Low energy phenomena have been studied in detail at the LHC, providing important input for improving models of non-perturbative QCD effects. The ATLAS collaboration has performed several new measurements in this sector:
We present charged-particle distributions sensitive to the underlying event, measured by the ATLAS detector in proton--proton collisions at a centre-of-mass energy of 13 TeV....
In high energy physics, exclusive processes are special type of collisions, where both colliding particles remain intact and we observe all of the produced particles. These can be either electroweak (two-photon fusion), strong (double pomeron exchange) or mixed electromagnetic and strong (photoproduction) processes. One of the greatest advantage of these collisions is that there are...
The impact of nonlinear interaction effects on the total proton-proton cross section is studied. In particular, the relative roles of the perturbative and nonperturbative parton splitting mechanisms are investigated. Additionally, the importance of dynamical higher twist corrections to parton production processes is demonstrated.
We present results on measurements of characteristics of events with jets, from jet-charge over investigations of shapes to jet mass distributions. The measurements are compared to theoretical prediction including those matched to parton shower and hadronization.
We present measurements of multi-differential Jet cross sections over a wide range in transverse momenta from inclusive jets to multi-jet final states. We present studies on the impact these measurements have on the determination of the strong coupling alphas as well as on parton density functions. We also show angular correlations in multi-jet events at highest center-of-mass energies and...
Abstract:
We have developed a new procedure to determine Parton Distribution Functions (PDFs) and their uncertainties, based on Markov Chain Monte Carlo methods. We will show in this talk how we can replace the standard $\chi^2$ minimization by procedures grounded on Statistical Methods, and on Bayesian inference in particular, thus offering additional insight into the rich field of PDFs. The...
