Searches for dijet resonances in pp collisions at $\sqrt{s}=13~\mathrm{TeV}$ using data collected in 2016.

Searches are presented for narrow resonances decaying to dijet final states in proton-proton collisions at $\sqrt{s}=13~\mathrm{TeV}$. A low-mass search, for a resonance mass between 0.6 TeV and 1.6 TeV, is performed using dijets that are reconstructed from calorimeter information in the trigger using data corresponding to an integrated luminosity of $27~\mathrm{fb}^{-1}$. A high-mass search, for resonances with mass above 1.6 TeV, is performed using dijets reconstructed with the particle flow algorithm from the normal reconstruction chain using data corresponding to an integrated luminosity of $36~\mathrm{fb}^{-1}$. The dijet mass spectrum is well described by a smooth parameterization and no significant evidence for the production of new particles is observed. Upper limits at $95\%$ confidence level are reported on the production cross section for narrow resonances with masses above 0.6 TeV. In the context of specific models, the limits exclude string resonances with masses below 7.7 TeV, scalar diquarks below 7.2 TeV, axigluons and colorons below 6.1 TeV, excited quarks below 6.0 TeV, color-octet scalars below $3.4~\mathrm{TeV}$, W$^{\prime}$ bosons below 3.3 TeV, Z$^{\prime}$ bosons below 2.7 TeV, RS gravitons below $1.7~\mathrm{TeV}$ and between 2.1 and 2.5 TeV, and dark matter mediators below 2.6 TeV. The limits on both vector and axial-vector mediators, in a simplified model of interactions between quarks and dark matter, are also presented as functions of dark matter mass. These extend previous limits in the dijet channel.