Measurement of the Helicity Difference in γ[sup →]p[sup →]→pπ[sup +]π[sup −] with the CLAS Spectrometer at Jefferson Laboratory

The study of the properties of baryon resonances can provide us with hints to help us understand the structure of non‐perturbative QCD and the effect of a particular resonance on polarization observables. The investigation of double‐pion photoproduction data is needed to discover higher‐lying states and their properties at and above W ≈ 1.8 GeV. Therefore, the analysis of the helicity difference in gp γp→pπ+π− will help us in our understanding of QCD.The CLAS g9a (FROST) experiment, as part of the N* spectroscopy program at Jefferson Laboratory, has accumulated photoproduction data using linearly and circularly polarized photons incident on a longitudinally‐polarized butanol target in the photon energy range 0.3 to 2.4 GeV. The FROST experiment provides an important step toward a “complete” experiment for the reaction γN→KY. In this contribution, the method to calculate the helicity difference for the reaction γp→pπ+π− will be described and preliminary results will be discussed.