K. Beard

The CLAS Forward Electromagnetic Calorimeter

The CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab utilizes six iron-free superconducting coils to provide an approximately toroidal magnetic field. The six sectors are instrumented individually to form six independent spectrometers. The forward region (8deg < (theta) < 45deg) of each sector is equipped with a lead-scintillator electromagnetic sampling calorimeter (EC), 16 radiation lengths thick, using a novel triangular geometry with stereo readout. With its good energy and position resolution, the EC is used to provide the primary electron trigger for CLAS. It is also used to reject pions, reconstruct pi-0 and eta decays and detect neutrons, This paper treats the design, construction and performance of the calorimeter.

Calibration of the polarimeter POMME at proton energies between 1.05 and 2.4 GeV

Abstract We report a new calibration of the polarimeter POMME for energies between 1.05 and 2.40 GeV using polarized proton beams at the Laboratoire National Saturne. A 16 parameter and a new 14 parameter empirical formula have been used to fit both the angular and energy dependencies of the inclusive proton-carbon analyzing power data between 0.80 and 2.40 GeV. Both fits have very good chi-square, 1.20 per degree of freedom for the former, and 1.05 for the latter. The parameters from these fits can be used to predict the angular distribution of the pC analyzing power at any energy within the energy range of the fits.

Cross sections for the {gamma}p{yields}K*{sup 0}{sigma}{sup +} reaction at E{sub {gamma}}=1.7-3.0 GeV

Differential cross sections for the reaction {gamma}p{yields}K*{sup 0}{sigma}{sup +} are presented in the photon energy range of 1.7 to 3.0 GeV. The K*{sup 0} was detected by its decay products, K{sup +}{pi}{sup -}, in the Continuous Electron Beam Accelerator Facilitys large acceptance spectrometer (CLAS) detector at the Thomas Jefferson National Accelerator Facility. These data are the first K*{sup 0} photoproduction cross sections ever published over a broad range of angles. Comparison with a theoretical model based on the vector and tensor K*-quark couplings shows good agreement with the data, except at forward angles, suggesting that the role of scalar {kappa} meson exchange should be investigated.Differential cross sections for the reaction γp→K*0Σ+ are presented in the photon energy range of 1.7 to 3.0 GeV. The K*0 was detected by its decay products, K+π−, in the Continuous Electron Beam Accelerator Facilitys large acceptance spectrometer (CLAS) detector at the Thomas Jefferson National Accelerator Facility. These data are the first K*0 photoproduction cross sections ever published over a broad range of angles. Comparison with a theoretical model based on the vector and tensor K∗-quark couplings shows good agreement with the data, except at forward angles, suggesting that the role of scalar κ meson exchange should be investigated.