Viability of boosted light dark matter in a two-component scenario

Publications

Viability of boosted light dark matter in a two-component scenario

Year : 2025

Publisher : American Physical Society

Source Title : Physical Review D

Document Type :

Abstract

We study the boosted dark matter scenario in a two-component model. We consider a neutrinophilic two-Higgs doublet model, which consists of one extra Higgs doublet and a light right-handed neutrino. This model is extended with a light (∼10 MeV) singlet scalar dark matter (DM) φ3, which is stabilized under an extra dark Z2DM symmetry and can only effectively annihilate through the CP even scalar H. Although the presence of a light scalar H modifies the oblique parameters to put tight constraints on the model, the introduction of vectorlike leptons can potentially salvage the issue. The vectorlike doublet N and singlet χ are also stabilized through dark Z2DM symmetry. The lightest vectorlike mass eigenstate (χ1∼100 GeV) is the second DM component of the model. Individual scalar and fermionic DM candidates have Higgs/Z mediated annihilation, restricting the fermion DM in a narrow mass region while a somewhat broader mass region is allowed for the scalar DM. However, when two DM sectors are coupled, the annihilation channel χ1χ1→φ3φ3 opens up. As a result, the fermionic relic density decreases, and paves the way for a broader fermionic DM mass region with underabundant relic: a region of [30-65] GeV compared to a narrower [40-50] GeV window for the single component case. On the other hand, the light DM φ3 acquires significant boost from the annihilation of χ1, causing a dilution in the resonant annihilation of φ3. This in turn increases the scalar DM relic, allowing for a smaller mass region compared to the individual case. The exact and underabundant relic is achievable in a significant parameter space of the two-component model where the total DM relic is mainly dominated by the fermionic DM contribution. The scalar DM is found to be subdominant or equally dominant (∼30%–80% of total DM) with significant boost, which can be detected in experiments.