Search for new phenomena in dijet mass and angular distributions from ppcollisions at √s = 13 TeV with the ATLAS detector

This Letter describes a model-agnostic search for pairs of jets (dijets) produced by resonant and non-resonant phenomena beyond the Standard Model in 3.6fb−1of proton–proton collisions with a centre-of-mass energy of √s=13TeVrecorded by the ATLAS detector at the Large Hadron Collider. The distribution of the invariant mass of the two leading jets is examined for local excesses above a data-derived estimate of the smoothly falling prediction of the Standard Model. The data are also compared to a Monte Carlo simulation of Standard Model angular distributions derived from the rapidity of the two jets. No evidence of anomalous phenomena is observed in the data, which are used to exclude, at 95% CL, quantum black holes with threshold masses below 8.3TeV, 8.1TeV, or 5.1TeVin three different benchmark scenarios; resonance masses below 5.2TeVfor excited quarks, 2.6TeVin a W model, a range of masses starting from mZ =1.5TeVand couplings from gq=0.2in a Z model; and contact interactions with a compositeness scale below 12.0TeVand 17.5TeVrespectively for destructive and constructive interference between the new interaction and QCD processes. These results significantly extend the ATLAS limits obtained from 8 TeV data. Gaussian-shaped contributions to the mass distribution are also excluded if the effective cross-section exceeds values ranging from approximately 50–300fb for masses below 2TeVto 2–20fb for masses above 4TeV