Search for resonant and nonresonant production of pairs of dijet resonances with b jets in the final state in proton-proton collisions at $\sqrt{s}$ = 13 TeV

A search is presented for pair-produced dijet resonances of identical mass, each decaying into a bottom (b) quark and a light-flavor quark. The search uses a data sample corresponding to an integrated luminosity of 138 fb$^{-1}$ collected with the CMS detector in proton-proton collisions at $\\sqrt{s}=13$ TeV. Results are presented separately for nonresonant production and for the case where the four-jet production proceeds via an intermediate resonant state. Upper limits are reported on the production of four-jet and dijet resonances with b jets in the final state. This is the first LHC search for resonant production of pairs of fully resolved dijet resonances with b jets in the final state, in which all resonances considered correspond to non-standard-model states. For nonresonant production, the most significant excess occurs at an average dijet mass of 1.0 TeV, with a local significance of 2.1 standard deviations. Additionally, the results exclude pair production of top squarks with masses between 0.5 and 0.8 TeV, extending previous searches for $R$-parity-violating decays to strange and b quarks. In the search for resonant production, the most significant excess occurs at a four-jet resonance mass of 3.1 TeV and a dijet resonance mass of 1.3 TeV, with a local significance of 2.6 standard deviations. The results are also used to set limits at 95% confidence level on the diquark-to-diquarks model and exclude the heavier diquark masses between 2 and 7 TeV.