185,905 research outputs found

    Baryon Electromagnetic Form Factors at BESIII

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    The electromagnetic form factors are fundamental observables that parametrise the electric and magnetic structure of hadrons and provide a key to the strong interaction. The Beijing Spectrometer (BESIII) is located at the Beijng Electron Positron Collider (BEPCII), a symmetric e+ee^+e^- collider running at center-of-mass energies between 2.0 and 4.6 GeV. This wide energy range allows the measurement of electromagnetic form factors both from direct e+ee^+e^- annihilation and from initial-state radiation processes. Based on 157 pb1157~\mathrm{pb}^{-1} of data collected at center-of-mass energies between 2.23 and 3.67 GeV, BESIII published results on the channel e+eppˉe^+e^-\rightarrow p\bar{p}. More recently, preliminary results from the analysis of the initial-state radiation process e+eppˉγe^+e^- \rightarrow p\bar{p}\gamma based on 7.41 fb1\mathrm{fb}^{-1} of data have also been released. Besides nucleons, all hyperons in the SU(3) spin 1/2 octet and spin 3/2 decuplet are energetically accessible at BESIII. Preliminary results from the e+eΛΛˉe^+e^-\rightarrow \Lambda\bar{\Lambda} channel and the e+eΛcΛˉce^+e^- \rightarrow \Lambda_c \bar{\Lambda}_c channel from the charmed sector are already available. Furthermore, a world-leading data sample for precision measurements of baryon form factors was collected in 2015. This data will enable the measurement of baryon electromagnetic form factors with unprecedented accuracy.Comment: 9 pages, 11 figures. Proceedings from Bormio 2017 conference, submitted to Po

    Topological defects in 1D elastic waves

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    It has been recently shown theoretically that a topological defect in a 1D periodic potential may give rise to two localized states within the energy gaps. In this work we present an experimental realization of this effect for the case of torsional waves in elastic rods. We also show numerically that three, or even more, localized states can be present if the parameters characterizing the topological defect are suitably varied.Comment: 3 pages, 4 figures, accepted in Physica

    Model-driven design of geo-information services

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    This thesis presents a method for the development of distributed geo-information systems. The method is organised around the design principles of modularity, reuse and replaceability. The method enables the modelling of both behavioural and informational aspects of geo-information systems in an integrated way. This thesis introduces the concept the Geo-information Service Infrastructure (GSI)

    Simplicial ideals, 2-linear ideals and arithmetical rank

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    In the first part of this paper we study scrollers and linearly joined varieties. A particular class of varieties, of important interest in classical Geometry are Cohen--Macaulay varieties of minimal degree. They appear naturally studying the fiber cone of of a codimension two toric ideals. Let ISI\subset S be an ideal defining a linearly joined arrangement of varieties: - We compute the depth, and the cohomological dimension. is the connectedness dimension. - We characterize sets of generators of II, and give an effective algorithm to find equations, as an application we compute arithmetical rank. in the case if II defines a union of linear spaces, (ara =projective dimension), in particular this applies to any square free monomial ideal having a 22- linear resolution. - In the case where VV is a union of linear spaces, the ideal II, can be characterized by a tableau, which is an extension of a Ferrer (or Young) tableau. - We introduce a new class of ideals called simplicial ideals, ideals defining linearly-joined varieties are a particular case of simplicial ideals.Comment: 31 pages, 5 figure

    Non-integrability of geodesic flow on certain algebraic surfaces

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    This paper addresses an open problem recently posed by V. Kozlov: a rigorous proof of the non-integrability of the geodesic flow on the cubic surface xyz=1x y z=1. We prove this is the case using the Morales-Ramis theorem and Kovacic algorithm. We also consider some consequences and extensions of this result.Comment: Accepted in Physics Letters