Potential for the discovery of the protophobic boson at the STCF

A bstract We study the morphology of the main drift chamber (MDC) to be built around the collision point of the proposed Super tau-charm facility (STCF), to check its suitability for discovering the 17 MeV protophobic boson (X17 boson), hypothesised as a solution to the persistent ATOMKI nuclear-transition anomalies. Using the TrackEff framework, we perform detector-level simulations of the STCF MDC, and evaluate displaced-vertex sensitivities towards the protophobic boson, across the relevant mass-coupling parameter space. We study benchmark scenarios with visible and dark decay channels to perform likelihood-based significance estimates in order to determine the 5 σ discovery reach for the protophobic boson. We find that STCF can potentially discover the protophobic boson while tolerating ~ 10 4 background events for specific regions of the parameter space. Our analysis establishes the first feasibility study of displaced light-boson searches at the STCF, motivating a full Geant-4 simulation.