Holt, J.R.
GAMMA P --> ETA P
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Measurement of the beam asymmetry $\Sigma$ for $\pi^0$ and $\eta$ photoproduction on the proton at $E_\gamma = 9$ GeV

The GlueX collaboration Al Ghoul, H. ; Anassontzis, E.G. ; Austregesilo, A. ; et al.
Phys.Rev.C 95 (2017) 042201, 2017.
Inspire Record 1511149 DOI 10.17182/hepdata.76745

We report measurements of the photon beam asymmetry $\Sigma$ for the reactions $\vec{\gamma}p\to p\pi^0$ and $\vec{\gamma}p\to p\eta $ from the GlueX experiment using a 9 GeV linearly-polarized, tagged photon beam incident on a liquid hydrogen target in Jefferson Lab's Hall D. The asymmetries, measured as a function of the proton momentum transfer, possess greater precision than previous $\pi^0$ measurements and are the first $\eta$ measurements in this energy regime. The results are compared with theoretical predictions based on $t$-channel, quasi-particle exchange and constrain the axial-vector component of the neutral meson production mechanism in these models.

2 data tables
Table 1

Measurement of the beam asymmetry $\Sigma$ for $\pi^0$ photoproduction on the proton at $E_\gamma = 9$ GeV. The uncorrelated systematic errors (syst) are given in the table below along with a correlated normalization uncertainty (norm) of 3.6% due to the beam polarization.

Table 2

Measurement of the beam asymmetry $\Sigma$ for $\eta$ photoproduction on the proton at $E_\gamma = 9$ GeV. The uncorrelated systematic errors (syst) are given in the table below along with a correlated normalization uncertainty (norm) of 3.6% due to the beam polarization.


Eta photoproduction on the proton for photon energies from 0.75-GeV to 1.95-GeV

The CLAS collaboration Dugger, M. ; Ritchie, B.G. ; Ball, J. ; et al.
Phys.Rev.Lett. 89 (2002) 222002, 2002.
Inspire Record 603904 DOI 10.17182/hepdata.19406

Differential cross sections for γp→ηp have been measured with tagged real photons for incident photon energies from 0.75 to 1.95 GeV. Mesons were identified by missing mass reconstruction using kinematical information for protons scattered in the production process. The data provide the first extensive angular distribution measurements for the process above W=1.75  GeV. Comparison with preliminary results from a constituent quark model support the suggestion that a third S11 resonance with mass ∼1.8  GeV couples to the ηN channel.

6 data tables
Table 1

Cross sections for photon energies 0.775 to 0.925 GeV.

Table 2

Cross sections for photon energies 0.975 to 1.125 GeV.

Table 3

Cross sections for photon energies 1.175 to 1.325 GeV.

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Differential cross sections for the reactions gamma p-> p eta and gamma p -> p eta-prime

The CLAS collaboration Williams, M. ; Krahn, Z. ; Applegate, D. ; et al.
Phys.Rev.C 80 (2009) 045213, 2009.
Inspire Record 830257 DOI 10.17182/hepdata.52983

High-statistics differential cross sections for the reactions gamma p -> p eta and gamma p -> p eta-prime have been measured using the CLAS at Jefferson Lab for center-of-mass energies from near threshold up to 2.84 GeV. The eta-prime results are the most precise to date and provide the largest energy and angular coverage. The eta measurements extend the energy range of the world's large-angle results by approximately 300 MeV. These new data, in particular the eta-prime measurements, are likely to help constrain the analyses being performed to search for new baryon resonance states.

104 data tables
Table 1

Differential cross section for the W range 1.68 to 1.69 GeV.

Table 2

Differential cross section for the W range 1.69 to 1.70 GeV.

Table 3

Differential cross section for the W range 1.70 to 1.71 GeV.

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The Polarized Target Asymmetry in Photoproduction of $\Eta$ Mesons From Protons at 4-{GeV}

Bussey, P.J. ; Raine, C. ; Rutherglen, J.G. ; et al.
Nucl.Phys.B 185 (1981) 269-273, 1981.
Inspire Record 155784 DOI 10.17182/hepdata.34276

Measurements have been made of the polarised target asymmetry parameter T for eta photoproduction from protons at a photon energy of 4 GeV and t -values of −0.4, −0.6 and −0.8 (GeV/ c ) 2 . The results are compared with predictions for this quantity.

1 data table
Table 1

No description provided.


The photoproduction of eta mesons at small angles

Booth, P.S.L. ; Barton, J.S. ; Carroll, L.J. ; et al.
Nucl.Phys.B 25 (1971) 510-518, 1971.
Inspire Record 68819 DOI 10.17182/hepdata.33806

None

4 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Differential cross-sections for the photoproduction of eta mesons from protons near 2 gev

Booth, P.S.L. ; Carroll, L.J. ; Holt, J.R. ; et al.
Nucl.Phys.B 71 (1974) 211-216, 1974.
Inspire Record 94714 DOI 10.17182/hepdata.32321

Differential cross sections for the process γ p → p η have been measuredd at c.m. angles of 28°, 35° and 42° at incident energies between 2 GeV and 2.8 GeV. Data from an earlier experiment below 2 GeV have been re-analysed and corrected. The whole set of data is compared with the form ( s − M 2 ) 2 d σ /d t , which fits data at higher energies. There is good agreement above 2 GeV, particularly at the largest angle, but strong departures below.

2 data tables
Table 1

No description provided.

Table 2

THESE DATA ARE A REANALYSIS OF THOSE REPORTED IN P. S. L. BOOTH ET AL., NP B25, 510 (1971). THE CORRECTED RESULTS ARE IN GENERAL ABOUT TWICE THE OLD VALUES.


The Polarized Beam Asymmetry in Photoproduction of eta Mesons from Protons at 2.5-GeV and 3.0-GeV

Bussey, P.J. ; Raine, C. ; Rutherglen, J.G. ; et al.
Phys.Lett.B 61 (1976) 479-482, 1976.
Inspire Record 108515 DOI 10.17182/hepdata.27687

Measurements of the polarised beam asymmetry parameter Σ for eta photoproduction from protons, have been carried out at incident energies of 2.5 GeV and 3.0 GeV, and for various t -values between −0.2 (GeV/c) 2 and −1.2 (GeV/c) 2 . The values of Σ are close to +1 for values of | t | less than 0.7 (GeV/c) 2 , showing that there can be little contribution from unnatural parity exchange in any Regge exchange model of the process, in disagreement with present theories. Differential cross sections for the process werre also measured, and are consistent with those from other experiments.

2 data tables
Table 1

No description provided.

Table 2

No description provided.


The photoproduction of eta-mesons between 950 mev and 2.2 gev

Booth, P.S.L. ; Butler, M.F. ; Carroll, L.J. ; et al.
Lett.Nuovo Cim. 2S1 (1969) 66-70, 1969.
Inspire Record 58277 DOI 10.17182/hepdata.37407

None

1 data table
Table 1

No description provided.