Dortmund 2021 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

T: Fachverband Teilchenphysik

T 9: Associated Higgs production and Higgs quantum numbers I

T 9.8: Talk

Monday, March 15, 2021, 17:45–18:00, Ti

Modelling studies of the tt+bb background to the tt(H→ bb) analysis — •Stephen Eggebrecht, Andreas Kirchhoff, Arnulf Quadt, Elizaveta Shabalina, and Knut Zoch — II. Physikalisches Institut, Georg-August-Universität Göttingen

The measurement of the Yukawa coupling of the Higgs boson to the top quark is an important parameter of the Standard Model (SM). It could be used to either find deviations from the SM or to constrain BSM theories. To study this coupling, the production of a SM Higgs boson in association with a top-quark pair is used. The decay mode where the SM Higgs boson decays to bottom quarks has the highest branching ratio. Unfortunately, it suffers from a large tt+bb background. It has a two times larger cross-section than the signal as well as similar kinematics. By reducing the modelling uncertainties of the tt+bb background, a better sensitivity of the measurement can be achieved. For this purpose, four different Monte Carlo (MC) simulations are compared. All simulations have different generator tunes and parton distribution function (PDF) sets. Firstly, the kinematics of the additional b-jets are studied when the tt+bb process is simulated in the 5-flavour scheme. Secondly, a comparison is made with tt+bb kinematics simulated in the 4-flavour scheme, where the bottom quark is no longer treated as a massless particle. This treatment corresponds to the best available theoretical predictions and is expected to reduce the uncertainties on this background.