426 research outputs found
The gluon-fusion uncertainty in Higgs coupling extractions
We point out that the QCD corrections to the gluon-fusion Higgs boson
production cross section at the LHC are very similar to the corrections to the
Higgs decay rate into two gluons. Consequently, the ratio of these two
quantities has a theoretical uncertainty smaller than the uncertainty in the
cross section alone by a factor of two. We note that since this ratio is the
theoretical input to analyses of Higgs coupling extractions at the LHC, the
reduced uncertainty should be used; in previous studies, the full cross section
uncertainty was employed.Comment: 4 pages, 3 figure
NLO QCD corrections to the production of t-tbar-Z in gluon fusion
We compute the O(alpha_s) QCD corrections to the partonic process gg ->
t-tbar-Z at the LHC. This partonic channel is the dominant component of the
scattering process pp -> t-tbar-Z, which will be important for measuring the
t-tbar-Z electroweak couplings. The O(alpha_s) corrections increase the total
cross section by up to 75% for reasonable choices of the renormalization and
factorization scales. Inclusion of these contributions descreases the residual
scale dependence of the cross section coming from uncalculated higher order
terms to +-5%.Comment: 9 pages, 4 figure
Mixed QCD-electroweak corrections to Higgs boson production in gluon fusion
We compute the 3-loop O(\alpha \alpha_s) correction to the Higgs boson
production cross section arising from light quarks using an effective theory
approach. Our calculation probes the factorization of QCD and electroweak
perturbative corrections to this process. We combine our results with the best
current estimates for contributions from top and bottom quarks to derive an
updated theoretical prediction for the Higgs boson production cross section in
gluon fusion. With the use of the MSTW 2008 parton distribution functions that
include the newest experimental data, our study results in cross sections
approximately 4-6% lower for intermediate Higgs boson masses than those used in
recent Tevatron analyses that imposed a 95% confidence level exclusion limit of
a Standard Model Higgs boson with M_H=170 GeV.Comment: 16 pgs., 5 figs. References and discussion added. Numerical results
updated to use recent MSTW 2008 PDFs, which decrease the predicted Tevatron
cross sectio
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