A study of the proton spectra following the capture of in 6Li and 12C with FINUDA

Kaon absorption in flight and the binding of K̄ in nuclei

“…Originally a narrow peak was reported in [16] which was associated to kaon absorption by two nucleons in [11]. This latter paper predicted that the peak should be seen in medium size nuclei and gradually disappear for heavier nuclei, and this was confirmed in [18]. The revision of the experiment of [16] in [17], showed that the original peak became a broad bump, in agreement with the estimated theoretical width reported in [13,14].…”

Search for a boundK−ppsystem

“…Further details about the detector and analysis techniques can be found in Refs. [19], [14] and references therein.…”

“…In particular, the tri-baryon state deduced from the 4 He(K − stop , p) spectrum, was assigned a binding energy B.E.=195 MeV and width Γ ≤ 25 MeV which were in good accordance with Akaishi and Yamazaki predictions. Such conclusion was later called into question by a measurement performed by the FINUDA experiment which observed the inclusive spectra of protons emitted from 6 Li targets, 6 Li(K − , p) [14]. Proton momentum spectra from 6 Li show a sizable signal at about 500 MeV/c [14] (see fig.1a)) which was interpreted as a proton emission after K − d → Σ − p two-body absorption on a "quasi-deuteron" subcluster of 6 Li.…”

“…Such conclusion was later called into question by a measurement performed by the FINUDA experiment which observed the inclusive spectra of protons emitted from 6 Li targets, 6 Li(K − , p) [14]. Proton momentum spectra from 6 Li show a sizable signal at about 500 MeV/c [14] (see fig.1a)) which was interpreted as a proton emission after K − d → Σ − p two-body absorption on a "quasi-deuteron" subcluster of 6 Li. Such interpretation was made possible by the capability of FINUDA of detecting also A(K − , π − p) coincidence events and determining particle emission vertices as well as πp kinematical correlations.…”

“…Such interpretation was made possible by the capability of FINUDA of detecting also A(K − , π − p) coincidence events and determining particle emission vertices as well as πp kinematical correlations. Inclusive proton spectra on 12 C [14] (see fig. 1b)) and other A>6 targets (up to A=61) presently under analysis show a much smoother behavior, incompatible with the hypothesis of the presence of narrow kaonic nuclear states.…”