Apr 7 – 10, 2019
Imperial College London
Europe/London timezone

Measuring the top higgs couplings CP-nature in ttH(->bb) dilepton events.

Apr 8, 2019, 2:15 PM
Clore Lecture Theatre, Huxley 213 (Imperial College London)

Clore Lecture Theatre, Huxley 213

Imperial College London

Imperial College London Prince Consort Road South Kensington London


Nicolas Scharmberg (University of Manchester (GB))


The coupling strength of the higgs boson to fermions is predicted to be proportional to the fermions mass, making the higgs top coupling the strongest in the SM.
This coupling strength can be directly measured in the production of a higgs boson in combination with two top quarks, which was observed in 2018. In the SM, the higgs top coupling is predicted to be a CP-even coupling but measuring a CP-odd component would suggest physics beyond the SM.
I will present how the current data collected with the ATLAS experiment can be used for a measurement on the top higgs coupling.
I will concentrate on the case where both two top quarks decay leptonically and the higgs decays into a bbbar pair. In this decay channel, there are many challenges such as the two neutrinos and high multiplicity of jets in the final state. This talk will demonstrate the full event reconstruction including reconstruction of the top quarks using neutrino weighting. I will also present how kinematic variables in the event may be combined in MVA techniques to optimise the sensitivity of this measurement and allow us to set limits on the coupling parameters with existing and upcoming LHC data.

Presentation materials