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.
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PRODUCTION ANGULAR DISTRIBUTIONS OF SIG(1670D13)+ DIFFER FOR THE TWO FINAL STATES <LAM(1405S01) PI+> AND <SIGMA PION> SUGGESTING THE EXISTENCE OF TWO SIG(1660) RESONANCES.
VALUES IN STRONG DISAGREEMENT WITH THE STODOLSKY-SAKURAI MODEL PREDICTIONS.
π+p, K+p, and pp interactions at 100 GeV are studied using the Fermilab hybrid 30-inch bubble chamber with associated downstream multiparticle spectrometer and an unseparated tagged positive beam. Topological cross sections and charged-particle-multiplicity moments are presented and good agreement is found with Koba-Nielsen-Olesen scaling. The charged-multiplicity second moment, f2cc, and the second moment of produced (+ -) pairs, f2−−, are presented both with and without the diffractive-dissociation events, and are discussed in terms of the two-component model invoked to explain pp multiplicity distributions above 100 GeV. Single-particle inclusive distributions are presented and studied in terms of the Regge-Mueller forms of approach to scaling at asymptotic energies. Pomeron factorization is found to hold in the target-proton-associated backward center-of-mass hemisphere for inclusive particle production by incident π+, K+, and protons.
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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 reactions K L o p→K S o p, π + Λ , π + Σ o have been measured for center-of-mass energies from 1540 to 1610 MeV. Channel cross sections and coefficients of the Legendre polynomial expansion of the differential cross sections and hyperon polarizations are presented. We see no evidence in the πΛ channel for the suggested 3 2 − resonance at 1580 MeV. The cross section for the K S o p channel shows an energy dependence which is not predicted by the existing phase shift solutions based on charged kaon data.
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Results are presented of differential cross-section measurements for the reaction π − p→ π 0 n; π 0 → γγ at 22 incident pion momenta between 618 and 2724 MeV/ c . The results are in good agreement with those of other experiments. They represent the first comprehensive set of high statistics measurements of the π − p charge-exchange differential cross section at closely spaced momenta in the resonance region.
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Using 13.5-GeV beams at Stanford Linear Accelerator Center, we have compared electron and positron inelastic scattering over the range 1.2<|q2|<3.3 (GeV/c)2, 2<ν<9.5 GeV for the four-momentum and energy transfers, respectively. We find the ratio of the cross sections to be e+e−=1.0027±0.0035 (including statistical and systematic effects), with no significant dependence on q2 or ν. This result has appreciably smaller errors than previous attempts to find two-photon-exchange effects in electron or muon scattering.
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We have investigated the inclusive production of γ, KS0, Λ0, and Λ¯0 in 100-GeV/c p¯p interactions in the 30-in. hydrogen bubble chamber at Fermilab. We present various inclusive distributions and compare them with corresponding distributions in 100-GeV/c pp interactions and lower-energy p¯p interactions. We find some evidence for Σ(1385) production but none for K*(890) production. We find evidence for a nonzero Λ0 polarization of -0.45 ± 0.21.
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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.
Differential cross sections for the reactions K−p→K¯0n, K−p→K¯0Δ0, and K+p→K0Δ++ in the region 0<|t|<1.2 GeV2 are presented from a wire-spark-chamber spectrometer experiment performed in a 13-GeV/c separated beam. The results are based on 20 000 Δ++ events, 4600 Δ0 events, and 8500 n events. The line-reversed pair of Δ reactions is used to test Regge exchange degeneracy and an SU(3) sum rule. The energy dependence of all three reactions is studied by comparison with other experiments.
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TMIN IS SO MUCH LESS THAN THE RESOLUTION THAT TP DOES NOT DIFFER SIGNIFICANTLY FROM T.
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