  The search for new physics beyond the Standard Model has interesting
possibilities at low energies. For example, the recent 6.8$\sigma$ anomaly
reported in the invariant mass of $e^+e^-$ pairs from $^8\text{Be}$ nuclear
transitions and the discrepancy between predicted and measured values of muon
g-2 give strong motivations for a protophobic fifth-force model. At low
energies, the electromagnetic interaction is well understood and produces
straightforward final states, making it an excellent probe of such models.
However, to achieve the required precision, an experiment must address the
substantially higher rate of electromagnetic backgrounds. In this paper, we
present the results of simulation studies of a trigger system, motivated by the
DarkLight experiment, using helical-shape scintillating fibers in a solenoidal
magnetic field to veto electron-proton elastic scattering and the associated
radiative processes. We also assess the performance of a tracking detector for
lepton final states using scintillating fibers in the same setup.
