Measuring the Higgs Boson Self-coupling at High Energy e+e− Colliders

Standard Model Higgs pair production at e+e− colliders has the capability to determine the Higgs boson self-coupling λ. I present a detailed analysis of the e+e− → ZHH and e+e− → νν̄HH signal channels, and the relevant background processes, for future e+e− linear colliders with center of mass energies of √ s = 0.5 TeV, 1 TeV, and 3 TeV. Special attention is given to the role non-resonant Feynman diagrams play, and the theoretical uncertainties of signal and background cross sections. I also derive quantitative sensitivity limits for λ. I find that an e+e− collider with √ s = 0.5 TeV can place meaningful bounds on λ only if the Higgs boson mass is relatively close to its current lower limit. At an e+e− collider with √ s = 1 TeV (3 TeV), λ can be determined with a precision of 20 − 80% (10 − 20%) for integrated luminosities in the few ab−1 range and Higgs boson masses in the range mH = 120− 180 GeV. [email protected]