Higgs production via gluon fusion in the POWHEG approach in the SM and in the MSSM

Abstract: We consider the gluon fusion production cross section of a scalar Higgs boson at NLO QCD in the SM and in the MSSM. We implement the calculation in the POWHEG approach, and match the NLO-QCD results with the PYTHIA and HERWIG QCD parton showers. We discuss a few representative scenarios in the SM and MSSM parameter spaces, with emphasis on the fermion and squark mass effects on the Higgs boson distributions.

• The paper presents a detailed NLO QCD analysis of Higgs production through gluon fusion using the POWHEG framework.
• It compares top and bottom quark loop effects and squark contributions between the SM and MSSM, revealing key cross-section deviations.
• The study integrates fixed-order computations with parton showering to improve precision in Higgs observables relevant to LHC experiments.

Analysis of Higgs Production via Gluon Fusion in the Standard Model and Minimal Supersymmetric Standard Model

The paper by Bagnaschi et al. explores the computational and phenomenological analysis of Higgs boson production through gluon fusion, within both the Standard Model (SM) and the Minimal Supersymmetric Standard Model (MSSM), focusing on next-to-leading order (NLO) QCD effects. The researchers utilize the POWHEG method, which involves combining fixed-order calculations with parton showering, facilitating precision in observables relevant to LHC experiments.

Key Features and Approach

The study implements a calculation based on the NLO QCD, contrasting the results of Higgs production mechanisms in both SM and MSSM. By integrating the POWHEG framework with PYTHIA and HERWIG event generators, the authors capture the subtleties of partonic scatterings and the associated uncertainties caused by QCD corrections. Importantly, care is taken to consider finite fermion masses, especially focusing on the top-quark contributions at NLO, with careful attention to the gluon-gluon-Higgs (ggH) vertex form factor and its dependence on quark and squark masses.

Numerical Results and Their Implications

The numerical analyses yield insights into the modifications induced by top and bottom quark loops on the Higgs production cross-sections and a detailed exploration of the role of superpartners, particularly squarks, in MSSM scenarios. The contribution from those can be either suppressive or enhancement, depending on mass hierarchies, with MSSM showing deviations from SM predictions particularly at high $and low pseudoscalar Higgs masses$.

One significant finding is the deviation in cross-section predictions for a light Higgs between SM and MSSM when $$ is large, highlighting areas of interest for experimental validation. The use of an exact mass-dependent NLO QCD treatment confirms a non-negligible impact on phenomenologically significant parameters, warranting further theoretical and experimental erosion of uncertainties associated with Higgs signatures.

Furthermore, the parton-shower matched predictions exhibit evolved transverse momentum distributions for the Higgs boson, indicating the importance of matching schemes on precision observable predictions at hadron colliders like LHC.

Contributions to Theoretical and Experimental Landscape

This research provides detailed theoretical scaffolding necessary for discerning the potential discovery of new physics signatures beyond the Standard Model. By comparing SM and MSSM Higgs production details, the study reveals potential distinguishing factors between them which could be exploited in searches at CERN's LHC. By quantifying the effects introduced through MSSM parameters and achieving greater computational accuracy, these results better align theoretical predictions with experimental data.

Future Directions

The complexity and scope of Higgs production processes will necessitate further refinements in dealing with higher order corrections beyond NLO, incorporating electroweak contributions and potential effects from other BSM scenarios. The quest for precision requires ongoing refinement of simulation frameworks and cross-validation with observable data from collider experiments to ensure robust scientific conclusions.

In summary, the paper by Bagnaschi et al. significantly contributes to the understanding of Higgs production processes by refining computational methodologies and setting the stage for enhanced analyses that can feed into and be validated by experimental discoveries in high-energy physics.