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Subjects: Physics >> The Physics of Elementary Particles and Fields

We examine various direct and indirect constraints on the lepton-specific two-Higgs-doublet model and scrutinize the property of the Higgs bosons in the allowed parameter space. We find that in the allowed parameter space the CP-odd Higgs boson A is rather light (m(A) < 30 GeV with 95% possibility), which is composed dominantly by the leptonic Higgs and decays dominantly into tau(+) tau(-); while the standard-model-like Higgs boson h (responsible largely for electroweak symmetry breaking) decays dominantly in the mode h -> AA -> 4 tau with a large decay width, which will make the Higgs discovery more difficult at the LHC, whereas this scenario predicts a branching ratio Br(Z -> tau(+) tau(-) A) ranging from 10(-5) to 10(-4), which may be accessible at the GigaZ option of the International Linear Collider. |

Pair production of a 125 GeV Higgs boson in MSSM and NMSSM at the LHC

Cao, Junjie; Heng, Zhaoxia; Shang, Liangliang; Wan, Peihua; Yang, Jin MinSubjects: Physics >> The Physics of Elementary Particles and Fields

In light of the recent LHC Higgs search data, we investigate the pair production of a SM-like Higgs boson around 125 GeV in the MSSM and NMSSM. We first scan the parameter space of each model by considering various experimental constraints, and then calculate the Higgs pair production rate in the allowed parameter space. We find that in most cases the dominant contribution to the Higgs pair production comes from the gluon fusion process and the production rate can be greatly enhanced, maximally 10 times larger than the SM prediction (even for a TeV-scale stop the production rate can still be enhanced by a factor of 1.3). We also calculate the chi(2) value with the current Higgs data and find that in the most favored parameter region the production rate is enhanced by a factor of 1.45 in the MSSM, while in the NMSSM the production rate can be enhanced or suppressed (sigma(SUSY)/sigma(SM) varies from 0.7 to 2.4). |

The SM extension with color-octet scalars: diphoton enhancement and global fit of LHC Higgs data

Cao, Junjie; Wan, Peihua; Yang, Jin Min; Zhu, JingyaSubjects: Physics >> The Physics of Elementary Particles and Fields

In light of the significant progress of the LHC to determine the properties of the Higgs boson, we investigate the capability of the Manohar-Wise model in explaining the Higgs data. This model extends the SM by one family of color-octet and isospin-doublet scalars, and it can sizably alter the coupling strengths of the Higgs boson with gluons and photons. We first examine the current constraints on the model, which are from unitarity, the LHC searches for the scalars and the electroweak precision data (EWPD). In implementing the unitarity constraint, we use the properties of the SU(3) group to simplify the calculation. Then in the allowed parameter space we perform a fit of the model, using the latest ATLAS and CMS data, respectively. We find that the Manohar-Wise model is able to explain the data with chi(2) significantly smaller than the SM value. We also find that the current Higgs data, especially the ATLAS data, are very powerful in further constraining the parameter space of the model. In particular, in order to explain the gamma gamma enhancement reported by the ATLAS collaboration, the sign of the hgg coupling is usually opposite to that in the SM. |

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