Triplet-quadruplet dark matter

Abstract

We explore a dark matter model extending the standard model particle content by one fermionic SU(2) L triplet and two fermionic SU(2) L quadruplets, leading to a minimal realistic UV-complete model of electroweakly interacting dark matter which interacts with the Higgs doublet at tree level via two kinds of Yukawa couplings. After electroweak symmetry-breaking, the physical spectrum of the dark sector consists of three Majorana fermions, three singly charged fermions, and one doubly charged fermion, with the lightest neutral fermion χ 0 1 serving as a dark matter candidate. A typical spectrum exhibits a large degree of degeneracy in mass between the neutral and charged fermions, and we examine the one-loop corrections to the mass differences to ensure that the lightest particle is neutral. We identify regions of parameter space for which the dark matter abundance is saturated for a standard cosmology, including coannihilation channels, and find that this is typically achieved for m χ 0 1 ∼ 2.4 TeV. Constraints from precision electroweak measurements, searches for dark matter scattering with nuclei, and dark matter annihilation are important, but leave open a viable range for a thermal relic.

Long live the Higgs portal!

“…In this regime the three-body decays χ + → χ + ν and χ + → χ +hadrons dominate the decay rate. In the scalar and pseudo-scalar scenarios, three-body decays proceed through vector currents (7) and axial-vector currents (11), respectively. For ∆m c M W , m c , the partial width of the leptonic decay χ + → χ + ν is given by [46] 7…”

Exploring triplet-quadruplet fermionic dark matter at the LHC and future colliders

“…[26,[57][58][59]. In some parameter regions with y 1 y 2 < 0, the condition of m χ 0 1 < m χ ± 1 satisfied at tree level may not hold at one-loop level [26]. Such parameter regions should be excluded, since there is no available DM candidate.…”

“…Thus, a dark sector with singlet and doublet fermions [15-18, 20, 23, 27-30, 36], or with doublet and triplet fermions [21,29,36,37], is analogous to the EW sector of SUSY models in special limits, which has been well studied in the literature for decades. A more complicated case with triplet and quadruplet fermions [26,29], however, cannot be regarded as a limit of the SUSY electroweak sector. Thus, we may expect that the phenomenology could be quite different.…”

“…Besides, if χ 0 1 consists of the pure triplet component or the pure quadruplet components, the mass splitting between χ ± 1 and χ 0 1 would be ∼ α 2 m W sin 2 (θ W /2) = 167 MeV, only induced by loop effects [8,9,26]. Consequently, the charged fermion χ ± 1 has a macroscopic lifetime, and can travel a short distance in the inner detector before decaying to χ 0 1 and a very soft, unlikely detected π ± In the TQDM model [26,29], the dark sector involves one colorless left-handed Weyl triplet T and two colorless left-handed Weyl quadruplets Q 1 and Q 2 obeying the following SU (2) L × U (1) Y gauge transformations:…”

Pseudo-Nambu-Goldstone dark matter and two-Higgs-doublet models

“…One possibility is that there are some blind spots with particular parameters leading to the suppression of the DM couplings relevant to direct detection [7][8][9][10][11]. Additionally, the relevant DM couplings could vanish due to special symmetries [12][13][14][15][16][17]. Moreover, DM-nucleon scattering mediated by pseudoscalars can evade direct detection constraints [18][19][20][21][22][23][24].…”