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Related papers: Nucleon longitudinal spin structure at COMPASS

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Transverse spin and transverse momentum distribution functions of the constituents of the nucleon are a crucial input for a complete description of the nucleon. COMPASS measured such for longitudinally and transversely polarized deuterons…

High Energy Physics - Experiment · Physics 2019-08-13 H. Wollny

We compare constraints on the gluon polarization in the nucleon obtained in next to leading order global QCD fits to polarized deep inelastic scattering data with those coming from observables more directly linked to the gluon polarization,…

High Energy Physics - Phenomenology · Physics 2008-11-26 G. A. Navarro , R. Sassot

A theoretical approach to the investigation of spin-dependent structure functions in deep inelastic scattering of polarized leptons off polarized nuclei, based on the effective meson-nucleon theory and operator product expansion method, is…

Nuclear Theory · Physics 2009-09-25 L. P. Kaptari , A. Yu. Umnikov , C. Ciofi degli Atti , S. Scopetta , K. Yu. Kazakov

COMPASS is a fixed-target high energy physics experiment at the SPS at CERN \cite{Abbon:2007pq}. One of the important objectives of the experiment is the exploration of the transverse spin structure of the nucleon via spin dependent…

High Energy Physics - Experiment · Physics 2015-06-12 Bakur Parsamyan

I review recent theoretical results on polarized deep inelastic lepton nucleon scattering. Some specific issues, like $Q^2$ evolution of structure functions, the small $x$ behaviour, and the determination of polarized parton densities, are…

High Energy Physics - Phenomenology · Physics 2007-05-23 Giovanni Ridolfi

These lectures introduce the non-specialist to the evaluation of spin structure functions from asymmetries measured in polarized deep-inelastic scattering experiments. The various steps leading from apparatus dependent counting rate…

High Energy Physics - Phenomenology · Physics 2007-05-23 R. Windmolders

By assuming that there is no significant intrinsic polarization of the gluon, we have computed the polarized quark contributions to the proton's spin under SU(3) flavor symmetry breaking for the polarized sea and have performed a global…

High Energy Physics - Phenomenology · Physics 2009-10-28 Chung-Yi Wu

The spin structure of the nucleon is analyzed in the framework of a Lorentz-invariant formulation of baryon chiral perturbation theory. The structure functions of doubly virtual Compton scattering are calculated to one-loop accuracy (fourth…

High Energy Physics - Phenomenology · Physics 2009-11-07 Véronique Bernard , Thomas R. Hemmert , Ulf-G. Meißner

One of the key objectives of the COMPASS experiment at CERN is the determination of the gluon contribution to the nucleon spin. The gluon polarization is measured via photon-gluon fusion in deep-inelastic scattering of 160 GeV/c polarized…

High Energy Physics - Experiment · Physics 2017-08-23 C. Schill

The deuteron is the lightest spin-1 nucleus, consisting of a weakly bound system of two spin-1/2 nucleons. One intriguing characteristic of the deuteron is the tensor polarized structure, which cannot be naively constructed combining the…

Nuclear Experiment · Physics 2025-06-06 Jiwan Poudel , Alessandro Bacchetta , Jian-Ping Chen , Nathaly Santiesteban

Physics perspectives are shown for future experiments in electron or positron scattering on nucleons, towards a deep and comprehensive understanding of the angular momentum structure of the nucleon in the context of Quantum Chromodynamics.…

High Energy Physics - Phenomenology · Physics 2007-05-23 Wolf-Dieter Nowak

One of the main goals of the COMPASS experiment at CERN is the determination of the gluon contribution to the nucleon spin. To achieve this goal COMPASS uses a naturally polarised muon beam with an energy of 160 GeV and a fixed polarised…

High Energy Physics - Experiment · Physics 2012-09-03 Celso Franco

In order to obtain polarised parton densities we have made next to leading order QCD fit using experimental data on deep inelastic structure functions on nucleons. This fit is compared with the updated fit to coresponding spin asymmetries.…

High Energy Physics - Phenomenology · Physics 2009-11-07 Jan Bartelski , Stanislaw Tatur

One of the goals of COMPASS experiment is the determination of the gluon polarisation, \Delta G/G, for a deep understanding of the spin structure of the nucleon. The gluon polarisation can be measured via the Photon-Gluon-Fusion (PGF)…

High Energy Physics - Experiment · Physics 2019-08-13 Luís Silva

One of the important questions in high energy physics is the relation of quark and gluon spin to that of the nucleons which they comprise. Polarization experiments provide a mechanism to probe the spin properties of elementary particles and…

High Energy Physics - Phenomenology · Physics 2014-11-17 Gordon P. Ramsey

The COMPASS experiment will determine the gluon polarization in the nucleon $\Delta G/G$ from the double helicity asymmetry measured in the scattering of a 160 GeV muon beam on a longitudinally polarized deuteron target, by selecting the…

High Energy Physics - Experiment · Physics 2019-08-14 C. Bernet

Dyson-Schwinger equation treatments of the strong interaction show that the presence and importance of nonpointlike diquark correlations within the nucleon are a natural consequence of dynamical chiral symmetry breaking. Using this…

Nuclear Theory · Physics 2015-06-16 Craig D. Roberts , Roy J. Holt , Sebastian M. Schmidt

The inclusive double-spin asymmetry, A_1^p, has been measured at COMPASS in deepinelastic polarised muon scattering off a large polarised NH3 target. The data, collected in the year 2007, cover the range Q2 > 1 (GeV/c)^2, 0.004 < x < 0.7…

High Energy Physics - Experiment · Physics 2014-11-20 The COMPASS Collaboration , M. G. Alekseev

A qualitative QCD analysis and a quantitative model calculation are given to show that the constituent quark model remains a good approximation even with the nucleon spin structure revealed in polarized deep inelastic scattering taking into…

High Energy Physics - Phenomenology · Physics 2008-11-26 Di Qing , Xiang-Song Chen , Fan Wang

The COMPASS experiment is a fixed-target high-energy physics experiment that has been collecting data for 20 years (2002 to 2022) at the M2 beamline (SPS, North Area) at CERN. One of the goals of the experiment's broad physics program was…

High Energy Physics - Experiment · Physics 2024-10-11 Siranush Asatryan