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Related papers: Order $\alpha_s(Q^2)$ QCD corrections to the polar…

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Power-suppressed corrections to parton evolution may affect the theoretical accuracy of current determinations of parton distributions. We study the role of multigluon-exchange terms in the extraction of the gluon distribution for the Large…

High Energy Physics - Phenomenology · Physics 2008-11-26 F. Hautmann

We develope the method of improvement of perturbative theory in QCD, applied to any polarization operator. The case of polarization operator \Pi(q^2), corresponding to the process e^+e^- -> hadrons is considered in details. Using the…

High Energy Physics - Phenomenology · Physics 2009-10-31 B. V. Geshkenbein , B. L. Ioffe

Experimental data from Belle Collaboration for the transverse polarization of $\Lambda$'s measured in $e^+ e^-$ annihilation processes are used to extract the polarizing fragmentation function (FF) within a TMD approach. We consider both…

High Energy Physics - Phenomenology · Physics 2021-08-03 Umberto D'Alesio , Francesco Murgia , Marco Zaccheddu

Analytic formulae are given for QCD corrections to the lepton spectra in decays of polarised up and down type heavy quarks. These formulae are much simpler than the published ones for the corrections to the spectra of charged leptons…

High Energy Physics - Phenomenology · Physics 2010-11-01 A. Czarnecki , M. Jeżabek

The fragmentation of an unpolarized quark into a transversely polarized spin-1/2 particle is studied in the framework of a simple model. Special attention is payed to the gluon exchange which is incorporated in the gauge link of the…

High Energy Physics - Phenomenology · Physics 2009-02-19 A. Metz

A QCD analysis of the world data on inclusive polarized deep inelastic scattering of leptons on nucleons is presented in leading and next-to-leading order. New parameterizations are derived for the quark and gluon distributions and the…

High Energy Physics - Phenomenology · Physics 2009-11-07 J. Blümlein , H. Böttcher

In the framework of the perturbative QCD and the diquark model of baryons we have obtained the fragmentation functions for heavy quark that split into polarized Lambda_b baryons. We predict the longitudinal polarization asymmetry for the…

High Energy Physics - Phenomenology · Physics 2016-09-06 V. A. Saleev

We investigate numerical solution of Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) Q^2 evolution equations for longitudinally polarized structure functions. Flavor nonsinglet and singlet equations with next-to-leading-order $\alpha_s$…

High Energy Physics - Phenomenology · Physics 2014-11-17 M. Hirai , S. Kumano , M. Miyama

We present MAPFF1.0_Lambda, the first global analysis at next-to-next-to-leading order in perturbative QCD of the collinear unpolarised fragmentation functions of Lambda hyperons. The fit is based on data from single-inclusive…

High Energy Physics - Phenomenology · Physics 2026-05-08 Valerio Bertone , Alessia Bongallino , Amedeo Chiefa , Miguel G. Echevarria , Gunar Schnell

We compute the relativistic corrections to the color-singlet contribution to gluon fragmentation into a J/psi at relative order v^4, making use of the nonrelativistic QCD (NRQCD) factorization approach. The corresponding full-QCD process…

High Energy Physics - Phenomenology · Physics 2013-01-17 Geoffrey T. Bodwin , U-Rae Kim , Jungil Lee

We compute relativistic corrections to the gluon fragmentation functions to ${}^3P_J^{[1,8]}$ Fock states of heavy quarkonium within non-relativistic QCD factorization framework. We find that, at $\mathcal{O}(v^2)$ sub-leading order, the…

High Energy Physics - Phenomenology · Physics 2026-02-20 Zhi-Guo He , Bernd A. Kniehl , Peng Zhang

Spin dependent structure function $g_1^{\gamma}(x,Q^2)$ of the polarised photon is analysed within the formalism based upon the unintegrated spin dependent parton distributions incorporating the LO Altarelli-Parisi evolution and the double…

High Energy Physics - Phenomenology · Physics 2014-11-17 J. Kwiecinski , B. Ziaja

In this contribution, we make use of the QCD perturbative fragmentation function formalism to describe the one-particle inclusive fragmentation of a heavy quark produced in $e^+e^-$ annihilation at $\mathcal{O}(\alpha_S^2)$. We perform the…

High Energy Physics - Phenomenology · Physics 2023-06-06 Leonardo Bonino , Matteo Cacciari , Giovanni Stagnitto

Compact analytic expressions have been obtained for the first order perturbative QCD corrections to the inclusive spectra of the leptons in the semileptonic decays of polarised heavy quarks. Charmed and beautiful $\Lambda$ baryons from…

High Energy Physics - Phenomenology · Physics 2007-05-23 Marek Jezabek

Perturbative solutions for unpolarized QED parton distribution and fragmentation functions are presented explicitly in the next-to-leading logarithmic approximation. The scheme of iterative solution of QED evolution equations is described…

High Energy Physics - Phenomenology · Physics 2023-09-06 A. B. Arbuzov , U. E. Voznaya

We compute the O(alpha_s) QCD corrections to the partonic process gg -> t-tbar-Z at the LHC. This partonic channel is the dominant component of the scattering process pp -> t-tbar-Z, which will be important for measuring the t-tbar-Z…

High Energy Physics - Phenomenology · Physics 2008-11-26 Achilleas Lazopoulos , Kirill Melnikov , Frank Petriello

We point out that the fragmentation of a strange quark into nucleons versus antinucleons is not necessarily identical $D_{p/s}(z,Q^2) \neq D_{\bar p/s}(z,Q^2)$, even though the perturbative contributions from gluon splitting and evolution…

High Energy Physics - Phenomenology · Physics 2009-09-11 S. J. Brodsky , B. -Q. Ma

We calculate the functions of parton fragmentation into $^3P_J$ quarkonium at order $\alpha_s ^2$, where the parton can be a heavy or light quark. The obtained functions explicitly satisfy the Altarelli-Parisi equation and they are…

High Energy Physics - Phenomenology · Physics 2010-11-01 J. P. Ma

We compute the relative-order-v^4 contribution to gluon fragmentation into quarkonium in the 3S1 color-singlet channel, using the nonrelativistic QCD (NRQCD) factorization approach. The QCD fragmentation process contains infrared…

High Energy Physics - Phenomenology · Physics 2023-07-25 Geoffrey T. Bodwin , U-Rae Kim , Jungil Lee

This work is devoted to the study of the $\{\beta\}$-expansion of the perturbative expressions for the $e^+e^-$ annihilation Adler function $D(Q^2)$ and for the related renormalization group functions, namely for the photon vacuum…

High Energy Physics - Phenomenology · Physics 2023-12-01 A. L. Kataev , V. S. Molokoedov