A search for dijet resonances in proton-proton collisions at $\sqrt{s}=13~\mathrm{TeV}$ with a new background prediction method

Searches for narrow and broad resonances with a mass greater than $1.8~\mathrm{TeV}$ decaying to a pair of jets are presented using proton-proton collision data at $\sqrt{s}=13~\mathrm{TeV}$ corresponding to an integrated luminosity of $137$ fb$^{-1}$. The background arising from standard model processes is predicted using two complementary data-driven methods. The dijet invariant mass spectrum is well described by both methods, and no significant evidence for the production of new particles is observed. Model independent upper limits at $95\%$ confidence level are reported on the production cross section of narrow resonances, and broad resonances with widths up to $30\%$ of the resonance mass, extending previous searches. The limits are applied to various models of narrow resonances and exclude, at $95\%$ confidence level: string resonances with masses below $7.9~\mathrm{TeV}$, scalar diquarks below $7.5~\mathrm{TeV}$, axigluons and colorons below $6.6~\mathrm{TeV}$, excited quarks below $6.3~\mathrm{TeV}$, color-octet scalars below $3.7~\mathrm{TeV}$, $W^{\prime}$ bosons below $3.6~\mathrm{TeV}$, $Z^{\prime}$ bosons with SM-like couplings below $2.9~\mathrm{TeV}$ and between $3.1~\mathrm{TeV}$ and $3.3~\mathrm{TeV}$, Randall--Sundrum Gravitons below $2.6~\mathrm{TeV}$ TeV, and dark matter mediators below $2.8~\mathrm{TeV}$. Limits on dark matter mediators are presented as a function of resonance mass and width, and equivalently coupling, which exclude at $95\%$ confidence level a dark matter mediator with mass less than $4.7~\mathrm{TeV}$ for a width equal to $25\%$ of the mass.