Hannah Herde: From dark current to dark matter: The Light Dark Matter eXperiment

Tuesday 10 Feb 2026, 13:15 → 14:00 Europe/Stockholm

FA32 (AlbaNova Main Building)

The world associates SLAC National Accelerator Laboratory’s LCLS-II-HE with photon science at 8 GeV, pumping high-intensity free-electron laser bunches to users. Yet, between those bunches, the radio-frequency photoelectron gun produces 200 almost-empty buckets. This low-charge “dark current” is perfect for the Light Dark Matter eXperiment (LDMX), a fixed-target experiment designed to provide a decisive test of sub-GeV thermal relic dark matter scenarios and, more broadly, explore the well-motivated parameter space for light new physics. A new beamline, Linac to End Station A (LESA), will form the LCLS-II-HE dark current into a low-current, high-repetition-rate electron beam. The LESA beam will strike LDMX's thin target, producing dark matter particles which carry away most of the beam energy. The electron loses most of its energy while receiving a transverse kick. LDMX’s particle tracking system either side of the target determines the momentum change, complemented with energy measurements in the forward electromagnetic and hadronic calorimeters. This talk reviews the present status of this proposed experiment, including projected sensitivities relative to other experiments (detailed in our recent design report) and our first joint LESA-LDMX operations using our latest prototypes.

About the speaker:  Dr. Hannah Herde is an associate senior lecturer at Lund University in experimental particle physics. She is a member of the ATLAS Collaboration at CERN and the LDMX Collaboration at SLAC National Accelerator Laboratory. She is deeply curious about the natures of the Higgs sector and dark matter. She primarily works on these questions through designing, assembling, and calibrating better detectors. 

In the OKC:  Feb 9th-10th, in the C5 (SU ELPA) corridor

Photo credit:  Kennet Ruona