Near threshold production of the eta meson via the quasi-free pn --> pn eta reaction

Abstract

Total cross sections for the quasi-free pn --> pn eta reaction in the range from the kinematical threshold up to 20 MeV excess energy have been determined. At threshold they exceed corresponding cross sections for the pp --> pp eta reaction by a factor of about three in contrast to the factor of six established for higher excess energies. To large extent, the observed decrease of the ratio sigma(pn --> pn eta)/sigma(pp --> pp eta) towards threshold may be assigned to the different energy dependence of the proton-proton and proton-neutron final state interactions. The experiment has been conducted using a proton beam of the cooler synchrotron COSY and a cluster jet deuteron target. The proton-neutron reactions were tagged by the spectator proton whose momentum was measured for each event. Protons and neutron outgoing from the pn --> pn eta reaction have been registered by means of the COSY-11 facility, an apparatus dedicated for threshold meson production.

15 pages, 6 figures, submitted to Phys. Rev. C

References in corpus (6)

• Quasi-free photoproduction of eta-mesons of the neutron
• Precision measurement of the quasi-free pn->dphi reaction close to threshold
• Mechanism of the close-to-threshold production of the eta meson
• Coupling Constant for ${\mathbf{N}}^{\ast }(1535)\mathbf{N}\rho$
• Eta meson production in nucleon-nucleon collisions within an effective Lagrangian model
• Spectator detection for the measurement of proton neutron interactions at ANKE

Cited by in corpus (5)

• Study of the eta meson production with the polarised proton beam
• Anomalous glue, eta and eta-prime mesons
• Determination of the analysing power for the $\vec{p}p\to pp\eta$ reaction using WASA-at-COSY detector system
• Spin dependence of η meson production in proton-proton collisions close to threshold
• Studies of properties of the eta' meson at the COSY-11 facility