Dijet events are studied in the proton-proton collision data set recorded at √s=13 TeV with the ATLAS detector at the Large Hadron Collider in 2015 and 2016, corresponding to integrated luminosities of 3.5fb−1 and 33.5fb−1 respectively. Invariant mass and angular distributions are compared to background predictions and no significant deviation is observed. For resonance searches, a new method for fitting the background component of the invariant mass distribution is employed. The data set is then used to set upper limits at a 95% confidence level on a range of new physics scenarios. Excited quarks with masses below 6.0 TeV are excluded, and limits are set on quantum black holes, heavy W′ bosons, W∗ bosons, and a range of masses and couplings in a Z′ dark matter mediator model. Model-independent limits on signals with a Gaussian shape are also set, using a new approach allowing factorization of physics and detector effects. From the angular distributions, a scale of new physics in contact interaction models is excluded for scenarios with either constructive or destructive interference. These results represent a substantial improvement over those obtained previously with lower integrated luminosity.

Search for new phenomena in dijet events using 37 fb−1 of pp collision data collected at at √s=13 TeV with the ATLAS detector

G. L. Alberghi;L. Bellagamba;S. Biondi;D. Boscherini;A. Bruni;G. Bruni;G. D’amen;S. De Castro;F. Fabbri;L. Fabbri;M. Franchini;A. Gabrielli;B. Giacobbe;F. Lasagni Manghi;L. Massa;A. Mengarelli;A. Polini;L. Rinaldi;M. Romano;