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We discuss different approaches to photon isolation in fixed-order calculations and present a new next-to-next-to-leading order (NNLO) QCD calculation of $R_{13/8}^��$, the ratio of the inclusive isolated photon cross section at 8 TeV and 13 TeV, differential in the photon transverse momentum, which was recently measured by the ATLAS collaboration., 4 pages, 1 figure. Contribution to the 2019 QCD session of the 54th Rencontres de Moriond

To compare the amount of angiotensin-converting enzyme (ACE) activity in pulmonary artery endothelial cells from different sites and to examine the effect of severe hypoxia (less than 1% of O(2) in 5% CO(2) and 95% N(2)) on the ACE activity expressed by these cells, endothelial cells were harvested and cultured from canine main pulmonary artery by scraping the luminal surface of the artery and from canine pulmonary artery microvessels by infusing chilled buffer with microcarrier beads and 0.02% ethylenediamine tetraacetic acid (EDTA). ACE activity in cell lysates and culture medium was evaluated by fluorometric assay with hippuryl-L-histidyl-L-leucine as a substrate. ACE activity in cell lysates and postculture medium of pulmonary microvascular endothelial cells (PMVEC) was higher than in cell lysates and culture medium of central pulmonary artery endothelial cells (PAEC). However, hypoxia suppressed cellular ACE activity in both PAEC and PMVEC. The degree of suppression of ACE activity by hypoxia, which was determined as (ACE activity in normoxia - ACE activity in hypoxia)/ACE activity in normoxia x 100(%), was larger in PMVEC than in PAEC. The pulmonary microvasculature may be a greater source of ACE than central pulmonary artery, and the ACE activity of pulmonary microvascular endothelial cells seem to be sensitive to hypoxia, although the small diameter of the vessels improves conditions for interaction of blood-borne substance with endothelial enzymes.

Inclusive Higgs boson production at large transverse momentum is induced by different production channels. We focus on the leading production through gluon fusion, and perform a consistent combination of the state of the art calculations obtained in the infinite-top-mass effective theory at next-to-next-to-leading order (NNLO) and in the full Standard Model (SM) at next-to-leading order (NLO). We thus present approximate QCD predictions for this process at NNLO, and a study of the corresponding perturbative uncertainties. This calculation is then compared with those obtained with commonly used event generators, and we observe that the description of the considered kinematic regime provided by these tools is in good agreement with state of the art calculations. Finally, we present accurate predictions for other production channels such as vector boson fusion, and associated production with a gauge boson, and with a $t\bar{t}$ pair. We find that, at large transverse momentum, the contribution of other production modes is substantial, and therefore must be included for a precise theory prediction of this observable., 15 pages, 4 figures, 9 tables. Version approved by the Higgs Cross Section Working Group

The Drell-Yan process at hadron colliders is a fundamental benchmark for the study of strong interactions and the extraction of electroweak parameters. The outstanding precision of the LHC demands very accurate theoretical predictions with a full account of fiducial experimental cuts. In this Letter we present a state-of-the-art calculation of the fiducial cross section and of differential distributions for this process at third order in the strict fixed-order expansion in the strong coupling, as well as including the all-order resummation of logarithmic corrections. Together with these results, we present a detailed study of the subtraction technique used to carry out the calculation for different sets of experimental cuts, as well as of the sensitivity of the fiducial cross section to infrared physics. We find that residual theory uncertainties are reduced to the percent level and that the robustness of the predictions can be improved by a suitable adjustment of fiducial cuts. The Drell-Yan process at hadron colliders is a fundamental benchmark for the study of strong interactions and the extraction of electro-weak parameters. The outstanding precision of the LHC demands very accurate theoretical predictions with a full account of fiducial experimental cuts. In this letter we present a state-of-the-art calculation of the fiducial cross section and of differential distributions for this process at third order in the strict fixed-order expansion in the strong coupling, as well as including the all-order resummation of logarithmic corrections. Together with these results, we present a detailed study of the subtraction technique used to carry out the calculation for different sets of experimental cuts, as well as of the sensitivity of the fiducial cross section to infrared physics. We find that residual theory uncertainties are reduced to the percent level and that the robustness of the predictions can be improved by a suitable adjustment of fiducial cuts.

Work on electroweak precision calculations and event generators for electroweak physics studies at current and future colliders is summarized.