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We review recent progress on the calculation of scattering amplitudes in the high-energy limit. We start by illustrating the shockwave formalism, which allows one to calculate amplitudes as iterated solutions of rapidity evolution…

High Energy Physics - Phenomenology · Physics 2021-11-10 Leonardo Vernazza , Giulio Falcioni , Einan Gardi , Niamh Maher , Calum Milloy

The possibility of treating colour in one-loop amplitude calculations alike the other quantum numbers is briefly discussed for semi-numerical algorithms based on generalized unitarity and parametric integration techniques. Numerical results…

High Energy Physics - Phenomenology · Physics 2015-03-17 Jan Winter

We compute the one-loop corrections to \tth up to order $\mathcal{O}(\epsilon^2)$ in the dimensional regularization parameter. We apply the projector method to compute polarized amplitudes, which generalize massless helicity amplitudes to…

High Energy Physics - Phenomenology · Physics 2023-12-18 Federico Buccioni , Philipp Alexander Kreer , Xiao Liu , Lorenzo Tancredi

We obtain a simple relation between massless and massive scattering amplitudes in gauge theories in the limit where all kinematic invariants are large compared to particle masses. We use this relation to derive the two-loop QED corrections…

High Energy Physics - Phenomenology · Physics 2009-11-13 Thomas Becher , Kirill Melnikov

In this note, we propose a factorization formula for gauge-theory scattering amplitudes up to two loops in the high-energy boosted limit. Our formula extends existing results in the literature by incorporating the contributions from massive…

High Energy Physics - Phenomenology · Physics 2023-12-20 Guoxing Wang , Tianya Xia , Li Lin Yang , Xiaoping Ye

We compute the leading colour contributions to five-gluon scattering at two loops in massless QCD. The integrands of all independent helicity amplitudes are evaluated using d-dimensional generalised unitarity cuts and finite field…

High Energy Physics - Phenomenology · Physics 2018-03-07 Simon Badger , Christian Brønnum-Hansen , Heribertus Bayu Hartanto , Tiziano Peraro

I review recent progress in perturbative QCD on two fronts: extending next-to-next-to-leading order QCD corrections to a broader range of collider processes, and applying twistor-space methods (and related spinoffs) to computations of…

High Energy Physics - Phenomenology · Physics 2010-11-15 Lance J. Dixon

We calculate the unpolarized and polarized two--loop massless off--shell operator matrix elements in QCD to $O(\varepsilon)$ in the dimensional parameter in an automated way. Here we use the method of arbitrary high Mellin moments and…

High Energy Physics - Phenomenology · Physics 2022-05-04 J. Blümlein , P. Marquard , C. Schneider , K. Schönwald

We present analytic results for one of two types of planar QED two-loop integrals for $\mu e$ scattering including finite lepton masses. No approximations are made, such that the results are valid not only in the limit of a small electron…

High Energy Physics - Phenomenology · Physics 2021-05-18 Matthias Heller

Theoretical predictions for Bhabha scattering at the two-loop level require the inclusion of hadronic vacuum polarization in the photon propagator. We present predictions for the contributions from reducible amplitudes which are…

High Energy Physics - Phenomenology · Physics 2008-11-26 Johann H. Kühn , Sandro Uccirati

We present one-loop results for the forward twist-two matrix elements relevant to the unpolarised, helicity and transversity baryon structure functions, in partially-quenched (N_f=2 and N_f=2+1) heavy baryon chiral perturbation theory. The…

High Energy Physics - Lattice · Physics 2008-11-26 William Detmold , C. -J. David Lin

We compute squared matrix elements at next-to-next-to-leading order in perturbative quantum chromodynamics for the production of two or three (on- or off-shell) photons mediated via (light or heavy) quark loops. Our method handles all cases…

High Energy Physics - Phenomenology · Physics 2025-10-22 Dario Kermanschah , Matilde Vicini

The soft current describes the factorization behavior of quantum chromodynamics (QCD) scattering amplitudes in the limit of vanishing energy of one of the external partons. It is process-independent and can be expanded in a perturbative…

High Energy Physics - Phenomenology · Physics 2015-06-17 Claude Duhr , Thomas Gehrmann

The two-loop QCD radiative corrections to the $B_c$ meson leptonic decay rate are calculated in the framework of NRQCD factorization formalism. Two types of master integrals appearing in the calculation are obtained analytically for the…

High Energy Physics - Phenomenology · Physics 2015-07-29 Long-Bin Chen , Cong-Feng Qiao

Double parton distributions at small distances between the two partons are dominated by a mechanism in which the two observed partons originate from the splitting of a single parton. This contribution can be computed in terms of…

High Energy Physics - Phenomenology · Physics 2026-02-23 Markus Diehl , Peter Ploessl

In this article we discuss the calculation of single top-quark production in the t channel at two-loop order in QCD. In particular we present the decomposition of the amplitude according to its spin and colour structure and present complete…

High Energy Physics - Phenomenology · Physics 2014-12-22 M. Assadsolimani , P. Kant , B. Tausk , P. Uwer

I discuss the status of the computation of the two-loop QCD corrections to top-quark pair production associated with a jet at hadron colliders. This amplitude is a missing ingredient for next-to-next-to-leading order (NNLO) QCD predictions.…

High Energy Physics - Phenomenology · Physics 2024-11-19 Colomba Brancaccio

I discuss recent progress in the calculation of two-loop QCD corrections in the eikonal approximation. I present specific results for the UV structure of the corrections.

High Energy Physics - Phenomenology · Physics 2007-05-23 Nikolaos Kidonakis

We review progress in calculating one-loop scattering amplitudes required for next-to-leading-order corrections to QCD processes. The underlying technical developments include the spinor helicity formalism, color decompositions,…

High Energy Physics - Phenomenology · Physics 2010-11-15 Z. Bern , L. Dixon , D. A. Kosower

We report on recent progress on five-loop calculations in perturbative QCD. We discuss the computation of the perturbative quark condensate, decoupling in QCD, and the precision determination of charm and bottom quark masses. For the…

High Energy Physics - Phenomenology · Physics 2024-07-24 Andreas Maier , Peter Marquard , York Schröder