Non polynomial conservation law densities generated by the symmetry operators in some hydrodynamical models

New extra series of conserved densities for the polytropic gas model and nonlinear elasticity equation are obtained without any references to the recursion operator or to the Lax operator formalism. Our method based on the utilization of the symmetry operators and allows us to obtain the densities of arbitrary homogenuity dimensions. The nonpolynomial densities with logarithmics behaviour are presented as an example. The special attention is paid for the singular case $(\gamma=1)$ for which we found new non homogenious solutions expressed in terms of the elementary functions.Comment: 11 pages, 1 figur

Classification of integrable hydrodynamic chains and generating functions of conservation laws

New approach to classification of integrable hydrodynamic chains is established. Generating functions of conservation laws are classified by the method of hydrodynamic reductions. N parametric family of explicit hydrodynamic reductions allows to reconstruct corresponding hydrodynamic chains. Plenty new hydrodynamic chains are found

Changes in the annihilation delay time distribution of stopped antiprotons in helium gas, due to contaminants. II

A different type of analysis was performed to study the effect of contaminants on the temporal distribution of delayed annihilations of antiprotons stopped in helium gas, with respect to some first results published in Ableevet. al. (Nuovo Cimento A,107 (1994) 1325). A more objective criterion was established to single out aslow part in the total delayed component, in order to deduce from this, for each case, the mean value of the product (vσ − − ) c,l of the quenching cross-section and the mean velocity of contaminant molecules, and the fraction of the slow componentη c, l . The fractionη c, l was found to be amazingly stable for each impurity, independent of the concentration: around 79% of the total delayed component for all the atomic impurities (Ar, Ne, Xe) and 64% for the molecular ones (H2, N2

Observation of the Doubly Strange b Baryon Ωb−

We report the observation of the doubly strange b baryon Omega(-)(b) in the decay channel Omega(-)(b) -> J/psi Omega(-), with J/psi -> mu(+)mu(-) and Omega(-) -> Lambda K- -> (p pi(-))K-, in p (p) over bar collisions at root s = 1.96 TeV. Using approximately 1.3 fb(-1) of data collected with the D0 detector at the Fermilab Tevatron Collider, we observe 17.8 +/- 4.9(stat) +/- 0.8(syst) Omega(-)(b) signal events at a mass of 6.165 +/- 0.010(stat) +/- 0.013(syst) GeV. The significance of the observed signal is 5.4 sigma, corresponding to a probability of 6.7 x 10(-8) of it arising from a background fluctuation.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP