Reassessment of the Collins Mechanism for Single-spin Asymmetries and the behavior of Delta d(x) at large x

Abstract

It is shown that the Collins mechanism explanation of the transverse single-spin asymmetries in p^{\uparrow} p -> πX leads to a transversely polarized d quark density Delta_T d(x) which violates the Soffer bound when one uses several standard forms for the longitudinally polarized d quark density Delta d(x) obtained from polarized deep inelastic scattering. Imposition of the Soffer bound with these Delta d(x) yields results in hopeless disagreement with the data. Remarkably, imposition of the Soffer bound, but using parametrizations of Delta d(x) that respect the PQCD condition Delta q(x) / q(x) -> 1 as x -> 1, leads to an excellent fit to most of the data. The implications for the polarized DIS neutron longitudinal asymmetry A_1^n at large x are dramatic.

arXiv comment13 pages, 11 figures, 1 table and 4 figures changed. Revised version to appear in Phys. Rev. D

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Cited by in corpus (18)

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• Cross Sections and Transverse Single-Spin Asymmetries in Forward Neutral-Pion Production from Proton Collisions at \sqrt{s} = 200 GeV
• Parton intrinsic motion in inclusive particle production: unpolarized cross sections, single spin asymmetries and the Sivers effect
• Lambda polarization from unpolarized quark fragmentation
• Accessing Sivers gluon distribution via transverse single spin asymmetries in p(transv. polarized) p --> D X processes at RHIC
• Parton intrinsic motion: suppression of the Collins mechanism for transverse single spin asymmetries in p(transv. polarised) p --> pion + X
• Sudakov suppression in azimuthal spin asymmetries
• Estimate of the Collins fragmentation function in a chiral invariant approach
• Transverse single spin asymmetries in Drell-Yan processes
• The Collins function: a simple model calculation
• Phenomenology of transverse spin: past, present and future
• Accessing Transversity in Double-Spin Asymmetries at the BNL-RHIC
• Probing the transverse spin of quarks in deep inelastic scattering
• Single Spin Asymmetry in Inclusive Hadron Production in pp Scattering from Collins Mechanism
• The Transversity Function and Double Spin Azimuthal Asymmetry in Semi-Inclusive Pion Leptoproduction
• Single spin asymmetries in QCD
• Origins of single transverse spin asymmetries
• Noncommutative Momentum for Arbitrary Spin Polarization