The New Narrow "D_s" States -- A Minireview

The experimental status concerning the two new narrow states with charm-strange content is reviewed. The states have masses of 2317 and 2460 MeV, widths less than 10 MeV, isospin consistent with zero, and spin-parities consistent with being 0^+ and 1^+, respectively. Although the masses are lower than the conventional expectation, these states appear to be the j=1/2 P-wave levels of the D_s system, where j is the light quark angular momentum; there may be mixing with the j=3/2 level for the 1^+ state.Comment: 4 pages, 10 figures LaTeX; To appear in Proceedings of the International Europhysics Conference on High Energy Physics, July 17-23, 2003, Aachen. A (long file) version with some clearer figures may be found at: http://www.hep.caltech.edu/~fcp/papers/eps03.pdf This version updates version 1 with a correction to labelling of Fig. 8 (Thanks to U.Karshon for noticing this

Experimental Status of the CKM Matrix

The CKM matrix, VV, relates the quark mass and flavor bases. In the standard model, VV is unitary 3×3, and specified by four arbitrary parameters, including a phase allowing for CPCP violation. We review the experimental determination of VV, including the four parameters in the standard model context. This is an active field; the precision of experimental measurements and theoretical inputs continues to improve. The consistency of the determination with the standard model unitarity is investigated. While there remain some issues the overall agreement with standard model unitarity is good

Tensile analyses of creep in plastics using the finite element method

The deformation, stress relaxation, stress recovery, creep rupture, creep buckling, and creep ratchetting aspects of creep are discussed with the emphasis on deformation of a plastic due to a tensile load. Two problems were run using the ABAQUS Finite Element Program: an axisymmetric steel pressure vessel with elliptical end caps, and a plastic rectangular beam in tension. The pressure vessel model was used to check the ABAQUS program against the literature. A graphical comparison of the stress results showed that the program showed the proper relationships and magnitudes to confirm agreement The plastic rectangular beam problem showed an error less than 10% in total deflection and negligible error in the stress calculations

Missouri fencing laws

Cover title.Includes bibliographical references

Thermal Characterization of PMMA Thin Films on Silica Using Modulated Differential Scanning Calorimetry

The number of studies of thin polymer films has increased over recent years as technological processes incorporate the use of nanomaterials. An enhanced understanding of these films would enable us to predict bound-polymer behavior and thus improve the efficiency of processes and the quality of products. This is especially true as the thickness of the films approach molecular dimensions. The glass transition temperature of a polymer is one of the most important properties for characterization because it indicates how the polymer might perform macroscopically. when a polymer is confined, such as one the surface of a substrate, its behavior is influenced by molecular interactions between the polymer and the substrate. These interactions may affect the polymer\u27s glass transition temperature and warrant scientific investigation. This study uses modulated differential scanning calorimetric (MDSC) to examine the glass transition of poly (methyl methacrylate) adsorbed onto silica. We varied the amount of polymer adsorbed, and found that the Tg center and its breadth increased with decreased coverage. T o our knowledge this is the first reported analysis of such very thin polymer films using MDSC

Dynamics of Adsorbed Poly(Methyl Acrylate) and Poly(Methyl Methacrylate) on Silica

Deuterium NMR and modulated differential scanning calorimetry (MDSC) were used to probe the behavior of ultrathin adsorbed poly(methyl acrylate) (PMA). The spectra for the bulk methyl-labeled PMA-d3 were consistent with the motions of the polymer segments being spatially homogeneous. For the polymers adsorbed on silica, multicomponent line shapes were observed. The segmental mobility of the surface polymers increased with increased adsorbed amounts. In contrast to the behavior of the polymers in bulk, the adsorbed lower-molecular-mass PMA-d3 was less mobile than the adsorbed high-molecular-mass polymer. The presence of a polymer overlayer was sufficient to suppress the enhanced mobility of the more-mobile segments of the adsorbed (inner) polymer. MDSC studies on adsorbed poly(methyl methacrylate) showed that the glass-transition temperature of the thin polymer films increased and broadened compared to the behavior of the polymer in bulk. The presence of a motional gradient with the less-mobile segments near the solid-polymer interface and the more-mobile segments near the polymer-air interface was consistent with the experimental observations

Graduated Segmental Mobility in Polymer Layers on Silica

The behavior of thin polymer layers on oxide substrates has gotten a great deal of attention as the size of materials, and hence polymer films, has gotten smaller. Indeed, the properties of adsorbed polymers are such that they can be different from those of bulk polymers, especially when the films are very thin. A wide variety of studies have been made on adsorbed polymers and sometimes the results seem contradictory. One of the properties often measured in thin films is the apparent glasstransition temperature, Tg. In principle, many techniques are sensitive to phenomenological changes occurring around Tg and, therefore, can be compared to each other. For polymer thin films there are two surfaces (often different) to consider. For example, a thin polymer film on a solid substrate, such as silica, has a polymer-silica interface and a polymer-air interface. In principle, these two interfaces would be expected to have different properties. In addition, it is not always clear if either of these would dominate the properties measured. In this paper, we provide support for the existence of graduated segmental mobility in thin polymer films. As examples we cite the behavior observed from both deuterium NMR of poly(methyl acrylate)-d3 (PMA-d3) and modulated differential scanning calorimetry (MDSC) of poly(methyl methacrylate) (PMMA), both on silica powder. In Figure 1, we depict a surface with which the polymer has a favorable interaction. We propose that the segments at the polymer-air interface have enhanced mobility while those at the polymer-silica interfect have reduced mobility

Hadron production in e^+e^- annihilation at BABAR, and implication for the muon anomalous magnetic moment

The BABAR collaboration has an extensive program of studying hadronic cross sections in low-energy e^+e^- collisions, accessible via initial-state radiation. Our measurements allow significant improvements in the precision of the predicted value of the muon anomalous magnetic moment. These improvements are necessary for illuminating the current 3.6 sigma difference between the predicted and the experimental values. We have published results on a number of processes with two to six hadrons in the final state. We report here the results of recent studies with final states that constitute the main contribution to the hadronic cross section in the energy region between 1 and 3 GeV, as e^+e^- → K^+K^-, π^+π^-, and e^+e^- → 4 hadrons