Uncertainty in Electroweak Symmetry Breaking in Models With High Scale Supersymmetry Breaking and its Impact on Interpretations of Searches For Supersymmetric Particles

摘要

Some regions of parameter space of the minimal supersymmetric standard model(MSSM) with high scale supersymmetry breaking have extreme sensitivity ofelectroweak symmetry breaking (EWSB) to the top quark mass throughrenormalisation group evolution effects. This leads to uncertainties in thepredictions which need to be taken into account in the interpretation ofsearches for supersymmetric particles in these regions. As an example, weprovide estimates of the current uncertainties on the position in parameterspace of the region which does not break electroweak symmetry in theconstrained MSSM (CMSSM). The position of the boundary of EWSB can vary by upto 2 TeV in m_0 due to the uncertainties coming from the current measurementerrors on the top quark mass and from higher order corrections. In thisdangerous region, for fixed CMSSM parameters the neutralino lightestsupersymmetric particle mass has an associated large uncertainty of order 100%.These uncertainties therefore have a profound effect on the interpretation ofLHC supersymmetric particle searches in terms of the CMSSM. We also show how toameliorate poor convergence of the iterative numerical algorithm thatcalculates the MSSM spectrum near the boundary of EWSB.