Search for long-lived neutral particles decaying in the hadronic calorimeter of ATLAS at $\sqrt{s} = 13~\mathrm{TeV}$ in $3.2~\mathrm{fb^{-1}}$ of data

Long-lived neutral particles can be featured in many proposed extensions to the Standard Model and may provide a novel path to the discovery of heavy Higgs-like scalars at the Large Hadron Collider. This note describes a search for neutral, long-lived particles produced from heavy-scalar decays in proton-proton collisions, at a center-of-mass energy of $13~\mathrm{TeV}$, which have a displaced decay to fermions. This analysis uses $3.2~\mathrm{fb^{-1}}$ of data recorded with the ATLAS detector during 2015. No excess in data is observed. $95\%$ CL upper limits on cross-section times branching ratio are reported for heavy bosons with masses between $\mathrm{m_{\Phi}} = 400~\mathrm{GeV}$ and $1~\mathrm{TeV}$ that decay to pairs of scalars with masses between $\mathrm{m_{s} = 50~\mathrm{GeV}}$ and $400~\mathrm{GeV}$.