Particle Physics Seminar: Search for long-lived neutral particles decaying into displaced lepton-jets in proton–proton collisions at √s=13 TeV with the ATLAS detector

Abstract: 

I will talk about the results of a search for long-lived neutral particles decaying into collimated jets of light leptons and mesons, so-called “lepton-jets”, using a sample of 3.4 fb-1 of proton-proton collisions data at a centre-of-mass energy of √s=13 TeV collected during 2015 with the ATLAS detector at the LHC. No deviations from Standard Model expectations are observed. Limits on models predicting Higgs boson decays to neutral long-lived particles (dark photons γd), which in turn produce lepton-jets, are derived as a function of the particle proper decay length, cτ. This search has greater sensitivity compared with a similar search previously performed during Run 1 of the LHC, due to enhancements I have introduced in the trigger and reconstruction of highly-collimated muons.

Seminar Organizer: Prof. Nissan Itzhaki