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A Twisted Custodial Symmetry in the Two-Higgs-Doublet Model

J. -M. Gerard·M. Herquet
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Abstract

In the Standard Model for electroweak interactions, the Higgs sector is known to display a "custodial" symmetry protecting the mass relation m_{W^\pm}^2=m_{W_3}^2 from large corrections. When considering extensions of the scalar sector, this symmetry has to be introduced by hand in order to pass current electroweak precision tests in a natural way. In this Letter we implement a generalized custodial symmetry in the two-Higgs-doublet model. Assuming the invariance of the potential under CP transformations, we prove the existence of a new custodial scenario characterized by m_{H^\pm}^2=m_{H^0}^2 instead of m_{H^\pm}^2=m_{A^0}^2. Consequently the pseudoscalar A^0 may be much lighter than the charged H^\pm, giving rise to interesting phenomenology.

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J. -M. Gerard, M. Herquet. 2007-03-05. A Twisted Custodial Symmetry in the Two-Higgs-Doublet Model. https://doi.org/10.1103/physrevlett.98.251802

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