Likelihood analysis of supersymmetric SU(5) GUTs

We perform a likelihood analysis of the constraints from accelerator experiments and astrophysical observations on supersymmetric (SUSY) models with SU(5) boundary conditions on soft SUSY-breaking parameters at the GUT scale. The parameter space of the models studied has seven parameters: a universal gaugino mass m_1/2, distinct masses for the scalar partners of matter fermions in five- and ten-dimensional representations of SU(5), m₅ and m₁₀, and for the 5 and anti 5 Higgs representations m_Hu and m_Hd, a universal trilinear soft SUSY-breaking parameter A₀, and the ratio of Higgs vevs tan β. In addition to previous constraints from direct sparticle searches, low-energy and flavour observables, we incorporate constraints based on preliminary results from 13 TeV LHC searches for jets + E_T events and long-lived particles, as well as the latest PandaX-II and LUX searches for direct Dark Matter detection. In addition to previously identified mechanisms for bringing the supersymmetric relic density into the range allowed by cosmology, we identify a novel u_R/c_R - χ⁰₁ coannihilation mechanism that appears in the supersymmetric SU(5) GUT model and discuss the role of ν_τ coannihilation. We find complementarity between the prospects for direct Dark Matter detection and SUSY searches at the LHC. (orig.)