Measurement of the Double Longitudinal Spin Asymmetry for Hadron Production in 200 GeV Polarized p+p Collisions at RHIC

A primary goal of the STAR spin physics program at RHIC is the measurement of the gluon polarization, $\Delta g$, in the proton. The STAR detector, with its large-acceptance tracking and calorimetry, provides a uniquely suited environment for asymmetry measurements in a number of different final-state channels in polarized p+p collisions such as inclusive jet production, charged and neutral pion production. These asymmetries will provide important contributions to a global analysis of $\Delta g$. We present here the most recent measurements of the double longitudinal spin asymmetry ($A_{LL}$) for the production of charged and neutral pions at mid-rapidity. These asymmetries are compared to NLO pQCD calculations for different gluon polarization scenarios and are used to provide constraints on $\Delta g$. Charged pions are of particular interest as they are sensitive to the sign of $\Delta g$. Results and continuing analyses are presented from RHIC runs 5 and 6.