Speaker
Description
A recast is developed for a search for non-pointing, delayed photons originating from the decay of a neutral long-lived particle (LLP) produced via an effective coupling in Higgs decays within the ATLAS detector. The LLP decays in the inner detector, producing an invisible particle and the signal photon. The analysis includes a refined calculation of non-pointing parameters, taking into account the energy deposition of the photons in the strip and middle layers of the electromagnetic calorimeter. We modify the detector simulation by Delphes such that this information is passed on within its output, and adapt the particle isolation criteria. Efficiencies and resolutions based on published ATLAS results are incorporated to ensure accurate detector modeling. The study sets bounds on the branching ratio of Higgs decays into scalars, where each scalar subsequently decays into a displaced photon and a dark photon, the latter being a dark matter candidate. A range of scalar masses and Higgs-scalar couplings is explored.