First measurement of the Sigma beam asymmetry in eta ' photoproduction off the proton near threshold

This record is in your EndNote library. Click to view it in my.endnote.com. First measurement of the Sigma beam asymmetry in eta ' photoproduction off the proton near threshold By: Sandri, P. Levi; Mandaglio, G.; De Leo, V.; et al. EUROPEAN PHYSICAL JOURNAL A Volume: 51 Issue: 7 Article Number: 77 Published: JUL 8 2015 Full Text from Publisher Close AbstractClose Abstract The Sigma beam asymmetry in eta' photoproduction off the proton was measured at the GrAAL polarised photon beam with incoming photon energies of 1.461 and 1.480 GeV. For both energies the asymmetry as a function of the meson production angle shows a clear structure, more pronounced at the lowest one, with a change of sign around 90 degrees. The observed behaviour is compatible with P-wave D-wave (or S-wave F-wave) interference, the closer to threshold the stronger. The results are compared to the existing state-of-the-art calculations that fail to account for the data.