GAMMA P --> PI0 P
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Angular dependence of the recoil proton polarization from the reaction $\gamma p \to \pi^0 p$ for photon energies between 360-MeV and 1200-MeV

Blum, P. ; Brinckmann, P. ; Brockmann, R. ; et al.
BONN-PI-1-105, 1970.
Inspire Record 1085812 DOI 10.17182/hepdata.70500

None

6 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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The Photoproduction of Neutral Pions from Protons Between 0.7-GeV and 1.7-GeV

Barton, J.S. ; Booth, P.S.L. ; Carroll, L.J. ; et al.
Nucl.Phys.B 84 (1975) 449-466, 1975.
Inspire Record 90496 DOI 10.17182/hepdata.32128

Measurements of differential cross sections for pi-zero photoproduction from protons have been made at angles between 60° and 140° c.m. in the photon energy range 0.7 GeV to 1.7 GeV. The data are compared with the rits provided by three recent partial-wave analyses of pion photoproduction and some significant discrepancies observed.

9 data tables
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The Photoproduction of Neutral Pions from Protons at Forward Angles in the Resonance Region

Booth, P.S.L. ; Carroll, L.J. ; Holt, J.R. ; et al.
Nucl.Phys.B 84 (1975) 437-448, 1975.
Inspire Record 90412 DOI 10.17182/hepdata.32127

Differential cross sections for the photoproduction of pi-zero mesons from protons have been measured at angles between 10° and 70° c.m. in the energy range 0.85 GeV to 1.30 GeV. The values are compared with the fits to pion photoproduction data from three recent partial-wave analyses.

1 data table

Asymmetry of the cross section of the reaction $\gamma$P $\rightarrow$ P$\pi^{0}$ in the energy interval 0.9-1.65 GeV at $\theta _{\pi}^{0 cms}$ = 110°

Abramyan, L.O. ; Avakyan, R.O. ; Akopov, N.Z. ; et al.
JETP Lett. 23 (1976) 375-378, 1976.
Inspire Record 1393126 DOI 10.17182/hepdata.39803

None

2 data tables
Table 1

THE ERRORS INCLUDE THE 10 PCT ERROR IN THE EFFECTIVE PHOTON POLARIZATION.

Table 2

No description provided.


Photoproduction of $\pi^\circ$'S from protons in the forward direction in the region of the second and third resonances

Talman, Richard Michael ; Tollestrup, Alvin V. ;
CIT-8, 1963.
Inspire Record 44255 DOI 10.17182/hepdata.37170

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The cross section for photoproduction of neutral pions from protons has been measured at energies near 750, 915 and 1150 Mev and over most of the forward-going [...] C.M. hemisphere. The experimental technique consisted of detecting both of the [...] decay photons with lead glass total absorption counters and, when convenient, the recoil proton with a single scintillation counter. The method is subject to rather large systematic errors but, within these, our results are consistent with other experiments wherever there are overlapping points. Our data has the striking feature that the cross section is very small at [...] in the region of the second and third pion nucleon resonances. Also, although the data is not inconsistent with a simple first, second and third resonance model, it appears likely that above the third resonance the pole process consisting of the exchange of a single vector meson is becoming important or even dominant. The evidence at this time mildly suggests that this behaviour is largely due to [...] mesons and under that hypothesis we are able to estimate some [...] meson coupling constants. For example, using a prescription of Gell-Mann and Zachariasen, we estimate the partial width for the decay [...] to be 240 Kev.

1 data table
Table 1

No description provided.


Linearly polarised photon beams at ELSA and measurement of the beam asymmetry in pi^0-photoproduction off the proton

The CBELSA & TAPS collaborations Elsner, D. ; Bantes, B. ; Bartholomy, O. ; et al.
Eur.Phys.J.A 39 (2009) 373-381, 2009.
Inspire Record 799078 DOI 10.17182/hepdata.50479

At the electron accelerator ELSA a linearly polarised tagged photon beam is produced by coherent bremsstrahlung off a diamond crystal. Orientation and energy range of the linear polarisation can be deliberately chosen by accurate positioning of the crystal with a goniometer. The degree of polarisation is determined by the form of the scattered electron spectrum. Good agreement between experiment and expectations on basis of the experimental conditions is obtained. Polarisation degrees of P = 40% are typically achieved at half of the primary electron energy. The determination of P is confirmed by measuring the beam asymmetry, \Sigma, in pi^0 photoproduction and a comparison of the results to independent measurements using laser backscattering.

