Three body resonances in two meson-one baryon systems

We report four $\Sigma$'s and three $\Lambda$'s, in the 1500 - 1800 MeV region, as two meson - one baryon S-wave $(1/2)^+$ resonances. We solve Faddeev equations in the coupled channel approach. The invariant mass of one of the meson-baryon pairs and that of the three particles have been varied and peaks in the squared three body $T$-matrix have been found very close to the existing $S$ = -1, $J^P= 1/2^+$ low lying baryon resonances. The input two-body $t$-matrices for meson-meson and meson-baryon interaction have been calculated by solving the Bethe-Salpeter equation with the potentials obtained in the chiral unitary approach.Comment: corrected version, new channels evaluated, new references adde

Dynamics and Shape of Brightest Cluster Galaxies

We identified Brightest Cluster Members (BCM) on DSS images of 1083 Abell clusters, derived their individual and host cluster redshifts from literature and determined the BCM ellipticity. Half the BCMs move at a speed higher than 37 % of the cluster velocity dispersion sigma_{cl}, suggesting that most BCMs are part of substructures falling into the main cluster. Both, the BCM's velocity offset in units of sigma_{cl}, and BCM ellipticity, weakly decrease with cluster richness.Comment: 2 pages, 2 figures, Proc. ESO Workshop "Groups of galaxies in the nearby Universe", Santiago, Chile, 5-9 Dec. 2005, ESO Astrophysics Symposia, eds. I. Saviane, V. Ivanov & J. Borissova, Springer-Verla

Risk Aversion over Incomes and Risk Aversion over Commodities

This note determines the precise connection between an agent's attitude towards income risks and his attitude over risks in the underlying consumption space. Our results follow a general mathematical theory connecting the curvature properties of an objective function with the ray-curvature properties of its dual.risk aversion, concavity, duality

Prediction of force coefficients for labyrinth seals

The development of a linear model for the prediction of labyrinth seal forces and on its comparison to available stiffness data is presented. A discussion of the relevance of fluid damping forces and the preliminary stages of a program to obtain data on these forces are examined. Fluid-dynamic forces arising from nonuniform pressure patterns in labyrinth seal glands are known to be potentially destablizing in high power turbomachinery. A well documented case in point is that of the space Shuttle Main Engine turbopumps. Seal forces are also an important factor for the stability of shrouded turbines, acting in that case in conjunction with the effects of blade-tip clearance variations

Dirac Quantization of Two-Dimensional Dilaton Gravity Minimally Coupled to N Massless Scalar Fields

It is shown that the Callan-Giddings-Harvey-Strominger theory on the cylinder can be consistently quantized (using Dirac's approach) without imposing any constraints on the sign of the gravitational coupling constant or the sign (or value) of the cosmological constant. The quantum constraints in terms of the original geometrical variables are also derived

Study of the D∗ρD^*\rho system using QCD sum rules

In this talk I present a study of the $D^* \rho$ system made by using the method of QCD sum rules. Considering isospin and spin projectors, we investigate the different configurations and obtain three $D^*$ mesons with isospin $I=1/2$, spin $S=0$, $1$, $2$ and with masses $2500\pm 67$ MeV, $2523\pm60$ MeV, and $2439\pm119$ MeV, respectively. The last state can be related to $D^*_2(2460)$ (spin 2) listed by the Particle Data Group, while one of the first two might be associated with $D^*(2640)$, whose spin-parity is unknown. In the case of $I=3/2$ we also find evidences of three states with spin 0, 1 and 2, respectively, with masses $2467\pm82$ MeV, $2420\pm128$ MeV, and $2550\pm56$ MeV.Comment: Contribution to the proceedings of the XXXVI Reuni\~ao de Trabalho sobre F\'isica Nuclear no Brasil, Maresias, S\~ao Paulo, Brazi