MEASUREMENT OF THE POLARIZED TARGET ASYMMETRY ON gamma p ---> pi+ n IN THE THIRD RESONANCE REGION

Fujii, K. ; Hayashii, H. ; Iwata, S. ; et al.
DPNU-28-81, 1981.
Inspire Record 166957 DOI 10.17182/hepdata.34173

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4 data tables

Axis error includes +- 3/3 contribution.

Axis error includes +- 3/3 contribution.

Axis error includes +- 3/3 contribution.

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POLARIZATION OF RECOIL NEUTRONS FROM SINGLE PION PHOTOPRODUCTION OFF PROTONS IN THE RESONANCE REGION

Egawa, K. ; Ishii, T. ; Daigo, M. ; et al.
Nucl.Phys.B 188 (1981) 11-28, 1981.
Inspire Record 171265 DOI 10.17182/hepdata.34257

The polarization of the recoil neutrons from the reaction γ p→ π + n was measured at a c.m. angle of 105° for incident photon energies between 675 and 1125 MeV. A scattered π + meson and a recoil neutron were detected in coincidence with a magnetic spectrometer and a neutron polarimeter system using liquid hydrogen. Results are compared with recent phenomenological analyses and the other existing data measured by the double polarization measurement technique.

1 data table

ERRORS ARE STATISTICAL ONLY.


A Study of Charged Pseudoscalar Meson Photoproduction From Hydrogen and Deuterium With 16-{GeV} Linearly Polarized Photons

Quinn, D.J. ; Rutherfoord, J.P. ; Shupe, M.A. ; et al.
Phys.Rev.D 20 (1979) 1553, 1979.
Inspire Record 140543 DOI 10.17182/hepdata.24208

The asymmetries in forward π−N, π−Δ, and K+−(Λ+Σ) photoproduction have been measured with a 16-GeV linearly polarized beam. The experimental method and the procedures for extracting cross sections and asymmetries from the data are discussed in detail. Information on the energy and momentum-transfer dependence of cross sections for natural- and unnatural-parity exchange, interference between exchanges of opposite G parity, and vector-meson dominance is obtained and discussed.

7 data tables

ASYMMETRIES AND DIFFERENTIAL CROSS SECTIONS FOR PION-NUCLEON PHOTOPRODUCTION WERE FIRST PUBLISHED IN D. J. SHERDEN ET AL., PRL 30, 1230 (1973) AND PRL 31, 667 (1973) (ERRATUM). THESE SLIGHTLY REVISED NUMBERS ARE INCLUDED IN THE RECORD OF THE 1973 PAPER.

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The Measurement of Polarized Target Asymmetry on gamma p --> pi+ n Below 1.02-GeV

Fukushima, M. ; Horikawa, N. ; Kajikawa, R. ; et al.
Nucl.Phys.B 130 (1977) 486-504, 1977.
Inspire Record 119547 DOI 10.17182/hepdata.35243

The polarized target asymmetry for the process γ p → π + n has been measured for incident photon energies below 1.02 GeV over a range of c.m. angles from 40° to 160°. π + mesons from a polarized butanol target were detected by a magnetic spectrometer. The results are compared with predictions given by existing analyses. A tentative interpretation of the data is performed, and a larger contribution of S-wave resonances is suggested. The photocouplings of dominant resonances were hardly changed by the inclusion of new data and they seem to be almost uniquely determined.

1 data table

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Photoproduction of pi+ Mesons on Polarized Protons

Genzel, H. ; Heide, P. ; Knutel, J. ; et al.
Nucl.Phys.B 92 (1975) 196-206, 1975.
Inspire Record 98235 DOI 10.17182/hepdata.32060

The asymmetry of the cross sections for the photoproduction of π + mesons on polarized protons γ + p↑ → π + + n has been studied in the four-momentum transfer range 0.1 ⩽ | t | ⩽ 1.25 (GeV/ c ) 2 for photon energies of 2.5, 3.4 and 5.0 GeV. The measurements were carried out on a polarized butanol target. Both particles in the final state were detected: the pion by a magnetic spectrometer, the recoil nucleon in a scintillation counter matrix. The asymmetry was found to be negative with values around −0.4.

