Search for new resonances decaying in the muon channel using the ATLAS detector

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"What is the universe made of?" This question, in appearance simple, has excited the minds of humans from time immemorial. Four fundamental forces of Nature are currently known: gravity, electromagnetism, and the strong and weak nuclear forces. While gravity is best described by Einstein's theory of General Relativity, the three other forces are described by the Standard Model of particle physics. These theories have proved very successful, in that they have passed experimental tests to an extremely high degree of accuracy. There is, however, strong theoretical and experimental evidence that our current models are incomplete. To give two examples, galaxies seem to contain much more matter than observed, and neutrinos, fundamental particles predicted to have no mass, in fact do. To address such discrepancies, new theories extend beyond the Standard Model, and the vast majority of them predict the existence of new forces. Such forces would manifest themselves through heavy force-carrying particles, which could be produced at very high energies. The Large Hadron Collider is the world's largest particle accelerator, and was designed to probe such energy scales. This project will analyze data from ATLAS, one of the two general-purpose detectors at the LHC, to search for new force-carrying particles. Being very heavy, these new particles would decay promptly into observable particles, but their presence or absence will be inferred from the trajectories of those decay products. The discovery of a new force of Nature would have a profound impact on our understanding of the universe at the most fundamental level. On the other hand, in the absence of a discovery, new exclusion limits will be set, signifying more stringent bounds on physics beyond the Standard Model. Either way, this project will contribute to the advancement of knowledge about what constitutes the world we live in.