39 research outputs found

    Antenna subtraction with massive fermions at NNLO: Double real initial-final configurations

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    We derive the integrated forms of specific initial-final tree-level four-parton antenna functions involving a massless initial-state parton and a massive final-state fermion as hard radiators. These antennae are needed in the subtraction terms required to evaluate the double real corrections to ttˉt\bar{t} hadronic production at the NNLO level stemming from the partonic processes qqˉ→ttˉq′qˉ′q\bar{q}\to t\bar{t}q'\bar{q}' and gg→ttˉqqˉgg\to t\bar{t}q\bar{q}.Comment: 24 pages, 1 figure, 1 Mathematica file attache

    NNLO corrections to top-pair production at hadron colliders: the all-fermionic scattering channels

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    This is a second paper in our ongoing calculation of the next-to-next-to-leading order (NNLO) QCD correction to the total inclusive top-pair production cross-section at hadron colliders. In this paper we calculate the reaction qqˉ→ttˉ+qqˉq\bar q \to t\bar t + q\bar q which was not considered in our previous work on qqˉ→ttˉ+Xq\bar q \to t\bar t +X due to its phenomenologically negligible size. We also calculate all remaining fermion-pair-initiated partonic channels qq′,qqˉ′qq', q\bar q' and qqqq that contribute to top-pair production starting from NNLO. The contributions of these reactions to the total cross-section for top-pair production at the Tevatron and LHC are small, at the permil level. The most interesting feature of these reactions is their characteristic logarithmic rise in the high energy limit. We compute the constant term in the leading power behavior in this limit, and achieve precision that is an order of magnitude better than the precision of a recent theoretical prediction for this constant. All four partonic reactions computed in this paper are included in our numerical program Top++. The calculation of the NNLO corrections to the two remaining partonic reactions, qg→ttˉ+Xqg\to t\bar t+X and gg→ttˉ+Xgg\to t\bar t+X, is ongoing.Comment: 1+16 pages; 3 figure

    The fully differential hadronic production of a Higgs boson via bottom quark fusion at NNLO

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    The fully differential computation of the hadronic production cross section of a Higgs boson via bottom quarks is presented at NNLO in QCD. Several differential distributions with their corresponding scale uncertainties are presented for the 8 TeV LHC. This is the first application of the method of non-linear mappings for NNLO differential calculations at hadron colliders.Comment: 27 pages, 13 figures, 1 lego plo

    Double real radiation corrections to ttˉt\bar{t} production at the LHC: the all-fermion processes

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    We present the double real radiation corrections to the hadronic ttˉt \bar{t} production stemming from partonic processes with fermions only. For this purpose, we extend the NNLO antenna subtraction formalism developed originally for the computation of jet observables in e+e−e^+e^- annihilation to include the evaluation of hadronic observables involving a massive pair of particles. In all partonic processes, we checked the validity of our subtraction terms given for leading and subleading colour contributions numerically by showing that the ratio between real radiation matrix elements and subtraction terms approaches unity in all single and double unresolved configurations.Comment: 68 pages, 9 figure

    Antenna subtraction at NNLO with hadronic initial states: double real initial-initial configurations

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    The antenna subtraction method handles real radiation contributions in higher order corrections to jet observables. The method is based on antenna functions, which encapsulate all unresolved radiation between a pair of hard radiator partons. To apply this method to compute hadron collider observables, initial-initial antenna functions with both radiators in the initial state are required in unintegrated and integrated forms. In view of extending the antenna subtraction method to next-to-next-to-leading order (NNLO) calculations at hadron colliders, we derive the full set of initial-initial double real radiation antenna functions in integrated form.Comment: 38 pages; a FORM file with the integrated antennae is included with this submission. arXiv admin note: text overlap with arXiv:1011.6631, arXiv:1107.403

    Antenna subtraction at NNLO with hadronic initial states: real-virtual initial-initial configurations

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    The antenna subtraction method handles real radiation contributions in higher order corrections to jet observables. The method is based on antenna functions, which encapsulate all unresolved radiation between a pair of hard radiator partons. To apply this method to compute hadron collider observables, initial-initial antenna functions with both radiators in the initial state are required. In view of extending the antenna subtraction method to next-to-next-to-leading order (NNLO) calculations at hadron colliders, we derive the one-loop initial-initial antenna functions in unintegrated and integrated form.Comment: 24 page

    The real radiation antenna function for S→QQˉqqˉS \to Q {\bar Q} q {\bar q} at NNLO QCD

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    As a first step towards the application of the antenna subtraction formalism to NNLO QCD reactions with massive quarks, we determine the real radiation antenna function and its integrated counterpart for reactions of the type S→QQˉqqˉS \to Q{\bar Q} q {\bar q}, where SS denotes an uncolored initial state and QQ, qq a massive and massless quark, respectively. We compute the corresponding integrated antenna function in terms of harmonic polylogarithms. As an application and check of our results we calculate the contribution proportional to αs2eQ2Nf\alpha_s^2 e^2_Q N_f to the inclusive heavy-quark pair production cross ection in e+e−e^+e^- annihilation.Comment: Latex, 32 page
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