Neutralino dark matter and other LHC predictions from quasi Yukawa unification

We explore the dark matter and LHC implications of t - b - tau quasi Yukawa unification in the framework of supersymmetric models based on the gauge symmetry G = SU(4)(c) x SU(2)(L) x SU(2)(R). The deviation from exact Yukawa unification is quantified by a dimensionless parameter C(vertical bar C vertical bar less than or similar to 0.2), such that the Yukawa couplings at M-GUT are related by yt : yb : y tau = vertical bar 1 + C vertical bar : vertical bar 1 -C vertical bar : vertical bar 1 + 3C vertical bar. In contrast to earlier studies which focused on universal gaugino masses, we consider non-universal gaugino masses at M-GUT that are compatible with the gauge symmetry G. Our results reveal a variety of neutralino dark matter scenarios consistent with the observations. These include stau and chargino coannihilation scenarios, the A-resonance scenario, as well as Higgsino dark matter solutions which are more readily probed by direct detection searches. The gluino mass is found to be less than or similar to 4 TeV, the stop mass is greater than or similar to 2 TeV, while the first two family squarks and sleptons are of order 4-5 TeV and 3 TeV respectively. (C) 2015 The Authors. Published by Elsevier B.V.