Total and differential cross sections ofK*−(890),K*−(890),\(\bar K^{ * 0} \)(890),K*0(890),\(\bar K^{ * 0} \)(1430) andϱ0(770) produced inK−p interactions at 110 GeV/c are presented. The cross sections of the neutral resonances show a smooth increase with energy from 10 to 110 GeV/c incident momentum. For theK*+(890) and theK*0(890), i.e. the resonances with strangenessS=+1, this rise is quite significant: their cross sections practically double between 32 GeV/c and 110 GeV/c incidentK− momentum. About 50% of the neutral kaons and 30% of charged pions produced inK−p interactions at our energy are found to be decay products of the resonances considered.
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Inclusive e+e− production in 17-GeV/c π−p collisions has been measured. An excess of e+e− pairs over those from known sources for 0.1<~mee<~0.6 GeV and x<0.5 was found. No evidence is found for enhancements in specific final states involving electrons and photons or charged particles. The photon multiplicity associated with these pairs is measured.
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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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Results are presented on inclusive production of resonant and non-resonant particle systems produced inK+p interactions at 32 GeV/c. We compareK*+(892),\(\bar \Sigma ^{ *- } \)(1385), Σ*±(1385), and ϱ0 inclusivex-spectra with the ones of non-resonantKs0π±,\(\bar \Lambda \pi ^ -\), Λπ± and π+π− pairs at the same effective mass. Resonance-particle pairsK*+π±, Σ*+π−, and\(\bar \Sigma ^{ *- } \pi ^ -\) are also studied together with non-resonant tripletsKs0π±, Λπ+π−,\(\bar \Lambda \pi ^ -\pi ^ -\). The invariantx-spectra of resonant particle pairs decrease less rapidly withx then the corresponding non-resonant pairs. Comparison with quark-recombination predictions indicates that the particles, resonances and multiparticle systems are probably created off a single valence quark or diquark instead of carrying all possible valence-quarks.
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The study of π ± , π 0 , K 0 and Λ production in the fragmentation regions (| x |0.2) of K − p interactions at 70 GeV/ c shows that the x -dependence of each invariant cross section is well described by the power law (1−| x |) n suggested by the dimensional counting rule. Furthermore, pion production is found, both in K − and proton fragmentation regions, to be very similar to their production in ν( ν ) p interactions as expected from quark-parton models. The quark and diquark fragmentation functions D u π , D uu π and D ud π are extracted from our data.
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Results are presented on two-particle inclusive production inK+p interactions at 32 GeV/c. We study thex1,2=x1+x2 dependence of invariant structure functions of (ππ)-pairs and compare them to single particle inclusive distributions in the fragmentation regions. Distributions of particles observed at Feynmanx2 in association with various “trigger” particles or systems atx1 in the same hemisphere are dicussed in terms of the reduced variable\(\tilde x_2= x_2 /(1 - |x_1 |)\). We further present absolute production rates and production ratios of π+'s and π−'s associated with π±,Ks0, Λ,\(\bar \Lambda \),K*+ (890), (Ks0π+), and (π+ π−)-triggers, and compare them with qualitative predictions of the quark recombination model. Forwardbackward correlations between (Ks0π±), (Ks0,p), (Λ, π−),\((\bar \Lambda \pi ^ \pm)\), and (p, π−) pairs are also discussed.
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New data on the inclusive production of the non-strange resonances ϱ0(770), ω(783), ϕ(1020) andf(1270) inK− p interactions at 32 GeV/c are presented. The inclusive production cross sections are equal to (4.32±0.72) mb, (3.7±1.4) mb, (0.65±0.10) mb and (0.91±0.35) mb respectively. Estimates of the topological cross sections are also obtained. The invariant and non-invariantx-distributions for the vector mesons ϱ0 and ϕ indicate the prevalence of forward resonance production in the c.m. system. For the tensorf-meson the rapidity andx-distributions are presented. Thet′-distributions for ϱ0, ϕ, andf have exponential slopes of 0.6±0.1 GeV−2, 1.2±0.2 GeV−2, and 0.8±0.5 GeV−2 respectively. The exponential slope ofpT2-distribution of thef-meson is equal to (2.3±0.5) GeV−2.
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Inclusive ϱ 0 and φ production is investigated in K + p interactions at 32 GeV/ c . Total and semi-inclusive ϱ 0 and φ cross sections, longitudinal and transverse momentum distributions, including 〈 P T versus x dependence are presented. No evidence for a sea-gull effect is observed. Comparison with quark models strongly suggests the possibility that a large fraction of the ϱ 0 and vector mesons are produced as fragmentation products of the incident particles. Study of uncorrelated π + π − pairs in the ϱ 0 mass range provides possible indirect evidence for the existence of diquarks in the proton.
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