Beyond the Higgs boson at the Tevatron: Detecting gluinos from Yukawa-unified SUSY

Simple SUSY GUT models based on the gauge group SO(10) require t-b-τ Yukawa coupling unification, in addition to gauge coupling and matter unification. The Yukawa coupling unification places strong constraints on the expected superparticle mass spectrum, with scalar masses ∼10 TeV while gluino masses are much lighter: in the 300-500 GeV range. The very heavy squarks suppress negative interference in the qq¯→g˜g˜ cross section, leading to a large enhancement in production rates. The gluinos decay almost always via three-body modes into a pair of b-quarks, so we expect at least four b-jets per signal event. We investigate the capability of Fermilab Tevatron collider experiments to detect gluino pair production in Yukawa-unified SUSY. By requiring events with large missing ET and ⩾2 or 3 tagged b-jets, we find a 5σ reach in excess of mg˜∼400 GeV for 5 fb−1 of data. This range in mg˜ is much further than the conventional Tevatron SUSY reach, and should cut a significant swath through the most favored region of parameter space for Yukawa-unified SUSY models.