Search for pair produced long-lived neutral particles decaying in the ATLAS hadronic calorimeter in $pp$ collisions at $\sqrt{s}= 8~\rm{TeV}$

The ATLAS detector at the Large Hadron Collider at CERN is used to search for the decay of a light scalar boson to a pair of long-lived particles, neutral under the Standard Model, in $20.3~\rm{fb}^{-1}$ of data collected in proton-proton collisions at $\sqrt{s} = 8~\rm{TeV}$. A benchmark model with a light scalar boson that couples to mass in the same manner as the Higgs boson is considered. This search is sensitive to long-lived particles that decay to jets at the outer edge of the ATLAS electromagnetic calorimeter or inside the hadronic calorimeter. No significant excess of events is observed. Limits are reported on the product of the scalar boson production cross-section times branching ratio into long-lived neutral particles as a function of the proper lifetime of the particles. Limits are reported for boson masses between $100$ and $140~\rm{GeV}$, and a long-lived neutral particle mass between $10$ and $40~\rm{GeV}$.