Complex decay chains of top and bottom squarks

Current searches for the top squark mostly focus on the decay channels of (formula presented), leading to tt/bbWW + [InlineMediaObject not available: see fulltext.] final states for top squark pair production at the LHC. In supersymmetric scenarios with light gauginos other than the neutralino lightest supersymmetric particle (LSP), different decay modes of the top squark could be dominant, which significantly weaken the current top squark search limits at the LHC. Additionally, new decay modes offer alternative discovery channels for top squark searches. In this paper, we study the top squark and bottom squark decay in the Bino-like LSP case with light Wino or Higgsino next-to-LSPs (NLSPs), and identify cases in which additional decay modes become dominant. We also perform a collider analysis for top squark pair production with mixed top squark decay final states of (formula presented), leading to the bbbbjjℓ + [InlineMediaObject not available: see fulltext.] collider signature. The branching fraction for such decay varies between 25% and 50% for a top squark mass larger than 500 GeV with M₂= M₁+ 150 GeV. At the 14 TeV LHC with 300 fb⁻¹ integrated luminosity, the top squark can be excluded up to about 1040 GeV at the 95% C.L., or be discovered up to 940 GeV at 5σ significance.