Production of ${a_0}-mesons$ in the reactions ${\pi N \to a_0 N}$ and ${p p \to d a_0^+}$ at GeV energies

V.Yu. Grishina; L.A. Kondratyuk; E.L. Bratkovskaya; M. Büscher; W. Cassing

doi:doi:10.1007/s100500070045

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2023 Impact factor 2.6

Hadrons and Nuclei

Eur. Phys. J. A 9, 277-285

Production of a₀-mesons in the reactions ${\pi N \to a_0 N}$ and ${p p \to d a_0^+}$ at GeV energies

V.Yu. Grishina¹ - L.A. Kondratyuk² - E.L. Bratkovskaya³ - M. Büscher⁴ - W. Cassing³

¹ Institute for Nuclear Research, 60th October Anniversary Prospect 7A, 117312 Moscow, Russia
² Institute of Theoretical and Experimental Physics, B.Cheremushkinskaya 25, 117259 Moscow, Russia
³ Institut für Theoretische Physik, Universität Giessen, D-35392 Giessen, Germany
⁴ Institut für Kernphysik, Forschungszentrum Jülich, D-52425 Jülich, Germany

Received: 4 August 2000
Communicated by W. Weise

Abstract
We investigate the reactions ${\pi N \to a_0 N}$ and ${p p \to d a_0^+}$ near threshold and at medium energies. An effective Lagragian approach and the Regge pole model are applied to analyze different contributions to the cross-section of the reaction ${\pi N \to a_0 N}$ . These results are used to calculate the differential and total cross-sections of the reaction ${p p \to d a_0^+}$ within the framework of the two-step model in which two nucleons produce an a₀-meson via $\pi$ -meson exchange and fuse to a deuteron. The necessity of new measurements on a₀ production and branching fractions (of its decay to the $K\bar K$ and $\pi\eta$ channels) is emphasized for clarifying the a₀ structure. Detailed predictions for the reaction $pp \rightarrow d a_0^+$ are presented for the energy regime of the proton synchrotron COSY-Jülich.