Spin-Density Matrix Elements in K^*(892) Photoproduction with Recoiling Λ at GlueX

We report on the ongoing analysis of spin-density matrix elements for the K^*(892) → K⁺ π⁰ photoproduction process with a recoiling Λ hyperon. The measurement uses high-statistics GlueX data from photoproduction off a proton target at photon energies between 8.2 and 8.8 GeV, in a kinematic regime dominated by t-channel exchange processes. GlueX is a fixed-target experiment with a linearly polarized photon beam and a nearly 4π hermetic detector, allowing extraction of the full spin observables from both the K⁺ π⁰ and Λ → π^- p systems. The GlueX data show clear evidence of the K^*(892) resonance in the K⁺ π⁰ mass spectrum, along with additional structures at higher masses that may correspond to K^*₀ or K^*₂ resonances. The precise measurement of the spin-density matrix elements of the K^*(892) could serve as a standard candle for continuing studies of higher-mass excited K^* states. In addition, t-channel K^* photoproduction differs from previous measurements of non-strange vector meson photoproduction, as it is free from Pomeron exchange and is virtually unexplored in this energy regime. Furthermore, the unprecedented data collected by GlueX allow for investigations of correlations between the Λ polarization and the spin-density matrix elements of K^* production, paving the way for future partial-wave analyses with full spin information involving the recoil hyperon.