Triple Higgs boson production to six b-jets at a 100 TeV proton collider [Triple Higgs boson production to six b-jets at a 100 TeV proton collider: Anomalous self-couplings and gauge-singlet scalars]

We investigate the production of three Higgs bosons at a proton-proton collider running at a centre-of-mass energy of 100 TeV, all of which decay into b-jets. This final state encapsulates by far the largest fraction of the total cross section of triple Higgs boson production, approximately 20 %. We examine, by constructing detailed phenomenological analyses, two scenarios: (i) one in which the triple and quartic Higgs boson self-couplings are modified independently by new phenomena with respect to their Standard Model (SM) values and (ii) an extension of the SM by a gauge-singlet scalar that could drive first-order electroweak phase transition, within the context of the so-called xSM. In the former, we find that competitive constraints of O(1) can be placed on the quartic coupling and in the latter we demonstrate that it will be possible to obtain important information on the structure of the extended scalar sector.