Experimental issues on K[sup −] absorption by few nucleons and the search for Bound Kaonic Nuclear Systems

Abstract

Abstract. The available experimental data on K − absorption on nuclei are rather old and scarce and cannot help very much to understand whether the formation of composite objects made by kaons and many nucleons can occur.The existence of such structures is suggested by a few theoretical models, but many others do not expect them -or at least consider their experimental observation very difficult. The experimental study of their existence is based on the observation of hyperon-nucleon correlations, and on the features of the Λp(d,t) invariant mass distributions. If existing, in fact, these aggregates should non-mesonically decay in hyperon-nucleons final states, being the pionic channels forbidden due to energy conservation. Complementary information may also be gathered by the study of missing mass distributions.Recent experiments restarted the study of K − A absorption in light nuclei, namely on 4 He by KEK-E549, and on 6,7 Li, 9 Be and 12 C by FINUDA at DAΦNE.The experimental results obtained so far by the various experiments studying the K − absorption in nuclei are here summarized and presented.