Measurement of the neutral current DIS cross section at H1

Abstract

New preliminary measurements of the inclusive neutral current ep scattering cross sections from the H1 experiment at HERA are presented.The inclusive ep scattering cross ection is measured in the region of low negative four-momentum transfer squared, 0.2 ≤ Q2 ≤ 12 GeV2, and low Bjorken x, 5·10-6 ≤ x ≤ 0.02. The result is based on two data sets collected in dedicated runs at beam energies of 27.5 GeV for positrons and 920 GeV for protons and covers the transition region from quasi-real photoproduction to deep inelastic scattering. A combination with data used in results previously published by H1 leads to an accuracy of a few percent on the resulting cross section measurement. Measurements of the e±p inclusive cross sections are presented in the region of high inelasticity y > 0.6 at low (8 ≤ Q2 ≤ 50 GeV2) and medium (65 ≤ Q2 ≤ 800 GeV2) values of Q2. At high values of inelasticity the cross section is sensitive to the longitudinal structure function F land thus provides additional constraints on DGLAP evolution. These results are based on data collected during the years 2003-2007 (HERA-II) which correspond to an integrated luminosity of 315 pb-1. About equal luminosities obtained for the e+p and e−p samples allow for a high precision control of background processes.