7,931 research outputs found
In-medium nuclear interactions of low-energy hadrons
Experimental and theoretical developments of the last decade in the study of
exotic atoms and some related low-energy reactions are reviewed, in order to
provide information on the in-medium hadron-nucleon t matrix over a wide range
of densities up to central nuclear densities. In particular, we review pionic
deeply bound atomic states and related evidence for partial restoration of
chiral symmetry in dense nuclear matter. The case for relatively narrow deeply
bound atomic states for antikaons and antiprotons is made, based on the physics
of strong nuclear absorption. Recent experimental suggestions for signals of
antikaon-nuclear deeply bound states are reviewed, and dynamical models for
calculating binding energies, widths and densities of antikaon nuclear states
are discussed. Specific features of low-energy in-medium interactions of kaons,
antiprotons and of Sigma hyperons are discussed, and suggestions to study
experimentally Cascade atoms are reviewed.Comment: 86 pages, 44 figures, slight revisions, references added, Physics
Reports (in press
Few-body calculations of -nuclear quasibound states
We report on precise hyperspherical-basis calculations of and quasibound states, using energy dependent interaction potentials
derived from coupled-channel models of the nucleon
resonance. The attraction generated in these models is too weak to
generate a two-body bound state. No bound-state solution was found in
our calculations in models where Re fm, with the scattering length, covering thereby the majority of
resonance models. A near-threshold bound-state
solution, with separation energy of less than 1 MeV and width of about
15 MeV, was obtained in the 2005 Green-Wycech model where Re fm. The role of handling self consistently the subthreshold
interaction is carefully studied.Comment: a second footnote added in v2, matching published versio
Onset of -nuclear binding in a pionless EFT approach
and bound states are explored in stochastic
variational method (SVM) calculations within a pionless effective field theory
(EFT) approach at leading order. The theoretical input consists of regulated
and contact terms, and a regulated energy dependent contact
term derived from coupled-channel models of the nucleon
resonance plus a regulated contact term. A self consistency procedure
is applied to deal with the energy dependence of the subthreshold
input, resulting in a weak dependence of the calculated -nuclear binding
energies on the EFT regulator. It is found, in terms of the scattering
length , that the onset of binding \eta\,^3He requires a minimal
value of Re close to 1 fm, yielding then a few MeV binding
in \eta\,^4He. The onset of binding \eta\,^4He requires a lower value of
Re, but exceeding 0.7 fm.Comment: v4 consists of the published Physics Letters B version [31] plus
Erratum ([30], Appendix A here); main results and conclusions remain intac
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