New vector portal light dark matter searches at Fermilab's Short Baseline Near Detector (SBND)

SBND is one of three liquid argon neutrino detectors sitting along the booster neutrino beam (BNB) of Fermilab's Short-Baseline Neutrino (SBN) program. It is a 112 ton Liquid Argon Time Projection Chamber (LArTPC) situated 110 meters from the beam and has just started taking data that will provide unprecedented statistics on neutrino-argon cross sections and neutrino flavor oscillations. In addition, SBND's proximity to the BNB target provides sensitivity to probe a plethora of Beyond Standard Model (BSM) scenarios, such as several classes of dark matter (DM) models. One model of interest to SBND is vector portal light dark matter, which involves a hypothetical force-carrying gauge boson in the dark sector, the dark photon, coupling to the standard model (SM) photon. This coupling, combined with the high performance of LArTPC technology in reconstructing photon, electron, and nucleon signals, make SBND an ideal experiment to probe newly-accessible parameter space of this DM model. In this talk, we will first introduce the SBN program, SBND, and LArTPC detection technology in particle physics. Then, we will look at phenomenological aspects of this light DM model useful for detection. Lastly, we will present new expected exclusion limits to this model's parameter space for certain proposed production and signal channels, namely π0 decay in flight (π0→γ+χ+χ†) and elastic neutral current (NC)-like nucleon scattering (N+χ→N+χ).