Discovering dark matter through flavor violation at the LHC

We show that the discovery channel for dark matter (DM) production at colliders can be through flavor violating interactions resulting in a novel signature of a single top and large missing transverse energy. We discuss several examples where the production of DM is dominated by flavor violating couplings: minimal flavor violating models with a large bottom Yukawa, models with horizontal symmetries, and DM in nontrivial flavor group representations. Discovery at the 7 TeV LHC with a few ${\mathrm{fb}}^{-1}$ may already be possible.

Figure 1

Flavor violating DM production at collider in the EFT description (left) and for two on-shell models, (a) with a SM gauge singlet $S$, and (b) with a color triplet $\tilde{t}$ as a mediator.

Figure 2

The ratio $\sigma (t+2\chi )/\sigma (j+2\chi )$ as a function of DM mass at Tevatron with ${\mathrm{E̸}}_T>80\mathrm{GeV}$ (black solid, blue dashed) and at 7 TeV LHC with ${\mathrm{E̸}}_T>120\mathrm{GeV}$ (red dotted, green dot-dashed) for MFV (4a, 4b) and horizontal (7) couplings denoted by (MFV) and (Horiz.), respectively, in the EFT limit.

Figure 3

The $m_S$ dependence of $\mathrm{Br}(t\to j+\chi \chi )$ (red dotted) and of $\sigma (t+2\chi )$ at 7 TeV LHC in model (9) for $g_L^u=1$ (blue dashed) and $g_L^c=1$ (black solid), keeping all other $g_i=0$ in each case.

Figure 4

Cross sections for single and pair produced ${\tilde{t}}_1$ (9) taking $g_L^{c(u)}={\lambda }^{1(3)}$ resulting in $t+{\mathrm{E̸}}_T$ and $t\overline{t}+{\mathrm{E̸}}_D$ signal at 7 TeV and 14 TeV LHC.