Speaker
Description
A search for the production of long-lived particles in proton-proton collisions at a center-of-mass energy of 13 TeV at the CERN LHC is presented. The search is based on data collected by the CMS experiment in 2016–2018, corresponding to a total in- tegrated luminosity of 137 fb−1. This search is designed to be sensitive to long-lived particles with mean proper decay lengths between 0.1 and 1000 mm, whose decay products produce a final state with at least one displaced vertex and missing trans- verse momentum. A machine learning algorithm, which improves the background rejection power by more than an order of magnitude, is applied to improve the sen- sitivity. The observation is consistent with the standard model background predic- tion, and the results are used to constrain split supersymmetry (SUSY) and gauge- mediated SUSY breaking models with different gluino mean proper decay lengths and masses. This search is the first CMS search that shows sensitivity to hadronically decaying long-lived particles from signals with mass differences between the gluino and neutralino below 100 GeV. It sets the most stringent limits to date for split-SUSY models and gauge-mediated SUSY breaking models with gluino proper decay length less than 6 mm.
