Observation of a High-Mass Delta++ Produced in Association with K*, rho and omega

Chung, S.U. ; Protopopescu, S.D. ; Eisner, R.L. ; et al.
Phys.Lett.B 57 (1975) 384-388, 1975.
Inspire Record 98501 DOI 10.17182/hepdata.27841

Strong evidence is presented for quasi-two-body production of a π + p enhancement with mass 1881±6MeV and width 219±23MeV, recoiling off vector mesons ϱ O and ω from π + p interactions at 7.1 GeV/ c and K * o (890) from K + p interactions at 12 GeV/ c . The most probable J P assignment for this object is 7/2 + , making it a likely candidate for the Regge recurrence of Δ(1236).

2 data tables

JACKSON FRAME.

JACKSON FRAME.


Omega Production in the Reaction pi- p --> pi+ pi- pi0 n at 8-GeV/c and 12-GeV/c

Dowell, J.D. ; Garvey, J. ; Jobes, M. ; et al.
Nucl.Phys.B 108 (1976) 30-44, 1976.
Inspire Record 100856 DOI 10.17182/hepdata.35781

The reaction π − p → ω n has been studied at 8 and 12 GeV / c incident momenta with the CERN Omega spectrometer using a neutron time of flight trigger. The differential cross sections and the ω-decay density matrix elements are presented as functions of the momentum transfer squared − t in the range of 0.02 to 0.80 GeV 2 . The data are used to evaluate the intercept and slope of both the natural and unnatural parity exchange trajectories. Regge exchange amplitude factorisation tests involving the reaction π N → ω N are investigated.

3 data tables

No description provided.

'FIT'.

'FIT'.


Phi-Meson Production in the Reactions pi+- n --> K- K+ n at 6-GeV/c

Cohen, Daniel H. ; Ayres, D.S. ; Diebold, R. ; et al.
Phys.Rev.Lett. 38 (1977) 269, 1977.
Inspire Record 110508 DOI 10.17182/hepdata.21019

A sample of 1200 ϕ mesons produced in the Zweig-rule-forbidden reactions π±N→ϕN shows a flat t distribution (slope=1.7 ± 0.2 GeV−2) and a cross section suppressed by 0.0032±0.0004 relative to π−p→ωn. Natural-parity-exchange ω and ϕ production have similar t dependences, while ω and ϕ production by unnatural-parity exchange differ markedly. Interference between the ϕ and the underlying K¯K S wave indicates substantial nucleon-spin incoherence between the amplitudes for ϕ and S-wave production.

3 data tables

Axis error includes +- 10/10 contribution (RES-DEF(RES=PHI,BACK=CORRECTED)).

Axis error includes +- 10/10 contribution (RES-DEF(RES=PHI,BACK=CORRECTED)).

STATISTICAL ERRORS ONLY.


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.

More…