### Abstract

We compute the cross section for e^{+}e^{-} → vv̄A^{0} in the general CP-conserving type-II two-Higgs-doublet model. We sum the contributions from the "t-channel" e ^{+}e^{-} → vv̄WW → vv̄A^{0} graphs and "s-channel" e^{+}e^{-} → ZA^{0} → vv̄A^{0} graphs, including their interference. Higgs-triangle graphs and all box diagrams are included. For many parameter choices, especially those in the decoupling region of parameter space (light h^{0} and m_{A0},m_{H0},m_{H±} > 2m_{Z}), the Higgs-triangle and box diagrams are found to be of minor importance, the main contributing loops being the top and bottom quark triangle diagrams. The predicted cross section is rather small for tan β>2 and/or m_{A0} > 2m_{t}. However, we also show that if parameters are chosen corresponding to large Higgs self-couplings then the Higgs-triangle graphs can greatly enhance the cross section. We also demonstrate that the supersymmetry-loop corrections to the bb̄A^{0} coupling could be such as to greatly enhance this coupling, resulting in an enhanced vv̄A^{0} cross section. Complete cross-section expressions are given in the Appendixes.

Original language | English (US) |
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Article number | 075006 |

Journal | Physical Review D - Particles, Fields, Gravitation and Cosmology |

Volume | 68 |

Issue number | 7 |

DOIs | |

Publication status | Published - 2003 |

Externally published | Yes |

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### ASJC Scopus subject areas

- Physics and Astronomy (miscellaneous)
- Physics and Astronomy(all)
- Nuclear and High Energy Physics
- Mathematical Physics

### Cite this

^{+}e

^{-}→ vv̄A

^{0}in the two-Higgs-doublet model.

*Physical Review D - Particles, Fields, Gravitation and Cosmology*,

*68*(7), [075006]. https://doi.org/10.1103/PhysRevD.68.075006