Direct and indirect constraints on CP-violating Higgs-quark and Higgs-gluon interactions

TL;DR

This paper analyzes how current and future experiments, including LHC data and electric dipole moment measurements, constrain CP-violating interactions of the Higgs boson with quarks and gluons, highlighting the importance of reducing theoretical uncertainties.

Contribution

It provides a comprehensive study of the constraints on CP-violating Higgs couplings from both collider and EDM experiments, emphasizing the role of theoretical uncertainties and future improvements.

Findings

Current bounds mainly from EDMs and LHC Run 1 data.

LHC Run 2 measurements will not significantly improve constraints.

Future EDM experiments could greatly enhance bounds on Higgs CP-violating interactions.

Abstract

We investigate direct and indirect constraints on the complete set of anomalous CP-violating Higgs couplings to quarks and gluons originating from dimension-6 operators, by studying their signatures at the LHC and in electric dipole moments (EDMs). We show that existing uncertainties in hadronic and nuclear matrix elements have a significant impact on the interpretation of EDM experiments, and we quantify the improvements needed to fully exploit the power of EDM searches. Currently, the best bounds on the anomalous CP-violating Higgs interactions come from a combination of EDM measurements and the data from LHC Run 1. We argue that Higgs production cross section and branching ratios measurements at the LHC Run 2 will not improve the constraints significantly. On the other hand, the bounds on the couplings scale roughly linearly with EDM limits, so that future theoretical and experimental EDM developments can have a major impact in pinning down interactions of the Higgs.