Likelihood analysis of the minimal AMSB model

We perform a likelihood analysis of the minimal anomaly-mediated supersymmetry-breaking (mAMSB) model using constraints from cosmology and accelerator experiments. We find that either a wino-like or a Higgsino-like neutralino LSP, χ̃^0_1 , may provide the cold dark matter (DM), both with similar likelihoods. The upper limit on the DM density from Planck and other experiments enforces m_χ̃^0_1≲ 3 TeV after the inclusion of Sommerfeld enhancement in its annihilations. If most of the cold DM density is provided by the χ̃^0_1 , the measured value of the Higgs mass favours a limited range of tanβ∼ 5 (and also for tanβ∼ 45 if μ > 0 ) but the scalar mass m_0 is poorly constrained. In the wino-LSP case, m_3/2 is constrained to about 900 TeV and m_χ̃^0_1 to 2.9± 0.1 TeV , whereas in the Higgsino-LSP case m_3/2 has just a lower limit ≳ 650 TeV ( ≳ 480 TeV ) and m_χ̃^0_1 is constrained to 1.12 (1.13) ± 0.02 TeV in the μ >0 ( μ <0 ) scenario. In neither case can the anomalous magnetic moment of the muon, (g-2)_μ , be improved significantly relative to its Standard Model (SM) value, nor do flavour measurements constrain the model significantly, and there are poor prospects for discovering supersymmetric particles at the LHC, though there are some prospects for direct DM detection. On the other hand, if the χ̃^0_1 contributes only a fraction of the cold DM density, future LHC -based searches for gluinos, squarks and heavier chargino and neutralino states as well as disappearing track searches in the wino-like LSP region will be relevant, and interference effects enable BR(B_s, d→μ ^+μ ^-) to agree with the data better than in the SM in the case of wino-like DM with μ > 0 .