Non-zero trilinear parameter in the mSUGRA model-dark matter and collider signals at Tevatron and LHC(Summer Institute 2007)

Abstract

Regions of the parameter space in the minimal super-gravity(mSUGRA) model with small m_0 and small m_<1/2> consistent with the WMAP data on dark matter relic density and the bound on the mass of the lightest Higgs scalar from LEP2(m_h > 114.4 GeV) open up if the rather adhoc assumption A_0=0 is relaxed. For moderate to large negative values of A_0 in several processes including lightest supersymmetric particle(LSP) pair annihilation, LSP-lighter tau slepton (τ^^〜_1) co-annihilation and LSP lighter top squark (t^^〜_1) co-annihilation contribute to the observed dark matter relic density. Such a t^〜_1 can be observed at the current experiments at the Tevatron. At the LHC a very distinctive semi-inclusive signature τ^±+X_τ(anything without a tau lepton) with a characteristic size much larger than e^±+X_e or μ^±+X_μ events can be observed during the early runs.