Eur. Phys. J. C 21, 33-61 (2001)
Deep-inelastic inclusive ep scattering at low x and a determination ofThe H1 Collaboration C. Adloff and et al.
Fachbereich Physik, Bergische Universität Gesamthochschule Wuppertal, Wuppertal, Germany
(Received: 21 December 2000 / Revised version: 10 May 2001 / Published online: 6 July 2001 -© Springer-Verlag / Società Italiana di Fisica 2001 )
A precise measurement of the inclusive deep-inelastic e+ p scattering cross section is reported in the kinematic range GeV2GeV2and . The data were recorded with the H1 detector at HERA in 1996 and 1997, and correspond to an integrated luminosity of 20 pb-1. The double differential cross section, from which the proton structure function F2(x,Q2)and the longitudinal structure function FL(x,Q2)are extracted, is measured with typically 1% statistical and 3% systematic uncertainties. The measured derivative is observed to rise continuously towards small x for fixed Q2. The cross section data are combined with published H1 measurements at high Q2 for a next-to-leading order DGLAP QCD analysis. The H1 data determine the gluon momentum distribution in the range to within an experimental accuracy of about 3% for Q2 =20 GeV2GeV2. A fit of the H1 measurements and the data of the BCDMS collaboration allows the strong coupling constant and the gluon distribution to be simultaneously determined. A value of is obtained in NLO, with an additional theoretical uncertainty of about , mainly due to the uncertainty of the renormalisation scale.
© Società Italiana di Fisica, Springer-Verlag 2001