Møller electrons and radiative tridents for determining the HPS detector resolution

The Heavy Photon Search (HPS) experiment at Jefferson Lab is searching for a new U (1) vector boson, the "heavy" photon or A', that could mediate dark-sector interactions in the mass range of 20 − 500 M eV /c2 through their decay to e−e+ pairs via kinetic mixing with the ordinary photon. The decay can be observed as a narrow resonance above the QED invariant mass background. For small couplings, the heavy photons can travel a small distance before decaying, providing a second method for detection in the form of a displaced vertex away from the target. Both of these detection methods rely on a good understanding of the mass resolution of the HPS detector. The mass resolution is determined through Møller electron scattering and radiative three-prong tridents. Characterizing the e−e+ pair within the radiative trident is of particular significance, as it is the detectable decay product of the A'. This talk will discuss the ways in which Møller-scattering and three-prong radiative tridents are used to extract mass and energy resolutions for the HPS detector.