2nd Weekly High Energy Physics Seminar 2022

During March the 1st, following a successful seminar last week with more than 120 attendees, a new weekly ATLAS related talk will be held, as part of the talks organized by the 'Theory Meets Experiment at ATLAS LHC (ACT1406)', which are going to be held at Aula Magna UTFSM, Valparaiso, Chile. The second talk will be given by Dr. David Zakareishvili: ATLAS measurement of the two-particle correlation sensitivity to jets in proton-proton collisions Measurements of two-particle correlations in proton-proton collisions show the presence of long-range correlations along $\Delta\eta$ that are strikingly similar to those seen in heavy-ion collisions. In larger systems, the long-range correlations are known to arise from the collective dynamics of the produced quark-gluon plasma (QGP). The similarity between the $pp$ and heavy-ion measurements raises the possibility that a tiny droplet of the QGP is produced even in $pp$. However, models that attribute the correlation in $pp$ collisions to semi-hard processes can qualitatively reproduce the measurements. Thus performing the $pp$ measurements with distinguishing particles associated with semi-hard processes, such as low-$p_{\mathrm{T}}$ jets, can further elucidate the origin of the long-range correlations. This talk presents a new measurements of two-particle correlations in $pp$ collisions at $\sqrt{s}=13$ TeV with two different particle pair selections. In the first case, tracks associated with jets are excluded from the correlation analysis. This case results in a minor influence on the magnitude of the long-range correlation. In the second case, the two-particle correlations are measured between jet constituents and the underlying-event tracks. In this case, the correlations show no ridge-like structure.