tWH associated production at the LHC

Area of Science:

• High Energy Physics
• Quantum Chromodynamics (QCD)
• Standard Model of Particle Physics

Background:

• Higgs boson production in association with a top quark and a W boson (tWH) is a key process at the Large Hadron Collider (LHC).
• At next-to-leading order (NLO) in QCD, tWH production interferes with top quark and W boson production (tW), necessitating careful separation for precise analysis.
• Existing techniques for handling intermediate resonances in NLO calculations, like diagram removal and subtraction, require critical evaluation in the context of tW and tWH production.

Purpose of the Study:

• To define tWH production for both total rates and differential distributions by employing and critically assessing diagram removal and subtraction techniques.
• To provide robust theoretical predictions for total and differential cross-sections of tW and tWH production at 13 TeV.
• To investigate the sensitivity of tWH production to non-Standard-Model physics, specifically a relative phase between Higgs couplings to the top quark and W boson.

Main Methods:

• Revisiting the tW production process to understand analogous interferences with t-channel single top production.
• Applying diagram removal and subtraction techniques to define and calculate NLO QCD cross-sections for tWH and tW production.
• Matching short-distance events to parton shower simulations and developing a reliable prescription for estimating theoretical uncertainties.

Main Results:

• Robust predictions for total and differential cross-sections for tW and tWH production at 13 TeV are presented.
• A reliable method for estimating theoretical uncertainties, including those related to the NLO definition of the process, has been formulated.
• The study quantifies the sensitivity of tWH production to a potential non-Standard-Model relative phase in Higgs couplings.

Conclusions:

• The developed techniques and robust cross-section calculations for tWH and tW production are crucial for precision measurements at the LHC.
• The methodology provides a framework for handling interfering processes at NLO, essential for comparing theoretical predictions with experimental data.
• The sensitivity study of tWH production to new physics offers a potential avenue for discovering physics beyond the Standard Model.