We investigate methods to explore the CP nature of the ttˉh coupling at the LHC, focusing on associated production of the Higgs with a ttˉ pair. We first discuss the constraints implied by low-energy observables and by the Higgs-rate information from available LHC data, emphasizing that they cannot provide conclusive evidence on the nature of this coupling. We then investigate kinematic observables that could probe the ttˉh coupling directly, in particular quantities that can be constructed out of just lab-frame kinematics. We define one such observable by exploiting the fact that ttˉ spin correlations do also carry information about the CP-nature of the ttˉh coupling. Finally, we introduce a CP-odd quantity and a related asymmetry, able to probe CP violation in the ttˉh coupling and likewise constructed out of lab-frame momenta only.
@article{arxiv.1501.03157,
title = {Lab-frame observables for probing the top-Higgs interaction},
author = {Fawzi Boudjema and Rohini M. Godbole and Diego Guadagnoli and Kirtimaan A. Mohan},
journal= {arXiv preprint arXiv:1501.03157},
year = {2015}
}
Comments
32 pages, updated with latest data from ATLAS and references added