Scale dependence and collinear subtraction terms for Higgs production in gluon fusion at N3LO

The full, explicit, scale dependence of the inclusive N3LO cross section for single Higgs hadroproduction is obtained by calculating the convolutions of collinear splitting kernels with lower-order partonic cross sections. We provide results for all convolutions of splitting kernels and lower-order partonic cross sections to the order in epsilon needed for the full N3LO computation, as well as their expansions around the soft limit. We also discuss the size of the total scale uncertainty at N3LO that can be anticipated with existing information.Comment: 27 pages, 8 figure, 1 table, 8 ancillary files. v2: added 4 references, changed labelling of contour plot

NLO QCD corrections to the production of t-tbar-Z in gluon fusion

We compute the O(alpha_s) QCD corrections to the partonic process gg -> t-tbar-Z at the LHC. This partonic channel is the dominant component of the scattering process pp -> t-tbar-Z, which will be important for measuring the t-tbar-Z electroweak couplings. The O(alpha_s) corrections increase the total cross section by up to 75% for reasonable choices of the renormalization and factorization scales. Inclusion of these contributions descreases the residual scale dependence of the cross section coming from uncalculated higher order terms to +-5%.Comment: 9 pages, 4 figure

iHixs 2 - Inclusive Higgs Cross Sections

We present a new release of the program iHixs. This easy-to-use tool allows to derive state of the art predictions for the inclusive production cross section of a Higgs boson at hadron colliders in the gluon fusion production mode. This includes the most up-to-date corrections in perturbative QCD and electro-weak theory, effects due to finite quark masses as well as an option to perform threshold resummation. In particular, exact perturbative QCD corrections through N3LO are included in the heavy top quark effective theory. Furthermore, iHixs contains automatic routines that allow to assess residual uncertainties on the prediction for the Higgs boson production cross section according to well established standard definitions. iHixs can be obtained from https://github.com/dulatf/ihixs .Comment: 46 pages, 3 awesome figure

QCD corrections to tri-boson production

We present a computation of the next-to-leading order QCD corrections to the production of three Z bosons at the LHC. We calculate these corrections using a completely numerical method that combines sector decomposition to extract infrared singularities with contour deformation of the Feynman parameter integrals to avoid internal loop thresholds. The NLO QCD corrections to pp -> ZZZ are approximately 50%, and are badly underestimated by the leading order scale dependence. However, the kinematic dependence of the corrections is minimal in phase space regions accessible at leading order.Comment: 15 pages, 3 figures; typos fixed, references and event listing adde

Error in Monte Carlo, quasi-error in Quasi-Monte Carlo

While the Quasi-Monte Carlo method of numerical integration achieves smaller integration error than standard Monte Carlo, its use in particle physics phenomenology has been hindered by the abscence of a reliable way to estimate that error. The standard Monte Carlo error estimator relies on the assumption that the points are generated independently of each other and, therefore, fails to account for the error improvement advertised by the Quasi-Monte Carlo method. We advocate the construction of an estimator of stochastic nature, based on the ensemble of pointsets with a particular discrepancy value. We investigate the consequences of this choice and give some first empirical results on the suggested estimators.Comment: 41 pages, 19 figure

Tree-level splitting amplitudes for a gluon into four collinear partons

We compute in conventional dimensional regularisation the tree-level splitting amplitudes for a gluon parent which splits into four collinear partons. This is part of the universal infrared behaviour of the QCD scattering amplitudes at next- to-next-to-next-to-leading order (N$^3$LO) in the strong coupling constant. Combined with our earlier results for a quark parent, this completes the set of tree-level splitting amplitudes required at this order. We also study iterated collinear limits where a subset of the four collinear partons become themselves collinear.Comment: 31 pages, 3 figures. arXiv admin note: substantial text overlap with arXiv:1912.0642

