Date

Inclusive photoproduction of $\pi^0$ mesons at 6 GeV

Berger, Christoph ; Dick, G. ; Erlewein, W. ; et al.
Phys.Lett.B 47 (1973) 377-380, 1973.
Inspire Record 95414 DOI 10.17182/hepdata.45246

An experiment has been performed to study the inclusive photoproduction of π 0 mesons. Photoproduced π 0 's were detected in a hodoscope consisting of 14 lead glass Cerenkov counters. To obtain the cross sections at a photon energy of 6 GeV we used the photon-difference method. Data are presented in terms of the Feynman variable x = q ‖ ∗ (√s/2) and the trnasverse momentum q⊥. We have measured four q ⊥ distributions at x = 0.2, 0.4, 0.6 and 0.8. The results dhow that the π 0 rate at small values of q ⊥ is smaller than the π± rate. The data can be fitted smoothly by a form A exp (− Bq ⊥ 2 ) with a value about 3.5 GeV −2 for the slope parameter B .

4 data tables

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Updated Charged-Particle Multiplicity Distribution from 205-GeV/c Proton Proton Interactions

Barish, S. ; Cho, Y. ; Colley, D.C. ; et al.
Phys.Rev.D 9 (1974) 2689, 1974.
Inspire Record 609 DOI 10.17182/hepdata.21974

The charged-particle multiplicity distribution in 205−GeVc proton-proton interactions is presented. In addition, the total diffractive contributions to each charged multiplicity are estimated assuming a factorizable Pomeron.

1 data table

THE TOTAL CROSS SECTION NORMALIZATION COMES FROM THIS AND OTHER EXPERIMENTS.


Measurements of the differential cross-section of the reaction p p ---> d pi+ from 3.0 to 5.0 gev/c

Anderson, H.L. ; Larson, D.A. ; Myrianthopoulos, L.C. ; et al.
Phys.Rev.D 9 (1974) 580-596, 1974.
Inspire Record 93111 DOI 10.17182/hepdata.21941

A measurement of the complete differential cross section for the reaction pp→dπ+ at 3.00, 3.20, 3.43, 3.65, 3.83, 4.00, 4.20, and 5.05 GeVc incident proton momentum has been made in an attempt to establish the role of the Δ (1950) in this region. The data show that the previously observed enhancement in the forward cross section between 3 and 4 GeVc due to this isobar is an effect which damps out quickly as the production angle departs from zero degrees, in contrast with the well-known enhancement at 1.35 GeVc, which is evident at all angles. In particular, the one-pion-exchange model is in poor agreement with the extended set of data. A detailed description is given of a novel proportional-wire-chamber system which facilitated the selection of this rather rare reaction from a very high competing background.

3 data tables

Axis error includes +- 6/6 contribution.

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Measurements of d p backward elastic scattering at 3.43, 4.50, 5.75, and 6.60 gev/c incident deuteron momentum

Dubal, L. ; Hargrove, C.K. ; Hincks, E.P. ; et al.
Phys.Rev.D 9 (1974) 597-603, 1974.
Inspire Record 93110 DOI 10.17182/hepdata.21938

Differential cross sections for dp elastic scattering from 60° to 175° center of momentum (c.m.) were measured at 3.43, 4.50, 5.75, and 6.60 GeVc incident deuteron momentum. The measurements were made with a two-arm magnetic spectrometer, making use of multiwire proportional chamber detectors. The deuterons were accelerated at the Bevatron of the Lawrence Berkeley Laboratory. Data are compared with predictions of the baryon-pickup model and the one-pion-exchange model. The backward dip at 180° c.m. for 4.5 GeVc, predicted by Craigie and Wilkin using the one-pion-exchange model, is not observed, but reasonable fits to the momentum variation and angular distributions are found. When the data are plotted against the variable Δ of the baryon-pickup model, the s dependence is greatly reduced.

4 data tables

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Measurement of the polarization parameter in k+ p elastic scattering

Barnett, B.A. ; Laasanen, A.T. ; Koehler, P.F.M. ; et al.
Phys.Rev.D 8 (1973) 2751-2764, 1973.
Inspire Record 93326 DOI 10.17182/hepdata.22081

Full angular distributions of the polarization parameter in elastic K+p scattering at 1.37, 1.45, 1.60, 1.71, 1.80, 1.89, 2.11, and 2.31 GeV/c are presented. These data were obtained in an experiment at the Zero Gradient Synchrotron using a polarized proton target with arrays of scintillation and Čerenkov counters to detect the scattered particles.

8 data tables

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Topological and Leading Particle Cross-Sections for 147-GeV/c $\pi^- p$ Interactions.

