Observation of deep inelastic scattering at low x

Measurements of the scattered electron energy spectrum and the differential cross sections dσ/d log(x) and dσ/dQ2 for inclusive neutral current deep inelastic electron-proton scattering are presented. The data were obtained with the H1 detector at HERA during its first running period in which 26.7 GeV electrons collided with 820 GeV protons. The data correspond to an integrated luminosity of 1.3 nb−1 and allow the first studies of the structure of the proton at values of x down to 10−4 for Q2 > 5 GeV2.