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We use on-shell recursion relations to determine the one-loop QCD scattering amplitudes with a massless external quark pair and an arbitrary number (n-2) of positive-helicity gluons. These amplitudes are the last of the unknown infrared-…

High Energy Physics - Phenomenology · Physics 2010-11-15 Zvi Bern , Lance J. Dixon , David A. Kosower

We report on further progress in understanding soft singularities of massless gauge theory scattering amplitudes. Recently, a set of equations was derived based on Sudakov factorization, constraining the soft anomalous dimension matrix of…

High Energy Physics - Phenomenology · Physics 2011-08-17 Lance J. Dixon , Einan Gardi , Lorenzo Magnea

Scattering amplitudes for the massless QCD process, $q\bar{q}\to q^\prime\bar{q}^\prime$, are calculated in the one-loop order in the Feynman-Diagram (FD) gauge, where gluons are quantized on the light cone with opposite direction of the…

High Energy Physics - Phenomenology · Physics 2024-07-17 Kaoru Hagiwara , Kentarou Mawatari , Youichi Yamada , Ya-Juan Zheng

We present a QCD study of fragmentation processes for light and heavy quarks in the semi-inclusive region of large x. Large logarithmic terms, due to soft-gluon radiation, are evaluated and resummed to all perturbative orders in the QCD…

High Energy Physics - Phenomenology · Physics 2010-05-28 M. Cacciari , S. Catani

Using a careful choice of infrared (IR) subtraction scheme, we demonstrate the cancellation of all terms with transcendental weights 0,1,2 from the finite part of the full-color two-loop four-gluon $\mathcal{N}=2$ supersymmetric QCD…

High Energy Physics - Theory · Physics 2020-02-19 Gregor Kälin , Gustav Mogull , Alexander Ochirov , Bram Verbeek

Splitting amplitudes are universal functions governing the collinear behavior of scattering amplitudes for massless particles. We compute the two-loop g -> gg splitting amplitudes in QCD, N=1, and N=4 super-Yang-Mills theories, which…

High Energy Physics - Phenomenology · Physics 2010-03-25 Zvi Bern , Lance J. Dixon , David A. Kosower

We compute the radiative corrections to the four-point amplitude $g+g \rightarrow A+A$ in massless Quantum Chromodynamics (QCD) up to order $a_s^4$ in perturbation theory. We used the effective field theory that describes the coupling of…

High Energy Physics - Phenomenology · Physics 2021-11-30 Arunima Bhattacharya , Maguni Mahakhud , Prakash Mathews , V. Ravindran

An outstanding problem in QCD and jet physics is the factorization and resummation of logarithms that arise due to phase space constraints, so-called non-global logarithms (NGLs). In this paper, we show that NGLs can be factorized and…

High Energy Physics - Phenomenology · Physics 2015-10-28 Andrew J. Larkoski , Ian Moult , Duff Neill

We study resummation of transverse-momentum-related large logarithms generated from soft-gluon radiations in soft-collinear effective field theory. The anomalous dimensions of the effective quark and gluon currents, an important ingredient…

High Energy Physics - Phenomenology · Physics 2010-04-05 Ahmad Idilbi , Xiangdong Ji , Feng Yuan

We consider the factorization and resummation of soft and Coulomb gluons for pair-production processes of heavy coloured particles at hadron colliders, and discuss: the construction of a colour basis that diagonalizes the leading soft…

High Energy Physics - Phenomenology · Physics 2010-01-27 M. Beneke , P. Falgari , C. Schwinn

In QCD hard scattering cross sections, the color content of the underlying hard scattering evolves with a factorization scale. This evolution is controlled by an anomalous dimension matrix, specific to each hard-scattering reaction.…

High Energy Physics - Phenomenology · Physics 2014-11-17 Nikolaos Kidonakis , Gianluca Oderda , George Sterman

We study the singularity structure of two-loop QED amplitudes for the production of multiple off-shell photons in massless electron-positron annihilation and develop counterterms that remove their infrared and ultraviolet divergences point…

High Energy Physics - Phenomenology · Physics 2021-04-26 Charalampos Anastasiou , Rayan Haindl , George Sterman , Zhou Yang , Mao Zeng

QCD amplitudes are one of the most important ingredients for the understanding of the early universe. In this work we present how the knowledge of the asymptotic states can be used to calculate the scattering amplitude of the underline QCD…

High Energy Physics - Theory · Physics 2022-12-02 Andriniaina Narindra Rasoanaivo

We compute the ${\cal O}(\alpha_s^3)$ virtual QCD corrections to the $\gamma^*\to q\bar q g$ matrix element arising from the interference of the two-loop with the tree-level amplitude and from the self-interference of the one-loop…

High Energy Physics - Phenomenology · Physics 2010-04-06 L. W. Garland , T. Gehrmann , E. W. N. Glover , A. Koukoutsakis , E. Remiddi

We obtain the quark and gluon rapidity anomalous dimension to fourth order in QCD. We calculate the N$^3$LO rapidity anomalous dimensions to higher order in the dimensional regulator and make use of the soft/rapidity anomalous dimension…

High Energy Physics - Phenomenology · Physics 2022-05-12 Claude Duhr , Bernhard Mistlberger , Gherardo Vita

Infra-red properties of the triangle anomaly and the ``anomaly pole'' are elaborated and applied to the study of high-energy scattering in QCD, when the gauge symmetry is partially broken to SU(2). It is shown that the chiral flavor anomaly…

High Energy Physics - Phenomenology · Physics 2009-11-07 Alan R. White

The renormalization of the scalar diquark operator and its anomalous dimension is calculated at two-loop order in QCD, enabling higher-order QCD studies of diquarks. As an application of our result, the two-loop diquark anomalous dimension…

High Energy Physics - Phenomenology · Physics 2011-11-30 R. T. Kleiv , T. G. Steele

The soft anomalous dimension governs the infrared divergences of scattering amplitudes in general kinematics to all orders in perturbation theory. By comparing the recent Regge-limit results for $2\to2$ scattering (through…

High Energy Physics - Phenomenology · Physics 2022-02-07 Niamh Maher , Giulio Falcioni , Einan Gardi , Calum Milloy , Leonardo Vernazza

We use the antenna subtraction method to isolate the infrared singularities present in QCD scattering amplitudes at next-to-next-to-leading order. In particular, infrared singularities due to double-real radiation and real-virtual radiation…

High Energy Physics - Phenomenology · Physics 2012-09-28 Joao Pires

Two-loop QCD correction to massive spin-2 Graviton decaying to $q ~ + ~ \bar{q}~ + ~g$ is presented considering a generic universal spin-2 coupling to the SM through the conserved energy-momentum tensor. Such a massive spin-2 particle can…

High Energy Physics - Phenomenology · Physics 2016-12-21 Taushif Ahmed , Goutam Das , Prakash Mathews , Narayan Rana , V. Ravindran