Is there an eta-3He quasi--bound state ?

Abstract

The observed variation of the total cross section for the dp -> 3He eta reaction near threshold means that the magnitude of the s--wave amplitude falls very rapidly with the eta centre--of--mass momentum. It is shown here that recent measurements of the momentum dependence of the angular distribution imply a strong variation also in the phase of this amplitude. Such a behaviour is that expected from a quasi--bound or virtual eta-3He state. The interpretation can be investigated further through measurements of the deuteron or proton analysing powers and/or spin--correlations.

10 pages with two eps figures

References in corpus (10)

• Photoproduction of eta-mesic 3He
• Near-Threshold Production of $\eta$-Mesons
• Precision study of the eta-3He system using the d+p->3He+eta reaction
• pi N --> eta N and eta N --> eta N partial wave T-matrices in a coupled, three channel model
• Measurement of the dp -->3He eta reaction near threshold
• Hadronic Spectral Functions in Nuclear Matter
• $\eta$ bound states in nuclei
• Bounds on the bound η^3He system
• Comment on 'Photoproduction of $\eta$--Mesic ${}^3$He'
• The $\eta {-}^3$He scattering length revisited

Cited by in corpus (36)

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• Precision study of the d+p->3He+eta reaction for excess energies between 20 and 60 MeV
• Absence of spin dependence in the final state interaction of the d(pol) p --> 3He eta reaction
• Search for Quasi Bound $\eta$ Mesons
• Constraining the optical potential in the search for eta-mesic 4He
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• Search for the 3He-eta bound state at COSY-11
• Interference and nuclear medium effects on the eta-mesic nuclear spectrum
• Upper limits for the production of the eta-mesic Helium in the dd ->3Henpi0 and dd -> 3Heppi- reactions
• Few-body aspects of the near threshold pseudoscalar meson production
• Total and differential cross sections of $\eta$-production in proton-deuteron fusion for excess energies between $Q_{\eta }=13\text{MeV}$ and $Q_{\eta }=81\text{MeV}$
• Status and Perspectives of the Search for Eta-Mesic Nuclei
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• Structure of double pionic atoms
• The legacy of the experimental hadron physics programme at COSY
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• Theoretical study of the $\gamma d\to {\pi }^0\eta d$ reaction
• Search for the eta-mesic Helium bound state with the WASA-at-COSY facility
• Study of the eta meson production with polarized proton beam
• Search for the 4He-eta bound state in dd->(4He-eta)_{bound}->3He n pi0 and dd->(4He-eta)_{bound}->3He p pi- reactions with the WASA-at-COSY facility
• Search for eta-mesic 3He in non-mesonic final states
• Total and differential cross sections of the $\mathbf{dp}\to {}^3\text{He}\mathbf{\eta }$ reaction at excess energies between 1 and 15 MeV
• Non-Strange Meson Production with Hadronic Probes
• Close to threshold eta' meson production in proton-proton collisions at COSY-11