Pseudoscalar Photoproduction from the Proton
Dr. Michael Dugger
Arizona State University,
Tempe, AZ 85287-1504, USA
Since the proton is made up of quarks, the proton has an excitation
spectrum that can reveal details of the forces between the quarks. In
much the same way that atomic spectroscopy yields information about the
excited states of atoms, baryon spectroscopy explores the excitation
spectra of excited baryons (which includes the proton). The excitation
spectrum of the proton is comprised of many broad overlapping
resonances, which makes investigations of these resonances challenging.
The photoproduction of non-strange pseudoscalar photoproduction
provides an excellent tool in helping deconvolve the spectrum. Since
the beginning of this new millennium, much progress has been made in
measuring pion, h
photoproduction from the proton. In addition to differential
cross section data, there have been a comparatively smaller number of
polarization measurements for meson photoproduction. However, these
polarization measurements, if they exist at all, only cover the energy
range up to about Eg
= 1.5 GeV. I will present exam- ples of
preliminary Jefferson Lab CLAS data on beam asymmetry for the p+,
h and h'
mesons for energies up to about Eg
= 2.0 GeV. I will also discuss how the new measurements, along with
newly taken target polarization data, will be useful in understanding
the structure and excited states of the proton.
This work is supported by the U.S. National Science Foundation.