Probing light top partners with CP violation

TL;DR

This paper explores how light top partners in composite Higgs models induce CP violation, affecting electric dipole moments and providing bounds comparable to collider searches, with future experiments promising to probe higher mass ranges.

Contribution

It demonstrates that CP-violating effects from light top partners generate significant dipole moments at two loops, linking low-energy observables to top partner properties.

Findings

Current EDM constraints set top partner mass bounds of a few TeV.

Future EDM measurements could probe top partner masses beyond 10 TeV.

CP-violation effects are connected to operators influencing top partner production.

Abstract

We investigate CP-violating effects induced by light top partners in composite Higgs theories. We find that sizable contributions to the dipole moments of the light SM quarks and leptons are generically generated at the two-loop level through Barr-Zee-type diagrams. The present constraints on the electron and neutron electric dipole moments translate into bounds on top partner masses of order few TeV and are competitive with the reach of LHC direct searches. Interestingly, we find that CP-violation effects are sensitive to the same operators that control top partner single production. Near-future improvements in the determination of the electron dipole moment will extend the reach on top partner masses beyond the 5 - 10 TeV range.