Dark matter direct detection constraints from gauge bosons loops

While many interactions of dark matter (DM) with the standard model (SM) affect direct detection and LHC searches, there are only a few operators generating annihilation of DM into photons. All of these operators, except four of them, give rise to unsuppressed rates, rendering indirect detection superior to other search strategies. For two of the four effective interactions with velocity-suppressed annihilation cross sections, we identify a new type of loop effect which significantly enhances the associated direct detection rates. As a result, relevant constraints from next-generation direct detection experiments on DM-SM interactions, so far only bounded by the LHC, are obtained.

Figure 1

Examples of Feynman diagrams generating mixing of $O_B$ into $O_y$ (left) and $O_W$ into $O_{\varphi }$ (right). The operator insertions are indicated by squares, while the $SU(2{)}_L\times U(1{)}_Y$ dimension-4 vertices are represented by dots.

Figure 2

Restrictions in the $m_{\chi }\text{−}{C}_B(\mathrm{\Lambda })$ (upper panel) and $m_{\chi }\text{−}{C}_W(\mathrm{\Lambda })$ (lower panel) planes, assuming DM to be Majorana and setting $\mathrm{\Lambda }=300\mathrm{GeV}$. The green curves illustrate the best limits from ${\cancel{E}}_T$ searches at the LHC, while the black dotted lines correspond to the observed value ${\mathrm{\Omega }}_{\chi }{h}^2=0.11$ of the relic density. The colored dashed curves mark the bounds from existing and future direct detections experiments. The currently allowed parameter regions are indicated by yellow shading. The contour lines denote the fraction of the observed relic density obtained from the operator under consideration. For Dirac DM, the bounds on the Wilson coefficients $C_B(\mathrm{\Lambda })$ and $C_W(\mathrm{\Lambda })$ from the LHC, the relic density and direct detection are weaker by factors of $\sqrt{2}$, $2\sqrt{2}$ and 2.