Leptoquark phenomenology and the 4321 model

Extensions of the Standard Model of particle physics predict the existence of bosons that have both baryon and lepton number, the so-called leptoquarks. In this thesis, we explore the phenomenology of leptoquarks within the framework of one specific model dubbed the 4321 model, illustrating their theoretical motivations and experimental implications. The study begins with an introduction to the Standard Model with the aim of establishing the basis for subsequent investigations. Leptoquarks are then introduced and after a general discussion we focus onto the phenomenology of the 4321 model, analysing leptoquark decays and ditau production. Through detailed calculations and simulations, valuable insights into the behavior and observable features of the 4321 model are obtained. The implications of leptoquark decays and ditau lepton production are explored, providing potential signatures for experimental investigations. We then explore possible extensions to the current searches for leptoquarks and in particular the coloron decay is proposed. We find that in this case, it would useful to go to compute next-to-leading order corrections. In addition, we argue that knowing leptoquark pair production at next-to-leading order in QCD could be necessary in order to reach the needed control of production rates and kinematic properties. In conclusion, we provide a comprehensive and self-contained examination of the leptoquark phenomenology within the 4321 model. Our results show that this model is worth being studied and searched for in the data of the LHC experiments.