79 research outputs found

    Electromagnetic form factors of the baryon octet in the perturbative chiral quark model

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    We apply the perturbative chiral quark model at one loop to analyze the electromagnetic form factors of the baryon octet. The analytic expressions for baryon form factors, which are given in terms of fundamental parameters of low-energy pion-nucleon physics (weak pion decay constant, axial nucleon coupling, strong pion-nucleon form factor), and the numerical results for baryon magnetic moments, charge and magnetic radii are presented. Our results are in good agreement with experimental data.Comment: 15 pages, 6 figures, to be published in Eur. Phys. J.

    The statistical parton distributions: status and prospects

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    New experimental results on polarized structure functions, cross sections for e±pe^{\pm}p neutral and charge current reactions and ν\nu (νˉ\bar{\nu}) charge current on isoscalar targets are compared with predictions using the statistical parton distributions, which were previously determined. New data on cross sections for Drell-Yan processes, single jet in ppˉp\bar{p} collisions and inclusive π0\pi^0 production in pppp collisions are also compared with predictions from this theoretical approach. The good agreement which we find with all these tests against experiment, strenghtens our opinion on the relevance of the role of quantum statistics for parton distributions. We will also discuss the prospects of this physical framework.Comment: 34 pages, 23 figures, references and figures adde

    Reconclining phi radiative decays with other data for a0(980), fo(980), pi-pi -> KK and pi-pi -> eta-eta

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    Data for phi -> gamma (eta-pizero) are analysed using the KK loop model and compared with parameters of a0(980) derived from Crystal Barrel data. The eta-pi mass spectrum agrees closely and the absolute normalisation lies just within errors. However, BES parameters for fo(980) predict a normalisation for phi -> gamma (pizero-pizero) at least a factor 2 lower than is observed. This discrepancy may be eliminated by including constructive interference between fo(980) and sigma. The magnitude required for sigma -> KK is consistent with data on pi-pi -> KK. A dispersion relation analysis by Buttiker, Descotes-Genon and Moussallam of pi-pi -> KK leads to a similar conclusion. Data on pi-pi -> eta-eta also require decays of sigma to eta-eta. Four sets of pi-pi -> KK data all require a small but definite fo(1370) signal.Comment: 21 pages, 11 figures, Small rearrangement of reference

    Probing the QCD equation of state with thermal photons in nucleus-nucleus collisions at RHIC

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    Thermal photon production at mid-rapidity in Au+Au reactions at sNN\sqrt{s_{NN}} = 200 GeV is studied in the framework of a 2D+1 hydrodynamical model that describes efficiently the bulk identified hadron spectra at RHIC. The combined thermal plus NLO pQCD photon spectrum is in good agreement with the yields measured by the PHENIX experiment for all Au+Au centralities. Within our model, we demonstrate that the correlation of the thermal photon slopes with the charged hadron multiplicity in each centrality bin provides direct empirical information on the underlying degrees of freedom and on the equation of state, s(T)/T3s(T)/T^3, of the strongly interacting matter.Comment: Version to appear in EPJ-C (extended discussion and refs. and a few corrections

    Pensions to Indian fighters

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    25-2Select Committee on Extending the Provisions of the Pension Law of 1832 to Troops Employed Against the Indians.Report on Pensions to Indian Fighters. [333] Recommends extension of laws to the period 1783 to 1795.1838-1

    angustifolia

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    Populus angustifolia E. Jamesnarrow-leaved cottonwood;narrow-leaved balsam poplar;willow cottonwood;mountain cottonwoodpeuplier Ă  feuilles Ă©troitesN. side of Drywood River, E. side of bridgetreed terrace4000 fee

    carthusiana

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    Dryopteris carthusiana (Vill.) H.P.Fuchsdryoptère spinuleuseSpinulose wood fernMill CreekT. ChisholmN. of Gladstone Mt.; clearing along trail surrounded by Picea glauca1490 mDryopteris, Etheryium, Urtica dioica, Rubus parviflorus, Mitella sp., Actaea rubr
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