Search for New Particles Decaying to Hadronic Jets in Proton-Proton Collision at $\sqrt{s} = 13$ TeV

This thesis presents a search for new resonances decaying to pairs of jets in $37 \mathrm{fb^{-1}}$ of proton-proton collision data produced by the Large Hadron Collider at a center-of-mass energy of $13$ TeV. The data was collected in $2015$ and $2016$ by the ATLAS detector. A new resonance search algorithm - SWiFt - was used to reduce the uncertainty in the data-driven estimate of the unknown backgrounds. SWiFt was utilized in a model-independent search, and also to perform model-dependent searches for excited quarks ($q^*$) and heavy gauge bosons ($W′$). No evidence for new phenomena was observed, so $95\%$ confidence-level upper limits were calculated on the production rates of $q^*$ and $W′$. Upper limits were also calculated for Gaussian models which represent first-order approximations for many theoretical models that predict new particles decaying to two jets.