One-Loop Helicity Amplitudes for ttbar Production at Hadron Colliders

We present compact analytic expressions for all one-loop helicity amplitudes contributing to ttbar production at hadron colliders. Using recently developed generalised unitarity methods and a traditional Feynman based approach we produce a fast and flexible implementation.Comment: 29 pages, 5 figures, v2 typos corrected (journal version

Computation of multi-leg amplitudes with NJet

In these proceedings we report our progress in the development of the publicly available C++ library NJet for accurate calculations of high-multiplicity one-loop amplitudes. As a phenomenological application we present the first complete next-to-leading order (NLO) calculation of five jet cross section at hadron colliders.Comment: 8 pages, 5 figures, Contribution to the proceedings of "ACAT 2013" conference, Beijing, China, May 201

Three-loop master integrals for ladder-box diagrams with one massive leg

The three-loop master integrals for ladder-box diagrams with one massive leg are computed from an eighty-five by eighty-five system of differential equations, solved by means of Magnus exponential. The results of the considered box-type integrals, as well as of the tower of vertex- and bubble-type master integrals associated to subtopologies, are given as a Taylor series expansion in the dimensional regulator parameter epsilon = (4-d)/2. The coefficients of the series are expressed in terms of uniform weight combinations of multiple polylogarithms and transcendental constants up to weight six. The considered integrals enter the next-to-next-to-next-to-leading order virtual corrections to scattering processes like the three-jet production mediated by vector boson decay, V* -> jjj, as well as the Higgs plus one-jet production in gluon fusion, pp -> Hj.Comment: 44 pages, 5 figures, 2 ancillary file

Next-to-leading order QCD corrections to di-photon production in association with up to three jets at the Large Hadron Collider

We present the computation of next-to-leading order (NLO) QCD corrections to di-photon production in association with two or three hard jets in pp collisions at a centre-of-mass energy of 8 TeV. The inclusion of NLO corrections is shown to substantially reduce the theoretical uncertainties estimated from scale variations on total cross section predictions. We study a range of differential distributions relevant for phenomenological studies of photon pair production in association with jets at the LHC. Using an efficient computational set-up we performed a detailed study of uncertainties due to parton distribution functions. The computation of the virtual corrections is performed using new features of the C++ library NJet

Computation of multi-leg amplitudes with NJET

In these proceedings we report our progress in the development of the publicly available C++ library NJet for accurate calculations of high-multiplicity one-loop amplitudes. As a phenomenological application we present the first complete next-to-leading order (NLO) calculation of five jet cross section at hadron colliders.Peer Reviewe

recent progress in higher order computations for the physics of the higgs boson

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