20 data tables
Table 1

Beam asymmetry as a function of the PI0 centre of mass scattering angle.

Table 2

Beam asymmetry as a function of the PI0 centre of mass scattering angle.

Table 3

Beam asymmetry as a function of the PI0 centre of mass scattering angle.

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Neutral pion photoproduction off protons in the energy range 0.3-GeV < E(gamma) < 3-GeV.

The CB-ELSA collaboration Bartholomy, O. ; Crede, V. ; van Pee, H. ; et al.
Phys.Rev.Lett. 94 (2005) 012003, 2005.
Inspire Record 654179 DOI 10.17182/hepdata.41902

Single pi0 photoproduction has been studied with the CB-ELSA experiment at Bonn using tagged photon energies between 0.3 and 3.0 GeV. The experimental setup covers a very large solid angle of about 98% of 4 pi. Differential cross sections (d sigma)/(d Omega) have been measured. Complicated structures in the angular distributions indicate a variety of different resonances being produced in the s channel intermediate state gamma p --> N* (Delta*) --> p pi0. A combined analysis including the data presented in this letter along with other data sets reveals contributions from known resonances and evidence for a new resonance N(2070)D15.

14 data tables
Table 1

Total cross section for GAMMA P --> P PI0 obtained by integration of the angular distributions and extrapolation into the forward and backward regions using the PWA result.

Table 2

Differential cross section as a function of c.m. angle for the photon energy range 300 to 425 GeV.

Table 3

Differential cross section as a function of c.m. angle for the photon energy range 425 to 550 GeV.

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Measurement of Asymmetry in Photoproduction of pi0 Meson in the Resonance Region

Avakian, R.O. ; Avakian, E.O. ; Avetisian, A.E. ; et al.
Yad.Fiz. 26 (1977) 1014-1017, 1977.
Inspire Record 126317 DOI 10.17182/hepdata.19036

None

1 data table
Table 1

Axis error includes +- 10/10 contribution.


Photoproduction of Neutral Pions at Backward Angles in the Resonance Region and the $\eta$ - Cusp

Althoff, K.H. ; Gies, M. ; Kaul, O. ; et al.
Z.Phys.C 1 (1979) 327, 1979.
Inspire Record 140694 DOI 10.17182/hepdata.50217

At the Bonn 2.5 GeV electron synchrotron we have measured the differential cross section of the reaction γp→π0p at a pion CM angle of 170° and at photon energiesKγ between 0.6 and 1.8 GeV. In comparison to previous measurements the accuracy of the data was improved substantially. For the first time in neutral pion photoproduction a cusp structure at the η-threshold has been confirmed [1].

1 data table
Table 1

No description provided.


RECOIL PROTON POLARIZATION IN pi0 PHOTOPRODUCTION

Bloom, Elliott D. ; Heusch, C.A. ; Prescott, C.Y. ; et al.
Phys.Rev.Lett. 19 (1967) 671, 1967.
Inspire Record 51327 DOI 10.17182/hepdata.21757

None

1 data table
Table 1

No description provided.


Pi+- and pi0 production by polarized photons in the resonance region

Alspector, J. ; Fox, D. ; Luckey, David ; et al.
Phys.Rev.Lett. 28 (1972) 1403-1406, 1972.
Inspire Record 75484 DOI 10.17182/hepdata.21872

We have measured the cross sections at 90° c.m. for π± and π0 photoproduction with polarized photons. The photon energies ranged from 0.8 to 2.2 GeV. We compare the resonant "bumps" in the cross section with theoretical models. The measured asymmetry agrees with a quark-model calculation though the predicted cross sections are low.

5 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Recoil-proton polarization in neutral-pion photoproduction between 1000 and 1800 mev

Tanaka, N. ; Castro, M.M. ; Milburn, Richard H. ; et al.
Phys.Rev.D 8 (1973) 1-8, 1973.
Inspire Record 81985 DOI 10.17182/hepdata.22112

Measurements are presented of the recoil-proton polarization for π0 photoproduction angles near 64° in the c.m. system. The steep angular dependence observed by others at lower energies persists to at least 1500 MeV, and the polarization crosses through zero near 63° over the entire 900-1600-MeV energy interval. Summary fits are made to available recoil-proton polarization data, 950-1250 MeV, and are found to require terms of order cos3θ, but no higher.

