A partial-wave analysis has been performed on the (K − π − π + ) system produced in the reaction K − p → K − π − π + p at 10 and 16 GeV/ c . In the Q mass region it is found that the two dominant states, K ∗ π and Kπ, both in 1 + S wave, are produced with different polarisations, helicity being approximately conserved in the t -channel for K ∗ π and in the s -channel for Kπ. This is in contradiction with the assumption that the amplitude can be factorised into “production” and “decay” parts, and hence that the two amplitudes are fully coherent. The phase variation of the two states do not indicate simple resonance behaviour. It is concluded that the Q-mass enhancement is composite.
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We have studied the reactions K − p → K − π + π − p and K − p → K 0 π − π 0 p at 14.3 GeV/ c using respectively 15 992 and 3723 events. Partial-wave analysis of the region 1.0 < m (K ππ ) < 1.7 GeV have been made using a modified version of the method developed at the University of Illinois.
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Using new data from 100 GeV c π − interactions, we find the energy dependence of the invariant cross-section in the target fragmentation (central) region to be consistent with an A + Bs − 1 2 (C + Ds − 1 4 ) behavior. The leading particle peak near x = + 1 exhibits a width in x which becomes smaller with increasing energy and an integrated cross section which is approximately energy independent.
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We present cross sections for e+e−→hadrons, e+e−, and μ+μ− near 3095 MeV. The ψ(3095) resonance is established as having an assignment JPC=1−−. The mass is 3095 ±4 MeV. The partial width to electrons is Γe=4.8±0.6 keV and the total width Γ=69±15 keV. Total rates and interference measurements for the lepton channels are in accord with μ−e universality.
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Inclusive cross sections and one-particle inclusive spectra are given for neutral K, Λ and Λ produced in K − p and K + p interactions at 32 GeV/ c in the 4.5 m Mirabelle hydrogen bubble chamber at the Serpukhov accelerator. Cross sections for associated production are also given, and the energy dependences of the cross sections and of the x distributions in the central and in the fragmentation regions are discussed.
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The inclusive production of Σ + (1385), Σ − (1385), Λ (1405) and Λ (1523) in K − p interactions at 14.3 GeV/ c is studied. Cross sections are presented and the x dependence of the invariant cross sections is discussed. The density matrices for production of the spin- 3 2 resonances at small momentum transfer to the target are consistent with spin-0 exchange.
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A study of elastic scattering, one-pion production and annihilation reactions in p p interactions at 5.7 GeV/ c was carried out, from the two-prong events, obtained in the hydrogen bubble chamber exposed at CERN.
NUMBER OF EVENTS FOR -T<0.03 GEV**2 CALCULATED BY EXTRAPOLATION.
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We have studied inclusive Δ++(1236) production for |tpΔ|<1.0 (GeV/c)2 in a 50 000 picture exposure of the 30-inch hydrogen bubble chamber to a 205 GeV/c proton beam. The inclusive Δ++ cross section for one hemisphere in the center-of-mass system is (1.30±0.14) mb. The mean charged multiplicity of the system recoiling off the Δ++ is in agreement with that for laboratory π−p interactions at the same energy in the center-of-mass frame. The inclusive Δ++ production is compared to inclusive Λ0 and proton production in the same experiment. The connection between Δ++ production and diffraction is discussed. We find that not all Δ++ come from the decay of a diffractively-produced state. The PT2 distribution for the Δ++ has a slope of (10.5±0.9) (GeV/c)−2 for PT2≲0.2 (GeV/c)2. This slope, together with the decay angular distribution of the Δ++ at small momentum transfer, suggests a strong pion-exchange contribution to the inclusive process. We compare the data to the expectation of a triple-Regge model with ρ- and π-exchange contributions.
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Inclusive cross sections and longitudinal momentum distributions are presented for γ rays produced in K − p and K + p interactions at 32 GeV/c in the 4.5 m Mirabelle hydrogen bubble chamber at the Serpukhov accelerator. The average longitudinal and transverse momentum of neutral pions and the average π 0 multiplicity ▪ 〈 n π 0〉 are estimated. It is found that 〈 n π 0〉 is an increasing function of the number of charged prongs.
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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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No description provided.