Results 1 - 10 of 5715
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[en] Here, we compare the methods of amplitude reconstruction, for a complete experiment and a truncated partial-wave analysis, applied to the photoproduction of pseudoscalar mesons. The approach is pedagogical, showing in detail how the amplitude reconstruction (observables measured at a single energy and angle) is related to a truncated partial-wave analysis (observables measured at a single energy and a number of angles).
[en] In this course, scattering theory and chemical reactions are presented including scattering of one particle by a potential, n-particle systems, colinear triatomic molecules and the study of reactive scattering for 3-dimensional triatomic systems. (A.C.A.S.)
[pt]Neste curso, apresenta-se a teoria de espalhamento e reacores quimicas incluindo-se o espalhamento de uma particula por um potencial, sistemas de n-particulas, moleculas triatomicas colineares e o estudo do espalhamento reativo de sistemas triatomicos em 3 dimensoes. (A.C.A.S.)
[en] A measurement of the double-polarization observable E for the reaction γp→πp is reported. The data were taken with the CBELSA/TAPS experiment at the ELSA facility in Bonn using the Bonn frozen-spin butanol (CHOH) target, which provided longitudinally-polarized protons. Circularly-polarized photons were produced via bremsstrahlung of longitudinally-polarized electrons. The data cover the photon energy range from E=600 to 2310 MeV and nearly the complete angular range. The results are compared to and have been included in recent partial wave analyses.
[en] We show that two almost degenerate poles near the πΔ threshold and the next higher mass pole in the P11 partial wave of πN scattering evolve from a single bare state through its coupling with πN, ηN, and ππN reaction channels. This finding provides new information on understanding the dynamical origins of the Roper N*(1440) and N*(1710) resonances listed by Particle Data Group. Our results for the resonance poles in other πN partial waves are also presented.
[en] A new generation of complete experiments in pseudoscalar meson photo-production is being pursued at several laboratories. While new data are emerging, there is some confusion regarding definitions of asymmetries and the conventions used in partial wave analyses (PWA). We present expressions for constructing asymmetries as coordinate-system independent ratios of cross sections, along with the names used for these ratios by different PWA groups.
[en] The formalism of Barrelet zeros is discussed. Spinless scattering is described to introduce the idea, then the more usual case of 0-1/2+ → 0-1/2+ scattering. The zeros are regarded here only as a means to an end, viz the partial waves. The extraction of these is given in detail, and ambiguities are discussed at length. (author)
[en] We present a selection of recent results on light hadron spectroscopy from the BESIII collaboration. The topics include the full partial wave analysis on J/ψ radiative decays, including J/ψ → γηη and γωϕ. Besides, we also cover the topics about the resonance Y(2175) and η(1405). (author)
[en] Analyticity constitutes a rigid constraint on hadron scattering amplitudes. This property is used to relate models in different energy regimes. Using meson photoproduction as a benchmark, we show how to test contemporary low energy models directly against high energy data. This method pinpoints deficiencies of the models and treads a path to further improvement. In conclusion, the implementation of this technique enables one to produce more stable and reliable partial waves for future use in hadron spectroscopy and new physics searches.