Tuesday, March 12, 2013

1303.2426 (Junjie Cao et al.)

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

Junjie Cao, Peihua Wan, Jin Min Yang, Jingya Zhu
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 to explain 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). Then in the allowed parameter space we perform a fit of the model using the latest Higgs data. From our analysis we obtain three main observations. The first is that in its broad parameter region this model is better than the SM in explaining the data. Especially, the best-fit points can be achieved for the charged color-octet scalar in the range of 300-750 GeV. The second is that the current Higgs data can stringently constrain the parameter space of this model, which, combined with the EWPD, strongly prefer the degeneracy of the charged scalar with the color-octet CP-odd scalar and also restrain the parameter \lambda_1 within a narrow region. And the last is that the best-fit points predict the couplings (normalized to the SM values): C_{hgg}/SM=-0.92, C_{h\gamma\gamma}/SM=1.42 and C_{hZ\gamma}/SM=1.16.
View original: http://arxiv.org/abs/1303.2426

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