Analysis strategies for in-time pile-up events in LDMX

The Light Dark Matter Experiment (LDMX) is a fixed target, missing momentum experiment aimed at finding thermal relic dark matter in the sub-GeV mass range. In this approach, incoming electrons scattering in a thin tungsten target can produce dark matter via "dark bremsstrahlung," giving rise to significant missing momentum and energy in downstream detectors. To identify these rare signal events, LDMX must individually tag incoming beam-energy electrons, unambiguously associate them with low energy recoils of the incoming electron, and establish the absence of any additional final-state particles. While LDMX intends to operate with an average of one electron on target per event, as expected in the low-current, high-repetition rate environment provided by SLAC's 8 GeV LCLS-II beam, extending analysis capability to include events with multiple incident beam electrons can improve signal acceptance and accelerate accumulation of events to reach the intended 10¹⁶ electrons on target. This talk will present preliminary results towards a multi-electron analysis strategy in LDMX, including studies of trigger strategy/performance, tracking performance, clustering in the electromagnetic calorimeter, and track-cluster association.