Dr. Stanislaus, Dr. Gibson-Even
Arts and Sciences
Physics and Astronomy
The Solenoidal Tracker at RHIC (STAR) located at Brookhaven National Laboratory uses longitudinally polarized proton-proton collisions to study the gluon contribution to the known proton spin of ½ h-bar. The relative contributions of the quarks and gluons to the spin of the proton remain uncertain. Using data from the 2013 longitudinally polarized proton-proton collisions we are studying the asymmetry of proton spin dependent production of neutral pions (pi0s) from these collisions. pi0s rapidly (8.5*10 -17 s) decay into 2 photons that are detected by the Endcap Electromagnetic Calorimeter whereby the pi0s can be identified. By comparing the number of pi0s produced when protons collide with different helicities, the asymmetry of pi0 production (ALL ), which can be related to the contribution of the gluon to the spin of the proton, can be measured. The two-photon invariant mass spectrum is reconstructed and then fit using a skewed Gaussian function to represent the pi0 signal and a Chebyshev function to characterize the background. Various checks must be made to authenticate the quality of the data being analyzed. The status of this analysis will be presented.
Nelson, Emily and Wallner, Madison, "Determining A_LL for pi0 production from STAR 2013 Endcap Calorimeter Data" (2022). Summer Interdisciplinary Research Symposium. 116.