Searching for the Migdal Effect

The Migdal effect is a rare atomic process in which a sudden kick to the atomic nucleus can, with a small probability, lead to the emission of an electron or other forms of radiation. Several large-scale dark matter (DM) experiments have recently invoked this effect to rule out low-mass parameter space, but it has never been experimentally observed under the conditions applicable for DM searches, i.e., in nuclear recoils from electrically neutral projectiles. Thus, a current effort by the MIGDAL collaboration is underway to directly observe and characterize this effect in gases of interest for DM. This will be accomplished using a low-pressure optical time projection chamber equipped with a fast CMOS ORCA-Fusion camera recording high-resolution track images generated by a stack of two glass Gas Electron Multipliers (GEMs) and an Indium Tin Oxide (ITO) anode plane segmented into 120 readout strips enabling full 3D reconstruction of Migdal event topologies. In this talk, I will describe the MIGDAL experiment, some of its challenges, and the methods we are developing to mitigate these for an accurate measurement.