Search

The GlueX experiment will search for exotic mesons produced by 9 GeV linearly polarized photons from the upgraded CEBAF machine. It is critical to detect and measure the four-momenta of all the charged particles and photons resulting from the decays of the mesons. The solenoid-based detector system includes tracking detectors and calorimeters. The Forward Drift Chamber, FDC, consists of 24 circular planar drift chambers of 1m diameter. Additional cathode readout is required to achieve efficient pattern recognition. The detection of photons by the electromagnetic calorimeters imposes constraints on the amount of material used in the FDC. The specific features of the detector and the readout electronics will be described. Results from the tests of the full scale prototype will be presented, as well. [ABSTRACT FROM AUTHOR]

The article discusses experimental validation of the Born approximation in the measurements of proton form factor using polarization method. The experiment aimed to study effects beyond the Born approximation using the polarization method. Under the study, the proton longitudinal polarization was measured separately and can be compared independently to the Born approximation prediction.

Significant theoretical and experimental efforts have been made over the past 7 years aiming to explain the discrepancy between the proton form factor ratio data obtained at JLab using the polarization method and the previous Rosenbluth measurements. Preliminary results from the first high precision polarization experiment dedicated to study effects beyond Born approximation will be presented. The ratio of the transferred polarization components and, separately, the longitudinal polarization in ep elastic scattering have been measured at a fixed Q2 of 2.5 GeV2 over a wide kinematic range. The two quantities impose constraints on the real part of the ep elastic amplitudes. [ABSTRACT FROM AUTHOR]