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11.
Three- and four-body final states with strange particles are studied in π+p and π?p interactions at 16 GeV/c. We present cross sections and investigate their energy dependence. Production mechanism, resonance production and quantum number transfer are discussed. Strong Y1(1385) production is found in the reaction π+p → ΛK+π+, while the corresponding π?p reaction is dominated by production of K1(890). In the NKKπ channels, the K and K are produced mainly at the same vertex, i.e. non-strangeness exchange ΔS = 0 is dominant (about 75% of the cases), whereas in the ΛKππ channels, the Λ and K are more frequently produced at opposite vertices, i.e. |ΔS| = 1 exchange is important (about 60% of the cases). Results on the polarization of the lambdas produced in the π+p reactions are given.  相似文献   
12.
Rotational motion loses its coherence as a function of the nuclear internal excitation energy. The damping process does not proceed in a continuous fashion and scars of discrete rotational bands are found, inbedded in a background of damped rotational states, regardless whether the calculations are carried out using effective or “random” forces. The complexity of the damping mechanism is revealed in the lineshape of the ridges in theγ-γ correlation spectrum.  相似文献   
13.
Two examples of charmed baryon production by neutrinos have been observed in BEBC filled with hydrogen. Both events fit uniquely the reaction νp → μ?pK?π+π+ and thus apparently violate the ΔS = ΔQ rule. None of the appropriate mass combinations is consistent with the mass values of the D0 and D+ mesons. However, for the mass combinations of the pK?π+ systems, values of (2.285 ± 0.005) GeV and (2.280 ± 0.003) GeV are found for event 1 and 2, respectively. These values agree with the mass of (2.285 ± 0.006) GeV for the Λc+ charmed baryon determined recently in e+e? collisions at SLAC.  相似文献   
14.
Data are presented on the reactions K?p → Δ++ + anything at 10 and 16 GeV/c and π?p → Δ++ + anything at 16 GeV/c. In the K?p reaction, scaling is observed between 10 and 16 GeV/c in the variable M2/s. The scaling occurs at relatively low values of M in marked contrast to the reaction π+p → Δ++ + anything. This result can be explained by duality arguments on a triple Regge picture, since the exchanged reggeon-incident particle scattering is exotic. Comparison of the π?p reaction, which is similarly exotic, with the K?p reaction at the same energy gives further evidence for factorization in pomeron-dominated inclusive reactions.  相似文献   
15.
The average transverse momentum squared, 〈p2〉, of hadrons is studied as a function of W2 and of Q2 for ν and ν interactions on an isoscalar target. An increase of 〈p2〉 with W2 is observed for the hadrons emitted forward in the hadronic c.m.s. The p dependence of the fragmentation function is found to factorise from the structure function at fixed W, but does not factorise at fixed Q2. Unlike the case of forward-going particles, the 〈p2〉 of hadrons going backward in the c.m.s. shows no strong dependence on W2.  相似文献   
16.
The transverse momentum distributions of hadrons produced in neutrino-nucleon charged current interactions and their dependence onW are analysed in detail. It is found that the components of the transverse momentum in the event plane and normal to it increase withW at about the same rate throughout the availableW range. A comparison withe + e ? data is made. Studies of the energy flow and angular distributions in the events classified as planar do not show clear evidence for high energy, wide angle gluon radiation, in contrast to the conclusion of a previous analysis of similar neutrino data.  相似文献   
17.
18.
In a neutrino-proton experiment performed with the bubble chamber BEBC, which was exposed to the wide-band neutrino beam of the CERN SPS, the semi-inclusive reaction νp→μ?h± + X is studied where h± is a hadron of a chosen type. Non-factorization of the semi-inclusive cross section is investigated in terms of double moments with respect to Bjorken-x and the energy fraction z and comparisons are made with predictions of perturbative QCD in next-to-leading order.  相似文献   
19.
Exposures of the Ne/H2 filled Big European Bubble Chamber (BEBC) to a dichromatic neutrino (antineutrino) beam produced by 400 GeV protons of the CERN SPS yielded ~ 3100 events with a negative, and ~ 1100 with a positive, muon. The neutrino flux is determined from the muon flux in the shielding. Assuming a linear energy dependence of the cross section, the values σE between 20 and 200 GeV are found to be 0.657 ± 0.012 (stat.) ± 0.027 (syst.) and 0.309 ± 0.009 (stat.) ± 0.013 (syst.) cm2 (GeV nucleon)?1, for neutrinos and antineutrinos, respectively. The scaling variable q2E decreases significantly with increasing energy both for neutrinos and antineutrinos.  相似文献   
20.
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