Results are presented for the quasi two-body hypercharge exchange reactions of the type using data from a high statistics bubble chamber experiment. Total and differential cross sections and the momentum transfer dependence of the meson and hyperon resonance single density matrix elements are discussed. Amplitude analyses are performed for the first two reactions. The results are compared with quark model and duality predictions and with those from other related reactions.
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We have investigated the final states K ∗0 (890)Σ, K ∗0 (890)Σ 0 and K ∗0 (890) Y 1 ∗0 (1385) produced in π − p interactions at 3.93 GeV/ c . We present the differential cross sections and spin density matrix elements for the resonances as functions of momentum transfer, as well as the gL and Σ 0 polarizations. The Σ 0 polarization is found to be positive and maximal. An amplitude analysis is performed for the K ∗ Λ and K ∗ Σ 0 reactions, and it is found that one natural parity transversity amplitude is dominant for the latter.
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The total and differential cross sections of the reactions K − p → π 0 Λ (1520), ηΛ(1520) and η′ Λ(1520) have been measured. Prominent forward peaks are onserved in all three reactions. The first reaction shows also a backward peak. The spin density matrix elements of the Λ(1520) in this reaction are determined. For forward production the results show a remarkable alignment of the Λ(1520) corresponding to an M2 transition in the model of Stodolsky-Sakurai for 3 2 − baryon production.
TOTAL (FORWARD AND BACKWARD) CROSS SECTIONS. THE ERRORS ARE MAINLY SYSTEMATIC.
-TP = (-T - 0.04 GEV**2). MAX(-T) - MIN(-T) = 5.75 GEV**2.
-UP = (-U - 0.20 GEV**2).
A partial-wave analysis of the (3 π ) 0 system produced peripherally in the reaction K − p → π + π − π 0 Λ at 4.2 GeV/ c is presented. The observation of the weak Λ decay allows a determination of all the transversity production amplitudes except for two phases. The production of known resonances having decay modes other than 3 π is used to test the isobar model ansatz. Significant ω(783), φ(1020) and A 2 (1310) production is observed. The spin parity of the ω ∗ (1675) is established as 3 − . No evidence for production of other resonances, such as axial vector-mesons, is found.
No description provided.
Results are presented for the hypercharge exchange reaction K − p→ f ′(1514) Λ at a beam momentum of 4.15 GeV/ c . Total and differential cross sections have been determined. The Λ polarization and the tensor meson density matrix elements are given as a function of t ′.
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ALL EVENTS WITH 1.46<M(KS KS)<1.60GEV.
The reactions K − p→ π − Σ + (1385) and K − p→ π + Σ − (1385) are studied at 4.2 GeV c incident momentum using data from a high statistics bubble chamber experiment corresponding to ∼80 events/μb. The total and differential cross sections are presented. Amplitude analyses are performed and the complete Σ ± (1385) helicity spin density matrices are extracted. The results are compared with the predictions of the additive quark model and exchange degeneracy. A substantial cross section is observed for the reaction K − p→ π + Σ − (1385) in the forward direction, which implies exotic meson quantum numbers in the t -channel. One possible interpretation of this process provides an explanation for the small but significant violations of the additive quark model predictions observed in the reaction K − p→ π − Σ + (1385) at low four-momentum transfer. In the backward direction unnatural parity exchange is shown to give a larger contribution to K − p→ Σ − (1385) π + than natural parity exchange.
Axis error includes +- 5/5 contribution.
Axis error includes +- 5/5 contribution.
Axis error includes +- 5/5 contribution.
Transversity amplitudes and spin density matrix elements are determined for the process K − p → (π + π − ) s-wave ϵ 0 (1385). Predictions of the additive quark model and of duality diagrams are tested and found consistent with the data; this is the first information about the applicability of these models to processes where a scalar object is produced at the mesonic vertex.
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A πω enhancement at 1245 MeV is observed in the reaction K − p → Σ + π − ω. Its properties agree with those of a B meson produced by natural-parity exchange thus establishing a coupling of the B to a K K ∗ system.
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THE DATA FOR B+ PRODUCTION ARE QUOTED FROM CHUNG ET AL., PR D11, 2426 (1975) USING THE SLAC 82 IN HBC. 1.08 < M(PI OMEGA) < 1.38 GEV.
The reaction π − p → A − 2 p at 3.9 GeV/ c incident momentum is studied using data corresponding to the ϱ ° π − , ηπ − and K δ s K − decay modes of the A − 2 . Unnatural parity exchange is found to be important at this energy. The natural parity exchange component of the differential cross section exhibits structure at t ′ ≈ GeV 2 .
CORRECTED FOR ALL A2(1310)- DECAY MODES.
No description provided.
<RHO0 PI-> DATA.
The reactionsπ−p→K0∑0(1385) andπ−p→K+∑−(1385) are studied at an incident momentum of 3.95 GeV/c using data from a high statistics bubble chamber experiment corresponding to approximately 90 events/μb. The total and differential cross sections and the density matrix elements of the Σ(1385) are presented. The results are compared with those obtained for the related processesπpp→K+∑+(1385) and\(K^ -p \to \pi ^ \mp\sum ^ \pm(1385)\) in this energy range. Evidence is presented for the existence of production mechanisms with exotic exchanges in thet channel.
FROM THE CHANNEL PI- P --> LAMBDA K0 PI0 WHICH HAS A CROSS SECTION OF 72 +- 4 MUB.
FROM THE CHANNEL PI- P --> LAMBDA K+ PI- WHICH HAS A CROSS SECTION OF 79 +- 3 MUB.
FORWARD CROSS SECTION.
Forum