Partial Wave Analysis Results for omega Photoproduction and the Search for Missing Resonances

by Mike Williams (Imperial College)

Constituent quark models do a good job of reproducing the spectra of excited mesons; however, they predict the existence of approximately four times as many excited baryon states as have been observed experimentally. Some quark model calculations of baryon decays predict that a number of the so-called missing baryons should couple to omega-N final states. In particular, nearly all of the missing positive parity N* states are expected to have non-negligible couplings to omega-N. Thus, good data on omega photoproduction coupled with a partial wave analysis could provide important new information on light-quark baryons.

Previous experiments have produced cross section measurements with relatively high precision at most production angles; however, precise polarization information has only been measured at very forward angles at higher energies. Theoretical interpretations of these data agree on certain aspects,; however, attempts to extract resonance contributions have obtained conflicting results. Precise polarization information is needed in order to place stringent constraints on the physics interpretation of the data. New data obtained using the CLAS at Jefferson Lab are approximately 200 times more precise than the previous world's data. I will present these measurements and the results of a partial wave analysis performed on the data. Strong evidence for resonance contributions to omega photoproduction has been found.