Speaker
Description
Many supersymmetry models of general gauge mediation or gauge-mediated supersymmetry breaking predict gravitinos as the lightest supersymmetric particle with higgsino-dominated neutralinos as the next-to-lightest supersymmetric particle. This poster presents a search for pair-produced higgsinos each decaying to a Higgs boson and gravitino in the $b\bar{b}$ Higgs boson decay channel. The search uses the full Run 2 dataset of the ATLAS detector with an integrated luminosity of 126 fb$^{-1}$ in $pp$ collisions at $\sqrt{s}=$ 13 TeV. Higgsinos with mass less than 300 GeV are targeted in this analysis, which will be combined with an analysis targeting higgsinos with mass greater than 300 GeV. The backgrounds are dominated by difficult-to-model QCD multijet events and are estimated using a novel data-driven approach utilizing a reweighting boosted decision tree. The expected limits show strong sensitivity to the target scenarios.
