arXiv subjects
Publications and source records attributed to Diane Schott.
The measurement was performed with circularly polarized photons incident on longitudinally polarized target in Hall B at the Thomas Jefferson National Accelerator Facility. The helicity asymmetry E for $\vecγ\vec{p}\toπ^0p$ was determined at CM energies between 1450 MeV and 2050 MeV and compared to the SAID, MAID, and BnGa partial-wave analyses.
We present an unitary dispersive model for the $η\to 3 π$ decay process based upon the Khuri-Treiman equations which are solved by means of the Pasquier inversion method. The description of the hadronic final-state interactions for the $η\to 3π$ decay is essential to reproduce the available data and to understand the existing discrepancies between Dalitz plot parameters from experiment and chiral perturbation theory. Our approach incorporates substraction constants that are fixed by fitting the recent high-statistics WASA-at-COSY data for $η\to π^+ π^- π^0$. Based on the parameters obtained we predict the slope parameter for the neutral channel to be $α=-0.022\pm 0.004$. Through matching to next-to-leading order chiral perturbation theory we estimate the quark mass double ratio to be $Q=21.4 \pm 0.4$.