at Jefferson Lab*

Serving as a precision measurement of the neutron spin structure function g₂ and first time evaluation of the d₂ at constant Q² for Q² > 1 GeV²/c², the expeiment E12-06-121 was successfully completed in Hallc C of Jefferson Lab. While g₂ contains information of quark-gluon correlations, d₂, which is a linear combination of g₁ and g₂, is related to "color polarizabilities" and color Lorentz force acting on stuck quark. This experiement utilized the longitudinally polarized 10.4 GeV electron beam and a polarized helium-3 target which can be polarized both longitudinally and transversely. Aslo the large acceptance of the Super High Momentum Spectrometer (SHMS) combined with High Momentum Spectrometer (HMS) allows the measurment over nearly constan Q2 in a very broad x_Bj region. This work will present an overview of the experiment and preliminary results from data analysis.