Photoproduction
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$J/\psi$ Photoproduction from 60-GeV/c to 300-GeV/c

Binkley, Morris E. ; Bohler, C. ; Butler, J. ; et al.
Phys.Rev.Lett. 48 (1982) 73, 1982.
Inspire Record 168767 DOI 10.17182/hepdata.20597

Measurements of the energy and t dependence of diffractive Jψ photoproduction are presented. A significant rise in the cross section over the energy range 60-300 GeV is observed. It is found that (30±4)% of the events are inelastic.

1 data table
Table 1

No description provided.


$\Lambda^{0}$ polarization from the reaction $\gamma + p=K^{+} + \Lambda^{0}$ in the energy range (950÷1050) MeV

Borgia, B. ; Grilli, M. ; Joos, P. ; et al.
Nuovo Cim. 32 (1964) 218-223, 1964.
Inspire Record 1185014 DOI 10.17182/hepdata.37674

None

1 data table
Table 1

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


A MEASUREMENT OF THE DIFFERENCE BETWEEN THE SINGLE NUCLEON CROSS-SECTIONS FOR j / psi MUOPRODUCTION IN IRON AND IN H-2, D-2 TARGETS

The European Muon collaboration Aubert, J.J. ; Bassompierre, G. ; Becks, K.H. ; et al.
Phys.Lett.B 152 (1985) 433-438, 1985.
Inspire Record 207459 DOI 10.17182/hepdata.30432

The cross sections for J ψ production have been measured in interactions of 280 GeV μ + on hydrogen and deuterium (H, D) and also in interactions of 250 GeV μ + on iron. The single-nucleon cross sections in iron are found to be larger than those in H, D. The mean ratio of the iron to H, D photoproduction cross sections in the range 60 < v < 200 GeV is 1.45 ±0.12 (statistical) ±0.22 (systematic error). Within the framework of the photon-gluon fusion model, this indicates that the gluon density per nucleon is ∼45% larger in iron than in H, D in the range 0.026 < x < 0.085, on a mass scale Q 2 eff ∼M 2 J ψ .

3 data tables
Table 1

First table is from combined H and DEUT data at 280 Gev. Second table is from FE data at 250 Gev.

Table 2

First table is from combined H and DEUT data at 280 Gev. Second table is from FE data at 250 Gev.

Table 3

THIS TABLE IS THE RATIO OF THE EFFECTIVE GLUON DISTRIBUTIONS IN IRON AND HYDROGEN(DEUTERIUM) ASSUMING THAT PHOTON-GLUON FUSION IS THE RELEVANT MECHANISM FOR J/PSI PRODUCTION.


A MEASUREMENT OF THE TOTAL HADRONIC CROSS-SECTION IN TAGGED gamma gamma REACTIONS

The TPC/Two Gamma collaboration Aihara, H. ; Alston-Garnjost, M. ; Avery, R.E. ; et al.
Phys.Rev.D 41 (1990) 2667, 1990.
Inspire Record 281351 DOI 10.17182/hepdata.22991

We present a measurement of the total cross section for γγ→hadrons, with one photon quasireal and the other a spacelike photon of mass squared −Q2. Results are presented as a function of Q2 and the γγ center-of-mass energy W, with the Q2 range extending from 0.2 to 60 GeV2, and W in the range from 2 to 10 GeV. The data were taken with the TPC/Two-Gamma facility at the SLAC e+e− storage ring PEP, which was operated at a beam energy of 14.5 GeV. The cross section exhibits a gentle falloff with increasing W. Its Q2 dependence is shown to be well described by an incoherent sum of vector-meson and pointlike scattering over most of the observed W range. Agreement at high Q2 is improved if a minimum-pT cutoff (motivated by QCD) is imposed on the pointlike contribution.

4 data tables
Table 1

Errors are statistical only.

Table 2

Errors are statistical only.

Table 3

Errors are statistical only.

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A Measurement of $\gamma \gamma \to \rho^+ \rho^-$

The ARGUS collaboration Albrecht, H. ; Bockmann, P. ; Glaser, R. ; et al.
Phys.Lett.B 217 (1989) 205-210, 1989.
Inspire Record 266416 DOI 10.17182/hepdata.29853

The reaction γγ → ϱ + ϱ − → π + π − π 0 π 0 has been studied with the ARGUS detector at the e + e − storage ring DORIS II at DESY. Near threshold, the cross section for this reaction is about four times smaller than for the reaction γγ → ϱ 0 ϱ 0 .

