Measurement of the double spin asymmetry A$_{LL}$ from inclusive charged pion production in polarized p+p collisions at 200 GeV.

A primary goal of the RHIC Spin program is the measurement of the polarized gluon distribution function $\Delta g$, which can be obtained from a global analysis incorporating measurements of the double spin asymmetry A$_{LL}$ in various final state channels of polarized p+p collisions. Final states with large production cross sections such as inclusive jet and hadron production are analyzed as the program moves towards the measurement of A$_{LL}$ in the theoretically clean channel of prompt photon production. The channels $\vec {p}+\vec {p}\to \pi ^{+/-}+X$ are unique in that the ordering of the measurements of A$_{LL}$ in these two channels is sensitive to the sign of $\Delta g$. Moreover, the STAR experiment has already established the procedure for the identification of charged pions and the calculation of their production cross-sections over a broad kinematic range. This contribution will present progress towards measurements of A$_{LL}$ extracted from inclusive charged pion yields in the transverse momentum region $2$<$p_{T}$<$12$ GeV/c. These yields were obtained from $\sim $3 pb$^{-1}$ of data taken by STAR at $\sqrt s $=200 GeV in 2005.