Showing papers by "Pierpaolo Mastrolia published in 2014"
Posted Content•
TL;DR: The proceedings of the 2013 Les Houches workshop on physics at TeV colliders as discussed by the authors dealt primarily with the techniques for calculating standard model multi-leg NLO and NNLO QCD and NLO EW cross sections and comparison of those cross sections with LHC data from Run 1, and projections for future measurements in Run 2.
Abstract: This Report summarizes the proceedings of the 2013 Les Houches workshop on Physics at TeV Colliders. Session 1 dealt primarily with (1) the techniques for calculating standard model multi-leg NLO and NNLO QCD and NLO EW cross sections and (2) the comparison of those cross sections with LHC data from Run 1, and projections for future measurements in Run 2.
343 citations
TL;DR: GoSam as mentioned in this paper is a package for the automated calculation of one-loop amplitudes, which can be used for Monte Carlo programs with QCD and/or electroweak corrections to multi-particle processes.
Abstract: We present the version 2.0 of the program package GoSam for the automated calculation of one-loop amplitudes. GoSam is devised to compute one-loop QCD and/or electroweak corrections to multi-particle processes within and beyond the Standard Model. The new code contains improvements in the generation and in the reduction of the amplitudes, performs better in computing time and numerical accuracy, and has an extended range of applicability. The extended version of the “Binoth-Les-Houches-Accord” interface to Monte Carlo programs is also implemented. We give a detailed description of installation and usage of the code, and illustrate the new features in dedicated examples.
246 citations
TL;DR: GoSam as discussed by the authors is a package for the automated calculation of one-loop amplitudes, which can be used to compute oneloop QCD and/or electroweak corrections to multi-particle processes within and beyond the Standard Model.
Abstract: We present the version 2.0 of the program package GoSam for the automated calculation of one-loop amplitudes. GoSam is devised to compute one-loop QCD and/or electroweak corrections to multi-particle processes within and beyond the Standard Model. The new code contains improvements in the generation and in the reduction of the amplitudes, performs better in computing time and numerical accuracy, and has an extended range of applicability. The extended version of the "Binoth-Les-Houches-Accord" interface to Monte Carlo programs is also implemented. We give a detailed description of installation and usage of the code, and illustrate the new features in dedicated examples.
173 citations
TL;DR: In this article, the authors focus on systems of equations for Feynman integrals having a linear dependence on the dimensional parameter, and identify the criteria to bring them in a canonical form, where the dependence of the dimensional parameters is disentangled from the kinematics.
Abstract: We elaborate on the method of differential equations for evaluating Feynman integrals. We focus on systems of equations for master integrals having a linear dependence on the dimensional parameter. For these systems we identify the criteria to bring them in a canonical form, recently identified by Henn, where the dependence of the dimensional parameter is disentangled from the kinematics. The determination of the transformation and the computation of the solution are obtained by using Magnus and Dyson series expansion. We apply the method to planar and non-planar two-loop QED vertex diagrams for massive fermions, and to non-planar two-loop integrals contributing to 2 → 2 scattering of massless particles. The extension to systems which are polynomial in the dimensional parameter is discussed as well.
155 citations
TL;DR: In this article, a pure four-dimensional formulation (FDF) of the d-dimensional regularization of one-loop scaling amplitudes has been proposed, which allows for recursive construction of D-LOP integrands, generalizing the 4D open-loop approach.
Abstract: Elaborating on the four-dimensional helicity scheme, we propose a pure four-dimensional formulation (FDF) of the d-dimensional regularization of one-loop scat- tering amplitudes. In our formulation particles propagating inside the loop are represented by massive internal states regulating the divergences. The latter obey Feynman rules containing multiplicative selection rules which automati- cally account for the effects of the extra-dimensional reg- ulating terms of the amplitude. We present explicit rep- resentations of the polarization and helicity states of the four-dimensional particles propagating in the loop. They allow for a complete, four-dimensional, unitarity-based con- struction of d-dimensional amplitudes. Generalized unitar- ity within the FDF does not require any higher-dimensional extension of the Clifford and the spinor algebra. Finally we show how the FDF allows for the recursive construction of d-dimensional one-loop integrands, generalizing the four- dimensional open-loop approach.
67 citations
Posted Content•
TL;DR: In this paper, a pure four-dimensional formulation (FDF) of the d-dimensional regularization of one-loop scattering amplitudes is proposed, where particles propagating inside the loop are represented by massive internal states regulating the divergences.
Abstract: We propose a pure four-dimensional formulation (FDF) of the d-dimensional regularization of one-loop scattering amplitudes. In our formulation particles propagating inside the loop are represented by massive internal states regulating the divergences. The latter obey Feynman rules containing multiplicative selection rules which automatically account for the effects of the extra-dimensional regulating terms of the amplitude. The equivalence between the FDF and the Four Dimensional Helicity scheme is discussed. We present explicit representations of the polarization and helicity states of the four-dimensional particles propagating in the loop. They allow for a complete, four-dimensional, unitarity-based construction of d-dimensional amplitudes. Generalized unitarity within the FDF does not require any higher-dimensional extension of the Clifford and the spinor algebra. Finally we show how the FDF allows for the recursive construction of $d$-dimensional one-loop integrands, generalizing the four-dimensional open-loop approach.
44 citations
TL;DR: In this paper, the authors focus on systems of equations for Feynman integrals having a linear dependence on the dimensional parameter and identify the criteria to bring them in a canonical form, where the dependence of the dimension is disentangled from the kinematics.
Abstract: We elaborate on the method of differential equations for evaluating Feynman integrals. We focus on systems of equations for master integrals having a linear dependence on the dimensional parameter. For these systems we identify the criteria to bring them in a canonical form, recently identified by Henn, where the dependence of the dimensional parameter is disentangled from the kinematics. The determination of the transformation and the computation of the solution are obtained by using Magnus and Dyson series expansion. We apply the method to planar and non-planar two-loop QED vertex diagrams for massive fermions, and to non-planar two-loop integrals contributing to 2 -> 2 scattering of massless particles. The extension to systems which are polynomial in the dimensional parameter is discussed as well.
22 citations
18 Mar 2014
TL;DR: In this article, the main features of the GoSam framework for automated one-loop calculations are reviewed and a selection of recent phenomenological results obtained with it is presented, focusing on the recent calculation of NLO QCD corrections to the production of a Higgs boson in conjunction with jets at the LHC.
Abstract: After reviewing the main features of the GoSam framework for automated one-loop calculations, we present a selection of recent phenomenological results obtained with it. In particular, we focus on the recent calculation of NLO QCD corrections to the production of a Higgs boson in conjunction with jets at the LHC.
2 citations
20 Aug 2014
2 citations
25 Mar 2014
TL;DR: GoSam as discussed by the authors is a code-writer for automated one-loop calculations with a selection of phenomenological results recently obtained, giving relevance at the evaluation of NLO QCD corrections to the production of a Higgs boson in association with jets and heavy quarks.
Abstract: We elaborate on GoSam, a code-writer for automated one-loop calculations. After recalling its main features, we present a selection of phenomenological results recently obtained, giving relevance at the evaluation of NLO QCD corrections to the production of a Higgs boson in association with jets and heavy quarks.