Photoproduction of scalar mesons, and upgrade of the CLAS electromagnetic calorimeter at Jefferson Lab

Shloka Chandavar, Ohio University
Thursday, Jun 30, 11:00 AM - Special Seminar
1221A FRIB Laboratory

Abstract:  The standard quark model makes no allowance for the existence of gluons outside hadrons; however lattice QCD calculations predict bound states of two or more gluons, called glueballs. According to lattice calculations, the lightest of these experimentally unverified particles is expected to have mass in the range of 1 - 1.8 GeV and JPC = 0++. The mixing of glueball states with neighbouring meson states complicates their identification. The f0(1500) is one of several candidates for the lightest glueball, whose presence in the K0K0 channel was investigated in s s photoproduction using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. This was done by studying the reaction, /p ! fJ p ! K0K0p ! 2(⇡+⇡-)p using data from s s the g12 experiment. An angular analysis was performed on this data to characterize the spin properties of the resonance observed at 1.5 GeV. Results from the analysis of this data will be presented. The g12 experiment ran with the CLAS6 detector, so named because of its capability to work with a maximum electron beam energy of 6 GeV. Jefferson Lab has since upgraded its facility to produce electron beam with double that energy. This necessitated the update of the CLAS detector sub-systems in order to improve their functionality at higher energies. One of these upgrades is the preshower calorimeter (PCAL), which is to be placed in fromt of the CLAS6 electromagentic calorimeter. The construction and testing of the PCAL will be discussed.