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Author Knapp, E. A. ♦ Kenney, R. W. ♦ Perez-Mendez, V.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword PHYSICS AND MATHEMATICS ♦ ANGULAR DISTRIBUTION ♦ BACKGROUND ♦ CROSS SECTIONS ♦ DECAY ♦ EFFICIENCY ♦ ENERGY RANGE ♦ HYDROGEN ♦ LIQUIDS ♦ MEASURED VALUES ♦ NUCLEONS ♦ PHOTONS ♦ PHOTOPRODUCTION ♦ PIONS ♦ POSITRONS ♦ SYNCHROTRONS ♦ TARGETS
Abstract An accurate measurement of the differential cross section for the photoproduction of positive pions from protons has been made at the Berkeley synchrotron for photon energies of 260 and 290 Mev. The mesons were produced in a thin-walled liquid-hydrogen target, and the meson-detection apparatus utilized the characteristic decay of the pion. The measurements were done in two steps, from 0 to 50 deg with equipment specifically designed to reduce a very high forward-angle positron background, and from 30 to 160 deg with equipment whose efficiency and solid angle could be accurately determined. The abrupt flattening of the observed cross section in the region forward of 40 deg is due to photoelectric ejection'' of pions from the cloud surrounding the nucleon. The results are compared to the theory of photoproduction derived from the dispersion relations, and the agreement is satisfactory within the limitations of the theory. (auth)
ISSN 0031899X
Educational Use Research
Learning Resource Type Article
Publisher Date 1959-04-15
Publisher Department Univ. of Calif., Berkeley
Journal Physical Review
Volume Number 114
Organization Univ. of Calif., Berkeley


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