3 data tables

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Polarized Target Asymmetry in $\pi^+$ Photoproduction Between 0.3-GeV and 1.0-GeV at 130°

Feller, P. ; Fukushima, M. ; Horikawa, N. ; et al.
Nucl.Phys.B 102 (1976) 207, 1976.
Inspire Record 90055 DOI 10.17182/hepdata.36079

The polarized target asymmetry for γ + p → π + + n was measured at c.m. angles around 130° for the energy range between 0.3 and 1.0 GeV. A magnetic spectrometer system was used to detect π + mesons from the polarized butanol target. The data show two prominent positive peaks at 0.4 and 0.8 GeV and a deep minimum at 0.6 GeV. These features are well reproduced by the phenomenological analysis made by us.

1 data table

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ASYMMETRIES IN CHARGED PION PHOTOPRODUCTION ON NUCLEONS BY 16-GeV POLARIZED PHOTONS

Sherden, D. ; Siemann, R. ; Sinclair, Charles K. ; et al.
Phys.Rev.Lett. 30 (1973) 1230, 1973.
Inspire Record 81026 DOI 10.17182/hepdata.21357

Asymmetries in charged-pion photoproduction from hydrogen and deuterium have been measured with 16-GeV linearly polarized photons. Considerable energy dependence is seen in the natural-parity contribution to the π−π+ ratio from deuterium, and in the unnatural-parity part of the cross section for γn→π−p. The energy dependence of this latter cross section is consistent with the expected from a conventional pion Regge trajectory.

5 data tables

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Measurement of the asymmetry for pi+ photoproduction from polarized protons between 300 and 900 mev

Arai, S. ; Fukui, S. ; Horikawa, N. ; et al.
Nucl.Phys.B 48 (1972) 397-414, 1972.
Inspire Record 84444 DOI 10.17182/hepdata.32778

The asymmetry of the cross section for π + photoproduction from a polarized butanol target has been measured at a c.m. angle 90° and photon energies between 300 and 900 MeV by a single-arm spectrometer detecting positive pions. Our results indicate that the asymmetry has clear positive peaks at photon energies 400 and 700 MeV with a deep valley at about 600 MeV. The general feature of the results is well reproduced by the phenomenological analyses made by Walker and ourselves; however, the best fit to the polarized target asymmetry data seems to give a somewhat different set of parameters from that given by Walker.

1 data table

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Small momentum transfer pi+ production with linearly polarized photons

Burfeindt, H. ; Buschhorn, G. ; Geweniger, C. ; et al.
Phys.Lett.B 33 (1970) 509-510, 1970.
Inspire Record 69381 DOI 10.17182/hepdata.28537

Previous measurements of the cross section asymmetry for single π + production on protons with linearly polarized photons of 3.4 GeV have been extended to momentum transfers within the forward peak, i.e. − = 0.0026, 0.006 and 0.01 (GeV/ c ) 2 . The results are in good agreement with pion exchange models.

1 data table

Axis error includes +- 6/6 contribution.


$\pi^+$ production with linearly polarized photons

Geweniger, C. ; Heide, P. ; Kötz, U. ; et al.
Phys.Lett.B 29 (1969) 41-44, 1969.
Inspire Record 56795 DOI 10.17182/hepdata.29060

Single π + production on protons by linearly polarized photons of 2.5 to 5 GeV was measured at squared four momentum transfers t between −0.01 and −0.6 (GeV/ c ) 2 . The results show that the differential cross section d σ ⊥ d t with the electric vector of the photon perpendicular to the reaction plane is much larger than d σ ‖ d t with the electric vector parallel to the reaction plane. The predictions of Regge models and of the vector meson dominance model are briefly discussed.

3 data tables

Axis error includes +- 0.0/0.0 contribution (?////).

Axis error includes +- 0.0/0.0 contribution (?////).

Axis error includes +- 0.0/0.0 contribution (?////).