Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables

Abstract: This Report summarizes the results of the first 10 months' activities of the LHC Higgs Cross Sections Working Group. The main goal of the working group was to present the status-of-art on Higgs Physics at the LHC integrating all new results that have appeared in the last few years. The Report is more than a mere collection of the proceedings of the general meetings. The subgroups have been working in different directions. An attempt has been made to present the first Report from these subgroups in a complete and homogeneous form. The subgroups' contributions correspondingly comprise the main parts of the Report. A significant amount of work has been performed in providing higher-order corrections to the Higgs-boson cross sections and pinning down the theoretical uncertainty of the Standard Model predictions. This Report comprises explicit numerical results on total cross sections, leaving the issues of event selection cuts and differential distributions to future publications. The subjects for further study are identified.

• The paper provides state-of-the-art theoretical predictions of Higgs boson production cross sections across key mechanisms like gluon-gluon fusion, vector-boson fusion, and associated production.
• It employs advanced QCD calculations with NNLO corrections along with electroweak adjustments to reduce theoretical uncertainties.
• The work enhances understanding of Higgs production in both the Standard Model and MSSM, offering a robust framework for interpreting LHC experimental data.

Overview of the "Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables"

The "Handbook of LHC Higgs Cross Sections: 1. Inclusive Observables" is a comprehensive report prepared by the LHC Higgs Cross Section Working Group. The document serves as a pivotal resource for physicists engaged in Higgs boson research and provides an in-depth analysis of the theoretical and numerical predictions of Higgs boson production cross-sections within the framework of the Standard Model (SM) and the Minimal Supersymmetric Standard Model (MSSM).

Key Contributions and Methodologies

The report is primarily focused on delivering precise theoretical predictions for various Higgs boson production processes at the LHC. The significant production mechanisms covered include gluon-gluon fusion (ggF), vector-boson fusion (VBF), associated production with a vector boson (VH), and associated production with top quarks (ttH). Each chapter systematically details the state-of-the-art calculations, including quantum chromodynamics (QCD) corrections at next-to-leading order (NLO) and next-to-next-to-leading order (NNLO), electroweak (EW) corrections, and considerations for uncertainties owing to parton distribution functions (PDFs) and renormalization and factorization scales.

Gluon-Gluon Fusion

The ggF process is detailed as the dominant production mechanism for the SM Higgs boson at the LHC, especially at low to moderate Higgs masses. The report provides precise cross-section calculations incorporating NNLO QCD corrections, and it includes soft-gluon resummation effects to NNLL accuracy. The results are compared across different PDFs with a detailed assessment of theoretical uncertainties.

Vector-Boson Fusion

For VBF production, the report discusses NLO electroweak and QCD corrections and their implications on theoretical accuracy. The NNLO QCD corrections are particularly crucial for reducing uncertainties in the predictions. The working group achieves consensus across different computational tools such as HAWK and VBFNLO, ensuring reliability in theoretical predictions.

Associated Production with Vector Bosons

In the case of VH production, the emphasis is on understanding the intricacies of the NNLO QCD corrections combined with NLO EW corrections, crucial for a detailed understanding of the Higgs production together with W and Z bosons. The report underscores the importance of contributions from the gluon-gluon initial state in the case of ZH production.

Associated Production with Top Quarks

The ttH production process analysis benefits from full NLO QCD calculations and considerations of loop-induced SUSY effects. The report adds granularity by detailing the treatment of scale and PDF uncertainties, essential for the accurate prediction of cross sections.

Higgs Production in the MSSM

For MSSM scenarios, the report expands the investigation to include both neutral and charged Higgs bosons across various benchmark scenarios, which are critical for exploring diverse MSSM parameter spaces. Calculations involve dedicated tools like FeynHiggs and CPsuperH to incorporate radiative corrections broadening the utility of these results across different MSSM configurations.

Implications and Future Directions

The handbook serves as a definitive resource for experimentalists and theorists working with the LHC data, aiding in discriminating between signals consistent with the SM Higgs boson and potential new physics scenarios. The detailed breakdown of uncertainties provides a robust basis for future experiment-comparison work across different research centers. As the field advances, and as data collection continues, these theoretical predictions will further guide modifications and refinements in the pursuit of new physics beyond the SM.

In conclusion, the "Handbook of LHC Higgs Cross Sections" elucidates crucial theoretical frameworks and standardizes Higgs boson cross-section predictions for the LHC, marking a significant stride in understanding the dynamics of electroweak symmetry breaking. Its comprehensive treatment of cross-sectional computations ensures it remains a cornerstone document in particle physics research.