculability of the scalar potential via generalized Weinberg sum rules. Compared to previous analyses of pNGB DM, the computation of the relic density is improved by fully accounting for the effects of the fermionic top partners. This plays a crucial role in relaxing the tension with the current DM direct detection constraints. The spectrum of resonances contains exotic top partners charged under the U(1) DM , whose LHC phenomenology is analyzed. We identify a region of parameters with f = 1.4 TeV and 200 GeV m χ 400 GeV that satisfies all existing bounds. This DM candidate will be tested by XENON1T in the near future.

Dark matter shifts away from direct detection

“…Our discussion is phrased within a low-energy effective field theory (EFT), but as already stated we support our parameter choices with concrete examples that arise in the composite Higgs model based on the SO(7)/SO(6) symmetry breaking pattern [5]. This construction can yield each of the three above scenarios depending on the region of parameters one focuses on, and is therefore well suited as theory backdrop.…”

“…where π is the GB vector [26]. This redefinition has customarily been adopted in studies of the SO(6)/SO (5) and SO(7)/SO(6) models because in the basis of Eq. (7), which also coincides with the SILH basis [27] when restricted to Higgs interactions, the scalar potential is a simple polynomial and the vacuum expectation value (VEV) of the Higgs is equal to v 246 GeV.…”

“…The idea that the Higgs may arise as a composite pseudo Nambu-Goldstone boson (pNGB) from a new strongly-interacting sector provides one of the best-motivated solutions to the naturalness problem of the weak scale [1,2]. The minimal realistic model [3] is based on a strong sector with global symmetry G = SO (5), whose spontaneous breaking to H = SO (4) at scale f ∼ TeV yields four real pNGBs, identified with the components of the Standard Model (SM)-like Higgs doublet H.…”

“…DM shift symmetry unbroken by SM fermion couplings. It is possible to embed all SM quarks into spurions that preserve the DM shift symmetry [4,5]. In this case some beyond-the-SM source of explicit breaking is required, in order to generate a mass for the DM.…”

The minimal simple composite Higgs model

“…The elementary fermions are embedded in the representations of table 1, and called ψ i , as in Eq. (12).…”