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Related papers: Q^2-evolution of spin-dependent parton densities

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Semi-inclusive hadron production in longitudinally polarized deep-inelastic lepton-nucleon scattering is a powerful tool for resolving the quark flavor decomposition of the proton's spin structure. We present the full…

High Energy Physics - Phenomenology · Physics 2025-10-02 Leonardo Bonino , Thomas Gehrmann , Markus Löchner , Kay Schönwald , Giovanni Stagnitto

We present the full next-to-leading order (NLO) corrected inclusive cross section $d^3\Delta \sigma/dQ^2/dy/dp_T$ for massive lepton pair production in longitudinally polarized proton-proton collisions $p + p\to l^+l^- + 'X'$. Here $'X'$…

High Energy Physics - Phenomenology · Physics 2010-04-05 V. Ravindran , J. Smith , W. L. van Neerven

We derive a new twist-3 partonic sum rule for the transverse spin of the proton, which involves the well-know quark spin structure function $g_T(x)=g_1(x)+g_2(x)$, the less-studied but known transverse gluon polarization density $\Delta…

High Energy Physics - Phenomenology · Physics 2021-06-30 Yuxun Guo , Xiangdong Ji , Kyle Shiells

Nuclear parton distributions $f_A(x,Q^2)$ are studied within a framework of the DGLAP evolution. Measurements of $F_2^A/F_2^D$ in deep inelastic $lA$ collisions, and Drell--Yan dilepton cross sections measured in $pA$ collisions are used as…

High Energy Physics - Phenomenology · Physics 2015-06-25 K. J. Eskola , V. J. Kolhinen , P. V. Ruuskanen , C. A. Salgado

The spin structure of the nucleon is studied in a light-cone description of the nucleon where the Fock expansion is truncated to consider only valence quarks. Transverse momentum dependent parton distributions and transverse-spin densities,…

High Energy Physics - Phenomenology · Physics 2008-11-26 B. Pasquini

Starting with the interpretation of parton evolution with rapidity as a branching-diffusion process, we describe the different kinds of fluctuations of the density of partons which affect the properties of QCD scattering amplitudes at…

High Energy Physics - Phenomenology · Physics 2014-09-16 A. H. Mueller , S. Munier

We shown the general approach for Q2 evolution of parton densities and fragmentation functions at low x based on the diagonalization. The diagonalization leads to the two components in the Q2 evolution, each of which contains a…

High Energy Physics - Phenomenology · Physics 2015-02-26 Anatoly Kotikov

We have computed the complete next-to-next-to-leading order (NNLO) contributions to the splitting functions governing the evolution of unpolarized parton densities in perturbative QCD. Our results agree with all partial results available in…

High Energy Physics - Phenomenology · Physics 2009-11-10 S. Moch , J. A. M. Vermaseren , A. Vogt

The higher twist corrections $h^N(x)/Q^2$ to the spin dependent proton and neutron structure functions $g_1^N(x, Q^2)$ are extracted in a model independent way from experimental data on $g_1^N$ and found to be non-negligible. It is shown…

High Energy Physics - Phenomenology · Physics 2009-11-07 E. Leader , A. V. Sidorov , D. B. Stamenov

$Q^2$ evolution of the structure functions $F_2$ in tin and carbon nuclei is investigated in order to understand recent NMC measurements. $F_2$ is evolved by using leading-order DGLAP, next-to-leading-order DGLAP, and parton-recombination…

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

In this work we have solved the nonlinear GLR-MQ evolution equation upto next-to-leading order (NLO) by considering NLO terms of the gluon-gluon splitting functions and running coupling constant $\alpha_s(Q^2)$. Here, we have incorporated a…

High Energy Physics - Phenomenology · Physics 2018-01-22 M. Lalung , P. Phukan , J. K. Sarma

We study the next-to-next-to-leading order (NNLO) evolution of flavour singlet parton densities and structure functions in massless perturbative QCD. Present information on the corresponding three-loop splitting functions is used to derive…

High Energy Physics - Phenomenology · Physics 2009-10-31 W. L. van Neerven , A. Vogt

We report on a next-to-leading order QCD calculation of the cross section and the spin asymmetry for isolated large-p_T prompt photon production in collisions of transversely polarized protons. Corresponding measurements may be used at RHIC…

High Energy Physics - Phenomenology · Physics 2009-11-10 A. Mukherjee , M. Stratmann , W. Vogelsang

We present preliminary results on the leading-twist transverse-momentum-dependent (TMD) gluon linearity function, which is directly connected to nucleon transverse-spin asymmetries originating from the density of linearly-polarized gluons.…

High Energy Physics - Phenomenology · Physics 2022-03-11 Alessandro Bacchetta , Francesco Giovanni Celiberto , Marco Radici

We calculate the chiral odd quark distributions and the corresponding structure functions $h_T(x,Q^2)$ and $h_L(x,Q^2)$ within the Nambu-Jona-Lasinio chiral soliton model for the nucleon. The $Q^2$ evolution of the twist-2 contributions is…

High Energy Physics - Phenomenology · Physics 2016-09-06 L. Gamberg , H. Reinhardt , H. Weigel

We report global analysis results for polarized parton distribution functions in the nucleon. The optimum distributions are determined by using spin asymmetry data on polarized lepton scattering on proton, neutron, and deuteron. Their…

High Energy Physics - Phenomenology · Physics 2009-11-11 M. Hirai , S. Kumano , N. Saito

A recent global QCD analysis of jet production and other polarized scattering data has found the presence of negative solutions for the gluon helicity distribution in the proton, $\Delta g$, along with the traditional $\Delta g > 0$…

High Energy Physics - Phenomenology · Physics 2026-05-04 R. M. Whitehill , Yiyu Zhou , N. Sato , W. Melnitchouk

We report progresses on leading-twist transverse-momentum-dependent (TMD) gluon distributions, calculated in a spectator-model framework for the parent nucleon. We encode in our formalism a fit-based parameterization for the spectator-mass…

High Energy Physics - Phenomenology · Physics 2022-03-11 Alessandro Bacchetta , Francesco Giovanni Celiberto , Marco Radici

We evaluate both chirally even and odd generalized parton distributions(GPDs) in the leading twist in a recently proposed quark-diquark model for the proton where the light front wavefunctions are constructed from the soft-wall AdS/QCD…

High Energy Physics - Phenomenology · Physics 2017-08-02 Tanmay Maji , Chandan Mondal , Dipankar Chakrabarti

We discuss the general properties of generalized parton distributions with helicity flip (transversity) for spin-1 hadrons in the leading twist case. Using a basic light cone convolution model, we show the deuteron helicity amplitudes…

High Energy Physics - Phenomenology · Physics 2020-01-08 W. Cosyn , B. Pire