Measurements of multiparton interactions at ATLAS

Apr 11, 2019, 8:56 AM
Palazzo Badini-Confalonieri - Sala Lauree

Palazzo Badini-Confalonieri - Sala Lauree

Via Verdi, 10 Turin
Parallel Session Talk WG2: Low-x and Diffraction Joint WG2+WG4: Small-x and Diff + Hadronic and EW


Lennart Adam (Johannes Gutenberg Universitaet Mainz (DE))


Measurements of multiple parton scattering in proton-proton collisions provide insight into the structure and long-range low-momentum scale interactions of the proton. In this talk we present two recent measurements using proton-proton collision data collected by the ATLAS experiment. The first measurement determines the double-parton scattering contribution to four-lepton events at √s=8 TeV. An artificial neural net is used to optimise the analysis and an upper limit on the double-parton scattering fraction is set at 0.042, which corresponds to an effective cross section of 1mb. In the second measurement, the underlying event activity is studied in events containing a Z-boson in √s=13 TeV data. Unfolded differential cross sections are presented for charged particle multiplicity and charged particle transverse momentum in regions of azimuth measured with respect to the Z-boson direction. The data are compared to a wide variety of predictions from Monte Carlo event generators.

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