The stau-neutralino co-annihilation region and the collider experiments

We examine the cold dark matter relic density allowed region of SUGRA parameter space in collider experiments. All current experimental bounds on the mSUGRA parameter space are imposed. We study the SUSY signals that would be observable for the dominant stau-neutralino co-annihilation region in a 500/800 GeV linear collider. The detection of the signals in this region requires a complicated analysis due to the fact that the dark matter co-annihilation constraint requires that the τ˜1 and χ˜10 mass difference be ⩽15 GeV. The signal contains soft taus. We analyze the SM background and develop necessary cuts to extract the signal. We then utilize these event acceptances to probe the SUGRA models which explain the the recent Belle and BABAR measurements of the B → ϕK CP violating parameters and branching ratios.