Date

Single pi- photoproduction on neutrons in the energy region of the p(11), d(13), s(11) pion-nucleon resonances

Beneventano, M. ; D' Angelo, S. ; De Notaristefani, F. ; et al.
Nuovo Cim.A 19 (1974) 529-547, 1974.
Inspire Record 96708 DOI 10.17182/hepdata.37753

In this note we report the results obtained in a single-photoproduction experiment on neutrons in deuterium, with an experimental apparatus made of scintillation counters, spark chambers and a magnetic spectrometer; the explored energy region is one around the second resonance, that is (500÷900) MeV indicent γ-ray energy. We briefly describe the present situation of the phenomenological analysis of the single photoproduction in the second resonance region and compare the results of an analysis made by us with the results obtained by other authors; in particular the e.m. coupling of theP11 isobaric state found by us is large, in accordance with the results of some other authors.

1 data table

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Evidence for the omega pi pi decay modes of the a2 and omega(1675)

Diaz, J. ; Dibianca, F.A. ; Fickinger, W.J. ; et al.
Phys.Rev.Lett. 32 (1974) 260-264, 1974.
Inspire Record 94695 DOI 10.17182/hepdata.21339

We present evidence for the decay A20→ωπ+π0 with a branching ratio Γ(A2→ωππ)Γ(A2→ρπ)=0.28±0.09 and for the decay ω(1675)→ωπ+π− with a branching ratio Γ(ω(1975)→ωπ+π−)Γ(ω(1675)→ρπ)=0.47±0.18. Evidence is given for an intermediate B(1235)π state in the ω(1675) decay.

2 data tables

FITTED WITH BREIT-WIGNER RESONANCES PLUS BACKGROUND.

BACKGROUND SUBTRACTED TP DISTRIBUTIONS.


Investigation of the reaction pi- p ---> omega0 n at 3.65, 4.50, and 5.50 gev/c

Holloway, L.E. ; Huld, B. ; Jordan, M. ; et al.
Phys.Rev.D 8 (1973) 2814-2826, 1973.
Inspire Record 93327 DOI 10.17182/hepdata.22060

An experiment using optical spark chambers and a neutron time-of-flight hodoscope has been performed at the Argonne National Laboratory on the reaction π−p→ω0n. The differential cross section and the experimentally accessible density-matrix elements were determined in the momentum transfer interval 0.05≤|t|≤1.0 (GeV/c)2 at each of three incident pion momenta 3.65, 4.50, and 5.50 GeV/c. Our results show the following general features: (1) a dip in the forward differential cross section for |t|≤0.2 (GeV/c)2, (2) a slope at larger momentum transfers which increases as the incident pion momentum increases, and (3) no dips in either dσdt or ρ11+ρ1−1, the natural-parity exchange combination, at |t|=0.6 (GeV/c)2.

2 data tables

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Search for neutral mesons near 1 gev/c-squared

Binnie, D.M. ; Camilleri, L. ; Carr, J. ; et al.
Phys.Rev.Lett. 32 (1974) 392-395, 1974.
Inspire Record 94572 DOI 10.17182/hepdata.21308

In a study of the missing-mass spectrum near 1 GeV in the reaction π−+p→MM+n at three incident momenta near 2 GeV, we find no evidence for the recently reported narrow neutral mesons at 940, 963, and 1033 MeV.

1 data table

No description provided.


Differential cross-section for backward pi+ p scattering from 3.25 to 10 gev/c

Bashian, A. ; Finocchiaro, G. ; Good, M.L. ; et al.
Phys.Rev.D 9 (1974) 3193-3196, 1974.
Inspire Record 94286 DOI 10.17182/hepdata.21973

We present differential cross-section data for the reaction π+p→π+p near 180° in the center-of-mass system at beam momenta between 3.25 GeVc and 10 GeVc.

2 data tables

No description provided.

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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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The Discovery of a Second Narrow Resonance in e+ e- Annihilation

Abrams, G.S. ; Briggs, D. ; Chinowsky, William ; et al.
Phys.Rev.Lett. 33 (1974) 1453-1455, 1976.
Inspire Record 91611 DOI 10.17182/hepdata.21287

We have observed a second sharp peak in the cross section for e+e−→hadrons at a center-of-mass energy of 3.695±0.004 GeV. The upper limit of the full width at half-maximum is 2.7 MeV.

1 data table

No description provided.


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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Direct evidence for the s* meson near the k anti-k threshold

Binnie, D.M. ; Carr, J. ; Debenham, N.C. ; et al.
Phys.Rev.Lett. 31 (1973) 1534-1537, 1973.
Inspire Record 94702 DOI 10.17182/hepdata.48037

We report observation of the S* meson in the reaction π−+p→S*+n. The S* decays into ππ and KK and is seen most clearly in the 2π0 channel. A fit to the data gives a sheet-II pole at 987±7−i(24±7) MeV and a relative coupling gS→KKgS→ππ of 3.8 ± 1.0.

1 data table

AT AROUND K+ K- THRESHOLD.


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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