Latest Results on $g_1$ and $g_2$ at high $x$

Abstract

Recent progress from Jefferson Lab has significantly improved our understanding of the nucleon spin structure in the high-$x$ region. Results of a precision measurement of the neutron spin asymmetry, $A_1^n$, in the high-$x$ (valence quark) region are discussed. The up and down quark spin distributions in the nucleon were extracted. $A_2^n$ was also measured. The results were used, in combination with existing data, to extract the second moment, $d_2^n$. Preliminary results on $A_1^p$ and $A_1^d$ in the high-$x$ region have also become available. Finally, the results of a precision measurement of the $g_2$ structure function to study higher twist effects will be presented.