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Photoproduction of Positive Pions in Hydrogen-Magnetic Spectrometer Method

Walker, R.L. ; Teasdale, J.G. ; Peterson, V.Z. ; et al.

Phys.Rev. 99 (1955) 210-219, 1955.

Inspire Record 46872 DOI 10.17182/hepdata.26403

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+Bcosθ+Ccos2θ. 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 cm2, and falls off above the maximum faster than λ2.

10 data tables

Table 1

No description provided.

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Photoproduction of Neutral Pions from Hydrogen at Forward Angles from 240 to 480 Mev

McDonald, W.S. ; Peterson, V.Z. ; Corson, D.R. ;

Phys.Rev. 107 (1957) 577-585, 1957.

Inspire Record 48187 DOI 10.17182/hepdata.26895

Recoil protons from the process γ+p→p+π0 have been detected by nuclear emulsions placed within a hydrogen-gas target and used to measure the differential cross section for production of neutral pions. In this manner protons of energies as low as 5 Mev can be detected at laboratory angles corresponding to emission of a pion at center-of-momentum (c.m.) angles as low as 26°. This experiment thus supplements that of Oakley and Walker which is in the same range of photon energies (240-480 Mev), but is restricted to pion c.m. angles greater than about 70° owing to higher minimum detectable proton energy. Common experimental points provide intercomparison of absolute values. Angular distributions are analyzed in the form dσdΩ=A+Bcosθ+Ccos2θ in the c.m. system. The combined Oakley-Walker and present data give the average value of the ratio AC as -1.60±0.10 in the energy range from 260 to 450 Mev. The coefficient B, which gives the front-back asymmetry, passes through zero below the resonance energy of 320 Mev and is positive at higher energies. These results are consistent with magnetic dipole absorption leading to a state of the pion-nucleon system of angular momentum 32, together with a finite amount of S-wave interference.

1 data table

Table 1

Axis error includes +- 7.3/7.3 contribution.

Polarization of the Recoil Proton from pi0 Photoproduction in Hydrogen

Maloy, J.O. ; Peterson, V.Z. ; Salandin, G.A. ; et al.

Phys.Rev. 139 (1965) B733-B746, 1965.

Inspire Record 944960 DOI 10.17182/hepdata.26657

The polarization of the recoil proton in neutral single-pion photoproduction from hydrogen, γ+p→p+π0, has been measured for pion center-of-mass angles near 90° at 7 photon energies from 450 to 900 MeV. The polarization rises to a maximum of 0.58 near 600 MeV and is still 0.42 at 900 MeV. The sign of the polarization is negative in the sense of k×q, where k is the photon momentum and q is the pion momentum. The measured values are given as functions of laboratory photon energy and c.m. pion angle as follows: 450 MeV, 109°, -0.16±0.14; 525 MeV, 84°, -0.36±0.19; 585 MeV, 86°, -0.58±0.15; 660 MeV, 77°, -0.51±0.17; 755 MeV, 76°, -0.55±0.15; 810 MeV, 89°, -0.45±0.17; 895 MeV, 90°, -0.42±0.16. The recoil protons were momentum-analyzed with a magnetic spectrometer. Nuclear emulsion was used as scatterer and detector. The emulsion technique is discussed in detail. The number of individual scatterings in emulsion used for each measurement varied between 750 and 1000.

1 data table

Table 1

No description provided.

Pi- p interactions at 3.25 gev/c. two-prong events

Guzhavin, V.M. ; Vetlitskii, I.A. ; Kaidalov, A.B. ; et al.

Yad.Fiz. 14 (1971) 354-366, 1971.

Inspire Record 69448 DOI 10.17182/hepdata.19292

None

1 data table

Table 1

BREIT-WIGNER RESONANCE FITS WITH BACKGROUND.

Elastic backward scattering of negative pions on neutrons at 23 and 40 gev/c

Babaev, A. ; Brakhman, E. ; Eliseev, G. ; et al.

Phys.Lett.B 38 (1972) 342-344, 1972.

Inspire Record 75856 DOI 10.17182/hepdata.28343

The differential cross sections of the elastic backward scattering reaction π − n→n π − has been measured at 23 and 40 GeV/ c in the u -interval −0.07 ⩽ u ⩽ 0.01 (GeV/ c ) 2 .

2 data tables

Table 1

No description provided.

Table 2

No description provided.

Production of f0-meson in pi- p ---> p pi+ pi- pi- reaction at momentum 4.5 gev/c

Kliger, G.K. ; Kolganov, V.Z. ; Smolyankin, V.T. ; et al.

Yad.Fiz. 17 (1973) 555-560, 1973.

Inspire Record 85131 DOI 10.17182/hepdata.19270

None

1 data table

Table 1

No description provided.

TOTAL CROSS-SECTION MEASUREMENT OF NEUTRONS ON PROTONS AND NUCLEI OVER THE ENERGY RANGE 28-GeV - 54-GeV

Babaev, A. ; Brachman, E. ; Eliseev, G. ; et al.

Phys.Lett.B 51 (1974) 501-504, 1974.

Inspire Record 80943 DOI 10.17182/hepdata.27923

The results of the total cross section measurements of neutrons on protons, deuterons and nuclei C, O, Al, Cu, Sn, Pb in the energy range of 28–54 GeV are reported.

3 data tables

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