High-lights of the ATLAS and ALICE experiments

Tancredi Carli, ATLAS and ALICE collaborations
2019 Proceedings of The 39th International Conference on High Energy Physics — PoS(ICHEP2018)   unpublished
On behalf of the ATLAS and ALICE collaborations The 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
more » ... ave 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.
doi:10.22323/1.340.0693 fatcat:zooq2by2dvg2fixwmzajkg5ynu