On the measurability of the structure function $g_1(X,Q^2)$ in $ep$ collisions at HERA

Abstract

The possibility is investigated to measure the polarized structure function $g_1(x,Q^2)$ in the collider mode of HERA operating with a polarized lepton and proton beam. The $x$ dependence of $g_1$ can be measured at a statistical precision of $\sim 20\%\mathrm{to}80\%$ in the range $0.0005<x<0.5$ correlated to virtualities $15<⟨Q^2⟩<3500{\text{GeV}}^2$ at beam polarizations ${\lambda }_p\sim {\lambda }_e=0.8$ and ${\mathcal{L}}_{int}=60{\text{PB}}^{-1}$. At a low energy option, $E_p=300\text{GeV}$, the statistical accuracy improves to values of $\sim 15\%\mathrm{to}50\%$ in the range $10^{-3}<x<0.5$ and $10<Q^2<800{\text{GeV}}^2$.

Comments: 13 pages uuencoded ps-file, 3 figures changed, 1 figure added