1998/11/02 by Eschrich, Ivo
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex)
paper · doi:10.48550/arxiv.hep-ex/9811003
The charge radii of Sigma- and pi- have been determined by direct elastic scttering on shell electrons. The measurement was performed in the framework of the SELEX (E781) charm hadroproduction experiment at Fermilab which employs a 600 GeV/c high-intensity Sigma-/pi- beam and a 3-stage magnetic spectrometer covering 0.1 <= xF <= 1.0. Scattering angles and momenta of both hadron and electron were measured with high precision using silicon microstrip detectors, thus allowing for a segmented solid target. Two TRDs provided full particle identification. A preliminary result for the Sigma- charge radius for a four-momentum transfer squared of 0.03 GeV2/c2 <= Q2 <= 0.16 GeV2/c2 will be reported. In a parallel analysis the pi- charge radius has been determined for 0.03 GeV2/c2 <= Q2 <= 0.2 GeV2/c2, and is found to be consistent with previous experiments.