Speaker
Description
Meson spectroscopy is the study of the properties and production and decay mechanisms of the mesons for the purpose of classification. Additionally, it is desirable to expand the spectrum of known mesons and to test the predictions of quantum chromodynamics, the theory of the strong force. Different types of mesons can be produced through high-energy electron-proton interactions where a meson resonance may be produced and then decay into two other mesons. If these two mesons are both spinless then the orbital angular momentum between them is equivalent to the total angular momentum of the parent meson. Quantities known as the partial wave amplitudes correspond to the different allowed values of the total orbital angular momentum. The experimental intensity of this reaction can be written in terms of these partial wave amplitudes which means they can be extracted from experimental data.
The reaction of interest is ep→epK+K- as the kaons are spinless and give rise to a range of possible spin resonances. In this analysis, data taken using CLAS12 at a beam energy of 10.2 GeV for Run Group A (Spring 2019) were used. CLAS12 was used to detect the final state particles, specifically the forward tagger was used to detect the scattered electron at angles 2.5-5.0° from the beamline. In this range, low-Q2 photoproduction reactions are induced in which the quasi-real photon retains a degree of linear polarisation. To ensure that epK+K- events were detected, various cuts were made on variables such as the particle time of flight and the electron energy. Variables including the polarization and polar angles in the Gottfried-Jackson frame were calculated. The S, P and D partial wave amplitudes were extracted by fitting the intensity using event-by-event maximum likelihood estimation and were acceptance-corrected using MC simulations.
