- The paper introduces a NLO QCD calculation for Higgs production via VBF, integrating NLO corrections with POWHEG for enhanced event simulation.
- It employs innovative techniques such as parton line tagging and tuning real corrections to efficiently handle singular regions.
- Numerical results show modest yet reliable corrections, supporting refined experimental strategies for LHC Higgs studies.
Next-to-Leading Order Higgs Boson Production via Vector-Boson Fusion with POWHEG
This paper presents a detailed methodology for Higgs boson production in vector-boson fusion (VBF) at next-to-leading order (NLO) in QCD, integrated with shower Monte Carlo simulations through the POWHEG framework. The research is pivotal for advancing Higgs boson studies, particularly in the context of the Large Hadron Collider (LHC) at CERN. VBF is a significant mechanism for Higgs production after gluon fusion, offering valuable insights into the Higgs boson couplings when observed in various decay channels such as H→ττ, H→WW, and H→γγ.
This work implements the NLO calculation using the POWHEG BOX, an automated system designed to seamlessly combine NLO processes with parton showers. The implementation introduces key improvements, such as tagging parton lines and tuning the contribution of real corrections, which address specific challenges in modeling VBF processes, such as the efficient handling of flavor combinatorics and large ratios of real to Born cross sections, respectively.
Key Methodological Advances
- Tagging Parton Lines: The paper introduces a method to differentiate quark lines in singular region identification, reducing errors in singularity handling during numerical calculations. This allows more accurate representation of the VBF process by appropriately classifying jet emissions along identified quark lines.
- Tuning of Real Corrections: A novel approach separates the real cross section into singular and nonsingular components, allowing more efficient generation of events with POWHEG's Sudakov form factor while isolating regions where larger deviations from NLO calculations occur.
Numerical Results
The paper reports that NLO corrections to VBF Higgs production are modest, generally between 5% and 10%, but can reach upwards of 30% for specific kinematic distributions. Scale uncertainties are minimal, suggesting high reliability of the predictions. Additionally, the analysis reveals that the integration with POWHEG maintains the characteristic features observed in differential cross sections for key variables, such as rapidity and invariant mass of tagging jets. The azimuthal angle correlation between jets, significant for studying the CP structure of Higgs interactions, remains mostly unaffected by the parton shower.
Implications and Future Directions
The POWHEG-enhanced simulations offer improved precision in predicting VBF Higgs processes at the LHC. By accurately modeling the influence of parton showers, the study enhances our ability to differentiate between Higgs production modes and backgrounds, which is crucial for precise measurements of the Higgs coupling parameters. The methodology also facilitates further explorations into jet activity and central jet veto strategies, which can be instrumental in refining experimental strategies at the LHC.
Looking forward, this work sets the stage for further development of combined NLO and parton shower techniques applicable to other processes beyond VBF and Higgs boson production. Future research might entail extending these methodologies to more complex events or integrating them seamlessly with different Monte Carlo event generators to explore discrepancies that arise from various showering approaches and their impact on experimentally observable signatures.
The enhancement of POWHEG with the capabilities outlined in this paper marks a significant step towards more comprehensive simulations in high-energy physics, offering valuable insights for both theoretical advancements and experimental applications in the study of the Higgs boson at the LHC.