Underlying events and particle production in ATLAS

Particle distributions sensitive to the underlying event and to double-parton interactions have been measured with the ATLAS detector at the LHC at the center-of-mass energy of 7 TeV. Charged-particle multiplicity, charged and inclusive transverse momentum sum densities and the mean transverse momentum of charged particles are presented in the region of each event azimuthally transverse to the direction of the hard scattering. In addition measurements of the sum of the transverse energy of particles as a function of the particle pseudorapidity and the production of W bosons in association with two jets in proton-proton collisions are presented. Comparisons to the predictions of various Monte Carlo models show the sensitivity of the data to the modeling of the underlying event and double-parton interactions.