Topical seminar: Search for heavy charged long-lived particles in ATLAS using massive event picking

by Dario Barberis (University of California, Berkeley (USA) and Università e INFN Genova)

Wednesday 28 May 2025, 10:00 → 12:00 Europe/Madrid

1001-Primera-1-1-1 - Paterna. Seminario (Universe)

Several SUSY-inspired theoretical models predict the production of heavy long-lived particles through R-parity violating interactions at LHC. If these particles are charged and have lifetimes above 1 ns, they can be detected in the ATLAS detector through the ionisation left in the silicon pixel detectors, and their mass can be measured using the Bethe-Bloch relation. Several searches were conducted in the last few years using LHC Run 2 data; analysis of newer Run 3 data is in progress. After many years in operation, radiation damage is decreasing substantially the amount of collected charge and has to be taken into account for the new analysis; for this reason a new calibration procedure has been developed and implemented. In order to avoid a global reprocessing of all existing data, massive event picking is used for this analysis. This talk will describe the results already achieved and the new procedures that will enhance the mass resolution, and hence the reach, of the current analysis.