We present a new technique for analyzing multibody states. This analysis makes possible the selection of samples of events that contain only resonances, particle correlations, or phase space. A unique feature of this analysis is that every event in the data is assigned to a particular sample. The three-body final state π++p→p+π++π0 is analyzed as an example.
No description provided.
We have investigated the ρ-meson production mechanism in the three reactions π±p→ρ±p and π−p→ρ0n at 3.9 GeV/c (s=8.2 GeV2) using the prism-plot technique. Differential cross sections at all momentum transfers are presented. A significant backward peak has been found in all three reactions. The differential cross sections for these backward peaks are given and are compared with the equivalent pion elastic and charge-exchange cross sections in the backward direction. Using a linear combination of the three differential cross sections we have isolated the I=0 exchange contribution in the forward direction. This differential cross section has a zero at −t=0.45 (GeV/c)2 and is fitted by the dual absorptive model of Harari with an interaction radius of ∼ 1.2 F. The total I=0 cross section is calculated and compared with similarly determined cross sections at higher momenta. An analysis of the properties of the other possible spin-parity exchanges is also presented.
SLOPE FITTED OVER 0.05 < -T < 0.3 GEV**2.
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We have done an inclusive study of ϱ 0 production in π − p interactions at 15 GeV/ c . Evidence for two different production mechanisms, in addition to the known quasi two-body processes, is presented: production of ϱ 0 's in the central region of rapidity similar to the “pionization” region seen in the inclusive studies of pions; and forward production in the beam dissociation region of rapidity. Cross sections and rapidity distributions for the ϱ 0 are given inclusively and by topology, and the results are compared with similar studies at other energies and with other incident particles. Results are also presented for the semi-inclusive reaction π − p → p ϱ 0 + X − and the exclusive final state p π − ϱ 0 .
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The pπ+π0 and pπ+π+π− final states from π+p interactions at 3.9 GeV/c have been analyzed by the prism-plot technique and the following three quasi-two-body channels have been studied in detail: π+p→ρ+p, π+p→π0Δ++, and π+p→ρ0Δ++. Results are presented on cross sections, differential cross sections, and single and joint spin density matrix elements. These are compared with the Dar-Watts-Weisskopf absorption model and Reggeized pion-exchange model predictions. Relations among joint spin density matrix elements for ρ0Δ++ are compared with quark-model predictions.
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The reactions π + p giving π 0 Δ ++ (1236), η (549) Δ ++ (1236) and η ′(958) Δ ++ (1236) are studied at 16 GeV/ c . Cross sections, differential cross sections and Δ ++ (1236) spin density matrix elements are presented. The π 0 Δ ++ (1236) differential cross section d σ d t′ indicates a dip towards t ′ = 0 and has a minimum at t ′ ≅ 0.6 GeV 2 . The Δ ++ (1236) spin density matrix elements are consistent with the predictions of the Stodolsky-Sakurai model, except perhaps near the forward direction. For ηΔ ++ (1236), the differential cross section d σ d t′ turns over in the forward direction and presents no further structure. SU(3) sum rules are tested and found to be approximately satisfied. The data agree with factorization of ϱ exchange. The effective A 2 trajectory is calculated and found to be consistent with that reported from the reaction π − p → η n.
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NORMALIZED TO THE TOTAL CROSS SECTION OF 49 MUB.
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Results from a high-statistics experiment involving an exposure of the SLAC 82-in. hydrogen bubble chamber to a beam of 8-GeV/c π− yielding a final state of π−π+π−p are presented. Copious production of ρ, Δ++, and f is found. Considerable quasi-two-body production in which one particle decays to one of the above resonances is also observed. Some double-resonance production involving baryon and meson resonances is also seen. The production properties of ρ, Δ++, and f mesons are well described by a double-Regge model.
TOPOLOGICAL CROSS SECTIONS. FIRST 2 PRONG VALUE CONTAINS ELASTIC. 0PRONG IS TAKEN FROM A SMALLER AND DIFFERENT PARTIAL SAMPLE.
CROSS SECTION CALCULATED VIA THE OPTICAL THEOREM AS A CROSS CHECK.
SPECIFIC CHANNEL CROSS SECTIONS.
From a study of 8-GeV/c π−p interactions, the various two-pion and four-pion decay channels available to the g− meson have been investigated. Our results indicate that the dominant 4π decay modes involve intermediate ρ and ω production without significant A2 formation.
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Results of a high-statistics study of elastic scattering and meson resonances produced by π−p interactions at 8 GeV/c are presented. Large statistics and small systematic errors permit examination of the complete kinematic region. Total differential cross sections are given for ρ0,−, f0, g0,−, Δ±, Δ0, and N* resonances. Spin-density matrix elements and Legendre-polynomial moments are given for ρ, f, and Δ resonances. The results for ρ0 and f0 resonances are compared with the predictions of a Regge-pole-exchange model. Properties of the above resonances are compared and discussed. In particular, we present evidence that the ρ0 and f0 production mechanisms are similar. The similarity of the g0 t distribution to that of the ρ0 and f0 suggests a common production mechanism for all three resonances.
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SLOPE REFERS TO EXPONENTIAL FIT IN U.
The reactions π + p → π + (K + K − )p and pp → p(K + K − )p where the K + K − system is centrally produced have been studied at 85 GeV/ c . The K + K − spectrum contains several structures in the regions of S ∗ ø , f A 2 and f′. Structure is observed in the 1.7 GeV mass region which cannot be attributed to the g meson. The most likely interpretation of the data is that we observe the θ with a mass of 1.742 GeV and a new resonance at a mass of 1.629±0.010 GeV with a width of 0.082±0.030 GeV.
No description provided.
The reactions π + p → π + ( K + K + K − K − ) p and pp → p ( K + K + K − K − ) p in which the K + K + K − K − system is centrally produced have been studied at 85 GeV c . Evidence is found for φφ production. The relative rates for production of φφ , φK + K − and K + K + K − K − have been determined.
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