[en] Applications of different approaches to the description of the Pontecorvo reaction at rest and in flight are considered

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[en] The main characteristics of the multipurpose ALFA 3 Project are presented. The two previous Proposals ALFA 1 and ALFA 2 are also revisited and discussed

[en] A pion or a kaon may behave as a leading particle in low-energy antiproton-nucleus reactions, in agreement with a quark model picture describing beam fragmentation

[en] The recent experimental results on antiproton-nucleus interaction at intermediate energies are consistent with the predictions of the intranuclear cascade (INC) models. However, there is an increasing number of ''cases'' which cannot be explained within the conventional framework, indicating the possible evidence of unusual annihilations. The physical meaning of unusual (multinucleon) annihilations is stressed. Reactions which can favour multinucleon annihilations, specifically Pontecorvo reactions, are examined. The theoretical models which deal with multinucleon annihilations are recalled, together with the specific signatures, in particular strangeness enhancement. Finally, all the possible experimental evidences, up to now, of unusual annihilations are reported and discussed. (author). 47 refs, 4 figs, 2 tabs

[en] Bag models predict a six-quark system, a SU(3)_f singlet configuration of structure (uu dd ss) with all six quarks in the 1s groundstate and quantumnumbers J^π = 0⁺ and isospin T = 0, to be stable against strong decays due to its high symmetry which gives enough colormagnetic attraction for the mass to lie below ΛΛ threshold. This object - dubbed the H particle - is viewed in the quark model and as a dibaryon system with meson exchange forces (sect. 2). Section 3 deals with the mode decay and lifetime. Possible reactions with S = -2 exchange for producing these H particles are discussed in sections 4 and 6. In sect. 5 the existence of the H particle in relation to the observation of hypernuclei is discussed. The last sections deal with future experimental programs on the H particle and the case of Cygnus X-3, from which such particles are presumed to be emitted. 46 refs.; 15 figs.; 1 table. (H.W.)

[en] In Section 2 we report the more recent results in antiproton-nucleus annihilation, and we discuss new or peculiar aspects of some of them. In Section 3 we examine how the calculations, stimulated by the new results, have dealt with features put for the first time in clear evidence: features which seem to underlie to universal properties of inelastic collisions of elementary particles, or which stress the role of local variations of nuclear density throughout the developing of the intranuclear cascade or which hypothesize the formation of a new state of nuclear matter already at the relatively low energy reached by the experiments. In Section 4 we discuss the actual possible experimental evidences of annihilations with baryonic number greater than zero. (orig./HSI)

[en] The scientific program and the experimental setup of the DEAR (DAΦNE Exotic Atom Research) experiment at the new φ-factory DAΦNE of Laboratori Nazionali di Frascati, are described. The objective of DEAR is to perform a 1% measurement of the K_α line shift due to the strong interaction in kaonic hydrogen. A measurement will also be performed on kaonic deuterium for the first time. The aim is to investigate low-temperature pressurized gaseous target; and of a detector for soft X rays - the Charge-Coupled Device (CCD)-characterized by a good resolution and by an unprecedented background rejection capability. The DEAR experiment represents a major effort in the study of low energy KN interactions and has the potential to produce a breakthrough in the field

No abstract available