1 data table
Table 1

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


Photoproduction of neutral pions off hydrogen at photon energies between 0.55 and 2.2 gev at a cm-angle of 120 degrees

Feller, P. ; Herr, H. ; Hilger, E. ; et al.
Phys.Lett.B 49 (1974) 197-200, 1974.
Inspire Record 95299 DOI 10.17182/hepdata.27964

The differential cross section has been measured for the reaction γ +p→ π o + p at the Bonn 2.5 GeV electron synchrotron in the energy range from 0.55 to 2.2 GeV at a c.m.angle of 120 degrees.

1 data table
Table 1

No description provided.


Pi0 and pi+ Production with Polarized Photons in the Energy Range 1-GeV - 2-GeV

Abrahamian, L.O. ; Avakian, R.O. ; Aganyants, Aleksandr O. ; et al.
Phys.Lett.B 48 (1974) 463-466, 1974.
Inspire Record 90760 DOI 10.17182/hepdata.43798

The asymmetry of π o and π + photoproduction from hydrogen has been measured. The π o -mesons were detected at 130° cms with E γ ranged from 0.9 to 1.65 GeV, and the π + -mesons at 40° cms with E γ ranged from 0.9 to 1.2 GeV. The results agree with model predictions of single pion photoproduction in the resonance region using fixed- t dispersion relations.

7 data tables
Table 1

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

Table 2

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

Table 3

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

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Polarization of secondary protons from the gamma + p ---> pi0 + p reaction in the third resonance region

Derebchinskii, A.I. ; Tonapetyan, S.G. ; Konovalov, O.G. ; et al.
Zh.Eksp.Teor.Fiz. 66 (1974) 68-73, 1974.
Inspire Record 96653 DOI 10.17182/hepdata.39968

None

1 data table
Table 1

No description provided.


Backward photoproduction of neutral pions off hydrogen at photon energies between 0.4 and 2.2 gev

Becks, H. ; Feller, P. ; Menze, D. ; et al.
Nucl.Phys.B 60 (1973) 267-276, 1973.
Inspire Record 83927 DOI 10.17182/hepdata.6749

The differential cross section has been measured for the reaction γ +p→p+ π o at the Bonn 2.5 GeV electron synchrotron in the energy range from 0.4 to 2.2 GeV for a c.m. angle of 150 degrees. The protons were detected in a magnetic spectrometer system. The excitation curve shows a distinct resonance structure. The total corrections to the counting rate are about 3%. The contribution of the process γ +p→p+2 π was separated. The uncertainty of this separation leads to an error of about 4% in the cross section.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


Angular Dependence of the Polarization of the Recoil Proton from the Reaction gamma p --> pi0 p in the Region of the Second Resonance

Blum, P. ; Brinckmann, P. ; Brockmann, R. ; et al.
Z.Phys.A 277 (1976) 311, 1976.
Inspire Record 108242 DOI 10.17182/hepdata.16619

The polarization of the recoil proton from the reactionγp→π0p has been measured for photon energies between 600 and 1,200 MeV and pion c.m. angles between 90° and 150°.

1 data table
Table 1

No description provided.


Angular Dependence of the Polarization of the Recoil Proton from the Reaction gamma p --> pi0 p in the Region of the Third Resonance

Blum, P. ; Brockmann, R. ; Mohr, W. ;
Z.Phys.A 278 (1976) 275, 1976.
Inspire Record 108304 DOI 10.17182/hepdata.16615

The polarization of the recoil proton from the reactionγp→π0p has been measured for photon energies between 900–1,350 MeV and pion c.m. angles between 70° and 150°. There are significant deviations from recent analysis.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


Forward Photoproduction of Neutral Pions on Protons in the Third Resonance Region

Husmann, D. ; Jansen, W. ; Lohr, B. ; et al.
Nucl.Phys.B 126 (1977) 436-442, 1977.
Inspire Record 119605 DOI 10.17182/hepdata.35324

Four angular distributions of the differential cross section of the reaction γ + p → π 0 + p have been measured at the Bonn 2.5 GeV Synchrotron at pion c.m. angles between 3° and 63° in the photon energy range from 0.9 GeV to 1.2 GeV. The π 0 mesons were detected by their two decay photons. The data are compared with data of other laboratories and predictions of two recent partial-wave analyses.

4 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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The Polarized Target Asymmetry for Neutral Pion Photoproduction from Protons in the Photon Energy Range 0.7-GeV-1.45-GeV

Booth, P.S.L. ; Carroll, L.J. ; Court, G.R. ; et al.
Nucl.Phys.B 121 (1977) 45-57, 1977.
Inspire Record 111591 DOI 10.17182/hepdata.35454

Measurements have been made of the target asymmetry parameter for photoproduction of π 0 mesons from protons, using a butanol polarised target with a 3 He cryostat. Results were obtained at 14 incident photon energies between 0.7 GeV and 1.45 GeV over an angular range ∼40° to 145° c.m. The recent analysis of Barbour and Crawford provides a very good fit to the data.

