Photoproduction of $\omega$ mesons off protons and neutrons

The CBELSA/TAPS collaboration Dietz, F. ; Metag, V. ; Anisovich, A.V. ; et al.
Eur.Phys.J.A 51 (2015) 6, 2015.
Inspire Record 1340913 DOI 10.17182/hepdata.69767

ω photoproduction off hydrogen and deuterium has been studied with the tagged photon beam of the ELSA accelerator in Bonn for photon energies up to 2.0 GeV. The ω meson has been identified via the ω → π$^{0}$ γ → γγγ decay mode, using the combined setup of the Crystal Barrel/TAPS detector systems. Both inclusive and exclusive analyses have been carried out. Differential and total cross-sections have been derived for ω mesons produced off free protons and off protons and neutrons bound in deuterium. The cross-section for the production off the bound neutron is found to be a factor of ≈ 1.3 larger than the one off the bound proton in the incident beam energy region 1.2 GeV < E$_{γ}$ < 1.6 GeV. For higher incident beam energies this factor goes down to ≈ 1.1 at 2.0 GeV. The cross-sections of this work have been used as normalization for transparency ratio measurements.

85 data tables

Differential cross-sections of $\omega$ mesons produced off the free proton versus $\cos(\theta^\omega_{\mathrm{c.m.}})$ and versus the momentum transfer to the nucleon, $t$, for incident photon energy $E_\gamma$ = 1.125-1.150 GeV.

Differential cross-sections of $\omega$ mesons produced off the free proton versus $\cos(\theta^\omega_{\mathrm{c.m.}})$ and versus the momentum transfer to the nucleon, $t$, for incident photon energy $E_\gamma$ = 1.150-1.175 GeV.

Differential cross-sections of $\omega$ mesons produced off the free proton versus $\cos(\theta^\omega_{\mathrm{c.m.}})$ and versus the momentum transfer to the nucleon, $t$, for incident photon energy $E_\gamma$ = 1.175-1.200 GeV.

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Photoproduction of eta-mesons off nuclei for Eg < 2.2 GeV

The CBELSA & TAPS collaborations Mertens, T. ; Jaegle, I. ; Muhlich, P. ; et al.
Eur.Phys.J.A 38 (2008) 195-207, 2008.
Inspire Record 799499 DOI 10.17182/hepdata.50323

Photoproduction of $\eta$ mesons off $^{12}$C, $^{40}$Ca, $^{93}$Nb, and $^{nat}$Pb nuclei has been measured with a tagged photon beam with energies between 0.6 and 2.2 GeV. The experiment was performed at the Bonn ELSA accelerator with the combined setup of the Crystal Barrel and TAPS calorimeters. It aimed at the in-medium properties of the S$_{11}$(1535) nucleon resonance and the study of the absorption properties of nuclear matter for $\eta$ mesons. Careful consideration was given to contributions from $\eta\pi$ final states and secondary production mechanisms of $\eta$-mesons e.g. from inelastic $\pi N$ reactions of intermediate pions. The analysis of the mass number scaling shows that the nuclear absorption cross section $\sigma_{N\eta}$ for $\eta$ mesons is constant over a wide range of the $\eta$ momentum. The comparison of the excitation functions to data off the deuteron and to calculations in the framework of a BUU-model show no unexplained in-medium modifications of the S$_{11}$(1535).

10 data tables

Inclusive energy distribution for incident photon energy 0.650 to 0.835 GeV.

Inclusive energy distribution for incident photon energy 0.835 to 1.050 GeV.

Inclusive energy distribution for incident photon energy 1.050 to 1.550 GeV.

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K^0 pi^0 Sigma^+ and K^*0 Sigma^+ photoproduction off the proton

The CBELSA/TAPS collaboration Nanova, M. ; Bacelar, J.C.S. ; Bantes, B. ; et al.
Eur.Phys.J.A 35 (2008) 333-342, 2008.
Inspire Record 781382 DOI 10.17182/hepdata.51372

The exclusive reactions $\gamma p \to K^{*0} \Sigma^+(1189)$ and $\gamma p \to K^{0} \pi^{0}\Sigma^+(1189)$, leading to the p 4$\pi^{0}$ final state, have been measured with a tagged photon beam for incident energies from threshold up to 2.5 GeV. The experiment has been performed at the tagged photon facility of the ELSA accelerator (Bonn). The Crystal Barrel and TAPS detectors were combined to a photon detector system of almost 4$\pi$ geometrical acceptance. Differential and total cross sections are reported. At energies close to the threshold, a flat angular distribution has been observed for the reaction $\gamma p\to K^{0} \pi^{0}\Sigma^+$ suggesting dominant s-channel production. $\Sigma^*(1385)$ and higher lying hyperon states have been observed. An enhancement in the forward direction in the angular distributions of the reaction $\gamma p \to K^{*0}\Sigma^+$ indicates a $t$-channel exchange contribution to the reaction mechanism. The experimental data are in reasonable agreement with recent theoretical predictions.

13 data tables

Differential cross section D(SIG)/DCOS(THETA(SIG+)) for the GAMMA P --> K0 PI0 SIGMA+ reaction for beam energies 1500-1700 and 1700-1850 MeV.

