Search for Higgs boson pair production in the four b quark final state

A search for the production of pairs of Higgs bosons in proton-proton collisions at a centre-of-mass energy of $13~\mathrm{TeV}$ is presented, using a data sample collected with the CMS detector at the LHC and corresponding to an integrated luminosity of about $138\,\mathrm{fb}^{-1}$. The search investigates both the gluon and vector boson fusion production mechanisms for Higgs boson pairs in the final state with four b quarks. No evidence of signal is found, and an observed (expected) upper limit on the Higgs boson pair production cross section of 3.6 (7.3) times the standard model prediction is set. Results are also interpreted under assumptions involving anomalous Higgs boson couplings. At a $95\%$ confidence level, the Higgs field self-coupling is constrained to be within -2.3 and 9.4 times the standard model expectation, and the coupling of two Higgs bosons to two vector bosons is constrained to be within -0.1 and 2.2.