Neutral Pion Analysis in Longitudinally Polarized proton+proton Collisions

Authors

Taegyun Kim, Valparaiso UniversityFollow

Faculty Sponsor

Dr. Adam Gibson-Even

College

Arts and Sciences

Discipline(s)

Physics

Presentation Type

Oral Presentation

Symposium Date

Spring 5-4-2017

Abstract

Beyond the valence quark's spin contribution to the total spin of a proton, gluon and sea quark contributions are becoming clear as well. For proton+proton collisions at a center of mass energy of 510 GeV, neutral pion production is dominated by gluon-gluon and gluon-quark scattering. An avenue to constrain the gluon polarization is the asymmetry, A_LL, in the production of neutral pions from collisions of longitudinally spin-polarized proton beams. Our experiment was performed with the STAR detector at the Relativistic Heavy Ion Collider (RHIC), unique for its ability to collide spin-polarized proton beams. The Endcap Electromagnetic Calorimeter (EEMC) of the STAR detector with its pseudorapidity (η) range between 1.09 and 2.00 and full azimuthal coverage measures energies of photons from π⁰ decays. We consider the invariant mass of all photon pairs in the EEMC as we identify π⁰ candidates. We will present the current status of the analysis of the π⁰ A_LL as measured by the EEMC at STAR in 2012 data with center-of-mass energy of 510 GeV.

Recommended Citation

Kim, Taegyun, "Neutral Pion Analysis in Longitudinally Polarized proton+proton Collisions" (2017). Symposium on Undergraduate Research and Creative Expression (SOURCE). 663.
https://scholar.valpo.edu/cus/663