Differential cross section D(SIG)/DCOS(THETA(SIG+)) for the GAMMA P --> K0 PI0 SIGMA+ reaction for beam energies 1850-2000 and 2000-2150 MeV.

Differential cross section D(SIG)/DCOS(THETA(SIG+)) for the GAMMA P --> K0 PI0 SIGMA+ reaction for beam energies 2150-2300 and 2300-2500 MeV.

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Large-angle elastic pion proton scattering at momenta 0.9-GeV/c to 2.0-GeV/c.

Abramov, B.M. ; Bulychjov, Sergey A. ; Dukhovskoi, I.A. ; et al.
Sov.J.Nucl.Phys. 54 (1991) 332-337, 1991.
Inspire Record 318074 DOI 10.17182/hepdata.39980

None

11 data tables

THE MOMENTUM OF EACH INCIDENT PION WAS DETERMINED WITH AN ACCURACY 0.2 PCT.

THE MOMENTUM OF EACH INCIDENT PION WAS DETERMINED WITH AN ACCURACY 0.2 PCT.

THE MOMENTUM OF EACH INCIDENT PION WAS DETERMINED WITH AN ACCURACY 0.2 PCT.

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THE H-3 + P ---> P + N + D REACTION AT A TRITIUM MOMENTUM OF 5-GEV/C

Abdullin, S.K. ; Blinov, A.V. ; Vanyushin, I.A. ; et al.
Nucl.Phys.A 506 (1990) 471-481, 1990.
Inspire Record 297384 DOI 10.17182/hepdata.15700

Using a liquid hydrogen bubble chamber of the ITEP, 80 cm in diameter, a study was made of the 3 H + p → p + n + d reaction with an incident momentum of 5 GeV/c for the tritium nuclei. The reaction cross section was 20.4 ± 0.2 mb. The angular, momentum and mass distributions of the reaction products in the 4π geometry have been obtained. We have separated the phase-space regions corresponding to quasi-free pn scattering and to the final-state Nd interaction. In the region of quasi-free pn scattering various experimental spectra are compared with the theoretical predictions, by using pole diagrams with nuclear vertex functions for three NN potentials: the Yamaguchi potential, the RSC potential and the potential in the quark-compound bag model. In the mass spectra of pn, pd and nd systems no evidence for the exhibition of two- and three-baryon resonances has been obtained.

6 data tables

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STUDY OF SPIN ALIGNMENT OF rho0 (770) MESON in K- p AND p p INTERACTIONS AT 32-GeV/c

Babintsev, V.V. ; Borovikov, A.A. ; Vinitsky, A.A. ; et al.
53-59, 1983.
Inspire Record 193854 DOI 10.17182/hepdata.31044

None

3 data tables

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A STUDY OF DELTA++ AND DELTA0 ISOBAR INCLUSIVE PRODUCTION IN K- p INTERACTIONS AT 32-GeV/c

Babintsev, V.V. ; Bogolyubsky, M.Yu. ; Bumazhnov, V.A. ; et al.
Sov.J.Nucl.Phys. 39 (1984) 414, 1984.
Inspire Record 190556 DOI 10.17182/hepdata.41019
22 data tables

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EVENTS WITH IDENTIFIED PROTONS.

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ANALYSIS OF THE REACTION He-3 p ---> p p d AT 5-GeV/c He-3 NUCLEUS MOMENTUM

Blinov, A.V. ; Chuvilo, I.V. ; Ergakov, V.A. ; et al.
1981.
Inspire Record 169669 DOI 10.17182/hepdata.40248
10 data tables

DATA WITHOUT MOMENTUM REJECTION.

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Determination of Nucleon and Pion Form-factors by Analyzing the $\pi^- p \to e^+ e^- \pi$ Reaction at E ($\pi$) = 164-{MeV}

Alizade, V.V. ; Berezhnev, S.F. ; Blokhintseva, T.D. ; et al.
Sov.J.Nucl.Phys. 33 (1981) 189, 1981.
Inspire Record 154897 DOI 10.17182/hepdata.39237

None

3 data tables

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Inclusive Production of $\rho^0$ and $\phi$ in $K^+ p$ Interactions at 32-{GeV}/c

The Soviet-CERN collaboration Vorobjev, A.P. ; Gerdyukov, L.N. ; Knyazev, V.V. ; et al.
Nucl.Phys.B 176 (1980) 303, 1980.
Inspire Record 153559 DOI 10.17182/hepdata.48999

Inclusive ϱ 0 and φ production is investigated in K + p interactions at 32 GeV/ c . Total and semi-inclusive ϱ 0 and φ cross sections, longitudinal and transverse momentum distributions, including 〈 P T versus x dependence are presented. No evidence for a sea-gull effect is observed. Comparison with quark models strongly suggests the possibility that a large fraction of the ϱ 0 and vector mesons are produced as fragmentation products of the incident particles. Study of uncorrelated π + π − pairs in the ϱ 0 mass range provides possible indirect evidence for the existence of diquarks in the proton.

39 data tables

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