Neutral current interactions in ep scattering with longitudinally po larised leptons at H1

The inclusive deep inelastic cross sections are measured for the neutral current process, $e^{\pm}p \rightarrow e^{\pm} X$, in interactions with longitudinally polarised lepton beams of HERA II at large negative four-momentum transfer squared $Q^2 \geq 150$ GeV$^2$. The polarisation asymmetries of the neutral current $e^-p$ and $e^+p$ cross sections are presented. The cross sections are combined with previously published data from H1 to obtain the most precise unpolarised measurements. The lepton charge asymmetry of the unpolarised cross sections is used to extract the structure function $xF_3^{\gamma Z}$. The measurements are found to be in agreement with the Standard Model expectations