Deeply Bound Kaonic Clusters

Abstract

In this talk I make a review on the theoretical and experimental situation around the deeply bound kaon clusters, the possible bound kaonic states of nuclear, rather than atomic nature. At the same time I discuss novel developments around other kind of bound kaon clusters, which include states of two mesons and one baryon, with either one or two kaons, and states of a vector meson and two kaons, which explain naturally the observed properties of the X(2175) and Y(4260) resonances.

Selected topics on Hadrons in Nuclei

“…The K nucleus potential deduced from the in flight (K − , N ) reaction The issue of the K nucleus potential has also received much attention lately, with hopes that a sufficiently deep potential might lead to deeply bound kaon states. Recent updates of the experimental and theoretical situation can be seen in [22,23]. One has two extremes, one highly attractive phenomenological potential having a strength of about 600 MeV at the center of the nucleus, leading to nuclear densities ten times that of normal nuclear matter [24], and the more moderate potentials with a strength of about 50 MeV at normal nuclear matter density, which are obtained from chiral unitary approaches with selfconsistency [25,26,27,28,29].…”

“…All these potentials lead to deeply bound K − atoms, only that the chiral potentials produce states with a width too wide to lead to neat experimental peaks. While different experimental claims of deeply bound states have been ruled out, showing that the peaks observed have a conventional explanation in terms of theoretically controlled unavoidable reactions [22,23], a recent experiment claimed to have evidence that the depth of the potential was of the order of 200 MeV attractive at normal nuclear matter density [30]. The reaction is the in flight (K − , N ) process in nuclei using a beam of 1 GeV/c K − against a nuclear target of 12 C and looking at energetic protons or neutrons (500-700 MeV of kinetic energy) in the forward direction.…”