First Measurements Of The Polarized Spin Density Matrix Elements Along With A Partial-Wave Analysis For γp→ pω Using CLAS At Jefferson Lab

Abstract

This work presents measurements of the spin density matrix elements for the reaction γp→pω. The data were collected using the CLAS detector in Hall B at Jefferson Lab, from two different datasets, g1c and g8b. The results from the g1c dataset cover the energy range 1720 MeV ≤√s≤ 2470 MeV, and, due to a circularly polarized photon beam, allow access to the ρ3 spin density matrix elements. The results from the g8b dataset cover the energy range 1720 MeV ≤√s≤ 2210 MeV, and, due to a linearly polarized photon beam, allow access to the ρ1 and ρ2 spin density matrix elements. The results presented here include the first measurements, at any energy, of the ρ1−3 elements. Therefore, our results significantly increase the world’s data on ω photoproduction spin dependence. We have also performed a mass-independent partial-wave analysis to determine the dominant resonances involved in ω photoproduction. The addition of polarization information is shown to increase our analyzing power over experiments without polarization information. However, it has not allowed us to determine the mass and width of the resonances involved. It may be necessary to modify the models for non-resonant production to be able to determine those.