Lower Limit on Dark Matter Production at the CERN Large Hadron Collider

We evaluate the prospects for finding evidence of dark matter production at the CERN Large Hadron Collider. We consider weakly interacting massive particles (WIMPs) and superWIMPs and characterize their properties through model-independent parametrizations. The observed relic density then implies lower bounds on dark matter production rates as functions of a few parameters. For WIMPs, the resulting signal is indistinguishable from background. For superWIMPs, however, this analysis implies significant production of metastable charged particles. For natural parameters, these rates may far exceed Drell-Yan cross sections and yield spectacular signals.

Figure 1

Minimum Tevatron and LHC cross sections derived from cosmology, along with the Drell-Yan cross section, for $L^{+}{L}^{-}$ production in the superWIMP scenario as functions of $m_L$. Each event has two highly ionizing tracks with velocity $\beta <0.7$ and pseudorapidity $|\eta |<2.5$. We assume $S_L=0$, $m_{\mathrm{SWIMP}}/m_L=0.6$, and ${\kappa }_{q\overline{q}}=0.2$, for $q=d,u,s,c,b$.

Figure 2

Discovery limits for dark matter events in the superWIMP scenario at the Tevatron with $L=30{\mathrm{fb}}^{-1}$, LHC with $L=1{\mathrm{ab}}^{-1}$, and ILC with $L=1{\mathrm{ab}}^{-1}$. We require 10 events with two doubly minimum-ionizing tracks for discovery. For the ILC, the beam energy is assumed to be $\sqrt{s}\approx 2.8m_L$, so that $L$ particles are produced with $\beta =0.7$. We assume $S_L=0$, $P$-wave annihilation, and $m_{\mathrm{SWIMP}}/m_L=0.6$. The reach in $\kappa$ scales linearly with $(2S_L+1{)}^{-2}$ and, to an excellent approximation, $(m_{\mathrm{SWIMP}}/m_L{)}^{-1}$.