Theory

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Inclusive Scattering

W

Semi-Inclusive Scattering

Quark distribution Functions

Unpolarized

Polarized

The inclusive double polarization asymmetries [math]A_N[/math] can be written in terms of polarized [math]\triangle q_v (x)[/math] and unpolarized [math] q_v (x)[/math] valence quark distributions,


[math]A_{1, p}[/math]I = [math]\frac {4\triangle u_v (x) + \triangle d_v (x)} {4 u_v (x) + d_v (x)} [/math]
[math]A_{1, n}[/math]I = [math]\frac {\triangle u_v (x) + 4\triangle d_v (x)} {u_v (x) + 4d_v (x)} [/math]


The semi-inclusive pion electro-production asymmetries can be written in terms of the valence quark distributions in the following way
[math]A_{1, p}[/math][math]\pi^+ - \pi^-[/math] = [math]\frac {4\triangle u_v (x) - \triangle d_v (x)} {4 u_v (x) - d_v (x)} [/math]


[math]A_{1,2H}[/math][math]\pi^+ - \pi^-[/math] = [math]\frac {\triangle u_v (x) + \triangle d_v (x)} { u_v (x) + d_v (x)} [/math]


where

[math]A[/math][math]\pi^+ - \pi^-[/math] =[math]\frac {\sigma^\pi^+ - \pi^- _\uparrow \downarrow} {1} [/math]