PHENOMENOLOGICAL APPROACH TO UNPOLARIZED AND POLARIZED PARTON DISTRIBUTIONS AND EXPERIMENTAL TESTS

Abstract

We recall our recent description of quark parton densities of the proton at $Q^2=4Ge{V}^2$ in terms of Fermi-Dirac distributions parametrized with very few free parameters. We have also proposed some simple assumptions to relate unpolarized and polarized quark parton densities which lead to a fair description of the spin-dependent structure functions $x{g}_1^p(x,Q^2)$ and $x{g}_1^n(x,Q^2)$ at low $Q^2$. We will show the predictions we obtain after a straightforward DGLAP $Q^2$ evolution and comparison in a much broader $x$ and $Q^2$ range, with several recent and accurate deep-inelastic scattering data. In particular, we will see that we get an excellent agreement with the sharp rise of $F_2^{ep}(x,Q^2)$ for small $x$, recently observed at HERA. Finally, we give several predictions for lepton pair and gauge boson production in $pp$ and $pn$ collisions at high energies which will be tested in the future at RHIC.

23 pages, in Latex, 31 ps figures (in a separated file tar-gzip-uuencoded form)

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• Measurement of the Spin-Dependent Structure Function $g_1(x)$ of the Proton
• Parton Distributions of the Proton
• Positivity Constraints for Spin-Dependent Parton Distributions
• CTEQ Parton Distributions and Flavor Dependence of Sea Quarks
• A Measurement of the Proton Structure Function $F_2(x,Q^2)$
• Novel Quark Fragmentation Functions and the Nucleon's Transversity Distribution
• The next-to-leading QCD approximation to the Ellis-Jaffe sum rule
• Spin-dependent Parton Distributions from Polarized Structure Function Data
• Parton Distributions from W+- and Z Production in Polarized pp and pn Collisions at RHIC
• The Charge Asymmetry in W-Boson Decays Produced in p-pbar Collisions at sqrt(s) = 1.8 TeV
• Calculation of Chirality Violating Proton Structure Function h${}_1$(x) in QCD
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Cited by in corpus (42)

• Extraction of Spin-Dependent Parton Densities and Their Uncertainties
• QCD Analysis of Polarized Deep Inelastic Data and Parton Distributions
• The Spin Structure of the Nucleon
• The Quark Spin Distributions of the Nucleon
• The statistical parton distributions: status and prospects
• Tensor Charges of the Nucleon in the SU(3) Chiral Quark Soliton Model
• Threshold Resummation for W-Boson Production at RHIC
• Drell-Yan processes, transversity and light-cone wavefunctions
• Statistical effect in the parton distribution functions of the nucleon
• Double-Spin Transverse Asymmetries in Drell-Yan Processes
• Single-spin asymmetries with weak bosons at RHIC
• QCD Selection Rules in Polarized Hadron Collisions
• Dilepton production near partonic threshold in transversely polarized proton-antiproton collisions
• Accessing Transversity in Double-Spin Asymmetries at the BNL-RHIC
• Statistical approach for unpolarized fragmentation functions for the octet baryons
• QCD expectations for the spin structure function $g_1$ in the low $x$ region
• Nuclear EMC Effect in a Statistical Model
• Probing quark compositeness at hadronic colliders : the case of polarized beams
• Testing various polarized parton distributions at RHIC
• Next-to-leading order QCD corrections to A_TT for prompt photon production
• Spin asymmetries in one-jet production at RHIC with polarized proton beams : the effects of a hadrophilic Z'
• Soft parton radiation in polarized vector boson production: theoretical issues
• The Spin Structure of the Proton and Polarized Collider Physics
• Spin Physics with the PHENIX Detector System
• Further experimental tests for simple relations between unpolarized and polarized quark parton distributions
• Parity-violating asymmetry of $W$ bosons produced in $p$-$p$ collisions
• Discovery limits for a new contact interaction at future hadronic colliders with polarized beams
• Gluon polarization in transversely polarized nucleons and jet spin asymmetries at RHIC
• A positivity bound for the longitudinal gluon distribution in a nucleon
• Spin Structure of the Proton and Large p_T Processes in Polarized pp Collisions
• Theoretical issues of small $x$ physics
• Critical Phenomena in DIS
• HERA prospects on Compositeness and New Vector Bosons
• Effect of sea quarks on the single-spin asymmetries $A_L^{W^{\pm }}$ in polarized pp collisions at RHIC
• QCD predictions for spin dependent photonic structure function $g_1^{\gamma }(x,Q^2)$ in the low x region of future linear colliders
• Probing Relativistic Spin Effects in the Nucleon by Means of Drell-Yan Processes
• The $Q^2$ dependence of the measured asymmetry $A_1$: the test of the Bjorken sum rule
• Phenomenological determination of polarized quark distributions in the nucleon
• Waiting for the W and the Higgs
• Octet Quark Contents from SU(3) Flavor Symmetry
• Parton distribution functions and nuclear EMC effect in a statistical model
• PHENIX Spin Program, Recent Results