Observation of the $p{\eta }^{\prime }$ Cusp in the New Precise Beam Asymmetry $\Sigma$ Data for $\gamma p\to p\eta$

TAPS Collaboration

Data on the beam asymmetry $\Sigma$ in the photoproduction of $\eta$ mesons off protons are reported for tagged photon energies from 1130 to 1790 MeV (mass range from $W=$ 1748 MeV to $W=$…