364 articles – 2937 Notices  [english version]
 HAL : in2p3-00003649, version 1
 arXiv : hep-ex/9812023
 Nuclear Physics B 545 (1999) 21-44
 Measurement of d$^\star$ meson cross-sections at Hera and determination of the gluon density in the proton using NLO QCD
 H1 Collaboration(s)
 (1999)
 With the H1 detector at the ep collider HERA, D* meson production cross sections have been measured in deep inelastic scattering with four-momentum transfers Q^2>2 GeV2 and in photoproduction at energies around W(gamma p)~ 88 GeV and 194 GeV. Next-to-Leading Order QCD calculations are found to describe the differential cross sections within theoretical and experimental uncertainties. Using these calculations, the NLO gluon momentum distribution in the proton, x_g g(x_g), has been extracted in the momentum fraction range 7.5x10^{-4}< x_g <4x10^{-2} at average scales mu^2 =25 to 50 GeV2. The gluon momentum fraction x_g has been obtained from the measured kinematics of the scattered electron and the D* meson in the final state. The results compare well with the gluon distribution obtained from the analysis of scaling violations of the proton structure function F_2.
 Thème(s) : Physique/Physique des Hautes Energies - Expérience
 Lien vers le texte intégral : http://fr.arXiv.org/abs/hep-ex/9812023
 in2p3-00003649, version 1 http://hal.in2p3.fr/in2p3-00003649 oai:hal.in2p3.fr:in2p3-00003649 Contributeur : Magali Damoiseaux <> Soumis le : Mercredi 26 Mai 1999, 17:11:15 Dernière modification le : Mercredi 26 Mai 1999, 17:11:15