Vertexing algorithm R&D for the search of displaced vertices with jet final states in CMS

We report on a search for displaced vertices that is model-independent, and is sensitive to long-lived particles (LLPs) under a low-background environment. This search for a pair of long-lived particles in proton-proton collisions at the LHC at √s = 13 TeV, using the CMS data collected from 2015 through 2018, corresponding to a total integrated luminosity of 140 fb^-1, was analyzed and targeted to long-lived particles with mean proper decay lengths between 0.1 and 100 mm. Predicted backgrounds are low, and no significant excess of events with two displaced vertices was found. In the future iterations of the search, our vertexing algorithm will better reconstruct signals by resolving cases where a single LLP is reconstructed as multiple displaced vertices, and target spurious background events where two well-separated vertices are associated to the same jet in order to extend the signal sensitivity by relaxing track and vertex quality criteria.