Total and differential cross sections of the $\mathbf{dp}\to {}^3\text{He}\mathbf{\eta }$ reaction at excess energies between 1 and 15 MeV

Abstract

New high precision total and differential cross sections are reported for the $dp\to {}^3\text{He}\eta$ reaction close to threshold. The measurements were performed using the magnetic spectrometer ANKE, which is an internal fixed target facility at the COSY cooler synchrotron. The data were taken for deuteron beam momenta between $3.14641\text{GeV}/c$ and $3.20416\text{GeV}/c$, which corresponds to the range in excess energy $Q$ for this reaction between $1.14\text{MeV}$ and $15.01\text{MeV}$. The normalization was established through the measurement in parallel of deuteron-proton elastic scattering and this was checked through the study of the $dp\to {}^3\text{He}{\pi }^0$ reaction. The previously indicated possible change of sign of the slope of the differential cross sections near the production threshold, which could be explained by a rapid variation of the $s$- and $p$-wave interference term, is not confirmed by the new data. The energy dependence of the total cross section and the $90^{\circ }$ slope parameter are well explained by describing the final state interaction in terms of a complex Jost function and the results are significant in the discussion of $\eta$-mesic nuclei. In combination with recently published WASA-at-COSY data [P. Adlarson $etal.$, Phys. Lett. B 782, 297 (2018)], a smooth variation of the slope parameter is achieved up to an excess energy of $80.9\text{MeV}$.

arXiv comment12 pages, 11 figures, preprint submitted to Physical Review C

References in corpus (14)

• 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
• Measurement of the dp -->3He eta reaction near threshold
• Eta-Helium Quasi-Bound States
• Coherent photoproduction of eta-mesons off 3He - search for eta-mesic nuclei
• Is there an eta-3He quasi--bound state ?
• Search for eta-mesic 4He in the dd->3He n pi0 and dd->3He p pi- reactions with the WASA-at-COSY facility
• Determination of the ${\mathbf{\eta }}^3\mathrm{He}$ threshold structure from the low energy $\mathbf{pd}\to {\mathbf{\eta }}^3\mathrm{He}$ reaction
• Precision study of the d+p->3He+eta reaction for excess energies between 20 and 60 MeV
• New determination of the mass of the eta meson at COSY-ANKE
• High precision beam momentum determination in a synchrotron using a spin resonance method
• Total and differential cross sections of $\eta$-production in proton-deuteron fusion for excess energies between $Q_{\eta }=13\text{MeV}$ and $Q_{\eta }=81\text{MeV}$
• Experimental and theoretical study of deuteron-proton elastic scattering for proton kinetic energies between $T_p=882.2\text{MeV}$ and $T_p=918.3\text{MeV}$