Recasting the ATLAS stop–chargino analysis with CheckMATE

Abstract

We present a CheckMATE recast of the ATLAS 13 TeV high–b–jet search. The implementation is validated by comparing the published stop–chargino cutflow to within the ~10% accuracy required for certified analyses and by replicating the published exclusion contour in the (m_t̃, m_χ̃1±) plane. Relative to the existing CheckMATE analyses, the new analysis tightens the stop limit to m_t̃ = 680–750 GeV for m_χ̃1± < 900GeV. Applying the same selection to gluino pair production g̃ → bb̅ χ̃₁⁰ excludes m_g̃ = 400–900GeV for moderate neutralino masses, demonstrating sensitivity beyond the original RPV topology. Residual gaps at very light χ̃₁⁰ or m_g̃  ≳ 1 TeV are traced to the analysis's low-E_T^miss design, suggesting that a MET-optimised variant could extend the reach. The work provides a robust baseline for future reinterpretations across a wider class of BSM scenarios.