3,700 research outputs found

    Influence of final state interaction on incoherent pion photoproduction on the deuteron in the region of the Delta-resonance

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    The influence of final state NNNN- and pi N-rescattering in incoherent pion photoproduction on the deuteron has been investigated. For the elementary photoproduction operator an effective Lagrangian model is used which describes well the elementary reaction. The interactions in the final two-body subsystems are taken in separable form. While NN-rescattering shows quite a significant effect, particularly strong for neutral pion production, pi N-rescattering is almost negligible. Inclusion of such effects leads to an improved and quite satisfactory agreement with experiment.Comment: 18 pages revtex4 including 16 postscript figure

    Spin observables for pion photoproduction on the deuteron in the Δ\Delta(1232)-resonance region

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    Spin observables for the three charge states of the pion for the pion photoproduction reaction on the deuteron, γd→πNN\gamma d\to\pi NN, with polarized photon beam and/or oriented deuteron target are predicted. For the beam-target double-spin asymmetries, it is found that only the longitudinal asymmetries T20ℓT_{20}^{\ell} and T2±2ℓT_{2\pm 2}^{\ell} do not vanish, whereas all the circular and the other longitudinal asymmetries do vanish. The sensitivity of spin observables to the model deuteron wave function is investigated. It has been found that only T21T_{21} and T22T_{22} are sensitive to the model deuteron wave function, in particular in the case of π0\pi^0-production above the Δ\Delta-region, and that other asymmetries are not.Comment: 16 pages, 8 figures, accepted for publication in J. Phys. G: Nucl. Part. Phy

    Polarization observables of the gamma d --> PiNN reaction in the Delta(1232)-resonance region

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    Polarization observables of the three charge states of the pion for the γd→πNN\gamma d\to\pi NN reaction with polarized photon beam and/or oriented deuteron target are evaluated over the whole Δ\Delta(1232)-resonance region adopting a nonrelativistic model based on time-ordered perturbation theory. Results for the π\pi-meson spectra, linear photon asymmetry, vector and tensor target asymmetries are presented. Particular attention is given, for the first time, to double polarization asymmetries for which we present results for T20ℓT_{20}^{\ell} and T2±2ℓT_{2\pm 2}^{\ell}. We found that all other double polarization asymmetries of photon and deuteron target are vanished.Comment: 17 Pages, 8 Figures, accepted for publication in Int. J. Mod. Phys.

    The Teaching of Switched Mode Power Supplies - Design, Simulation and Practical Implementation for Undergraduate and Postgraduate Students

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    © 2018 IEEE. The teaching of switched mode power supplies can be very challenging. For example, do we just teach the operation of the power supplies? Is teaching a topology enough to produce a graduate capable of designing power supplies for the highest specifications? Should we consider other details like EMI, thermal effects and packaging in the design? What will happen if we ignore them? Should these details be considered at the simulation stage, or only when it comes to manufacturing phase? This paper covers all the steps required for the design procedure of switched mode power supplies. The paper can be used in developing practical/simulation courses in power electronics for teaching the design of switched mode power supplies

    Factors influencing public attitudes toward paid online newspaper subscriptions- a field study

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    Despite the implementation of new business models in several Western media organizations, most Arab newspapers have not yet explored these models, and little is known about public attitudes towards their willingness to pay for online news. The study sought to identify factors that encourage the public to pay. It was applied to a sample of 530 newspaper consumers in the UAE, Saudi Arabia, and Oman. The study concluded that there are unfavorable trends in the public regarding their interest in following up on the news and did not show willingness for paying for online news. Most of them prefer to pay for entertainment materials. The study found that demographic variables such as age and income were important indicators of the public’s willingness to pay. Most respondents were not yet exposed to the paywall and anticipated difficulty in implementing the culture of paying for online news in Arab societies. They also expected that many print newspapers will disappear in the near future, and the idea of paying for online news was not seen favorably

    A remark on certain p

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    The object of the present paper is to prove an interesting result for certain analytic and p-valent functions in the unit disc U={z:|z|<1}

    Mean parity of single quantum excitation of some optical fields in thermal environments

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    The mean parity (the Wigner function at the origin) of excited binomial states, excited coherent states and excited thermal states in thermal channel is investigated in details. It is found that the single-photon excited binomial state and the single-photon excited coherent state exhibit certain similarity in the aspect of their mean parity in the thermal channel. We show the negative mean parity can be regarded as an indicator of nonclassicality of single-photon excitation of optical fields with a little coherence, especially for the single-photon excited thermal states.Comment: 4 pages, 4 figures, RevTex4; PACS numbers: 42.50.Dv, 03.65.Yz, 05.40.Ca; Three typo errors have been correcte
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