We perform a global effective-field-theory analysis to assess the precision on the determination of the Higgs trilinear self-coupling at future lepton colliders. Two main scenarios are considered, depending on whether the center-of-mass energy of the colliders is sufficient or not to access Higgs pair production processes. Low-energy machines allow for ~40% precision on the extraction of the Higgs trilinear coupling through the exploitation of next-to-leading-order effects in single Higgs measurements, provided that runs at both 240/250 GeV and 350 GeV are available with luminosities in the few attobarns range. A global fit, including possible deviations in other SM couplings, is essential in this case to obtain a robust determination of the Higgs self-coupling. High-energy machines can easily achieve a ~20% precision through Higgs pair production processes. In this case, the impact of additional coupling modifications is milder, although not completely negligible.
@article{arxiv.1711.03978,
title = {A global view on the Higgs self-coupling at lepton colliders},
author = {Stefano Di Vita and Gauthier Durieux and Christophe Grojean and Jiayin Gu and Zhen Liu and Giuliano Panico and Marc Riembau and Thibaud Vantalon},
journal= {arXiv preprint arXiv:1711.03978},
year = {2018}
}