Partial-wave analysis of the eta pi+ pi- system produced in the reaction pi-p --> eta pi+ pi- n at 18 GeV/c

A partial-wave analysis of 9082 eta pi+ pi- n events produced in the reaction pi- p --> eta pi+ pi- n at 18.3 GeV/c has been carried out using data from experiment 852 at Brookhaven National Laboratory. The data are dominated by J^{PC} = 0^{-+} partial waves consistent with observation of the eta(1295) and the eta(1440). The mass and width of the eta(1295) were determined to be 1282 +- 5 MeV and 66 +- 13 Mev respectively while the eta(1440) was observed with a mass of 1404 +- 6 MeV and width of 80 +- 21 MeV. Other partial waves of importance include the 1++ and the 1+- waves. Results of the partial wave analysis are combined with results of other experiments to estimate f1(1285) branching fractions. These values are considerably different from current values determined without the aid of amplitude analyses.Comment: 22 pages, 8 figure

Constante diélectrique du gaz chlorhydrique en fonction de la pression

Description of a high-pressure cell and a condenser to measure the dielectric constant of compressed gases. Study of nitrogen up to 150 atmospheres and comparison with Michels' measurements. First results on hydrogen chloride at temperatures 25 °C and 50 °C up to 40 atmospheres.Description d'une cuve et d'un condensateur destinés à la mesure de la constante diélectrique de gaz comprimés. Étude de l'azote jusqu'à 150 atmosphères et comparaison avec les mesures de Michels. Premiers résultats pour le gaz chlorhydrique aux températures 25 °C et 50 °C jusqu'à 40 atmosphères

Constantes diélectriques et indices de réfraction des gaz en fonction de la pression

Describes expérimental and theoretical techniques used in the study of the effects of pressure on dielectric constants and refractive indexes varying with the pressure. Variation of the Clausius-Mosotti and Lorentz-Lorenz functions with pressure. We distinguish between polar and non-polar molecules. For most gases that have been studied, both functions show an increase at low density and a decrease at high density. The various results are interpreted by statistical theories, wich we review.Exposé des techniques expérimentales et théoriques concernant l'étude des constantes diélectriques et des indices de réfraction en fonction de la pression. Variation des fonctions de Clausius-Mosotti et de Lorentz-Lorenz avec la pression. On distinguera les molécules polaires et non polaires. Pour la plupart des gaz étudiés les deux fonctions présentent une croissance à basse densité et une décroissance à forte densité. Les divers résultats sont interprétés par des théories statistiques que nous passerons en revue

ATLAS Event Filter Tests on the ASGARD cluster at ETH Zurich

We present here results from a series of tests of the supervision system of the PC-based ATLAS Event Filter prototype performed at the asgard Cluster at ETH Z rich. Preliminary conclusions are also drawn on the operation of the name server used in the farm. Further tests will be necessary in order to fully understand effects which have not been seen on smaller configurations

Supervision in the PC based prototype for the ATLAS event filter

A prototype of the ATLAS event filter based on commodity PCs linked by a Fast Ethernet switch has been developed in Marseille. The present contribution focus on the supervision aspects of the prototype based on Java and Java mobile agents technology. (5 refs)