Searches for Exotic Mesons at CLAS12

The Standard Model proposes the quarks, leptons and bosons to account for all matter and nearly all the fundamental forces. With the existence and expected behaviour of these particles experimentally confirmed, the Standard Model is highly successful and is the leading theory of elementary particle physics. The hadrons are a family of composite particles comprised of the mesons and the baryons which can be modelled as bound states of quarks. The constituent quark model describes mesons as quark-antiquark pairs and baryons as three quarks; it’s a simple but successful model, accounting for almost all of the experimentally confirmed hadrons. Quantum chromodynamics (QCD), the theory of the strong force belonging to the Standard Model, develops on the constituent quark model by introducing the strong force mediator particle known as the gluon. As a result, QCD predicts additional hadrons which are termed exotics. The subject of the research presented in this thesis is to search for exotic mesons produced in electron-proton scattering at CLAS12 at Jefferson Lab. The ep → epK+K− reaction was chosen as the reaction of interest. By using the CLAS12 Forward Tagger, reactions were chosen with electrons scattering at low angles so that a quasi-real photon mediated the electron-proton interaction. During this interaction, various types of mesons are produced which all contribute to the final state of the reaction of interest. Several analysis techniques were applied to the experimental data to ensure that only the reaction of interest was studied. Moments of angular distribution were obtained and are presented in this thesis. These distributions show the contributions of different types of mesons to the final state, meaning that signatures of non-exotic and exotic mesons can be observed.