Speaker
Description
The Light Dark Matter eXperiment (LDMX) proposes a high-statistics search for low-
mass dark matter at a new experimental facility, Dark Sector Experiments at LCLS-II
(DASEL), at SLAC. LDMX employs the missing momentum technique, where electrons
scattering in a thin target can produce dark matter via “dark bremsstrahlung” that are
not observed in the detector. To identify these rare signal events, LDMX individually tags
incoming beam-energy electrons, unambiguously associates them with low energy, moderate
transverse-momentum recoils of the incoming electron, and establishes the absence of any ad-
ditional forward-recoiling charged particles or neutral hadrons. LDMX will employ low mass
tracking to tag incoming beam-energy electrons with high purity and cleanly reconstruct
recoils. A high-speed, granular calorimeter with MIP sensitivity is used to reject the high
rate of bremsstrahlung background at trigger level while working in tandem with a hadronic
calorimeter to veto rare photo nuclear reactions. Ultimately, LDMX aims to probe thermal
dark matter over most of the viable sub-GeV mass range to a decisive level of sensitivity.
This talk will summarize the current status of the LDMX design and performance studies
and progress in developing the DASEL beamline.
