Searching for the dark photon at the Future Circular Lepton Collider

Abstract

In the context of future electroweak precision measurements at the Future Circular Lepton Collider (FCC-ee), we consider recent proposals aimed at finding signatures of physics beyond the Standard Model. In particular, we focus on recent novel suggestions for very precise direct measurements of ${\alpha }_{\mathrm{em}}\left(M_Z^2\right)$. It is shown that at a level of precision of order ${10}^{-5}$, the effects of a dark photon may be very significant.