References - Bogoliubov Laboratory of Theoretical Physics - JINR

g 3 A =Δuv(Q 2 ) − Δdv(Q 2 ),
g 8 A =Δuv(Q 2 )+Δdv(Q 2 ).
(5)
=0.579 ± 0.025 [8]. From
The experimental values are g3 A =1.2573 ± 0.0028 and g8 A
the stated values for Δuv and Δdv we obtain g3 A =1.240 − 1.253 which accommodates the
experimental value with an accuracy of 2%. The octet coupling constant, g8 A ,isequivalent
to valence quark polarization in our model and its value is vary between 0.39 - 0.41. this
result is in very good agreement with the newly COMPASS results [7]. The value for a8 is
substantially different from 0.579 ± 0.025, a result that seems confirmed by the emerging
experiments. The COMPASS collaboration provided direct information about the valence
quark polarization [7]:
� 0.7
Γv(xmin) = [δuv(x)+δdv(x)] dx, (6)
δuv(x)+δdv(x) = 36
5
g d 1 (x)
xmin
(1 − 1.5ωD) −
�
2(δū(x)+δ ¯ d(x)) + 2
5 (δs(x)+δ¯s(x))
�
. (7)
With precise measurement of gd 1 (x), COMPASS obtained the valence quark polarization
for the full measured range of x
x δu v+x δ dv
0.5
0.45
0.4
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
-0.05
-0.1
-0.15
-0.2
10 -2
Γv(0.006