Pseudoscalar-portal Dark Matter in the Light of AMS-02 positron excess
Year: 2020
Type: preprint
Abstract: We revisit dark matter annihilation as an explanation of the positron excess reported recently by the AMS-02 satellite-borne experiment. To this end, we propose a particle dark matter model by considering a Two Higgs Doublet Model (THDM) extended with an additional pseudoscalar singlet and a singlet fermion. The additional (light) pseudoscalar singlet mixes with the pseudoscalar inherent in the THDM, and the singlet fermion, which is the dark matter candidate, annihilates via the pseudoscalar portal. The dark matter candidate is made leptophilic by choosing the muon-specific THDM and a suitable high value of $\tan\beta$ explaining the muon g-2 anomaly. After establishing the viability of the singlet fermion to be a dark matter candidate, we calculate the positron excess coming from its annihilation to a pair of heavy Higgs bosons which primarily decay to muons. Incorporating the Sommerfeld effect caused by the light pseudoscalar and with an appropriate boost factor, we find that our proposed model can satisfactorily explain the positron fraction as well as the positron spectrum data.
Source: arXiv (Cornell University)
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3011069131