학술논문
Study of $\eta$ and $\eta'$ photoproduction at MAMI
Document Type
Working Paper
Author
Kashevarov, V. L.; Ott, P.; Prakhov, S.; Adlarson, P.; Afzal, F.; Ahmed, Z.; Akondi, C. S.; Annand, J. R. M.; Arends, H. J.; Beck, R.; Braghieri, A.; Briscoe, W. J.; Cividini, F.; Codling, R.; Collicott, C.; Costanza, S.; Denig, A.; Downie, E. J.; Dieterle, M.; Bondy, M. I. Ferretti; Filkov, L. V.; Fix, A.; Gardner, S.; Garni, S.; Glazier, D. I.; Glowa, D.; Gradl, W.; Gurevich, G.; Hamilton, D. J.; Hornidge, D.; Howdle, D.; Huber, G. M.; Kaeser, A.; Kay, S.; Keshelashvili, I.; Kondratiev, R.; Korolija, M.; Krusche, B.; Linturi, J.; Lisin, V.; Livingston, K.; MacGregor, I. J. D.; MacRae, R.; Mancell, J.; Manley, D. M.; Martel, P. P.; McGeorge, J. C.; McNicol, E.; Middleton, D. G.; Miskimen, R.; Mornacchi, E.; Mullen, C.; Mushkarenkov, A.; Neiser, A.; Oberle, M.; Ostrick, M.; Otte, P. B.; Oussena, B.; Paudyal, D.; Pedroni, P.; Polyanski, V. V.; Rajabi, A.; Robinson, J.; Rosner, G.; Rostomyan, T.; Sarty, A.; Schott, D. M.; Schumann, S.; Sfienti, C.; Sokhoyan, V.; Spieker, K.; Steffen, O.; Strandberg, B.; Strakovsky, I. I.; Strub, Th.; Supek, I.; Taragin, M. F.; Thiel, A.; Thiel, M.; Tiator, L.; Thomas, A.; Unverzagt, M.; Wagner, S.; Watts, D. P.; Werthmueller, D.; Wettig, J.; Witthauer, L.; Wolfes, M.; Workman, R. L.; Zana, L.
Source
Phys. Rev. Lett. 118, 212001 (2017)
Subject
Language
Abstract
The reactions $\gamma p\to \eta p$ and $\gamma p\to \eta' p$ have been measured from their thresholds up to the center-of-mass energy $W=1.96$GeV with the tagged-photon facilities at the Mainz Microtron, MAMI. Differential cross sections were obtained with unprecedented accuracy, providing fine energy binning and full production-angle coverage. A strong cusp is observed in the total cross section and excitation functions for $\eta$ photoproduction at the energies in vicinity of the $\eta'$ threshold, $W=1896$MeV ($E_\gamma=1447$MeV). This behavior is explained in a revised $\eta$MAID isobar model by a significant branching of the $N(1895)1/2^-$ nucleon resonance to both, $\eta p$ and $\eta' p$, confirming the existence and constraining the properties of this poorly known state.