The Target Asymmetry P_z in γp → pπ~+ π~- with the CLAS Spectrometer at Jefferson Laboratory

摘要

The study of baryon resonances provides a deeper understanding of the strong interaction because the dynamics and relevant degrees of freedom hidden within them are reflected by the properties of the excited states of baryons. Higher-lying excited states at and above 1.9 GeV/c~2 are generally predicted to have strong couplings to the ππN final states via πΔ or ρN intermediate states. Double-pion photoproduction is therefore important to find and investigate properties of high-mass resonances. The CLAS g9a (FROST) experiment, as part of the N~* spectroscopy program at Jefferson Laboratory (JLab), has accumulated photoproduction data using linearly- and circularly-polarized photons incident on a longitually-polarized butanol target in the photon energy range 0.3 to 2.4 GeV. In this contribution, the extraction of the target asymmetry for the reaction γp → pπ~+π~-will be described and preliminary results will be presented.