Perturbative Higgs CP violation, unitarity and phenomenology
  Perturbative probability conservation provides a strong constraint on the presence of new interactions of the Higgs boson. In this work we consider CP violating Higgs interactions in conjunction with unitarity constraints in the gauge-Higgs and fermion-Higgs sectors. Injecting signal strength measurements of the recently discovered Higgs boson allows us to make concrete and correlated predictions of how CP-violation in the Higgs sector can be directly constrained through collider searches for either characteristic new states or tell-tale enhancements in multi-Higgs processes. 
Christoph Englert, Karl Nordstr\"om, Kazuki Sakurai and Michael   Spannowsky
hep-ph hep-ex