L. Tiator, M. Gorchtein, V. L. Kashevarov, K. Nikonov, M. Ostrick, M. Hadžimehmedović, R. Omerović, H. Osmanović, J. Stahov, A. Švarc
The European Physical Journal A
Received 13 July 2018, Accepted 20 October 2018. First Online 06 December 2018
DOI https://doi.org/10.1140/epja/i2018-12643-x
Publisher Name Springer Berlin Heidelberg
Print ISSN 1434-6001 Online ISSN 1434-601X
The isobar model EtaMAID has been updated with new and high precision data for 𝜂 and 𝜂′ photoproduction on protons and neutrons from MAMI, ELSA, GRAAL and CLAS. The background is described in a recently developed Regge cut model, and for the resonance part the whole list of nucleon resonances has been investigated with 21 𝑁∗ states contributing to 𝜂 photoproduction and 12 𝑁∗ states contributing to 𝜂′ photoproduction. A new approach is discussed to avoid double counting in the overlap region of Regge and resonances. A comparison is done among four newly updated partial waves analyses for observables and partial waves. Finally, the possibility of a narrow resonance near 𝑊=1900 MeV is discussed, that would be able to explain unexpected energy and angular dependence of observables in 𝑝(𝛾,𝜂′)𝑝 near 𝜂′ threshold.
The European Physical Journal A
Received 13 July 2018, Accepted 20 October 2018. First Online 06 December 2018
DOI https://doi.org/10.1140/epja/i2018-12643-x
Publisher Name Springer Berlin Heidelberg
Print ISSN 1434-6001 Online ISSN 1434-601X
The isobar model EtaMAID has been updated with new and high precision data for 𝜂 and 𝜂′ photoproduction on protons and neutrons from MAMI, ELSA, GRAAL and CLAS. The background is described in a recently developed Regge cut model, and for the resonance part the whole list of nucleon resonances has been investigated with 21 𝑁∗ states contributing to 𝜂 photoproduction and 12 𝑁∗ states contributing to 𝜂′ photoproduction. A new approach is discussed to avoid double counting in the overlap region of Regge and resonances. A comparison is done among four newly updated partial waves analyses for observables and partial waves. Finally, the possibility of a narrow resonance near 𝑊=1900 MeV is discussed, that would be able to explain unexpected energy and angular dependence of observables in 𝑝(𝛾,𝜂′)𝑝 near 𝜂′ threshold.
