Crossing two-component dark matter models and implications for 511 keV $γ$-ray and XENON1T excesses

Abstract

We study scalar and fermionic crossing two-component dark matter (C2CDM) models with U (1) X dark gauge symmetry. This U (1) X gauge symmetry is broken via the dark Higgs mechanism of a dark Higgs field Φ and the dark photon becomes massive. On the other hand, the same dark Higgs field Φ also serves as a bridge between each component of two DM sectors such that the dark flavor-changing neutral current (DFCNC) interaction between them is induced. Moreover, the mass splitting between these two DM sectors is generated after U (1) X gauge symmetry breaking by nonzero Φ . We discuss the stability of DM candidates and allowed parameter space from the relic density and other constraints in C2CDM models. Some novel signatures with displaced vertices at Belle II are studied. Finally, the possible explanations of 511 keV γ-ray line and XENON1T excess in C2CDM models are discussed.

The effect of multiple cooling channels on the formation of dark compact objects

“…There are also non-composite models where the mass splitting is generated by additional gauge groups, and so diagonal and off-diagonal couplings between χ 1 , χ 2 are generated, see e.g. [51].…”

“…The inclusion of two distinct mass states permits us to study inelastic dissipative processes in a simple framework. This model could be realized in any number of dark matter models frameworks in which tree-level inelastic processes are relevant, which have been extensively studied in [42][43][44][45][46][47][51][52][53]. In this work, we will work with a mass hierarchy where m γ D ≪ δ ≪ m χ 1 .…”

Muon $(g-2)$ and Thermal WIMP DM in ${\rm U(1)}_{L_μ-L_τ} $ Models

“…Here we assume that Q X = 1, and Q Φ is chosen in such a way that there are no gauge invariant operators up to dim-5 that would make the DM X decay into the SM particles, so that DM particle would be stable or long-lived enough [83,84]. This case we call "generic" [85].…”