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We update our approximate parametrizations of the three-loop splitting functions for the evolution of unpolarized parton densities in perturbative QCD. The new information taken into account is given by the additional Mellin moments…

High Energy Physics - Phenomenology · Physics 2008-11-26 W. L. van Neerven , A. Vogt

We describe a procedure to determine moments of parton distribution functions of any order in lattice quantum chromodynamics (QCD). The procedure is based on the gradient flow for fermion and gauge fields. The flowed matrix elements of…

High Energy Physics - Lattice · Physics 2024-10-03 Andrea Shindler

We present the third-order contributions to the quark-gluon and gluon-quark timelike splitting functions for the evolution of fragmentation functions in perturbative QCD. These quantities have been derived by studying physical evolution…

High Energy Physics - Phenomenology · Physics 2015-05-28 A. A. Almasy , A. Vogt , S. Moch

Double parton distributions (DPDs) receive a short-distance contribution from a single parton splitting to yield the two observed partons. We investigate this mechanism at next-to-leading order (NLO) in perturbation theory. Technically, we…

High Energy Physics - Phenomenology · Physics 2019-08-07 Markus Diehl , Jonathan R. Gaunt , Peter Ploessl , Andreas Schafer

We present here the latest results from the QCDSF collaboration for (moments of) structure functions and generalized form factors in full QCD with Nf=2 O(a)-improved Wilson fermions based on simulations closer to the chiral and continuum…

High Energy Physics - Lattice · Physics 2008-11-26 M. Göckeler , P. Hägler , R. Horsley , D. Pleiter , P. E. L. Rakow , A. Schäfer , G. Schierholz , J. M. Zanotti

We study the splitting functions for the evolution of fragmentation distributions and the coefficient functions for single-hadron production in semi-inclusive electron-positron annihilation in massless perturbative QCD for small values of…

High Energy Physics - Phenomenology · Physics 2015-06-05 C. -H. Kom , A. Vogt , K. Yeats

We present a systematic decomposition of QCD splitting functions into scalar dipole radiators and pure splitting remainders up to second order in the strong coupling. The individual components contain terms that are formally sub-leading in…

High Energy Physics - Phenomenology · Physics 2026-02-06 John M. Campbell , Stefan Höche , Max Knobbe , Christian T. Preuss , Daniel Reichelt

We report on recent progress on the splitting functions for the evolution of parton distributions and related quantities, the (lightlike) cusp anomalous dimensions, in perturbative QCD. New results are presented for the four-loop…

High Energy Physics - Phenomenology · Physics 2018-08-29 A. Vogt , F. Herzog , S. Moch , B. Ruijl , T. Ueda , J. A. M. Vermaseren

We discuss the combined effect of QED and QCD corrections to the evolution of parton distributions. We extend the available knowledge of the Altarelli-Parisi splitting functions to one order higher in QED, and provide explicit expressions…

High Energy Physics - Phenomenology · Physics 2017-11-15 Daniel de Florian , German F. R. Sborlini , German Rodrigo

We have calculated the splitting functions governing the evolution of the unpolarized parton distributions of the photon at the next-to-next-to-leading order (NNLO) of massless perturbative QCD. The results, presented here mainly in terms…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. Vogt , S. Moch , J. Vermaseren

We present analytical results at four-loop level for the $\beta$-function of the coupling of a generic gauge group and any number of different quark representations. From this we can directly derive the gluino contribution to the strong…

High Energy Physics - Phenomenology · Physics 2017-07-25 M. F. Zoller

We present a first analysis of parton-to-pion fragmentation functions at next-to-next-to-leading order accuracy in QCD based on single-inclusive pion production in electron-positron annihilation. Special emphasis is put on the technical…

High Energy Physics - Phenomenology · Physics 2016-04-11 Daniele P. Anderle , Felix Ringer , Marco Stratmann

We have computed the next-to-next-to-leading-order (NNLO) contributions to the evolution of unpolarized parton distributions in perturbative QCD. In this talk, we briefly recall why this huge computation was necessary and outline how it was…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. Vogt , S. Moch , J. Vermaseren

We give a detailed account of the phenomenology of all-order resummations of logarithmically enhanced contributions at small momentum fraction of the observed hadron in semi-inclusive electron-positron annihilation and the time-like scale…

High Energy Physics - Phenomenology · Physics 2017-03-15 Daniele P. Anderle , Tom Kaufmann , Felix Ringer , Marco Stratmann

In this review, we discuss the results on the parton-to-pion fragmentation functions obtained in a combined NLO fit to data of single-inclusive hadron production in electron-positron annihilation, proton-proton collisions, and…

High Energy Physics - Phenomenology · Physics 2016-11-23 R. J. Hernández-Pinto , M. Epele , D. de Florian , R. Sassot , M. Stratmann

We present results on the fourth-order splitting functions and coefficient functions obtained using Forcer, a four-loop generalization of the Mincer program for the parametric reduction of self-energy integrals. We have computed the…

High Energy Physics - Phenomenology · Physics 2016-05-27 B. Ruijl , T. Ueda , J. A. M. Vermaseren , J. Davies , A. Vogt

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 summarize recent higher-order QCD results based, directly or indirectly, on the Mellin-space computation of the next-to-next-to-leading-order splitting functions governing the evolution of hadronic parton distributions. Specifically, we…

High Energy Physics - Phenomenology · Physics 2011-04-11 A. Vogt , S. Moch , J. Vermaseren

We report on the first calculation of the structure function g_1 in polarised deep-inelastic scattering to the third order in massless perturbative QCD. The calculation follows the dispersive approach already used for the corresponding…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. Vogt , S. Moch , M. Rogal , J. A. M. Vermaseren

We have extended our previous computations, performed analytically for a general gauge group, of the even-$N$ moments $\gamma_{\rm ik}^{\,(3)}(N)$ of the four-loop flavour-singlet splitting functions $P_{\rm ik}^{\,(3)}(x)$ to $N = 22$. The…

High Energy Physics - Phenomenology · Physics 2025-12-12 G. Falcioni , F. Herzog , S. Moch , A. Pelloni , A. Vogt