First Measurement of a0 2(1320) Polarized Photoproduction Cross Section First Measurement of a0 2(1320) Polarized Photoproduction Cross Section

We measure for the first time the differential photoproduction cross section dσ/dt of the a2(1320) meson at an average photon beam energy of 8.5 GeV, using data with an integrated luminosity of 104 pb−1 collected by the GlueX experiment. We fully reconstruct the γp→ηπ0preaction and perform a partial-wave analysis in the a2(1320) mass region with amplitudes that incorporate the linear polarization of the beam. This allows us to separate for the first time the contributions of natural- and unnatural-parity exchanges. These measurements provide novel information about the photoproduction mechanism, which is critical for the search for spin-exotic states.