Determining $\pi^0$ $A_{LL}$ from STAR 2012 Endcap Calorimeter Data

The Solenoidal Tracker at RHIC (STAR) located at Brookhaven National Laboratory in New York uses longitudinally polarized proton-proton collisions to determine the gluon contribution to the spin of the proton. One analysis of the 2012 data set, at a proton-proton center of mass energy of 510 GeV, studies the production of neutral pions ($\pi^0$) which immediately ($\sim$ 10$^{-16}$s) decay into two photons. The neutral pion asymmetry, $A_{LL}$, can be determined through data collected by the Endcap Electromagnetic Calorimeter (EEMC). The EEMC, positioned in an intermediate pseudorapidity range of 1 $<$ $\eta$ $<$ 2, is able to measure the energy and position of each photon’s electromagnetic shower. By using this information as well as the angle between the photons, the two-photon invariant mass can be reconstructed. The invariant mass spectra are fitted using a skewed Gaussian plus a background function to determine the total number of $\pi^0$s present. The $\pi^0$ asymmetry is calculated from the number of $\pi^0$s in collisions with different polarization directions of the colliding proton beams. The status of the measurement of $A_{LL}$ of the $\pi^0$s as a function of the transverse momentum, $p_{T}$ , of the $\pi^0$ will be presented.