HEPData Search

We present density-matrix elements and single-spin correlations for the reaction p↑p→pπ+n at 3, 4, 6, and 11.75 GeV/c, using both longitudinal and transverse beam polarizations. For small momentum transfers, the spin correlations are mainly due to off-shell π+p elastic scattering, while for larger t there are large polarization effects associated with the production dynamics for p↑p→Δ++n. Comparison of longitudinal and transverse polarization correlations suggests that the Δ++-production spin effects are due mainly to unnatural-parity exchanges. We present a model-dependent amplitude analysis, and extract the energy dependence of the natural- and unnatural-parity-exchange contributions.

36 data tables match query

Table 1

Unpolarized cross sections.

Table 2

Unpolarized cross sections.

Table 3

Unpolarized cross sections.

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PHOTOPRODUCTION OF eta MESONS AT 9.7-GeV

Nelson, C.A., Jr. ; Abramson, J. ; Andrews, D.E. ; et al.

Phys.Rev.D 19 (1979) 1931, 1979.

Inspire Record 132567 DOI 10.17182/hepdata.24307

Inclusive η photoproduction has been studied at 9.7 GeV, on hydrogen and deuterium targets. A simple, parameter-free ρ0-dominance model adequately fits the forward cross sections, but overestimates the cross section at large momentum transfer.

1 data table match query

Table 1

No description provided.

Inelastic Photoproduction of omega and rho+- Mesons

Nelson, C.A., Jr. ; May, E.N. ; Abramson, J. ; et al.

Phys.Rev.D 17 (1978) 647, 1978.

Inspire Record 4373 DOI 10.17182/hepdata.24401

We report measurements of inelastic photoproduction of ω and ρ± mesons from hydrogen and deuterium at incident photon energies in the range 7.5-10.5 GeV. For ωΔ and ρ−Δ++ production, differential cross sections dσdt′ and spin density matrices are presented. For higher missing masses the cross sections dσdMX2 and invariant structure functions F(x) are also given. The data are compared to a one-pion-exchange model. We conclude that pion exchange is dominant for inelastic ω photoproduction, but unimportant for ρ±.

4 data tables match query

Table 1

CROSS SECTION PER NUCLEON FOR COMBINED HYDROGEN AND DEUTERIUM DATA ALLOWING FOR A GLAUBER CORRECTION FACTOR OF 0.88 FOR THE DEUTERIUM CROSS SECTIONS.

Table 2

HYDROGEN AND DEUTERIUM DATA COMBINED BY AVERAGING.

Table 3

OBTAINED BY EXTRAPOLATING A FIT TO D(SIG)/DT OVER -T = 0 TO 0.52 GEV**2.

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SEARCH FOR LAMBDA p STATES IN THE BARYON EXCHANGE REACTION p p ---> LAMBDA p K+ AT 11.75-GeV/c

Arenton, M.W. ; Ayres, D.S. ; Diebold, R. ; et al.

Phys.Rev.D 28 (1983) 657, 1983.

Inspire Record 188917 DOI 10.17182/hepdata.23770

We have obtained 1400 events of the baryon-exchange reaction pp→ΛpK+ using the ANL Zero Gradient Synchrotron 11.75-GeV/c polarized proton beam and the effective-mass spectrometer. A search for enhancements in the Λp mass spectrum has been made. No enhancements are observed; in particular, the narrow Λp enhancement at 2.13 GeV seen in K−d→Λpπ− is not observed. We establish limits on the production of narrow states of ∼ 10 nb. Also, 100000 events of the forward reaction pp→ΛK+p were examined and no narrow Λp enhancements are seen.

2 data tables match query

Table 1

No description provided.

Table 2

No description provided.

Measurement of $J/\psi$ and $\psi^\prime$ Real Photoproduction on $^{6}$Li at a Mean Energy of 90-{GeV}

The NA14 collaboration Barate, R. ; Bareyre, P. ; Bloch, D. ; et al.

Z.Phys.C 33 (1987) 505, 1987.

Inspire Record 235579 DOI 10.17182/hepdata.15814

Inelastic and elasticJ/ψ (3097) photoproduction on Li6 are measured at a mean γ energy of 90 GeV in an open spectrometer. TheJ/ψ are identified by their decays intoμ+μ− ore+e−. A signal of ψ′(3685) intoμ+μ− andJ/ψπ+π− is also seen. The inelastic cross-section withZ=Eψ/Eγ<0.9 is compared in shape and magnitude with the colour singlet model of photon-gluon fusion.

2 data tables match query

Table 1

DIMUON TRIGGER, INELASTIC MEANS Z < 0.9.

Table 2

ELECTRON TRIGGER, INELASTIC MEANS Z < 0.9.

Estimate of the Delta(1232) component in the C-12 nucleus

Bystritsky, V.M. ; Glavanakov, I.V. ; Grabmayr, P. ; et al.

JETP Lett. 73 (2001) 453-456, 2001.

Inspire Record 563307 DOI 10.17182/hepdata.16707

The cross section for the 12C(γ, π+ p) reaction was measured in the range of the Δ(1232) isobar. The data were analyzed using the models taking into account the nucleon and isobaric degrees of freedom of the 12C nucleus. The conclusion is drawn that in the large-momentum transfer range the π+ p pairs are produced in the course of the direct knocking-out of Δ++ isobar from the nucleus. The probability of finding the Δ isobar in the ground-state 12C nucleus is estimated at 0.018±0.005 Δ isobars per nucleon.

1 data table match query

Table 1

The accuracy of the proton energy measurement = 4 MeV. The accuracy of the proton angles: DTHETA = 3 deg and DPHI = 2 deg. The background events < 3 pct for 450 MeV GAMMA energy (500 MeV of electron energy) and negligible for 400 MeV beam (420 MeV of electron energy). The estimation of the probability of finding DELTA in the ground state of C12 nucleus equals 0.018 +- 0.005 DELTA/nucleon.