相关论文: Three-body mechanism of $\eta$ production
The production of $\eta$ mesons in $NN$ collisions in the near threshold region is analyzed with special emphasis on the role of final state interaction which is calculated using three-body scattering theory. The three-body aspects are…
The differential cross sections of $pD\to ^3He X$ reactions, where $X=\eta, \ \eta'\ ,\omega, \ \phi $, are calculated on the basis of a two-step mechanism involving the subprocesses $pp\to d\pi ^+$ and $\pi^+n\to Xp $. It is shown that…
A study of the $\eta$-3N interaction in the energy region near the $\eta$-^3H elastic scattering threshold is presented. The calculational scheme is based on the four-body scattering formalism. A manageable form of the integral equations is…
The role of the $\eta NN$-interaction is studied in the low energy regime in $\eta$-deuteron reactions as well as in coherent and incoherent $\eta$-photoproduction on the deuteron using a three-body model with separable two-body…
A detailed study of the effect of the $\eta$-nucleus final state interaction (FSI) in the $p d \to ^3$He$ \eta$ reaction close to threshold is presented. The FSI is incorporated through a T-matrix for $\eta ^3$He elastic scattering,…
A study of the $p d \to p d \eta$ reaction in the energy range where the recent data from Uppsala are available, is done in the two-step model of $\eta$ production including the final state interaction. The $\eta -d$ final state interaction…
The optical potential approach for low-energy scattering of $\eta$-mesons on three-body nuclei is compared to an exact treatment of the $\eta 3N$ system using four-body scattering theory with separable interactions in s-waves only. The…
The amplitude of subthreshold phi-meson production is calculated using dominant tree-level diagrams for three-body collisions. It is shown that the production can overwhelmingly be described by two-step processes. The effect of the genuine…
The importance of three-body dynamics in the $\eta np$ system in elastic and inelastic $\eta$-deuteron scattering as well as coherent and incoherent $\eta$ photoproduction on the deuteron in the energy region from threshold up to 30 MeV…
Measurements of the differential and total cross sections for the $p d \to ^3$He $\eta$ reaction at five energies were recently reported [Phys. Rev. C {\bf 75}, 014004 (2007)] and comparisons with theoretical models were made. We point out…
The Alt-Grassberger-Sandhas N-body theory is used to study interaction of eta-mesons with d, 3He, and 4He. Separable expansion of the subamplitudes is adopted to convert the integral equations into the quasi-two-body form. The resulting…
A three-body calculation of the reaction $\gamma d\to\eta np$ in the energy region from threshold up to 30 MeV above has been performed. The primary goal of this study is to assess the importance of the three-body aspects in the hadronic…
It is argued that the strong energy dependence of the $p\, d \rightarrow \,^{3\!}H\!e\, \eta$ cross section near threshold is due to a final state interaction between the $\eta$ meson and the $^3$He nucleus. The large scattering length that…
Coherent photoproduction of $\eta$-mesons off $^3$He, i.e. the reaction $\gamma ^3{He}\rightarrow \eta ^3{He}$, has been investigated in the near-threshold region. The experiment was performed at the Glasgow tagged photon facility of the…
Measurements on the eta meson production in proton-deuteron collisions have been performed using the COSY-11 facility at COSY Juelich. Here we present preliminary results on total and differential cross sections for the pd --> 3He eta…
The production rate for \eta' in pp ->pp \eta' at rest is calculated in a covariant one boson exchange model, previously applied to study pi^0 and \eta production in NN collisions. The transition amplitudes for the elementary BN -> eta' N…
The cross section for the reaction $dd\rightarrow \,^4\!H\!e\,\eta$ close to threshold is estimated in a two-step model, similar to that which successfully describes near-threshold $pd\rightarrow \,^3\!H\!e\,\eta$ production. A $\pi$-meson,…
The cross sections for the $p p \to p p \eta$ reaction are evaluated at energies relevant for the HADES, PANDA, and SIS100 experiments at GSI-FAIR. Consideration includes the $\eta$-bremsstrahlung mechanism involving intermediate proton…
It is shown that the striking energy variation in the $p\, d \rightarrow \mbox{$^{\, 3}{\rm He}$}\, \eta$ cross section near threshold is probably due to a final state interaction associated with a large (complex) $\eta -\mbox{$^{3}{\rm…
A microscopic few-body description of near-threshold coherent photoproduction of the eta-meson on tritium and He3 targets is given. The photoproduction cross-section is calculated using the Finite Rank Approximation (FRA) of the nuclear…