Search for resonant and non-resonant Higgs boson pair production in the $\mathrm{b}\overline{\mathrm{b}} \mathrm{l}\nu \mathrm{l}\nu$ final state at $\sqrt{s} = 13~\mathrm{TeV}$

Searches for resonant and non-resonant pair-produced Higgs bosons ($\mathrm{h}\mathrm{h}$) decaying respectively into $\mathrm{b}\overline{\mathrm{b}}$ and $\mathrm{V}\mathrm{V}$ (with $\mathrm{V}$ either a $\mathrm{W}$ or a $\mathrm{Z}$ boson), with subsequent $\mathrm{V}\mathrm{V}$ decays into two leptons and two neutrinos, are presented. The analyses are based on a sample of proton-proton collisions at $\sqrt{s} = 13~\mathrm{TeV}$ at the LHC corresponding to an integrated luminosity of $36~\mathrm{fb}^{-1}$. Data and predictions from the standard model are in agreement within uncertainties. For the standard model $\mathrm{h}\mathrm{h}$ hypothesis, the data are observed (expected) to exclude a production cross-section times branching ratio of $72~(81^{+42}_{-25})~\mathrm{fb}$, corresponding to $79$ ($89^{+47}_{-28}$) times the SM cross section. Lack of deviation from the SM predictions in the observations is used to place constraints on different scenarios considering anomalous couplings which could affect the rate and kinematics of $\mathrm{h}\mathrm{h}$ production. In the case of resonant production of a new particle $\mathrm{X}$, for mass hypotheses from ${\mathrm{m}}_{\mathrm{X}} = 300~\mathrm{GeV}$ to ${\mathrm{m}}_{\mathrm{X}} = 900~\mathrm{GeV}$, the data are observed (expected) to exclude a production cross-section times branching ratio of narrow-width spin-0 particles from $434$ to $17$ ($342^{+135}_{-97}$ to $14^{+6}_{-4}$)$~\mathrm{fb}$ and narrow-width spin-2 particles from $448$ to $14$ ($361^{+140}_{-102}$ to $13^{+5}_{-4}$)$~\mathrm{fb}$.