Update of the Higgs Self-coupling Projections from Di-Higgs Production in Detailed Simulation of the ILD Concept

Abstract

This contribution summarizes the update of the projections for the determination of the tri-linear Higgs self-coupling from di-Higgs production at future $e^{+}{e}^{-}$ colliders. In particular, we will present an update of the analysis of $ZHH$ production at 500 GeV in detailed simulations of the ILD concept, covering the $HH\to b\bar{b}b\bar{b}$ and $Z\to q\bar{q}/e^{+}{e}^{-}/{\mu }^{+}{\mu }^{-}/\nu \bar{\nu }$ channels. Based on the experience of previous analyses, we will extrapolate these to contain some of the remaining decay modes, e.g. $HH\to b\bar{b}W{W}^{\ast }$ or $Z\to {\tau }^{+}{\tau }^{-}$, as well as the contribution from the $WW$ fusion production mode. We will study the dependency of the results on the centre-of-mass energy (in particular discussing 550 GeV and 1 TeV) as well as on the value of the trilinear coupling realised in nature.