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FIZIKA B 13 (2004) 1, 115 - 126
 
PRODUCTION OF PSEUDOSCALAR MESONS
W. J. BRISCOE, R. A. ARNDT, I. I. STRAKOWSKY and R. L. WORKMAN
The Center for Nuclear Studies and Department of Physics,
The George Washington University, Washington, D.C. 20052, USA
Received 18 September 2003; Accepted 26 April 2004
Online 16 July 2004
Experiments that study the hadronic and electromagnetic production of the pseudoscalar
mesons - pions, etas and kaons, contribute to our knowledge of the properties of baryon
and hyperon resonances. Fixed-target programs at hadronic facilities, such as BNL-AGS,
have been phased out. However, the availability of modern experimental facilities with
pseudo-monochromatic or tagged medium-energy photon beams at GRAAL, SPring-8, Bonn, Mainz,
and Jefferson Lab, together with LEGS, Max-Lab, and HIGS at lower energies, are beginning
to produce high-quality results. These new data have smaller statistical uncertainties and
better understood systematic uncertainties, than those obtained at the older
bremsstrahlung facilities, for measurements of differential and integrated cross sections,
as well as polarization and asymmetry. Experimental results are compared with the
predictions of QCD-based approaches, such as the lattice-gauge calculations of baryon
properties, and chiral perturbation theory applied to threshold photoproduction, and are
essential to the performance of partial-wave analyses (PWA). These PWA studies are less
model dependent than in the past, and are used in coupled-channels calculations that
incorporate unitarity dynamically, and combine results from hadronic reaction channels
with electromagnetic processes. This approach is necessary to extract resonance properties
and may lead to the discovery of the "missing resonances" predicted by a number
of different QCD-inspired calculations. We discuss recent experimental and
phenomenological results for single and double pseudoscalar meson hadronic and
photoproduction channels with emphasis on the JLab Hall B and the BNL/AGS Crystal Ball
programs.
PACS numbers: 14.20.Gk, 13.75.Gx, 11.80.Et, 25.20.Lj
UDC 539.126
Keywords: single-pion photoproduction, pN elastic
scattering, baryon and hyperon resonances, electromagnetic and hadronic probes
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