Matchmakereft: Automated tree-level and one-loop matching

Acknowledgments This has been a long project that has benefited from discussions with many people. We would like to thank F. del Águila, J. de Blas, C. Bobeth, M. Ciuchini, A. Freytas, J. Fuentes-Martín, G. Guedes, M. Gorbahn, U. Haisch, Z. Kunstz, M. Neubert, U. Nierste, M. Pérez-Victoria, A. Pich, E. Salvioni, A. Signer and M. Trott for useful discussions. We are especially grateful to C. Anastasiou for collaboration in the initial stages of the project, to M. Chala, for continuos discussions, suggestions and requests that allowed us to “milk matchmakereft for all its worth”, to T. Hahn, for patiently explaining many FORM tricks, and to G.P. Passarino, for daring us to “finish matchmakereft already!”. We would like to thank Nicolasa Navarrete for the design of the logo and her creative support. We would also like to thank the referees for their very detailed reports and Alejo Rossia for pointing some typos to us. This work has been partially supported by the Ministry of Science and Innovation and SRA (10.13039/501100011033) under grant PID2019-106087GB-C22, by the Junta de Andalucía grants FQM 101, A-FQM-211-UGR18 and P18-FR-4314 (FEDER). AC acknowledges funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 754446 and UGR Research and Knowledge Transfer Found - Athenea3i. PO is funded by an FPU grant from the Spanish government. Work in Mainz University by AC was supported by the Cluster of Excellence Precision Physics, Fundamental Interactions, and Structure of Matter (PRISMA+ EXC 2118/1) funded by the German Research Foundation(DFG) within the German Excellence Strategy (Project ID 39083149), and by grant 05H18UMCA1 of the German Federal Ministry for Education and Research (BMBF).We introduce matchmakereft, a fully automated tool to compute the tree-level and one-loop matching of arbitrary models onto arbitrary effective theories. Matchmakereft performs an off-shell matching, using diagrammatic methods and the background field method when gauge theories are involved. The large redundancy inherent to the off-shell matching together with explicit gauge invariance offers a significant number of non-trivial checks of the results provided. These results are given in the physical basis but several intermediate results, including the matching in the Green basis before and after canonical normalization, are given for flexibility and the possibility of further cross-checks. As a non-trivial example we provide the complete matching in the Warsaw basis up to one loop of an extension of the Standard Model with a charge -1 vector-like lepton singlet. Matchmakereft has been built with generality, flexibility and efficiency in mind. These ingredients allow matchmakereft to have many applications beyond the matching between models and effective theories. Some of these applications include the one-loop renormalization of arbitrary theories (including the calculation of the one-loop renormalization group equations for arbitrary theories); the translation between different Green bases for a fixed effective theory or the check of (off-shell) linear independence of the operators in an effective theory. All these applications are performed in a fully automated way by matchmakereft.Mainz University EXC 2118/1Spanish governmentHorizon 2020 Framework ProgrammeH2020 Marie Skłodowska-Curie Actions 754446Society for Research on Adolescence PID2019-106087GB-C22Deutsche Forschungsgemeinschaft 05H18UMCA1, 39083149Bundesministerium für Bildung und ForschungFEDERMinisterio de Ciencia e InnovaciónJunta de Andalucía A-FQM-211-UGR18, FQM 101, P18-FR-431

Thoracoabdominal aneurysm repair using a four-branched thoracoabdominal graft: a case series

Revascularization of the visceral arteries during thoracoabdominal aneurysm repair is usually performed sequentially by an anastomosis between a prosthetic graft and an aortic patch. There are immediate operative risks such as bleeding and distortion. In the longer term, aneurysm, pseudo-aneurysm and rupture may occur. These require reoperation and are associated with significant morbidity and mortality

Higgs production cross-section in a Standard Model with four generations at the LHC

We present theoretical predictions for the Higgs boson production cross-section via gluon fusion at the LHC in a Standard Model with four generations. We include QCD corrections through NLO retaining the full dependence on the quark masses, and the NNLO corrections in the heavy quark effective theory approximation. We also include electroweak corrections through three loops. Electroweak and bottom-quark contributions are suppressed in comparison to the Standard Model with three generations.Comment: 6 pages, 2 Tables, to appear in the proceedings of the XLVIth Rencontres de Moriond session devoted to Electroweak Interactions and Unified Theorie