Neutral Pion Asymmetries at Intermediate Pseudorapidity in Transversely Polarized p + p Collisions at √s = 200 GeV

Faculty Sponsor

Dr. Jim Drachenberg


Arts and Sciences



Presentation Type

Poster Presentation

Symposium Date

Summer 7-31-2014


Among the unanswered questions pertaining to nucleon spin physics is the origin of large azimuthal asymmetries (AN ) found in π0 s produced at forward pseudorapidity, η, from high-energy transversely polarized p + p collisions. One possible explanation is offered by twist-3 parton distribution and fragmentation functions. In order to test these and other mechanisms, it is important to study how the asymmetry changes over a range of pion kinematics. The STAR Endcap Electromagnetic Calorimeter (EEMC) is the only RHIC detector with the ability to study AN for π0 s in the kinematic range available at intermediate pseudorapidity, 0.8 ≤ η ≤ 2.0. STAR recently published the first measurement of AN for π 0 s at intermediate pseudorapidity using data collected in 2006 with collision energy √s = 200 GeV. In 2012 STAR collected a high-statistics dataset with transverse beam polarization at √s = 200 GeV. This offers over a five-fold increase in integrated luminosity relative to the 2006 dataset and a chance to enhance the precision of the previous results. The primary objective of this study is to determine the quality of the data from 2012 and to estimate the final statistical uncertainty. Preliminary results from this study indicate a significant improvement over the 2006 results.

Biographical Information about Author(s)

Samuel Brandt will be a sophomore physics and mathematics major next year. He became interested in physics while in high-school. Aside from physics, he enjoys making and listening to music, bicycling, volunteering, and thinking about philosophy. He hopes to go onto graduate school in physics.

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