ATLAS tunes of Pythia8 and Powheg and PDF sensitivity of prompt photon and dijet measurements

Tuning of Monte Carlo generator parameters and precise determination of parton distribution functions are of fundamental importance for the physics at the LHC. For example, the uncertainty of the W mass measurement and the Higgs cross-section predictions can be reduced by including ATLAS data into the Monte Carlo tunes and global parton density fits. New Pythia8 and Powheg+Pythia8 tunes are presented, based on the ATLAS measurement of the Z transverse momentum distribution using the $\phi^{*}_{\eta}$ variable. The ATLAS measurements of the inclusive photon and dijet production cross sections are compared to predictions based on different sets of parton densities. Sensitivity of these data to the gluon content of the proton is demonstrated in a quantitative way.