Electroweak and CP violation physics at a Linear Collider Z-factory

Abstract

A future linear collider such as TESLA may be able to run on the Z0 resonance with very high luminosity and polarised electron and positron beams. The possibilities of measuring electroweak quantities with high precision are investigated. Huge improvements with respect to the present precision can be expected, especially for the asymmetries ALR and \({\cal A}_{\rm b}\) where beam polarisation can be exploited. The very large sample of \({\rm Z}^0 \to b{\bar b}\) events also allows studies of various CP-violating b decays. The precision achievable on the CKM unitarity triangle angles is comparable to experiments at b factories and future hadron colliders.