|
|
Matt Shaw working on the Crystal Ball
|
For the past several years, ACU has been heavily involved in the Crystal Ball Experiments 913 and 958, which ran at Brookhaven National Laboratory. The goal of these experiments is to study the masses, widths, and decay modes of baryon resonances from π– p interactions. Studying these interactions can give us a better understanding of quark/gluon configurations and of the hadronic force as it is currently modeled in quantum chromodynamics.
The Crystal Ball detector is a highly segmented multi-photon spectrometer composed of 672 optically isolated NaI(Tl) crystals that detect individual gammas. When a pion interacts with our proton target, we need to detect all the end products in order to reconstruct exactly what happened. Since the Crystal Ball is a spherical detector, it covers almost 4π steradians and allows us to “see” everything that occurs inside it.
ACU students have been very involved in E913 since its beginning, and they have made many significant contributions in the experiments’ design, construction, running, and data analysis. ACU students were very involved in calibrating the Crystal Ball and testing the veto barrel. Using GEANT-based Monte Carlo computer simulations, students have improved beam normalizations, performed momentum calibrations, analyzed time of flight, and designed one of the critical counters for E958. As we are nearing the publication of E913, analysis of E958 is just beginning, and there are lots of exciting opportunities for new students to get involved.
