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Register a new userHiggs boson pair production in gluon fusion at NLO with full top-quark mass dependence
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We present the calculation of the cross section and invariant mass distribution for Higgs boson pair production in gluon fusion at next-to-leading order (NLO) in QCD. Top-quark masses are fully taken into account throughout the calculation. The virtual two-loop amplitude has been generated using an extension of the program GoSam supplemented with an interface to Reduze for the integral reduction. The occurring integrals have been calculated numerically using the program SecDec. Our results, including the full top-quark mass dependence for the first time, allow us to assess the validity of various approximations proposed in the literature, which we also recalculate. We find substantial deviations between the NLO result and the different approximations, which emphasizes the importance of including the full top-quark mass dependence at NLO.
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We present the first combination of NLO QCD matrix elements for di-Higgs production, retaining the full top quark mass dependence, with a parton shower. Results are provided within both the POWHEG-BOX and MadGraph5_aMC@NLO Monte Carlo frameworks. We assess in detail the theoretical uncertainties and provide differential results. We find that, as expected, the shower effects are relatively large for observables like the transverse momentum of the Higgs boson pair, which are sensitive to extra radiation. However, these shower effects are still much smaller than the differences between the Born-improved HEFT approximation and the full NLO calculation in the tails of the distributions.
We present the next-to-leading order QCD corrections to the production of a Higgs boson in association with one jet at the LHC including the full top-quark mass dependence. The mass of the bottom quark is neglected. The two-loop integrals appearing in the virtual contribution are calculated numerically using the method of Sector Decomposition. We study the Higgs boson transverse momentum distribution, focusing on the high $p_{t,mathrm{H}}$ region, where the top-quark loop is resolved. We find that the next-to-leading order QCD corrections are large but that the ratio of the next-to-leading order to leading order result is similar to that obtained by computing in the limit of large top-quark mass.
Higgs-pair production via gluon fusion is the dominant production mechanism of Higgs-boson pairs at hadron colliders. In this work, we present details of our numerical determination of the full next-to-leading-order (NLO) QCD corrections to the leading top-quark loops. Since gluon fusion is a loop-induced process at leading order, the NLO calculation requires the calculation of massive two-loop diagrams with up to four different mass/energy scales involved. With the current methods, this can only be done numerically, if no approximations are used. We discuss the setup and details of our numerical integration. This will be followed by a phenomenological analysis of the NLO corrections and their impact on the total cross section and the invariant Higgs-pair mass distribution. The last part of our work will be devoted to the determination of the residual theoretical uncertainties with special emphasis on the uncertainties originating from the scheme and scale dependence of the (virtual) top mass. The impact of the trilinear Higgs-coupling variation on the total cross section will be discussed.
In our work: 0903.2612, we calculate the production rate of single top-Higgs boson in the TC2 model which is a modified version of the original top-technicolor model. The similar process was discussed in arXiv:hep-ph/9905347v2. The TC2 model, as we discussed in the introduction part remedies some shortcomings and loophole of the old version. The top-Higgs in the TC2 model is a mixture of the top-Higgs of the toptechnicolor model and that of the ETC model, thus a parameter $epsilon$ is introduced to denote the mixture. Moreover, we vary the mass range of the top-Higgs within 300 to 800 GeV while in arXiv:hep-ph/9905347v2, the mass range was taken as 200 to 400 GeV. In the work, our numerical results show that the production rate of single top-Higgs in the TC2 model is very close to that in the toptecnicolor model within the mass range of 200 to 400 GeV. This manifests that change from the original toptechnicolor model to the new TC2 version does not much affect the production rate of the top-Higgs even though the two top-Higgs in the two models are different. Beyond the 400 GeV, even the TC2 model predicts a negligible production rate at LHC. Since the phenomenological change is indeed not obvious, there is not much new to report. Even though the two models are somehow different, we believe that the result is not worth publishing. Therefore we decide to withdraw our manuscript.
We discuss the calculation of charged Higgs boson production in association with top quark in the MC@NLO framework for combining NLO matrix elements with a parton shower. The process is defined in a model independent manner for wide applicability, and can be used if the charged Higgs boson mass is either greater or less than the mass of the top quark. For the latter mass region, care is needed in defining the charged Higgs production mode due to interference with top pair production. We give a suitable definition applicable in an NLO (plus parton shower) context, and present example results for the LHC.
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