RUI: Studying the Strong Nuclear Force at Augustana University

Augustana University Association, Sioux Falls SD

Investigators

Abstract

This award continues the scientific program and laboratory at Augustana University in Sioux Falls, South Dakota devoted to the study of the strong nuclear force, the force responsible for binding protons and neutrons in nuclei. The program's focus is to understand the gluons, particles exchanged through the strong force interaction, in the nucleus. Understanding the binding of nuclei by their gluon content directly explores the matter around us and within us at the most fundamental level. This program will be carried out in two ways. First, current data from the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory will be analyzed. Second, a laboratory that will test silicon photomultiplier (SiPM) detectors for the next-generation experiment, sPHENIX is being built. The SiPMs are low-cost, low-power usage light collection devices with multiple applications in science and industry. Students will help develop and implement tests for a portion of the 125,000 SiPMs for the sPHENIX detector. This program in strong nuclear physics is the first of its kind in South Dakota. It will provide those in the state and the region access to studying this physics where they have had little opportunity. The project will fund research for undergraduates studying both physics and pre-engineering. The educational benefits for the students will be broad. Students will gain practical skills in computer programming, analysis of large data sets, electrical engineering application, and mechanical engineering design just to name a few. These are transferable skills to many areas of interest to the students, the state, and the nation. Those interested in engineering will benefit from the detector testing and development that will be done on site. Students will participate in weekly collaboration meetings, present at national conferences, and visit collaborating institutions. Such opportunities will build their communication skills, grow their profession network, put them in contact with potential graduate schools, and prepare them for the 21st-century technical jobs. An outstanding question in strong-force physics is the behavior of gluons in a nucleus at low momentum fraction. This award continues work by the PI and undergraduates to study this issue in two ways. First, the analysis and determination of the azimuthal correlations between pi-0 mesons and/or between pi-0 mesons and charged hadrons in d-Au collisions recorded by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) in 2016 is proposed. These correlations will utilize the newest sub-detector of PHENIX, the Muon Piston Calorimeter Extension (MPC-EX), this detector is a silicon-tungsten pre-shower detector with high segmentation that can separate photons from pi-0 decays with energies less than 80 GeV. The MPC + MPC-EX is located at a pseudorapidity between three and four, with the positive pseduorapidity defined as the Au-going direction. The pair rate and pair correlation shapes should yield insights to the number and kinematics of low momentum fraction gluons in the nucleus. Second, the group is transitioning from PHENIX to sPHENIX, a new collaboration building a next-generation heavy ion detector in the PHENIX interaction region, which will take advantage of high-luminosity RHIC running beyond 2020. Augustana is committed to performing a portion of the silicon photomultiplier (SiPM) testing. Both electromagnetic and hadronic calorimeter light collection will be done with approximately 125,000 SiPMs. Augustana will help design and implement the testing.