Determining Gluon Contribution to Proton Spin with STAR 2015 Endcap Electromagnetic Calorimeter Data

Longitudinally polarized protons are collided in the Solenoidal Tracker at RHIC (STAR) located at Brookhaven National Laboratory to study the gluon spin contribution to the spin of the proton. Refining our knowledge of the gluon spin contribution to the proton's spin will help us solve the proton spin puzzle and is one significant goal of the STAR collaboration. This study analyzes the data from 2015 longitudinally polarized proton-proton collisions (√s = 200 GeV) and the resulting neutral pions (π⁰) that are created. The π⁰s decay almost instantaneously (~10^-16 s) into two photons that can be detected with STAR's Endcap Electromagnetic Calorimeter (EEMC, 1.09 < η < 2.00). By analyzing the π⁰s that are produced we can calculate the spin-dependent asymmetry, A_LL, of the π⁰ which is related to the gluon contribution to the spin of a proton. We have analyzed the 2015 data to form photon and π⁰ candidates. To ensure quality data for the eventual A_LL analysis, we monitor distributions such as the reconstructed π⁰ mass and the number of EEMC towers hit per event. We will present the status of the 2015 EEMC π⁰ reconstruction and quality assurance effort.