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Related papers: Cutting massless four-loop propagators

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Recently, a new construction for complete loop integrands of massless field theories has been proposed, with on-shell tree-level amplitudes delicately incorporated into its algorithm. This new approach reinterprets integrands in a novel…

High Energy Physics - Theory · Physics 2016-04-28 Rijun Huang , Qingjun Jin , Junjie Rao , Kang Zhou , Bo Feng

We proposed a recipe to systematically calculate Feynman integrals containing linear propagators using the auxiliary mass flow method. The key of the recipe is to introduce a quadratic term for each linear propagator and then using…

High Energy Physics - Phenomenology · Physics 2023-01-30 Zhi-Feng Liu , Yan-Qing Ma

The massless one-loop box integral with arbitrary indices in arbitrary space-time dimension $d$ is shown to reduce to a sum over three generalised hypergeometric functions. This result follows from the solution to the third order…

High Energy Physics - Phenomenology · Physics 2017-09-25 O. V. Tarasov

We study several multiscale one-loop five-point families of Feynman integrals. More specifically, we employ the Simplified Differential Equations approach to obtain results in terms of Goncharov polylogarithms of up to transcendental weight…

High Energy Physics - Phenomenology · Physics 2021-09-14 Nikolaos Syrrakos

The standard unitarity-cut method is applied to several massive two-dimensional models, including the world-sheet AdS$_5\times S^5$ superstring, to compute $2\to 2$ scattering S-matrices at one loop from tree level amplitudes. Evidence is…

High Energy Physics - Theory · Physics 2014-01-03 Valentina Forini , Lorenzo Bianchi , Ben Hoare

We determine the master integrals for vertex and propagator diagrams that appear in effective field theories containing heavy fields. The integrals involve at least one heavy line, and the standard lines include an arbitrary mass scale. The…

High Energy Physics - Phenomenology · Physics 2022-01-19 B. Assi , B. A. Kniehl , A. I. Onishchenko

We describe the analytic continuation of two-loop four-point functions with one off-shell external leg and internal massless propagators from the Euclidean region of space-like $1\to 3$ decay to Minkowskian regions relevant to all $1\to 3$…

High Energy Physics - Phenomenology · Physics 2010-04-05 T. Gehrmann , E. Remiddi

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/epsilon^6. The computational techniques involve, among others,…

High Energy Physics - Phenomenology · Physics 2010-01-20 T. Huber

We evaluate three typical four-loop non-planar massless propagator diagrams in a Taylor expansion in dimensional regularization parameter $\epsilon=(4-d)/2$ up to transcendentality weight twelve, using a recently developed method of one of…

High Energy Physics - Theory · Physics 2011-08-17 R. N. Lee , A. V. Smirnov , V. A. Smirnov

We present the calculation of massless two-loop Master Integrals relevant to five-point amplitudes with one off-shell external leg and derive the complete set of planar Master Integrals with five on-mass-shell legs, that contribute to many…

High Energy Physics - Phenomenology · Physics 2016-05-04 Costas G. Papadopoulos , Damiano Tommasini , Christopher Wever

We present the analytic calculation of the Master Integrals for the two-loop, non-planar topologies that enter the calculation of the amplitude for top-quark pair hadroproduction in the quark-annihilation channel. Using the method of…

High Energy Physics - Phenomenology · Physics 2019-09-04 Matteo Becchetti , Roberto Bonciani , Valerio Casconi , Andrea Ferroglia , Simone Lavacca , Andreas von Manteuffel

We improve on Cutkosky's cutting rules which is used to calculate the contribution of the singularities of Feynman propagators to Feynman amplitude. The correctness of the improved cutting rules is verified by the calculations of the…

High Energy Physics - Phenomenology · Physics 2010-05-21 Yong Zhou

We describe the application of a novel approach for the reduction of scattering amplitudes, based on multivariate polynomial division, which we have recently presented. This technique yields the complete integrand decomposition for…

High Energy Physics - Phenomenology · Physics 2013-07-17 Pierpaolo Mastrolia , Edoardo Mirabella , Giovanni Ossola , Tiziano Peraro

We develop a new way to analytically calculate loop integrals in the Effective Field Theory of Large Scale-Structure. Previous available methods show severe limitations beyond the one-loop power spectrum due to analytical challenges and…

Cosmology and Nongalactic Astrophysics · Physics 2023-05-15 Charalampos Anastasiou , Diogo P. L. Bragança , Leonardo Senatore , Henry Zheng

We compute the master integrals containing one massive propagator entering the two-loop electroweak form factor, i.e. the process f fbar --> X, where f fbar is an on-shell massless fermion pair and X is a singlet particle under SU(2)L x…

High Energy Physics - Phenomenology · Physics 2009-11-10 U. Aglietti , R. Bonciani

We propose a new set of Master Integrals which can be used as a basis for certain multiloop calculations in massless gauge field theories. In these theories we consider three-point Feynman diagrams with arbitrary number of loops. The…

High Energy Physics - Theory · Physics 2016-11-29 Julio Borja , Igor Kondrashuk

Using unitarity methods, we compute, for several massive two-dimensional models, the cut-constructible part of the one-loop 2->2 scattering S-matrices from the tree-level amplitudes. We apply our method to various integrable theories,…

High Energy Physics - Theory · Physics 2015-06-15 Lorenzo Bianchi , Valentina Forini , Ben Hoare

We present an ansatz for the planar five-loop four-point amplitude in maximally supersymmetric Yang-Mills theory in terms of loop integrals. This ansatz exploits the recently observed correspondence between integrals with simple conformal…

High Energy Physics - Theory · Physics 2008-11-26 Z. Bern , J. J. M. Carrasco , H. Johansson , D. A. Kosower

We discuss the extension of the maximal-unitarity method to two loops, focusing on the example of the planar double box. Maximal cuts are reinterpreted as contour integrals, with the choice of contour fixed by the requirement that integrals…

High Energy Physics - Theory · Physics 2012-12-11 Henrik Johansson , David A. Kosower , Kasper J. Larsen

We present analytical expressions for the 31 five-particle phase-space master integrals in massless QCD as an $\epsilon$-series with coefficients being multiple zeta values of weight up to 12. In addition, we provide computer code for the…

High Energy Physics - Phenomenology · Physics 2018-08-01 O. Gituliar , V. Magerya , A. Pikelner