Fong, D.G. ; Heller, M. ; Shapiro, A.M. ; et al.
Phys.Lett.B 53 (1974) 290-296, 1974.
Inspire Record 93415 DOI 10.17182/hepdata.27916

Results are reported based on a study of π − p interactions at 147 GeV/ c in the FERMILAB 30-inch Proportional Wire Hybrid Bubble Chamber System. We have measured the topological cross sections and separated two-prong elastic and inelastic channels. In addition, we have extracted leading particle cross sections using the increased momentum resolution of the downstream proportional wire chambers. We have compared our results with experiments and predictions of a simple fragmentation hyphothesis.

1 data table

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Observation of Structure in anti-p p and anti-p d Total Cross-Sections Below 1.1-GeV/c

Carroll, A.S. ; Chiang, I.-H. ; Kycia, T.F. ; et al.
Phys.Rev.Lett. 32 (1974) 247, 1974.
Inspire Record 567 DOI 10.17182/hepdata.21309

Total cross sections of p¯p and p¯d have been measured between 360 and 1050 MeV/c, with high statistical precision. Structures are observed in both cross sections at about the same momenta. For p¯p, the central mass is 1932±2 MeV/c2, and a fit to the data with a simple Breit-Wigner resonance plus background gives Γ=9−3+4 MeV/c2. The data suggest that the structures are in the isospin-1 state.

1 data table

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Negative-pion photoproduction from neutrons by linearly polarized photons in the first resonance region

Kondo, K. ; Miyachi, T. ; Ukai, K. ; et al.
Phys.Rev.D 9 (1974) 529-533, 1974.
Inspire Record 93115 DOI 10.17182/hepdata.21954

The angular dependence of the asymmetry for negative-pion photoproduction on neutrons by linearly polarized photons has been measured for photon energies 260, 300, 350, 400, 450, and 500 MeV at center-of-mass angles 60°, 75°, 90°, 150°, and 120°. The results are compared with theoretical models of low-energy single-pion photoproduction. The observed asymmetry below 400 MeV shows good agreement with predictions of dispersion-theoretical models by Berends, Donnachie, and Weaver and by Schwela. The asymmetry values in the 400-500 MeV energy region suggest that smaller M1− amplitude is more favorable.

6 data tables

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Analysis of Two Prong Events on p p Interactions at 205-GeV/c: Separation of Elastic and Inelastic Events.

Barish, S. ; Colley, D. ; Derrick, M. ; et al.
Phys.Rev.D 9 (1974) 1171-1179, 1974.
Inspire Record 93436 DOI 10.17182/hepdata.21998

We present results of complete measurements of the two-prong events observed in a 50 000-picture exposure of the 30-in. hydrogen bubble chamber to a 205−GeVc proton beam at the National Accelerator Laboratory. Using kinematic fitting, elastic and inelastic events are separated and cross sections are obtained. The total two-prong cross section is measured to be 9.77 ± 0.40 mb, of which 2.85 ± 0.26 mb represents the inelastic contribution. The total elastic cross section is measured to be 6.92 ± 0.44 mb. Our data are consistent with the break in dσdt at |t|∼0.1−0.2 (GeVc)2 observed at the CERN ISR. A prominent low-mass enhancement is observed in the distribution of missing mass squared from the slow proton for the inelastic events. An analysis based on the missing-mass spectrum and the particle rapidities shows that this low-mass enhancement accounts for about 77% of the total inelastic two-prong cross section. The diffractive cross section in the two-prong events is 2.20 ± 0.25 mb, in agreement with certain two-component models.

2 data tables

USING A TOTAL CROSS SECTION OF 39.0 +- 1.0 MB.

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Study of the reaction p d ---> he-3 x0

Brody, H. ; Groves, E. ; Van Berg, R. ; et al.
Phys.Rev.D 9 (1974) 1917-1932, 1974.
Inspire Record 92993 DOI 10.17182/hepdata.21985

The missing-mass technique has been used to study the spectra of neutral mesons produced by 2- and 3-Gev protons in the reaction p+d→He3+x0. Cross sections (dσdΩc.m.) of about 10−34 cm2/sr were observed for the π, η, and ω for 3-GeV protons. A peak with a much smaller cross section was observed at a mass of 956 MeV. We have tentatively identified this peak as the η′. Cross sections for the π and η were nearly a factor of 10 larger at 2 GeV than at 3 GeV. Deviations from simple phase space were observed near the two-pion threshold in both 2-GeV and 3-GeV data. Details of the experimental method and of the results are presented.

1 data table

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