Q2 evolution of 3He spin structure functions moments

Sum rules offer the opportunity to test our understanding of the structure of a system on general grounds. In this paper we investigate the 3He nucleus using the Gerasimov-Drell-Hearn and Burkhardt-Cottingham sum rules. We have previously used the polarized 3He target measurements to extract the neutron spin structure, our goal here is to investigate rather the 3He nucleus. We have determined for the first time the Q2 evolution of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\Gamma_1(Q^2)=\int_0^{1} g_1(x,Q^2) dx$\end{document} and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\Gamma_2(Q^2)=\int_0^1 g_2(x,Q^2) dx$\end{document} for 3He in the range 0.1 GeV2 ≤ Q2 ≤ 0.9 GeV2 with good precision. Γ1(Q2) displays a smooth variation from high to low Q2. However, we do not see yet its expected turnover toward the real photon limit value. On the other hand the Burkhardt-Cottingham sum rule holds at all measured Q2s within uncertainties due mainly to cancellations between the elastic, quasielastic and the Δ(1232) resonance contributions.