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We present the first complete next-to-next-to-next-to-leading-order calculation of the matching coefficients that link unpolarized flavor non-singlet parton distribution functions with lattice QCD computable correlation functions. By using…

High Energy Physics - Phenomenology · Physics 2024-10-11 Chen Cheng , Li-Hong Huang , Xiang Li , Zheng-Yang Li , Yan-Qing Ma

We calculate next-to-leading-order (NLO) correction to the pion electromagnetic form factor at leading twist in the $k_T$ factorization theorem. Partons off-shell by $k_T^2$ are considered in both quark diagrams and effective diagrams for…

High Energy Physics - Phenomenology · Physics 2015-03-17 Hsiang-nan Li , Yue-Long Shen , Yu-Ming Wang , Hao Zou

The parton distribution function of the pion in the valence region is extracted in a next-to-leading order analysis from Fermilab E-615 pionic Drell-Yan data. The effects of the parameterization of the pion's valence distributions are…

Nuclear Experiment · Physics 2009-11-11 K. Wijesooriya , P. E. Reimer , R. J. Holt

We calculate the next-to-leading order perturbative QCD corrections to the transverse momentum weighted single transverse spin asymmetry in Drell-Yan lepton pair production in hadronic collisions. We identify the splitting function relevant…

High Energy Physics - Phenomenology · Physics 2009-07-30 Werner Vogelsang , Feng Yuan

We suggest a new procedure for extrapolating the parton distributions from HERA energies to higher energies at THERA and LHC. The procedure suggested consists of two steps: first, we solve the non-linear evolution equation which includes…

High Energy Physics - Phenomenology · Physics 2014-11-17 M. Lublinsky , E. Gotsman , E. Levin , U. Maor

The twist three contributions to the $Q^2$-evolution of the spin-dependent structure function $g_2(x_{Bj},Q^2)$ are considered in the non-local operator product approach. Defining appropriate twist three distribution function we derive…

High Energy Physics - Phenomenology · Physics 2007-05-23 B. Geyer , D. Müller , D. Robaschik

We compute the next-to-next-to-leading order (NNLO) QCD corrections to the thrust distribution in electron-positron annihilation. The corrections turn out to be sizable, enhancing the previously known next-to-leading order prediction by…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. Gehrmann-De Ridder , T. Gehrmann , E. W. N. Glover , G. Heinrich

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 study the transverse momentum dependent (TMD) parton distributions at small-x in a consistent framework that takes into account the TMD evolution and small-x evolution simultaneously. The small-x evolution effects are included by…

High Energy Physics - Phenomenology · Physics 2017-06-28 Bo-Wen Xiao , Feng Yuan , Jian Zhou

We present the method, based on the use of the broken conformal Ward identities, for the calculation of the anomalous dimensions of conformal operators beyond the leading order of perturbation theory. By means of this technique we find the…

High Energy Physics - Phenomenology · Physics 2014-11-17 A. V. Belitsky , D. Mueller

We complete the perturbative next-to-leading order corrections to the hard scattering amplitudes of deeply virtual meson leptoproduction processes at leading twist-two level by presenting the results for the production of flavor singlet…

High Energy Physics - Phenomenology · Physics 2017-06-14 G. Duplančić , D. Müller , K. Passek-Kumerički

QCD in non-integer d=4-2 epsilon space-time dimensions possesses a nontrivial critical point and enjoys exact scale and conformal invariance. This symmetry imposes nontrivial restrictions on the form of the renormalization group equations…

High Energy Physics - Phenomenology · Physics 2015-06-19 V. M. Braun , A. N. Manashov

We compute the next-to-next-to-leading order (NNLO) QCD corrections to event shape distributions and their mean values in deep inelastic lepton-nucleon scattering. The magnitude and shape of the corrections varies considerably between…

High Energy Physics - Phenomenology · Physics 2019-09-09 T. Gehrmann , A. Huss , J. Mo , J. Niehues

We systematically study the large-$q_T$ (or small-$b$) matching of transverse momentum dependent (TMD) distributions to the twist-2 integrated parton distributions. Performing operator product expansion for a generic TMD operator at the…

High Energy Physics - Phenomenology · Physics 2017-08-15 Daniel Gutierrez-Reyes , Ignazio Scimemi , Alexey A. Vladimirov

We analyze a toy model which has a structure similar to that of the recently found QCD evolution equations, but without transverse dimensions. We develop two different but equivalent methods in order to compute the leading-order and…

High Energy Physics - Phenomenology · Physics 2008-11-26 Arif I. Shoshi , Bo-Wen Xiao

We present the first calculations of next-to-next-to-next-to-next-to-leading order (N^4LO) contributions to anomalous dimensions of spin-N twist-2 operators in perturbative QCD. Specifically, we have obtained the respective non-singlet…

High Energy Physics - Phenomenology · Physics 2019-02-06 F. Herzog , S. Moch , B. Ruijl , T. Ueda , J. A. M. Vermaseren , A. Vogt

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

I consider variations in the definitions, at next-to-leading order (NLO) and at next-to-next-to leading order (NNLO), of a General-Mass Variable Flavour Number Scheme (GM-VFNS) for heavy flavour structure functions. I also define a new…

High Energy Physics - Phenomenology · Physics 2012-11-12 R. S. Thorne

Three-body decay functions in space-like parton branches are implemented to evaluate transverse-momentum-dependent (TMD) parton distribution functions in the next-to-leading logarithmic (NLL) order of quantum chromodynamics (QCD).…

High Energy Physics - Phenomenology · Physics 2015-04-08 Hidekazu Tanaka

We study the Q^2 evolution of parton distributions at small x values, obtained in the case of flat initial conditions. The contributions of twist-two and (renormalon-type) higher-twist operators of the Wilson operator product expansion are…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. V. Kotikov , G. Parente