4 data tables
Table 1

Data read from graph.

Table 2

Data read from graph.

Table 3

Data read from graph.

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A Measurement of Elastic $J / \psi$ Photoproduction Cross Section at Fermilab E687

The E687 collaboration Frabetti, P.L. ; Paolone, V.S. ; Yager, P.M. ; et al.
Phys.Lett.B 316 (1993) 197-206, 1993.
Inspire Record 359356 DOI 10.17182/hepdata.28834

Measurements of elastic photoproduction cross sections for the J / ψ meson from 100 GeV to 375 GeV are presented. The results indicate that the cross section increases slowly in this range. The shape of the energy dependence agrees well with the photon-gluon fusion model prediction.

3 data tables
Table 1

Data supplied by V. Paolone.

Table 2

Cross section data using Bethe-Heitler event normalization.

Table 3

Cross section data using the Beam Gamma Monitor normalization.


A Measurement of the $Q^2$ and $W$ Dependence of the $\gamma \gamma$ Total Cross-section for Hadron Production

The PLUTO collaboration Berger, Christoph ; Deuter, A. ; Genzel, H. ; et al.
Z.Phys.C 26 (1984) 353, 1984.
Inspire Record 204849 DOI 10.17182/hepdata.16195

A measurement of the γγ total cross section, σγγ(Q2W), is presented for theQ2 range 0.1 to 100 GeV2, and for the massW of the hadronic final state between 1.5 and 10 GeV. The dependence of σγγ on bothQ2 andW is measured. The results are compared with theoretical predictions. It is found that the data are well described by a sum of quarkparton model and vector dominance contributions.

4 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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A Measurement of the Reaction $e^+ e^- \to e^+ e^- \eta^\prime$ and the Radiative Width $\Gamma (\eta^\prime \to \gamma \gamma$) at {PETRA}

The JADE collaboration Bartel, W. ; Cords, D. ; Dittmann, P. ; et al.
Phys.Lett.B 113 (1982) 190-194, 1982.
Inspire Record 177090 DOI 10.17182/hepdata.30958

The reaction e + e - → e + e - η' has been observed in the JADE experiment at PETRA, by detecting the final state π + π - γ, resulting from the decay η' → γϱ 0 . The cross section was measured at an average beam energy of 17.15 GeV to be σ(e + e - → e + e - η') = 2.2 ± 0.2 (stat.) ± 0.4(syst.) nb, yielding the radiative width Γ η'γγ = 5.0 ± 0.5(stat.) ± 0.9 (syst.) keV.

1 data table
Table 1

No description provided.


A Measurement of the form-factors of light pseudoscalar mesons at a large momentum transfer

The CLEO collaboration Savinov, Vladimir ;
203-208, 1995.
Inspire Record 397179 DOI 10.17182/hepdata.18789

Using the CLEO-II detector, we have studied the exclusive two-photon production of the light pseudoscalar mesons in a single tagged mode. We report on a preliminary measurement of the $\pi~0$, $\eta$ and $\eta~{\prime}$ electromagnetic form factors in the $Q~2$ region from 2 ${\rm (GeV/c)}~2$ to 20 ${\rm (GeV/c)}~2$.}

4 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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A Measurement of the pi0, eta and eta-prime electromagnetic form-factors

The CELLO collaboration Behrend, H.J. ; Criegee, L. ; Field, J.H. ; et al.
Z.Phys.C 49 (1991) 401-410, 1991.
Inspire Record 299282 DOI 10.17182/hepdata.45172

We present measurement of the π0γ*γ, ηγ*γ and η′γ*γ form factors. The π0-form factor is for the first time observed in the space-like region. The transition form factor of the η-meson is determined from its decay modes π+π−π0, π+π−γ and the neutral decay mode γγ. The decay of the η′ is observed in the decay channels ργ, ηπ+π− with η→γγ and in the four charged prong final state stemming from ηπ+π− with the η decaying into π+π−(π0/γ). All form factors agree well with a simple ρ-pole predicted by the vector meson dominance model and also with the QCD inspired Brodsky-Lepage model.

4 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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