Inclusive single diffractive dissociation (pp->pX) is studied using data collected by the
ATLAS experiment at the LHC. The intact proton is reconstructed and measured in the
ALFA forward spectrometer, while charged particles from the dissociative system (X)
are reconstructed and measured using the ATLAS inner tracking detector and
calorimeters. Differential cross sections are presented as a function of the proton
fractional momentum loss, the four-momentum transfer squared, and the size of a
rapidity gap measured from the edge of the ATLAS calorimeters. The results are
interpreted in the framework of Regge phenomenology.