The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform
Matthias Steinhauser - One of the best experts on this subject based on the ideXlab platform.
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Three-Loop Form factors for Higgs boson pair production in the large top mass limit
Journal of High Energy Physics, 2019Co-Authors: Joshua Davies, Matthias SteinhauserAbstract:We consider the virtual corrections to Higgs boson pair production at next-to- next-to-leading order, in the large top quark mass limit. We compute five expansion terms for the box-type Form factors and eight expansion terms for the triangle Form factor, which serve as useful input for the construction of approximations. We present analytic results for the Form factors in the soft-virtual approximation. From a technical point of view the calculation is quite challenging since huge intermediate expressions are produced. We describe our methods and optimizations to overcome these difficulties, which might be useful for other calculations.
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Massive quark Form factors
Proceedings of Loops and Legs in Quantum Field Theory — PoS(LL2018), 2018Co-Authors: Roman N. Lee, Vladimir A Smirnov, Alexander V Smirnov, Matthias SteinhauserAbstract:In this contribution we provide further details to the recent calculation of QCD corrections to massive three-Loop Form factors presented in Ref.~\cite{Lee:2018rgs}.
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Massive quark Form factors
arXiv: High Energy Physics - Phenomenology, 2018Co-Authors: Roman N. Lee, Vladimir A Smirnov, Alexander V Smirnov, Matthias SteinhauserAbstract:In this contribution we provide further details to the recent calculation of QCD corrections to massive three-Loop Form factors presented in Ref. [1].
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The $n_f^2$ contributions to fermionic four-Loop Form factors
Physical Review D, 2017Co-Authors: Roman N. Lee, Vladimir A Smirnov, Alexander V Smirnov, Matthias SteinhauserAbstract:We compute the four-Loop contributions to the photon quark and Higgs quark Form factors involving two closed fermion Loops. We present analytical results for all non-planar master integrals of the two non-planar integral families which enter our calculation.
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High energy behaviour of Form factors
Journal of High Energy Physics, 2017Co-Authors: Taushif Ahmed, Johannes M. Henn, Matthias SteinhauserAbstract:We solve renormalization group equations that govern infrared divergences of massless and massive Form factors. By comparing to recent results for planar massive three-Loop and massless four-Loop Form factors in QCD, we give predictions for the high-energy limit of massive Form factors at the four- and for the massless Form factor at five-Loop order. Furthermore, we discuss the relation which connects infrared divergences regularized dimensionally and via a small quark mass and extend results present in the literature to higher order.
E. Sokatchev - One of the best experts on this subject based on the ideXlab platform.
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wilson Loop Form factors a new duality
Journal of High Energy Physics, 2018Co-Authors: D. Chicherin, G. Korchemsky, P. Heslop, E. SokatchevAbstract:We find a new duality for Form factors of lightlike Wilson Loops in planar $$ \mathcal{N} $$ = 4 super-Yang-Mills theory. The duality maps a Form factor involving an n-sided lightlike polygonal super-Wilson Loop together with m external on-shell states, to the same type of object but with the edges of the Wilson Loop and the external states swapping roles. This relation can essentially be seen graphically in Lorentz harmonic chiral (LHC) superspace where it is equivalent to planar graph duality. However there are some crucial subtleties with the cancellation of spurious poles due to gauge fixing. They are resolved by finding the correct Formulation of the Wilson Loop and by careful analytic continuation from Minkowski to Euclidean space. We illustrate all of these subtleties explicitly in the simplest non-trivial NMHV-like case.
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Wilson Loop Form Factors: A New Duality
Journal of High Energy Physics, 2018Co-Authors: D. Chicherin, G. Korchemsky, P. Heslop, E. SokatchevAbstract:We find a new duality for Form factors of lightlike Wilson Loops in planar$\mathcal N=4$ super-Yang-Mills theory. The duality maps a Form factorinvolving an $n$-sided lightlike polygonal super-Wilson Loop together with $m$external on-shell states, to the same type of object but with the edges of theWilson Loop and the external states swapping roles. This relation canessentially be seen graphically in Lorentz harmonic chiral (LHC) superspacewhere it is equivalent to planar graph duality. However there are some crucialsubtleties with the cancellation of spurious poles due to the gauge fixing.They are resolved by finding the correct Formulation of the Wilson Loop and bycareful analytic continuation from Minkowski to Euclidean space. We illustrateall of these subtleties explicitly in the simplest non-trivial NMHV-like case.
Tobias Huber - One of the best experts on this subject based on the ideXlab platform.
