摘要:

The production of antihyperon‐hyperon pairs out of the antiproton‐proton collison has been studied by the PS185 collaboration using the Low Energy Antiproton Ring (LEAR) at CERN. The emphasis of the studies is to investigate the production threshold region. Results obtained for the reactions p¯p→&Lgr;¯&Lgr; and p¯p→&Lgr;¯&Sgr;°=c.c. are presented and discussed. Total‐ and differential cross sections were measured, polarizations, spin correlations and singlet fractions were extracted at a variety of incident antiproton momenta.The investigations of the collaboration concentrated on the &Lgr;¯&Lgr;‐final channel. Data on p¯p→&Lgr;¯&Lgr; are a vailable for a rather wide energy range. A few results on the &Lgr;&Sgr; channel were analyzed as well as some events for the p¯p→&Sgr;¯+&Sgr;+reaction. Further investigations on the charged sigma final hyperon‐antihyperon pairs are planned and in progress.

ISSN:0094-243X    

DOI:10.1063/1.40343

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

The status of the results and the analyses of associated strangeness production in Nucleon‐Nucleon collisions at Saturne (LNS, Saclay France) is presented. Plans for a new large accepteance spectrometer which are working out for spin observable measurements are exposed.

ISSN:0094-243X    

DOI:10.1063/1.40344

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

Hypernuclei have been studied for the last 35 years using several techniques. Since 1970, theAZ (K−, &pgr;−)A&Lgr;Z strangeness‐exchange reaction has been used at CERN, BNL and KEK to produce hypernuclei and study their spectroscopic properties. These studies also include experiments where decay gamma rays and hypernuclear weak decay products are detected in coincidence with hypernuclear production. Recent experiments at BNL and KeK have proven the utility of theAZ (&pgr;+, K+)A&Lgr;Z reaction to study hypernuclear spectroscopy. Although I have no hope of covering this field in much detail, I write this paper as an introduction to the subject and highlight some of the recent experimental developments.

ISSN:0094-243X    

DOI:10.1063/1.40345

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

A brief overview of the experimental status of eletro‐ and photo‐production of hyperons from a proton target is given; with some discussion of likely directions for future work.

ISSN:0094-243X    

DOI:10.1063/1.40346

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

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 p¯p→&fgr;&fgr;→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.

ISSN:0094-243X    

DOI:10.1063/1.40347

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

At present the cooler synchrotron COSY, a synchrotron and storage ring for medium energy physics is bult at Ju¨lich. The cooler ring will deliver protons and light ions in the momentum range of 275 to 3300 MeV/c. To increase the phase space density of the circulating protons electron and stochastic cooling will be used. The cooled beams will be used for experiments with interal and after slow extraction with external targets.The facility consists of different ion sources, the cyclotron JULIC as injector, the 100 m long injection beam line, the ring with a cicumference of 184 m and the extraction beam lines to the external areas. The start of the users operations is provided to be in autumn 1992. A short overview of the machine, beam parameters and the status is given. Special emphasis is given to the polarized beam facility.

ISSN:0094-243X    

DOI:10.1063/1.40349

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

A simple discussion of electron cooling theory, with emphasis on relativistic scaling relations, is given. This discusion is used to predict the behaviovr of electron cooled beams, subjected also to an internal target and to intrabeam scattering. Technical considerations relating to the alignment and the confinement of electron beams for cooling indicate that the longitudinal magnetic field will be abandoned in favour of focusing by discrete lenses at electron energies above about 1 MeV. The experiments on acceleration, transport, and collection of prototype electron beams made at Novosibirsk and Wisconsin are discussed. It is concluded that intermediate energy electron cooling is within the capability of present technology, and although its most important application may be for improving the luminosity of colliders, nuclear and particle physics applications requiring high energy, spatial, or time resolution also may benefit.

ISSN:0094-243X    

DOI:10.1063/1.40350

出版商:AIP    

年代:1991

数据来源: AIP

摘要:

It is worth stopping to ask ourselves why we are here; why hesitate on the threshold of particle physics before plunging in. In fact there is an excellent reason, because on the edge you can take your bearings and establish your reference system, but once you have jumped into the morass of the strong interactions, you can loss your sense of direction very easily.

ISSN:0094-243X    

DOI:10.1063/1.40351

出版商:AIP    

年代:1991

数据来源: AIP