Basis-independent treatment of the complex 2HDM

The complex 2HDM (C2HDM) is the most general CP-violating two Higgs-doublet-model that possesses a softly broken Z2 symmetry. However, the physical consequences of the model cannot depend on the basis of scalar fields used to define it. Thus, to get a better sense of the significance of the C2HDM pa...

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Bibliographic Details
Published in:Physical review. D 2020-03, Vol.101 (5), p.1
Main Authors: Boto, Rafael, Fernandes, Tiago V, Haber, Howard E, Romão, Jorge C, Silva, João P
Format: Article
Language:English
Subjects:
Ambiguity
CP violation
Formalism
Mathematical models
Parameters
Scalars
Symmetry
Online Access:Get full text
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Summary:The complex 2HDM (C2HDM) is the most general CP-violating two Higgs-doublet-model that possesses a softly broken Z2 symmetry. However, the physical consequences of the model cannot depend on the basis of scalar fields used to define it. Thus, to get a better sense of the significance of the C2HDM parameters, we have analyzed this model by employing a basis-independent formalism. This formalism involves transforming to the Higgs basis (which is defined up to an arbitrary complex phase) and identifying quantities that are invariant with respect to this phase degree of freedom. Using this method, we have obtained the constraints that enforce the softly broken Z2 symmetry. One can then relate the C2HDM parameters to basis-independent quantities up to a twofold ambiguity. We then show how this remaining ambiguity is resolved. We also examine the possibility of spontaneous CP violation when the scalar potential of the C2HDM is explicitly CP conserving. Basis-independent constraints are presented that govern the presence of spontaneous CP violation.
ISSN:2470-0010
2470-0029
DOI:10.1103/PhysRevD.101.055023