1AAD 2025J search for non-resonant ${{\mathit H}}{{\mathit H}}{{\mathit H}}$ production using ${{\mathit H}}$ ${{\mathit H}}$ ${{\mathit H}}$ $\rightarrow$ ${{\mathit b}}{{\overline{\mathit b}}}{{\mathit b}}{{\overline{\mathit b}}}{{\mathit b}}{{\overline{\mathit b}}}$ with data of 126 fb${}^{-1}$ at $\mathit E_{{\mathrm {cm}}}$ = 13 TeV. Two-dimensional likelihood scan of (${{\mathit \kappa}_{{{3}}}}$ (=${{\mathit \kappa}_{{{\lambda}}}}$), ${{\mathit \kappa}_{{{4}}}}$) is shown in their Fig. 9. The quoted values are obtained by assuming ${{\mathit \kappa}_{{{3}}}}$ = 1. Note that the quoted values are calculated using the kappa framework, which outside the unitarity bounds requires additional modification to preserve unitarity for their results.
References:
AAD
2025J
PR D111 032006
A search for triple Higgs boson production in the $6b$ final state using $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
