Search for low mass resonances decaying into bottom quark-antiquark pairs in pp collisions at $\sqrt{s} = 13~\mathrm{TeV}$

A search for narrow scalar resonances decaying to bottom quark-antiquark pairs is presented. The search is based on events collected in $\sqrt{s}=13~\mathrm{TeV}$ proton-proton collisions with the CMS detector at the CERN LHC. The data sample, collected in 2016, corresponds to an integrated luminosity of $35.9~\mathrm{fb}^{-1}$. The resonance is produced with high transverse momentum due to initial state radiation, such that the decay products of the resonance are reconstructed as a single large-radius jet with high mass and two-pronged substructure. The signal is identified as a narrow excess in the jet invariant mass spectrum. No evidence for such a resonance is observed within the resonance mass range from $50$ to $350~\mathrm{GeV}$. Upper limits at the $95\%$ confidence level are set on the product of the cross section and branching fraction to a bottom quark-antiquark pair, constituting the first constraint from the LHC in this resonance mass range.