Date of Award

6-2008

Document Type

Union College Only

Degree Name

Bachelor of Science

Department

Physics and Astronomy

First Advisor

Michael Vineyard

Language

English

Keywords

analysis, determine, photon, acceptance, cross

Abstract

The photoproduction of p0 and h mesons from hydrogen and 3He targets over an incident photon energy range of 0.5 - 1.5 GeV was studied using data from the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. This was part of a systematic study of meson photoproduction from the proton and light nuclear targets to investigate possible nuclear medium modifications of nucleon resonances and meson-nucleon interactions. A preliminary analysis of h cross sections was done using missing mass analysis and the results were compared to known data. Several corrections were then done to account for momentum loss of charged particles, as well as to determine fiducial volumes for charged particles and photons. The final analysis involved reconstructing the neutral mesons from their two-photon decay. Two-photon invariant mass spectra binned in incident photon energy and production angle were fitted to extract yields for p0 and h meson photoproduction. Monte Carlo simulations were also performed to determine the acceptance of the CLAS detector for these reactions. The analysis will be described and the procedures used to extract the yields and determine the acceptance will be discussed. Finally, preliminary cross section results will be presented. We saw an unexpected bump in the cross sections for the p0 at around 50 to 60 degrees. Further study is needed in order to determine whether this bump is due to an unknown phenomenon or an error in our analysis.

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