Differential Cross-Sections for the Charge Exchange Process pi+ p ---> pi0 (pi+ p) at 8-GeV/c, 16-GeV/c and 23-GeV/c

The Aachen-Berlin-Bonn-CERN-Cracow-Heidelberg collaboration Baker, P A ; Barnham, Keith W.J. ; Buschbeck, Brigitte ; et al.
Nucl.Phys.B 85 (1975) 31-38, 1975.
Inspire Record 90862 DOI 10.17182/hepdata.32119

The differential cross section d σ d t′ for the charge-exchange process π + p → π 0 ( π + p) at 8, 16 and 23 GeV/ c is presented for several regions of the π + p effective mass. It is found that the dip at t ′ ≈ 0.6 (GeV/ c ) 2 which is observed in the Δ(1236) mass band becomes a less pronounced structure in the higher mass regions. However, while the slope of the d σ d t′ distributions in the near-forward direction decreases strongly with increasing π + p mass, there is no evidence that the observed structure moves to higher values of t ′ as the π + p mass increases. These results are consistent with a Regge-exchange picture where the position of the dip is determined by the exchanged trajectory, but are inconsistent with a simple geometrical picture.

1 data table

TP DEPENDENCE FOR FOUR <PI+ P> MASS INTERVALS.


Prism plot - a new analysis of multibody final states

Brau, J.E. ; Dao, F.T. ; Hodous, M.F. ; et al.
Phys.Rev.Lett. 27 (1971) 1481-1485, 1971.
Inspire Record 68878 DOI 10.17182/hepdata.21501

We present a new technique for analyzing multibody states. This analysis makes possible the selection of samples of events that contain only resonances, particle correlations, or phase space. A unique feature of this analysis is that every event in the data is assigned to a particular sample. The three-body final state π++p→p+π++π0 is analyzed as an example.

1 data table

No description provided.


Study of three quasi-two-body channels from pi + p interactions at 3.9 GeV/c

Haber, B. ; Hodous, M.F. ; Hulsizer, R.I. ; et al.
Phys.Rev.D 11 (1975) 495-509, 1975.
Inspire Record 107224 DOI 10.17182/hepdata.24871

The pπ+π0 and pπ+π+π− final states from π+p interactions at 3.9 GeV/c have been analyzed by the prism-plot technique and the following three quasi-two-body channels have been studied in detail: π+p→ρ+p, π+p→π0Δ++, and π+p→ρ0Δ++. Results are presented on cross sections, differential cross sections, and single and joint spin density matrix elements. These are compared with the Dar-Watts-Weisskopf absorption model and Reggeized pion-exchange model predictions. Relations among joint spin density matrix elements for ρ0Δ++ are compared with quark-model predictions.

2 data tables

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Dip structures in pi+ p ---> rho+ p at 1.55-1.84 gev/c

Williamson, Y. ; Fung, S.Y. ; Kernan, A. ; et al.
Phys.Rev.Lett. 29 (1972) 1353-1356, 1972.
Inspire Record 75422 DOI 10.17182/hepdata.21440

Results of a high-statistics study of π++p→ρ++p at 1.55-1.84 GeVc are consistent with dominance of π and ω exchange close to threshold. A pronounced dip in ρ00sdσdt at −t≃0.4 GeV2 may be attributed to pion exchange with strong absorption.

9 data tables

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Study of the two-charged-particle final states of 3.9-gev/c pi+- p interactions including a longitudinal-momentum analysis of the one-pion- production channels

Bastien, P.L. ; Carmel, Z. ; Dao, F.T. ; et al.
Phys.Rev.D 3 (1971) 2047-2064, 1971.
Inspire Record 68000 DOI 10.17182/hepdata.23677

We have analyzed the two-prong final states in π+p interactions at 3.9 GeVc. Our result for elastic scattering is σ (elastic) = 6.50±0.1 mb (statistical error only). We find the elastic slope to be 6.61±0.14 (GeVc)−2. We find the elastic forward cross section to be 40.0±1.4 mb(GeVc)2. We have applied a longitudinal-momentum analysis to the one-pion-production channel. We find the cross section for the reaction π++p→π++π0+p to be 2.30±0.06 mb and that for π++p→π++π++n to be 1.45±0.05 mb. For resonance-production cross sections in these channels we find Δ(1236)=0.60±0.07 mb, ρ(760)=0.86±0.06 mb, and diffraction dissociation = 1.69±0.11 mb. We find that we can satisfactorily fit all distributions in the one-pion-production channel without assuming any phase-space production. In the missing-mass channel we observe dominant Δ++(1236) production plus evidence for A2+ production.

