A ( K π π ) + mass enhancement is observed in the reactions K − p → Ξ −K o + π + π o − when events with a small (K − → Ξ − ) four momentum transfer squared are selected. The signal is also visible in the reaction K − p → Ξ − π + + neutrals. The enhancement, centered at 1.28 GeV, is seen to decay preferentially into Kϱ with spin-parity J P = 1 + . The cross section for K − p→ Ξ − C + (1.28) with C + → K ϱ at 4.15 GeV/c incident K − momentum is (6.2 ± 0.6) μ b.
ASSUMING ISOSPIN HALF FOR C(1280)+ AND C(1400)+. FOR C(1280)+, D(SIG)/DU HAS SLOPE OF 1.60 +- 0.30 GEV**-2. THESE AXIAL VECTOR RESONANCES ARE HERE ENCODED AS QLOW(1240)+ AND QHIGH(1340)+.
Significant production of (2030) is observed in the channel K − p → (Σ K − K + from a high statistics bubble chamber exposure at 4.2 GeV/ c . The mass and width are determined to be 2024 ± 2 MeV and 16 ± 5 MeV respectively. Apart from Σ K , the only other decay channel is found to be Λ K .
ASSUMING XI(2030) HAS ISOSPIN HALF, CROSS SECTIONS CORRECTED FOR UNOBSERVED NEUTRAL DECAYS.
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 ′.
No description provided.
No description provided.
ALL EVENTS WITH 1.46<M(KS KS)<1.60GEV.
We have studied the production and decay of the D(1285) meson in the reaction K − p→ Λ D at an incident K − momentum of 4.2 GeV/ c . The cross section for this reaction is 11 ± 3 μ b and the branching ratios D→ KK π /D → ηππ and D → 4 π /D → ηππ are found to be 0.42 ± 0.15 and 0.7 ± 0.5, respectively. The proportion of D → ηπ + π − going through the intermediate δ ± π ∓ states is 0.72 ± 0.15. Forward and backward exchange mechanisms are found to contribute in the ratio 3 : 2.
ABOUT 60 PCT OF THE D(1285) PRODUCTION OCCURS IN THE FORWARD HEMISPHERE.
The backward production of the B(1235) meson is studied in the reaction K − p → Σ − π + ω . This reaction is observed in the final state Σ − π + π + π − π 0 . A π + ω mass enhancement is visible in the region of the B meson for events with small | u |K − → Σ − ) squared four-momentum transfer. The properties of the enhancement agree with those of the B meson. The cross section for K − p → Σ − B + at 4.15 GeV c incident K − momentum is (3.2 ± 0.5) μb . The backward production of the B meson is compared with similar baryon exchange productions of the A 1 and C(Q 1 ) axial vector mesons observed in the same experiment.
No description provided.
No description provided.
A spin-parity 1 + ϱπ enhancement is observed for the 3π mass spectrum in the reaction K − p → Σ − π + π + π − where events with a small (K − → Σ − ) momentum transfer are selected. The mass (1040 MeV) and width (230 MeV) of this enhancement are reminiscent of the A 1 → ϱπ bump which has mainly been observed in the diffractive-like processes. The cross section for this enhancement at 4.15 GeV/ c incident K − momentum is (3.6 ± 0.5) μ b.
No description provided.
No description provided.
We present differential cross sections and the Σ + polarization for the reactions K − p → π ∓ Σ ± using data from a high statistics bubble chamber experiment at 4.2 GeV/ c incident momentum. The statistical level allows a detailed analysis of these reactions over the whole t range. Several significant structures are observed. Comparisons are made with SU(3)-related reactions; for backward production of π − Σ + such a comparison shows good evidence for Δ exchange. The exotic forward peak in K − p → π + Σ − is definitely confirmed.
Axis error includes +- 5/5 contribution.
Axis error includes +- 5/5 contribution.
Axis error includes +- 5/5 contribution.
A study of inclusive Ξ − production from a high statistics K − p experiment at 4.2 GeV/ c has been made. The total Ξ − production cross section is 157 ± 8 μ b. Approximately 15% of the Ξ − arise from decay of the Ξ ∗0 (1530) resonance. The polarization of the Ξ − is found to be negative and is nearly equal in value to that of the Λ 0 from the inclusive reaction K − + p → Λ 0 + anything. An analysis of the inclusive production of Ξ − has been made in the framework of the triple-Reege formalism.
No description provided.
No description provided.
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.
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