The inclusive production of Σ + (1385) and Σ − (1385) has been studied in K − p interactions at 10 and 10 and 16 GeV/ c . It is found that the cross sections for the reactions K − p → Σ ± (1385) + anything are approximately constant in the energy range form 10 to 32 GeV/ c , being ≈ 350 μ b for Σ + (1385) and ≈ 250 μ b for Σ − (1385). The d σ d p ⊥ 2 distributions for Σ ± (1385) fall off exponentially with increasing p ⊥ 2 , with sloped of about 3 (GeV/ c ) −2 . The d σ /d x distributions for Σ + (1385) and Σ − (1385) are markedly different: the production of Σ − (1385) is symmetrical forwards and backwards in the c.m.s.; for Σ + (1385), the distribution is the same as for Σ − (1385) in the forward direction, but presents a large excess of events in the backward direction. This indicates that for the production of both Σ + (1385) and Σ − (1385) the fragmentation of the incoming kaon is negligible. The fragmentation of the target proton is negligible for Σ − (1385), but it is important for Σ + (1385) and is responsible for the excess (∼100 μ b) of its cross section over that for Σ − (1385).
Axis error includes +- 0.0/0.0 contribution (?////RES-DEF(RES=SIG(1385P13) ,BACK=CORRECTED)//CORRECTED FOR UNSEEN DECAY MODES (PDG 1974)).
Axis error includes +- 0.0/0.0 contribution (?////RES-DEF(RES=SIG(1385P13) ,BACK=CORRECTED)//CORRECTED FOR UNSEEN DECAY MODES (PDG 1974)).
Axis error includes +- 0.0/0.0 contribution (?////RES-DEF(RES=SIG(1385P13) ,BACK=CORRECTED)//CORRECTED FOR UNSEEN DECAY MODES (PDG 1974)).
The inclusive production of K̄ ∗ (890) and K̄ ∗ (1420) is studied in K̄ − p interactions at 10 and 16 GeV/ c . At 10 GeV/ c an enhancement in the ( K ̄ 0 π − ) mass distribution is found at 1.74 GeV, but no clear signal is seen at 16 GeV/ c . The fraction of K 0 ' s coming from decay of the K ∗ (890) or K ∗ (1420) is large, being (50 ± 6)% and (45 ± 5)% at 10 and 16 GeV/ c , respectively. The inclusive cross sections for K ∗− (890) and K ∗0 (890) production are almost constant with energy from 8 to 32 GeV/ c with values of 3.5 and 3.3 mb, respectively. The K ∗ (890) production cross section is studied as a function of transverse and longitudinal variables and found to derive mainly from fragmentation of the incident K − meson. The spectra of K 0 ' s resulting from the decay of K ∗ (890) are studied.
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The inclusive spectra for p p collisions at 22.4 GeV/ c are investigated. We show that the transverse momentum distributions resemble those in high-energy pp interactions and discuss the influence of annihilation processes on the p T 2 distributions. The invariant inclusive cross section for pions in the central region is found to be 28 ± 1 mb. A charge asymmetry is indicated by the y ∗ spectrum in the central region, the asymmetry parameter having the value 0.15 ± 0.01. Finally, we estimate the upper limit of the diffraction dissociation of the beam particle to be 3.68 −0.15 +0.45 mb.
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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.
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A method for the determination of neutron spectra in a bubble chamber experiment is developed. Double differential cross sections for inclusive neutron and lambda production are presented. The n/Λ particle ratios are determined as functions of x and p T ; at p T = 0 GeV/ c they are compatible with the ratios measured in pCu interactions at 24 GeV/ c . Our neutron spectra are compared with spectra for protons produced near the direction of the incident neutron in pn interactions at FNAL and with neutron spectra measured in pp interactions at the ISR. Exchange mechanisms are studied in the framework of single diffraction dissociation and the triple-Regge model. The scattering of virtual pions and kaons on real protons is investigated.
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Inclusive Ξ − production is studied in K − p interactions at 8.25 GeV/ c using about 8000 events. An analysis based on the triple-Regge model shows that the Λ α − Λ γ and Σ β − Σ δ exchanges explain the forward Ξ − production. Ξ(1530) properties are also studied and are found to be similar to those of Ξ − 's. Finally, a study of the production of Ω − based on 67 events shows that Ω's are also produced by hyperon exchange.
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Inclusive Λ production has been studied in K − p interactions at 8.25 GeV/ c using about 69 000 events; the total cross section is found to be 3.35 ± 0.20 mb. A comparison has been made with Σ 0 and Σ(1385) inclusive production. Their influence on the inclusive Λ production is discussed. The inclusive Λ cross section and polarization is interpreted in terms of the triple-Regge model. In the target fragmentation region an effective Regge trajectory is determined which lies closer to the K than to the K ∗ . In the beam fragmentation region the cross-section data indicate an effective Regge trajectory which corresponds to the nucleon, while the polarization data require additional Regge exchanges to be present.
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Results are presented on the inclusive photoproduction of λ and λ for incident photon energies between 25 and 70 GeV. The slope parameter of the p T 2 distribution is found to be 2.83±0.1 GeV −2 for λ and 3.28±0.25 GeV −2 for λ . The x F distributions, measured in the range −0.2 to 0.7, show that while λ are produced centrally, λ production extends to more negative values of x F ; the shapes show no energy dependence and are similar to those in pion-induced reactions. The polarization of the produced λ is less than 10%. The results are discussed in terms of vector dominance and quark fusion models.
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Inclusive and semi-inclusive production of Λ and\(\bar \Lambda\) inK+p interactions is studied at an incident momentum of 70 GeV/c. Cross sections and single particle distributions are presented and compared with data at lower energies. Scaling is observed between 32 and 70 GeV/c in the Feynmanx variable in the target and the beam fragmentation regions for Λ and\(\bar \Lambda\) inclusive production respectively. An increase of Λ (\(\bar \Lambda\)) production is observed in the beam (target) fragmentation regions, whereas the data at 70 and 32 GeV/c are reasonably close in the central region. The dependence of the Λ(\(\bar \Lambda\)) polarization as a function ofx is measured and found to be in general agreement with the results at 32 GeV/c. The (Λ\(\bar \Lambda\)) pair production cross section increases significantly from 32 to 70 GeV/c. The Λ and\(\bar \Lambda\) production associated with an identified proton is also studied.
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