Dr Robert Astalos (Comenius University Bratislava)
The ATLAS Collaboration released several new measurements in the area of SoftQCD and diffractive physics, ranging from the exclusive production of dimuons, over the total pp cross section measurement to studies of correlated hadron production. An overview of these most recent developments will be given in this talk: The total inelastic proton-proton cross section and the diffractive part of the inelastic cross section has been measured at 8 and 13 TeV in special data sets taken with low beam currents and using forward scintillators. More precise measurements of the total pp cross section and the elastic and inelastic contributions have been extracted from measurements of the differential elastic cross section using the optical theorem. In the absence of forward proton tagging, exclusive processes can be distinguished in the central part of the ATLAS detector exploiting the large rapidity gap in the central region and the absence of charged particles reconstructed in the inner tracking detector. This strategy has been exploited to study the exclusive production of dilepton pairs in the data taken at centre-of-mass energies of 7 TeV and the exclusive production of W pairs in the 8TeV data. We present recent results on exclusive dimuon production at 13 TeV. Last but not leasts, new studies of correlated hadron production have been conducted, as they are an important source of information about the early stages of hadron formation, not yet understood from first principles. Although experimental high energy physics employs several semi–classical models of hadronization which describe the formation of jets with remarkable accuracy, correlation phenomena are more elusive.