Gluon Spin Contribution to The Nucleon Spin

2010 ◽  
Vol 207-208 ◽  
pp. 57-60
Author(s):  
Firooz Arash ◽  
Abolfazl Shahveh ◽  
Fateme Taghavi-Shahri
2005 ◽  
Vol 20 (08n09) ◽  
pp. 1923-1926 ◽  
Author(s):  
ALI N. KHORRAMIAN ◽  
A. MIRJALILI ◽  
S. ATASHBAR TEHRANI

In this paper we calculate spin dependence of parton distributions and proton structure function. The polarized valon distributions in a proton and the polarized parton distributions inside the valon are necessary to obtain the polarized parton distributions in a proton. The results of our calculations for the proton structure function, [Formula: see text] are in good agreement with the available experimental data. We obtain the spin contribution and angular momentum of the valons to the proton.


2015 ◽  
Vol 24 (10) ◽  
pp. 1550077 ◽  
Author(s):  
Wei Zhu ◽  
Jianhong Ruan

This paper contains three parts relating to the nucleon spin structure in a simple picture of the nucleon: (i) The polarized gluon distribution in the proton is dynamically predicted starting from a low scale by using a nonlinear quantum chromodynamics (QCD) evolution equation — the Dokshitzer–Gribov–Lipatov–Altarelli–Paris (DGLAP) equation with the parton recombination corrections, where the nucleon is almost consisted only of valence quarks. We find that the contribution of the gluon polarization to the nucleon spin structure is much larger than the predictions of most other theories. This result suggests that a significant orbital angular momentum of the gluons is required to balance the gluon spin momentum. (ii) The spin structure function [Formula: see text] of the proton is studied, where the perturbative evolution of parton distributions and nonperturbative vector meson dominance (VMD) model are used. We predict [Formula: see text] asymptotic behavior at small x from lower Q2to higher Q2. The results are compatible with the data including the early HERA estimations and COMPASS new results. (iii) The generalized Gerasimov–Drell–Hearn (GDH) sum rule is understood based on the polarized parton distributions of the proton with the higher twist contributions. A simple parameterized formula is proposed to clearly present the contributions of different components in the proton to [Formula: see text]. The results suggest a possible extended objects with size 0.2–0.3 fm inside the proton.


1998 ◽  
Vol 431 (3-4) ◽  
pp. 405-409 ◽  
Author(s):  
V. Barone ◽  
T. Calarco ◽  
A. Drago
Keyword(s):  

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