Learned, J.G.
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Elastic photoproduction of J/psi and Upsilon mesons at HERA.

The H1 collaboration Adloff, C. ; Andreev, V. ; Andrieu, B. ; et al.
Phys.Lett.B 483 (2000) 23-35, 2000.
Inspire Record 525022 DOI 10.17182/hepdata.46894

Cross sections for elastic photoproduction of J/Psi and Upsilon mesons are presented. For J/Psi mesons the dependence on the photon-proton centre-of-mass energy W_gammap is analysed in an extended range with respect to previous measurements of 26<=W_gammap<= 285 GeV. The measured energy dependence is parameterized as sigma_gammap proportional W_gammap^delta with delta=0.83+-0.07. The differential cross section dsigma/dt for J/Psi mesons is derived, its dependence on W_gammap and on t is analysed and the effective trajectory (in terms of Regge theory) is determined to be alpha(t)=(1.27+-0.05)+(0.08+-0.17)*t/GeV^2. Models based on perturbative QCD and on pomeron exchange are compared to the data.

5 data tables
Table 1

The cross sections for the elastic photoproduction of J/PSI particles.

Table 2

Differential cross section, DSIG/DT, for the elastic photoproduction of J/PSI particles.

Table 3

The slope of the DSIG/DT distribution.

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Elastic and inelastic photoproduction of J / psi mesons at HERA

The H1 collaboration Aid, S. ; Andreev, V. ; Andrieu, B. ; et al.
Nucl.Phys.B 472 (1996) 3-31, 1996.
Inspire Record 416868 DOI 10.17182/hepdata.44896

Results on \jpsi\ production in $e p$ interactionsin the H1 experiment at HERA are presented. The \jpsi\ mesons are produced by almost real photons ($Q~2\approx 0$) and detected via their leptonic decays. The data have been taken in 1994 and correspond to an integrated luminosity of $2.7\,\mbox{pb}~{-1}$. The $\gamma p$ cross section for elastic \jpsi\ production is observed to increase strongly with the \cm\ energy. The cross section for diffractive $J/\psi$ production with proton dissociation is found to be of similar magnitude as the elastic cross section. Distributions of transverse momentum and decay angle are studied and found to be in accord with a diffractive production mechanism. For inelastic \jpsi\ production the total $\gamma p$ cross section, the distribution of transverse momenta, and the elasticity of the \jpsi\ are compared to NLO QCD calculations in a colour singlet model and agreement is found. Diffractive \psiprime\ production has been observed and a first estimate of the ratio to \jpsi\ production in the HERA energy regime is given.

14 data tables
Table 1

J/PSI reconstructed via MU+ MU- decay mode.

Table 2

J/PSI reconstructed via E+ E- decay mode.

Table 3

J/PSI reconstructed via MU+ MU- decay mode.

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Photoproduction of the psi Particles

Camerini, U. ; Learned, J.G. ; Prepost, R. ; et al.
Phys.Rev.Lett. 35 (1975) 483, 1975.
Inspire Record 100670 DOI 10.17182/hepdata.21149

The s and t dependence of incoherent ψ(3100) photoproduction from deuterium has been measured at the Stanford Linear Accelerator Center. ψ(3700) photoproduction and ψ(3100) photoproduction from hydrogen have also been measured.

3 data tables
Table 1

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Table 2

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Table 3

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