Longitudinal Double-Spin Asymmetries for Intermediate Rapidity Inclusive $\pi^0$ Production from Polarized $pp$ Collisions at $\sqrt{s}$ = 200 GeV at STAR

We present an update of the analysis towards a new measurement of the longitudinal double-spin asymmetry $A_{LL}$ for neutral pions ($\pi^0$'s) reconstructed in the STAR Endcap Electromagnetic Calorimeter (EEMC) from polarized proton-proton collisions at $\sqrt{s}=200$ GeV with data taken in 2009. The EEMC is optimized for measurement of $\pi^0$'s, with full azimuthal coverage for $1.086 < \eta < 2.0$ and a fine granularity, scintillator-based shower maximum detector to identify $\pi^0$'s signature di-photon decay. Neutral pion $A_{LL}$ is sensitive to the polarized gluon distribution function $\Delta g(x)$, as quark-gluon scattering is the dominant subprocess for $\pi^0$ production in the EEMC region. In the more forward pseudorapidity region of the EEMC ($\eta > 1.3$), where inclusive jet measurements are compromised due to increased charged-particle tracking inefficiencies, $\pi^0$'s can be reconstructed accurately, allowing us to probe lower values of partonic momentum fraction $x$, where $\Delta g(x)$ is poorly constrained.