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.


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

No description provided.

NORMALIZED TO THE TOTAL CROSS SECTION OF 49 MUB.

No description provided.

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Study of the Reaction pi+ p --> omega Delta++ (1236) at 16-GeV/c

The Aachen-Berlin-Bonn-CERN-Cracow-Heidelberg collaboration Grassler, H. ; Honecker, R. ; Laven, H. ; et al.
Nucl.Phys.B 115 (1976) 365-384, 1976.
Inspire Record 110390 DOI 10.17182/hepdata.35656

The reaction π + p→ ωΔ ++ (1236) is studied at 16 GeV/ c . Cross section, differential cross section, single and joint spin-density matrix elements are given and the correlations between the ε and Δ ++ (1236) decay angular distributions are investigated. Natural and unnatural spin-parity exchanges contribute to this reaction in roughly equal amounts. Natural exchanges lead predominantly to Δ ++ (1236) with helicity ± 3 2 , while unnatural exchanges lead predominantly to Δ ++ (1236) with helicity ± 1 2 and to ε with helicity zero. Furthermore, unnatural exchanges are small at t ′≅0.2 GeV 2 compared to other t ′ values, which may be due to the nonsense wrong-signature-zero of the B-meson exchange. Quark model relations are found to be satisfied by the data.

6 data tables

CORRECTED FOR UNSEEN OMEGA DECAY MODES. 'SLICE METHOD' USED TO HANDLE RESONANCE TAILS AND BACKGROUND.

FROM EVENTS WITHIN MASS-CUTS FOR RESONANCES AND NORMALIZED TO TOTAL CROSS SECTION.

'ALL'.

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Study of the Reaction pi+ p --> rho0 Delta++ (1236) at 16-GeV/c

The Aachen-Berlin-Bonn-CERN-Cracow-Heidelberg collaboration Honecker, R. ; Lauscher, P. ; Laven, H. ; et al.
Nucl.Phys.B 106 (1976) 365-384, 1976.
Inspire Record 108897 DOI 10.17182/hepdata.35864

The reaction π + p → ϱ 0 Δ ++ (1236) at 16 GeV/ c has been studied. Cross section, differential cross section, single and joint spin-density matrix elements are given. Correlations between the ϱ 0 and Δ ++ (1236) decay distributions are observed. Unnatural spin-parity exchanges, mainly observed at small t ' values, dominate the ϱ 0 Δ ++ (1236) production. The natural exchange contributions are only (7 ± 2)% and become as important as the unnatural exchanges beyond t ' = 0.3 GeV 2 . Contributions to Δ ++ (1236) helicity 3 2 states do not exceed 20% of the total ϱ 0 Δ ++ (1236) cross section and are mainly due to unnatural exchanges.

6 data tables

'SLICE METHOD' USED TO HANDLE RESONANCE TAILS AND BACKGROUND.

FROM EVENTS WITHIN MASS-CUTS FOR RESONANCES AND NORMALIZED TO TOTAL CROSS SECTION.

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