Speaker
Description
New physics at the LHC may be hiding in non-standard final state configurations, particularly in cases where stringent particle identification could obscure the signal. Here we present a search for resonances in the three-photon final state where two photons are highly merged. We target the case where a heavy vector-like particle decays to a photon and a new spin-0 particle $\phi$, where $\phi$ is light and decays to two photons, resulting in a merged diphoton signature. To classify and obtain the relevant kinematic properties of these merged photons, we use a convolutional neural network that takes individual crystal deposits in the CMS electromagnetic calorimeter as input. This method performs remarkably well for these highly merged decays where standard particle identification fails.
