Has a $ppK^{-}$ Signal in p+p Reactions been Observed Yet?

Our answer to the question posed in the title is: probably no. In this work we show that it is rather unlikely that the structure $X(2265)$ reported by the DISTO collaboration corresponds to a kaonic nuclear bound state. The main argumentation is based on the repetition of the DISTO analysis on the HADES data sample, containing p+p reactions at 3.5 GeV. We further discuss many aspects in connection with the $pK^{+}Lambda$ final state and the $Lambda(1405)$-resonance. The results evidence possible problematics in the interpretation of the DISTO data.

Investigation of the Lambda(1405) line shape observed in pp collisions

In this work we investigate different possible explanations for the observed low mass {Lambda}(1405) signal associated to the production of the {Lambda}(1405) in p+p reactions at 3.5 GeV beam kinetic energy measured by the HADES collaboration. We study the influence of interference effects between the {Lambda}(1405) resonance and the non-resonant background. Furthermore, we present a phenomenological method to use the HADES data for determining the relative contribution of the two {Lambda}(1405) poles and discuss to which extent the data can constrain the position of these poles in the complex energy plane.