In-medium nuclear interactions of low-energy hadrons

Abstract

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

K−N amplitudes below threshold constrained by multinucleon absorption

“…This result is not new, as previous analyses have shown the need to include phenomenological terms motivated by K − multinucleon processes, V (2) K − , in order to obtain agreement with experiment [5,6]. Equally good fits of χ 2 per point of less than 2 could also be achieved with purely phenomenological forms for V K − [9,10]. At the next stage, we add to the single-nucleon part…”

“…The level width Γ which is usually obtained from the complex eigenvalue E K − −iΓ/2 when solving the Klein-Gordon equation with an optical potential V K − [10], is also related to the imaginary part of the potential by the overlap integral of Im V K − and |ψ| 2 ,…”

“…The wave functions were calculated from a best-fit phenomenological potential denoted DD in Ref. [10]. The upper panel of the figure shows the relative density distributions for these examples.…”

“…As in earlier publications [9,10] the present work deals with global analyses of kaonic atoms, handling together experimental results along the periodic table in order to gain insight on average properties of the K − -nucleus interaction near threshold. Table 1 shows values of χ 2 for 65 kaonic atoms data points for an optical potential V (1) K − (ρ) constructed from Eq.…”

“…For lack of accepted microscopic theory, this approach cannot be applied to the multinucleon part V (2) K − (ρ) of V K − (ρ), which usually consists of phenomenological terms devised to achieve agreement with experiment, as reviewed in Refs. [9,10].…”