Search for new heavy charged gauge bosons with the ATLAS detector

Particle physics deals with the most fundamental level at which nature can be understood. Experiments in high energy conditions allow for precise study and measurements of the structure and dynamics of matter. In particle colliders, such as the Large Hadron Collider (LHC) at CERN unprecedented center-of-mass energies can be achieved in proton-proton collisions. By recording the products of these collisions, the processes that occurred can be reconstructed. The ATLAS detector allows for detection and storage of vast numbers of collision events, and offers precise measurements of properties of the particles produced in these events. Using this approach, the Standard Model (SM) can be tested. This theoretical framework consists of a mathematical description of particle physics and allows for precise calculations and predictions. Even though the SM has proven to be highly successful, it does not explain everything observed in nature. Extensions of the SM can remedy this incompleteness. Using the same colliders, searches for these new phenomena can be conducted. This thesis describes the search for new heavy charged gauge bosons. These bosons, collectively referred to as W' bosons, would appear as resonance structures on top of the expectation from the SM alone. Searches of this kind have been carried out in previous experiments, but 2015 saw the first collisions at the highest center-of-mass energy of 13 TeV achieved at the time of writing. This analysis uses the entire data collected in 2015 and 2016. Interference effects between the hypothesized W' bosons and the charged W gauge bosons of the weak interaction in the SM are considered in this analysis. In the absence of a clear signal, upper limits on the relative coupling strength of new W' bosons can be calculated using a Bayesian statistics approach. These upper limits can be translated into a lower limit on the pole mass of the hypothesized boson under the assumption of a specific model. Below this pole mass the new particle can be excluded by the observed data at 95% confidence level.