Photoproduction of Positive Pions in Hydrogen-Magnetic Spectrometer Method

R. L. Walker; J. G. Teasdale; V. Z. Peterson; J. I. Vette

doi:10.1103/PhysRev.99.210

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Photoproduction of Positive Pions in Hydrogen-Magnetic Spectrometer Method

R. L. Walker, J. G. Teasdale, V. Z. Peterson, and J. I. Vette

California Institute of Technology, Pasadena, California

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Phys. Rev. 99, 210 – Published 1 July, 1955

DOI: https://doi.org/10.1103/PhysRev.99.210

Abstract

Positive pions produced in a cold, high-pressure hydrogen gas target by the 500-Mev bremsstrahlung of the CalTech synchrotron, have been analyzed by a large magnetic spectrometer. The photoproduction cross section has been measured as a function of photon energy at laboratory angles of 12.5°, 30°, 51°, 73°, 104°, 140°, and 180°. The energy region covered depends somewhat on the angle, but is typically from 200 to 470 Mev. From these excitation curves the angular distribution of the photopions in the center of momentum system is obtained for various photon energies, and these angular distributions are analyzed in the form $A + B cos θ + C {cos}^{2} θ$ . The angular distribution has a backward maximum at low energies and a forward maximum at high energies, the coefficient $B$ changing sign at about 340 Mev. The total cross section shows a striking maximum near 290 Mev, of magnitude 205× $10^{- 30}$ ${cm}^{2}$ , and falls off above the maximum faster than $λ^{2}$ .

References (34)

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H. A. Bethe and F. de Hoffmann, Mesons and Fields (Row, Peterson, and Company, Evanston), Vol. 2
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Omitted endnote
Walker, Teasdale, and Peterson, Phys. Rev. 92, 1090(A) (1953)
E. Segrè, K. T. BainbridgeExperimental Nuclear Physics (John Wiley and Sons, Inc., New York, 1953), Chapter by , pp. 576 ff
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Omitted endnote
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Omitted endnote
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[c1] Anderson, Fermi, Martin, and Nagel, Phys. Rev. 91, 155 (1953)

[c2] H. A. Bethe and F. de Hoffmann, Mesons and Fields (Row, Peterson, and Company, Evanston), Vol. 2

[c3] de Hoffmann, Metropolis, Alei, and Bethe, Phys. Rev. 95, 1586 (1954)

[c4] H. A. Bethe and F. de Hoffmann, Phys. Rev. 95, 1100 (1954)

[c5] J. Steinberger and A. S. Bishop, Phys. Rev. 86, 171 (1952)

[c6] White, Jacobson, and Schulz, Phys. Rev. 88, 836 (1952)

[c7] Jarmie, Repp, and White, Phys. Rev. 91, 1023 (1953)

[c8] Jenkins, Luckey, Palfrey, and Wilson, Phys. Rev. 95, 179 (1954)

[c9] G. Bernardini and E. L. Goldwasser, Phys. Rev. 94, 729 (1954) 95, 857 (1954)

[c10] Vincent Peterson and I. George Henry, Phys. Rev. 96, 850 (1954)

[c11] Goldschmidt-Clermont, Osborn, and Winston, Phys. Rev. 91, 468 (1953)

[c12] G. S. Janes and W. L. Kraushaar, Phys. Rev. 93, 900 (1954)

[c13] K. Brueckner, Phys. Rev. 86, 106 (1952)

[c14] Walker, Oakley, and Tollestrup, Phys. Rev. 89, 1301 (1953)

[c15] K. Brueckner and K. M. Watson, Phys. Rev. 86, 923 (1952)

[c16] Omitted endnote

[c17] Walker, Teasdale, and Peterson, Phys. Rev. 92, 1090(A) (1953)

[c18] E. Segrè, K. T. BainbridgeExperimental Nuclear Physics (John Wiley and Sons, Inc., New York, 1953), Chapter by , pp. 576 ff

[c19] I. A. D. Lewis and B. Collinge, Rev. Sci. Instr. 24, 1113 (1953)

[c20] Raphael Littauer, Rev. Sci. Instr. 25, 148 (1954)

[c21] Blocker, Kenney, and Panofsky, Phys. Rev. 79, 419 (1950)

[c22] D. H. Cooper, thesis, California Institute of Technology, 1954 (unpublished)

[c23] Omitted endnote

[c24] Jacobson, Schulz, and Steinberger, Phys. Rev. 81, 894 (1951)

[c25] C. E. Wiegand, Phys. Rev. 83, 1085 (1951)

[c26] Durbin, Loar, and Havens, Phys. Rev. 88, 179 (1952)

[c27] Omitted endnote

[c28] Tollestrup, Keck, and Worlock, following paper [Phys. Rev. 99, 220 (1955)]

[c29] B. T. Feld, Phys. Rev. 89, 330 (1953)

[c30] M. Ross, Phys. Rev. 94, 454 (1954)

[c31] Geoffrey F. Chew, Phys. Rev. 95, 1669 (1954)

[c32] K. M. Watson, Phys. Rev. 95, 228 (1954)

[c33] M. Gell-Mann and K. M. Watson, Ann. Rev. Nuc. Sci. 4, 219 (1954)

[c34] K. M. Watson, Lectures at California Institute of Technology during the summer, 1954 (unpublished)

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Photoproduction of Positive Pions in Hydrogen-Magnetic Spectrometer Method

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