Measurements of single diffraction using forward proton tagging at ATLAS

ATLAS forward proton tagging detectors are presented. The ATLAS results on the elastic scattering using the ALFA detectors are summarised. The main part of the talk focuses on the recent measurement of single diffractive dissociation using forward proton tagging at ATLAS. The intact proton is reconstructed and measured in the ALFA forward spectrometer, while charged particles from the dissociated system are measured by the ATLAS tracking detector. 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 tracker. The results are interpreted in the framework of Regge phenomenology.