Speaker
Mark Jones
(Jefferson Lab)
Description
The Spin Asymmetries of the Nucleon Experiment (SANE)
ran at Jefferson Lab and measured double spin asymmetries for inclusive
electron scattering on a proton target which was polarized parallel and perpendicular to the polarized electron beam. SANE used a large acceptance detector package to
measured the proton's polarized spin structure functions $g_1$ and $g_2$ in a range of Bjorken $x$, $0.3 < x < 0.8$, and a range of $Q^2$ from to $1.8 GeV^2$ up to $6.5 GeV^2$. Complementary measurements were made simulataneously with the standard Hall C small acceptance High Momentum Spectrometer. Within the operator
product expansion framework, the twist-3 matrix element, $d_2^p=\int
x^2(2g_1+3g_2)dx$, is proportional to the average color Lorentz force on the quark (moving in the infinite momentum frame) the instant after being struck by a virtual photon. In addition to
presenting the latest results on spin structure functions, we will discuss the physics impact and Q$^2$ dependence of $d_2^p$.
Primary author
Mark Jones
(Jefferson Lab)
