Photoproduction of ϱ0 and ω on hydrogen at photon energies of 20 to 70 GeV

Aston, D.; Atkinson, M.; Bailey, R.; Ball, A. H.; Bautsch, H.J.; Bouquet, B.; Brookes, Graham; Bröring, J.; Bussey, P.; Clarke, D.; Clegg, A.B.; Dalmagne, B.; Rosny, G. De; Diekmann, B.; Donnachie, A.; Draper, Michael; Drévillon, B.; Duerdoth, I. P.; Dufey, J.P.; Ellison, R. J.; Ezra, D.; Feller, P.; Ferrer, A.; Flynn, Phil; Galbraith, W.; George, R.; Gill, S.; Goldberg, M.; Goodman, S.; Graves, W.; Grosstête, B.; Hampson, P.G.; Héinloth, K.; Hughes-Jones, R. E.; Hutton, J. S.; Ibbotson, M.; Jung, M.; Katsanevas, S.; Kemp, M.A.R.; Kovacs, F.; Kumar, B. R.; Lafferty, G.; Lane, J.B.; Lévy, J. M.; Liebenau, V.; Litt, J.; London, G.W.; Mercer, D.; Morris, J. V.; Müller, K.; Newton, D.; Paul, E.; Pétroff, P.; Pons, Y.; Raine, C.; Richard, F.; Richter, R.; Roberts, J.; Roudeau, P.; Rougé, A.; Rumpf, M.; Sené, M.; Six, J.; Skillicorn, I. O.; Sleeman, J. C.; Smith, K. M.; Steinhauer, C.; Storr, K.M.; Thompson, R. J.; Treille, D.; Vaissière, Ch De La; Videau, H.; Videau, I.; Waite, A. P.; Wijangco, A.; Wójcik, W.; Wuthrick, J.P.; Yiou, T. P.

doi:10.1016/0550-3213(82)90102-x

“…Figure 26 summarises α ′ measurements by H1 and ZEUS for DVCS and in photo-and electroproduction of ρ, φ and J/ψ mesons. The α ′ measurement for ρ photoproduction [20], which combines the ZEUS data at high energy with OMEGA results [134] at low energy, is α ′ = 0.12 ± 0.04 GeV tion and is similar, within errors, to values of α ′ in electroproduction. Measurements of α ′ at large |t| are consistent with 0, with small errors on the J/ψ measurements [13,30,31].…”

Section: Slope Of the Effective Pomeron Trajectorymentioning

confidence: 87%

Diffractive electroproduction of ρ and ϕ mesons at HERA

Aaron¹,

Martin²,

Alexa³

et al. 2010

J. High Energ. Phys.

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Diffractive electroproduction of ρ and φ mesons is measured at HERA with the H1 detector in the elastic and proton dissociative channels. The data correspond to an integrated luminosity of 51 pb −1 . About 10500 ρ and 2000 φ events are analysed in the kinematic range of squared photon virtuality 2.5 ≤ Q 2 ≤ 60 GeV 2 , photon-proton centre of mass energy 35 ≤ W ≤ 180 GeV and squared four-momentum transfer to the proton |t| ≤ 3 GeV 2 . The total, longitudinal and transverse cross sections are measured as a function of Q 2 , W and |t|. The measurements show a transition to a dominantly "hard" behaviour, typical of high gluon densities and small qq dipoles, for Q 2 larger than 10 to 20 GeV 2 . They support flavour independence of the diffractive exchange, expressed in terms of the scaling variable (Q 2 +M 2 V )/4, and proton vertex factorisation. The spin density matrix elements are measured as a function of kinematic variables. The ratio of the longitudinal to transverse cross sections, the ratio of the helicity amplitudes and their relative phases are extracted. Several of these measurements have not been performed before and bring new information on the dynamics of diffraction in a QCD framework. The measurements are discussed in the context of models using generalised parton distributions or universal dipole cross sections.

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“…If these NMC data are truly to be interpreted as a measurement of ρ-and φ-meson electroproduction on a nucleon then a comparison with recent data from HERA (at higher energy but similar q 2 ) would entail that, at large-q 2 , electroproduction cross sections exhibit The ρ-meson data (triangles) are from Refs. [35,36,[44][45][46][47]. The φ-meson data (squares) are from…”

Section: B Electroproduction Of φ Mesonsmentioning

confidence: 99%

Exclusive diffractive processes and the quark substructure of mesons

Pichowsky

¹

,

Lee

²

1997

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“…

Recent small-t ZEUS data for exclusive ρ photoproduction are in excellent agreement with exchange of the classical soft pomeron with slope α ′ = 0.25 GeV −2 . Adding in a flavour-blind hard-pomeron contribution, whose magnitude is calculated from the data for exclusive J/ψ photoproduction, gives a good fit also to the ZEUS data for ρ photoproduction at larger values of t, and to φ photoproduction.The ZEUS collaboration has recently suggested [1] that their data for exclusive ρ photoproduction at HERA, when combined with lower-energy data [2] lead to a slope α ′ for the trajectory of the soft pomeron that differs significantly from the classical value α ′ = 0.25 GeV −2 . A main message of this paper is to disagree with this conclusion; we show that in fact the classical value is confirmed by the data.

…”

mentioning

confidence: 99%

“…The ZEUS collaboration has recently suggested [1] that their data for exclusive ρ photoproduction at HERA, when combined with lower-energy data [2] lead to a slope α ′ for the trajectory of the soft pomeron that differs significantly from the classical value α ′ = 0.25 GeV −2 . A main message of this paper is to disagree with this conclusion; we show that in fact the classical value is confirmed by the data.…”

mentioning

confidence: 99%

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Exclusive vector photoproduction: confirmation of Regge theory

Donnachie

¹

,

Landshoff

²

2000

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Recent small-t ZEUS data for exclusive ρ photoproduction are in excellent agreement with exchange of the classical soft pomeron with slope α ′ = 0.25 GeV −2 . Adding in a flavour-blind hard-pomeron contribution, whose magnitude is calculated from the data for exclusive J/ψ photoproduction, gives a good fit also to the ZEUS data for ρ photoproduction at larger values of t, and to φ photoproduction.The ZEUS collaboration has recently suggested [1] that their data for exclusive ρ photoproduction at HERA, when combined with lower-energy data [2] lead to a slope α ′ for the trajectory of the soft pomeron that differs significantly from the classical value α ′ = 0.25 GeV −2 . A main message of this paper is to disagree with this conclusion; we show that in fact the classical value is confirmed by the data.

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Photoproduction of ϱ0 and ω on hydrogen at photon energies of 20 to 70 GeV

Cited by 57 publications

References 22 publications

Diffractive electroproduction of ρ and ϕ mesons at HERA

Diffractive electroproduction of ρ and ϕ mesons at HERA

Exclusive diffractive processes and the quark substructure of mesons

Exclusive vector photoproduction: confirmation of Regge theory

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