Measurement of the High Energy Two-Body Deuteron Photodisintegration Differential Cross Section


Book Description

The first measurements of the d(gamma, p)n differential cross section at forward angles and photon energies above 4 GeV were performed at the Thomas Jefferson National Accelerator Facility (JLab). The results indicate evidence of an angular dependent scaling threshold. Results at theta{sub cm} = 37{sup o} are consistent with the constituent counting rules for E{sub gamma}H" 4 GeV, while those at 70{sup o} are consistent with the constituent counting rules for E{sub gamma} H" 1.5 GeV.




High Energy Two-Body Deuteron Photodisintegration


Book Description

The differential cross section for two-body deuteron photodisintegration was measured at photon energies between 0.8 and 4.0 GeV and centerofmass angles [theta]cm =37°, 53°, 70°, and 90° as part of CEBAF experiment E89012. Constituent counting rules predict a scaling of this cross section at asymptotic energies. In previous experiments this scaling has surprisingly been observed at energies between 1.4 and 2.8 GeV at 90°. The results from this experiment are in reasonable agreement with previous measurements at lower energies. The data at 70° and 90° show a constituent counting rule behavior up to 4.0 GeV photon energy. The 37° and 53°g data do not agree with the constituent counting rule prediction. The new data are compared with a variety of theoretical models inspired by quantum chromodynamics (QCD) and traditional hadronic nuclear physics.










Photodisintegration of the Deuteron at High Energy


Book Description

Measurements of the angular distribution for the?d→+pn reaction were performed at SLAC for photon energies between 0.7 and 1.8 GeV (experiment NE8) and between 1.6 and 4.4. GeV (experiment NE17). The final results for experiment NE8 will be presented, but only preliminary results for NE17 will be discussed. The data at?{sub cm} = 90° appear to follow the constituent counting rules. The angular distribution at high photon energies exhibit large values of the cross section at forward angles. There is evidence that the cross section may also be large at backward angles and high energies.




An Absolute Measurement of the Photodisintegration Differential Cross Section of the Deuteron


Book Description

We have measured the absolute $rmsp2H(gamma,p)n$ angular distribution using the Illinois LASA detector at the Saskatchewan Accelerator Laboratory's tagged photon facility. Using 40 to 90 MeV photons, we aimed to measure the differential cross section with a statistical precision of typically 5% in angular bins of $3spcirc$ and energy bins of 2 MeV. Although our measurement achieved this goal, the contribution of systematic errors was larger than anticipated and thus compromised the utility of this result. Without these systematic errors, this measurement (when combined with the world data set) would have provided an extensive experimental data set with an accuracy which was better than the scatter between the various theoretical calculations for the interaction. Refinements to the treatment of the interaction would then have been testable. In particular, because the shape of the angular distribution in this energy regime is sensitive to meson exchange currents, it would have been possible to investigate the methods for incorporating these currents into calculations.




High Energy Photodisintegration of the Deuteron


Book Description

A review of both the data base and current model predictions for the observables of the deuteron photodisintegration reaction, [gamma]d → p{sub n} is presented. Recent cross section and polarization measurements at Jefferson Lab are shown and discussed. A few conclusions are attempted.