RUI: Test of Chiral Symmetry via the Primakoff Effect

University Of North Carolina At Wilmington, Wilmington NC

Investigators

Abstract

This project is designed to integrate important contributions to the ongoing research at Jefferson lab with an educational experience for promising undergraduate students. A UNCW group with a team of undergraduate students and one full time faculty member has been actively involved in Jefferson lab research in the past four years. The primary goal of this project is to optimize the undergraduate experience while making important contributions to our understanding of the fundamental properties of QCD at low energy by studying the three neutral light pseudoscalar mesons, pion-zero, eta and eta (eta-prime). This research program consists of several experiments to measure the radiative decay widths and transition form factors of these three particles via the Primakoff Effect. The results of these measurements will have a significant impact on fundamental aspects of QCD. Of particular importance is a more accurate determination of the light quark-mass ratio and the eta-eta mixing angle. The transition form factors of these mesons at very small momentum transfer will provide model-independent extractions of the size of the electromagnetic interaction radii of mesons, and a low energy constant in the chiral Lagrangian. An experiment to measure the pion-zero two-photon decay width was successfully completed in fall 2004. The data analysis is currently in process. The advent of a 12 GeV electron beam at Jefferson Laboratory will make it possible to extend the measurement to the eta and eta particles. The UNCW group will continue working on existing pion-zero data analysis, play a leading role in optimizing the future experimental setup for the eta and eta by Monte Carlo simulation, and make significant contributions to the design and development of a high energy photon tagger and an existing electromagnetic calorimeter (HYCAL) upgrade. The PI will also initiate a new physics effort at Jlab to search for eta-mesic nuclei bound states. This research will engage undergraduate science majors as key contributors. The involvement of undergraduates has become one of the trademarks of the UNCW research group and matches the universitys commitment to provide a high quality undergraduate learning experience.