Robert A. Eisenstein

Study of the reaction pp→ΛΛ near threshold

Abstract Results are presented from a study of the reaction p p→ Λ Λ near threshold. Over 3000 events recorded at s values 14.6 and 25.5 MeV above the Λ Λ threshold (2231.2 MeV) have been analysed. Results for the production cross section, differential cross section, and the Λ and Λ polarization are given at both energies and are compared with recent theoretical calculations of this process.

Summary of sessions on hypernuclei physics

The Conference sessions on hypernuclear physics are summarized and reviewed. In all, six parallel sessions were devoted to this topic, ranging in subject matter from the elementary K‐nucleon system to the hypernuclear many‐body problem. The present status of the field was discussed, as were some of the future prospects. There is great promise for learning much new information about the many‐body physics of strong interactions, specifically, nuclear systems in which lambda or sigma hyperon ‘‘impurities’’ have been implanted. However, presently it is clear that if the field is to achieve dramatic new succeses, presently available facilities must be improved significantly.

The Jetset experiment at lear

The Jetset experiment (PS 202) at LEAR will search for gluonic hadrons and other exotics in the interaction of in‐flight antiprotons with protons at rest. The mass range to be covered extends from 1.96 to 2.43 GeV. Our experiment uses a molecular hydrogen cluster jet target which is inserted in the LEAR ring and is surrounded by a general‐purpose detetor of advanced design. In ‘‘Phase I’’ the detector has been constructed to provide selection at the trigger level of four kaon events, allowing a search for resonances in the OZI‐forbidden, gluon‐rich reaction pp→φφ→4K. The combination of LEAR with our detector is unique in that it allows scanning over a large momentum range with excellent momentum resolution, implying corresponding excellent mass resolution. The physics interest in this process is outlined briefly, and the design of the detector elments is described in some detail. A brief discussion of possible upgrade paths (‘‘Phase II’’) for the detecor is given at the end.

Threshold Studies at LEAR

Various thresholds for the production of stable particles can be reached with beams from LEAR (Table 1). At thresholds the new particles appear in the centre of mass (cm.) system with vanishing relative energy. For a long time they stay close to each other, so that there will be strong final-state interaction (f.s.i.). If this f.s.i. can be sorted out then we can get information about low-energy interactions of many interesting particle combinations which are not available so far1. A systematic comparison could be valuable for a better understanding of low-energy quark dynamics.