Next-to-Next-to-Leading-Order Subtraction Formalism in Hadron Collisions and its Application to Higgs-Boson Production at the Large Hadron Collider

Abstract

We consider higher-order QCD corrections to the production of colourless highmass systems (lepton pairs, vector bosons, Higgs bosons, . . . ) in hadron collisions. We propose a new formulation of the subtraction method to numerically compute arbitrary infrared-safe observables for this class of processes. To cancel the infrared divergences, we exploit the universal behaviour of the associated transverse-momentum (q T ) distributions in the small-q T region. The method is illustrated in general terms up to the next-to-next-to-leading order (NNLO) in QCD perturbation theory. As a first explicit application, we study Higgs boson production through gluon fusion. Our calculation is implemented in a parton level Monte Carlo program that includes the decay of the Higgs boson in two photons. We present selected numerical results at the LHC.

Electroweak production of top-quark pairs ine+e−annihilation at NNLO in QCD: The vector current contributions

“…Inspired by the successful application of q T subtraction method of Catani and Grazzini [72], recently there has been some interest and progress in applying the phase-space slicing method to NNLO QCD calculations. For instance, top quark decay [99], Drell-Yan production [140], and Higgs production [141] have all been studied in schemes very similar to the one described in this work.…”

Two-loop splitting amplitudes and the single-real contribution to inclusive Higgs production at N3LO

“…At the same order, one-loop corrections to simple collinear [38] and simple soft [14] emissions need to be accounted for. The behaviour in all these limits is understood in detail, and served as a construction principle for subtraction methods at NNLO [15][16][17]. In an actual calculation of higher order corrections to a collider observable, the universal soft and collinear factors need to be integrated over their appropriate phase spaces, including a regulator for the infrared divergences.…”

Two-loop leading color corrections to heavy-quark pair production in the gluon fusion channel

“…Their implementation requires the application of a NNLO subtraction method. The methods presently available [53][54][55][56][57][58][59][60][61][62][63][64][65][66][67] do not provide yet the full counterterms for a 2 → 2 hadronic process involving massive partons. Two subtraction methods for the NNLO calculation of the top-quark pair production cross section were outlined recently [68,69].…”

“…The diagrams belonging to the sets ii) and iii) form part of the NLO corrections to top-pair-plus-jet production and have been calculated by several groups [49][50][51][52]. Aside from the calculation of the required Feynman diagrams, a full NNLO calculation of the top-quark pair production cross section is particularly challenging because it entails the development of a NNLO subtraction method, which could be used in processes with massive partons [53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69].…”