PSP resins, new materials which can be hardened by thermal treatment for use in composite materials resistant to heat and fire

A class of easy-to-prepare heterocyclic-aromatic polymers which can be used for matrices in reinforced laminates is described. These polymers can be cured after B-staging with very little evolution of volatile materials, and they retain a low melt-viscosity which leads to low-void laminates. Resins are stable at temperatures below 150 C. Properties of composites with various reinforcements, in particular carbon-fiber unidirectional laminates, are described, and the fire behavior of PSP-glass laminates is reported

Z lineshape and forward-backward asymmetries

Preliminary but close to final results on the Z lineshape and Forward-Backward asymmetries from the four LEP experiments are presented. Combined values extracted from ALEPH. DELPHI, L3 and OPAL data recorded at energies around the Z pole are discussed.Comment: 5 pages, 6 figures, sunbmitted to the Vancouver conference, ICHEP'9

Cesium standard for satellite application

A Cesium frequency standard that was developed for satellite applications is discussed. It weighs 23 lbs. and uses 23.5 watts of power, achieves a stability of 1 x ten to the minus 13th power/100,000 seconds, and is radiation hardened. To achieve the weight and reliability requirements, both thick and thin film hybrid circuits were utilized. A crystal oscillator is used to improve short-term stability and performance on a moving platform

Comment on "Nucleon form factors and a nonpointlike diquark"

Authors of Phys. Rev. C 60, 062201 (1999) presented a calculation of the electromagnetic form factors of the nucleon using a diquark ansatz in the relativistic three-quark Faddeev equations. In this Comment it is pointed out that the calculations of these form factors stem from a three-quark bound state current that contains overcounted contributions. The corrected expression for the three-quark bound state current is derived.Comment: 6 pages, 1 figure, revtex, eps

Pfaffian-like ground state for 3-body-hard-core bosons in 1D lattices

We propose a Pfaffian-like Ansatz for the ground state of bosons subject to 3-body infinite repulsive interactions in a 1D lattice. Our Ansatz consists of the symmetrization over all possible ways of distributing the particles in two identical Tonks-Girardeau gases. We support the quality of our Ansatz with numerical calculations and propose an experimental scheme based on mixtures of bosonic atoms and molecules in 1D optical lattices in which this Pfaffian-like state could be realized. Our findings may open the way for the creation of non-abelian anyons in 1D systems

Experimental realization of plaquette resonating valence bond states with ultracold atoms in optical superlattices

The concept of valence bond resonance plays a fundamental role in the theory of the chemical bond and is believed to lie at the heart of many-body quantum physical phenomena. Here we show direct experimental evidence of a time-resolved valence bond quantum resonance with ultracold bosonic atoms in an optical lattice. By means of a superlattice structure we create a three-dimensional array of independent four-site plaquettes, which we can fully control and manipulate in parallel. Moreover, we show how small-scale plaquette resonating valence bond states with s- and d-wave symmetry can be created and characterized. We anticipate our findings to open the path towards the creation and analysis of many-body RVB states in ultracold atomic gases.Comment: 7 page, 4 figures in main text, 3 figures in appendi

Coulomb Interactions and Ferromagnetism in Pure and Doped Graphene

We study the presence of ferromagnetism in the phase diagram of the two-dimensional honeycomb lattice close to half-filling (graphene) as a function of the strength of the Coulomb interaction and doping. We show that exchange interactions between Dirac fermions can stabilize a ferromagnetic phase at low doping when the coupling is sufficiently large. In clean systems, the zero temperature phase diagram shows both first order and second order transition lines and two distinct ferromagnetic phases: one phase with only one type of carriers (either electrons or holes) and another with two types of carriers (electrons and holes). Using the coherent phase approximation (CPA) we argue that disorder further stabilizes the ferromagnetic phase.Comment: 10 pages; published versio

Recent results from NA48/2 on Ke4K_{e4} decays and interpretation in terms of ππ\pi\pi scattering lengths

Preliminary results from a new measurement of the $K_{e4}$ decay $K^{\pm} \rightarrow \pi^{+}\pi^{−}e^{\pm}\nu$ by the Na48/2 collaboration at the CERN SPS are reported. An unprecedented sample of more than 670000 $K_{e4}$ decays in both charged modes have been collected in 2003. The form factors of the hadronic current (F, G, H) and phase shift ($\delta^{0}_{0}−\delta^{1}_{1}$) of the $\pi\pi$ scattering have been measured using a model independent method and their variation with the ππ mass has been investigated. First evidence for a non zero $f_{p}$ term is reported. Thanks to a sizeable acceptance at large $\pi\pi$ mass, a low background and a very good resolution, an improved accuracy $(\pm0.006stat \pm0.005_{syst})$ can be reached when extracting the $\pi\pi$ scattering length $a^{0}_{0}$ . Using more elaborated theory inputs and another NA48/2 result from $K^{\pm} \rightarrow \pi^{0}\pi^{0}\pi^{\pm}$ decays, a consistent picture can be drawn for the scattering lengths $a^{0}_{0}$ and $a^{2}_{0}$ , in good agreement with Chiral Perturbation Theory predictions