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The three-Loop Form factor in N=4 super Yang-Mills
Journal of High Energy Physics, 2012Co-Authors: Thomas Gehrmann, Johannes M. Henn, Tobias HuberAbstract:In this paper we study the Sudakov Form factor in N=4 super Yang-Mills theory to the three-Loop order. The latter is expressed in terms of planar and non-planar Loop integrals. We show that it is possible to choose a representation in which each Loop integral has uniForm transcendentality. We verify analytically the expected exponentiation of the infrared divergences with the correct values of the three-Loop cusp and collinear anomalous dimensions in dimensional regularisation. We find that the Form factor in N=4 super Yang-Mills can be related to the leading transcendentality part of the quark and gluon Form factors in QCD. We also study the ultraviolet properties of the Form factor in D>4 dimensions, and find unexpected cancellations, resulting in an improved ultraviolet behaviour.
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The quark and gluon Form factors to three Loops in QCD through to \mathcal{O}\left( {{\epsilon^2}} \right)
Journal of High Energy Physics, 2010Co-Authors: Thomas Gehrmann, Tobias Huber, E. W. N. Glover, N. Ikizlerli, C. StuderusAbstract:We give explicit Formulae for the O(ǫ) and O(ǫ 2 ) contributions to the unrenor- malised three Loop QCD corrections to quark and gluon Form factors. These contributions have at most transcendentality weight eight. The O(ǫ) terms of the three-Loop Form fac- tors are required for the extraction of the four-Loop quark and gluon collinear anomalous dimensions. The O(ǫ 2 ) terms represent an irreducible contribution to the finite part of the Form factors at four-Loops. For the sake of completeness, we also give the contributions to the one and two Loop Form factors to the same transcendentality weight eight.
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calculation of the quark and gluon Form factors to three Loops in qcd
Journal of High Energy Physics, 2010Co-Authors: T Gehrmann, Tobias Huber, E. W. N. Glover, N. Ikizlerli, C. StuderusAbstract:We describe the calculation of the three-Loop QCD corrections to quark and gluon Form factors. The relevant three-Loop Feynman diagrams are evaluated and the resulting three-Loop Feynman integrals are reduced to a small set of known master integrals by using integration-by-parts relations. Our calculation confirms the recent results by Baikov et al. for the three-Loop Form factors. In addition, we derive the subleading \( \mathcal{O}\left( \varepsilon \right) \) terms for the fermion-Loop type contributions to the three-Loop Form factors which are required for the extraction of the fermionic contributions to the four-Loop quark and gluon collinear anomalous dimensions. The finite parts of the Form factors are used to determine the hard matching coefficients for the Drell-Yan process and inclusive Higgs-production in soft-collinear effective theory.
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calculation of the quark and gluon Form factors to three Loops in qcd
arXiv: High Energy Physics - Phenomenology, 2010Co-Authors: T Gehrmann, Tobias Huber, E. W. N. Glover, N. Ikizlerli, C. StuderusAbstract:We describe the calculation of the three-Loop QCD corrections to quark and gluon Form factors. The relevant three-Loop Feynman diagrams are evaluated and the resulting three-Loop Feynman integrals are reduced to a small set of known master integrals by using integration-by-parts relations. Our calculation confirms the recent results by Baikov et al.\ for the three-Loop Form factors. In addition, we derive the subleading ${\cal O}(\e)$ terms for the fermion-Loop type contributions to the three-Loop Form factors which are required for the extraction of the fermionic contributions to the four-Loop quark and gluon collinear anomalous dimensions. The finite parts of the Form factors are used to determine the hard matching coefficients for the Drell-Yan process and inclusive Higgs-production in soft-collinear effective theory.
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Master integrals for massless three-Loop Form factors
Proceedings of RADCOR 2009 - 9th International Symposium on Radiative Corrections (Applications of Quantum Field Theory to Phenomenology) — PoS(RADCOR, 2010Co-Authors: Tobias HuberAbstract:We summarize the results for the master integrals of the three-Loop quark and gluon Form factor in massless QCD. Working in dimensional regularization we extract poles up to 1/e 6 . The computational techniques involve, among others, the expansion of higher transcendental functions and the Mellin-Barnes method. The coefficients of the Lauren t expansion in e are given either analytically or numerically to high precision.
Vladimir A Smirnov - One of the best experts on this subject based on the ideXlab platform.
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Massive quark Form factors
Proceedings of Loops and Legs in Quantum Field Theory — PoS(LL2018), 2018Co-Authors: Roman N. Lee, Vladimir A Smirnov, Alexander V Smirnov, Matthias SteinhauserAbstract:In this contribution we provide further details to the recent calculation of QCD corrections to massive three-Loop Form factors presented in Ref.~\cite{Lee:2018rgs}.
