Dark matter bound state formation in fermionic Z2 DM model with light dark photon and dark Higgs boson

Inelastic dark matter is an interesting scenario for light thermal dark matter which is fully consistent with all cosmological probes as well as direct and indirect dark matter detection. The required mass splitting between dark matter χ1 and its heavier twin χ2 is naturally induced by a dark Higgs field which also provides a simple mechanism to give mass to the dark photon A′ present in the setup. The corresponding dark Higgs boson h′ is naturally the lightest dark sector state and therefore decays into Standard Model particles via Higgs mixing. In this work we study signatures with displaced vertices and missing momentum at Belle II, arising from dark Higgs particles produced in association with dark matter. We find that Belle II can be very sensitive to this scenario, in particular if a displaced vertex trigger is available in the near future.

Section: Jhep04(2021)146mentioning

confidence: 99%

Long-lived dark Higgs and inelastic dark matter at Belle II

Duerr

Garcia-Cely

Hearty

et al. 2021

“…The importance of monopole BSF processes in a broken gauge phase due to the Goldstone boson equivalence theorem was previously pointed out in ref. [52].…”

Section: Jhep08(2021)069mentioning

confidence: 99%

Bound states of WIMP dark matter in Higgs-portal models. Part II. Thermal decoupling

Oncala

Petraki

2021

The Higgs doublet can mediate a long-range interaction between multi-TeV particles coupled to the Weak interactions of the Standard Model, while its emission can lead to very rapid bound-state formation processes and bound-to-bound transitions. Using the rates calculated in a companion paper, here we compute the thermal decoupling of multi-TeV WIMP dark matter coupled to the Higgs, and show that the formation of metastable dark matter bound states via Higgs-doublet emission and their decay decrease the relic density very significantly. This in turn implies that WIMP dark matter may be much heavier than previously anticipated, or conversely that for a given mass, the dark matter couplings to the Higgs may be much lower than previously predicted, thereby altering the dark matter phenomenology. While we focus on a minimal singlet-doublet model in the coannihilation regime, our calculations can be extended to larger multiplets where the effects under consideration are expected to be even more significant.

“…These results build on the work of ref. [1] that showed the importance of bound-state formation via emission of a scalar charged under a symmetry (see also [47]), as well as the work of refs. [2,3] that demonstrated the long-range effect of the Higgs boson between TeV-scale particles.…”

Section: Jhep06(2021)124mentioning

confidence: 88%

“…[28]. Here we simply note that, by virtue of the Goldstone boson equivalence theorem, BSF via Higgs-doublet emission remains important in the broken electroweak phase, where it occurs via emission of the Higgs boson and the longitudinal components of the Weak gauge bosons [47].…”

Section: Introductionmentioning

confidence: 99%

Bound states of WIMP dark matter in Higgs-portal models. Part I. Cross-sections and transition rates

Oncala

Petraki

2021

We investigate the role of the Higgs doublet in the thermal decoupling of multi-TeV dark matter coupled to the Weak interactions of the Standard Model and the Higgs. The Higgs doublet can mediate a long-range force that affects the annihilation processes and binds dark matter into bound states. More importantly, the emission of a Higgs doublet by a pair of dark matter particles can give rise to extremely rapid monopole bound-state formation processes and bound-to-bound transitions. We compute these effects in the unbroken electroweak phase. To this end, we consider the simplest renormalisable fermionic model, consisting of a singlet and a doublet under SUL(2) that are stabilised by a ℤ2 symmetry, in the regime where the two multiplets coannihilate. In a companion paper, we use the results to show that the formation of metastable bound states via Higgs-doublet emission and their decay decrease the relic density very significantly.