Cross Section and Tensor Analysing Power of the $\vec{d}d\to \eta \alpha$ Reaction Near Threshold

Abstract

The angular distributions of the unpolarised differential cross section and tensor analysing power $A_{xx}$ of the $\vec{d}d\to \alpha \eta$ reaction have been measured at an excess energy of 16.6 MeV. The ambiguities in the partial-wave description of these data are made explicit by using the invariant amplitude decomposition. This allows the magnitude of the s-wave amplitude to be extracted and compared with results published at lower energies. In this way, firmer bounds could be obtained on the scattering length of the $\eta \alpha$ system. The results do not, however, unambiguously prove the existence of a quasi-bound $\eta \alpha$ state.

arXiv comment20 pages, 11 figures

References in corpus (10)

• Big Bang Nucleosynthesis (in "The Review of Particle Properties" 2004)
• Near-Threshold Production of $\eta$-Mesons
• Precision study of the eta-3He system using the d+p->3He+eta reaction
• Measurement of the dp -->3He eta reaction near threshold
• Eta-Helium Quasi-Bound States
• $\eta$ bound states in nuclei
• Is there an eta-3He quasi--bound state ?
• Formation of $\eta$-mesic Nuclei Using the Recoilless (d,${}^3$He) Reaction
• Dependence of calculated binding energies and widths of $\eta$-mesic nuclei on treatment of subthreshold $\eta$-nucleon interaction
• Near threshold eta meson production in the d+d->alpha+eta reaction

Cited by in corpus (16)

• Coherent photoproduction of eta-mesons off 3He - search for eta-mesic nuclei
• Etaprime and Eta Mesons with Connection to Anomalous Glue
• Eta-nuclear bound states revisited
• Interaction of eta mesons with nuclei
• Search for Quasi Bound $\eta$ Mesons
• Study of the $\mathbf{p}{+}^6$Li$\to \mathbf{\eta }{+}^7$Be reaction 11.3 MeV above threshold
• Solution of the eta-4He problem with quasi-particle formalism
• Few-body aspects of the near threshold pseudoscalar meson production
• Eta-nuclear interaction: optical vs. coupled channels
• Status and Perspectives of the Search for Eta-Mesic Nuclei
• Measurement of the isospin-filtering dd -> 4He K+ K- reaction at Q=39 MeV
• Binding vs. scattering length: $\eta$ in light nuclei
• Systematic few-body analysis of eta-d, eta-3He and eta-4He interaction at low energies
• Status of the search for $\eta$-mesic nuclei with particular focus on $\eta$-Helium bound states
• Study of the eta meson production with polarized proton beam
• $\eta$ bound state: theory and experiment