Differential cross sections and spin density matrix elements for the reaction $\gamma p \to p \omega$

The CLAS collaboration Williams, M. ; Applegate, D. ; Bellis, M. ; et al.
Phys.Rev.C 80 (2009) 065208, 2009.
Inspire Record 829180 DOI 10.17182/hepdata.52667

High-statistics differential cross sections and spin density matrix elements for the reaction $\gamma p \to p \omega$ have been measured using the CLAS at Jefferson Lab for center-of-mass (CM) energies from threshold up to 2.84 GeV. Results are reported in 112 10-MeV wide CM energy bins, each subdivided into $\cos{\theta_{CM}^{\omega}}$ bins of width 0.1. These are the most precise and extensive $\omega$ photoproduction measurements to date. A number of prominent structures are clearly present in the data. Many of these have not previously been observed due to limited statistics in earlier measurements.

221 data tables

Differential cross section for the W range 1.72 to 1.73 GeV.

Differential cross section for the W range 1.73 to 1.74 GeV.

Differential cross section for the W range 1.74 to 1.75 GeV.

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Vector Meson Production by Polarized Photons at 2.8-GeV, 4.7-GeV, and 9.3-GeV

Ballam, Joseph ; Chadwick, G.B. ; Eisenberg, Y. ; et al.
Phys.Rev.D 7 (1973) 3150, 1973.
Inspire Record 73602 DOI 10.17182/hepdata.43496

We present results on vector-meson photoproduction via γp→Vp in the LBL-SLAC 82-in. hydrogen bubble chamber exposed to a linearly polarized photon beam at 2.8, 4.7, and 9.3 GeV. We find ρ0 production to have the characteristics of a diffractive process, i.e., a cross section decreasing slowly with energy and a differential cross section with slope of ∼ 6.5 GeV−2. Within errors the ρ0 production amplitudes are entirely due to natural-parity exchange. s-channel helicity is conserved to a high degree in the γ→ρ0 transition. We find evidence for small helicity-flip amplitudes for ππ pairs in the ρ0 region. Photoproduction of ω mesons is separated into its natural- (σN) and unnatural- (σU) parity-exchange contributions. The Eγ and t dependence and the spin density matrix of the unnatural-parity-exchange contribution are consistent with a one-pion-exchange process. The natural-parity-exchange part has characteristics similar to ρ0 production. At 9.3 GeV the ratio of σ(ρ0) to σN(ω) is ∼ 7. The slope of the φ differential cross section is ∼ 4.5 GeV−2, smaller than that of ρ0 and ω production. Natural-parity exchange is the main contributor to φ production. No evidence for higher-mass vector mesons is found in ππ, πππ, or KK¯ final states. The s and t dependences of Compton scattering as calculated from ρ, ω, and φ photoproduction using vector-meson dominance agree with experiment, but the predicted Compton cross section is too small by a factor of 2.

47 data tables

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A STUDY OF THE REACTIONS GAMMA P ---> OMEGA P AND GAMMA P ---> OMEGA DELTA+

The LAMP2 Group collaboration Barber, D.P. ; Dainton, J.B. ; Lee, L.C.Y. ; et al.
Z.Phys.C 26 (1984) 343-351, 1984.
Inspire Record 215619 DOI 10.17182/hepdata.16143

The differential and total corss sections and the decay density matrix elements have been measured for the reactions, γp→ωp and γp→ωΔ+ (1232) in the photon energy range 2.8 to 4.8 GeV. The total cross sections for ωΔ+ (1232) photo-production are found to be slightly larger than those for elastic ω photo-production in this energy range. The data are compared to the predictions of a theoretical model and the contributing exchange mechanics are discussed.

14 data tables

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Measurement of the Photoproduction Phases of the rho, omega, and phi Mesons

Bartalucci, S. ; Bertolucci, S. ; Bienlein, J.K. ; et al.
Nuovo Cim.A 44 (1978) 587, 1978.
Inspire Record 120711 DOI 10.17182/hepdata.37585

We measured 30 000 wide-angle electron-positron pairs from the reaction γ+p→p+e++e− in the invariant-mass region 500≤m≤1060 MeV. The photoproduction amplitudes of the ρ, ω and ϕ mesons were measured to deviate from being pure imaginary by 37.5°−3.1°+2.8°, 29.6°−12.9°+15.5°, 3.4°−4.2°+5.3°,respectively.

1 data table

DEVIATION OF VECTOR MESON PHOTOPRODUCTION PHASES FROM PURE IMAGINARY.


Study of photoproduction on hydrogen in a streamer chamber with tagged photons for 1.6 GeV $ < E_\gamma <$ 6.3 GeV Topological and reaction cross sections

The Aachen-Hamburg-Heidelberg-Munich collaboration Struczinski, W. ; Dittmann, P. ; Eckardt, V. ; et al.
Nucl.Phys.B 108 (1976) 45-74, 1976.
Inspire Record 100089 DOI 10.17182/hepdata.35779

We have studied photoproduction using a 1 m streamer chamber at DESY and a tagged photon beam with an energy range of 1.6 GeV < E γ < 6.3 GeV. We analysed approximately 30 000 events and report topological, channel and resonance production cross sections for a large number of reactions with three and five outgoing charged particles.

29 data tables

CHANNEL CROSS SECTIONS FOR 3, 5 AND 7 PRONG REACTIONS.

'PARAMETRIZATION'.

'INTERFERENCE'.

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