The high-intensity hyperon beam at CERN

A high-intensity hyperon beam was constructed at CERN to deliver Sigma- to experiment WA89 at the Omega facility and operated from 1989 to 1994. The setup allowed rapid changeover between hyperon and conventional hadron beam configurations. The beam provided a Sigma-flux of 1.4 x 10^5 per burst at mean momenta between 330 and 345 Gev/c, produced by about 3 x 10^10 protons of 450 GeV/c . At the experiment target the beam had a Sigma-/pi- ratio close to 0.4 and a size of 1.6 x 3.7 cm^2. The beam particle trajectories and their momenta were measured with a scintillating fibre hodoscope in the beam channel and a silicon microstrip detector at the exit of the channel. A fast transition radiation detector was used to identify the pion component of the beam.Comment: 20 pages, 13 figures. Submitted to Nucl. Instr. Meth.

Extremely Low Loss Phonon-Trapping Cryogenic Acoustic Cavities for Future Physical Experiments

Low loss Bulk Acoustic Wave devices are considered from the point of view of the solid state approach as phonon-confining cavities. We demonstrate effective design of such acoustic cavities with phonon-trapping techniques exhibiting extremely high quality factors for trapped longitudinally-polarized phonons of various wavelengths. Quality factors of observed modes exceed 1 billion, with a maximum $Q$-factor of 8 billion and $Q\times f$ product of $1.6\cdot10^{18}$ at liquid helium temperatures. Such high sensitivities allow analysis of intrinsic material losses in resonant phonon systems. Various mechanisms of phonon losses are discussed and estimated

SU(3) Breaking in Hyperon Beta Decays: a Prediction for Xi^0 -> Sigma^+ e nu-bar

On the basis of a previous analysis of hyperon semi-leptonic decay data, a prediction is presented for g_1/f_1 in the Xi^0 -> Sigma^+ e nu-bar beta-decay. The analysis takes into account SU(3) breaking in this sector via the inclusion of mass-driven corrections. A rather precise measurement of the above channel by the KTeV experiment at Fermilab will shortly be available. Since the dependence on the SU(3) parameters, F and D, is identical to that of the neutron beta-decay, such a measurement will provide a rather stringent test of SU(3) and the models used to describe its violation in these decays. The prediction given here for the above decay is g_1/f_1=1.17, which leads to a rate of 0.80 x 10^6 s^-1 and thus a branching fraction of 2.3 x 10^-4.Comment: LaTeX, 7 pages, uses acromake, cite and topcapt packages. Non-printing extended ascii characters replaced plus minor correction

Identification of sixteen grapevine rootstocks by RFLP and RFLP analysis of nuclear DNA extracted from the wood

Sixteen rootstocks of the Vitis genus have been identified by the RFLP analysis methodology with the restriction enzyme HinfI. Uniques or moderately repeated DNA sequences of the nuclear genome of the Chardonnay V. vinifera variety were used as probes. RFLP analysis of 5 clones of SO 4 (V. berlandieri x V. riparia) and of 3 clones of 41 B Mgt (V. berlandieri x V. vinifera) with 4 probes and HinfI did not lead to any polymorphism. This is not surprising because of the vegetative origin of the clones. A simple method of nuclear DNA extraction of wood is described for the grapevine. We propose now the RFLP analysis methodology to complement or to replace in certain cases the ampelographical methods of identification of the rootstocks. The extension of this application to the V. vinifera varieties is considered.Identification de 16 porte-greffes de vigne par analyse RFLP, et analyse RFLP d'ADN nucléaire extrait à partir du boisNous avons identifié 16 porte-greffes du genre Vitis par la méthodologie d'analyse du polymorphisme de longueur des fragments de restriction (RFLP) de l'ADN avec l'enzyme de restriction HinfI. Pour cela, nous avons utilisé comme sondes des fragments d'ADN uniques ou peu répétés du génome de la variete Chardonnay de Vitis vinifera. L'analyse RFLP de cinq clones de SO 4 (V. berlandieri x V. riparia) et de trois clones de 41 B Mgt (V. berlandieri x V. vinifera) avec quatre sondes RFLP et l'enzyme HinfI n'a pas permis de différencier les clones d'un même hybride, dont les genomes sont extrêmement proches puisqu'ils sont obtenus de façon végétative. Nous présentons aussi une méthode simple d'extraction d'ADN nucléaire à partir du bois de vigne. Les analyses RFLP de cet ADN ont donné des résultats identiques à ceux obtenus avec l'ADN des feuilles. Nous sommes maintenant en mesure de proposer que la méthodologie d'analyse RFLP complète ou remplace dans certains cas les méthodes ampélographiques d'identification des portegreffes du genre Vitis. L'élargissement de cette application est envisagé pour les varietes de Vitis vinifera

Collaboration in a multi-user game: impacts of an awareness tool on mutual modeling

This paper presents an experimental research that focuses on collaboration in a multi-player game. The aim of the project is to study the cognitive impacts of awareness tools, i.e., artifacts that allow users of a collaborative system to be aware of what is going on in the joint virtual environment. The focus is on finding an effect on performance as well as on the representation an individual builds of what his partner knows, plans and intends to do (i.e., mutual modeling). We find that using awareness tools has a significant effect by improving task performance. However, the players who were provided with this tool did not show any improvement of their mutual modeling. Further analysis on contrasted groups revealed that there was an effect of the awareness tool on mutual modeling for players who spent a large amount of time using the too

Experiments to Find or Exclude a Long-Lived, Light Gluino

Gluinos in the mass range ~1 1/2 - 3 1/2 GeV are absolutely excluded. Lighter gluinos are allowed, except for certain ranges of lifetime. Only small parts of the mass-lifetime parameter space are excluded for larger masses unless the lifetime is shorter than ~ 2 10^{-11} (m_{gluino}/ GeV) sec. Refined mass and lifetime estimates for R-hadrons are given, present direct and indirect experimental constraints are reviewed, and experiments to find or definitively exclude these possibilities are suggested.Comment: 27 pp, latex with 1 uufiled figure, RU-94-35. New version amplifies discussion of some points and corresponds to version for Phys. Rev.