Article

# The NNLO gluon fusion Higgs production cross-section with many heavy quark

(Impact Factor: 6.11). 03/2010; 2010(6):1-15. DOI: 10.1007/JHEP06(2010)101
Source: arXiv

ABSTRACT

We consider extensions of the Standard Model with a number of additional heavy quarks which couple to the Higgs boson via
top-like Yukawa interactions. We construct an effective theory valid for a Higgs boson mass which is lighter than twice the
lightest heavy quark mass and compute the corresponding Wilson coefficient through NNLO. We present numerical results for
the gluon fusion cross-section at the Tevatron for an extension of the Standard Model with a fourth generation of heavy quarks.
The gluon fusion cross-section at NLO and in the approximation of infinitely heavy quarks is enhanced by a factor of 9 with
respect to the Standard Model value. Tevatron experimental data can place stringent exclusion limits for the Higgs mass in
this model. We find that the relative magnitude of the higher order QCD corrections with respect to the LO is similar to the
Standard Model. Our result serves to carry out an exclusion analysis for a four-generation Standard Model with the same accuracy
as in the Standard Model analysis.

KeywordsHiggs Physics-NLO Computations

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Available from: Elisabetta Furlan, Feb 06, 2015
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• "However, since the observed Higgs candidate particle is produced at roughly the Standard Model rate, extensions of the Higgs sector beyond the Standard Model are extremely constrained. For example, a model with a sequential fourth generation of chiral fermions predicts large deviations in the Higgs rates [16] [17] [18] [19] [20] and is excluded by the limits on Higgs production for any Higgs mass below around 600 GeV [21] [22]. The properties of these potential new colored particles are further limited by precision electroweak measurements. "
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