Higgs boson production via gluon-gluon fusion and vector-boson fusion in proton-proton collisions is measured in the H → WW *→ eνμν decay channel. The Large Hadron Collider delivered proton-proton ...collisions at a center-of-mass energy of 13 TeV between 2015 and 2018, which were recorded by the ATLAS detector, corresponding to an integrated luminosity of 139 fb −1 . The total cross sections for Higgs boson production by gluon-gluon fusion and vector-boson fusion times the H → WW* branching ratio are measured to be 12.0±1.4 and <img src="http://www.diva-portal.org/cgi-bin/mimetex.cgi?0.75_%7B-0.16%7D%5E%7B+0.19%7D" data-classname="equation" /> pb, respectively, in agreement with the Standard Model predictions of 10.4±0.6 and 0.81±0.02 pb. Higgs boson production is further characterized through measurements of Simplified Template Cross Sections in a total of 11 kinematic fiducial regions.
We present measurements of cross sections for production of a leptonically decaying Z boson in association with a large-radius jet in 13 TeV proton-proton collisions at the LHC, using 36 fb−1 of ...data from the ATLAS detector. Integrated and differential cross sections are measured at particle level in both a flavor inclusive and a doubly b-tagged fiducial phase space. The large-radius jet mass and transverse momentum, its kinematic relationship to the Z boson, and the angular separation of b-tagged small-radius track jets within the large-radius jet are measured. This measurement constitutes an important test of perturbative quantum chromodynamics in kinematic and flavor configurations relevant to several Higgs boson and beyond-Standard-Model physics analyses. The results highlight issues with modeling of additional hadronic activity in the flavor-inclusive selection, and a distinction between flavor-number schemes in the b-tagged phase space.
Measurements of the suppression and correlations of dijets is performed using 3µb−1 of Xe+Xe data at √sNN=5.44 TeV collected with the ATLAS detector at the CERN Large Hadron Collider. Dijets with ...jets reconstructed using the R=0.4 anti-kt algorithm are measured differentially in jet pT over the range of 32 to 398 GeV and the centrality of the collisions. Significant dijet momentum imbalance is found in the most central Xe+Xe collisions, which decreases in more peripheral collisions. Results from the measurement of per-pair normalized and absolutely normalized dijet pT balance are compared with previous Pb+Pb measurements at √sNN=5.02 TeV. The differences between the dijet suppression in Xe+Xe and Pb+Pb are further quantified by the ratio of pair nuclear-modification factors. The results are found to be consistent with those measured in Pb+Pb data when compared in classes of the same event activity and when taking into account the difference between the center-of-mass energies of the initial parton scattering process in Xe+Xe and Pb+Pb collisions. These results should provide input for a better understanding of the role of energy density, system size, path length, and fluctuations in the parton energy loss.
