Properties of Σ ± (1385) inclusively produced in 4.2 GeV/ c K − p interactions are studied. Inclusive cross sections are presented together with differential cross sections as functions of x and p t 2 for both Σ + (1385) and Σ − (1385). The complete density matrix for Σ + (1385) production at small momentum transfer is studied as a function of t and of recoil mass MM 2 . Substantial agreement with the predictions of the additive quark model is found. The Σ + (1385) production in the target fragmentation region is studied in the framework of the triple-Regge model.
Axis error includes +- 5/5 contribution (ERROR OF NORMALIZATION).
Axis error includes +- 5/5 contribution (ERROR OF NORMALIZATION).
Axis error includes +- 5/5 contribution (ERROR OF NORMALIZATION).
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).
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 ( 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)+.
The vector meson production, hypercharge exchange reactions K − p → ( φ , ω , ϱ ) Λ and ( φ , ϱ ) Σ 0 are studied at 4.2 GeV/ c incident momentum. The data come from a high statistics bubble chamber experiment with a sensitivity of ∼ 120 events/μb. Total and differential cross sections are presented. The vector meson density matrix elements and hyperon polarization are investigated as functions of momentum transfer. Amplitude analyses are performed for all five reactions. The results are compared with duality and quark model predictions, as well as used to test current ideas in two-body phenomenology.
ERRORS INCLUDE THE 5 PCT MODEL ERROR BUT NOT THEORETICAL RESONANCE PARAMETRIZATION ERRORS.
No description provided.
No description provided.
The reaction of K − p → Σ + (1660) π − was studied in a 65 event/μb sample of Σππ(π), Λππ(π) and p K 0 π − final states. The main production features observed are that the Σ (1660) decaying into Σππ is mostly Λ (1405) π and is produced only at small t ; the Σ (1660) decaying into Σπ shows both forward and backward production. This confirms earlier results suggesting the existence of two Σ (1660) resonances. An Adair analysis and a (model-dependent) moments analysis find a J = 3 2 preference for the Σ + (1660)→ Λ (1405) π + → Σ + π − π + ; a Dalitz-Miller analysis of the decay Σ + (1660) → Λ (1405) π + → Σ − π + π + determines J P to be 3 2 − . For the Σ + (1660) → Σ 0 π + a moments analysis suggests J = 3 2 . Branching ratios are determined, which (with the exceptation of the Λ (1405) π mode) are in reasonable agreement with results from formation experiments for the J P = 3 2 − Σ(1660) resonance. We compare our branching ratios with SU(3) and SU(6) predictions; the latter comparison suggests that, unless there is strong configuration mixing, Σ (1660) → Λ (1405) π , if 3 2 − , cannot be a member of the (70, 1 − ) multiplet.
No description provided.
VALUES IN STRONG DISAGREEMENT WITH THE STODOLSKY-SAKURAI MODEL PREDICTIONS.
PRODUCTION CROSS SECTIONS. BRANCHING RATIOS ARE PRESENTED IN TABLE 8.
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.
No description provided.
No description provided.
No description provided.
Using a high statistics sample of K − p interactions at 4.2 GeV/ c , the production and decay properties of the Ξ ∗ (1820) are discussed. The mass and width are found to be M = (1823 ± 2) MeV and Γ = (21 ± 7) MeV. Evidence is found for Ξ ∗ (2030) in the Σ K ̄ channel and for a new Ξ ∗ at a mass of 2120 MeV in the ΛK − channel.
XI(1820)- PRODUCTION CROSS SECTIONS ARE FOR -UP < 3 GEV**2 AND ARE CORRECTED FOR ISOSPIN AND UNSEEN DECAY MODES.
No description provided.
In a high statistics CERN 2 m bubble chamber experiment the differential cross sections and polarizations of the Λ for the reactions K − p → Λπ 0 , Λη , Λη ′ at 4.2 GeV/ c have been measured. The reaction K − p → Λη exhibits a pronounced dip around − t ∼0.5 ( GeV / c ) 2 and all three reactions show a significant backward peaking (− u < 1.0 (GeV/ c ) 2 ). The Λ polarization in the reaction K − p → Λπ 0 is measured to be significantly different from zero throughout most of the available t -range. Forward cross sections enable a determination of R T , the ratio of singlet/octet coupling η 1 KK ∗∗ η 8 KK ∗∗ . Backward cross sections are utilized to estimate the effective η-nucleon coupling constant g η NN 2 over the − u range 0–1.5 ( GeV /c) 2 .
QUOTED VALUES OF THE KINEMATIC LOWER LIMITS OF -T AND -U.
Axis error includes +- 5/5 contribution.
Axis error includes +- 5/5 contribution.
In this letter results are presented on the reactions K − p → K 0 n and K − p → K − p from a high statistics CERN 2-metre hydrogen bubble chamber exposure at 4.15 GeV/ c . The behaviour of the differential cross section as a function of four-momentum transfer shows remarkable similarities between the two reactions studied. From a comparison of our data with K + p elastic scattering at 4.27 GeV/ c we draw some conclusions concerning the magnitude of the contributing amplitudes.
No description provided.
No description provided.