Eur. Phys. J. C (2014) 74: 3065
https://doi.org/10.1140/epjc/s10052-014-3065-2

Regular Article - Theoretical Physics

Higgs characterisation at NLO in QCD: CP properties of the top-quark Yukawa interaction

¹ Centre for Cosmology, Particle Physics and Phenomenology (CP3), Université catholique de Louvain, 1348, Louvain-la-Neuve, Belgium
² Theoretische Natuurkunde and IIHE/ELEM, Vrije Universiteit Brussel, and International Solvay Institutes, Pleinlaan 2, 1050, Brussels, Belgium
³ Departamento de Física Teórica y del Cosmos y CAFPE, Universidad de Granada, Granada, Spain
⁴ Sorbonne Universités, UPMC University Paris 06, UMR 7589, LPTHE, 75005, Paris, France
⁵ CNRS, UMR 7589, LPTHE, 75005, Paris, France

^* e-mail: kentarou.mawatari@vub.ac.be

Received: 29 July 2014
Accepted: 2 September 2014
Published online: 23 September 2014

Abstract

At the LHC the CP properties of the top-quark Yukawa interaction can be probed through Higgs production in gluon fusion or in association with top quarks. We consider the possibility for both CP-even and CP-odd couplings to the top quark to be present, and study CP-sensitive observables at next-to-leading order (NLO) in QCD, including parton-shower effects. We show that the inclusion of NLO corrections sizeably reduces the theoretical uncertainties, and confirm that di-jet correlations in jet production through gluon fusion and correlations of the top-quark decay products in production can provide sensitive probes of the CP nature of the Higgs interactions.