15 data tables

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Study of the Reactions pi+ p --> Delta++ pi0 and pi+ p --> Delta++ eta at 5.45-GeV/c

Bloodworth, I.J. ; Jackson, W.C. ; Merdjanian, H. ; et al.
Nucl.Phys.B 81 (1974) 231-248, 1974.
Inspire Record 1399 DOI 10.17182/hepdata.32198

Results are presented on the quasi-two body reactions π + p → Δ ++ π 0 and π + p → Δ s ++ η and 5.45 GeV/ c . Differential cross sections and Δ ++ spin density matrix elements in the t -channel and s -channel helicity systems are presented and compared with a Regge exchange model and the dual absorptive model.

8 data tables

LINEAR BACKGROUND ASSUMED.

VALUE OBTAINED FROM 4-PRONG EVENTS USED, I. J. BLOODWORTH ET AL., NP B39, 525 (1972).

NORMALIZED TO QUOTED TOTAL CROSS SECTION. NO BACKGROUND SUBTRACTION.

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STUDY OF DELTA++ PRODUCTION IN THE REACTION pi+ p ---> pi+ pi0 p AT 13.1-GeV/c

Scharenguivel, J.H. ; Gutay, L.J. ; Gaidos, J.A. ; et al.
Nucl.Phys.B 36 (1972) 363-372, 1972.
Inspire Record 67685 DOI 10.17182/hepdata.33005

We have measured the production and decay angular distributions of the reaction π + p→ π O Δ ++ at 13.1 GeV/ c incident momentum. For − t > 0.1 (GeV/ c ) 2 the data is well described by M1 ϱ-exchange models, the best results being obtained from a weak cut model with a wrong signature nonsense zero. For − t < 0.1 (GeV/c) 2 there is evidence for the existence of other exchange mechanisms.

5 data tables

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Two-prong fitted channels at 11.7 gev/c

Evans, D. ; Neat, K. ; Caso, C. ; et al.
Nuovo Cim.A 16 (1973) 299-314, 1973.
Inspire Record 87004 DOI 10.17182/hepdata.37784

A sample of 43000 two-prong events obtained at a momomentum of 11.7 GeV/c is used to determine the cross-sections of the fitted channels, and to study the reaction π+p→π+pπ0. We investigate in particular the quasi-two-body channels π0Δ++ and ρ+p.

6 data tables

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PRISM Plot Analysis of the Reaction pi+ p --> p pi+ pi+ pi- at 16-GeV/c

The AACHEN-BERLIN-BONN-CERN-CRACOW-HEIDELBERG collaboration Deutschmann, M. ; Schmitz, P. ; Schulte, R. ; et al.
Nucl.Phys.B 86 (1975) 221, 1975.
Inspire Record 104924 DOI 10.17182/hepdata.32122

A study of the reaction π + p → p π + π o at 16 GeV/ c incident momentum has been made using the prism plot analysis to reject background events arising from elastic and multineutral contaminations and to separate different reaction channels ( ϱ + p, g + p, Δ + π + , Δ ++ π o , π + (p π o ) DD ). Cross sections, invariant mass distributions and production and decay angular distributions are presented. For the channel corresponding to proton diffraction dissociation strong violation of both s - and t -channel helicity conservation is found for low values of the (p π o ) mass. We demonstrate that the prism plot method provides a better separation of background events than conventional methods using kinematic cuts.

2 data tables

STATISTICAL ERRORS ONLY.

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Study of the Reactions pi+ p --> pi0 Delta++ (1236), eta Delta++ (1236) and eta-prime Delta++ (1236) at 16-GeV/c

The Aachen-Berlin-Bonn-CERN-Cracow-Heidelberg collaboration Honecker, R. ; Laven, H. ; Becker, L. ; et al.
Nucl.Phys.B 131 (1977) 189-208, 1977.
Inspire Record 122492 DOI 10.17182/hepdata.35195

The reactions π + p giving π 0 Δ ++ (1236), η (549) Δ ++ (1236) and η ′(958) Δ ++ (1236) are studied at 16 GeV/ c . Cross sections, differential cross sections and Δ ++ (1236) spin density matrix elements are presented. The π 0 Δ ++ (1236) differential cross section d σ d t′ indicates a dip towards t ′ = 0 and has a minimum at t ′ ≅ 0.6 GeV 2 . The Δ ++ (1236) spin density matrix elements are consistent with the predictions of the Stodolsky-Sakurai model, except perhaps near the forward direction. For ηΔ ++ (1236), the differential cross section d σ d t′ turns over in the forward direction and presents no further structure. SU(3) sum rules are tested and found to be approximately satisfied. The data agree with factorization of ϱ exchange. The effective A 2 trajectory is calculated and found to be consistent with that reported from the reaction π − p → η n.

7 data tables

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NORMALIZED TO THE TOTAL CROSS SECTION OF 49 MUB.

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