Prospects for measurements of the Higgs boson couplings at TLEP

The discovery by the ATLAS and CMS experiments of a new boson with mass around 125 GeV and with measured properties compatible with those of a Standard-Model Higgs boson, coupled with the absence of discoveries of phenomena beyond the Standard Model up to scales of sev- eral hundred GeV, has triggered interest in ideas for future Higgs factories. A new circular e + e collider hosted in a 80 to 100 km tunnel, TLEP, is among the most attractive solutions proposed so far. It has a clean experimental environment, produces high luminosity for Higgs boson stud- ies, accommodates multiple detectors, and can reach energies up to the t ̄ t threshold and beyond. Moreover, being the natural precursor of the VHE-LHC, a 100 TeV hadron machine in the same tunnel, it builds up a long-term vision for particle physics. This paper describes the expected precision on the measurement of the Higgs boson couplings with a TLEP run between 250 and 350 GeV.