Speaker
Description
Evidence for Dark Matter particles arising from direct searches has proven to be extremely elusive. An alternative approach to probing the dark sector is to search for new force carriers which can interact with Standard Model particles. A theoretically well-motivated model has proposed the presence of a new U(1) gauge boson, the heavy photon A', which might be a mediator between light thermal Dark Matter and Standard Model particles. The Heavy Photon Search Experiment (HPS) at the Thomas Jefferson National Accelerator Facility, JLab, has been designed to search for such a heavy photon by exploiting its kinetic mixing with the Standard Model photon. Heavy photons could be created via electro-production reactions of electrons on a tungsten target with subsequent decays to electron-positron pairs. Experimental signatures for detection in HPS are either a resonance peak in the electron-positron invariant mass distribution or displaced decay vertices with a particular invariant mass, depending on the heavy photon mass and the strength of its coupling to electrons. HPS recently submitted the results of its analysis of data taken during an engineering run in 2016 for publication. Data taken during physics runs in 2019 and 2021 are currently being analyzed and offer the possibility of probing regions in the mass-coupling space which are favored by models of thermal dark matter production in the early universe. In this presentation, we will describe the design and performance of the HPS detector, the results of our 2016 data analysis, and the status of and prospects for the analysis of our two larger datasets.
