Related papers: Are there eta-Helium bound states?
We argue that eta bound states in nuclei are sensitive to the singlet component in the eta. The bigger the singlet component, the more attraction and the greater the binding. Thus, measurements of eta bound states will yield new information…
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…
We present our recent results on the scattering length of ^4He-^4He_2 collisions. These investigations are based on the hard-core version of the Faddeev differential equations. As compared to our previous calculations of the same quantity,…
The existence of eta-mesic nuclei in which the eta meson is bound in a nucleus by means of the strong interaction was postulated already in 1986, albeit not yet confirmed it by experiment. The discovery of this new kind of an exotic nuclear…
We performed a search for 4He-eta bound state with high statistics and high acceptance with the WASA-at-COSY facility using a ramped beam technique. The signature of eta-mesic nuclei is searched for in dd -> 3Henpi0 and dd -> 3Heppi-…
We calculate the scattering lenths A(K-,3He) and A(K-,4He) using the multiple scattering approach and different parameters sets for the elementary a(Kbar,N). Within the zero-range approximation, we find for both systems loosely bound states…
The ^4He_3 bound states and the scattering of a ^4He atom off a ^4He dimer at ultra-low energies are investigated using a hard-core version of the Faddeev differential equations. Various realistic ^4He-^4He interactions were employed, amomg…
With the eta-nucleon (eta N) interaction Lagrangian deduced from chiral perturbation theory, we study the possible eta-mesic nuclei in the framework of relativistic mean-field theory. The eta single-particle energies are sensitive to the…
In a recent paper by the TAPS collaboration \cite{exp} a first measurement of a bound system of an $\eta$ meson and a ${^3}$He nucleus was reported. In this comment we critically reexamine the interpretation of the data and show that the…
We analyze the data on the total cross sections for the $dd \to \eta{}^4{\rm He}$ reaction close to threshold and look for possible $\eta ^4 {\rm He}$ bound states. We develop a framework in which the $\eta ^4{\rm He}$ optical potential is…
A microscopic treatment of $\eta$--nucleus scattering is presented. When applying the underlying exact integral equations, the excitation of the target are neglected, and an input $\eta N$ amplitude is chosen which reproduces the…
The connection of the binding energy and width of possible bound eta-mesic states is given to the complex scattering length for s-states in the hope that, with knowledge of the final state interaction this could be useful in searches of…
The mass of the {\eta}' meson is theoretically expected to be reduced at finite density, which indicates the existence of {\eta}'-nucleus bound states. To investigate these states, we perform missing-mass spectroscopy for the (p, d)…
The scattering length for the eta-meson collision with deuteron is calculated on the basis of rigorous few-body equations (AGS) for various eta-N input. The results obtained strongly support the existence of a resonance or quasi-bound state…
A model for the p d --> p d eta reaction published earlier, including the final state interaction (FSI) of all particles, is revisited to investigate the low energy data on this reaction. The three body problem of p-d-eta scattering in the…
The strong energy dependence of the s-wave eta-N scattering amplitude at and below threshold, as evident in coupled-channels K-matrix fits and chiral models that incorporate the S11 N*(1535) resonance, is included self-consistently in…
We report on precise hyperspherical-basis calculations of $\eta NN$ and $\eta NNN$ quasibound states, using energy dependent $\eta N$ interaction potentials derived from coupled-channel models of the $S_{11}$ $N^{\ast}(1535)$ nucleon…
The eta-mesic nuclei in which the eta meson is bound with nucleus via strong interaction was postulated about 25 years ago, however till now no experiment confirmed empirically its existence. The discovery of this new kind of an exotic…
The in-medium Eta-N interaction near and below threshold is constructed from a free-space chirally-inspired meson-baryon coupled-channel model that captures the physics of the N(1535) baryon resonance. Nucleon Pauli blocking and hadron…
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,…