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Related papers: BCJ Relations for One-Loop QCD Integral Coefficien…

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We formulate new integration rules for one-loop scattering equations analogous to those at tree-level, and test them in a number of non-trivial cases for amplitudes in scalar $\phi^3$-theory. This formalism greatly facilitates the…

High Energy Physics - Theory · Physics 2016-01-20 Christian Baadsgaard , N. E. J. Bjerrum-Bohr , Jacob L. Bourjaily , Poul H. Damgaard , Bo Feng

We present the two-loop helicity amplitudes for the scattering of massless quarks and massless gauge bosons in QCD. We use projector techniques to compute the coefficients of the general tensor describing the two-quark two-boson amplitude…

High Energy Physics - Phenomenology · Physics 2010-02-03 E. W. N. Glover , M. E. Tejeda-Yeomans

We present a computation of the one-loop QCD corrections to top-quark pair production in association with a $W$ boson, including terms up to order $\varepsilon^2$ in dimensional regularization. Providing a first glimpse into the complexity…

High Energy Physics - Phenomenology · Physics 2025-11-05 Matteo Becchetti , Maximilian Delto , Sara Ditsch , Philipp Alexander Kreer , Mattia Pozzoli , Lorenzo Tancredi

In this talk, the program package GOSAM is presented, which can be used for the automated calculation of one-loop amplitudes for multi-particle processes. The integrands are generated in terms of Feynman diagrams and can be reduced by…

High Energy Physics - Phenomenology · Physics 2012-01-19 G. Cullen , N. Greiner , G. Heinrich , G. Luisoni , P. Mastrolia , G. Ossola , T. Reiter , F. Tramontano

In this paper, we give the general expressions for a special series of tree amplitudes of the Yang-Mills theory. This series of amplitudes have two adjacent massless spin-1 particles with extra-dimensional momenta and any number of positive…

High Energy Physics - Theory · Physics 2019-10-08 Yang An , Yi Li

We compute the matching coefficients between QCD and non-relativistic QCD for external vector, axial-vector, scalar and pseudo-scalar currents up to three-loop order. We concentrate on the non-singlet contributions and present precise…

High Energy Physics - Phenomenology · Physics 2022-06-22 Manuel Egner , Matteo Fael , Fabian Lange , Kay Schönwald , Matthias Steinhauser

We present compact formulas for the box coefficients of the six-point NMHV one-loop amplitudes in N=8 supergravity. We explicitly demonstrate that the corresponding box integral functions, with these coefficients, have the complete IR…

High Energy Physics - Theory · Physics 2011-09-29 N. E. J. Bjerrum-Bohr , David C. Dunbar , Harald Ita

We show, for previously uncalculated examples containing a uniform mass in the loop, that it is possible to obtain complete massive one-loop gauge theory amplitudes solely from unitarity and known ultraviolet or infrared mass singularities.…

High Energy Physics - Phenomenology · Physics 2008-11-26 Z. Bern , A. G. Morgan

In four-dimensional theories with massless particles, the one-loop amplitudes can be expressed in terms of a basis of scalar integrals and rational terms. Since the scalar bubble integrals are the only UV divergent integrals, the sum of the…

High Energy Physics - Theory · Physics 2015-03-20 Yu-tin Huang , David A. McGady , Cheng Peng

We discuss a set of recently discovered quadratic relations between gauge theory amplitudes. Such relations give additional structural simplifications for amplitudes in QCD. Remarkably, their origin lie in an analogous set of relations that…

High Energy Physics - Phenomenology · Physics 2015-05-27 N. E. J. Bjerrum-Bohr , Poul H. Damgaard , Bo Feng , Thomas Sondergaard

In this letter, we study tree-level scattering amplitudes of scalar particles in the context of effective field theories. We use tools similar to the soft bootstrap to build an ansatz for cyclically ordered amplitudes and impose the…

High Energy Physics - Theory · Physics 2023-05-11 Taro V. Brown , Karol Kampf , Umut Oktem , Shruti Paranjape , Jaroslav Trnka

We discuss a simple procedure for computing one-loop quantum energies of any static field configuration that depends non-trivially on only a single spatial coordinate. We specifically focus on domain wall-type field configurations that…

High Energy Physics - Theory · Physics 2009-10-31 Andrei Parnachev , Laurence G. Yaffe

Factorization properties of one-loop gauge theory amplitudes have been used as checks on explicitly computed amplitudes and in the construction of ansatze for higher-point ones. In massless theories, such as QCD at high energies, infrared…

High Energy Physics - Phenomenology · Physics 2010-04-06 Z. Bern , G. Chalmers

We propose a new ``universal expansion" for one-loop amplitudes with arbitrary number of gluons in $D$ dimensions, which holds for general gauge theories with gluons/fermions/scalars in the loop, including pure and supersymmetric Yang-Mills…

High Energy Physics - Theory · Physics 2024-12-30 Qu Cao , Jin Dong , Song He , Fan Zhu

It is well known that forward limits of tree-level amplitudes (and those trivalent diagrams they consist of) produce one-loop amplitudes and trivalent diagrams with propagators linear in the loop momentum. They naturally arise from one-loop…

High Energy Physics - Theory · Physics 2022-09-07 Bo Feng , Song He , Yong Zhang , Yao-Qi Zhang

We calculate one-loop 2-point tachyon amplitudes in unoriented open-closed string field theory, and determine all the coupling constants of the interaction vertices in the theory. It is shown that the planar, nonplanar and nonorientable…

High Energy Physics - Theory · Physics 2009-10-31 Tsuguhiko Asakawa , Taichiro Kugo , Tomohiko Takahashi

Loop amplitudes are conveniently expressed in terms of master integrals whose coefficients carry the process dependent information. Similarly before integration, the loop integrands may be expressed as a linear combination of propagator…

High Energy Physics - Theory · Physics 2016-12-28 Harald Ita

We discuss new results in QCD obtained with string-based methods. These methods were originally derived from superstring theory and are significantly more efficient than conventional Feynman rules. This technology was a key ingredient in…

High Energy Physics - Theory · Physics 2007-05-23 Z. Bern , L. Dixon , D. A. Kosower

We compute the complete one-loop corrections to the simplest class of QCD gluon amplitudes, those with two color-adjacent opposite-helicity external particles. We present results for an arbitrary number of external legs. The computation…

High Energy Physics - Phenomenology · Physics 2009-11-11 Darren Forde , David A. Kosower

Various implementations of the Unitarity method have been developed to compute one-loop amplitudes in gauge theories. In this paper we present an implementation which uses canonical forms to generate the rational coefficients of the basis…

High Energy Physics - Phenomenology · Physics 2009-11-24 David C. Dunbar , Warren B. Perkins , Edmund Warrick