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Massive quark Form factors
arXiv: High Energy Physics - Phenomenology, 2018Co-Authors: Roman N. Lee, Vladimir A Smirnov, Alexander V Smirnov, Matthias SteinhauserAbstract:In this contribution we provide further details to the recent calculation of QCD corrections to massive three-Loop Form factors presented in Ref. [1].
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The $n_f^2$ contributions to fermionic four-Loop Form factors
Physical Review D, 2017Co-Authors: Roman N. Lee, Vladimir A Smirnov, Alexander V Smirnov, Matthias SteinhauserAbstract:We compute the four-Loop contributions to the photon quark and Higgs quark Form factors involving two closed fermion Loops. We present analytical results for all non-planar master integrals of the two non-planar integral families which enter our calculation.
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Massive three-Loop Form factor in the planar limit
Journal of High Energy Physics, 2017Co-Authors: Johannes M. Henn, Alexander V Smirnov, Vladimir A Smirnov, Matthias SteinhauserAbstract:We compute the three-Loop QCD corrections to the massive quark-anti-quark-photon Form factors F 1 and F 2 in the large-N c limit. The analytic results are expressed in terms of Goncharov polylogarithms. This allows for a straightforward numerical evaluation. We also derive series expansions, including power suppressed terms, for three kinematic regions corresponding to small and large invariant masses of the photon momentum, and small velocities of the heavy quarks.
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A planar four-Loop Form factor and cusp anomalous dimension in QCD
Journal of High Energy Physics, 2016Co-Authors: Johannes M. Henn, Alexander V Smirnov, Vladimir A Smirnov, Matthias SteinhauserAbstract:We compute the fermionic contribution to the photon-quark Form factor to four-Loop order in QCD in the planar limit in analytic Form. From the divergent part of the latter the cusp and collinear anomalous dimensions are extracted. Results are also presented for the finite contribution. We briefly describe our method to compute all planar master integrals at four-Loop order.
Johannes M. Henn - One of the best experts on this subject based on the ideXlab platform.
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High energy behaviour of Form factors
Journal of High Energy Physics, 2017Co-Authors: Taushif Ahmed, Johannes M. Henn, Matthias SteinhauserAbstract:We solve renormalization group equations that govern infrared divergences of massless and massive Form factors. By comparing to recent results for planar massive three-Loop and massless four-Loop Form factors in QCD, we give predictions for the high-energy limit of massive Form factors at the four- and for the massless Form factor at five-Loop order. Furthermore, we discuss the relation which connects infrared divergences regularized dimensionally and via a small quark mass and extend results present in the literature to higher order.
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Massive three-Loop Form factor in the planar limit
Journal of High Energy Physics, 2017Co-Authors: Johannes M. Henn, Alexander V Smirnov, Vladimir A Smirnov, Matthias SteinhauserAbstract:We compute the three-Loop QCD corrections to the massive quark-anti-quark-photon Form factors F 1 and F 2 in the large-N c limit. The analytic results are expressed in terms of Goncharov polylogarithms. This allows for a straightforward numerical evaluation. We also derive series expansions, including power suppressed terms, for three kinematic regions corresponding to small and large invariant masses of the photon momentum, and small velocities of the heavy quarks.
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A planar four-Loop Form factor and cusp anomalous dimension in QCD
Journal of High Energy Physics, 2016Co-Authors: Johannes M. Henn, Alexander V Smirnov, Vladimir A Smirnov, Matthias SteinhauserAbstract:We compute the fermionic contribution to the photon-quark Form factor to four-Loop order in QCD in the planar limit in analytic Form. From the divergent part of the latter the cusp and collinear anomalous dimensions are extracted. Results are also presented for the finite contribution. We briefly describe our method to compute all planar master integrals at four-Loop order.
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The three-Loop Form factor in N=4 super Yang-Mills
Journal of High Energy Physics, 2012Co-Authors: Thomas Gehrmann, Johannes M. Henn, Tobias HuberAbstract:In this paper we study the Sudakov Form factor in N=4 super Yang-Mills theory to the three-Loop order. The latter is expressed in terms of planar and non-planar Loop integrals. We show that it is possible to choose a representation in which each Loop integral has uniForm transcendentality. We verify analytically the expected exponentiation of the infrared divergences with the correct values of the three-Loop cusp and collinear anomalous dimensions in dimensional regularisation. We find that the Form factor in N=4 super Yang-Mills can be related to the leading transcendentality part of the quark and gluon Form factors in QCD. We also study the ultraviolet properties of the Form factor in D>4 dimensions, and find unexpected cancellations, resulting in an improved ultraviolet behaviour.
