Speaker
Description
The Future Circular Collider with electron-positron beams (FCC-ee) should provide improvements of the electroweak precision measurement concerning Z, W, H and their masses by a large factor over the present status. The unparalleled experimental precision would open, via Electroweak loop corrections, a broad discovery potential for new, at least weakly interacting particles up to high energy scales. The Z boson mass and width, as well as the Z → bb partial width, and the forward-backward asymmetries for leptons and quarks can be measured with high precision with the run at the Z pole, where the instantaneous luminosity is expected to be five to six orders of magnitude larger than LEP. As a result, a precise determination of the effective weak mixing angle, as well as of the running electromagnetic coupling $\alpha_{QED}(m_Z)$ can be extracted directly from the data. Considerable improvements of the strong coupling constant determination down to a precision of $\Delta \alpha_s(mZ)≃ \pm 0.0001$ will be possible with the measurements of the hadronic widths of the Z and W bosons.
