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We have calculated the n_f^2 and n_f^3 contributions to the flavour non-singlet structure functions F_2 and F_L in inclusive deep-inelastic scattering at the fourth order in the strong coupling alpha_s. The coefficient functions have been…

High Energy Physics - Phenomenology · Physics 2023-04-12 A. Basdew-Sharma , A. Pelloni , Franz Herzog , A. Vogt

We report results for the lowest even-$N$ moments of the flavor-nonsinglet structure functions $F_2$ and $F_L$ in QCD at the fourth order in the perturbative expansion in the strong coupling constant $\alpha_s$. Our results are presented in…

High Energy Physics - Phenomenology · Physics 2022-08-24 S. Moch , B. Ruijl , T. Ueda , J. A. M. Vermaseren , A. Vogt

We present here the first result on the three-loop gluon jet function in perturbative QCD. Using the three-loop coefficient functions [1,2] for deep-inelastic scattering via the exchange of a virtual photon that couples to quarks or a…

High Energy Physics - Phenomenology · Physics 2018-11-28 Pulak Banerjee , Prasanna K. Dhani , V. Ravindran

We have calculated the complete matrix of three-loop helicity-difference (`polarized') splitting functions Delta P_ik^(2), i,k = q,g, in massless perturbative QCD. In this note we briefly discuss some properties of the polarized splitting…

High Energy Physics - Phenomenology · Physics 2014-05-15 A. Vogt , S. Moch , J. A. M. Vermaseren

The scale evolution of parton distributions is determined by universal splitting functions. As a milestone towards the computation of these functions to four-loop order in QCD, we compute all contributions to the pure-singlet quark-quark…

High Energy Physics - Phenomenology · Physics 2024-12-02 Thomas Gehrmann , Andreas von Manteuffel , Vasily Sotnikov , Tong-Zhi Yang

We compute the next-to-next-to-leading order (NNLO) contributions to the three splitting functions governing the evolution of unpolarized non-singlet combinations of quark densities in perturbative QCD. Our results agree with all partial…

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

We present the analytic next-to-next-to-leading perturbative QCD corrections in the leading twist approximation for the moments N=2,4,6,8 of the flavour singlet deep inelastic structure functions F_2 and F_L. We calculate the three-loop…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. A. Larin , P. Nogueira , T. van Ritbergen , J. A. M. Vermaseren

We have computed the first 30 even-N moments for the double fermionic (nf^2) part of the quark-to-gluon splitting function P_{gq} at the fourth order of perturbative QCD via the renormalization of off-shell operator matrix elements. From…

High Energy Physics - Phenomenology · Physics 2023-10-06 G. Falcioni , F. Herzog , S. Moch , J. Vermaseren , A. Vogt

We discuss recent results on the three-loop (next-to-next-to-leading order, NNLO) time-like splitting functions of QCD and the two-loop (NNLO) coefficient functions in one-particle inclusive e+e- annihilation. These results form the basis…

High Energy Physics - Phenomenology · Physics 2009-11-11 A. Mitov , S. Moch , A. Vogt

We report on the status of a direct computation of the time-like splitting functions at next-to-next-to-leading order in QCD. Time-like splitting functions govern the collinear kinematics of inclusive hadron production and the evolution of…

High Energy Physics - Phenomenology · Physics 2015-10-28 Oleksandr Gituliar , Sven Moch

Both for quark flavor asymmetry and valence, we consider the anomalous dimension of the non-singlet twist-two quark operator of arbitrary Lorentz spin N at four loops in SU(nc) color gauge theory and present its term proportional to zeta(3)…

High Energy Physics - Phenomenology · Physics 2026-05-12 B. A. Kniehl , V. N. Velizhanin

The next-to-leading order (NLO) ($\mathcal{O}(\alpha_s^3)$) corrections for gluon fragmentation functions to a heavy quark-antiquark pair in ${^{3}\hspace{-0.6mm}P_{J}^{[1,8]}}$ states are calculated within the NRQCD factorization. We use…

High Energy Physics - Phenomenology · Physics 2020-11-11 Peng Zhang , Ce Meng , Yan-Qing Ma , Kuang-Ta Chao

We employ relations between spacelike and timelike deep-inelastic processes in perturbative QCD to calculate the next-to-next-to-leading order (NNLO) contributions to the timelike quark-quark and gluon-gluon splitting functions for the…

High Energy Physics - Phenomenology · Physics 2008-11-26 S. Moch , A. Vogt

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 the calculation of the three-loop QCD corrections to quark and gluon form factors. The relevant three-loop Feynman diagrams are evaluated and the resulting three-loop Feynman integrals are reduced to a small set of known master…

High Energy Physics - Phenomenology · Physics 2023-11-15 T. Gehrmann , E. W. N. Glover , T. Huber , N. Ikizlerli , C. Studerus

We present the next-to-next-to-leading order (NNLO) contributions to the main splitting functions for the evolution of longitudinally polarized parton densities of hadrons in perturbative QCD. The quark-quark and gluon-quark splitting…

High Energy Physics - Phenomenology · Physics 2015-06-22 S. Moch , J. A. M. Vermaseren , A. Vogt

The significance of NNLO (3-loop) QCD contributions to the flavor non-singlet sector of F_2^ep and F_2^ed has been studied as compared to uncertainties (different factorization schemes, higher twist and QED contributions) of standard NLO…

High Energy Physics - Phenomenology · Physics 2008-11-26 M. Glück , E. Reya , C. Schuck

The scale evolution of parton distributions is governed by splitting functions. We compute the four-loop splitting functions in perturbative QCD that control the evolution of quark non-singlet distributions. We confirm previous partial…

High Energy Physics - Phenomenology · Physics 2026-04-27 Thomas Gehrmann , Andreas von Manteuffel , Vasily Sotnikov , Tong-Zhi Yang

We compute the complete set of two-loop beam functions for the transverse momentum distribution of the leading jet produced in association with an arbitrary colour-singlet system. Our results constitute the last missing ingredient for the…

High Energy Physics - Phenomenology · Physics 2023-05-17 Samuel Abreu , Jonathan R. Gaunt , Pier Francesco Monni , Luca Rottoli , Robert Szafron

We study the evolution of the flavour non-singlet deep-inelastic structure functions F_{2,NS} and F_3 at the next-to-next-to-next-to-leading order (N^3LO) of massless perturbative QCD. The present information on the corresponding three-loop…

High Energy Physics - Phenomenology · Physics 2009-11-07 W. L. van Neerven , A. Vogt