Observation of a structure in the M-p eta invariant mass distribution near 1700 MeV/c(2) in the gamma p -> p pi(0)eta reaction

Metag, V. and Nanova, M. and Hartmann, J. and Mahlberg, P. and Afzal, F. and Bartels, C. and Bayadilov, D. and Beck, R. and Becker, M. and Blanke, E. and Brinkmann, K. -t. and Ciupka, S. and Crede, V. and Dieterle, M. and Dutz, H. and Elsner, D. and Frommberger, F. and Gridnev, A. and Gottschall, M. and Gruner, M. and Hammann, Ch. and Hannappel, J. and Hillert, W. and Hoff, J. and Hoffmeister, Ph. and Honisch, Ch. and Jude, T. and Kalinowsky, H. and Kalischewski, F. and Keshelashvili, I. and Ketzer, B. and Klassen, P. and Klein, F. and Koop, K. and Kroenert, P. and Krusche, B. and Lang, M. and Lopatin, I. and Messi, F. and Meyer, W. and Mitlasoczky, B. and Muller, J. and Muellers, J. and Nikonov, V. and Novinsky, V. and Novotny, R. and Piontek, D. and Reicherz, G. and Richter, L. and Rostomyan, T. and Runkel, S. and Salisbury, B. and Sarantsev, A. and Schaab, D. and Schmidt, Ch. and Schmieden, H. and Schultes, J. and Seifen, T. and Sokhoyan, V. and Sowa, C. and Spieker, K. and Stausberg, N. and Thiel, A. and Thoma, U. and Triffterer, T. and Urban, M. and Urff, G. and van Pee, H. and Wagner, M. and Walther, D. and Wendel, Ch. and Werthmueller, D. and Wiedner, U. and Wilson, A. and Winnebeck, A. and Witthauer, L. and Wunderlich, Y.. (2021) Observation of a structure in the M-p eta invariant mass distribution near 1700 MeV/c(2) in the gamma p -> p pi(0)eta reaction. European Physical Journal A: Hadrons and Nuclei , 57 (12). p. 325.

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The reaction gamma p -> p pi(0)eta has been studied with the CBELSA/TAPS detector at the electron stretcher accelerator ELSA in Bonn for incident photon energies from threshold up to 3.1 GeV. This paper has been motivated by the recently claimed observation of a narrow structure in the MN n invariant mass distribution at a mass of 1678 MeV/c(2). The existence of this structure cannot be confirmed in the present work. Instead, for E-gamma = 1400-1500 MeV and the cut M-P pi(0) <= 1190 MeV/c(2) a statistically significant structure in the M-p eta invariant mass distribution near 1700 MeV/c(2) is observed with a width of Gamma approximate to 35 MeV/c(2) while the mass resolution is sigma(res) = 5 MeV/c(2). Increasing the incident photon energy from 1420 to 1540 MeV this structure shifts in mass from approximate to 1700 MeV/c(2) to approximate to 1725 MeV/c(2); the width increases to about 50 MeV/c(2) and decreases thereafter. The cross section associated with this structure reaches a maximum of approximate to 100 nb around E gamma approximate to 1490 MeV (W approximate to 1920 MeV), which coincides with the pa(0) threshold. Three scenarios are discussed which might be the origin of this structure in the M-p eta invariant mass distribution. The most likely interpretation is that it is due to a triangular singularity in the gamma p -> pa(0) -> p pi(0)eta reaction.
Faculties and Departments:05 Faculty of Science > Departement Physik > Physik > Hadronenphysik (Krusche)
UniBasel Contributors:Krusche, Bernd
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:EDP Sciences with Springer and Società Italiana di Fisica
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:12 Apr 2022 07:04
Deposited On:12 Apr 2022 07:04

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