Can a new electron beam find hidden particles between atoms and nuclei?

MAGIX, a precision electron-scattering experiment at MESA, will fire 55 and 105 MeV beams at tantalum to create exotic particles via pair production. By carefully selecting which collision products they measure, the team shows they can detect scalar, vector, and axial mediators down to electron coupling strengths of 10−4—competitive with particle physics' best dark sector searches. This opens a new window on light BSM physics that higher-energy colliders miss.