High-lights of the ATLAS and ALICE experiments

Abstract

On behalf of the ATLAS and ALICE collaborationsThe ATLAS experiment has achieved important new physics results in particular in the Higgs area using the large proton-proton collision data-sets at a centre-of-mass energy of 13 TeV. The Yukawa coupling of the Higgs boson to fermions was established with the direct observation of the production of the Higgs boson with a top quark pair and the observation of the Higgs boson decay to beauty quarks. The four main production modes of the Higgs boson have now been observed. The couplings to all heavy particles (Z/W-boson, top and bottom quark and tau-lepton) are observed and already measured with good precision. It is experimentally confirmed that the Higgs boson couplings strongly depend on the particle mass. ATLAS also observed a few important electroweak diboson processes and measured their crosssection and some properties. For some of these processes it is the first observation by the ATLAS experiment. A preliminary measurement of the electroweak mixing angle accomplished a 15% precision using Drell-Yan cross-section measurements at a centre-of-mass energy of 8 TeV. Measurements of spin correlations between top quark pairs show that a discrepancy with NLO QCD. New measurements of top quark pair production in association with beauty quark pairs show a 50% normalisation difference with respect to most recent QCD calculations. The ALICE experiments studies particle production in proton-proton and heavy-ion collisions in great detail. New results on strange particle production and baryon-to-meson ratio lead to a consistent picture in proton-proton, xenon-xenon and lead-lead collisions. Models of collective flow measurements tuned in lead-lead collisions can also describe the xenon-xenon data showing that the initial matter distributions in the collisions and the expansion dynamics of the hot and dense nuclear medium are well understood. Moreover, detailed measurements of D-meson demonstrate a quantitative understanding of charm transport.