14 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Photoproduction of pi0 Mesons from Hydrogen at 180-degrees

Cassiday, G.L. ; Fischer, H. ; Ito, A. ; et al.
Phys.Rev.Lett. 21 (1968) 933-934, 1968.
Inspire Record 944912 DOI 10.17182/hepdata.21702

We measured the π0 photoproduction differential cross section at 180° for a range of incident photon energies between 650 and 1750 MeV. The cross sections are dominated by the D13(1525), D15(1688), and F37(1920) resonances.

1 data table
Table 1

No description provided.


Photoproduction of $\pi^0$ in the Backward Direction

Buschhorn, G. ; Heide, P. ; Kotz, U. ; et al.
Phys.Rev.Lett. 20 (1968) 230-232, 1968.
Inspire Record 54459 DOI 10.17182/hepdata.21735

None

1 data table
Table 1

No description provided.


Photoproduction of pi0 from Hydrogen near the Second and Third Pion-Nucleon Resonances

Ward, C. ; Kenton, B. ; York, C. ;
Phys.Rev. 159 (1967) 1176-1186, 1967.
Inspire Record 944950 DOI 10.17182/hepdata.26564

Measurements of the differential cross section for the process γ+p→π0+p have been made at eight pion center-of-mass angles in the range 51-135° and for incident photon energies from approximately 600-1200 MeV. The bremsstrahlung photon beam used was obtained from the California Institute of Technology electron synchrotron. Both the recoil proton and one γ ray from the decay of the π0 were detected. The incident photon energy was determined by measuring the laboratory angle and time of flight of the recoil proton. The angular distributions obtained indicate that the third pion-nucleon resonance is predominantly a D(52) resonance excited by a magnetic quadrupole transition. It can also be concluded that any contribution to the π0 photoproduction cross section from a virtual vector-meson exchange process is probably negligible in the region of the second and third pion-nucleon resonances.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


Photoproduction of Single Neutral Pions from Hydrogen at Energies 0.6 to 1.2 BeV

Diebold, R. ;
Phys.Rev. 130 (1963) 2089-2097, 1963.
Inspire Record 944976 DOI 10.17182/hepdata.26774

Measurements of the differential cross section for the process γ+p→π0+p have been made at three pion center-of-mass angles: 60°, 90°, and 120°. Values were obtained at intervals of 0.05 BeV (incident laboratory photon energy, k) from approximately 0.6 to 1.2 BeV. Most of the data were obtained by detecting only the recoil protons with a large, wedge-shaped, single-focusing magnetic spectrometer and associated equipment. For θ′π0=60° and k≤0.94 BeV the π0 decays were also required, the decay photons being detected by a lead glass total absorption counter. Although the experimental resolution was considerably narrower than that of most of the previous experiments, its averaging effect was still appreciable in certain regions. Using a six-parameter fit, the data at each angle were unfolded in an effort to eliminate the effects of resolution and to obtain the true cross sections as a function of energy. The results compare reasonably well with those of previous experiments once differences in resolutions and systematic errors are taken into account. The results did not agree with the predictions of a simple resonance model with the resonance quantum numbers suggested by Peierls. The positions and widths of the two cross-section peaks in this energy region are quite similar to those observed in π−p scattering.

1 data table
Table 1

No description provided.


Pi0 and pi+ Production with Polarized Photons in the Resonance Region

Abrahamian, L.O. ; Avakian, R.O. ; Aganyants, Aleksandr O. ; et al.
EFI-136-75-YEREVAN, 1975.
Inspire Record 100164 DOI 10.17182/hepdata.43767

None

2 data tables
Table 1

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

Table 2

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


Differential cross-section measurements for pi0 photoproduction in the region of the third nucleon resonance

Booth, P.S.L. ; Butler, M.F. ; Carroll, L.J. ; et al.
Nuovo Cim.A 13 (1973) 235-247, 1973.
Inspire Record 86978 DOI 10.17182/hepdata.37826

Differential cross-sections have been measured for π0 photoproduction over the energy range 0.8 GeV to 1.4 GeV and at angles between 50° and 90° c.m.

1 data table
Table 1

No description provided.