Constraint on Delta g(x) from π⁰ production at RHIC

We determine the polarized gluon distribution \Delta g(x) by a global analysis using current DIS and \pi^0 asymmetry data. The \pi^0 data from RHIC-Spin experiments provide a strong constraint on \Delta g(x), so that its uncertainty is reduced. However, a sign problem appears in the analysis using \pi^0 data, which means that positive and negative distributions are allowed for \Delta g(x). These two types of solutions are discussed.