NNLL resummation for the associated production of a top pair and a Higgs boson at the LHC

Broggio, Alessandro; Ferroglia, Andrea; Pecjak, Ben D.; Yang, Li Lin

doi:10.1007/jhep02(2017)126

Cited by 52 publications

(94 citation statements)

References 44 publications

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“…This approach was adopted in [31] for top-pair production. Subsequently, it was also applied to the evaluation of the soft emission corrections to ttW ± [41], ttH [42], and ttZ [43] to NNLL accuracy. The starting point is the factorization of the partonic cross section in the soft limit.…”

Section: Resummation In the Soft Limitmentioning

confidence: 99%

Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCD

Czakon

Ferroglia

Heymes

et al. 2018

J. High Energ. Phys.

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We construct predictions for top quark pair differential distributions at hadron colliders that combine state-of-the-art NNLO QCD calculations with double resummation at NNLL accuracy of threshold logarithms arising from soft gluon emissions and of small mass logarithms. This is the first time a resummed calculation at full NNLO+NNLL accuracy in QCD for a process with non-trivial color structure has been completed at the differential level. Of main interest to us is the stability of the M tt and top-quark p T distributions in the boosted regime where fixed order calculations may become strongly dependent JHEP05 (2018)149 on the choice of dynamic scales. With the help of numeric and analytic arguments we confirm that the choice for the factorization and renormalization scales advocated recently by some of the authors is indeed optimal. We further derive a set of optimized kinematicsdependent scales for the matching functions which appear in the resummed calculations. Our NNLO+NNLL prediction for the top-pair invariant mass is significantly less sensitive to the choice of factorization scale than the fixed order prediction, even at NNLO. Notably, the resummed and fixed order calculations are in nearly perfect agreement with each other in the full M tt range when the optimal dynamic scale is used. For the top-quark p T distribution the resummation performed here has less of an impact and instead we find that upgrading the matching with fixed-order from NLO+NNLL to NNLO+NNLL to be an important effect, a point to be kept in mind when using NLO-based Monte Carlo event generators to calculate this distribution.

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Section: Resummation In the Soft Limitmentioning

confidence: 99%

Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCD

Czakon

Ferroglia

Heymes

et al. 2018

J. High Energ. Phys.

Self Cite

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“…This is relevant to the production processes of top quark pairs associated with a Higgs boson or an electroweak gauge boson. At the NLO, the general result of [33] can be utilized, and has been successfully applied to ttH production in [63,64], to ttW production in [91,92], and to ttZ production in [93]. It remains open whether a similar general result can be derived at the NNLO, which we leave for future work.…”

Section: Jhep06(2018)013mentioning

confidence: 98%

“…In fact, since the NLO soft function involves 2-parton correlations at most, the same calculation can be applied to scattering processes with more than two colored particles in the final state. This has been done, e.g., for the case of ttH production in [63,64], and can be extended to more complicated processes such the simultaneous production of two tt pairs. In order to calculate the NNLO soft…”

Section: Jhep06(2018)013mentioning

confidence: 99%

“…While the formalism can be applied to any reference frame, in the following, we will work in the center-of-mass frame of the two incoming partons, which are not only good for demonstration purposes, and are also adopted in many existing calculations. For example, this corresponds to the PIM kinematics in [33,59,60] for tt production, in [61,62] for stop pair production, and in [63,64] for ttH production. Schematically, we are considering partonic processes of the form…”

Section: Jhep06(2018)013mentioning

confidence: 99%

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The next-to-next-to-leading order soft function for top quark pair production

Wang

Yang

et al. 2018

J. High Energ. Phys.

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We present the first calculation of the next-to-next-to-leading order threshold soft function for top quark pair production at hadron colliders, with full velocity dependence of the massive top quarks. Our results are fully analytic, and can be entirely written in terms of generalized polylogarithms. The scale-dependence of our result coincides with the well-known two-loop anomalous dimension matrix including the three-parton correlations, which at the two-loop order only appear when more than one massive partons are involved in the scattering process. In the boosted limit, our result exhibits the expected factorization property of mass logarithms, which leads to a consistent extraction of the soft fragmentation function. The next-to-next-to-leading order soft function obtained in this paper is an important ingredient for threshold resummation at the next-to-next-to-nextto-leading logarithmic accuracy.

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“…The precise evaluation of the total production cross section to the highest order in QCD is of crucial importance to study this rare process at the LHC. The impact of soft gluon resummation to next-tonext-to-leading logarithmic (NNLL) accuracy is already available [11,12].…”

Section: Introductionmentioning

confidence: 99%

CP tests of Higgs couplings in tt¯h semileptonic events at the LHC

2018

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The CP nature of the Higgs coupling to top quarks is addressed in this paper, in single charged lepton final states of tth events produced in proton-proton collisions at the LHC. Pure scalar (h ¼ H) and pseudoscalar (h ¼ A) Higgs boson signal events, generated with MADGRAPH5_AMC@NLO, are fully reconstructed using a kinematic fit. Angular distributions of the decay products, as well as CP-sensitive asymmetries, are exploited to separate and gain sensitivity to possible pseudoscalar components of the Higgs boson and reduce the contribution from the dominant irreducible background ttbb. Significant differences are found between the pure CP-even and -odd signal hypotheses as well as with respect to the Standard Model background, in particular the ttbb contribution. Such differences survive the event reconstruction, allowing one to define optimal observables to extract the Higgs couplings parameters from a global fit. A dedicated analysis is applied to efficiently identify signal events and reject as much as possible the expected Standard Model background. The results obtained are compared with a similar analysis in the dilepton channel. We show that the single lepton channel is more promising overall and can be used in combination to study the CP nature of the Higgs coupling to top quarks.

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NNLL resummation for the associated production of a top pair and a Higgs boson at the LHC

Cited by 52 publications

References 44 publications

Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCD

Resummation for (boosted) top-quark pair production at NNLO+NNLL′ in QCD

The next-to-next-to-leading order soft function for top quark pair production

CP tests of Higgs couplings in tt¯h semileptonic events at the LHC

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