Accession Number:

AD0618661

Title:

PION-PAIR PHOTOPRODUCTION BELOW 1 BEV,

Descriptive Note:

Corporate Author:

STANFORD UNIV CALIF HIGH ENERGY PHYSICS LAB

Personal Author(s):

Report Date:

1965-05-01

Pagination or Media Count:

17.0

Abstract:

Measurements of the differential cross-section for the reaction gamma p to pion - pion p have been made at several angles for photon energies in the range 550-1000 MeV, using the Stanford Mark III linear accelerator. The pion- were detected and momentum analyzed using a 90 degree magnetic spectrometer. It was found that the reaction was dominated by the pseudo-2-body photoproduction gamma p to pion - N 1238 especially near the threshold for this process. At low momenta, the pion- were identified by range. At high momenta 250 MeVc, the contaminating electrons were eliminated by using a lead and scintillation-counter sandwich system. The yields of both pion - and pion off hydrogen were measured and the normalization was obtained by comparing with the known cross-sections for gamma p to pion n. Computer calculations of the shapes of the yield curves expected from 2-body and 3-body production enabled the data to be separated into the two possible states gamma p to pion - N 1238 and gamma p to pion - pion p. Angular distributions and total cross-sections are presented. Author

Subject Categories:

Distribution Statement:

APPROVED FOR PUBLIC RELEASE