Fermionic dark matter via UV and IR freeze-in and its possible X-ray signature

Understand

Non-observation of any dark matter signature at various direct detection experiments over the last decade keeps indicating that immensely popular WIMP paradigm may not be the actual theory of particle dark matter.

• Non-thermal dark matter produced through freeze-in is an attractive proposal, naturally explaining null results by virtue of its feeble couplings with the Standard Model (SM) particles.
• We consider a minimal extension of the SM by two gauge singlet fields namely, a $\mathbb{Z}_2$-odd fermion $\chi$ and a pseudo scalar $\tilde{\phi}$, where the former has interactions with the SM particles only at dimension five level and beyond.
• This introduces natural suppression in the interactions of $\chi$ by a heavy new physics scale $\Lambda$ and forces $\chi$ to be a non-thermal dark matter candidate.