CP Phases in 2HDM and Effective Potential: A Geometrical View

Abstract

Using a geometric description of 2HDM, we classify CP invariants into three independent sectors such as scalar potential, Yukawa interaction and CKM matrix. Thermal effective potential of 2HDM is calculated in a basis invariant way. It is shown that the CP violation in Yukawa interactions can contribute to effective potential at one loop level but the CP phase in the CKM matrix cannot leak to effective potential at all orders. In the 2HDM with a softly broken Z2 symmetry, the leading thermal correction tends to restore the CP symmetry at high temperature.

Intermediate charge-breaking phases and symmetry non-restoration in the 2-Higgs-Doublet Model

“…The full model we consider in this work, which differs from the toy model by the presence of the soft Z 2 breaking m 2 12 term, can also be analyzed within the same geometric framework, at least at tree level (an extension of the geometric approach to the one-loop effective potential was recently developed in [85,86], but we do not rely on it in this work). The phase diagram now acquires two additional dimensions defined by the real and imaginary parts of m 2 12 .…”