Search for Nonresonant Pair Production of Highly Energetic Higgs Bosons Decaying to Bottom Quarks

A search for nonresonant Higgs boson ( H ) pair production via gluon and vector boson ( V ) fusion is performed in the four-bottom-quark final state, using proton-proton collision data at 13 TeV corresponding to 138 fb - 1 collected by the CMS experiment at the LHC. The analysis targets Lorentz-boosted H pairs identified using a graph neural network. It constrains the strengths relative to the standard model of the H self-coupling and the quartic V V H H couplings, κ 2 V , excluding κ 2 V = 0 for the first time, with a significance of 6.3 standard deviations when other H couplings are fixed to their standard model values.