Julien Baglio

Higgs production at the lHC

We analyze the production of Higgs particles at the early stage of the CERN large Hadron Collider with a 7 TeV center of mass energy (lHC). We first consider the case of the Standard Model Higgs boson that is mainly produced in the gluon-gluon fusion channel and to be detected in its decays into electroweak gauge bosons, gg → H → WW, ZZ, γγ. The production cross sections at

The apparent excess in the Higgs to di-photon rate at the LHC: New Physics or QCD uncertainties?

\sqrt {s} = 7\;{\text{TeV}}

Heavy neutrino impact on the triple Higgs coupling

and the decay branching ratios, including all relevant higher order QCD and electroweak corrections, are evaluated. An emphasis is put on the various theoretical uncertainties that affect the production rates: the significant uncertainties from scale variation and from the parametrization of the parton distribution functions as well as the uncertainties which arise due to the use of an effective field theory in the calculation of the next-to-next-to-leading order corrections. The parametric uncertainties stemming from the values of the strong coupling constant and the heavy quark masses in the Higgs decay branching ratios, which turn out to be non-negligible, are also discussed. The implications for different center of mass energies of the proton collider,

Next-To-Leading Order QCD Corrections to Associated Production of a SM Higgs Boson with a Pair of Weak Bosons in the POWHEG-BOX

\sqrt {s} = 8 - 10\;{\text{TeV}}

NLO QCD effective field theory analysis of W+W- production at the LHC including fermionic operators

as well as for the design energy

Impact of heavy sterile neutrinos on the triple Higgs coupling

\sqrt {s} = 14\;{\text{TeV}}

Gluon fusion and

, are briefly summarized. We then discuss the production of the neutral Higgs particles of the Minimal Supersymmetric extension of the Standard Model in the two main channels: gluon-gluon and bottom quark fusion leading to Higgs bosons which subsequently decay into tau lepton or b-quark pairs,

b\bar{b}

gg,b\bar{b} \to {\text{Higgs}} \to {\tau^{+} }{\tau^{-} },b\bar{b}

corrections to

. The Higgs production cross sections at the lHC and the decay branching ratios are analyzed. The associated theoretical uncertainties are found to be rather large and will have a significant impact on the parameter space of the model that can be probed.

H W^+ W^- / H Z Z

Abstract The Higgs boson with a mass M H ≈ 126 GeV has been observed by the ATLAS and CMS experiments at the LHC and a total significance of about five standard deviations has been reported by both collaborations when the channels H → γ γ and H → Z Z → 4 l are combined. Nevertheless, while the rates in the later search channel appear to be in accord with those predicted in the Standard Model, there seems to be an excess of data in the case of the H → γ γ discovery channel. Before invoking new physics contributions to explain this excess in the di-photon Higgs rate, one should verify that standard QCD effects cannot account for it. We describe how the theoretical uncertainties in the Higgs boson cross section for the main production process at the LHC, g g → H , which are known to be large, should be incorporated in practice. We further show that the discrepancy between the theoretical prediction and the measured value of the g g → H → γ γ rate, reduces to about one standard deviation when the QCD uncertainties are taken into account.