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 lambda. I present a detailed analysis of the e(+)e(-)-> ZHH and e(+)e(-)->nu nu HH 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 nonresonant Feynman diagrams play, and the theoretical uncertainties of signal and background cross sections. I also derive quantitative sensitivity limits for lambda. I find that an e(+)e(-) collider with s=0.5 TeV can place meaningful bounds on lambda 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), lambda 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 m(H)=120-180 GeV.